Hydrometallurgical processing of zinc-bearing residues and manganiferous materials whichare being generated at a modern zinc electrowinningplant is described. The process involves theutilization of liquid effluent generated at the SO2scrubbing plant where sodium carbonate is used as aneutralizing agent to absorb SO2 in tail gas. Thiseffluent has been found effective in extracting themetal values from the zinc plant process residues. Inthe absence of the liquid effluent, a suitablechemical has been tried and similar results have beenachieved. The results obtained by both types ofmaterials are presented along with the processdescription, operating conditions, specificadvantages and extraction efficiencies. Based on theresults, a simplified flow sheet has been developedand proposed to be incorporated in existing zincsmelting plants. The strength of this paper lies inthe hydrometallurgical processing of manganiferousmaterials such as anode mud and pyrolusite with a viewto obtaining chemically activated manganese dioxide(CMD) and electrolytic manganese dioxide (EMD) fromthe resultant manganous sulphate solution. Theprocess can also be used to enrich cobalt in the cobaltcake with simultaneous removal of impurities presentto benefit the downstream operation of a solventextraction plant, and still further to extract themetal values of roasted zinc calcine and leach residueby modifying this same process approach. The processis very simple, effective and viable, and it can beconsidered as a important technology for convertingwastes in a cost-effective way.
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