Recovery of metal values from industrial wastes

Laboratory scale study was carried out to recover the metal values from ash sample obtained from non-ferrous foundry waste. Sulphation roasting of the sample mixed with selective additive materials converted copper and zinc to water soluble products to the extent of 98 and 88% respectively. Iron solubility was kept to the minimum. The crystallised product, copper sulphate pentahydrate grade, from the leached liquor could be effectively used for non-traditional purpose including in the agricultural field as micro-nutrients. (Shri P.K. Som and Shri S.K. Roy Choudhury, National Metallurgical Laboratory)