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STOICISM Report Summary

Project ID: 310645
Funded under: FP7-NMP
Country: United Kingdom

Final Report Summary - STOICISM (Sustainable Technologies for Calcined Industrial Minerals in Europe)

Executive Summary:
One of the strongest industrial activities in Europe is the extraction and processing of industrial minerals. More than 150 million tonnes of products are extracted in the EU per year and the mining industry offers direct employment to more than 40,000 people. It is essential to maintain a secure supply of sustainable mineral products to the European mining, mineral and manufacturing industries.

The STOICISM project, funded by the 7th Framework Programme (FP7) managed the research, development and demonstration of a range of new innovative technologies along the industrial minerals value chain. This included developments in extraction, beneficiation, drying, calcining and waste recycling. In the last 18 months of the project, important progress has been made in the research of all stages of the value chain.

For the extraction stage, remote monitoring methods in active china clay pits in the St. Austell region have been tested in order to characterise the geotechnical properties for the pit slopes. For the beneficiation stage, triboelectrification techniques were applied for electrostatic beneficiation of DE and also a quick and effective characterisation procedure on selected waste streams has been developed for the CRMs recovery. The development of innovative techniques like microwave, plasma arc generators and fluid bed configuration for drying and calcining have been further tested in the last 18 months and the first samples produced have been characterised and have been be tested in possible applications. Finally, important progress has been made to improve the following: product quality, energy efficiency, environmental performance and economics on the calcining stage by developing a novel process control and monitoring strategy and by integrating the different databases and data sources

STOICISM is expected to impact significantly on the sustainability of the EU's industrial minerals industry by decreasing the use of natural resources (both mineral deposits and energy resources) leading to the sustainable production of better and purer products with less waste and lower environmental impact.

Project website address:

Project Context and Objectives:
Project context:

Any strategy on the sustainable use of minerals needs to reduce the impact on the environment through better energy efficiency, greater use of renewable energy, smarter use of non-renewable resources and higher levels of re-use and recycling. In 2007 it was noted in the Strategic Research Agenda for the ETP on
Sustainable Mineral Resources that all steps along the value chain of raw materials, extending from exploration and extraction to re-use and recycling, need significant research efforts.
Within this context, STOICISM has been developed as an industry-led project to address these needs through the development, demonstration and adoption of new innovative technologies along the industrial minerals value chain. The overarching aim of STOICISM is to develop more resource-efficient and sustainable processing methods for calcined industrial minerals, which are presently energy intensive to produce, with direct combustion of fossil fuels contributing to up to 85% of their carbon emissions.

Project main objectives:

PO1. To evaluate and improve the efficiency of extraction:
a. In-pit material characterisation with photogrammetry, laser scanning, laser induced breakdown spectroscopy, X-ray fluorescence, and infrared spectroscopy.
b. Investigate selective application of electropulse assisted liberation of clay minerals.
c. Critical evaluation of novel and existing extraction methods for clays and comparison with extraction methods for DE and perlite.
Tasks 1.1 and 1.3 of WP1 are related with this objective.
PO2. To develop new beneficiation techniques to allow use of low quality ore and minimise waste:
a. Advanced electrostatic separation process for removal of contaminants.
b. Development of high intensity flotation devices with the potential to increase product recovery.
c. Process for selective flocculation of DE for removal of impurities.
Tasks 2.1, 2.2 and 2.3 of WP2 are related with this objective
PO3. To identify opportunities for waste minimisation and recycling:
a. Processes to recover useful CRMs from raw materials and waste, such as physical separation, advanced flotation technology and embrittlement by high power electromagnetic pulses.
b. A process prototype of up to 500 kg/day, to demonstrate the potential for the high temperature recycling of waste filter cake into useful products.
c. Process for the economic and energy efficient high temperature transformation of micaceous kaolin waste into lightweight construction products.
Tasks 2.6 of WP2 and Tasks 5.3, 5.4, 5.5, 5.6 and 5.7 of WP5 are related with this objective.
PO4. To develop more thermally efficient drying and calcination processes, able to make use of flexible and renewable energy sources:
a. MW/RF, plasmatorch and joule heating assisted drying and calcination technologies, with the potential to reduce energy consumption by up to 40%.
b. Fluidised bed dryers and calciners capable of using biofuel, to reduce CO2 footprint by up to 35%.
c. Conduct R&D into process opportunities for supercritical water syngas to facilitate point (b).
Tasks 3.1, 3.2, 3.4, 3.5, 3.6, 3.7 and 3.8 of WP3 and Tasks 4.2, 4.3, 4.4, 4.5, 4.6 and 4.7 of WP4 are related with this objective.
PO5. To improve product quality, energy efficiency, environmental performance and economics by developing a novel process control and monitoring strategy:
a. Definition of the specifications and requirements for a real time analyser for product brightness and, if feasible, construction of an offline prototype to demonstrate proof of concept.
b. Develop a monitoring and control concept for calcined minerals processes.
Tasks 6.3, 6.4, 6.5, 6.6, 6.7 and 6.8 of WP6 are related with this objective.
PO6. To undertake full carbon footprint calculations and life cycle assessments (LCAs) for the integrated processes and products in order to quantify associated environmental benefits.
Task 2.5 and 7.7 of WP7 are related with this objective.
To disseminate project findings and to exploit the advances to the benefit of the EU's minerals industries and their suppliers, ensuring that the results have a route to exploitation.
Tasks 8.4 and 8.5 of WP8 are related to this objective, Deliverable Report D8.2 reports this in detail.

Project Results:
The aim of WP1 was to develop a better understanding of resources through in-pit characterisation and how this insight could be used to improve the efficiency of mining and downstream processing. In terms of resource characterisation, comprehensive in-pit monitoring of P1 china clay pit in Cornwall, UK, was carried out with 3-D laser scanning and photogrammetry techniques. It was shown that this type of monitoring, through the use of various software packages can provide insight into geotechnical properties of pit slopes, which can also affect safety.
Characterisation of iron and smectite-bearing china clay mineralogy was carried out using infrared spectroscopy and geochemical methods in order to prove correlations between the methods and investigate the size fractions that these mineralogies are present in. Classification of Diatomaceous Earth (DE) and Perlite ores has been carried out using Laser Induced Breakdown Spectroscopy (LIBS) and Reflectance Spectroscopy. Using historical data, a series of estimates have been produced, using different methodologies, to enhance the known resource in and around Blackpool pit, a currently non-operational pit.
A comparison between novel and existing extraction methods for clays was completed. Comparison, terms of liberation and energy efficiency, with extraction methods for DE and perlite was also completed. Laboratory scale tests of Electropulse assisted liberation of clay minerals have been carried out. It was found it was possible to liberate the clay, but the method displayed poor selectivity between degree of kaolinisation in terms of energy consumption.

The aim of WP2 was to develop beneficiation techniques to allow the use of low grade ores (mainly DE) and recover CRMs from kaolin waste streams.
The main studies in WP2 have been focused in two main areas:
DE cleaning processes: Separation of CaCO3 from DE;
In this WP, the dry (tribo-electrostatic) and wet (selective flocculation and high intensity flotation) methods have been investigated for the separation of CaCO3 from DE. The sample was comprehensively characterised before using the mineral separation techniques.

Electrostatic Beneficiation of DE: In this study, the corona electrostatic separator showed poor separation due to conductivity and particle size. However, the results demonstrated that the mesh-belt triboelectrostatic mineral separator was far superior to the conventional electrostatic separator for the DE cleaning process. In the best batch, separator recovered 54% of DE with purity of 88%. The trial post-studies on the feed and produced samples showed that higher degree of liberation of particles, functionalising the DE surface, scavenging and cleaning can optimise the process.

Selective Flocculation in the Beneficiation of DE: In this investigation, first, the dispersion process for preventing heterocoagulation was intensively studied. The results showed that solid:liquid ratio, temperature, dispersing agent and the interaction between pH and dispersing agent, respectively, were all significant at 30 and 60 minutes of the process. Also, a comparative study between 14 different dispersants on the two different size fractions D50= 10.79µm and 5.49 µm demonstrated that calgon was the most apropriate dispersants between other dispersants examined. Two different flocculants and promoters were investigated in the first set of selective flocculation experiments, in this part of the study the flocculant S8784 showed the most promising result with 61% separation efficiency.
• Intensity Flotation in the Beneficiation of DE: A comprehensive study has been performed on the inverse DE flotation. Various collectors such as: oleic acid, sodium oleate, RBD 15, UL01, UL02, UL04 and A6493, and dispersants such as: Na2SiO3 and the influence of ultrasound were examined.

The highest separation efficiency of 70.4% was obtained with using UL01=1.5kg/t as collector and Na2SiO3 = 0.5kg/t as dispersant.

The viability of W, Nb, Ta, LREE and Sn recoveries from kaolin current waste streams. In this study, micaceous residue and LREE& Sn were recognised as the most valuable waste stream and metals content. The CRM-bearing minerals such as wolframite, cassiterite and monazite were identified and characterised. The pilot scale sample from micaceous residue of biotite granite was prepared for the metallurgical test-work. Different pre-concentration and concentration methods such as: spiral, shaking table, falcon, flotation and magnetic separation have been evaluated on the samples.

Supecritical Water Syngas generation: For this task syngas generation in supercritical water has been simulated using glycerol as a model input substance. It was observed that temperature is the most important parameter. Below 500°C, methane and carbon dioxide are the most common. Hydrogen and carbon dioxide have the higher ratios above 500°C. The maximum proportion of hydrogen is at 900°C when its ratio slightly is reduced due to water-gas shift reaction. The methanisation reactions are most common in the temperatures near critical point. Low concentrations of glycerol are in favour of higher amounts of hydrogen and carbon dioxide / higher concentrations are preferred for higher amounts of methane.
Development of filtration process: IMERYS has performed laboratory tests to determine the effectiveness of vacuum filtration on DE slurry. Low moisture content of 57 wt.% at 90 minutes residence time was achieved using lab Buchner filter which is acceptable. Lower humidity levels (approximately 54%) could be achieved over longer filtration periods and so industrial vacuum filtration seems quite promising. Work has also been carried out on the Rf filtration and dewatering of DE. It was observed that with 21% solids DE feed pressing, the maximum solids achieved was 46% solids without RF heating and 48 % solids after 20 minutes of RF heating with no change after 1 hr. Moreover higher RF power and longer residence time showed no significant benefit.
MW/RF assisted drying of DE and kaolin: Work has been carried out on small scale samples. The batch heating of samples does not translate to a realistic process and heat losses are too excessive to measure power inputs. This work was therefore delayed in RP2 and was later completed in WP3 in parallel with operation of the rotary calcination work in WP4. The rotary kiln was used to test dry materials with and without MW and the energy consumption was compared.
Plasmatorch or Joule heating drying of DE and kaolin: The efficiency of heat transfer has been simulated and evaluated at a gas flow rate of 90 l/min. It was observed that the material in the axis has significantly higher temperatures than the material which is more than 3-4 cm besides the axis.
For flow 90 l/min, the efficiency achieved was 7.93% for stationary simulation and 9.47% for transient simulation. To further increase the efficiency, the flow rate was reduced to get higher thermal energy transfer from the gas into processed material, thus achieving 12.5% efficiency. Since the results achieved aren't promising enough for industrial processing, the focus for RP3 was now on the Joule heat assisted drying of minerals.
Fluid bed drying of DE: TEMA have designed and manufactured a small shaking cylinder to facilitate a small batch dryer to determine if fluid bed technology is suitable for drying DE. A batch drying test was performed on the shaking cylinder with prepared DE material with a moisture content of 42% and a steady drying temperature of 200°C. The process parameters determined were used to prepare and set-up the pilot scale fluid bed dryer for drying tests. Equipment was selected and the burner could be changed for using biofuel. The challenge was then to identify a suitable biogas supplier.

For the fluidized bed calcination, the fluidization tests on small scale were completed, results yielding preferred operation conditions for the pilot scale tests (200 mm diameter plant). The pilot scale plant was modified for operation with 'biogas', (a synthetic mix of individual components) and commissioned. The first test with kaolin was performed and results for the analysis are to be presented soon. Remaining materials were tested in the next period RP3 and further tests were needed in order to optimize the overall processes.
For the microwave assisted rotary calcination the main effort has been completing the design with increased heating capacity and according increase of tube length and support. The commissioning was completed successfully, however, for a better material handling, minor modifications were needed. The microwave (MW) assisted rotary kiln is a direct/indirect hybrid heating design which can be tilted up to 5°, the operating temperature is 1050°C max, due to material limitation.
For the plasmatorch and joule heating assisted calcination different anode/cathode materials were tested as well as their lifetime. Further, calculations were performed for the heating of layers and particles of some tens of microns, showing that the calcination rate is highly dependent on the area per volume ratio of the heated particle. It was further investigated in RP3 to see if the heat transport through the material is not fast enough and the calcination is hindered by surface sintering.
In the supercritical water syngas process glycerol was tested as a model hydrocarbon for a range of temperatures and residence times suitable for gasification. The measured results were compared to the thermodynamic model for validation. With this model substance, the gasification was incomplete and carbon formation occurred in some experiments.
The validation of the products was a continuous task which was carried out for all produced materials, determining operating conditions for further experiments. The LCA was completed for the calcination processes.

The aim of WP5 was to identify opportunities for waste minimisation and recycling in the minerals industry.
The main activities in P5 have been in two main areas:
1. Prototype equipment for recycling and
2. The development of new light-weight materials from kaolinitic waste

The main achievement in Activity 1 for the period RP2 was been the completion and commissioning of the Torbed™ calciner for the waste filtration materials. In addition, laboratory work was carried out on the waste materials from partners 14 and 16, Bio Aceites del Sur (BDS) and Fuller's brewery, and it was characterised and recycled in the laboratory by P1 and P6. Work for RP3 was then carried out on the waste materials using the newly commissioned Torbed calciner.
The main achievement in Activity 2 for RP2 was the development of new light-weight materials. The new materials did not use resources from natural mineral deposits but are formed from kaolin waste, glass waste and sewage sludge. The new materials have a density lower than unity and possess the appropriate and competitive properties for their end-uses in construction materials, thermal and sound insulation, horticulture and other useful applications. The materials met the entire initial critical objectives of the project for RP2. P4 had also developed an outline laboratory process to produce the materials.

The aim of the WP6 is to develop the integrated monitoring and control concept for the calcination processing chain. The main objective is to control the multiple hearth furnace based on its feedtype and to minimize its energy consumption.
The first task has been Integration of the different data sources, reporting and monitoring, aiming at developing software platform to integrate the different data source files (mine data, plant operation data, QC data, lab data) to one centralised plant database as well as interface to distribute the data for further analysis, reporting and monitoring. The task has been ended and the software successfully tested with the industrial data by Predict.
The second main task has been the feedtype identification for feedforward control and monitoring purposes of the calciner.
The main progress in the analyser development has been the characterization of the calciner feed and products, in order to set the parameters that the analyser should further assess. By using Infrared Reflectance Spectroscopy it has been possible to identify the iron phases in the calciner feed, as well as the metakaolinite - mullite transition phase. Reflectance Spectroscopy in the visible range has been used as an alternative method to characterize the quality properties of the calciner products. All the parameters measured by the on-line analyser were added to the integrated concept of monitoring and control by Delft University partner in RP3.
The third task in the concept development is the design of the control and monitoring methods for the calciner.
Different strategies for optimization of the furnace operation have been proposed by Aalto University. All strategies are feedforward and based on the product type and the degree of necessary kaolin treatment which are selected according to the mineralogical properties of the feedtype. A data-based model is developed predicting the gas temperature profile in the MHF according to the process inputs (the feedrate, the combustion gas flows to the Hearths 4 and 6) and the temperature of the furnace walls.
The optimization strategy itself considered the contents of mullite, which is an undesirable side Product. The target level of mullite can be specified for each product grade that is selected according to the mineralogy properties of the kaolin. The mullite content in the product is not measured online. Instead, a process monitoring strategy is proposed estimating the mullite formation based on the energy balance of the furnace and the softsensors. Optimization and control methods can be MPC (model predictive control) or model-based to manipulate the combustion gas flow rates to the hearths 4 and 6.
All tasks towards the integrated control and monitoring concept have reported very successful and promising results. The partners have worked enthusiastically towards the ambitious goal with the help of the end user Imerys constant help and expertise. The monthly webmeetings and workshops have been organized by the partners and stimulated the work progress.

The partners have published their first scientific articles. The feedback from the Publications has been
very rewarding.
The main activity of this Work Package was the demonstration of the successful and economically viable
technologies. In each case, a proportion of the materials produced were on-processed by P1 to provide final product material suitable for applications testing, end user validation and provision of customer samples. Throughputs and energy data were used for LCA development and integrated flowsheeting. The environmental impacts of the different technologies studied were assessed, taken individually and as a component of an integrated supply chain of mineral products. The introduction of the different technologies developed during the project is likely to trigger several types of process improvements; increasing the efficiency of energy consumption, an increase in the use of renewable energy, reduction of waste generation, recycling of valuable elements and increase in the lifetime of the quarry/mine. The LCA approach was used to consolidate all these individual innovations to measure their impacts on key environmental themes (climate change, depletion of non-renewable materials, water consumption, acidification, air emissions of particulate matters, water rejects, waste production, etc.).

Deliverable Report D7.2 reported on the following Stand-alone Demo activities:
▪ Electropulse assisted disintegration
▪ Selective flocculation
▪ Electrostatic separation
▪ High intensity flotation
▪ Joule heating/plasmatorch assisted calcining
▪ Fluid bed dryer
▪ Fluid bed calciner
▪ Algorithms for calciner control
▪ Online analysis equipment (brightness)
▪ MW-rotary kiln
▪ Torbed calciner for recycle of waste filtration cake
▪ Micaceous kaolin waste recycling process

And also on the following:
Sample evaluation
▪ Decorative paint formulation
▪ Filtration products validation
For this Reporting Period RP3, the main important activities to highlight are:
1. The presentation of the findings of STOICISM in even more events/conferences/seminars compared to both the first and second reporting periods. The events can be summarised as International, European and Local Industry dedicated events and the total reach out is estimated to be around from 1000 to 2000 people in the events.
2. Through the network of IMA Europe, the entire industrial minerals sector represented by IMA is estimated to be around 46,000 people.
3. As defined in the exploitation strategy and to reach out at the various stakeholders and meet their expectations, various additional publicity materials were prepared.
4. Planning and delivery of the STOICISM Closing Event in Brussels in November 2016.
5. Create further awareness for the project and liaise with even more industry partners than previously to implement the exploitation strategy.
6. Two awards from the PhD & Master researchers which are partners in the consortium.
7. To close the language barrier: Translate some of the website pages and present to national audiences (in French).
8. Complete and submit Deliverable Report D8.2 ‘Publication materials’

Potential Impact:
STOICISM is expected to impact significantly on the sustainability of the EU's industrial minerals industry by decreasing the use of natural resources (both mineral deposits and energy resources) leading to the sustainable production of better and purer products with less waste and lower environmental impact.

List of Websites:

Frédéric Jouffret
Director of Technology
Imerys Talc Europe / F&PA EMEA
Tel: +33 561 50 20 15
Fax: +33 5 61 40 06 23

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