Prospects for solvent extraction processes in the Indian context for the recovery of base metals. A review

Details of the research and development work carried out in India using SX for the treatment of the leach/waste solutions and effluents containing base metals are reviewed, focusing on solutions obtained from low-grade or complex ores, secondary resources or industrial wastes. Commercially available organic extractants, such as hydroxyl-oximes, hydroxyl-quinoline, tertiary amines, substituted phosphoric acid and other phosphate based extractants, have been used for the recovery of metals from acidic, alkaline and mixed sulfate–chloride solutions containing copper, nickel, cobalt, zinc and associated metals. The applicability of commercially available tailor-made extractants is described for the purification and enrichment of the metal contents of lean and complex solutions in an Indian context. Research efforts for the separation and recovery of valuable metals by SX are also highlighted. Treatment of solutions for producing metals by crystallization or electrowinning is described.