Abstract: A process for preparing silanes of the formula 1: RaSiHbCl4-a-b  (1) where R is methyl or ethyl, a is 0, 1, 2 or 3 and b is 0 or 1, from hydrogen chloride gas and reactants selected from among a) silicon metal, b) disilanes and oligosilanes whose radicals are selected from among H, R and Cl,  and mixtures thereof, wherein the hydrogen chloride gas is prepared from H2 and Cl2 in a concerted process.

Abstract: A process for preparing silanes of the formula 1:

Abstract: A continuous process for the direct synthesis of silanes of the formula

Abstract: A continuous process for the direct synthesis of silanes of the formula 1 RaSiCl4−a  (1) involves reacting finely divided silicon metal with R—Cl in a fluidized bed, where R is hydrogen, methyl or ethyl and a is 0, 1, 2, 3 or 4, where a product stream comprising gaseous silanes of the formula 1, further gaseous reaction products, unreacted RCl and silicon-containing dust is discharged from the fluidized bed, wherein at least part of the dust is introduced in the form of a suspension in a liquid selected from among liquid silanes of the formula 1, further liquid reaction products and mixtures thereof, into the fluidized bed.

Abstract: Methylchlorosilanes are prepared by reacting methyl chloride with a contact catalyst which comprises silicon, copper catalyst, zinc promoters and tin promoters and/or antimony promoters, in which hydrogen chloride is added in the course of from 1% to 45% of the duration of the production campaign.

Abstract: In the direct synthesis of methylchlorosilanes by reacting methyl chloride with a catalyst composition which comprises silicon, copper catalyst, zinc promoters and tin promoters and/or antimony promoters, a catalyst composition is used which was activated in advance by treatment with HCl under specific activation conditions.

Abstract: In a process for the direct synthesis of methylchlorosilanes by reacting methyl chloride with a catalytic composition comprising silicon, copper catalyst and promoters, where at least some of the catalytic composition is comprised of the catalytic composition from a prior production campaign.

Abstract: Methylchlorosilanes are prepared by reaction of methyl chloride with silicon in the presence of a catalyst combination of copper oxide, zinc oxide and metallic antimony.

Abstract: Finely divided copper powder suitable for the preparation of copper catalyst for the synthesis of methylchlorosilane is prepared by adding an aqueous copper salt solution to an aqueous suspension of iron powder. Copper salt solutions obtained as process residues from the synthesis of methylchlorosilane can be used in the process of this invention.

Abstract: Organopolysiloxanes containing triorganosiloxy terminal units are obtained by a continuous process in which an organopolysiloxane mixture containing organo(poly)siloxanes having triorganosiloxy terminal units and cyclic organopolysiloxanes are introduced into a tube reactor that has been heated to at least 80.degree. C. and which contains a static catalyst bed. The organopolysiloxane composition containing triorganosiloxy terminal units, which exits from the tube reactor is different from the organo(poly)siloxanes containing triorganosiloxy terminal units which were introduced into the reactor. The contents of the reactor in the area between one-third and two-thirds of the distance between the point where the organopolysiloxanes are introduced into the tube reactor and the point where the organopolysiloxanes exit from the reactor, are maintained at a temperature which is at least 50.degree. C. below that which is immediately upstream from the outlet of the reactor.

Abstract: The invention relates to a process for treating elemental silicon and ferrosilicon with slag having the following analytical composition:______________________________________ K.sub.2 O from 2 to 13% by weight Na.sub.2 O from 0 to 2% by weight .SIGMA. K.sub.2 O + Na.sub.2 O from 2 to 13% by weight SiO.sub.2 from 45 to 72% by weight Al.sub.2 O.sub.3 from 0 to 30% by weight .SIGMA. SiO.sub.2 + Al.sub.2 O.sub.3 from 60 to 78% by weight CaO from 0 to 30% by weight MgO from 0 to 30% by weight .SIGMA. CaO + MgO from 15 to 30% by weight CaF.sub.2 from 0 to 10% by weight MgF.sub.2 from 0 to 10% by weight .SIGMA. CaF.sub.2 + MgF.sub.2 from 0 to 10% by weight .SIGMA. CaO + MgO + CaF.sub.2 + MgF.sub.2 from 15 to 30 % by weight ______________________________________and impurities resulting from the raw materials.

Abstract: A method for utilizing a residue containing elemental silicon in the form of particles having a maximum diameter of 50 microns which comprises heating the residue for at least 15 hours at a temperature of from 100.degree. to 350.degree. C. in the presence of atmospheric air and/or an inert gas and thereafter recycling the treated residue into a process for preparing halosilanes.

Abstract: A process for preparing trimethylchlorosilane which comprises reacting methyldichlorosilane with methyl chloride and metallic aluminum.

Abstract: A process of melting down and purifying silicon, which comprises melting silicon in at least half of the amount up to double of the amount of a silicate melt heated by resistance heating up to a temperature of at least 1,420.degree. C., said melt consisting of 2-30% by weight of calcium oxide, 5-35% by weight of magnesium oxide, wherein the sum of calcium oxide and magnesium oxide will be 15-38% by weight, 0.5-28% by weight of aluminum oxide and 45-70% by weight of silicon dioxide, and wherein, to the melt are added at least 0.29% by weight of elementary and/or chemically bound copper, preferably 0.50-3% by weight, calculated on the silicon amount.