A method for efficiently producing polysilicon is realized. The present invention is an invention of a method for producing polysilicon by the Siemens process, a chemical reactor being connected to a waste gas processing facility via a blocking valve provided to a waste gas pipe, the blocking valve being provided in a vicinity of a waste gas outlet of the chemical reactor, the method including the step of cooling a waste gas between the waste gas outlet of the chemical reactor and the blocking valve, with use of a cooler of an indirect cooling type.

A method for efficiently producing polysilicon is realized. The present invention is an invention of a method for producing polysilicon by the Siemens process, a chemical reactor being connected to a waste gas processing facility via a blocking valve provided to a waste gas pipe, the blocking valve being provided in a vicinity of a waste gas outlet of the chemical reactor, the method including the step of cooling a waste gas between the waste gas outlet of the chemical reactor and the blocking valve, with use of a cooler of an indirect cooling type.

A method for preventing contamination of a base plate having a step of, after producing polycrystalline silicon in a reactor having the base plate and a lid covering the base plate, removing the lid from the base plate; and a step of isolating space including the base plate by an isolation device.

A method for preventing contamination of a base plate having a step of, after producing polycrystalline silicon in a reactor having the base plate and a lid covering the base plate, removing the lid from the base plate; and a step of isolating space including the base plate by an isolation device.

Particulate composite materials and devices comprising the same are provided.

Particulate composite materials and devices comprising the same are provided.

Deposition on a sightglass in a reactor for CVD deposition of silicon is reduced by conducting a first purge gas stream substantially parallel to the reactor end surface of the sightglass, and conducting a second purge gas stream within the sightglass tube at an angle from the sightglass surface toward the interior of the reactor.

Deposition on a sightglass in a reactor for CVD deposition of silicon is reduced by conducting a first purge gas stream substantially parallel to the reactor end surface of the sightglass, and conducting a second purge gas stream within the sightglass tube at an angle from the sightglass surface toward the interior of the reactor.

Reflective silver coatings on the inside surfaces of a Siemens reactor for polycrystalline silicon production are improved by a cold forming after-treatment of the silver coating.

Reflective silver coatings on the inside surfaces of a Siemens reactor for polycrystalline silicon production are improved by a cold forming after-treatment of the silver coating.