SRC Hydrometallurgy (LLC), Saint Petersburg, Russia:

P. V. Zaytsev, Head of the Science and Technology Department, Сandidate of Technical Sciences, e-mail: zaytsev-p@gidrometall.ru
N. A. Kravchenko, Research Fellow, e-mail: kravchenko-n@gidrometall.ru

This paper describes the results of a study that looked at hydrometallurgical processing of bulk copper concentrates obtained from mixed copper ore. It is demonstrated that due to the use of pressure oxidation process for oxidation of copper concentrates (which implies harsher conditions compared with normal atmosphere, i.e. the temperature range of 180 to 230 ^oC and the partial oxygen pressure of 0,3 to 1 MPa), almost all the sulphides can be oxidized, including chalcopyrite, which demonstrates the strongest refractory properties. The pressure oxidation process has a much shorter duration. Thus, it can take from 10 to 40 minutes depending on the process parameters. Recovery of copper into solution reaches 99.5%. The mass fraction of elemental sulphur in the autoclave residues does not exceed 0.5%. Alkaline conditioning of fully oxidized autoclave residues followed by cyaniding helps recover silver at an approximate recovery rate of 87%, with the consumption of potassium cyanide not exceeding 10 kg/t residue.

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