Influence of copper minerals on cyanide leaching of gold

Abstract

The paper thermodynamically examined the behavior of various copper minerals in cyanide solutions and investigated the influence of copper minerals on cyanide leaching of gold. In elucidating the influence of copper minerals on cyanide leaching of gold, copper minerals were classified into two types according to their solubility in cyanide solutions by proposing two concepts, cyaniding easily soluble copper (E_Cu) and cyaniding insoluble copper. The former involves copper occurrence in metal, oxides and secondary sulfides, and the latter refers mainly to primary sulfides. Experimental results show that not all the total copper in an ore affected cyanide leaching of gold, while cyaniding easily soluble copper turns out to be the decisive factor that interferes with gold cyanidation by causing decrease in gold cyanidation recovery and increase in cyanide consumption. When cyaniding easily soluble copper content (w_E(Cu)) lies in the range of 0–0.25%, it linearly affects gold cyanidation recovery (R) as well as cyanide consumption (m_c). The regression equations have been worked out to be R(%)=94.177 5−142.735 7 w_E(Cu) with a correlation coefficient of −0.902 and m_c=5.590 7 +33.572 9 w_E(Cu) with a correlation coefficient of 0.945, respectively.

Keywords

copper mineral / gold / cyanidation / leaching

References

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