Calcium aluminate clinker as a refractory aggregate with and without barium addition and use thereof
View Patent ↗The present invention provides for a refractory aggregate composition comprising an improved calcium aluminate clinker having the formula C n A x wherein C is calcium oxide and A is aluminum oxide, wherein n is an integer from about 1 to about 12, wherein x is an integer from about 1 to about 24, and wherein said clinker has from zero to less than about fifty weight percent C 12 A 7 . Analogs, derivatives and hydrates of the improved calcium aluminate clinker are provided. A refractory composition and a sprayable refractory composition are disclosed comprising the improved calcium aluminate clinker. A method for improving the insulating character and/or penetration resistance of a liner in contact with molten aluminum in an aluminum manufacturing process or during aluminum transport is provided.
1. A method for improving the insulating character and/or penetration resistance of a liner in contact with molten aluminum in an aluminum manufacturing process or during aluminum transport, comprising:
lining an aluminum manufacturing and/or processing equipment with a refractory composition comprising a refractory aggregate consisting essentially of a calcium aluminate clinker having the formula C n A x , wherein C is equal to calcium oxide, wherein A is equal to aluminum oxide, wherein n is an integer from about 1 to about 12, wherein x is an integer from about 1 to about 24, and wherein said calcium aluminate clinker has from zero to less than about fifty weight percent C 12 A 7 , and wherein greater than 98 weight percent of said calcium aluminate clinker having a particle size ranging from 325 mesh to +10 mesh, for forming a liner prior to contacting said equipment with molten aluminum and for improving the insulating character and/or penetration resistance of said liner.
2. The method of claim 1 including wherein the refractory aggregate is porous.
3. The method of claim 1 including wherein the refractory aggregate is formed by sintering.
4. The method of claim 1 including wherein the refractory aggregate has little to no porosity.
5. The method of claim 1 including wherein the refractory aggregate is formed by a fusion process.
6. The method of claim 1 including treating said refractory composition with heat to a temperature not exceeding about 1820 degrees Centigrade.
7. The method of claim 1 including wherein the refractory composition includes analogs or derivatives of said C n A x , and optionally includes wherein barium is substituted for calcium in said calcium aluminate clinker.
8. The method of claim 1 including wherein the refractory composition comprises a source of barium, wherein said barium source is present in one or more phases as BaO, BA 6 , and C 2 BA 4 , and combinations thereof.
9. The method of claim 6 including wherein the refractory composition comprises a source of barium, wherein said barium source is present in one or more phases as BaO, BA 6 , and C 2 BA 4 , and combinations thereof.
10. The method of claim 1 including wherein the refractory composition comprises one or more of a reactive alumina, a calcined alumina, a tabular alumina, and a bubble alumina, and combinations thereof.
11. The method of claim 1 including wherein said refractory composition comprises one or more lightweight aggregates.
12. The method of claim 11 including wherein said lightweight aggregate is one or more of a bubble alumina, an expanded clay, a perlite, and a pyrophilite, and combinations thereof.
13. The method of claim 1 including wherein the refractory composition comprises at least one of a surfactant, and a fibrous material, and combinations thereof.
14. The method of claim 1 including wherein said refractory composition comprises a calcium aluminate cement.
15. The method of claim 1 including wherein said refractory composition comprises one or more of a set retarder, and a set accelerator, and combinations thereof.
16. The method of claim 14 including wherein said refractory composition comprises one or more of a reactive alumina, a surfactant, a fibrous material, a set retarder, and a set accelerator, and combinations thereof.
17. The method of claim 1 including adding an effective amount of water to achieve a pressable, castable, pumpable, or sprayable consistency of said refractory composition and for creating a hydrate phase of said C n A x .
18. The method of claim 17 including wherein said refractory composition comprises a calcium aluminate cement.
19. The method of claim 18 including wherein said sprayable refractory composition comprises a pumpable first component comprising said refractory composition and an effective amount of a dispersant, and said water, and optionally a second component comprising an effective amount of a flocculating agent, wherein said optional second component is added to said pumpable first component for achieving installation of the sprayable refractory composition.
20. The method of claim 19 including employing in combination with said dispersants one or more rheology affecting additives.
21. The method of claim 20 including wherein said rheology affecting additives are one or more of a boric acid retarder, a citric acid retarder, and a lithium carbonate, and combinations thereof.
22. The method of claim 17 including pressing said refractory composition into shape.
23. The method of claim 1 including pressing said refractory composition into shape.
24. The method of claim 1 including employing said refractory composition in a filtration process for molten aluminum.