Empirical Activation Energies of MnO and SiO₂ Reduction in SiMn Slags Between 1500 and 1650 °C

Abstract

The reduction rates of MnO and SiO₂ were investigated for various charge compositions. The empirical activation energies of MnO and SiO₂ reduction from SiMn slags were calculated between 1500 and 1650 °C under CO atmospheric pressure. The amounts of metal produced at different temperatures were compared, and the Arrhenius plots were described for each slag A, slag B and synthetic slag, which shows that the raw material have significant influence on the reduction rate. The rate of Mn-produced in slag A was faster than slag B despite of the relatively lower driving force. The lower rate constant in slag B implies that other kinetic factors, such as viscosity, affects the reduction rate. The estimated activation energies of MnO were 920, 304 and 975 kJ/mol MnO for slag A, slag B and synthetic slag, respectively. The rates of Si-produced were similar and slow for all slag types. However, the different activation energies of SiO₂ between industrial ores and synthetic materials implied that the trace elements can have catalytic effects toward SiO₂ reduction in SiMn slags. The estimated activation energies of SiO₂ reduction were around 800 kJ/mol for slag A and slag B.