Union Carbide Corporation

Union Carbide Chemicals & Plastics Technology Corporation

Osi Specialties, Inc.

William C Breneman

William C Crane

Eric A Warren

Michael J Walsh

Robert N Flagella

David W Hagan

Jon M Gaston

David M Reeser

Gunnar Henningsen

Chi-Cheng Yang

Andrew Green

Hiroshi Morihara

David Carter

A process for preparing an oil-in-water emulsion is provided, which process comprises mixing and heating a water-insoluble organomodified polysiloxane oil or an organic oil, an organomodified silicone emulsifier, water and an alkaline metal salt above the cloud point of the emulsifier under agitated conditions and cooling the resulting mixture below the cloud point.

Process for the emulsification of polydimethyl siloxane oils,

A process for preparing an oil-in-water emulsion is provided, which process comprises mixing and heating a water-insoluble organomodified polysiloxane oil, an organomodified silicone emulsifier, water and an alkaline metal salt above the cloud point of the emulsifier under agitated conditions and cooling the resulting mixture below the cloud point.

The present invention is directed to an improved process for producing ultra high purity polycrystalline silicon which process provides for increased production capacity and electrical power efficiency. The process comprises recycling the exhaust gases of the silane pyrolysis reactor after the gases have been preferably first cooled and filtered utilizing a pocket-type reaction zone enclosure having a particular effective radius thereby effectively decreasing the amount of silicon powder formation. Preferably, the rate of recycle flow is sufficient to entrain silicon powder in the reactor and remove the powder from the reactor with the exiting exhaust gases.

Process for the production of ultra high purity polycrystalline silicon

Method for treating waste slurries containing solid impurities, e.g. in the form of metal chlorides, and silicon tetrachloride and trichlorosilane by evaporation and separation techniques to recover more of the silicon tetrachloride and trichlorosilane.

Treatment of wastes from high purity silicon process

Method for treatment of contaminated chlorosilanes with lime to obtain an environmentally inept silica base product.

Disposal process for contaminated chlorosilanes

Silicon tetrachloride, hydrogen and metallurgical silicon are reacted at about 400.degree.-600.degree. C. and at pressures in excess of 100 psi, and specifically from about 300 up to about 600 psi to form di- and trichlorosilane that is subjected to disproportionation in the presence of an anion exchange resin to form high purity silane. By-product and unreacted materials are recycled, with metallurgical silicon and hydrogen being essentially the only consumed feed materials. The silane product may be further purified, as by means of activated carbon or cryogenic distillation, and decomposed in a fluid bed or free space reactor to form high purity polycrystalline silicon and by-product hydrogen which can be recycled for further use. The process results in simplified waste disposal operations and enhances the overall conversion of metallurgical grade silicon to silane and high purity silicon for solar cell and semiconductor silicon applications.

Growing community of inventors

Sistersville, WV, United States of America

William C Breneman