Thermochemical nature of arsenic, antimony and bismuth in copper smelting matte

The equilibrium distribution measurements of As, Sb and Bi between molten copper and white metal and molten copper and matte were conducted to evaluate the activity coefficients of these impurity elements in copper smelting matte. The experimental results were analyzed through comparison and reconciliation with data in the literature. The following equations, based on a liquid standard state, were obtained for gammaAs, gammaSb and gammaBi in white metal coexisting with copper phase at 1,150-1,200°C. Ln gammaAs = -2.49 + 0.186 NAs; Ln gammaSb = -1.23 + 23.5 NSb; Ln gammaBi = 3.01 + 14.0 NBi where Ni represents the mole fraction of the element i in white metal. Analysis of the data demonstrated that a major factor in removing As, Sb and Bi in matte during smelting involves careful control of the sulfur pressure, ie. matte's sulfur content, the optimum matte composition's being those that approach the Cu2S-FeS pseudo binary.