Copper solubility in SiO2-CaO-FeOx slag equilibrated with matte

Abstract

The main focus in this paper is the determination of copper solubility in SiO2-CaO-FeOx slag equilibrated with copper matte under 10% SO2 atmosphere at 1573K. Essential parameters are: activity coefficients of copper oxide and sulfide, oxygen and sulfur potentials and activity of copper in the slag-matte system. A large number of experiments provides proper parameters to calculate copper solubility in slag. A classical thermodynamic model postulating CuO0.5 and CuS0.5 molecules assists in estimating copper solubility in slag. Additions of SiO2 and CaO reduce copper solubility in almost any condition. Copper loss, that is function copper solubility and slag volume, in the silica saturated SiO2-FeOx binary slag is minimally equilibrated with less than 66% copper matte while copper loss in the 50% FeOx-SiO2-CaO ternary slag saturated with 2CaO-SiO2 is minimally equilibrated with over 66% copper matte. This slag composition has potential for continuous copper converting, direct copper production or high-grade matte production.