# US 4,395,285 A · Low density compacts of prepared mix for use in the production of silicon and ferrosilicon

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- Number: US 4,395,285 A
- Document ID: US4395285A
- Status: Granted
- Kind: A
- Application number: 06/304,652
- Filed: 1981-09-23
- Granted: 1983-07-26
- Earliest claimed: 1980-03-26
- Assignees: Elkem Metals Company
- Inventors: Rodney F. Merkert
- Web page: https://patentgrep.com/patent/US4395285A

## CPC

- C01B 33/025: with carbon or a solid carbonaceous material, i.e. carbo-thermal process
- C22B 1/245: with carbonaceous material for the production of coked agglomerates
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS

## Abstract

A low density, porous compact of prepared mix containing silica fume, finely-divided carbonaceous reducing agent such as petroleum coke or coal, optionally iron and a binder.

## Claims

### Claim 1

Pieces of a low density, porous compact for use as the feed to an electric furnace in the production of silicon and ferrosilicon comprising finely-divided silica-containing material including at least about 25 parts by weight of silica fume per 100 parts by weight of total silica, and a finely-divided carbonaceous reducing agent in an amount such that the total carbon ranges from about 35 to 50 parts by weight carbon per 100 parts by weight of total silica; the compact having an apparent density of between about 0.8 and 1.2 grams per cubic centimeter, a bulk density of between about 25 and 40 pounds per cubic foot and an internal porosity of between about 50 and 60% voids.

### Claim 2 (depends on 1)

A low density, porous compact according to claim 1 wherein the silica-containing material includes at least about 25 parts by weight of silica sand per 100 parts by weight of total silica.

### Claim 3 (depends on 1)

A low density, porous compact according to claim 1 wherein the silica-containing material includes at least about 25 parts by weight of Sidley gravel per 100 parts by weight of total silica.

### Claim 4 (depends on 1)

A low density, porous compact according to claim 1 wherein the carbonaceous reducing agent includes about 30 parts by weight of petroleum coke per 100 parts by weight of total silica.

### Claim 5 (depends on 1)

A low density, porous compact according to claim 1 wherein the carbonaceous reducing agent includes about 17 parts by weight of coal per 100 parts by weight of total silica.

### Claim 6 (depends on 1)

A low density, porous compact according to claim 1 further including up to about 15 parts by weight of iron particles per 100 parts by weight of total silica.

### Claim 7 (depends on 1)

A low density, porous compact according to claim 1 further including up to about 2.5 parts by weight of a cereal binder per 100 parts by weight of total silica.

### Claim 8

Pieces of a low density, porous compact for use as the feed to an electric furnace in the production of silicon and ferrosilicon comprising a finely-divided silica-containing material including from about 25 to 50 parts by weight each of silica fume, silica sand and Sidley gravel, about 30 parts by weight of petroleum coke, about 17 parts by weight of coal, from 0 to about 15 parts by weight of iron particles and about 2.5 parts by weight of a cereal binder, all based on 100 parts by weight of total silica; the compact having an apparent density of between about 1 and 1.2 grams of per cubic centimeter, a bulk density of between about 30 and 35 pounds per cubic foot, and an internal porosity of about 56% voids.