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Abstract

A process for treating zinc sulphide materials wherein the sub-divided material is firstly leached, under pressure at less than 119.degree. C., with a sulphate leach solution low in sulphuric acid and having a high iron content together with zinc and impurities in a manner causing iron to precipitate and subsequently leaching the residue and redissolving the iron precipitate with spent electrolyte containing regenerated sulphuric acid resulting from the treatment of the leach liquor obtained from the first leach step and wherein the leach solution from the subsequent leach step constitutes the starting leach solution for the first leach step. The second leach step is carried out in two phases; a first leach phase conducted at elevated pressure and elevated temperature (less than 119.degree. C.) in the presence of oxygen and a second phase at atmospheric pressure and without the supply of free oxygen to the leach solution.

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