Review of hydrometallurgical recovery of zinc from industrial wastes

Zinc containing wastes/secondaries viz. zinc ash, dress, flue dusts, sludge , residue etc, are generated in various chemical and metallurgical industri es. The materials contain different level of impurities depending on the so urce. The hydrometallurgical processing is effective and flexible for treat ing such materials as it can control the different level of impurities. Dep ending on the nature and composition of the secondaries, a suitable lixivia nt could be selected to dissolve the desired metals leaving gangue in the r esidue. In the present paper, the hydrometallurgical processes have been de scribed for the recovery of zinc from the secondaries using sulphuric acid, hydrochloric acid, ammoniacal solution and sodium hydroxide etc. as lixivi ants. The leach solution thus obtained has been purified with respect to di ssolved impurities using precipitation, ion exchange or solvent extraction method. The metal or salt is produced from the purified solution by electro lysis or crystallization. (C) 2001 Elsevier Science B.V. All rights reserve d.