Menetelmä sinkkiä ja rautaa siältävien sulfidien käsittelemiseksi

Sulphur and a solution containing a predetermined concentration of zinc sulphate (preferably 150 g. Zn/1), are prepared from zinc sulphide ores containing iron by leaching the ore with sufficient sulphuric acid to form the required concentration of zinc sulphate, but insufficient to react with all the sulphide (100 moles acid to 120-160 moles of sulphide), and heating this slurry to a temperature above the melting-point of sulphur, preferably 125-160 DEG C. with a free oxygen-containing gas at an oxygen overpressure of at least 5 p.s.i., preferably 20-100 p.s.i. This oxidizes the sulphide to sulphur, forms ZnSO4 solution and oxidizes and hydrolyses the iron to an insoluble basic sulphate which precipitates, the reaction generally being continued until the iron concentration in solution is less than 1 gram per litre. The leach solution is then separated from the residue and may be treated, e.g. by electrolysis, to extract zinc. The unreacted sulphide and sulphur are separated from the residue and the sulphur is then extracted from the sulphide by volatilization, solvent extraction or other methods. The sulphide left is then recycled to the first step.