METHOD OF RECOVERY OF ZINC OXIDE (VARIANTS) Russian patent published in 1998 - IPC

FIELD: recovery of zinc oxide from industrial waste materials containing various components including zinc, lead, iron and cadmium. SUBSTANCE: waste material is treated with ammonium chloride solution at elevated temperature, insoluble components are separated from solution, solution is treated with metallic zinc to force undesirable metal ions from solution, the solution is then cooled to deposit zinc compounds therefrom, deposited zinc compounds are washed to remove undesirable compounds such as zinc diaminodichloride and remaining zinc compound (which is essentially zinc hydroxide) is dried to obtain essentially pure zinc oxide. EFFECT: more efficient recovery method. 23 cl, 6 dwg, 4 tbl