Abstract: A process for reducing arsenic content from arsenic-bearing gold concentrate or other arsenic-bearing gold materials to produce a low arsenic-bearing gold concentrate. The process may comprise adding oxygen, water, and/or acid to an acidulated arsenic-bearing gold concentrate slurry and reacting them together in an autoclave at an elevated pressure and temperature in a pressure oxidation step. In one or more examples, the process may further comprise processing the oxidized concentrate slurry in an arsenic re-dissolution step to dissolve unstable solid arsenic compounds, and applying a first solid/liquid separation and wash step to form a first washed slurry/solid and first acid-containing solutions. The process may further comprise reacting the first washed slurry/solid with sulfur dioxide in a reductive leach step, and applying a second solid/liquid separation and wash step to form a second washed slurry/solid and second acid-containing solutions.

Abstract: A process for recovering silver from silver-bearing gold concentrate or other silver-bearing material which may comprise adding oxygen, water, and/or acid to an acidulated concentrate slurry of an input silver bearing material and reacting them together in an autoclave at an elevated pressure and temperature in a pressure oxidation step; processing the oxidized concentrate slurry in a post pressure oxidation conditioning step; applying a first solid/liquid separation and wash step and a filter and wash step to form a first washed slurry/solid and first acid-containing solutions; reacting the first washed slurry/solid with sulfur dioxide in a reductive leach step; applying a second solid/liquid separation and wash step to form a second washed slurry/solid and second acid-containing solutions; and applying an optional surface cleaning step, to produce a free-milling silver-bearing material, which is amenable to conventional cyanidation to recover the silver therefrom.

Abstract: 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.