Abstract: A method and an apparatus for condensing to the liquid state vapors of a metal having a melting point of between 500.degree. and 850.degree. C. in a double envelope container. The pressures between the two faces of the inner envelope of the container are adjusted to be in equilibrium, and the outer face of the inner envelope is cooled in such a way as to keep the inner face temperature substantially constant in the vicinity of the solidification temperature of the metal. The invention is applicable in particular to condensing magnesium vapors.

Abstract: The invention relates to a silicon alloy intended for the production of alkyl or aryl halogenosilanes using the Rochow reaction, comprising, in percent by weight:0.05<Al<0.300.01<Ca<0.300.02<O.sub.2 <0.200.10<Fe<0.500.01<Ti<0.15x<Cu<2+xwhere x=3.2 (% Ca)+9.4 (% Al) the remainder being silicon. The alloy according to the invention makes it possible to improve the reactivity and the selectivity of the reaction.

Abstract: A process for recovery of magnesium from magnesium alloy waste by charging an electric furnace with a flux including at least one salt, the flux being inert with respect to magnesium and having a melting point <1000.degree. C. The flux is raised by the Joule effect at a reduced pressure to a temperature of 900.degree. to 1100.degree. C. to produce a bath having a density higher than that of magnesium, a vapor pressure <0.1 torr and an electrical resistivity of between 1 and 10 milliohm.m. The magnesium alloy waste is introduced in the bath, and magnesium and any other elements in the waste which are more volatile than magnesium are recovered from a vapor phase above the bath. Any elements in the waste which are less volatile than magnesium are recovered from a molten phase in a bottom portion of the furnace.

Abstract: Abrasive and/or refractory products comprising at least one compound from the group of oxynitrides of one or more metals or metalloids (such as Al, Mg, alkaline earth metals, Si, Ti or Zr) and obtained by melting and solidification.

Abstract: Process for direct nitriding of metals of relatively low melting point with the aid of a nitrogen-containing gas, in which a powder of at least one of the metals is mixed with a refractory powder, the mixture is heated under an atmosphere of nitrogen-containing gas at atmospheric pressure until the start of a rapid and exothermic nitriding reaction, and this reaction, which proceeds at a temperature generally higher than that of the melting point of the metals without apparent melting being observed, is allowed to proceed until all of the metals have been consumed, in order to obtain a highly porous solid mass which is easy to grind and is based on metal nitrides or metal oxynitrides.