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

A. N. Fedorov, Professor, e-mail: fedorov_a_n@mail.ru

Satbayev University, Almaty, Kazakhstan:
N. K. Dosmukhamedov, Associated Professor
E. E. Zholdasbay, Researcher

This paper describes general regularities and peculiarities of how copper dissolves in the Cu₂O – FeO_х – SiO₂ – CaO – Al₂O₃ system depending on the slag composition. The authors looked at how copper solubility in slag depends on the concentration of СаО in the slag. The authors found that a higher concentration of СаО would at first lead to a reduced solubility of copper oxide in the slag. However, after passing a certain minimum, the solubility would rise again. All the temperatures studied have minimum values of the copper oxide solubility, which correspond to the CaO/SiO₂ ratio = 0.7–0.85. Equations of pair and multiple correlation were constructed, which can help adequately predict the concentration of dissolved copper oxide and the slag viscosity depending on the slag composition typical of the direct production of Bessemer copper. The authors calculated the basicity coefficients of slag, which allow for the combined effect of the basic components of the slag system on viscosity. The authors found that as the concentration of copper oxide rises, the viscosity of the Cu₂O – FeO_х – SiO₂ – CaO – Al₂O₃ system also rises. The presence of copper boosts the basicity of the system. On the basis of the slag viscosity data obtained, the following interface regions of the ternary system were formulated and recommended, % (wt): 20–25 SiO₂; 35–45 FeO; 10–15 CaO. Due to this, the mean coefficients of the FeO/SiO₂ and CaO/SiO₂ ratios can be maintained at 1.8 and 0.7, thus ensuring optimum viscosity of slag (μ = 0.3–0.5 Pa·s) and minimum solubility of copper oxide in slag at the working temperature of 1250 ^oC.

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