METHOD FOR REDUCING ARSENIC CONTENT IN ARSENIC-BEARING GOLD MATERIAL

摘要

A process for reducing arsenic content from arsenic-bearing gold concentrate or other arsenic-bearing gold materials to produce the low arsenic-bearing gold concentrate. The process comprises: (i) optionally regrinding the input arsenic-bearing gold concentrate; (ii) optionally treating the reground gold concentrate with sulfuric or other aqueous acid in an acidulation step; (iii) adding oxygen, water and/or acid to the acidulated concentrate slurry and reacting them together in an autoclave at an elevated pressure and temperature in a pressure oxidation step; (iv) processing the oxidized concentrate slurry in an arsenic re-dissolution step to dissolve unstable solid arsenic compounds; (v) applying a first solid/liquid separation and wash step, comprising at least one of a thickening step, a counter current decantation (CCD) wash step, and a filter and wash step, to form a first washed slurry/solid and first acid-containing solutions; (vi) reacting the first washed slurry/solid with sulfur dioxide (and optionally sulfuric acid and/or water) in a reductive leach step; (vii) applying a second solid/liquid separation and wash step, comprising at least one of a thickening step, a CCD wash step and a filter and wash step, to form a second washed slurry/solid and second acid-containing solutions, wherein the first and second acid-containing solutions can be recycled to the acidulation and/or pressure oxidation steps; and (viii) applying an optional surface cleaning step, to produce low arsenic bearing gold concentrate.