Carbothermic reduction of calcium tungstate in the presence of various oxides

The possibility of reduction of calcium tungstate in an inert medium (in vacuum and argon) was investigated. As components involving WO 3 and B 2 O 3 , natural materials—namely, scheelite and datolite concentrates—were used. The main products of reduction are W 2 B 5 , WC, W 5 Si 3 , and SiC. The apparent activation energy of carbon diffusion in the carbide phase was evaluated based on the data of high-temperature X-ray powder diffraction and chemical analysis for certain tungstate systems. It was shown that reduction of scheelite concentrate could be carried out during electroslag remelting (ESR).