The Calculation for Saturated Solubility of Oxygen in Mn–Si Melts Equilibrated with MnO–SiO2 Slags

The MnO–SiO2 slag in equilibrium with Mn–Si melts with a Si molar ratio between 0.1 and 0.3 at 1,700 K was a single liquid phase. However, it was liquid phase saturated with solid MnO or solid SiO2 in the case of XSi less than 0.1 or greater than 0.3, respectively. Based on a subregular solution model, the calculated saturated solubility of oxygen in Mn–Si melts was 0.0236 mass % in pure manganese at 1,700 K and increased with the increasing silicon in the range of XSi from 0.1 to 0.3. However, the saturated solubility of oxygen decreases as the silicon exceeded 0.3, and the minimum solubility was 0.0041 mass % in pure silicon at 1,700 K. The results could be used to predict the compositions of endogenous oxide inclusions and evaluate the cleanliness of manganese ferroalloy.