Wacker Chemie Ag

Uwe Paetzold

Michael Stepp

Walter Haeckl

Jan Prochaska

Karl-Heinz Rimboeck

Maximilian Aigner

Laszlo Fabry

Natalia Sofina

Robert Ring

Gerhard Traunspurger

Norbert Ellinger

Markus Niemetz

Andreas Hirschmann

Marek Sobota

Christian Schierlinger

Anton Reisbeck

Thorsten Goebel

Manfred Surner

Wolfgang Muenzer

Noemi Banos

Markus Kahler

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: As a result of the process, metallurgical silicon having a total carbon content of up to 2500 ppmw can be used for producing chlorosilanes.

Method of classifying metallurgical silicon

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.

Process for producing chlorosilanes using a catalyst selected from the group of Co, Mo, W

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.

Purification of chlorosilanes by means of distillation and adsorption

The composition of a gas or gas stream containing AlClin a chemical reactor is measured by removing AlClfrom 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&#x2212;b1)*(1/(1+exp(&#x2212;c1((H/H0)&#x2212;d1))))+b1 and less than S2(H/H0)=(a2&#x2212;b2)*(1/(1+exp(&#x2212;c2((H/H0)&#x2212;d2))))+b2, where a1=100&#xb0; C., a2=300&#xb0; C., b1=300&#xb0; C., b2=400&#xb0; C., c1=50, c2=20, d1=0.2, and d2=0.8.

Compositional analysis of a gas or gas stream in a chemical reactor and method for preparing chlorosilanes in a fluidized bed reactor

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&#xb0; 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.

Reactor and process for endothermic gas phase reaction in a reactor

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&#xb0; C. and 1300&#xb0; C., and said reactant gas streams react to give product gases comprising trichlorosilane and hydrogen chloride, wherein the product gases obtained in the reaction are conducted through said at least two heat exchanger units and preheat the reactant gas streams of the reaction by the countercurrent principle, wherein the flow passes first through the first heat exchanger unit and then through the second heat exchanger unit. A reactor for hydrogenating chlorosilanes, comprising two gas inlet devices through which reactant gases can be introduced separately from one another into the reactor, and at least one gas outlet device through which a product gas stream can be conducted, at least two heat exchanger units which are connected to one another and which are suitable for heating reactant gases separately from one another by means of the product gases conducted through the heat exchanger units, and a heating zone which is arranged between a first heat exchanger unit and a reaction zone and in which there is at least one heating element.

Process and apparatus for conversion of silicon tetrachloride to trichlorosilane

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.

Process for purifying chlorosilanes by distillation

Trichlorosilane production is increased while simultaneously lowering environmental burden due to destruction and disposition of high boilers by feeding high boilers from trichlorosilane production or from polycrystalline silicon production into a fluidized bed for production of trichlorosilane from metallic silicon and hydrogen chloride.

Recycling of high-boiling compounds within an integrated chlorosilane system

The invention relates to a method for hydrolyzing hydrolyzable solid metallic salts, wherein the metallic salts are reacted with aqueous saline solutions.

Method for hydrolyzing solid metallic salts with aqueous saline solutions

The invention relates to a method for hydrolyzing hydrolyzable metallic salts, the metallic salts being reacted with emulsions of a) water and b) an inert liquid.

Method for hydrolyzing metallic salts with emulsions

Highly pure pyrogenic silica is produced in an integrated polycrystalline silicon production plant by separating offgas from polycrystalline silicon production into a high boiler fraction, vaporizing this fraction into a pyrogenic silica burner and reacting with air and/or oxygen and hydrogen to form pyrogenic silica.

Process for recycling high-boiling compounds within an integrated chlorosilane system

Hydrogenation of a chlorosilane takes place in a reactor having a graphite reaction chamber with a surface which contacts the chlorosilane and a graphite electric heating element which also contacts the chlorosilane, wherein an Si-containing compound and hydrogen are contacted with the reaction chamber and the heating element such that an SiC coating is formed in situ on their surfaces in a first process step, and hydrogenation of the chlorosilane is effected by heating of a chlorosilane/hydrogen mixture in the reaction chamber by means of the heating element in a second process step, the first process step carried out at a reaction temperature which is higher than the reaction temperature of the second process step.

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Burghausen, Germany

Uwe Paetzold