Method for producing granular polysilicon

Patent metadata

Field	Value
Publication number	US-10118830-B2
Application number	US-201415109556-A
Country	US
Kind code	B2
Filing date	Dec 11, 2014
Priority date	Jan 8, 2014
Publication date	Nov 6, 2018
Grant date	Nov 6, 2018

Abstract

Segregation of silicon granules in the fluidized bed production of polycrystalline silicon is achieved by successively transferring granular polycrystalline silicon through a plurality of vessels designed for funnel flow of granular material. The transfers may occur prior to introduction of feed particles into the reactor, or the enlarged granules from the reactor may be thus transferred to improve product size uniformity.

First claim

The invention claimed is:

1. A process for avoiding particle segregation by size in the handling of granular polysilicon after production of the granular polysilicon by a process comprising: fluidizing silicon particles by means of a gas flow in a fluidized bed which is heated to a temperature of 850-1100° C. by means of a heating apparatus, adding a silicon-containing reaction gas and depositing silicon on the silicon particles, and withdrawing granular polysilicon from the fluidized bed reactor, and before packing the granular polysilicon, transferring the granular polysilicon by means of a plurality of successive conical vessels designed for funnel flow, and wherein at least one of the plurality of vessels comprises filling distributor cones consisting of silicon of coated or lined with silicon, installed in at least one of the plurality of vessels.

2. The process of claim 1 , wherein at least one of the plurality of vessels comprise an emptying funnel, an emptying tube or a binsert, each of which consists of silicon or is coated or lined with silicon.

3. The process of claim 1 , wherein the silicon particles on which silicon is deposited in order to produce granular polysilicon are produced by grinding silicon and classifying by screening, wherein the silicon particles are transferred by means of a plurality of successive vessels designed for funnel flow between production of the silicon particles and supply of the silicon particles in the reactor.

Assignees

• Wacker Chemie Ag

Inventors

• Hauswirth Rainer
• Enggruber Robert

Classifications

• B05D1/22

  using fluidised-bed technique (fluidised-bed technique in general B01J8/24) · CPC title

• C01B33/03 Primary

  by decomposition of silicon halides or halosilanes or reduction thereof with hydrogen as the only reducing agent · CPC title

• B01F5/247

  Operations & Transport · mapped topic

• B01F25/84

  Falling-particle mixers comprising superimposed receptacles, the material flowing from one to the other, e.g. of the sandglass type · CPC title

• C01B33/035 Primary

  by decomposition or reduction of gaseous or vaporised silicon compounds in the presence of heated filaments of silicon, carbon or a refractory metal, e.g. tantalum or tungsten, or in the presence of heated silicon rods on which the formed silicon is deposited, a silicon rod being obtained, e.g. Siemens process · CPC title