FREMGANGSMAATE FOR UTVINNING AV SINK FRA SINKHOLDIGE SULFIDISKE MATERIALER.

摘要

A process for the recovery of zinc from zinc-containing sulphidic material which also contains iron and from zinc oxide containing material, at least one of the materials containing lead and/or silver values. The process includes leaching zinc-containing sulphidic material and zinc oxide containing material under pressurized oxidizing conditions at a temperature in the range of from about 130 DEG to about 170 DEG C. in aqueous sulphuric acid solution with a stoichiometric excess of sulphuric acid relative to the zinc content of the materials of from about 40 to about 100% to produce a residue containing a major proportion of lead and/or silver values and a leach solution containing a major proportion of the zinc and iron. The residue is separated from the leach solution and treated to recover lead and/or silver values. The pH of the solution is then raised to neutralize the acid in an iron removal step to cause precipitation of at least some of the dissolved iron from the leach solution as an iron compound. The precipitated iron compound is separated from the remaining leach solution, and the remaining leach solution is treated to recover zinc.