Magnesiothermic reduction of tungsten and molybdenum oxide compounds

Abstract

A process of producing tungsten and molybdenum powders by magnesium vapor reduction of WO3, MoO3, MgWO4, MgMoO4, CaWO4, CaMoO4, and Ca3WO6 within the temperature range 700–800°C at a residual argon pressure of 5–15 kPa has been studied. The reduction of WO3, MoO3, MgWO4, MgMoO4, and CaMoO4 was accompanied by separation of the products in the reaction mixture, namely, by the removal of most of the resulting magnesium oxide from the reaction zone. Using tungsten and molybdenum compounds containing MgO or CaO as precursors, tungsten and molybdenum powders with a mesoporous structure and a specific surface area of 18–20 m2/g have been produced.