# US 5,344,802 A · MgO-spinel refractory mix and shapes made therefrom

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- Number: US 5,344,802 A
- Document ID: US5344802A
- Status: Granted
- Kind: A
- Application number: 08/152,900
- Filed: 1993-11-15
- Granted: 1994-09-06
- Earliest claimed: 1993-11-15
- Assignees: Indresco Inc.
- Inventors: Richard J. Knauss
- Web page: https://patentgrep.com/patent/US5344802A

## CPC

- C04B 35/443: Magnesium aluminate spinel
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE

## Abstract

A refractory mix and resultant shapes formed by burning the mix, the mix comprising a magnesia-alumina spinel grain containing at least 27% MgO by weight, a fused magnesite grain, and up to 10% by weight alumina, it being possible to substitute a sintered magnesite grain for up to 50% by weight of the fused magnesite grain.

## Claims

### Claim 1

A refractory mix for forming shaped refractories consisting essentially of 10 to 40% by weight of a magnesia-alumina spinel grain containing at least 28% MgO by weight, 60 to 90% by weight of a fused magnesite grain and up to 10% by weight alumina.

### Claim 2 (depends on 1)

The mix of claim 1 including a binder and in which a sintered magnesite grain is substituted for up to about 50% by weight of the fused magnesite grain.

### Claim 3 (depends on 1)

The mix of claim 1, wherein the mix consists essentially of 10 to 40% by weight of magnesia-alumina spinel grain containing at least 28% MgO by weight, 0% by weight alumina and, correspondingly, 60% to 90% by weight of a fused magnesite grain.

### Claim 4 (depends on 3)

The mix of claim 3, including a binder and in which a sintered magnesite grain is substituted for up to about 50% by weight of the fused magnesite grain.

### Claim 5

A refractory shape formed by burning a mix consisting essentially of 10 to 40% by weight of a magnesia-alumina spinel grain containing at least 28% MgO by weight, 60 to 90% by weight of a fused magnesite grain and up to 10% by weight alumina.

### Claim 6 (depends on 5)

The shape of claim 5 in the form of a brick and wherein a binder is included in the mix.

### Claim 7 (depends on 6)

The brick of claim 6 wherein the mix consists essentially of 10 to 40% by weight of a magnesia-alumina spinel grain containing at least 28% MgO by weight, 0% by weight alumina and, correspondingly, 60 to 90% by weight of a fused magnesite grain.

### Claim 8 (depends on 7)

The brick of claim 7 including a binder and in which a sintered magnesite grain is substituted for up to about 50% by weight of the fused magnesite grain.