Theoretical Analysis and Experimental Study of Extraction of Magnesium from Dolomite by Smelting Reduction

Theory of the silicothermic smelting reduction of MgO by Si was analyzed and experiments of smelting reduction were carried out in molten slag of the compositon 53.95 % calcined dolomite, 33.95%Al₂O₃, 9.70%SiO₂、3.00%CaF₂ under vacuum. By thermodynamic analysing, the reduction temperature of liquid MgO react with liquid Si dropped from 2160K to1723K when the system pressure reduced from 1atm to 0.5×10⁴Pa. The results of experiments show that reduction extent of MgO is achieved up to 91.4 % with 1X silicon stoichiometry at 1873 K for 60min.