Castable refractory composition
A castable refractory composition may include from 5% to 95% by weight of alumina, aluminosilicate, or mixtures thereof; up to 70% by weight silicon carbide; up to 10% by weight carbon; from 0.1% to 5% by weight alkaline earth metal oxide and/or hydroxide; and from 0.1% to 5% by weight of silica having a surface area of at least about 10 m 2 /g. The refractory composition may further include no more than 0.5% by weight of cementitious binder, and the refractory composition may not release a significant amount of hydrogen gas upon addition of water. The refractory composition may set on addition of water. An installable refractory lining may be formed using the composition and a method including at least one of casting, self-flowing, wet shotcreeting, rodding, cast-vibrating, spraying, conventional dry gunning, or high density gunning the castable refractory composition, and setting and drying the composition.
1. A castable refractory composition comprising:
from 5% to 95% by weight of alumina, aluminosilicate, or mixtures thereof;
silicon carbide in an amount up to 70% by weight;
carbon in an amount up to 10% by weight;
from 0.1% to 5% by weight alkaline earth metal oxide and/or hydroxide; and
from 0.1% to 5% by weight of silica having a surface area of at least about 10 m 2 /g,
wherein the refractory composition comprises no more than 0.5% by weight of cementitious binder,
wherein the refractory composition releases less than 25 cm 3 of hydrogen gas per kilogram of wetted castable refractory composition, and
wherein the refractory compositions sets on addition of water.
2. A castable refractory composition according to claim 1 , further comprising up to about 1% by weight of metallic additives.
3. A castable refractory composition according to claim 1 , further comprising up to about 5% by weight of an additive or combination of additives, which suppress or prevent the oxidation of carbon.
4. A castable refractory composition according to claim 1 , further comprising up to 0.5% by weight of organic fibers.
5. A castable refractory composition according to claim 1 , wherein the alumina, aluminosilicate or mixtures thereof comprise a material selected from the group consisting of brown fused alumina, sintered alumina, white fused alumina, calcined alumina, reactive or semi-reactive alumina, bauxite, fused or sintered mullite, andalusite and calcined chamotte with alumina content ranging from 30 to 75% by weight.
6. A castable refractory composition according to claim 1 , comprising from 5% to 70% by weight silicon carbide and/or from 1% to 10% by weight carbon.
7. A castable refractory composition according to claim 1 , wherein the silicon carbide comprises particles up to about 30 mm in size.
8. A castable refractory composition according to claim 1 , wherein the carbon comprises a material selected from carbon black, graphite, coke, solid hydrocarbon having a carbon residue of at least about 5% by weight after coking, or a combination thereof.
9. A castable refractory composition according to claim 1 , wherein the silica having a surface of at least about 10 m 2 /g is selected from the group consisting of fumed silica, silica fume, microsilica, micro grinded silica, and precipitated silica.
10. A castable refractory composition according to claim 1 , wherein the alkaline earth metal oxide and/or hydroxide is an oxide and/or hydroxide of magnesium, calcium, barium, or mixtures thereof.
11. A castable refractory composition according to claim 1 , wherein the composition comprise less than about 0.5% by weight calcium aluminate cement and/or calcium silicate cement.
12. An installable refractory lining obtained by mixing the castable refractory composition according to claim 1 with from 2% to 40% by weight water.
13. A method of installing the installable refractory lining of claim 12 , the method comprising at least one of casting, self-flowing, wet shotcreeting, rodding, cast-vibrating, spraying, conventional dry gunning, or high density gunning the castable refractory composition; and setting and drying the castable refractory composition to form the refractory lining.
14. The method of claim 13 , wherein the setting comprises reaction of the alkaline earth metal oxide and/or hydroxide, silica having a surface area of at least 10 m 2 /g, and water, without firing the castable refractory composition.
15. The method of claim 14 , wherein the mixture releases less than 10 cm 3 of hydrogen gas per kilogram of wet castable refractory.
16. An installed factory lining obtained by the method of claim 13 .
17. A method of installing a refractory comprising:
mixing the castable refractory composition according to claim 1 with water;
forming the mixture into an article;
allowing the article to set; and
drying the article to remove excess water.
18. The method of claim 17 , further comprising firing the article.
19. A refractory article obtained by the method of claim 17 .
20. The castable refractory compound of claim 1 , comprising silicon carbide in an amount between 15-40% by weight.