Equilibrium distribution of Pb between copper metal and slags

The distribution ratio of Pb (LPbs/m) between three types of slags (FeOx–SiO2, CaO–FeOx and FeOx–CaO–SiO2) and molten copper after equilibrium was measured at 1300°C and oxygen partial pressure (pO2) of 10-10–10-6 atm. Results showed that for FeOx–SiO2 slag, the LPbs/m increased from 0.024 to 2.57 with pO2 increased from 10-10 to 10-6 atm. The LPbs/m with CaO–FeOx slag was lower than the FeOx–SiO2 slag at the same pO2, ranging between 0.015 and 0.53. Using the FeOx–CaO– SiO2 slag generated LPbs/m values (0.02–1.6) in between. The oxygen partial pressure in the investigated range had no obvious effect on the activity coefficient of PbO (γPbO) which was averagely 0.44, 1.70 and 0.71 for FeOx–SiO2, CaO–FeOx and FeOx–CaO–SiO2 slags, respectively. The increases in the (CaO+MgO)/SiO2 mass ratio of the FeOx–CaO–SiO2 slag induced the decrease in the LPbs/m and the increase in the γPbO value. However, the variation in the Fe/SiO2 mass ratio didn’t exert obvious effects.