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Development of new technology for aluminium dross complete recovery

Final Report Summary - ALUCYC (Development of new technology for aluminium dross complete recovery)

Executive Summary:
The Alucyc project has develop a new process to recover metallic aluminium from aluminium dross. Comparing with available state-of-the art technologies, the yield of metallic aluminium will be increased from 95% to 99% using the new technology developed in Alucuc. Alucyc technology is waste-free, cryolite and the remaining aluminium oxcide could be used in melting of primary aluminium as additives. To develop the Alucyc technology, a phase model, novel electro slag furnace with non-consumable electrodes and process and power control systems was designed and integrated. By consultations of primary aluminium smelters, Alucyc technology has raised interest in potential end users in the industry and will be therefore easily exploitable.

Project Context and Objectives:
An environmental problem in need of a solution
The global primary aluminium production volume in 2009 was 36 million metric tons, and regardless of the recession these volumes continue to grow 5-6% per a year. The production of one metric ton of aluminium from ore (bauxite) requires about 17000 kWh of electricity while the same amount of recycled aluminium consumes approximately 750 kWh. Therefore, the recovery of aluminium from, aluminium dross requires only 5% of energy related to that which is needed to produce the aluminium from ore. During aluminium melting the dross is generated, resulting typically 25 kg of dross per metric ton of molten aluminium (3 wt%)2,3. That means 0.9 Million tons of dross per year is generated. The generated dross contains 30-70% (in average 50%) metallic aluminium which equals 0.45 million tons. Today the best technologies in dross processing make possible to get a recovery up-to 94%.
The existing dross processing technology suggests using salts (NaCl, KCl) in amount of 600kg per 1 MT of dross that have serious environmental threat. For economical reasons, it is desirable to recover in usable form as much as possible of the free metal that is carried from the furnace into the dross. However, separation of metal is difficult, because the metal is dispersed as fine particles that are surrounded by a matrix of non-metallic components of the dross. Further, the free metallic aluminium in the more ornless porous dross is highly susceptible to oxidation, especially at elevated temperatures.

Opportunity for European SMEs
· The aluminium production industry is primarily composed of large enterprises
· SMEs are participating in aluminium production supply chain as specific component technologies providers
· To be successful and ensure a position in aluminium manufacturing supply chain, SMEs need to supply unique features and added value technology that have high costefficiency for whole aluminium manufacturing sector.

Economic justification of need
The global aluminium industry is seeking technology that will allow it to save any percent of energy for aluminium production and increase the outcome from primary aluminium dross (PAD) melting process because:
· The most efficient existing process, melting by Tilting Rotary Furnace (TRF), requires € 24 costs for salt additives and € 37 for utilisation of salt slag for processingof 1 metric ton of primary aluminium dross. Recovery of one metric ton of PAD costs vary from € 285 in a smelter with a processing capacity of 1 million tons to € 392 in a smelter with an annual processing capacity of 0.3 million tons.
· Available salt-free recovery processes have poor efficiencies or are hugely expensive.
· New technology will attract end users if the ROI will be less than 5 years;

Enhancing of recovery to 99% instead of 94% (SoA) enables annually:
· Additional yield 22.5 thousand tons of metallic aluminium that enables additional production for € 32 million in total;
· Saving from electric energy consumption of 666 Gwh which generates savings of € 14,5 million.

Techno-economic barriers and user issues
Aluminium dross is classified into three different categories based on the metallic aluminium content i.e. White (primary), Black (secondary) and Salt cake. The main constituent of dross is metallic aluminium that varies 8 – 90 wt% depending upon grades. There have been several methods of processing the dross material in many European countries and Australia, but current metallurgical processes do not allow complete recovery of aluminium from dross. In such cases, some part of the dross is declared as process waste with significant commercial value. Continuing disposing dross to the environment as waste has enormous impact on the environment.

Our goal was to develop a full recovery technology for aluminium dross that enables processing of aluminium dross without salt addition that creates a metallic aluminium yield at least 99% instead of 95%.


Project Results:
The RTD partners did generate the following key results during the project:
1. Process model
2. Power control unit of hydraulic system
3. Control unit software
4. Integrated Alucyc solution.

Potential Impact:
The biggest impact has been identified in the environment benefits of the Alucyc process, which therefor can be determined, as well, as the most important socio-economic impact :

Reduction of energy consumption:
Each Alucyc unit installed (with dross processing capability of 300 KT/year) saves 4.875 (TWh) of electricity each year. Furthermore, based on the market figures for the 10 years post-project, we estimate a total cumulative energy saving of 131 625 TWh. This is the equivalent of a continual 3 GW generator, the same as a medium power station.

Reduced Co2 footprint
Comparing with production of aluminium from primary source 7 tons of CO2 emission and 16 250 kWh/t of electric energy will be saved per 1 ton aluminium produced from aluminium dross.

Reduced primary resource usage:
Additional yield 22.5 thousand tons of metallic aluminium enables the EU to reduce imports or allows for additional production

List of Websites:

The Alucyc project website is reachable by the two different website addresses:
www.alucyc.com
and
www.alucyc.eu .

Future Exploitation and commercialisation:
Metallurg Engineering (http://metallurg.eu/ , mail: metallurg@metallurg.eu )