SILVER RECOVERY FROM LEACH RESIDUES UTILISING LIME AND ALKALI CARBONATE PRIOR TO CONVENTIONAL SILVER RECOVERY TREATMENT

摘要

In the recovery of silver from a residue obtained by acidic pressure oxidation leaching of iron containing sulphidic material, a residue, which is essentially free of elemental sulphur, is treated with lime at a temperature of at least about 80 DEG C to raise the pH of the slurry to at least about 9 for a period of from 0.5 to 4 hours prior to the recovery of the silver therefrom. Preferably the elemental sulphur free residue is produced by oxidizing the sulphidic material under conditions which produce only minimal amounts of elemental sulphur in the residue.