A novel process was developed to markedly increase gold cyanidation performance from an arseniccontaining gold-bearing concentrate. Before cyanidation, a two-step bio-oxidation pretreatment wasemployed to decrease the arsenic content in the residue and obtain a high cyanidation efficiency forgold. Bio-oxidation results indicated that most of the arsenic was rapidly removed from the mineralinto the solution in the first bio-oxidation step, and a high redox potential benefited the bio-oxidationprocess. With an increase in the redox potential of the solution, the As(III) concentration in thesolution was decreased. After the first step of the bio-oxidation process, only 4.38% of the arsenicremained in the residue when the slurry density was 7%. After the second step of the bio-oxidationprocess, the arsenic content in the residue was decreased to 1.81% when the slurry density for thesecond step of the bio-oxidation process was 14%. Cyanidation tests indicate that the leaching rate ofgold could reach 95.66% after sequential two-step bio-oxidation; this leaching rate was much higherthan that of the direct cyanidation and one-step bio-oxidation pretreatment.
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