The equilibrium distribution coefficients of lead between the matte, slag and metallic phases in the silica-saturated, copper smelting system were determined. These experiments were carried out by simultaneously equilibrating the various phases in silica crucibles at 1300℃. The conditions investigated in this study ranged from iron and copper alloy saturation at low oxygen potentials to a sulfur dioxide partial pressure of 0.1 atm and up to a matte grade of 75 wt. % Cu. The lead was found primarily in matte except in the presence of the copper alloy phase. The accumulation of lead in the copper alloy phase was pronounced, particularly at low oxygen potentials. Under conventional smelting conditions, the lead content in slag increased with increasing matte grade. The behaviour of lead was explained by proposing metallic and sulfidic species in matte and oxidic and sulfidic dissolution in slag. In this manner, the activity coefficients of the various species were calculated in their respective phases
