Abstract: Metallurgical silicon containing impurities of carbon and/or carbon-containing compounds is classified and subsequently used selectively for chlorosilane production. The process comprises the steps of: a) determining the free carbon proportion which reacts with oxygen up to a temperature of 700° C., b) directing metallurgical silicon in which the free carbon proportion is ?150 ppmw to a process for producing chlorosilanes and/or directing metallurgical silicon in which the free carbon proportion is >150 ppmw to a process for producing methylchlorosilanes. As a result of the process, metallurgical silicon having a total carbon content of up to 2500 ppmw can be used for producing chlorosilanes.

Abstract: A process for removing an impurity from a mixture containing at least one chlorosilane and/or organochlorosilane and at least one impurity from the group comprising a boron compound, a phosphorus compound, and an arsenic compound is provided. The process includes contacting the liquid mixture with an unfunctionalized organic polymer having pores with an average pore diameter of less than 50 ?, the average pore diameter being determined in accordance with DIN ISO 66134, and optionally removing the unfunctionalized organic polymer.

Abstract: Boron, phosphorus, arsenic, antimony and other impurities are at least partially removed from a mixture containing at least one chlorosilane and/or organochlorosilane by a) contacting the liquid mixture with a carrier material functionalized with an amidoxime of the general structural formula (I), where CAR=carrier material and R1, R2 are independently of one another H, alkyl, alkenyl, aryl, alkylaryl; and b) optionally removing the functionalized carrier material.

Abstract: A process for obtaining hexachlorodisilane and uses for the same. The process includes contacting at least one partially hydrogenated chlorodisilane of general formula HxSi2Cl(6-x) where x is from 1 to 5 in the liquid state with a solid non-functionalized adsorber material that is selected from the group comprising silicates, aluminosilicates, organic polymer and/or combinations thereof. The process also includes optionally separating the hexachlorodisilane and/or optionally separating the adsorber material.

Abstract: Generally unusable or difficultly useable dusts of ultrahigh purity silicon can be used to produce chlorosilanes under reasonable reaction conditions by employing a catalyst containing one or more of Co, Mo, W. The process may be incorporated into an integral plant for the production of polycrystalline silicon.

Abstract: The invention relates to a process for hydrogenating silicon tetrachloride in a reactor, wherein a reactant gas containing hydrogen and silicon tetrachloride is heated to a temperature between 850° C. and 1600° C. by means of at least one heating element, which comprises a graphite surface, wherein the temperature of the heating element is between 850° C. and 1600° C. The process is characterized in that a nitrogen compound is added to the reactant gas in a substance amount fraction of 0.1 to 10% based on hydrogen.

Abstract: Metallurgical silicon containing impurities of carbon and/or carbon-containing compounds is classified and subsequently used selectively for chlorosilane production. The process comprises the steps of: a) determining the free carbon proportion which reacts with oxygen up to a temperature of 700° C., b) directing metallurgical silicon in which the free carbon proportion is ?150 ppmw to a process for producing chlorosilanes and/or directing metallurgical silicon in which the free carbon proportion is >150 ppmw to a process for producing methylchlorosilanes. As a result of the process, metallurgical silicon having a total carbon content of up to 2500 ppmw can be used for producing chlorosilanes.

Abstract: Generally unusable or difficultly useable dusts of ultrahigh purity silicon can be used to produce chlorosilanes under reasonable reaction conditions by employing a catalyst containing one or more of Co, Mo, W. The process may be incorporated into an integral plant for the production of polycrystalline silicon.

Abstract: Separation of chlorosilane mixtures containing boron, arsenic, and/or phosphorus impurities is facilitated by a distillative separation using at least one divided column, with recycle streams to a first column being passed through an external absorbent for the impurities.

Abstract: Separation of chlorosilane mixtures containing boron, arsenic, and/or phosphorus impurities is facilitated by a distillative separation using at least one divided column, with recycle streams to a first column being passed through an external absorbent for the impurities.

Abstract: Separation of chlorosilane mixtures containing boron, arsenic, and/or phosphorus impurities is facilitated by a distillative separation using at least one divided column, with recycle streams to a first column being passed through an external absorbent for the impurities.

Abstract: The composition of a gas or gas stream containing AlCl3 in a chemical reactor is measured by removing AlCl3 from the gas and analyzing the gas by gas chromatography or spectroscopy. Chlorosilanes may be prepared in a fluidized bed reactor having a reactor height H0, in which supplied HCl reacts with silicon, wherein a temperature profile in the fluidized bed reactor is greater than S1(H/H0)=(a1?b1)*(1/(1+exp(?c1((H/H0)?d1))))+b1 and less than S2(H/H0)=(a2?b2)*(1/(1+exp(?c2((H/H0)?d2))))+b2, where a1=100° C., a2=300° C., b1=300° C., b2=400° C., c1=50, c2=20, d1=0.2, and d2=0.8.

Abstract: Separation of chlorosilane mixtures containing boron, arsenic, and/or phosphorus impurities is facilitated by a distillative separation using at least one divided column, with recycle streams to a first column being passed through an external absorbent for the impurities.

Abstract: The invention provides a process for endothermic gas phase reaction in a reactor, in which reactant gases are introduced into the reactor via a gas inlet apparatus and distributed homogeneously into a heating zone by means of a gas distribution apparatus, wherein the reactant gases are heated in the heating zone to a mean temperature of 500-1500° C. by means of heating elements and then conducted into a reaction zone, the reactant gases reacting in the reaction zone to give a product gas which is conducted out of the reactor via a gas outlet apparatus. Further subject matter of the invention relates to a process for endothermic gas phase reaction in a reactor, wherein the heating of the heating elements is controlled by temperature measurements in the reaction zone, at least two temperature sensors being present in the reaction zone for this purpose, and reactor for performance of the process.

Abstract: A process for hydrogenating chlorosilanes in a reactor, wherein at least two reactant gas streams are introduced separately from one another into a reaction zone, wherein the first reactant gas stream comprising silicon tetrachloride is conducted via a first heat exchanger unit in which it is heated and is then conducted through a heating unit which heats it to a first temperature before the first reactant gas stream reaches the reaction zone, and wherein the second reactant gas stream comprising hydrogen is heated by a second heat exchanger unit to a second temperature, wherein the first temperature is greater than the second temperature, and then introduced into the reaction zone, such that the mixing temperature of the two reactant gas streams in the reaction zone is between 850° C. and 1300° C.

Abstract: The composition of a gas or gas stream containing AlCl3 in a chemical reactor is measured by removing AlCl3 from the gas and analyzing the gas by gas chromatography or spectroscopy. Chlorosilanes may be prepared in a fluidized bed reactor having a reactor height H0, in which supplied HCl reacts with silicon, wherein a temperature profile in the fluidized bed reactor is greater than S1(H/H0)=(a1?b1)*(1/(1+exp(?c1((H/H0)?d1))))+b1 and less than S2(H/H0)=(a2?b2)*(1/(1+exp(?c2((H/H0)?d2))))+b2, where a1=100° C., a2=300° C., b1=300° C., b2=400° C., c1=50, c2=20, d1=0.2, and d2=0.8.

Abstract: The invention relates to a process for purifying chlorosilanes by distillation, which includes providing a boron-containing mixture of chlorosilanes containing TCS, DCS and STC and purifying the mixture of chlorosilanes by distillation in a plurality of distillation columns, wherein low-boiling boron compounds are branched off from the distillation columns by overhead streams containing boron-enriched DCS and high-boiling boron compounds are branched off by a boron-enriched bottom stream containing high boilers.

Abstract: The invention provides a process for hydrogenating silicon tetrachloride in a reactor, in which reactant gas containing hydrogen and silicon tetrachloride is heated to a temperature of greater than 900° C. at a pressure between 4 and 15 bar, first by means of at least one heat exchanger made from graphite and then by means of at least one heating element made from SiC-coated graphite, the temperature of the heating elements being between 1150° C. and 1250° C., wherein the reactant gas includes at least one boron compound selected from the group consisting of diborane, higher boranes, boron-halogen compounds and boron-silyl compounds, the sum of the concentrations of all boron compounds being greater than 1 ppmv based on the reactant gas stream.

Abstract: The invention provides a process for endothermic gas phase reaction in a reactor, in which reactant gases are introduced into the reactor via a gas inlet apparatus and distributed homogeneously into a heating zone by means of a gas distribution apparatus, wherein the reactant gases are heated in the heating zone to a mean temperature of 500-1500° C. by means of heating elements and then conducted into a reaction zone, the reactant gases reacting in the reaction zone to give a product gas which is conducted out of the reactor via a gas outlet apparatus. Further subject matter of the invention relates to a process for endothermic gas phase reaction in a reactor, wherein the heating of the heating elements is controlled by temperature measurements in the reaction zone, at least two temperature sensors being present in the reaction zone for this purpose, and reactor for performance of the process.

Abstract: A process for hydrogenating chlorosilanes in a reactor, wherein at least two reactant gas streams are introduced separately from one another into a reaction zone, wherein the first reactant gas stream comprising silicon tetrachloride is conducted via a first heat exchanger unit in which it is heated and is then conducted through a heating unit which heats it to a first temperature before the first reactant gas stream reaches the reaction zone, and wherein the second reactant gas stream comprising hydrogen is heated by a second heat exchanger unit to a second temperature, wherein the first temperature is greater than the second temperature, and then introduced into the reaction zone, such that the mixing temperature of the two reactant gas streams in the reaction zone is between 850° C. and 1300° C.