Final Report Summary - RELIGHT (Sustainable Recycling of Lighting Products)
Executive Summary:
The Waste Electrical and Electronic Equipment Directive (WEEE Directive) is the European Community directive 2002/96/EC on waste electrical and electronic equipment (WEEE) which became European Law in February 2003, setting collection, recycling and recovery targets for all types of electrical goods including lamps. The directive requires that lamps are collected and recycled and that a recovery rate of 80% is achieved. As incandescent lamps are being successively banned in the EU, the volume of Compact Fluorescent Lamps (CFLs) is increasing rapidly and to be able to meet the legislation, 80% of all CFLs need to be recycled and 80% of the lamp material needs to be reused/recycled.
The advantage of CFLs is the saving of energy during use compared to that of the filament lamp. However, at end of life the CFL is significantly more difficult to recycle, partly due to the presence of hazardous mercury within the lamp, but also due to the different materials of construction.
The aim of RELIGHT project has been to test and to develop novel technologies in the niche application of CFL recycling, to find a cost effective means of recovering high value materials from the product.
The outcomes of the project have determined the type, scale, set up and cost of process equipment that will turn a CFL lamp into clean, high value constituent materials of glass, plastic, metal and phosphor powder. A compact crusher has been developed to separate these component parts and prepare them for sale.
The project has also provided a relatively low cost, medium throughput technology for the recovery of mercury from the phosphor powder, enabling the mercury to be recovered and the resultant non-hazardous powder to be reused. The powder contains several valuable rare earth metals – this process will better and more cost effectively prepare these powders for sale to recovery facilities in Europe, and enable a higher price to be paid to the SMEs.
Project Context and Objectives:
There are recycling technologies available on the market already. Currently, two types of techniques are utilised for recycling of fluorescent lamps. One technique is known as "end cut", employing a process by which both ends of the fluorescent tube are removed before the materials are separated and processed to a high purity product. The other technique is known as "crush and sieve". It crushes the complete product, after which the various components are separated and processed. There are also existing technologies to remove mercury from fluorescent powder and other mercury contaminated material. However, there are currently no cost-effective methods allowing the recyclers to meet the stricter requirements for mercury content below 1-2ppm in materials for re-use.
These existing techniques will be able to handle the linear (TL) fluorescent lamps and separate into an acceptable level with clean, recyclable glass. CFLs will also be possible to be separated into clean, recyclable glass. However, current methods result in a contamination of between 1-5% plastic in the glass, which means that recycling to aggregate is the main viable outlet. To recycle to higher use end markets the glass needs to be less contaminated with plastic, with the overall aim of achieving closed loop recycling of CFL glass a realistic aim.
However, for CFLs the glass only represents ~50% of the material and will therefore not meet the requirement of 80% recycling level and further work is needed to increase the proportion and value of recovered materials.
The primary advantage of recycling CFLs today is diversion of mercury from landfill sites; the actual scrap value of the materials salvaged from a discarded lamp is insufficient to offset the cost of recycling. The target for small recyclers such as WISER and DISMECO is the development of cost effective, practical and environmental sound methods for recycling of compact fluorescent lamps. There are three main issues that need to be addressed in order to achieve the legislated recycling targets;
1. Separation of e-base (bulb base containing plastic and electronic components) into recyclable components.
2. Reduction of mercury in “clean fractions” from 5-10 ppm down to 1-2 ppm.
3. Reduction of mercury in fluorescent powder from 2000 ppm down to 1-2 ppm.
These processes need to be cost effective and self-financed by the scrap value of the materials salvage. This means that today’s known and available technologies could not be used. A lot of work has been done by MRT and others, scaling existing technical solutions to meet these requirements, but without success. To reach these targets, innovative new technologies and processes are required
Project Objectives in Improving Recovery Technology
The RELIGHT project has tested and developed novel technologies in the niche application of CFL recycling, to determine a cost effective means of recovering high value materials from the product.
To be able to meet the WEEE Directive requirements and handle the increasingly large volumes of hazardous CFL and other gas discharge lamp waste best practice in lamp recycling needs to be improved and made commercially plausible. If this is achieved, there is a huge global market potential. The number of End of Life Lamps (EOLs) will more than double in the nearest future and the collection levels will increase from 10-20% up to 80-90%. First on the market with a technically and commercially effective process will be able to take a large part of this volume and be able to solve a huge environmental problem.
There is not only a strong market force from RELIGHT SME participants point of view to achieve cleaner fractions; it is also a requirement of the legislation. It is the view of the participants that to achieve only recycling of lamps to low value outlets is not ambitious, and that the industry should be seeking to recover valuable materials back to a high value use. These issues are prerequisite for the lamp recycling industry.
The RELIGHT project outcomes determined the type, scale, set up and cost of process equipment that will turn a CFL lamp into clean, high value constituent materials of glass, plastic, metal and phosphor powder. The highest value PCB component in some CFLs will also be recovered. The project provided a relatively low cost, low throughput technology for the recovery of mercury from the phosphor powder, enabling the mercury to be recovered and the resultant non-hazardous powder to be reused. The powder contains several valuable rare earth metals – this process will better and more cost effectively prepare these powders for sale to recovery facilities in Europe, and enable a higher price to be paid to the SMEs.
The major advantage of this approach is to enable the lamp recycling industry to manage all materials on the production site and minimise transport to specialist mercury recovery facilities. The impact of this more cost effective approach to lamp recovery is likely to enable smaller regional facilities to become cost effective in Europe, to replace the vast logistics need that currently operates in transporting lamps to remote recycling facilities.
The Need for the SMEs and Research Co-ordination
It is of utmost importance that new competent organisations outside of the “established” recycling business are consulted to bring in their ideas, experience, expertise, and to help develop these new processes. The Project Team chosen has a proven track record in development of novel techniques from one area of technology, and enabling its beneficial use for different applications. The CFL recycling industry is dominated by SMEs who, although highly innovative, lack the internal resources to fund the required research themselves.
MRT has a long established record in provision of high quality processing equipment to recover end of life lamps. A barrier to sales in the recovery of mercury from powder has been the high cost of the technology even though the mercury content within the powder is relatively low. MRT would welcome external assistance in establishing a more cost effective technology to be developed to provide to its customers. MRT also need the technology input of the RTD partners to understand and optimise the operational parameters of a mercury removal system for this application; this work will benefit both development of a microwave system and potentially enhance operation of existing equipment.
WISER Recycling is the only UK lamp recycler to produce high quality glass cullet from TL lamps which is returned for remanufacture of lamps. The company has been working to provide the same level of quality from its CFL treatment process, but needs external resources and knowledge. The focus is to develop the techniques and equipment to improve its pre-crushing process, and trial a number of novel technologies to determine the most cost effective means of separating plastic and metal which can be scaled down for the CFL recovery requirements. DISMECO is facing similar challenges to WISER and likewise needs access to external research effort to deliver the process innovation required to produce high value recycled components. A successful project would enable WISER and DISMECO to be more efficient and cost effective in the recycling of CFL, increase the quality of the constituent materials from CFL, and increase revenues as a result. There is a rapidly increasing value and demand for rare earth materials, a component of the phosphor powders which currently are landfilled.
The general principle used in current equipment for mercury recovery from lighting products (phosphor, glass etc) is conventional heating often combined with reduced pressure. This is not an energy-efficient method and although mercury levels of 1-2 ppm are achievable in the recovered material this comes at far too high a price for small industrial production lines. There are wet chemistry methods involving washing of the material fractions with different liquids but this method requires treatment of the used chemicals and drying of material fractions. Distillation methods are viable for rare earth materials but a much more cost effective methodology is required for the glass and plastic fractions. Current high cost Hg removal processes require an inert atmosphere to stop the formation of oxides and therefore allow a reduced processing temperature.
The RELIGHT project has developed an energy-efficient heating method avoiding wet chemistry. This new method aims to significantly reduce operation cost for a recycling plant and will not create additional waste streams (in contrast to a wet chemistry method). SAIREM are a world leader in the provision of MW generators and led the decontamination work in the RELIGHT project.
Innovative character in relation to state-of-the-art
The CFL recycling technology to be developed in the project aims at achieving the following targets:
- Separation of CFL into glass, phosphor powder, plastics, printed circuit boards and metal parts with the materials having the following maximum content of contamination
i) Glass: mercury content <1-2ppm; plastic content <200 ppm; metal content <20 ppm
ii) Phosphor powder: mercury content <1-2 ppm
iii) Plastics: mercury content <1-2 ppm; glass content <1%
iv) Printed circuit boards: mercury content <1-2 ppm
v) Metal parts: mercury content <1-2 ppm
- Treatment capacity of 300 kg/h
- No wet chemistry involved (or only small amounts of liquids required)
- Affordable processing line, anticipated target pricing of maximum 350 000 Euro
- Continuous, automated process (less mercury exposure for operatives)
- Flexible (modular), compact, closed system that can be integrated into existing processes
These parameters will be further investigated and confirmed within WP1.
If “clean” material fractions (according to specifications above) can be obtained from waste CFLs, then the materials are of interest for re-use (instead of land-filling and low value recycling options such as use in aggregate) and will consequently have a higher value.
The key process steps to be addressed in the project are:
- Separation step 1 should be more effective in separating glass from E-base, reduce glass/plastic cross-contamination to <200 ppm and eliminate the need for additional down-stream separation steps of glass and plastics. Current separation technologies are only applicable to large scale operations and are therefore unsuitable for the small-scale SME processors who comprise the majority of CFL recyclers. RELIGHT aims to provide a cost-effective route for these small-scale operations.
- Separation step 3a-b will utilise a microwave process to remove mercury from phosphor powder and glass down to concentrations of 1-2 ppm. Previous work highlights that removal of mercury from CFLs is considerably more challenging than from other systems (cCFLs).
- Separation step 4 should be able to separate plastics, printed circuit boards and metal parts to such an extent that obtained fractions are clean and will constitute a value for materials recycling thus making the process profitable.
The main innovative steps to be employed and evaluated in the development of the process steps are:
- Separation step 1; current crusher technology will be developed to achieve a more accurate separation of the glass part from the E-base, reducing cross-contamination. By developing a new crusher set-up with blade patterns/design that in a more controlled manner separates the E-base from the glass, plastic contamination of the glass fraction and vice versa will be reduced. Potential means of identifying, orienting and more accurately removing the glass part from the E-base will be considered and evaluated for different types of CFLs. In addition, integrated solutions comprising separation principles other than mechanically sieving the materials will be evaluated.
- Separation step 3a-b; currently available cost effective heating methods to remove mercury are not feasible for reaching mercury content of 1-2 ppm in the recovered material fractions. An attractive candidate technology to be developed and evaluated in the project is microwave heating, which should be faster and more energy-efficient than currently used heating methods. As a volumetric heating method, microwave will rapidly heat throughout the waste stream rather than relying on slow heat transfer processes. Good design of the microwave system will also ensure that heating uniformity is achieved to provide a high level of mercury decontamination. This innovative approach has considerable potential to provide a new high throughput, continuous decontamination methodology. Work carried out by Sairem has shown microwave to be a highly effective mechanism for rapid and energy efficient heating of glass in other applications. However, in our state-of-the-art review, we have not found any information about microwave heating being used for removing mercury from other materials.
- Separation step 4; to our knowledge, there is currently no economically viable process in use for E-base separation. The project intended to modify and combine a range of technologies to separate the major parts - printed circuit board, plastic and metal parts - of the E-base into relatively pure fractions without using shredding but somewhat more careful methods for the separation. Separation of parts in WEEE is usually done manually, but in this case, the intention and challenge is to develop equipment which can do this. The equipment intended to be developed and evaluated for this step involves a tuneable rolling mill which will be used to break open the E-base, releasing the printed circuit board and the metal parts from the plastic. A magnetic roll for separating printed circuit boards from the E-base will either be integrated in the breaking step or employed after the breaking step. Magnetic separation of printed circuit boards from E-base has been proven to work in earlier tests. The separation of other metal-containing parts from the plastic will be attempted by employing a tailor-made vibration table connected to the rolling mill set-up.
In RELIGHT the three separation steps were evaluated on a lab-scale and separation steps 3a-b and 4 were also built and evaluated as prototype equipment. Separation step 1 was tested on a larger scale by modifying existing equipment.
Project Results:
Before the RELIGHT project began the process steps were divided into 4 main areas. Schematically the target process can be described as in Figure 1. below.
1. Separation Step 1 : E-base and Glass
The objective of the work carried out in this step of the process was to develop a cost-effective process for small-scale recycling operations which provides enhanced separation of CFL e-bases from the glass fraction. The e-base would then feed into step 4 and the glass and phosphor would undergo a decontamination step.
Modification of Crusher Technology
The aim was to enhance separation of the glass and plastic E-base in the initial crusher stage. System design must be cost effective for use on the relatively small scales operated by SMEs such as WISER. Current MRT technology can provide separation with a cross-contamination of plastics in glass of 1-3% with a cost in the region of €100,000 for a 600kg/h system. This work will focus on both improving the achievable separation and producing a smaller and cheaper system.
WISER utilised a modified bottle crusher for its CFL pre-treatment. This achieved a cross-contamination of plastics in glass of 3-5%. The project aimed to make further modifications and assess the crusher set up and blade patterns/design to minimise plastic contamination, in parallel to the work above. Technologies to be evaluated included the use of different configurations of crushing blades with different types of lamps.
CTECH with WISER evaluated the current system used and noted the limitations with a view to improve the current system:
• While in operation the fan overheats to such an extent that the crushing operation must be stopped.
• The expensive carbon filters fitted to reduce mercury exposure have a very short lifetime due to the over power of the crusher fan.
A detailed campaign of CFD calculations were undertaken to model the airflow through the system. While this was being run CTECH and WISER also trialed another type of crusher which was seen to give a superior separation.
The Wiser Group hired an imploder from Crystalline, the machine is specifically designed to selectively shear glass and has been trailed as a method of cleanly separating the glass component of CFLs from the E-base components of the lamp. C-Tech has run a series of technical trials on the imploder to collate and analyse information to asses weather the equipment may be suitable in achieving the work package objectives.
Each run consisted of the system being fed with 6kg/min of bulbs- a typical mix consisted of CFLs, halogen lamps and incandescent lamps and was representative of a standard collection. The output was manually sieved at 8mm, 5mm and 2mm and the fractions composition analysed at a range of running conditions. The main parameters investigated were the speed at which the paddles turned and the setting of ‘gap size’. Once initial testing was complete larger scale runs were carried out using~23kg material at approximately double the feed time.
Tests showed that with the wide 10mm gap setting less copper hair was liberated from the transistor and that plastics in the E-base become heavily shredded so the F1 (+8mm) volume was small and a high percentage of plastic contaminated the fine glass fraction. A 5mm gap setting was best, producing fractions clearly separating plastic metal and glass components. The slow speed setting appears most effective and cleanly separated all glass from the E-base with minimal damage to the plastics. Mid speed setting gave good glass destruction but also is abrasive to the plastics causing smaller pieces. The high speed setting creates too many glass fines and the plastic pieces are also small. Large scale sieving on a vibrating bed showed that the glass can be separated from the plastic and metal components at any of these settings but the mild settings (low speed 5mm gap) are deemed the most successful for the objective of the system as they produce the least fine glass. Fines are a problem for the next processing step of decontamination. The decontamination works using a cyclone to extract the Hg containing phosphor powders but if there is a high percentage of glass fines they too are extracted by this system and expelled into the phosphor waste. If the percentage of glass in the phosphor waste is too great then the buyer of this product is no longer interested and Wiser would have to pay to dispose of the toxic material.
Further scaled up trials were held using the industrial sieve equipment with hole sizes of 20mm and below. Initial trials resulted in e-bases settling within the holes and quickly blocking the sieve. The sieve bed was replaced with a 19mm punched hole sieve which enable the e-bases to process over the bed for collection and separation.
As a result the CFL process line was set up with additions of a feed conveyor to more efficiently and effectively introduce CFLs from ground level to the imploder, a conveyor to feed imploded materials to the vibrating sieve, and a ventilation/air extraction line to enable treatment of any diffuse mercury emission through a carbon filter.
The imploder line (figure 2) has enabled a throughput of approximately 200 kg per hour of CFL. The CFL are hand fed from bags and boxes used for collections from the producer, directly onto the feed conveyor where any contraries can be identified and removed prior to introduction to the imploder. The imploder blade and velocity are set, following initial trials, at levels to optimise breakage of glass from the e-base whilst minimising destruction of the plastics within the e-base. This enables the sieving mechanism to work by simple separation of size fractions, where the vast majority of the e-base is intact and does not pass through the 19mm sieve bed.
During initial trial runs of the equipment it was found that some destruction of the e-base was unavoidable and resulted in about 10% contamination of the glass fraction with plastics. Further hand sieve trials were conducted using 8mm and 6mm size apertures to remove plastics. A 6mm sieve was found to undertake the most effective separation and a further sieve bed of 6mm was added to the industrial sieve equipment.
The resultant glass fraction of <6mm was able to be directly introduced to the Compact Crush and Sieve (CCS) lamp treatment line, resulting in a higher quality glass material without significant plastics contamination, making sale for after use easier and with higher value potential.
Conclusions
• The imploder can very effectively shears the glass section from the E-base.
• The settings vary the degree to which the E-base is destroyed- faster speeds and a larger gap causes more destruction to plastics, and liberates copper hair.
• Reprocessing of the plastics and metals through the imploader once the glass has been sheared off at mild settings liberates metals that can be recycled or sold.
• Sieving is the key and a must be a follow on step from the imploder.
2. Separation Step 2 : Phosphor and Glass
This step was not looked at during the project – Wiser and Dismeco already own a CCS machine produced by MRT. This machine already separated the glass from the phosphor powder to an acceptable standard.
3. Separation Step 3 : Mercury Decontamination
The general principle used in current equipment for mercury recovery from lighting products (phosphor, glass etc) is conventional heating often combined with reduced pressure. This is not an energy-efficient method and although mercury levels of 1-2 ppm are achievable in the recovered material this comes at far too high a price for small industrial production lines. There are wet chemistry methods involving washing of the material fractions with different liquids but this method requires treatment of the used chemicals and drying of material fractions. Distillation methods are viable for rare earth materials but a much more cost effective methodology is required for the glass and plastic fractions. The current process conditions used to decontaminate a variety of CFL derived waste streams require high temperatures and long process times. Current high cost Hg removal processes require an inert atmosphere to stop the formation of oxides and therefore allow a reduced processing temperature.
The RELIGHT project aimed at developing an energy-efficient heating method avoiding wet chemistry. This new method aims to significantly reduce operation cost for a recycling plant and will not create additional waste streams (in contrast to a wet chemistry method).
The purpose of the proposed bench scale microwave equipment was to raise the temperature of glass waste and phosphor powder, both contaminated with mercury, from ambient temperatures to 200 – 500 ° C and thereby vaporize the mercury which will be driven off and collected outside the microwave cavity using appropriate condensers and filters.
Once designed, built and functionally tested, the microwave unit will be trialled at the premises of one of the project partners, WISER. The objectives of the trials was to:
• Determine the effectiveness of the microwave heating in driving off the mercury;
• Establish the characteristics of the process;
• Provide design data for future industrial scale units
• Identify any issues related to the microwave heating which may influence the design of industrial units.
The proposed bench scale unit will be batch and based on a 6 kW, 2450 MHz microwave power supply: this specification is due to the handling and availability of the raw material and the availability of a microwave power supply. Auxiliary heating for the surface of the drum was provided by infra-red elements mounted on the walls of the cavity.
The process envisaged two possible material streams for mercury decontamination by dielectric heating with electromagnetic energy:
• Crushed glass, requiring a final mercury content of 2 ppm;
• Phosphor powder, requiring a final mercury content of either ≤ 2 ppm or ≤ 50 ppm depending on the intended final use of the “decontaminated” phosphor.
The target parameters for a future industrial unit are shown in figure 3:
It was assumed that the waste in each case is largely free of plastic material. Separation of the various component materials is a task within work package WP2.
This task was carried out across both periods and the summary graphs are shown below
• Microwave decontamination of glass (figure 4)
The mercury content of the samples was obtained using standard techniques employing acid digestion and atomic absorption methods.
It can be seen in the figure above that 1 ppm mercury is achieved at temperatures ~ 250 – 350 ºC, the target level was achieved.
• Microwave decontamination of a phosphor/glass mix (~ 40% glass by weight, figure 5)
It is seen that the remaining mercury content plateau’s at around 15 ppm for temperatures of 250 – 450 ºC. While the upper target, < 50 ppm, was achieved the lower target was not (~1 ppm). In comparison with the contaminated glass, it is to be expected that the mercury on the contaminated phosphor will be more tightly bound and so should require higher temperatures.
In any case, these are encouraging, preliminary results for the glass and the phosphor/glass mix, using a relatively crude set up, these results were transferred from the lab scale to the pilot scale.
Development of System Design
The rationale of this project is that the volumetric heating characteristic of dielectric heating offers a number of significant process advantages. In developing the concept, the key areas for consideration were:
• The ability of the material to absorb electromagnetic energy;
• Can electromagnetic heating be used to remove mercury from the glass and phosphor waste produced in the treatment of fluorescent bulbs;
• Is the heating inherently uniform or non-uniform and if the latter how can any shortcomings this may produce be overcome;
• What is the potential efficiency of the process in terms of transfer of microwave energy to the product and the overall energy requirements of the heating process;
• Looking forward, what implications do the above have for the design of the bench scale unit and future industrial units?
The conclusions drawn from the work are:
• Glass is a poor to medium absorber of electromagnetic energy at radio and microwave frequencies but the absorption is adequate for present purposes;
• Absorption increases with increasing temperature, an undesirable effect when combined with possible non- uniform heating;
• Small scale, preliminary tests have achieved mercury decontamination of glass and a glass /phosphor mix down to levels of 1 ppm for the glass and ~15 ppm for the glass/phosphor mix;
• The benefit of volumetric heating can be exploited but the process will be easier to control and non-uniform heating easier to manage the smaller the power density; preliminary tests suggest < 0.5 kW per kg of glass;
• The dielectric properties of glass are similar at radio frequency and microwave frequencies and consequently microwaves are preferred since the electric fields required will be ten times smaller and arcing will be less likely;
• The benefit of a more uniform electric field distribution at radio frequencies cannot be exploited because non-uniform heating arises principally due to the non-homogeneity of the glass bed;
• Efficient transfer of microwave energy from the microwave generator to the glass, glass/phosphor waste should be possible at an industrial scale;
• Infra red heating does not provide the benefit of volumetric heating and is not as fast as dielectric heating; however it is relatively simple and may worthy of consideration as a means of augmenting the microwave heating if required;
• Estimates of the installed energy requirements and cost of the microwave generators has been made; the higher added value and smaller energy requirement for decontamination of phosphor/glass mixes may offer a low risk entry point for initial exploitation.
• The key challenge was seen to be the uniform heating of the glass bed: the glass bed needs to be well-mixed so that all glass pieces have a similar heating profile and adjacent pieces are in constant relative motion to avoid overheating and fusing of glass at points of contact.
With all these considerations taken on board the following unit was designed and built by the team at CTECH:
An outline drawing is shown in figure 6.
For the decontamination tests the pilot rig drum (figure 7) was used with the following procedure:
• The pilot rig drum was charged with a 5 - 7.5kg sample of Hg contaminated glass;
• The sample was then subjected to microwave heating in the pilot microwave cavity for periods of 50 - 100 minutes;
• After each heating period (100oC incremental rises), approximately 9g of the glass would be collected for analysis and the temperature recorded - measured in the glass bed by door mounted pyrometer:
The above trials were repeated to confirm results – this result is very positive showing the use of MW energy to remove mercury from glass (figure 8). The temperatures reached are much lower than first expected. This points to a level of selective mercury heating in the glass as it is expected that a temperature of approximately 320degC would be required in the glass to remove mercury.
Decontamination trials with WISER CFL phosphor
For the decontamination tests the pilot rig table (see below) was used with the following procedure:
• The pilot rig table was installed and a ceramic sager charged with a 7.5kg sample of Hg contaminated phosphor;
• The sample was then subjected to microwave heating in the pilot microwave cavity for periods of 50 - 100 minutes;
• After each heating period (50oC incremental rises), approximately 9g of the phosphor powder would be collected for analysis and the temperature recorded - measured in the phosphor bed by door mounted pyrometer (during sampling manual temp measurements were taken and it was seen that there was little difference in temperature profile across the large sample):
Results achieved are excellent – temperature required is well below 200oC to remove the majority of mercury (figure 9). The process time of 2 hours is well below that of current industrial distillation (8-24 hours) using standard heating processes. An increase in temperature will certainly reduce the mercury content (seen on smaller scale) below the 18ppm reached. During sampling the temperature profile was monitored (depth and width) and it was seen that a variance of only 5oC was seen in the depth – the hotter temperatures were seen at the base of the sagger. The sample size of 7.5Kg can be increased easily by using multiple saggers.
Conclusions and implications for future processing:
The rationale of this project was that the volumetric heating characteristic of dielectric heating offers a number of significant process advantages. With this volumetric heating advantage it is believed that this process could be expanded further to increase the volume to production volumes.
The conclusions drawn from the work are:
• The dielectric properties of glass are similar at radio frequency and microwave frequencies and consequently microwaves are preferred since the electric fields required will be ten times smaller and arcing will be less likely;
• The glass bed needs to be well-mixed so that all glass pieces have a similar heating profile and adjacent pieces are in constant relative motion to avoid overheating and fusing of glass at points of contact – this can be done in the pilot rig and uniform heating is observed.
• Efficient transfer of microwave energy from the microwave generator to the glass, glass/phosphor waste would be possible at an industrial scale;
• Infra-red heating does not provide the benefit of volumetric heating and is not as fast as dielectric heating; however it is relatively simple and is a valuable addition to the design to ‘kick start’ the heating profile;
• Microwave heating can decontaminate glass to a level below 1ppm – a level which may have to be reached if legislation is changed.
• Mercury is removed from the glass with temperatures as low as 200oC pointing the possibility of selective mercury heating.
• Microwave heating can decontaminate phosphor to a level below 20ppm
• Mercury is removed from the powder with temperatures as low as 160oC pointing the possibility of selective mercury heating.
4. Separation Step 4 : E-base
The objective of the work carried out in this step of the process was to develop a cost-effective process for small-scale recycling operations which provides enhanced separation of CFL e-bases and recover valuable components. Plastics, printed circuit boards and metal parts should be separated to such an extent that obtained fractions are clean and will constitute a value for materials recycling thus making the process profitable.
Material composition
The initial task was to clarify the material composition of CFLs in order to enable the operational processing parameters to be defined since the composition and variability of materials may influence the separation and purification processed being developed. End-of-life CFLs currently present in the waste stream, as well as new CFLs expected to be representative of the Italian, Swedish and UK waste streams in a 3 to 5 years time, were selected for analysis. The CFLs were from different applications (households and industrial lighting), from different manufacturers (Philips, Osram, GTG, etc.) and from the countries where the SMEs participating in the project are based (UK, Italy, Sweden) (Figure 10 and Figure 11). The CFLs were manually dismantled and the material fractions (glass, metal, plastics, printed circuit board, etc) were quantified (Figure 12 and Figure 13).
Inductively coupled plasma (ICP) analysis of the materials was conducted and showed value in metal parts from the electrode bases of CFLs having high concentrations of bronze and aluminium. Electrodes were also shown to contain bronze and electrode wires a mixture of copper, nickel and iron. Fourier transform infrared spectroscopy (FTIR) analysis of plastic parts showed some of them were made of pure polybutylene terephtalate (PBT) and others of polybutylene terephtalate with a Mg silicate filler. In two cases additional amine and carbonyl groups were also detected.
Regarding the higher value metal fraction, it was found that the printed circuit board (PCB) represents a significant weight-% of the e-base in CFLs used in consumer and household (figure 14).
The electrical transformers present on the PCBs (figure 15) have a high copper content, which makes these components particularly interesting for copper recycling with the potential of being an economically viable process due to the high value of copper as a scrap metal. Therefore, copper-containing components on the PCBs were quantified in more details. The components of interest were transformer coils, plastic coated coils, and ring coils (figure 16). The plastic coated coils were primarily of two frequently occurring sizes with a copper content of about 0.4 and 0.9 grams, respectively. An average weight of the copper was calculated to be 0.7 grams per coil. The ring coils showed the lowest mass of copper of about 0.1-0.2 gram per coil.
Separation of e-base components
Crushing and magnetic separation technologies were identified as the most suitable methods to deliver separation of e-base components and to recover the material fractions (polymer, metals, PCBs) contained within the e-bases of CFLs.
A prototype for e-base separation was designed, built and tested. The e-bases are manually loaded in the vibration feeder that feeds the e-bases into the roller crusher unit that crushes the e-bases into a mixed fraction (figure 17) that can be subsequently separated into magnetic and non-magnetic fractions by using an overband magnet (figure 18). The roller crusher consists of two cylindrical rollers mounted in opposite pairs with an adjustable gap. The rollers were custom-designed and built with a pattern that optimizes the breaking of the plastic housing of the e-bases while not crushing the PCBs. The construction of the roller mill enables to modify the roller gap and rotation speed, which enables to optimize the output fractions depending on the e-base fraction being fed into the e-base separator. The plastic housing is sufficiently crushed to have most of the plastic material ending up in the non-magnetic fraction, while only a minor amount of PCB pieces and other metal residues end up in the non-magnetic fraction. The crushed e-bases land on the conveyor belt which transports the material to the overband magnet installed above and across the conveyor belt. Separated ferrous materials are continuously removed by the recirculating belt. The separated magnetic fraction is released out of the first outlet on the side of the separator, while non-magnetic materials remain on the conveyor belt and comes out of the second outlet on the front of the separator. Figure 19 shows a typical input feed (e-bases), roller crushed e-bases at the intermediate stage prior to magnetic separation, and outlet materials (magnetic and non-magnetic fractions).
This approach optimizes the separation of the high-value copper from the low-value plastics of the e-base housings and PCBs. The combined use of a roller crusher and a separation magnet resulted in an increase of the copper content from about 5% in the original e-base fraction up to about 10% in the magnetically separated material fraction.
Scaled-up e-base separation equipment and assessment in an industrial environment
A scaled-up separation equipment for use in demonstration trials was built to process approximately 300 kg/h in line with the processing requirements that were identified as relevant to small-scale recycling companies (figure 20). For the trials in an industrial environment, the e-base separation unit was then transferred to DISMECO and installed at the company’s WEEE pre-processing plant in Bologna (figure 21), where DISMECO can operate the separation equipment within their own processing lines and adapting the processes for the requirements of different inputs.
The separator is designed for easy and continuous operations and all the components are integrated into a single unit with a small footprint of 3.5 m2 for space saving at a recycling plant (figure 22). The assessment trials of the up-scaled e-base separation equipment have shown successful results in separating the e-bases into a metal-rich magnetic fraction and a plastic-rich non-magnetic fraction (Figure 23). During this initial assessment of the equipment, the CFL e-bases were manually fed into the e-base separator through a vibration feeder (Figure 24). In order to maximize the volumes of e-bases being processed and to reduce the need of manual labor and thus operation cost, a conveyor belts has been designed by DISMECO and it is expected to be delivered and installed by the end of December 2014 for full operational assessment of the process line during 2015. The additional conveyor belt will enable the continuous feeding of the e-bases from the Auger screw crusher directly into the e-base separator (Figure 25), which will enable DISMECO to handle large volumes of CFL’s e-bases and recover the components in an efficient and in an industrial scale.
Potential Impact:
• Potential Impact
o Economic Impacts for SMEs
The technology has clear market potential and will have a strong impact on the economic prospects of the participants via two routes:
• The SME participants will use the technology directly in their own manufacturing operations and/or directly in the services they provide.
• MRT will manufacture and market process equipment and complete process lines based on the technology. The overall market introduction will possibly be deliberately delayed on the national markets of the participating recycler SMEs (WISER and DISMECO) to allow them an exclusive use of the high-efficiency processes developed in the project, thus strengthening their competitiveness on their domestic markets. The component/equipment supplier SME (SAIREM) will supply microwave equipment/components (if MW units are required) to the processing lines manufactured by MRT. The IPR agreement between the SMEs will govern any licensing matters related to the sales of equipment developed within the project.
With a target sales price of €300-350k per process line, the initial European market potential would be 15-20 million Euro, which is substantial for the technical coordinating SME, which presently has an annual turnover of €4 million. The initial market potential for sales outside EU is €80-85 million. Taking into account that the technology or parts of it can be applied for recycling LED light sources, the market potential may be considerably higher. Mercury decontamination methodologies may be equally applicable to a range of other market sectors including: mining wastes, contaminated soils, batteries, catalysts. The material separation equipment developed is expected to be applicable across the WEEE waste market sector.
The participants represent different parts of the value chain, as shown in Figure 26.
• The technical coordinating SME (MRT) will manufacture and supply recycling equipment based on the technology developed in the project. As the equipment is expected to meet specifications that no other currently existing equipment can match, MRT will be able to dramatically strengthen its position on the global market. This represents an estimated increase in turnover of 100-300% over five years following market introduction and a need to increase staff by 20-30 persons. MRT normally builds small series of processing lines (custom-made) and larger volumes would enable a more efficient manufacturing process, lowering the manufacturing costs by 20-25%, thus increasing margins. The generated knowledge and established network within the project group will help MRT boosting their future product development and sales, securing a strong market and technology position.
• The supplier of key components (SAIREM) for the recycling process equipment will benefit from the project since it will a) open new application areas for their products, b) increase their sales of components/equipment and c) establish a strong customer-supplier relationship with MRT and the recycler SMEs. If the initial European market potential of a processing line is €15-20 Million, the initial potential for SAIREM would be €1.5-3 Million within 4 years of project completion. The inovative technologies developed may also open up market opportunities across other sectors; for example optimised microwave systems for glass heating in a range of applications.
• The recycler SMEs (WISER and DISMECO) will be test pilots and early adopters of the recycling equipment developed. This will enhance their operations, providing increased volumes and quality of recycled, sellable materials and increased capacity at lower operation cost. This best practice process will enable them to match the WEEE directive requirements (and expected future requirements) for recycling rates. This will increase their competitiveness and help/allow them to obtain larger volumes for treatment. The recycler SMEs estimate that they can increase volumes of waste treated by 400% and increase recycling rates for CFLs to over 90%. More importantly this will move the material to a higher value, lower carbon footprint recycling outlet and increase revenues from sold recycled materials from a current loss of Euro 30 per tonne to an income of Euro 40-100 per tonne. Furthermore operation costs will be reduced by 50%, thus increasing margins significantly. The recyclers would in turn need to increase their number of employees by 50% as the increase in volume requires further resource. The established network within the project group will enable them access to best practice technology and know-how to secure their future competitiveness as WEEE recyclers. Both recycler SMEs anticipate that utilisation of the RELIGHT technology, incorporating both the increased value of recycled materials and enhanced throughput which the technology will enable, will contribute an annual value to their businesses in excess of €100K. After project completion, WISER will continue to host the scaled-up demonstrator system; providing them with instant capability to exploit the new techniques developed.
A techno-economic assessment of the two main methods which were developed for processing and refining the CFLs during the Relight project was carried out. This analysis was done by defining the probable investment and operational costs, which together with expected value of the refined products, allowed for return of investment (ROI) and net present value (NPV) calculations for different scenarios. It should be clarified that the techno-economic assessment does not take into consideration any regulatory demands, but only calculates on the economic benefits of using the new technical equipment that have been developed.
The two main units that have been built are a e-base separator (which separates the e-bases into PCB-rich fraction and plastic-rich fraction), and a microwave (MW) mercury removal demonstrator (which by MW heating evaporates and removes mercury from phosphor powder and the CFL glass).
Calculations were made for MW treatment of phosphor powder which contains high mercury contamination levels of around 1000 ppm (parts per million). The phosphor powder contains oxides of rare earth elements which could be highly valuable. During the CFL recycling however the phosphor powder will inevitably be mixed with crushed glass. Decreasing the mercury contamination will increase the value of the phosphor powder even though it contains glass impurities but far from its pure form. The trials using the MW mercury removal demonstrator shows that while using less energy than conventional methods the ppm level of phosphor powder is decreased within reasonable time down to around 15 ppm. At such ppm levels however the ROI and NPV calculations show little economic incentive at the moment to invest in such equipment. However at higher phosphor powder volumes sold at higher prices there could be economic gains with investing in MW treating equipment that could outweigh the economic risks. More specific, phosphor powder volumes of around and above 150 tonne per year at post treatment prices of around or above 750 €/tonne, which could be achieved if the mercury ppm level is decreased further below 5 ppm, could motivate investment in MW removal equipment.
The glass in CFLs are of different quality and composition, and the decrease of the mercury contamination from around 10 ppm to below 1 ppm does not increase substantially the avenues to sell the glass at higher prices. Therefore little economic incentive was seen in treating the glass fraction to remove the mercury.
Calculations show that the economics of the e-base separator is more viable. Especially for the less labour demanding setup of feeding the e-base separator directly with the e-bases that are separated from the glass and phosphor powder of the CFLs. The calculated ROIs are for such automatic setup between 3.2 and 1.4 years at the expected investment cost, operational cost and profits. The NPV value is also at 10 years end (economic life time) somewhere between €250 000 - €400 000, depending on the discount rate, comparing to €150 000 for if the e-bases are sold unprocessed.
o Effect on Competitiveness on SMEs
Recycling companies WISER and DISMECO will be early adopters of the new technology and will gain a competitive advantage by employing this technology which will provide a step-change improvement in separation and decontamination compared to currently existing technologies. As existing recyclers with established sites and customers they are in an excellent position to be able to exploit the technology. Both companies are technically innovative SMEs who are capable and willing to adopt novel technologies. Adopting the RELIGHT technology will enable them to expand operations and the increasing market volumes of CFL should ensure that this expansion is an excellent fit to broader market needs. WISER currently operates a closed-loop recycling system for fluorescent tubes and would therefore be in a strong position to apply this approach to the CFLs processed by the RELIGHT project. Separated products obtained (e.g. glass) could be sold to their existing customers at an enhanced margin due to the higher levels of purity obtained. As stated previously, the geographic differentiation between these two recycling companies means that they are not directly competitive.
A successful project outcome from the perspective of CFL recycling SMEs WISER and DISMECO will be to:
• Fully separate glass and e-base of the CFL to increase productivity.
• Fully separate constituent materials of the e-base to enable an increased income of approximately €100 to €230 per tonne.
• Increase glass quality and make fit for reuse in a manufacturing process a net increase in income of €20 per tonne
• Reduce costs of mercury removal from phosphor powders by up to euro 800 per tonne.
• Enable phosphors to be in a state suitable for sale to reprocessors to directly recover rare earths – potential value of €2000 per tonne and increasing.
Processes developed within the project should be possible to apply for the efficient recycling of other products containing mercury. New application markets, which require enhanced recovery of mercury from different materials, will be assessed within the project. The technology and knowledge generated in the project will be considered and tested for use recycling of CCFLs, a common light source in liquid crystal display monitors.
One part of the development work, will be to consider the requirements and potential for applying the processes for recycling to the expected future major lighting source, light-emitting diodes (LED). The LED market is expected to grow rapidly, from 5.1 billion USD in 2008 to 16.5 billion USD in 2013, and there will be a strong future need for recycling technology suitable for LEDs.
o Economic Justification of the Research
It is our strong belief and goal that the expected total project cost of €1.24 Million will generate significantly increased revenues to the participating SMEs over a four-year period following the completion of the project. To achieve this, the participating SMEs will have to employ a number of extra persons over the same period of time. Exploitation in other markets and wider geographical uptake mean the long term revenue prospects of all SME partners will be greatly enhanced.
After completion of the project, the goal is to install CFL processing lines at the operation sites of the recycler SMEs for full-scale long-term testing. In parallel, the design of the processing line will be fine-tuned and the manufacturing procedure for the equipment will be further optimized by MRT in collaboration with the component supplier SAIREM. This phase will take 6-12 months before a real market introduction can be made. At market introduction, the installed lines at DISMECO and WISER may serve as reference/demonstration lines both for customers of MRT and customers of the recycler SMEs. The second year after the completion of the project, MRT expects to be able to sell 5-10 CFL processing lines, the third and fourth year 10-20 processing lines per year. The expected impact of a successful project in terms of increased revenues for the SMEs is shown in Figure 27.
At present the partners have no equipment to remove mercury from phosphor and distillation of mercury from the phosphor powder is undertaken by a third party. This is at a cost of nearly £1,000 per tonne. Existing equipment is cost prohibitive with the volumes of lamps that partners currently recycle. A more cost effective means of removing mercury from the phosphor powders will provide an opportunity to market the resultant powders, provide more flexibility in the outlets available, and increase value due to supply and demand. In addition it is not currently feasible for that equipment to remove any residual mercury attached to glass/metal/plastics products. Should there be a need to further process these materials, an alternative continuous flow process that is more cost effective would potentially save many thousands of pounds and process time. The CFL processing site will produce high quality glass cullet resulting in an income of €25 per tonne for the glass rather than the current net cost of -€30 per tonne for aggregate recycling. To clean up the plastics and enable higher quality materials for recycling will increase the value by about €230 per tonne. For an annual tonnage equivalent to WISERs current operations of 100 tonnes per year, this provides a net increase in value of €25,000. The expectation is that CFL tonnages, driven by the rapid increase in usage, will increase 4 fold over the next 3 years. This will therefore provide an annual economic benefit to the SME recycler partners of approximately €100,000. Additional value could be obtained from sale of decontaminated phosphor powder for recovery of rare earth metals. The current throughput of mercury containing lamps is 1,000 tonnes per year with phosphor content (€2,500 per tonne) of 4% the potential annual saving is €41,000. An increased quality of phosphor for sale purpose has the ability to earn revenues of €104,000.
o Contribution Towards Community Societal Objectives
The project aims at developing a process line for handling and recycling discarded CFLs. The global production of CFLs worldwide was close to 3 billion units in 200625. The volume of CFLs appearing in the European waste stream is expected to be 2.5-3 billion units (approximately 500 000 tonnes) over the period 2011-2018.
The process to be developed will;
- Achieve the present and expected future recycling rates of the WEEE directive, enabling an increase in recycling rate from 40-50 weight% (currently) to over 90 weight% in the plants applying the technology. Over the time period 2011-2018 this would represent an increase in European recycled CFL material volumes of more than 200 000 tonnes. This corresponds to a considerable reduction in CO2 emissions due to a more efficient use of resources.
- Handle relatively small waste volumes cost-efficiently, enabling distributed recycling of CFLs and reducing the need and environmental impact of waste transportation.
- Ensure that the recyclers can deliver 50% more cost-efficient services and that the obtained material fractions are of high value and attractive for re-use leading to higher income for the recyclers.
- Exhibit performance and cost characteristics that will be superior to existing technology for small and medium-scale recycling plants. There is presently no technology/equipment which is suitable for small-and-medium-scale recyclers. RELIGHT will develop processes and equipment optimized for handling CFLs, which will deliver purer, re-usable material fractions than current large-scale technology at one third of the investment cost.
As the process equipment should be affordable for distributed recycling, it will also be attractive for customers/users in Asia and Africa, opening a large market and at the same time contributing to increased recycling and more sustainable handling of discarded lighting products in these parts of the world. The annual global market potential for this type of process equipment is estimated at 100 Million Euro (about 300 lines) over the next 5-7 years. It should be pointed out that, MRT has identified a substantial market for their products also among the 4,000 lamp manufacturers in China where there is a need for recycling manufacturing waste.
Legislation & Regulation
The WEEE Directive requires that lamps are collected and recycled and that a recovery rate of 80% is achieved. The Directive is revised regularly, and it is apparent that the required recovery rates will increase with every revision. Currently, a proposed revision is under consideration stating a general increase of 5% in the recovery rates of WEEE. The legislation for handling hazardous substances, such as mercury, and associated emission limits are also expected to become stricter requiring industry to invest in more efficient process equipment. This will also lead to stricter requirements with regards to content of hazardous substances and purity on recycled materials to be approved for re-use.
For companies, be it recyclers or suppliers of recycling equipment, staying ahead of legislation by offering processes and operations that match the future requirements will inevitably provide a strong competitive edge, both on the European market and globally.
Cost Acceptance
As mentioned above, we aim at developing a processing line for small-to-medium-scale recycling being suitable for distributed recycling. It is imperative that such a product is affordable and enables a relatively short pay-back time. The target pricing of the line to be developed must not exceed €350,000 to receive cost acceptance, according to participating recycler SMEs and MRT’s market experience.
o Trans-national Approach
The WEEE directive states that the recycling rate for CFLs should be at least 80%. This is valid for all EU member states. In Europe, waste normally has to be handled in the country where it is generated. Thus, it is of European interest that rational and cost-effective waste handling and recycling technology is made available to operations in all EU member states. In the short term, the current project has the goal to lead to an industrial implementation of a better Best Practise for CFL recycling in UK and Italy. If successful, the technology will be implemented in other European countries and globally. The technology field is relatively narrow and will require the involvement of specialist competence and specialised companies spread over Europe. Moreover, the national markets for recycling equipment are limited in Europe. Thus, transnational collaboration and interaction are important for succeeding with the RELIGHT project. Many of the SMEs in the recycling industry have limited contact with research environments and in many cases the appropriate competence is not found in their own countries. RELIGHT has a large potential to serve as a starting point for increased interactions and development of an established European network for SMEs developing and using sustainable WEEE recycling technology.
MRT will take on a major role for commercialising the technology developed in the project in the form of lamp-recycling equipment to be marketed globally. SAIREM will commercialize microwave heat treatment equipment for recycling applications in collaboration with MRT which has the market insight. WISER and DISMECO will implement the technology in their operations being full-scale test sites for the equipment developed and manufactured by MRT/SAIREM.
MRT has already its major market outside Sweden and has established an efficient sales organisation throughout Europe, which will be used for introducing the process technology developed in RELIGHT on the European market. In order to maintain its competitiveness, MRT has identified the need for methods enabling >90% recycling rates, thus matching the future requirements of the WEEE directive for lighting products. The key for achieving this is to have methods that can separate materials into pure fractions with mercury content below 1 ppm. This would yield recycled materials of higher value and would increase the attractiveness and market price for re-use.
It is clear that the WEEE directive has forced the development of advanced recycling technology in Europe. Similar directives have been and are being implemented in Asia, creating a business opportunity for European suppliers of recycling equipment meeting the requirements of the new directives in Asia. However, pricing and cost-effectiveness is important in Asia, where most recycling plants are still relatively small compared to other industrial manufacturing plants. The RELIGHT project is targeting a method for small-to-medium-scale recycling plants yielding high-value materials and being cost-effective. If the project is successful, it will considerably strengthen the position for MRT in Asia and allow MRT/SAIREM to compete with emerging Asian suppliers of recycling equipment. It will also show the way for other European SMEs and recycling technologies.
o Potential impact from further research
After completion of the project, the onward research and development related to the technology will comprise the following steps:
• Evaluation of the CFL processing line at the operation sites of the recycler SMEs in full-scale long-term testing. The performance of the line will be evaluated in terms of capacity, robustness (availability), purity of obtained materials, mercury emissions, working environment and potential for cost reduction/margin increase. This phase will take 6-9 months.
• Based on the results, the line will be optimized and fine-tuned, during 3-6 months.
• The next generation of processing line will include process steps for recovering rare earth metals from the phosphor powder. Currently, cost-effective technology for recovering valuable materials, such as Europium and Yttrium, from phosphor powders is not readily available. This may be done in a separate project parallel to RELIGHT or as a natural continuation of RELIGHT. This would also include research for developing applications for recycled phosphor powders (free from mercury and rare earth metals). This step should only be incorporated if the value of recovered rare earth metals exceeds the processing cost.
• The importance of separating different types of plastics in the waste stream will increase continuously. In 3-4 years, the demand for recycled plastics (e.g. from WEEE) will be significant leading to augmented material prices. It is then expected to be feasible to incorporate a plastics separation step as a part of the E-base separation process. This may be adjusted to suit discarded lamps and the major plastics used therein.
An exploitation plan has been prepared during the project (initial version completed at month 6 and final version submitted at M24), reviewed regularly at project meetings and finalised prior to project completion to define and protect foreground intellectual property and know-how created. The plan focused on the most promising results matched with the most vibrant market opportunities.
Market acceptance has been established through close consultation with the customer. In WP5, the suitability of recovered components for high-value applications were evaluated with potential end-user companies and organisations to ensure effective product evaluation.
Exploitation and dissemination are extremely important activities within RELIGHT. The consortium partnership is eager to disseminate the results from this project as widely as possible and to maximise the commercial impact of the results and technologies developed during the project through a proactive and strategic exploitation plan.
However, the consortium is also aware that it must maintain confidentiality of its know-how and protect its IPR position in order to establish a strong position in such a competitive market. Therefore, although dissemination was pursued as quickly as possible, it will at all times be subordinate to the IPR protection – this will continue well beyond the end of the project. WP 7 was planned to specifically deal with Dissemination and Exploitation and the related issues of IP protection and Training (technology transfer).
A proactive exploitation strategy has been adopted to ensure that the economic, commercial and developmental impacts of the outputs from RELIGHT are maximised. The potential for exploitation of the technologies developed and the recycled products were continually evaluated as part of WP7. A detailed summary of all the dissemination activities can be found in the final report. Activities included talks at conferences and trade events to publications in national press and scientific journals.
List of Websites:
http://www.relightproject.eu/
The Waste Electrical and Electronic Equipment Directive (WEEE Directive) is the European Community directive 2002/96/EC on waste electrical and electronic equipment (WEEE) which became European Law in February 2003, setting collection, recycling and recovery targets for all types of electrical goods including lamps. The directive requires that lamps are collected and recycled and that a recovery rate of 80% is achieved. As incandescent lamps are being successively banned in the EU, the volume of Compact Fluorescent Lamps (CFLs) is increasing rapidly and to be able to meet the legislation, 80% of all CFLs need to be recycled and 80% of the lamp material needs to be reused/recycled.
The advantage of CFLs is the saving of energy during use compared to that of the filament lamp. However, at end of life the CFL is significantly more difficult to recycle, partly due to the presence of hazardous mercury within the lamp, but also due to the different materials of construction.
The aim of RELIGHT project has been to test and to develop novel technologies in the niche application of CFL recycling, to find a cost effective means of recovering high value materials from the product.
The outcomes of the project have determined the type, scale, set up and cost of process equipment that will turn a CFL lamp into clean, high value constituent materials of glass, plastic, metal and phosphor powder. A compact crusher has been developed to separate these component parts and prepare them for sale.
The project has also provided a relatively low cost, medium throughput technology for the recovery of mercury from the phosphor powder, enabling the mercury to be recovered and the resultant non-hazardous powder to be reused. The powder contains several valuable rare earth metals – this process will better and more cost effectively prepare these powders for sale to recovery facilities in Europe, and enable a higher price to be paid to the SMEs.
Project Context and Objectives:
There are recycling technologies available on the market already. Currently, two types of techniques are utilised for recycling of fluorescent lamps. One technique is known as "end cut", employing a process by which both ends of the fluorescent tube are removed before the materials are separated and processed to a high purity product. The other technique is known as "crush and sieve". It crushes the complete product, after which the various components are separated and processed. There are also existing technologies to remove mercury from fluorescent powder and other mercury contaminated material. However, there are currently no cost-effective methods allowing the recyclers to meet the stricter requirements for mercury content below 1-2ppm in materials for re-use.
These existing techniques will be able to handle the linear (TL) fluorescent lamps and separate into an acceptable level with clean, recyclable glass. CFLs will also be possible to be separated into clean, recyclable glass. However, current methods result in a contamination of between 1-5% plastic in the glass, which means that recycling to aggregate is the main viable outlet. To recycle to higher use end markets the glass needs to be less contaminated with plastic, with the overall aim of achieving closed loop recycling of CFL glass a realistic aim.
However, for CFLs the glass only represents ~50% of the material and will therefore not meet the requirement of 80% recycling level and further work is needed to increase the proportion and value of recovered materials.
The primary advantage of recycling CFLs today is diversion of mercury from landfill sites; the actual scrap value of the materials salvaged from a discarded lamp is insufficient to offset the cost of recycling. The target for small recyclers such as WISER and DISMECO is the development of cost effective, practical and environmental sound methods for recycling of compact fluorescent lamps. There are three main issues that need to be addressed in order to achieve the legislated recycling targets;
1. Separation of e-base (bulb base containing plastic and electronic components) into recyclable components.
2. Reduction of mercury in “clean fractions” from 5-10 ppm down to 1-2 ppm.
3. Reduction of mercury in fluorescent powder from 2000 ppm down to 1-2 ppm.
These processes need to be cost effective and self-financed by the scrap value of the materials salvage. This means that today’s known and available technologies could not be used. A lot of work has been done by MRT and others, scaling existing technical solutions to meet these requirements, but without success. To reach these targets, innovative new technologies and processes are required
Project Objectives in Improving Recovery Technology
The RELIGHT project has tested and developed novel technologies in the niche application of CFL recycling, to determine a cost effective means of recovering high value materials from the product.
To be able to meet the WEEE Directive requirements and handle the increasingly large volumes of hazardous CFL and other gas discharge lamp waste best practice in lamp recycling needs to be improved and made commercially plausible. If this is achieved, there is a huge global market potential. The number of End of Life Lamps (EOLs) will more than double in the nearest future and the collection levels will increase from 10-20% up to 80-90%. First on the market with a technically and commercially effective process will be able to take a large part of this volume and be able to solve a huge environmental problem.
There is not only a strong market force from RELIGHT SME participants point of view to achieve cleaner fractions; it is also a requirement of the legislation. It is the view of the participants that to achieve only recycling of lamps to low value outlets is not ambitious, and that the industry should be seeking to recover valuable materials back to a high value use. These issues are prerequisite for the lamp recycling industry.
The RELIGHT project outcomes determined the type, scale, set up and cost of process equipment that will turn a CFL lamp into clean, high value constituent materials of glass, plastic, metal and phosphor powder. The highest value PCB component in some CFLs will also be recovered. The project provided a relatively low cost, low throughput technology for the recovery of mercury from the phosphor powder, enabling the mercury to be recovered and the resultant non-hazardous powder to be reused. The powder contains several valuable rare earth metals – this process will better and more cost effectively prepare these powders for sale to recovery facilities in Europe, and enable a higher price to be paid to the SMEs.
The major advantage of this approach is to enable the lamp recycling industry to manage all materials on the production site and minimise transport to specialist mercury recovery facilities. The impact of this more cost effective approach to lamp recovery is likely to enable smaller regional facilities to become cost effective in Europe, to replace the vast logistics need that currently operates in transporting lamps to remote recycling facilities.
The Need for the SMEs and Research Co-ordination
It is of utmost importance that new competent organisations outside of the “established” recycling business are consulted to bring in their ideas, experience, expertise, and to help develop these new processes. The Project Team chosen has a proven track record in development of novel techniques from one area of technology, and enabling its beneficial use for different applications. The CFL recycling industry is dominated by SMEs who, although highly innovative, lack the internal resources to fund the required research themselves.
MRT has a long established record in provision of high quality processing equipment to recover end of life lamps. A barrier to sales in the recovery of mercury from powder has been the high cost of the technology even though the mercury content within the powder is relatively low. MRT would welcome external assistance in establishing a more cost effective technology to be developed to provide to its customers. MRT also need the technology input of the RTD partners to understand and optimise the operational parameters of a mercury removal system for this application; this work will benefit both development of a microwave system and potentially enhance operation of existing equipment.
WISER Recycling is the only UK lamp recycler to produce high quality glass cullet from TL lamps which is returned for remanufacture of lamps. The company has been working to provide the same level of quality from its CFL treatment process, but needs external resources and knowledge. The focus is to develop the techniques and equipment to improve its pre-crushing process, and trial a number of novel technologies to determine the most cost effective means of separating plastic and metal which can be scaled down for the CFL recovery requirements. DISMECO is facing similar challenges to WISER and likewise needs access to external research effort to deliver the process innovation required to produce high value recycled components. A successful project would enable WISER and DISMECO to be more efficient and cost effective in the recycling of CFL, increase the quality of the constituent materials from CFL, and increase revenues as a result. There is a rapidly increasing value and demand for rare earth materials, a component of the phosphor powders which currently are landfilled.
The general principle used in current equipment for mercury recovery from lighting products (phosphor, glass etc) is conventional heating often combined with reduced pressure. This is not an energy-efficient method and although mercury levels of 1-2 ppm are achievable in the recovered material this comes at far too high a price for small industrial production lines. There are wet chemistry methods involving washing of the material fractions with different liquids but this method requires treatment of the used chemicals and drying of material fractions. Distillation methods are viable for rare earth materials but a much more cost effective methodology is required for the glass and plastic fractions. Current high cost Hg removal processes require an inert atmosphere to stop the formation of oxides and therefore allow a reduced processing temperature.
The RELIGHT project has developed an energy-efficient heating method avoiding wet chemistry. This new method aims to significantly reduce operation cost for a recycling plant and will not create additional waste streams (in contrast to a wet chemistry method). SAIREM are a world leader in the provision of MW generators and led the decontamination work in the RELIGHT project.
Innovative character in relation to state-of-the-art
The CFL recycling technology to be developed in the project aims at achieving the following targets:
- Separation of CFL into glass, phosphor powder, plastics, printed circuit boards and metal parts with the materials having the following maximum content of contamination
i) Glass: mercury content <1-2ppm; plastic content <200 ppm; metal content <20 ppm
ii) Phosphor powder: mercury content <1-2 ppm
iii) Plastics: mercury content <1-2 ppm; glass content <1%
iv) Printed circuit boards: mercury content <1-2 ppm
v) Metal parts: mercury content <1-2 ppm
- Treatment capacity of 300 kg/h
- No wet chemistry involved (or only small amounts of liquids required)
- Affordable processing line, anticipated target pricing of maximum 350 000 Euro
- Continuous, automated process (less mercury exposure for operatives)
- Flexible (modular), compact, closed system that can be integrated into existing processes
These parameters will be further investigated and confirmed within WP1.
If “clean” material fractions (according to specifications above) can be obtained from waste CFLs, then the materials are of interest for re-use (instead of land-filling and low value recycling options such as use in aggregate) and will consequently have a higher value.
The key process steps to be addressed in the project are:
- Separation step 1 should be more effective in separating glass from E-base, reduce glass/plastic cross-contamination to <200 ppm and eliminate the need for additional down-stream separation steps of glass and plastics. Current separation technologies are only applicable to large scale operations and are therefore unsuitable for the small-scale SME processors who comprise the majority of CFL recyclers. RELIGHT aims to provide a cost-effective route for these small-scale operations.
- Separation step 3a-b will utilise a microwave process to remove mercury from phosphor powder and glass down to concentrations of 1-2 ppm. Previous work highlights that removal of mercury from CFLs is considerably more challenging than from other systems (cCFLs).
- Separation step 4 should be able to separate plastics, printed circuit boards and metal parts to such an extent that obtained fractions are clean and will constitute a value for materials recycling thus making the process profitable.
The main innovative steps to be employed and evaluated in the development of the process steps are:
- Separation step 1; current crusher technology will be developed to achieve a more accurate separation of the glass part from the E-base, reducing cross-contamination. By developing a new crusher set-up with blade patterns/design that in a more controlled manner separates the E-base from the glass, plastic contamination of the glass fraction and vice versa will be reduced. Potential means of identifying, orienting and more accurately removing the glass part from the E-base will be considered and evaluated for different types of CFLs. In addition, integrated solutions comprising separation principles other than mechanically sieving the materials will be evaluated.
- Separation step 3a-b; currently available cost effective heating methods to remove mercury are not feasible for reaching mercury content of 1-2 ppm in the recovered material fractions. An attractive candidate technology to be developed and evaluated in the project is microwave heating, which should be faster and more energy-efficient than currently used heating methods. As a volumetric heating method, microwave will rapidly heat throughout the waste stream rather than relying on slow heat transfer processes. Good design of the microwave system will also ensure that heating uniformity is achieved to provide a high level of mercury decontamination. This innovative approach has considerable potential to provide a new high throughput, continuous decontamination methodology. Work carried out by Sairem has shown microwave to be a highly effective mechanism for rapid and energy efficient heating of glass in other applications. However, in our state-of-the-art review, we have not found any information about microwave heating being used for removing mercury from other materials.
- Separation step 4; to our knowledge, there is currently no economically viable process in use for E-base separation. The project intended to modify and combine a range of technologies to separate the major parts - printed circuit board, plastic and metal parts - of the E-base into relatively pure fractions without using shredding but somewhat more careful methods for the separation. Separation of parts in WEEE is usually done manually, but in this case, the intention and challenge is to develop equipment which can do this. The equipment intended to be developed and evaluated for this step involves a tuneable rolling mill which will be used to break open the E-base, releasing the printed circuit board and the metal parts from the plastic. A magnetic roll for separating printed circuit boards from the E-base will either be integrated in the breaking step or employed after the breaking step. Magnetic separation of printed circuit boards from E-base has been proven to work in earlier tests. The separation of other metal-containing parts from the plastic will be attempted by employing a tailor-made vibration table connected to the rolling mill set-up.
In RELIGHT the three separation steps were evaluated on a lab-scale and separation steps 3a-b and 4 were also built and evaluated as prototype equipment. Separation step 1 was tested on a larger scale by modifying existing equipment.
Project Results:
Before the RELIGHT project began the process steps were divided into 4 main areas. Schematically the target process can be described as in Figure 1. below.
1. Separation Step 1 : E-base and Glass
The objective of the work carried out in this step of the process was to develop a cost-effective process for small-scale recycling operations which provides enhanced separation of CFL e-bases from the glass fraction. The e-base would then feed into step 4 and the glass and phosphor would undergo a decontamination step.
Modification of Crusher Technology
The aim was to enhance separation of the glass and plastic E-base in the initial crusher stage. System design must be cost effective for use on the relatively small scales operated by SMEs such as WISER. Current MRT technology can provide separation with a cross-contamination of plastics in glass of 1-3% with a cost in the region of €100,000 for a 600kg/h system. This work will focus on both improving the achievable separation and producing a smaller and cheaper system.
WISER utilised a modified bottle crusher for its CFL pre-treatment. This achieved a cross-contamination of plastics in glass of 3-5%. The project aimed to make further modifications and assess the crusher set up and blade patterns/design to minimise plastic contamination, in parallel to the work above. Technologies to be evaluated included the use of different configurations of crushing blades with different types of lamps.
CTECH with WISER evaluated the current system used and noted the limitations with a view to improve the current system:
• While in operation the fan overheats to such an extent that the crushing operation must be stopped.
• The expensive carbon filters fitted to reduce mercury exposure have a very short lifetime due to the over power of the crusher fan.
A detailed campaign of CFD calculations were undertaken to model the airflow through the system. While this was being run CTECH and WISER also trialed another type of crusher which was seen to give a superior separation.
The Wiser Group hired an imploder from Crystalline, the machine is specifically designed to selectively shear glass and has been trailed as a method of cleanly separating the glass component of CFLs from the E-base components of the lamp. C-Tech has run a series of technical trials on the imploder to collate and analyse information to asses weather the equipment may be suitable in achieving the work package objectives.
Each run consisted of the system being fed with 6kg/min of bulbs- a typical mix consisted of CFLs, halogen lamps and incandescent lamps and was representative of a standard collection. The output was manually sieved at 8mm, 5mm and 2mm and the fractions composition analysed at a range of running conditions. The main parameters investigated were the speed at which the paddles turned and the setting of ‘gap size’. Once initial testing was complete larger scale runs were carried out using~23kg material at approximately double the feed time.
Tests showed that with the wide 10mm gap setting less copper hair was liberated from the transistor and that plastics in the E-base become heavily shredded so the F1 (+8mm) volume was small and a high percentage of plastic contaminated the fine glass fraction. A 5mm gap setting was best, producing fractions clearly separating plastic metal and glass components. The slow speed setting appears most effective and cleanly separated all glass from the E-base with minimal damage to the plastics. Mid speed setting gave good glass destruction but also is abrasive to the plastics causing smaller pieces. The high speed setting creates too many glass fines and the plastic pieces are also small. Large scale sieving on a vibrating bed showed that the glass can be separated from the plastic and metal components at any of these settings but the mild settings (low speed 5mm gap) are deemed the most successful for the objective of the system as they produce the least fine glass. Fines are a problem for the next processing step of decontamination. The decontamination works using a cyclone to extract the Hg containing phosphor powders but if there is a high percentage of glass fines they too are extracted by this system and expelled into the phosphor waste. If the percentage of glass in the phosphor waste is too great then the buyer of this product is no longer interested and Wiser would have to pay to dispose of the toxic material.
Further scaled up trials were held using the industrial sieve equipment with hole sizes of 20mm and below. Initial trials resulted in e-bases settling within the holes and quickly blocking the sieve. The sieve bed was replaced with a 19mm punched hole sieve which enable the e-bases to process over the bed for collection and separation.
As a result the CFL process line was set up with additions of a feed conveyor to more efficiently and effectively introduce CFLs from ground level to the imploder, a conveyor to feed imploded materials to the vibrating sieve, and a ventilation/air extraction line to enable treatment of any diffuse mercury emission through a carbon filter.
The imploder line (figure 2) has enabled a throughput of approximately 200 kg per hour of CFL. The CFL are hand fed from bags and boxes used for collections from the producer, directly onto the feed conveyor where any contraries can be identified and removed prior to introduction to the imploder. The imploder blade and velocity are set, following initial trials, at levels to optimise breakage of glass from the e-base whilst minimising destruction of the plastics within the e-base. This enables the sieving mechanism to work by simple separation of size fractions, where the vast majority of the e-base is intact and does not pass through the 19mm sieve bed.
During initial trial runs of the equipment it was found that some destruction of the e-base was unavoidable and resulted in about 10% contamination of the glass fraction with plastics. Further hand sieve trials were conducted using 8mm and 6mm size apertures to remove plastics. A 6mm sieve was found to undertake the most effective separation and a further sieve bed of 6mm was added to the industrial sieve equipment.
The resultant glass fraction of <6mm was able to be directly introduced to the Compact Crush and Sieve (CCS) lamp treatment line, resulting in a higher quality glass material without significant plastics contamination, making sale for after use easier and with higher value potential.
Conclusions
• The imploder can very effectively shears the glass section from the E-base.
• The settings vary the degree to which the E-base is destroyed- faster speeds and a larger gap causes more destruction to plastics, and liberates copper hair.
• Reprocessing of the plastics and metals through the imploader once the glass has been sheared off at mild settings liberates metals that can be recycled or sold.
• Sieving is the key and a must be a follow on step from the imploder.
2. Separation Step 2 : Phosphor and Glass
This step was not looked at during the project – Wiser and Dismeco already own a CCS machine produced by MRT. This machine already separated the glass from the phosphor powder to an acceptable standard.
3. Separation Step 3 : Mercury Decontamination
The general principle used in current equipment for mercury recovery from lighting products (phosphor, glass etc) is conventional heating often combined with reduced pressure. This is not an energy-efficient method and although mercury levels of 1-2 ppm are achievable in the recovered material this comes at far too high a price for small industrial production lines. There are wet chemistry methods involving washing of the material fractions with different liquids but this method requires treatment of the used chemicals and drying of material fractions. Distillation methods are viable for rare earth materials but a much more cost effective methodology is required for the glass and plastic fractions. The current process conditions used to decontaminate a variety of CFL derived waste streams require high temperatures and long process times. Current high cost Hg removal processes require an inert atmosphere to stop the formation of oxides and therefore allow a reduced processing temperature.
The RELIGHT project aimed at developing an energy-efficient heating method avoiding wet chemistry. This new method aims to significantly reduce operation cost for a recycling plant and will not create additional waste streams (in contrast to a wet chemistry method).
The purpose of the proposed bench scale microwave equipment was to raise the temperature of glass waste and phosphor powder, both contaminated with mercury, from ambient temperatures to 200 – 500 ° C and thereby vaporize the mercury which will be driven off and collected outside the microwave cavity using appropriate condensers and filters.
Once designed, built and functionally tested, the microwave unit will be trialled at the premises of one of the project partners, WISER. The objectives of the trials was to:
• Determine the effectiveness of the microwave heating in driving off the mercury;
• Establish the characteristics of the process;
• Provide design data for future industrial scale units
• Identify any issues related to the microwave heating which may influence the design of industrial units.
The proposed bench scale unit will be batch and based on a 6 kW, 2450 MHz microwave power supply: this specification is due to the handling and availability of the raw material and the availability of a microwave power supply. Auxiliary heating for the surface of the drum was provided by infra-red elements mounted on the walls of the cavity.
The process envisaged two possible material streams for mercury decontamination by dielectric heating with electromagnetic energy:
• Crushed glass, requiring a final mercury content of 2 ppm;
• Phosphor powder, requiring a final mercury content of either ≤ 2 ppm or ≤ 50 ppm depending on the intended final use of the “decontaminated” phosphor.
The target parameters for a future industrial unit are shown in figure 3:
It was assumed that the waste in each case is largely free of plastic material. Separation of the various component materials is a task within work package WP2.
This task was carried out across both periods and the summary graphs are shown below
• Microwave decontamination of glass (figure 4)
The mercury content of the samples was obtained using standard techniques employing acid digestion and atomic absorption methods.
It can be seen in the figure above that 1 ppm mercury is achieved at temperatures ~ 250 – 350 ºC, the target level was achieved.
• Microwave decontamination of a phosphor/glass mix (~ 40% glass by weight, figure 5)
It is seen that the remaining mercury content plateau’s at around 15 ppm for temperatures of 250 – 450 ºC. While the upper target, < 50 ppm, was achieved the lower target was not (~1 ppm). In comparison with the contaminated glass, it is to be expected that the mercury on the contaminated phosphor will be more tightly bound and so should require higher temperatures.
In any case, these are encouraging, preliminary results for the glass and the phosphor/glass mix, using a relatively crude set up, these results were transferred from the lab scale to the pilot scale.
Development of System Design
The rationale of this project is that the volumetric heating characteristic of dielectric heating offers a number of significant process advantages. In developing the concept, the key areas for consideration were:
• The ability of the material to absorb electromagnetic energy;
• Can electromagnetic heating be used to remove mercury from the glass and phosphor waste produced in the treatment of fluorescent bulbs;
• Is the heating inherently uniform or non-uniform and if the latter how can any shortcomings this may produce be overcome;
• What is the potential efficiency of the process in terms of transfer of microwave energy to the product and the overall energy requirements of the heating process;
• Looking forward, what implications do the above have for the design of the bench scale unit and future industrial units?
The conclusions drawn from the work are:
• Glass is a poor to medium absorber of electromagnetic energy at radio and microwave frequencies but the absorption is adequate for present purposes;
• Absorption increases with increasing temperature, an undesirable effect when combined with possible non- uniform heating;
• Small scale, preliminary tests have achieved mercury decontamination of glass and a glass /phosphor mix down to levels of 1 ppm for the glass and ~15 ppm for the glass/phosphor mix;
• The benefit of volumetric heating can be exploited but the process will be easier to control and non-uniform heating easier to manage the smaller the power density; preliminary tests suggest < 0.5 kW per kg of glass;
• The dielectric properties of glass are similar at radio frequency and microwave frequencies and consequently microwaves are preferred since the electric fields required will be ten times smaller and arcing will be less likely;
• The benefit of a more uniform electric field distribution at radio frequencies cannot be exploited because non-uniform heating arises principally due to the non-homogeneity of the glass bed;
• Efficient transfer of microwave energy from the microwave generator to the glass, glass/phosphor waste should be possible at an industrial scale;
• Infra red heating does not provide the benefit of volumetric heating and is not as fast as dielectric heating; however it is relatively simple and may worthy of consideration as a means of augmenting the microwave heating if required;
• Estimates of the installed energy requirements and cost of the microwave generators has been made; the higher added value and smaller energy requirement for decontamination of phosphor/glass mixes may offer a low risk entry point for initial exploitation.
• The key challenge was seen to be the uniform heating of the glass bed: the glass bed needs to be well-mixed so that all glass pieces have a similar heating profile and adjacent pieces are in constant relative motion to avoid overheating and fusing of glass at points of contact.
With all these considerations taken on board the following unit was designed and built by the team at CTECH:
An outline drawing is shown in figure 6.
For the decontamination tests the pilot rig drum (figure 7) was used with the following procedure:
• The pilot rig drum was charged with a 5 - 7.5kg sample of Hg contaminated glass;
• The sample was then subjected to microwave heating in the pilot microwave cavity for periods of 50 - 100 minutes;
• After each heating period (100oC incremental rises), approximately 9g of the glass would be collected for analysis and the temperature recorded - measured in the glass bed by door mounted pyrometer:
The above trials were repeated to confirm results – this result is very positive showing the use of MW energy to remove mercury from glass (figure 8). The temperatures reached are much lower than first expected. This points to a level of selective mercury heating in the glass as it is expected that a temperature of approximately 320degC would be required in the glass to remove mercury.
Decontamination trials with WISER CFL phosphor
For the decontamination tests the pilot rig table (see below) was used with the following procedure:
• The pilot rig table was installed and a ceramic sager charged with a 7.5kg sample of Hg contaminated phosphor;
• The sample was then subjected to microwave heating in the pilot microwave cavity for periods of 50 - 100 minutes;
• After each heating period (50oC incremental rises), approximately 9g of the phosphor powder would be collected for analysis and the temperature recorded - measured in the phosphor bed by door mounted pyrometer (during sampling manual temp measurements were taken and it was seen that there was little difference in temperature profile across the large sample):
Results achieved are excellent – temperature required is well below 200oC to remove the majority of mercury (figure 9). The process time of 2 hours is well below that of current industrial distillation (8-24 hours) using standard heating processes. An increase in temperature will certainly reduce the mercury content (seen on smaller scale) below the 18ppm reached. During sampling the temperature profile was monitored (depth and width) and it was seen that a variance of only 5oC was seen in the depth – the hotter temperatures were seen at the base of the sagger. The sample size of 7.5Kg can be increased easily by using multiple saggers.
Conclusions and implications for future processing:
The rationale of this project was that the volumetric heating characteristic of dielectric heating offers a number of significant process advantages. With this volumetric heating advantage it is believed that this process could be expanded further to increase the volume to production volumes.
The conclusions drawn from the work are:
• The dielectric properties of glass are similar at radio frequency and microwave frequencies and consequently microwaves are preferred since the electric fields required will be ten times smaller and arcing will be less likely;
• The glass bed needs to be well-mixed so that all glass pieces have a similar heating profile and adjacent pieces are in constant relative motion to avoid overheating and fusing of glass at points of contact – this can be done in the pilot rig and uniform heating is observed.
• Efficient transfer of microwave energy from the microwave generator to the glass, glass/phosphor waste would be possible at an industrial scale;
• Infra-red heating does not provide the benefit of volumetric heating and is not as fast as dielectric heating; however it is relatively simple and is a valuable addition to the design to ‘kick start’ the heating profile;
• Microwave heating can decontaminate glass to a level below 1ppm – a level which may have to be reached if legislation is changed.
• Mercury is removed from the glass with temperatures as low as 200oC pointing the possibility of selective mercury heating.
• Microwave heating can decontaminate phosphor to a level below 20ppm
• Mercury is removed from the powder with temperatures as low as 160oC pointing the possibility of selective mercury heating.
4. Separation Step 4 : E-base
The objective of the work carried out in this step of the process was to develop a cost-effective process for small-scale recycling operations which provides enhanced separation of CFL e-bases and recover valuable components. Plastics, printed circuit boards and metal parts should be separated to such an extent that obtained fractions are clean and will constitute a value for materials recycling thus making the process profitable.
Material composition
The initial task was to clarify the material composition of CFLs in order to enable the operational processing parameters to be defined since the composition and variability of materials may influence the separation and purification processed being developed. End-of-life CFLs currently present in the waste stream, as well as new CFLs expected to be representative of the Italian, Swedish and UK waste streams in a 3 to 5 years time, were selected for analysis. The CFLs were from different applications (households and industrial lighting), from different manufacturers (Philips, Osram, GTG, etc.) and from the countries where the SMEs participating in the project are based (UK, Italy, Sweden) (Figure 10 and Figure 11). The CFLs were manually dismantled and the material fractions (glass, metal, plastics, printed circuit board, etc) were quantified (Figure 12 and Figure 13).
Inductively coupled plasma (ICP) analysis of the materials was conducted and showed value in metal parts from the electrode bases of CFLs having high concentrations of bronze and aluminium. Electrodes were also shown to contain bronze and electrode wires a mixture of copper, nickel and iron. Fourier transform infrared spectroscopy (FTIR) analysis of plastic parts showed some of them were made of pure polybutylene terephtalate (PBT) and others of polybutylene terephtalate with a Mg silicate filler. In two cases additional amine and carbonyl groups were also detected.
Regarding the higher value metal fraction, it was found that the printed circuit board (PCB) represents a significant weight-% of the e-base in CFLs used in consumer and household (figure 14).
The electrical transformers present on the PCBs (figure 15) have a high copper content, which makes these components particularly interesting for copper recycling with the potential of being an economically viable process due to the high value of copper as a scrap metal. Therefore, copper-containing components on the PCBs were quantified in more details. The components of interest were transformer coils, plastic coated coils, and ring coils (figure 16). The plastic coated coils were primarily of two frequently occurring sizes with a copper content of about 0.4 and 0.9 grams, respectively. An average weight of the copper was calculated to be 0.7 grams per coil. The ring coils showed the lowest mass of copper of about 0.1-0.2 gram per coil.
Separation of e-base components
Crushing and magnetic separation technologies were identified as the most suitable methods to deliver separation of e-base components and to recover the material fractions (polymer, metals, PCBs) contained within the e-bases of CFLs.
A prototype for e-base separation was designed, built and tested. The e-bases are manually loaded in the vibration feeder that feeds the e-bases into the roller crusher unit that crushes the e-bases into a mixed fraction (figure 17) that can be subsequently separated into magnetic and non-magnetic fractions by using an overband magnet (figure 18). The roller crusher consists of two cylindrical rollers mounted in opposite pairs with an adjustable gap. The rollers were custom-designed and built with a pattern that optimizes the breaking of the plastic housing of the e-bases while not crushing the PCBs. The construction of the roller mill enables to modify the roller gap and rotation speed, which enables to optimize the output fractions depending on the e-base fraction being fed into the e-base separator. The plastic housing is sufficiently crushed to have most of the plastic material ending up in the non-magnetic fraction, while only a minor amount of PCB pieces and other metal residues end up in the non-magnetic fraction. The crushed e-bases land on the conveyor belt which transports the material to the overband magnet installed above and across the conveyor belt. Separated ferrous materials are continuously removed by the recirculating belt. The separated magnetic fraction is released out of the first outlet on the side of the separator, while non-magnetic materials remain on the conveyor belt and comes out of the second outlet on the front of the separator. Figure 19 shows a typical input feed (e-bases), roller crushed e-bases at the intermediate stage prior to magnetic separation, and outlet materials (magnetic and non-magnetic fractions).
This approach optimizes the separation of the high-value copper from the low-value plastics of the e-base housings and PCBs. The combined use of a roller crusher and a separation magnet resulted in an increase of the copper content from about 5% in the original e-base fraction up to about 10% in the magnetically separated material fraction.
Scaled-up e-base separation equipment and assessment in an industrial environment
A scaled-up separation equipment for use in demonstration trials was built to process approximately 300 kg/h in line with the processing requirements that were identified as relevant to small-scale recycling companies (figure 20). For the trials in an industrial environment, the e-base separation unit was then transferred to DISMECO and installed at the company’s WEEE pre-processing plant in Bologna (figure 21), where DISMECO can operate the separation equipment within their own processing lines and adapting the processes for the requirements of different inputs.
The separator is designed for easy and continuous operations and all the components are integrated into a single unit with a small footprint of 3.5 m2 for space saving at a recycling plant (figure 22). The assessment trials of the up-scaled e-base separation equipment have shown successful results in separating the e-bases into a metal-rich magnetic fraction and a plastic-rich non-magnetic fraction (Figure 23). During this initial assessment of the equipment, the CFL e-bases were manually fed into the e-base separator through a vibration feeder (Figure 24). In order to maximize the volumes of e-bases being processed and to reduce the need of manual labor and thus operation cost, a conveyor belts has been designed by DISMECO and it is expected to be delivered and installed by the end of December 2014 for full operational assessment of the process line during 2015. The additional conveyor belt will enable the continuous feeding of the e-bases from the Auger screw crusher directly into the e-base separator (Figure 25), which will enable DISMECO to handle large volumes of CFL’s e-bases and recover the components in an efficient and in an industrial scale.
Potential Impact:
• Potential Impact
o Economic Impacts for SMEs
The technology has clear market potential and will have a strong impact on the economic prospects of the participants via two routes:
• The SME participants will use the technology directly in their own manufacturing operations and/or directly in the services they provide.
• MRT will manufacture and market process equipment and complete process lines based on the technology. The overall market introduction will possibly be deliberately delayed on the national markets of the participating recycler SMEs (WISER and DISMECO) to allow them an exclusive use of the high-efficiency processes developed in the project, thus strengthening their competitiveness on their domestic markets. The component/equipment supplier SME (SAIREM) will supply microwave equipment/components (if MW units are required) to the processing lines manufactured by MRT. The IPR agreement between the SMEs will govern any licensing matters related to the sales of equipment developed within the project.
With a target sales price of €300-350k per process line, the initial European market potential would be 15-20 million Euro, which is substantial for the technical coordinating SME, which presently has an annual turnover of €4 million. The initial market potential for sales outside EU is €80-85 million. Taking into account that the technology or parts of it can be applied for recycling LED light sources, the market potential may be considerably higher. Mercury decontamination methodologies may be equally applicable to a range of other market sectors including: mining wastes, contaminated soils, batteries, catalysts. The material separation equipment developed is expected to be applicable across the WEEE waste market sector.
The participants represent different parts of the value chain, as shown in Figure 26.
• The technical coordinating SME (MRT) will manufacture and supply recycling equipment based on the technology developed in the project. As the equipment is expected to meet specifications that no other currently existing equipment can match, MRT will be able to dramatically strengthen its position on the global market. This represents an estimated increase in turnover of 100-300% over five years following market introduction and a need to increase staff by 20-30 persons. MRT normally builds small series of processing lines (custom-made) and larger volumes would enable a more efficient manufacturing process, lowering the manufacturing costs by 20-25%, thus increasing margins. The generated knowledge and established network within the project group will help MRT boosting their future product development and sales, securing a strong market and technology position.
• The supplier of key components (SAIREM) for the recycling process equipment will benefit from the project since it will a) open new application areas for their products, b) increase their sales of components/equipment and c) establish a strong customer-supplier relationship with MRT and the recycler SMEs. If the initial European market potential of a processing line is €15-20 Million, the initial potential for SAIREM would be €1.5-3 Million within 4 years of project completion. The inovative technologies developed may also open up market opportunities across other sectors; for example optimised microwave systems for glass heating in a range of applications.
• The recycler SMEs (WISER and DISMECO) will be test pilots and early adopters of the recycling equipment developed. This will enhance their operations, providing increased volumes and quality of recycled, sellable materials and increased capacity at lower operation cost. This best practice process will enable them to match the WEEE directive requirements (and expected future requirements) for recycling rates. This will increase their competitiveness and help/allow them to obtain larger volumes for treatment. The recycler SMEs estimate that they can increase volumes of waste treated by 400% and increase recycling rates for CFLs to over 90%. More importantly this will move the material to a higher value, lower carbon footprint recycling outlet and increase revenues from sold recycled materials from a current loss of Euro 30 per tonne to an income of Euro 40-100 per tonne. Furthermore operation costs will be reduced by 50%, thus increasing margins significantly. The recyclers would in turn need to increase their number of employees by 50% as the increase in volume requires further resource. The established network within the project group will enable them access to best practice technology and know-how to secure their future competitiveness as WEEE recyclers. Both recycler SMEs anticipate that utilisation of the RELIGHT technology, incorporating both the increased value of recycled materials and enhanced throughput which the technology will enable, will contribute an annual value to their businesses in excess of €100K. After project completion, WISER will continue to host the scaled-up demonstrator system; providing them with instant capability to exploit the new techniques developed.
A techno-economic assessment of the two main methods which were developed for processing and refining the CFLs during the Relight project was carried out. This analysis was done by defining the probable investment and operational costs, which together with expected value of the refined products, allowed for return of investment (ROI) and net present value (NPV) calculations for different scenarios. It should be clarified that the techno-economic assessment does not take into consideration any regulatory demands, but only calculates on the economic benefits of using the new technical equipment that have been developed.
The two main units that have been built are a e-base separator (which separates the e-bases into PCB-rich fraction and plastic-rich fraction), and a microwave (MW) mercury removal demonstrator (which by MW heating evaporates and removes mercury from phosphor powder and the CFL glass).
Calculations were made for MW treatment of phosphor powder which contains high mercury contamination levels of around 1000 ppm (parts per million). The phosphor powder contains oxides of rare earth elements which could be highly valuable. During the CFL recycling however the phosphor powder will inevitably be mixed with crushed glass. Decreasing the mercury contamination will increase the value of the phosphor powder even though it contains glass impurities but far from its pure form. The trials using the MW mercury removal demonstrator shows that while using less energy than conventional methods the ppm level of phosphor powder is decreased within reasonable time down to around 15 ppm. At such ppm levels however the ROI and NPV calculations show little economic incentive at the moment to invest in such equipment. However at higher phosphor powder volumes sold at higher prices there could be economic gains with investing in MW treating equipment that could outweigh the economic risks. More specific, phosphor powder volumes of around and above 150 tonne per year at post treatment prices of around or above 750 €/tonne, which could be achieved if the mercury ppm level is decreased further below 5 ppm, could motivate investment in MW removal equipment.
The glass in CFLs are of different quality and composition, and the decrease of the mercury contamination from around 10 ppm to below 1 ppm does not increase substantially the avenues to sell the glass at higher prices. Therefore little economic incentive was seen in treating the glass fraction to remove the mercury.
Calculations show that the economics of the e-base separator is more viable. Especially for the less labour demanding setup of feeding the e-base separator directly with the e-bases that are separated from the glass and phosphor powder of the CFLs. The calculated ROIs are for such automatic setup between 3.2 and 1.4 years at the expected investment cost, operational cost and profits. The NPV value is also at 10 years end (economic life time) somewhere between €250 000 - €400 000, depending on the discount rate, comparing to €150 000 for if the e-bases are sold unprocessed.
o Effect on Competitiveness on SMEs
Recycling companies WISER and DISMECO will be early adopters of the new technology and will gain a competitive advantage by employing this technology which will provide a step-change improvement in separation and decontamination compared to currently existing technologies. As existing recyclers with established sites and customers they are in an excellent position to be able to exploit the technology. Both companies are technically innovative SMEs who are capable and willing to adopt novel technologies. Adopting the RELIGHT technology will enable them to expand operations and the increasing market volumes of CFL should ensure that this expansion is an excellent fit to broader market needs. WISER currently operates a closed-loop recycling system for fluorescent tubes and would therefore be in a strong position to apply this approach to the CFLs processed by the RELIGHT project. Separated products obtained (e.g. glass) could be sold to their existing customers at an enhanced margin due to the higher levels of purity obtained. As stated previously, the geographic differentiation between these two recycling companies means that they are not directly competitive.
A successful project outcome from the perspective of CFL recycling SMEs WISER and DISMECO will be to:
• Fully separate glass and e-base of the CFL to increase productivity.
• Fully separate constituent materials of the e-base to enable an increased income of approximately €100 to €230 per tonne.
• Increase glass quality and make fit for reuse in a manufacturing process a net increase in income of €20 per tonne
• Reduce costs of mercury removal from phosphor powders by up to euro 800 per tonne.
• Enable phosphors to be in a state suitable for sale to reprocessors to directly recover rare earths – potential value of €2000 per tonne and increasing.
Processes developed within the project should be possible to apply for the efficient recycling of other products containing mercury. New application markets, which require enhanced recovery of mercury from different materials, will be assessed within the project. The technology and knowledge generated in the project will be considered and tested for use recycling of CCFLs, a common light source in liquid crystal display monitors.
One part of the development work, will be to consider the requirements and potential for applying the processes for recycling to the expected future major lighting source, light-emitting diodes (LED). The LED market is expected to grow rapidly, from 5.1 billion USD in 2008 to 16.5 billion USD in 2013, and there will be a strong future need for recycling technology suitable for LEDs.
o Economic Justification of the Research
It is our strong belief and goal that the expected total project cost of €1.24 Million will generate significantly increased revenues to the participating SMEs over a four-year period following the completion of the project. To achieve this, the participating SMEs will have to employ a number of extra persons over the same period of time. Exploitation in other markets and wider geographical uptake mean the long term revenue prospects of all SME partners will be greatly enhanced.
After completion of the project, the goal is to install CFL processing lines at the operation sites of the recycler SMEs for full-scale long-term testing. In parallel, the design of the processing line will be fine-tuned and the manufacturing procedure for the equipment will be further optimized by MRT in collaboration with the component supplier SAIREM. This phase will take 6-12 months before a real market introduction can be made. At market introduction, the installed lines at DISMECO and WISER may serve as reference/demonstration lines both for customers of MRT and customers of the recycler SMEs. The second year after the completion of the project, MRT expects to be able to sell 5-10 CFL processing lines, the third and fourth year 10-20 processing lines per year. The expected impact of a successful project in terms of increased revenues for the SMEs is shown in Figure 27.
At present the partners have no equipment to remove mercury from phosphor and distillation of mercury from the phosphor powder is undertaken by a third party. This is at a cost of nearly £1,000 per tonne. Existing equipment is cost prohibitive with the volumes of lamps that partners currently recycle. A more cost effective means of removing mercury from the phosphor powders will provide an opportunity to market the resultant powders, provide more flexibility in the outlets available, and increase value due to supply and demand. In addition it is not currently feasible for that equipment to remove any residual mercury attached to glass/metal/plastics products. Should there be a need to further process these materials, an alternative continuous flow process that is more cost effective would potentially save many thousands of pounds and process time. The CFL processing site will produce high quality glass cullet resulting in an income of €25 per tonne for the glass rather than the current net cost of -€30 per tonne for aggregate recycling. To clean up the plastics and enable higher quality materials for recycling will increase the value by about €230 per tonne. For an annual tonnage equivalent to WISERs current operations of 100 tonnes per year, this provides a net increase in value of €25,000. The expectation is that CFL tonnages, driven by the rapid increase in usage, will increase 4 fold over the next 3 years. This will therefore provide an annual economic benefit to the SME recycler partners of approximately €100,000. Additional value could be obtained from sale of decontaminated phosphor powder for recovery of rare earth metals. The current throughput of mercury containing lamps is 1,000 tonnes per year with phosphor content (€2,500 per tonne) of 4% the potential annual saving is €41,000. An increased quality of phosphor for sale purpose has the ability to earn revenues of €104,000.
o Contribution Towards Community Societal Objectives
The project aims at developing a process line for handling and recycling discarded CFLs. The global production of CFLs worldwide was close to 3 billion units in 200625. The volume of CFLs appearing in the European waste stream is expected to be 2.5-3 billion units (approximately 500 000 tonnes) over the period 2011-2018.
The process to be developed will;
- Achieve the present and expected future recycling rates of the WEEE directive, enabling an increase in recycling rate from 40-50 weight% (currently) to over 90 weight% in the plants applying the technology. Over the time period 2011-2018 this would represent an increase in European recycled CFL material volumes of more than 200 000 tonnes. This corresponds to a considerable reduction in CO2 emissions due to a more efficient use of resources.
- Handle relatively small waste volumes cost-efficiently, enabling distributed recycling of CFLs and reducing the need and environmental impact of waste transportation.
- Ensure that the recyclers can deliver 50% more cost-efficient services and that the obtained material fractions are of high value and attractive for re-use leading to higher income for the recyclers.
- Exhibit performance and cost characteristics that will be superior to existing technology for small and medium-scale recycling plants. There is presently no technology/equipment which is suitable for small-and-medium-scale recyclers. RELIGHT will develop processes and equipment optimized for handling CFLs, which will deliver purer, re-usable material fractions than current large-scale technology at one third of the investment cost.
As the process equipment should be affordable for distributed recycling, it will also be attractive for customers/users in Asia and Africa, opening a large market and at the same time contributing to increased recycling and more sustainable handling of discarded lighting products in these parts of the world. The annual global market potential for this type of process equipment is estimated at 100 Million Euro (about 300 lines) over the next 5-7 years. It should be pointed out that, MRT has identified a substantial market for their products also among the 4,000 lamp manufacturers in China where there is a need for recycling manufacturing waste.
Legislation & Regulation
The WEEE Directive requires that lamps are collected and recycled and that a recovery rate of 80% is achieved. The Directive is revised regularly, and it is apparent that the required recovery rates will increase with every revision. Currently, a proposed revision is under consideration stating a general increase of 5% in the recovery rates of WEEE. The legislation for handling hazardous substances, such as mercury, and associated emission limits are also expected to become stricter requiring industry to invest in more efficient process equipment. This will also lead to stricter requirements with regards to content of hazardous substances and purity on recycled materials to be approved for re-use.
For companies, be it recyclers or suppliers of recycling equipment, staying ahead of legislation by offering processes and operations that match the future requirements will inevitably provide a strong competitive edge, both on the European market and globally.
Cost Acceptance
As mentioned above, we aim at developing a processing line for small-to-medium-scale recycling being suitable for distributed recycling. It is imperative that such a product is affordable and enables a relatively short pay-back time. The target pricing of the line to be developed must not exceed €350,000 to receive cost acceptance, according to participating recycler SMEs and MRT’s market experience.
o Trans-national Approach
The WEEE directive states that the recycling rate for CFLs should be at least 80%. This is valid for all EU member states. In Europe, waste normally has to be handled in the country where it is generated. Thus, it is of European interest that rational and cost-effective waste handling and recycling technology is made available to operations in all EU member states. In the short term, the current project has the goal to lead to an industrial implementation of a better Best Practise for CFL recycling in UK and Italy. If successful, the technology will be implemented in other European countries and globally. The technology field is relatively narrow and will require the involvement of specialist competence and specialised companies spread over Europe. Moreover, the national markets for recycling equipment are limited in Europe. Thus, transnational collaboration and interaction are important for succeeding with the RELIGHT project. Many of the SMEs in the recycling industry have limited contact with research environments and in many cases the appropriate competence is not found in their own countries. RELIGHT has a large potential to serve as a starting point for increased interactions and development of an established European network for SMEs developing and using sustainable WEEE recycling technology.
MRT will take on a major role for commercialising the technology developed in the project in the form of lamp-recycling equipment to be marketed globally. SAIREM will commercialize microwave heat treatment equipment for recycling applications in collaboration with MRT which has the market insight. WISER and DISMECO will implement the technology in their operations being full-scale test sites for the equipment developed and manufactured by MRT/SAIREM.
MRT has already its major market outside Sweden and has established an efficient sales organisation throughout Europe, which will be used for introducing the process technology developed in RELIGHT on the European market. In order to maintain its competitiveness, MRT has identified the need for methods enabling >90% recycling rates, thus matching the future requirements of the WEEE directive for lighting products. The key for achieving this is to have methods that can separate materials into pure fractions with mercury content below 1 ppm. This would yield recycled materials of higher value and would increase the attractiveness and market price for re-use.
It is clear that the WEEE directive has forced the development of advanced recycling technology in Europe. Similar directives have been and are being implemented in Asia, creating a business opportunity for European suppliers of recycling equipment meeting the requirements of the new directives in Asia. However, pricing and cost-effectiveness is important in Asia, where most recycling plants are still relatively small compared to other industrial manufacturing plants. The RELIGHT project is targeting a method for small-to-medium-scale recycling plants yielding high-value materials and being cost-effective. If the project is successful, it will considerably strengthen the position for MRT in Asia and allow MRT/SAIREM to compete with emerging Asian suppliers of recycling equipment. It will also show the way for other European SMEs and recycling technologies.
o Potential impact from further research
After completion of the project, the onward research and development related to the technology will comprise the following steps:
• Evaluation of the CFL processing line at the operation sites of the recycler SMEs in full-scale long-term testing. The performance of the line will be evaluated in terms of capacity, robustness (availability), purity of obtained materials, mercury emissions, working environment and potential for cost reduction/margin increase. This phase will take 6-9 months.
• Based on the results, the line will be optimized and fine-tuned, during 3-6 months.
• The next generation of processing line will include process steps for recovering rare earth metals from the phosphor powder. Currently, cost-effective technology for recovering valuable materials, such as Europium and Yttrium, from phosphor powders is not readily available. This may be done in a separate project parallel to RELIGHT or as a natural continuation of RELIGHT. This would also include research for developing applications for recycled phosphor powders (free from mercury and rare earth metals). This step should only be incorporated if the value of recovered rare earth metals exceeds the processing cost.
• The importance of separating different types of plastics in the waste stream will increase continuously. In 3-4 years, the demand for recycled plastics (e.g. from WEEE) will be significant leading to augmented material prices. It is then expected to be feasible to incorporate a plastics separation step as a part of the E-base separation process. This may be adjusted to suit discarded lamps and the major plastics used therein.
An exploitation plan has been prepared during the project (initial version completed at month 6 and final version submitted at M24), reviewed regularly at project meetings and finalised prior to project completion to define and protect foreground intellectual property and know-how created. The plan focused on the most promising results matched with the most vibrant market opportunities.
Market acceptance has been established through close consultation with the customer. In WP5, the suitability of recovered components for high-value applications were evaluated with potential end-user companies and organisations to ensure effective product evaluation.
Exploitation and dissemination are extremely important activities within RELIGHT. The consortium partnership is eager to disseminate the results from this project as widely as possible and to maximise the commercial impact of the results and technologies developed during the project through a proactive and strategic exploitation plan.
However, the consortium is also aware that it must maintain confidentiality of its know-how and protect its IPR position in order to establish a strong position in such a competitive market. Therefore, although dissemination was pursued as quickly as possible, it will at all times be subordinate to the IPR protection – this will continue well beyond the end of the project. WP 7 was planned to specifically deal with Dissemination and Exploitation and the related issues of IP protection and Training (technology transfer).
A proactive exploitation strategy has been adopted to ensure that the economic, commercial and developmental impacts of the outputs from RELIGHT are maximised. The potential for exploitation of the technologies developed and the recycled products were continually evaluated as part of WP7. A detailed summary of all the dissemination activities can be found in the final report. Activities included talks at conferences and trade events to publications in national press and scientific journals.
List of Websites:
http://www.relightproject.eu/