New method for aluminum electrolysis in the KF-NaF-AlF3 melt with the Al2O3 addition at cryolite ratio (KF+NaF)/AlF3 in the range of 1.1-1.9 have been developed. The anodic current density is not higher than 1.0 A/cm2 and cathode current density is not higher than 0.9 A/cm2 at temperatures 700-900° C during electrolysis. Carbon-containing materials or inert anodes made of metals, metal alloys (for example, Cu-Fe-Ni alloy), metal oxides and cermets are used as anodes. Proposed technology will provide materials consumption decreasing and process sustainability improving of the electrolytic aluminum production process due to anode and construction materials resource increasing and pollutant emission decreasing. This method with utilizing oxide metallic anodes supposes elimination of resource-demanding carbone anodes production and leads to significant decreasing emission of hazardous polycyclic aromatic hydrocarbon and Green House gases into atmosphere.
Reducing hazardous emission from 65 to 2.6 ths.tonnes at 1 mln.overall aluminum production is expected.
Advantages:
- Capacity increasing and energy consumption decreasing;
- Process producibility improving (including operating costs decrease);
- Construction and electrode materials resource increasing (including oxide-metallic anodes).
