# US 12,110,232 B2 · Method for producing technical silicon

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- Number: US 12,110,232 B2
- Document ID: US12110232B2
- Status: Granted
- Kind: B2
- Application number: 17/598,412
- Filed: 2019-03-27
- Published: 2022-05-26
- Granted: 2024-10-08
- Earliest claimed: 2019-03-27
- Assignees: Wacker Chemie AG
- Applicants: Wacker Chemie AG
- Inventors: Karl-Heinz Rimboeck; Konrad Mautner
- Web page: https://patentgrep.com/patent/US12110232B2

## CPC

- C01B 33/037: Purification (by zone-melting C30B13/00)
- 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

Technical silicon is produced by heating a raw material mixture comprising particulate silicon metal-containing material and a particulate mediator containing at least one of C, O, Al, Ca and Si, to at least 1490° C., forming a liquid silicon phase, and solidifying this phase, wherein the raw material mixture a characteristic number K of from 0.000 to 60, calculated as follows: K = m ⁡ ( SiM ) · d ⁢ ⁢ 50 ⁢ ( SiM ) + m ⁡ ( Med ) · d ⁢ ⁢ 50 ⁢ ( Med ) m ⁡ ( SiM ) + m ⁡ ( Med ) · φ ( equation ⁢ ⁢ 1 ) where m (SiM) is the mass of the silicon metal-containing material in the batch m(Med) is the mass of the mediator d50,SiM is the mean particle size of the silicon metal-containing material, d50,Med is the mean particle size of the mediator, and φ is the mean porosity of the silicon metal-containing material.+

## Claims

### Claim 1

A method for producing technical silicon, comprising:
heating a particulate raw material mixture comprising particulate silicon metal-containing material and a particulate mediator which comprises at least one of the elements C, O, Al, Ca and Si,
to at least 1490° C., forming a liquid silicon metal phase, and
solidifying the liquid silicon metal phase,
wherein the particulate raw material mixture is characterized by a characteristic number K,
K having a value of 0.000 to 60 mm and being calculated as follows:
K
=
m
⁡
(
SiM
)
·
d
⁢
50
⁢
(
SiM
)
+
m
⁡
(
Med
)
·
d
⁢
50
⁢
(
Med
)
m
⁡
(
SiM
)
+
m
⁡
(
Med
)
·
φ
(
equation
⁢
1
)
where
m(SiM) is the mass of the silicon metal-containing material
m(Med) is the mass of the mediator in the raw material
mixture
d50,SiM is the particle size (diameter) in mm at 50% of the mass undersize of the grading curve of the silicon metal-containing material,
d50,Med is the particle size (diameter) in mm at 50% of the mass undersize of the grading curve of the mediator, and
φ is the mean porosity of the silicon metal-containing material,
where the silicon-containing material is not subjected to further purification steps.

### Claim 2 (depends on 1)

The method of claim 1, wherein the technical silicon produced has an Si content of at least 90% by mass.

### Claim 3 (depends on 1)

The method of claim 1, wherein the particles of the silicon metal-containing material have an average particle size d50,SiM of 0.1 to 100 mm.

### Claim 4 (depends on 1)

The method of claim 1, wherein the particles of the silicon metal-containing material have an average particle porosity of 0 to 0.6.

### Claim 5 (depends on 1)

The method of claim 1, wherein the particles of the mediator have a mean particle size d50,Med of 0.1 to 100 mm.

### Claim 6 (depends on 1)

The method of claim 1, wherein the mass ratio m of silicon metal-containing material/m of the mediator has a value of from 0.1 to 10.

### Claim 7 (depends on 1)

The method of claim 1, wherein the silicon metal-containing material comprises silicon residues which are byproducts or wastes of silicon-producing or silicon-processing industries.

### Claim 8 (depends on 1)

The method of claim 1, wherein the mean particle size of the silicon-containing material d50,SiM in the particulate raw material mixture is greater than the mean particle size of the mediator d50,Med.

### Claim 9 (depends on 1)

The method of claim 1, wherein the particulate mediator comprises the elements O, Si and Ca.

### Claim 10 (depends on 1)

The method of claim 1, wherein the particles of the mediator have a mean particle size of from 2 to 50 mm.

### Claim 11 (depends on 1)

The method of claim 1, wherein the particles of the mediator have a mean particle size of from 5 to 30 mm.

### Claim 12 (depends on 1)

The method of claim 1, wherein the silicon metal-containing material in the dry state contains at least 30 weight percent of metallic silicon.

### Claim 13 (depends on 1)

The method of claim 1, wherein the silicon metal-containing material in the dry state contains at least 40 weight percent of metallic silicon.

### Claim 14 (depends on 1)

The method of claim 1, wherein the particles of the silicon metal-containing material have a mean particle porosity of 0.05 to 0.4.

### Claim 15 (depends on 1)

The method of claim 1, wherein the particles of the silicon metal-containing material have a mean particle porosity of 0.1 to 0.35.

### Claim 16 (depends on 1)

The method of claim 1, wherein the particles of the silicon metal-containing material have a mean particle size of from 0.5-75 mm.

### Claim 17 (depends on 1)

The method of claim 1, wherein the particles of the silicon metal-containing material have a mean particle size of from 5-30 mm.