Method for producing silicon fragments

Patent metadata

Field	Value
Publication number	US-12172170-B2
Application number	US-201917639309-A
Country	US
Kind code	B2
Filing date	Aug 29, 2019
Priority date	Aug 29, 2019
Publication date	Dec 24, 2024
Grant date	Dec 24, 2024

Abstract

The present disclosure relates to a method for producing polycrystalline silicon fragments. The process includes (a) providing a polycrystalline silicon rod, (b) working the surface of the silicon rod by means of a hammer or needle hammer to remove at least a portion of a layer of the surface of the polycrystalline silicon rod, and (c) reducing the silicon rod to fragments. Wherein an amount of impact energy expended by the hammer and/or needle hammer is from 1 J to 15 J.

First claim

The invention claimed is:

1. A process for producing silicon chunks, comprising the steps of:
a) providing a silicon rod;
b) treating a surface of the silicon rod with a hammer and/or a needle hammer for at least partial removal of a silicon layer of the surface of the silicon rod;
c) comminuting the silicon rod into chunks using a thermal crushing process or a high-voltage impulse crushing or a jaw crusher, a roller crusher, a chisel or a sledgehammer apparatus; and
wherein the silicon layer of the surface of the silicon rod is removed to a depth of 1 to 10 mm by an impact energy applied with the hammer and/or needle hammer of 1 to 15 J.

2. The process of claim 1 , wherein the impact energy applied with the hammer and/or needle hammer is 2 to 10 J or wherein the impact energy applied with the hammer and/or needle hammer is 3 to 8 J.

3. The process of claim 1 , wherein the needle hammer comprises 6 to 24 needles, wherein the needle hammer comprises 6 to 18 needles, or wherein the needle hammer comprises 6 to 12, needles.

4. The process of claim 1 , wherein the needle hammer comprises needles; and
wherein the needles of the needle hammer each have a circular impact surface having a radius of 0.5 to 1.5 mm, or wherein the needles of the needle hammer each have a circular impact surface having a radius of 0.5 to 1 mm.

5. The process of claim 4 , wherein the needle hammer is operated with an impact speed of 2000 to 5000 min −1 , wherein the needle hammer is operated with an impact speed of 2500 to 4000 min −1 , or wherein the needle hammer is operated with an impact speed of 2800 to 3500 min −1 .

6. The process of claim 1 , wherein the needle hammer is an electrically, a pneumatically or a hydraulically operated needle hammer.

7. The process of claim 1 , wherein the needle hammer comprises needles; and
wherein the needles of the needle hammer and/or at least a polysilicon-contacting part of the hammer is made of a material selected from the group comprising carbide, metal-ceramic, ceramic and combinations thereof.

8. The process of claim 1 , wherein the needle hammer comprises needles; and
wherein the needles of the needle hammer and/or at least a polysilicon-contacting part of the hammer is made of tungsten carbide, tungsten carbide with a cobalt binder, tungsten carbide with a nickel binder, titanium carbide, chromium carbide with a nickel-chromium alloy binder, tantalum carbide, niobium carbide, silicon nitride, silicon carbide in a matrix, aluminum nitride, titanium carbide with cobalt and titanium carbonitride, nickel, nickel-cobalt alloy, iron and combinations thereof.

9. The process of claim 1 , wherein the silicon layer of the surface of the silicon rod is removed to the depth of 1 to 5 mm or wherein the silicon layer of the surface of the silicon rod is removed to the depth of 1 to 3 mm.

10. The process of claim 1 , wherein roughness parameters Ra and/or RPc according to DIN EN ISO 4287/4288 and DIN EN 10049 of the silicon rod are determined between steps a) and b) and/or between steps b) and c).

11. The process of claim 1 , wherein the step b) is repeated after a determination of the roughness of the treated silicon rod.

12. The process of claim 1 , wherein the silicon layer of the surface of the silicon rod at least partially removed is a surface layer of popcorn.

13. The process of claim 1 , wherein the silicon layer of the surface of the silicon rod at least partially removed is a surface layer of popcorn; and
wherein the popcorn layer of the surface of the silicon rod is removed to the depth of 1 to 5 mm or wherein the popcorn layer of the surface of the silicon rod is removed to the depth of 1 to 3 mm.

Assignees

• Wacker Chemie Ag

Inventors

• Vietz Matthias

Classifications

• B02C2201/00

  Codes relating to disintegrating devices adapted for specific materials · CPC title

• B02C1/10

  Shape or construction of jaws · CPC title

• B25D2250/291

  Tools having three or more parallel bits, e.g. needle guns · CPC title

• B25D2222/51

  Hard metals, e.g. tungsten carbide · CPC title

• B25D9/00

  Portable percussive tools with fluid-pressure drive, {i.e. driven directly by fluids}, e.g. having several percussive tool bits operated simultaneously {(portable non-percussive drilling tools driven by fluid pressure or pneumatic power B23B45/04)} · CPC title