# US 10,118,829 B2 · Processes for producing silicon

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- Number: US 10,118,829 B2
- Document ID: US10118829B2
- Status: Granted
- Kind: B2
- Application number: 15/521,044
- Filed: 2016-10-24
- Published: 2017-11-23
- Granted: 2018-11-06
- Earliest claimed: 2015-10-29
- Assignees: Wacker Chemie AG
- Applicants: Wacker Chemie AG
- Inventors: Peter Gigler; Juergen Stohrer
- Web page: https://patentgrep.com/patent/US10118829B2

## CPC

- C01B 33/023: by reduction of silica or {free} silica-containing material
- C01P 2006/80: Compositional purity
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

Silicon is produced by magnesiothermic reduction of silicon dioxide, wherein to achieve magnesiothermic reduction a reactant mixture is employed which contains silicon dioxide (SiO2) and magnesium (Mg) and, as moderators, magnesium oxide (MgO) and silicon (Si), and optionally further moderators.

## Claims

### Claim 1

A process for producing silicon by magnesiothermic reduction of silicon dioxide, comprising providing a reactant mixture comprising silicon dioxide and reducing silicon dioxide with magnesium in the presence of magnesium oxide and silicon as primary moderators, and optionally one or more further moderators.

### Claim 2 (depends on 1)

The process of claim 1, wherein the reactant mixture comprises 45 to 95 wt % of magnesium oxide based on the total weight of all moderators.

### Claim 3 (depends on 1)

The process of claim 1, wherein the reactant mixture comprises 5 to 55 wt % of silicon based on the total weight of all moderators.

### Claim 4 (depends on 2)

The process of claim 2, wherein the reactant mixture comprises 5 to 55 wt % of silicon based on the total weight of all moderators.

### Claim 5 (depends on 1)

The process of claim 1, wherein a mixture obtained by a magnesiothermic reduction of silicon dioxide is employed at least in part as a moderator.

### Claim 6 (depends on 1)

The process of claim 1, wherein the weight ratio of silicon dioxide and magnesium to the moderators is 0.05 to 1.

### Claim 7 (depends on 1)

The process of claim 1, wherein the product mixture obtained by magnesiothermic reduction comprises 3 to 40 wt % of silicon, 45 to 95 wt % of magnesium oxide and optionally 0 to 40 wt % of further constituents, wherein the wt % values are in each case based on the total weight of the product mixture and for each product mixture sum to 100 wt %.

### Claim 8 (depends on 1)

The process of claim 1, wherein the magnesiothermic reduction is a batch process or a recycle process.

### Claim 9 (depends on 8)

The process of claim 8, wherein the product mixture obtained in the recycle process is fully or partly introduced into the reactant mixture.

### Claim 10 (depends on 9)

The process of claim 9, wherein 50 to 95 wt % of the product mixture obtained in the recycle process is introduced into the reactant mixture as a moderator.

### Claim 11 (depends on 9)

The process of claim 9, wherein 70 to 100 wt % of the moderators are employed in the form of a product mixture.