The rates of MnO reduction from slag by carbon saturated iron and Cu-Si alloy have been measured in the temperature range from 1500°C to 1600°C and the rate controlling steps have been determined by an electrochemical consideration.
The results obtained are as follows:
1. Apparent activation energies of MnO reduction by carbon saturated iron are about 120, 80 and and 73kcal/mol for 40CaO50SiO₂10Al₂O₃+4.O3Mn0 (slag A), 50CaO40SiO₂10Al₂O₃+3.9Mn0 (Slag B), and 50CaO50Al2O3+2.3Mn0 (wt%)(slag C), respectively.
2. The rate of MnO reduction is promoted by the addition of Si to carbon saturated iron or Cu but is not increased by the addition of Si beyond 5wt%, and its rate coefficient is K_m=180×10^-5 (g/cm²-min) for a slag B at 1510 deg;C.
3. The rate controlling step of MnO reduction by carbon saturated iron containing small amounts of Si is an anodic reaction of CO evolution and that by carbon saturated iron or Cu-Si alloy containing Si above 5 wt% is Mn diffusion in slag.