# US 11,299,432 B2 · Method of making a refractory article

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- Number: US 11,299,432 B2
- Document ID: US11299432B2
- Status: Granted
- Kind: B2
- Application number: 16/725,122
- Filed: 2019-12-23
- Published: 2021-02-18
- Granted: 2022-04-12
- Earliest claimed: 2019-08-14
- Assignees: Pyrotek High Temperature Industrial Products Inc.
- Applicants: Pyrotek High Temperature Industrial Products Inc.
- Inventors: Marcel Gouin; François Veillette; Alain Simard
- Web page: https://patentgrep.com/patent/US11299432B2

## CPC

- C04B 35/565: based on silicon carbide
- B28B 1/007: {by freezing the material}
- B28B 11/243: {Setting, e.g. drying, dehydrating or firing ceramic articles (B28B11/242 takes precedence)}
- C04B 35/013: {containing carbon (C04B35/103 takes precedence)}
- C04B 35/14: based on silica
- C04B 35/22: rich in calcium oxide {, e.g. wollastonite (C04B35/195 takes precedence)}
- C04B 35/62635: {Mixing details}
- C04B 35/62665: {Flame, plasma or melting treatment}
- C04B 35/62685: {characterised by the order of addition of constituents or additives}
- C04B 35/6303: {Inorganic additives}
- C04B 35/6316: {Binders based on silicon compounds}
- C04B 35/632: Organic additives
- C04B 35/636: Polysaccharides or derivatives thereof
- C04B 35/64: Burning or sintering processes (C04B33/32 takes precedence {; powder metallurgy B22F})
- C04B 35/66: Monolithic refractories or refractory mortars, including those whether or not containing clay {(making or repairing of linings F27D1/16)}
- C04B 38/067: {Macromolecular compounds (C04B38/062 takes precedence)}
- C04B 2111/00431: {Refractory materials}
- C04B 2111/40: Porous or lightweight materials
- C04B 2235/3206: Magnesium oxides or oxide-forming salts thereof
- C04B 2235/3208: Calcium oxide or oxide-forming salts thereof, e.g. lime
- C04B 2235/3212: Calcium phosphates, e.g. hydroxyapatite
- C04B 2235/3217: Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
- C04B 2235/3225: Yttrium oxide or oxide-forming salts thereof
- C04B 2235/3244: Zirconium oxides, zirconates, hafnium oxides, hafnates, or oxide-forming salts thereof
- C04B 2235/3418: Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
- C04B 2235/3454: Calcium silicates, e.g. wollastonite
- C04B 2235/3826: Silicon carbides
- C04B 2235/448: Sulphates or sulphites
- C04B 2235/602: Making the green bodies or pre-forms by moulding
- C04B 2235/6027: Slip casting
- C04B 2235/656: characterised by specific heating conditions during heat treatment
- C04B 2235/77: Density
- C04B 2235/96: Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
- C04B 2235/9615: Linear firing shrinkage
- C04B 2235/9669: Resistance against chemicals, e.g. against molten glass or molten salts
- 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
- B28B: SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER (foundry moulding B22C; working stone or stone-like material B28D; shaping of substances in a plastic state, in general B29C; making layered products not composed wholly of these substances B32B)

## Abstract

A method of making a refractory article is provided. The method includes: a) mixing a binder system, a refractory charge, and a second colloidal binder to form an aqueous slurry; b) casting the aqueous slurry into a mold; c) subjecting the mold containing the aqueous slurry to a temperature that is lower than a slurry casting temperature for a time sufficient to form a green strength article; and d) firing the green strength article at a temperature of at least 450° C. for a time sufficient to achieve thermal homogeneity, thereby forming a refractory article. Refractory articles made in accordance with the method have a unique combination of pore structure and mechanical properties.

## Claims

### Claim 1

A method of making a refractory article, the method comprising:
a) mixing a binder system, a refractory charge, and a second colloidal binder to form an aqueous slurry;
b) casting the aqueous slurry into a mold, wherein the aqueous slurry is at a slurry casting temperature;
c) subjecting the mold containing the aqueous slurry to a temperature that is less than the slurry casting temperature for a time sufficient to form a green strength article; and
d) firing the green strength article at a temperature of at least 450° C. for a time sufficient to achieve thermal homogeneity, thereby forming a refractory article,
wherein the binder system comprises from 2 wt % to 10 wt % of the aqueous slurry, the refractory charge comprises from 40 wt % to 75 wt % of the aqueous slurry, and the second colloidal binder comprises from 20 wt % to 50 wt % of the aqueous slurry.

### Claim 2 (depends on 1)

The method of claim 1, further comprising placing a reinforcement material into or on the mold.

### Claim 3 (depends on 1)

The method of claim 1, wherein the mold containing the aqueous slurry is subjected to a temperature of −195° C. to 0° C.

### Claim 4 (depends on 1)

The method of claim 1, wherein the mold containing the aqueous slurry is subjected to a temperature of −100° C. to −30° C.

### Claim 5 (depends on 1)

The method of claim 1, further comprising demolding the green strength article.

### Claim 6 (depends on 1)

The method of claim 1, wherein the green strength article is not subjected to a drying step prior to the firing step.

### Claim 7 (depends on 1)

The method of claim 1, further comprising forming the binder system, wherein forming the binder system comprises:
preparing a mixture comprising water and a carbohydrate;
heating the mixture to a caramelization temperature for an effective amount of time to caramelize the carbohydrate and form a caramelized carbohydrate component; and
mixing the caramelized carbohydrate component with a first colloidal binder and an adjuvant to form the binder system.

### Claim 8 (depends on 1)

The method of claim 1, wherein the binder system comprises a caramelized carbohydrate component, a first colloidal binder, and an adjuvant.

### Claim 9 (depends on 8)

The method of claim 8, wherein the caramelized carbohydrate component is derived from at least one of sucrose, glucose, fructose, galactose, maltose, or lactose.

### Claim 10 (depends on 8)

The method of claim 8, wherein the first colloidal binder comprises at least one of a colloidal silica, a colloidal alumina, a colloidal zirconia, a colloidal yttria, an organically modified colloidal silica, an organically modified colloidal alumina, an organically modified colloidal zirconia, or an organically modified colloidal yttria.

### Claim 11 (depends on 8)

The method of claim 8, wherein the adjuvant comprises at least one of an acid, an inorganic wetting agent, or an acid phosphate adhesive.

### Claim 12 (depends on 11)

The method of claim 11, wherein when the adjuvant comprises an acid, the acid comprises at least one of phosphoric acid, sulfuric acid, citric acid, acetic acid, boric acid, or oxalic acid;
wherein when the adjuvant comprises an inorganic wetting agent, the inorganic wetting agent comprises at least one of aluminum ammonium sulfate, magnesium sulfate, aluminum sulfate, or calcium sulfate; and
wherein when the adjuvant comprises an acid phosphate adhesive, the acid phosphate adhesive comprises at least one of calcium phosphate, magnesium phosphate, or aluminum phosphate.

### Claim 13 (depends on 8)

The method of claim 8, wherein the caramelized carbohydrate component comprises from 5 wt % to 70 wt % of the binder system, the adjuvant comprises from 0.25 wt % to 10 wt % of the binder system, and the first colloidal binder comprises from 25 wt % to 90 wt % of the binder system.

### Claim 14 (depends on 1)

The method of claim 1, wherein the refractory charge comprises at least one of a silicate, a metal oxide, a boride, a nitride, a carbide, a sulfide, a fluoride, an aluminide, a synthetic glass, glass fibers, refractory ceramic fibers, non-refractory ceramic fibers, graphite, bone ash, aluminum titanate, or calcium aluminate.

### Claim 15 (depends on 1)

The method of claim 1, wherein the second colloidal binder comprises at least one of a colloidal silica, a colloidal alumina, a colloidal zirconia, a colloidal yttria, an organically modified colloidal silica, an organically modified colloidal alumina, an organically modified colloidal zirconia, or an organically modified colloidal yttria.

### Claim 16 (depends on 1)

The method of claim 1, further comprising cooling the refractory article after the firing step.