MISiS National University of Science and Technology, Moscow, Russia:

А. А. Komkov, Associate Professor at the Department of Non-Ferrous Metals and Gold, e-mail: akomkov@yandex.ru
V. I. Karyaev, Postgraduate Student at the Department of Non-Ferrous Metals and Gold, e-mail: karyaev@mailnord.ru

LLC “BASF”, Moscow, Russia:
R. I. Kamkin, Head of the Technical Centre in Russia and CIS, e-mail: rostislav.kamkin@basf.com

LLC “Nord Engineering”, Moscow, Russia:
A. V. Kuznetsov, Technical Director, e-mail: kuznetsov@mailnord.ru

This paper describes an experimental study of the kinetics and essence of copper losses during gas flush reduction of copper smelter slags. The paper contains experimental data and the results of related calculations that show how the copper reduction rate changes during gas flush reduction of copper smelter slags with gas mixtures characterized by different CO/CO₂ ratios. The actual values obtained, which indicate how much copper remained in the slags after reduction, were compared with the copper content in the slags if the process is reversed, i.e. during copper saturation of slags. Consistent discrepancies were found, which cannot just be attributed to possible experimental error. The authors provide their suggestions of what could have caused the discrepancies. Based on the metallography data, it was established th at the main factor contributing to copper losses during gas flush reduction of copper smelter slags includes mechanical losses, which are attributed to the presence in the slag of a great number of suspended fine (3–4 μm) particles of the alloy with a composition identical to the bottom metallic phase. The analysis showed that, during the experiments, mechanical losses accounted for 13 to 69% of total copper losses. The experimental data obtained (allowing for the mechanical losses) were compared with the values obtained through thermodynamic calculations of the slag reduction process based on the iron oxide activity values of 0.35 and 0.45, which are consistent with real copper smelter slags. The comparison indicated consistency between experimental and calculated values, which supports the supposition about mechanical losses being a major factor in the total copper losses with slags.

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