Method for producing chlorosilanes

Patent metadata

Field	Value
Publication number	US-11845667-B2
Application number	US-201817048304-A
Country	US
Kind code	B2
Filing date	Apr 18, 2018
Priority date	Apr 18, 2018
Publication date	Dec 19, 2023
Grant date	Dec 19, 2023

Abstract

Chlorosilanes of the general formula H n SiCl 4-n and/or H m Cl 6-m Si 2 , where n=1-4 and m=0-4, are produced in a fluidized bed reactor by reaction of a hydrogen chloride-containing reaction gas with a silicon contact mass granulation mixture composed of a coarse grain fraction and a fine grain fraction, wherein the average particle size of the fine grain fraction d 50,fine is smaller than the average particle size of the coarse grain fraction d 50,coarse .

First claim

The invention claimed is:

1. A process for producing chlorosilanes of the general formula H n SiCl 4-n and/or H m Cl 6-m Si 2 , where n=1-4 and m=0-4, in a fluidized bed reactor, comprising:
reacting a hydrogen chloride-containing reaction gas with a contact mass which comprises silicon as a granulation mixture composed of a coarse grain fraction and a fine grain fraction, wherein the average particle size of the fine grain fraction d 50,fine is 5 to 400 μm and the average particle size of the coarse grain fraction d 50,coarse is 125 to 600 μm, with the proviso that d 50,fine is smaller than d 50,coarse and the difference d 50,coarse −d 50,fine is greater than 1 μm, wherein d 50,fine and d 50,coarse are present in a grain size ratio d 50,fine /d 50,coarse of 0.02 to 0.9, the fine grain fraction and the coarse grain fraction are present in a mass ratio m(fine)/m(coarse) of 0.05 to 20, and wherein the granulation mixture has a span of particle size distribution d 90 −d 10 /d 50 of 1 to 100.

2. The process of claim 1 , wherein the granulation mixture has a p-modal, volume-weighted distribution density function, where p=1 to 10.

3. The process of claim 1 , wherein the granulation mixture has a p-modal, volume-weighted distribution density function, where p=1 to 3.

4. The process of claim 1 , wherein d 50,fine and d 50,coarse are present in a grain size ratio d 50,fine /d 50,coarse of 0.03 to 0.7.

5. The process of claim 1 , wherein the fine grain fraction and the coarse grain fraction are present in a mass ratio m(fine)/m(coarse) of 0.09 to 10.

6. The process of claim 1 , wherein the fine grain fraction and the coarse grain fraction are present in a mass ratio m(fine)/m(coarse) of 0.09 to 4.

7. The process of claim 1 , wherein the granulation mixture has a span of particle size distribution d 90 −d 10 /d 50 of 1.5 to 10.

8. The process of claim 1 , wherein the silicon is metallurgical silicon and ultrahigh purity silicon, wherein the proportion of metallurgical silicon is at least 50% by weight, based on the total weight of the contact mass.

9. The process of claim 8 , wherein the ultrahigh purity silicon is a constituent of the fine grain fraction.

10. The process of claim 1 , wherein the silicon is metallurgical silicon and ultrahigh purity silicon, wherein the proportion of metallurgical silicon is less than 50% by weight and the granulation mixture additionally contains a catalyst.

11. The process of claim 10 , wherein the ultrahigh purity silicon and/or the catalyst are constituents of the fine grain fraction.

12. The process of claim 1 , wherein the silicon is ultrahigh purity silicon and the granulation mixture contains a catalyst.

13. The process of claim 1 , wherein the silicon is ultrahigh purity silicon and the granulation mixture contains a catalyst, wherein the catalyst is a constituent of the fine grain fraction.

14. The process of claim 1 , wherein the fine grain fraction and the coarse grain fraction are supplied to the fluidized bed reactor as a pre-prepared granulation mixture.

15. The process of claim 1 , wherein the fine grain fraction and the coarse grain fraction are each supplied to the fluidized bed reactor separately.

16. The process of claim 1 , wherein a quotient of fluidized bed height to reactor diameter is 10:1 to 1:1.

17. The process of claim 1 , wherein a quotient of fluidized bed height to reactor diameter is 6:1 to 3:1.

18. The process of claim 1 , wherein the chlorosilanes are selected from the group comprising monochlorosilane, dichlorosilane, trichlorosilane, Si 2 Cl 6 , HSi 2 Cl 5 , and mixtures thereof.

19. The process of claim 1 , which is integrated into an integrated system for producing polycrystalline silicon.

Assignees

• Wacker Chemie Ag

Inventors

• Rimboeck Karl-Heinz
• Sofina Natalia

Classifications

• C01B33/10742 Primary

  prepared by hydrochlorination of silicon or of a silicon-containing material · CPC title

• B01J8/24

  according to "fluidised-bed" technique (B01J8/20 takes precedence) · CPC title

• C01P2004/51

  Particles with a specific particle size distribution · CPC title

• C01P2006/10

  Solid density · CPC title

• C01P2006/80

  Compositional purity · CPC title