1996 Volume 37 Issue 8 Pages 1431-1437
As a fundamental study for the oxygen-blowing copper smelting, the phase equilibrium between ferrite slag and copper matte was investigated at 1523 K under the partial pressures of SO2 controlled at 10.1, 50.7 and 101.3 kPa, using a sulfur reservoir for controlling the partial pressure of S2. An oxygen-sulfur potential diagram was constructed in relation to matte grade, and it was clarified that the ratio of (pO2⁄pS2) was constant against pSO2 when the matte grade was specified. The solubilities of copper and sulfur in the slag and calcium in the matte as well as (%Fe3+/%Fe2+) in the slag were also determined in relation to matte grade. The solubilities of copper and sulfur were found to be independent of pSO2 when the matte grade was specified and it was considered that this behavior was ascribable to the constancy of (pO2⁄pS2) against pSO2. The solubility of sulfur decreased gradually with increasing matte grade. On the other hand, the solubility of copper represented the minimum at matte grade with about 72.5 mass%Cu, which was analyzed thermodynamically based on a concept of oxidic and sulfidic dissolutions of copper component in the slag.
