GB741630A - Process for the production of metals by reduction of their halides - Google Patents

Abstract

Silicon is produced by introducing the vapour of a halide of silicon, having an absolute heat of formation not exceeding 70 kilogram calories per gram atom of halogen present in the halide, and the vapour of a reducing metal which is an alkali metal or magnesium in a single, constricted, vaporous stream into a reaction chamber which is evacuated or filled with an inert gas, igniting the stream and impinging the flame upon a collecting surface maintained at a temperature below the boiling point of the silicon and above the boiling point of the reducing metal halide. The reducing metal is preferably sodium. The silicon halide vapour and the reducing metal vapour may be introduced into the reaction chamber through a common nozzle opening, preceded by a mixing chamber, or through two concentric nozzles and additional heat may be supplied to the reaction by heating one or both reactants. The collecting surface may be concave and kept at a temperature above or below the melting point of the collected silicon or may be tubular and the silicon continuously discharged, e.g., in liquid form, from the reaction chamber. Alternatively, by controlled heat dissipation from the collecting surface, the surface only of the collected silicon may be kept molten and the solidified silicon continuously withdrawn from the chamber. Additional heat may be supplied to the collecting surface by electric gas discharge, e.g., an electric arc, the discharge also serving to heat the vaporous reactants. Separate auxiliary electrodes may be provided to maintain the arc or the common nozzle on the surface of the collected metal may be used as electrodes. The vaporous reducing metal halide may be condensed in the reaction chamber or after removal as vapour therefrom.ALSO:Metals, e.g. Ti, Zr, V, W and Mo, are produced by introducing the vapour of a halide of the metal, having an absolute heat of formation not exceeding 70 kilogram calories per gram atom of halogen present in the halide, and the vapour of a reducing metal which is an alkali metal or magnesium in a single, constricted, vaporous stream into a reaction chamber which is evacuated or filled with an inert gas, igniting the stream and impinging the flame upon a collecting surface maintained at a temperature below the boiling point of the required metal and above the boiling point of the reducing metal halide. The reducing metal is preferably sodium. The metal halide vapour and the reducing metal vapour may be introduced into the reaction chamber through a common nozzle opening, preceded by a mixing chamber, or through two concentric nozzles and additional heat may be supplied to the reaction by heating one or both reactants. The collecting surface may be concave and kept at a temperature above or below the melting point of the collected metal or may be tubular and metal continuously discharged, e.g. in liquid form, from the reaction chamber. Alternatively, by controlled heat dissipation from the collecting surface, the surface only of the collected metal may be kept molten and the solidified metal continuously withdrawn from the chamber. Additional heat may be supplied to the collecting surface by electric gas discharge, e.g. an electric arc, the discharge also serving to heat the vaporous reactants. Separate auxiliary electrodes may be provided to maintain the arc or the common nozzle or the surface of the collected metal may be used as electrodes. The vaporous reducing metal halide may be condensed in the reaction chamber or after removal as vapour therefrom. Using two or more metal halides, alloys may be produced and, using a silicon halide with one or more metal halides, alloys containing silicon may be produced.