A Pretreatment of Pyritic Gold Concentrate with Catalytic Oxidation Acid Leach

Hanlin, Yang ; Fuerstenau, M. C. ; Guangxiang, Xia ; Wan, R. Y.
Organization: Society for Mining, Metallurgy & Exploration
Pages: 12
Publication Date: Jan 1, 1993
The mechanism and kinetics of pretreatment on pyritic gold concentrate with the catalytic oxidation acid leach (COAL) process were studied in the temperature range of 80-100°C and oxygen pressure range of 230-1013 kPa, with sodium lignosulfonate (SL) and mixed medium of sulfuric acid (11 g/[ ]) and nitric acid (5.5 g/ [ ]). The results show that nitric acid acts as a catalyst, the surfactant changes the hydro-phobicity of resulting elemental sulfur to favor the oxidation of pyrite, and the oxidation-determining step would be the chemical reaction between nitric acid and pyrite. When about 80% of pyrite contained in the concentrate is oxidized, the gold cyanidation extraction exceeds 95 % . The nitric acid in solution can be recycled and used again.
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