Simultaneous Extraction of Zinc and Manganese Dioxide from Zinc Sulphide Concentrate and Manganese Ore

Direct leaching studies of mixture of zinc sulphide concentrate (concentrate) of Himalayan origin and manganese ore (ore) in stoichiometric proportion according to the reaction :
ZnS + Mn02 + 2H2SO4 = ZnSO4 + MnSO4 + S° + 2H20
in dilute sulphuric acid (present in spent liquor from electro-winning cells) were carried out to test its amenability to a novel process developed at National Metallurgical Laboratory (NML). The liberated sulphur in the sludge was extracted in pure form. The effects of controlling parameters viz. acid-concentration, temper-ature and duration of leaching were investigated to opti-mize the leaching conditions. Extraction efficiencies of zinc and sulphur under best condition were —82% each, while that of manganese was —95%. The inextricable portion of zinc sulphide was investigated with the help of XRD analysis of the concentrate and the final residue. The leach solution purified by conventional hydro-metallur-gical technique was fed to an electrolytic cell for
simultaneous electro-winning of zinc and electrolytic manganese dioxide (EMD). The EMD was y-variety as shown by TG/DTA and XRD analyses.