Backup thermal insulation plate

• US 7,413,797 B2
• Filed: 05/31/2007
• Issued: 08/19/2008
• Est. Priority Date: 05/31/2006
• Status: Active Grant

• Current Assignee: Unifrax I LLC (ASP Unifrax Holdings, Inc.)
• Original Assignee: Unifrax ILLC
• Inventors: de Souza, Mauricio Munhoz
• Primary Examiner(s): EDWARDS, NEWTON O
• Application Number:
  US11/809,352
• Publication Number:
  US 20070281565A1
• Time in Patent Office: 446 Days
• Field of Search: 428/292.1, 428/293.4, 428/292.4, 442/179, 442/172, 442/136, 501/95.2
• US Class Current: 428/293.4
• CPC Class Codes: C04B 14/062 Microsilica, e.g. colloïdal silica preparing microsilica slurries or suspensions C04B18/148
• CPC Class Codes: C04B 14/303 Alumina
• CPC Class Codes: C04B 14/4625 Alumina
• CPC Class Codes: C04B 14/4656 Al-silicates, e.g. clay
• CPC Class Codes: C04B 2103/445 Gelling agents
• CPC Class Codes: C04B 2111/28 Fire resistance, i.e. materials resistant to accidental fires or high temperatures
• CPC Class Codes: C04B 22/066 Magnesia; Magnesium hydroxide
• CPC Class Codes: C04B 22/122 Acids
• CPC Class Codes: C04B 22/124 Chlorides of ammonium or of the alkali or alkaline earth metals, e.g. calcium chloride
• CPC Class Codes: C04B 22/165 Acids
• CPC Class Codes: C04B 2201/20 for the density
• CPC Class Codes: C04B 2201/50 for the mechanical strength
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3229 Cerium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3232 Titanium oxides or titanates, e.g. rutile or anatase
• CPC Class Codes: C04B 2235/3244 Zirconium oxides, zirconates, hafnium oxides, hafnates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/44 Metal salt constituents or additives chosen for the nature of the anions, e.g. hydrides or acetylacetonate
• CPC Class Codes: C04B 2235/444 Halide containing anions, e.g. bromide, iodate, chlorite
• CPC Class Codes: C04B 2235/449 : Organic acids, e.g. EDTA, citrate, acetate, oxalate
• CPC Class Codes: C04B 2235/48 : Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins
• CPC Class Codes: C04B 2235/5208 : Fibers
• CPC Class Codes: C04B 2235/5224 : Alumina or aluminates
• CPC Class Codes: C04B 2235/5232 : Silica or silicates other than aluminosilicates, e.g. quartz
• CPC Class Codes: C04B 2235/5236 : Zirconia
• CPC Class Codes: C04B 2235/5252 : having a specific pre-form
• CPC Class Codes: C04B 2235/5454 : nanometer sized, i.e. below 100 nm
• CPC Class Codes: C04B 2235/604 : Pressing at temperatures other than sintering temperatures
• CPC Class Codes: C04B 2235/606 : Drying
• CPC Class Codes: C04B 2235/616 : Liquid infiltration of green bodies or pre-forms
• CPC Class Codes: C04B 2235/77 : Density
• CPC Class Codes: C04B 2235/96 : Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
• CPC Class Codes: C04B 2235/9607 : Thermal properties, e.g. thermal expansion coefficient
• CPC Class Codes: C04B 24/04 : Carboxylic acids; Salts, anhydrides or esters thereof
• CPC Class Codes: C04B 24/38 : Polysaccharides or derivatives thereof C04B24/243 takes precedence
• CPC Class Codes: C04B 24/383 : Cellulose or derivatives thereof
• CPC Class Codes: C04B 30/02 : containing fibrous materials
• CPC Class Codes: C04B 35/14 : based on silica
• CPC Class Codes: C04B 35/624 : Sol-gel processing
• CPC Class Codes: C04B 35/6263 : characterised by their solids loadings, i.e. the percentage of solids
• CPC Class Codes: C04B 35/62655 : Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying
• CPC Class Codes: C04B 35/80 : Fibres, filaments, whiskers, platelets, or the like
• CPC Class Codes: C04B 41/009 : characterised by the material treated
• CPC Class Codes: C04B 41/5007 : with salts or salty compositions, e.g. for salt glazing C04B41/5006 takes precedence
• CPC Class Codes: C04B 41/5016 : Acids
• CPC Class Codes: C04B 41/5089 : Silica sols, alkyl, ammonium or alkali metal silicate cements
• CPC Class Codes: C21B 7/06 : Linings for furnaces
• CPC Class Codes: C21B 7/14 : Discharging devices, e.g. for slag
• CPC Class Codes: F16L 59/026 : Mattresses, mats, blankets or the like
• CPC Class Codes: Y10T 428/249928 : Fiber embedded in a ceramic, glass, or carbon matrix
• CPC Class Codes: Y10T 442/2631 : Coating or impregnation provides heat or fire protection
• CPC Class Codes: Y10T 442/2926 : Coated or impregnated inorganic fiber fabric
• CPC Class Codes: Y10T 442/2975 : Coated or impregnated ceramic fiber fabric

Abstract

A backup thermal insulation plate includes a colloidal inorganic oxide-impregnated, pressed and dried high-temperature-resistant inorganic-fiber blanket or board, the plate having a use temperature up to at least about 1000° C. and maintaining mechanical integrity after exposure to the use temperature, the plate having a density greater than or equal to about 500 kg/m³, and a compression resistance of at least about 50 kgf/cm².

Claims

1. A thermal insulation article comprising a colloidal inorganic oxide-impregnated, pressed and dried high-temperature-resistant inorganic-fiber blanket or board, wherein the colloidal inorganic oxide is a composition of the colloidal inorganic oxide in combination with a gelling agent;

the article having a use temperature up to at least about 1000°

C. and maintaining mechanical integrity after exposure to the use temperature, the article having a density greater than or equal to about 500 kg/m³, and a compression resistance of at least about 50 kgf/cm².

2. The thermal insulation article of claim 1, wherein the colloidal inorganic oxide is a composition of colloidal silica in combination with a gelling agent;

the article having a density greater than or equal to about 700 kg/m³, and a compression resistance of at least about 80 kgf/cm².

3. The thermal insulation article of claim 2, wherein the colloidal inorganic oxide composition comprises about 30 to 100% by weight colloidal silica, the gelling agent at about 0.01 to about 10% by weight of an inorganic salt or oxide and about 0.01 to about 10% by weight of an acid, and water in an amount sufficient to solubilize the gelling agent, optionally in an amount up to about 70% by weight of the composition.

4. The thermal insulation article of claim 3, wherein the article has a density greater than or equal to about 900 kg/m³, a compression resistance of at least about 120 kgf/cm², and a thermal conductivity of less than or equal to about 0.45 W/mK at a temperature ranging from about 700 to about 800°

C.

5. The thermal insulation article of claim 3, comprising about 30 to about 80 percent by weight fiber, and about 20 to about 70 percent by weight colloidal silica.

6. The thermal insulation article of claim 3, wherein the gelling agent inorganic salt or oxide comprises at least one of ammonium acetate, calcium chloride, magnesium chloride, or magnesium oxide, and the acid comprises at least one of acetic acid, hydrochloric acid, or phosphoric acid.

7. The thermal insulation article of claim 2, wherein the high-temperature-resistant inorganic-fiber blanket or board is re-impregnated with at least colloidal silica after a first impregnation with the colloidal inorganic oxide composition, pressing and optionally drying;

the article having a density greater than or equal to about 1100 kg/m³, and a compression resistance of at least about 300 kgf/cm².

8. The thermal insulation article of claim 7, comprising about 20 to about 60 percent by weight fiber, and about 40 to about 80 percent by weight colloidal silica.

9. The thermal insulation article of claim 1, comprising a colloidal-silica-impregnated vacuum cast ceramic-fiber board, the article having a use temperature up to about 1300°

C., a density greater than or equal to about 700 kg/m³, and a compression resistance of at least about 70 kgf/cm².

10. The thermal insulation article of claim 9, wherein the vacuum cast ceramic fiber board, prior to colloidal silica impregnation, comprises about 0.4 to about 50 percent by weight high alumina fiber, about 4 to about 90 percent by weight tabular alumina, and about 0.01 to about 0.2 percent by weight starch.

11. The thermal insulation article of claim 9, comprising about 40 to about 80 percent by weight fiber, and about 20 to about 60 percent by weight colloidal silica.

12. The thermal insulation article of claim 9, wherein the vacuum cast ceramic fiber board is cast from an aqueous slurry comprising about 0.1 to about 2% by weight aluminosilicate fiber, about 0.01 to about 1.25% by weight high alumina fiber and about 0.1 to about 1.9% by weight of an inorganic densifying agent, said densifying agent optionally being tabular alumina, and said slurry further optionally comprising starch and colloidal silica.

13. The thermal insulation article of claim 9, having a thermal conductivity of less than or equal to about 0.2 W/mK at a temperature ranging from about 700 to about 800°

C.

14. The thermal insulation article of claim 2, wherein the high-temperature-resistant inorganic-fiber comprises at least one of refractory ceramic fiber (RCF), aluminosilicate fiber, high alumina fiber, alkaline earth silicate fiber, alumino silica zirconia fiber, or mixtures thereof.

15. The thermal insulation article of claim 1, wherein the compression resistance is substantially uniform throughout the article.

16. The thermal insulation article of claim 1 wherein the colloidal inorganic oxide comprises at least one of colloidal silica, colloidal alumina, colloidal zirconia, colloidal titania, colloidal ceria, or colloidal yttria.

17. The thermal insulation article of claim 2, wherein the thermal insulation article comprises a colloidal silica-impregnated high temperature resistant inorganic fiber blanket that optionally prior to pressing, is contacted together with a colloidal silica-impregnated vacuum cast ceramic fiber board, pressed and dried, to produce a composite thermal insulation article.

18. The thermal insulation article of claim 1, wherein the thermal insulation article comprises backup thermal insulation for at least one of a ladle, torpedo car, trough runner, or tundish.