Effect of Exposure Time, Lining Material and Plasma Gas on the Extraction of Aluminium from Waste by Smelting Reduction

Abstract

Today’s world has experienced the change in the extraction of metal from its native ore to that from secondary resources. The ash and tailings are such secondary resources for extraction of aluminium. The present investigation shows the effect of furnace lining materials and plasma gas on the extraction of aluminium from the waste material during smelting reduction studies. A laboratory scale plasma arc furnace was used for the reduction studies of bottom ash, iron ore slime with charcoal. Experiments in hydrogen and nitrogen plasma environments were carried out inside magnesite and graphite crucible separately. The rate of reduced metal absorption by the liquid metal bath for a fixed time was determined. The output of aluminium through metal, slag and exit gas was calculated to establish a tentative mechanism of smelting reduction. Combination of nitrogen plasma and graphite crucible showed the optimum recovery level of reduced aluminium in metal. The high-temperature plasma could reduce highly stable oxides of waste materials, and the recovery of volatile aluminium in metal could be possible by using a metal solvent bath.