EFFECTS OF ADDITIVES ON THE ELECTROLYTIC CONSUMPTION OF CARBON ANODESIN ALUMINUM ELECTROLYSIS

The effect of impurities on the anode carbon consumption in aluminium electrolysis was studied in a closed laboratory cell, which allowed th e determination of the total carbon consumption (CC), the carbon gasif ication (CG) and the formation of carbon dust (CD). Addition of V2O3 m ade CC, CG and CD all increase while LiCl addition caused CC and CG to increase, and CD to remain constant. Addition of 0.5 wt% AlF3 lowered CC, but higher contents had a negative effect. Increasing sulphur con tent in the petroleum coke caused a marked decrease in CG, which was p artly counteracted by rising CD. Literature data on the effect of addi tives are discussed together with the results.