Calcium enriched refractory material by the addition of calcium carbonate
View Patent ↗The composition applied to the refractory structure has a magnesia-based refractory material, calcium carbonate and a binder. After application of the refractory material to a refractory structure and upon application of heat to the applied refractory material a matrix is formed which protects against penetration of the slag into the refractory material. The resulting refractory material has improved hot strength, slag resistance and durability.
1. A composition suitable for providing a refractory material comprising:
20 to 95 weight percent magnesia containing refractory material;
0.1 to 5.0 weight percent of a binder; and
2.0 to 10 weight percent of calcium carbonate for reacting upon exposure to heat to provide the refractory material as a source of calcium oxide for increasing corrosion resistance.
2. The composition according to claim 1 wherein the binder is an organic acid.
3. The composition according to claim 1 wherein the magnesia containing refractory material is present in an amount of 60 to 88 weight percent.
4. The composition according to claim 1 further comprising calcium hydroxide in amount of 0.2 to 8.0 weight percent.
5. The composition according to claim 1 further comprising a plasticizer in an amount of 0.1 to 2.0 weight percent.
6. The composition according to claim 5 wherein the plasticizer is bentonite.
7. The composition according to claim 1 further comprising a dispersant in an amount of from 0.1 to 1.0 weight percent.
8. The composition according to claim 7 wherein the dispersant is citric acid.
9. The composition according to claim 1 wherein the binder is sulfamic acid wherein the sulfamic acid is present in an amount of 0.2 to 3.0 weight percent.
10. The composition according to claim 1 wherein the calcium carbonate is present in an amount of 2.0 to 7.0 weight percent wherein the calcium carbonate has a particle size of less than 325 mesh.
11. The composition according to claim 1 wherein the calcium carbonate is present in a very fine portion having a particle size of less than 325 mesh and a coarser portion wherein the coarser portion has a particle size less than 20 mesh, 15 weight percent larger than 40 mesh, 75 weight percent larger than 100 mesh and 92 weight percent larger than 200 mesh.
12. The composition according to claim 11 wherein the very fine portion is present in an amount of 2.5 to 3.5 weight percent and the coarser portion is present in an amount of 2.5 to 3.5 weight percent.
13. The composition according to claim 11 wherein the very fine portion is present in an amount of 3.5 to 4.5 weight percent and the coarser portion is present in an amount of 3.5 to 4.5 weight percent.
14. The composition according to claim 12 further comprising 0.2 to 3.0 weight percent sulfamic acid.