Abstract: A process for recovering zinc from material containing zinc ferrite includes leaching the ferrite containing material together with zinc sulphide containing material in a leach step, with the relative amounts of ferrite material and zinc sulphide material being such that the zinc present as zinc ferrite is a minor proportion of the total zinc content of the ferrite material and the zinc sulphide material. The leach step is carried out in aqueous sulphuric acid solution at elevated pressure under oxidizing conditions and at a temperature above the melting point of sulphur, with the sulphuric acid to zinc molar ratio being less than about 1.2:1, to cause dissolution of a substantial amount of zinc from the ferrite material and from the sulphide material.

Abstract: A process for recovering zinc from zinc-containing sulphidic material which also contains iron and lead includes leaching the material under oxidizing conditions at a temperature in the range of from about 130.degree. to about 155.degree. C. in aqueous sulphuric acid solution with a stoichiometric excess of sulphuric acid relative to the zinc content of the material of from about 50 to about 100% to produce an undissolved residue containing a major proportion of the lead and a leach solution containing a major proportion of the zinc and iron. The sulphur and lead containing residue is separated from the zinc and iron containing leach solution. Elemental sulphur is physically separated from the remaining lead-containing residue, and the remaining lead-containing residue is recovered. The zinc and iron containing leach solution is treated to recover zinc by feeding the solution to another process in which zinc-containing material is treated to recover zinc and which includes an iron-precipitation step.

Abstract: A process for removing manganese and chloride ions from an aqueous acidic sulphate solution containing zinc, manganese and chloride ions without removing a substantial amount of zinc ions from the solution includes adjusting the free acidity of the solution if necessary to at least about 0.1 molar. The solution is then treated with ozone to oxidize manganese ions to manganese dioxide, and the ozone treatment is continued after the manganese concentration has fallen to a low level to oxidize chloride ions to chlorine gas. The precipitated manganese dioxide is removed from the solution.

Abstract: A process for removing manganese ions from aqueous acidic sulphate solutions containing zinc and manganese ions, without removing a substantial amount of zinc ions from solution, includes treating the solution with ozone to oxidize manganese ions to manganese dioxide, and removing the manganese dioxide from the solution.

Abstract: A process for recovering zinc and manganese dioxide from material containing zinc and manganese compounds, includes leaching the material to provide an aqueous solution containing manganese and zinc ions, electrolyzing the solution in one electrolytic cell with conditions inhibiting the formation of manganese dioxide and favoring the deposition of zinc, and electrolyzing the solution in another electrolytic cell with conditions favoring the formation of manganese dioxide. Zinc is removed from the one electrolytic cell and manganese dioxide is removed from the other electrolytic cell.