Förfarande för utvinning av zink ur zinksulfidmalmkoncentrat.

摘要

In a process for recovering zinc from zinc-containing sulphidic material which comprises leaching the sulphidic material under pressurized oxidizing conditions at a temperature in the range of from 130 to 170 DEG C with aqueous sulphuric acid solution containing an initial stoichiometric excess of sulphuric acid relative to the zinc content of the sulphidic material, separating the leach liquor from the residue, and treating the leach liquor to recover the dissolved zinc, any iron in the leach liquor is precipitated before separation of the liquor from the residue, by injecting a zinc oxide containing material into the leach slurry, while maintaining the pressurized oxidizing conditions and temperature, the amount of zinc oxide being sufficient to raise the pH of the slurry to a value in the range of from 4.5 to 5.5 thereby to precipitate dissolved iron into the residue and form a leach solution that is substantially iron free.