Method for manufacturing a refractory for an inner lining of a blast furnace and blast furnace having the inner lining
A refractory, which is particularly suitable for use in an inner lining of a blast furnace, is obtainable by a process. The process includes providing a mixture containing coke, silicon and a binder. A green block is formed from the mixture. The green block is then baked. The baked block is semi-graphitized at a temperature between 1600 and 2000° C.
1. A method of manufacturing a refractory, which comprises the steps of:
providing a mixture containing coke having an iron content of at most 0.1% by weight, silicon and a binder;
forming a green block from the mixture;
baking the green block at a temperature between 700 and 1200° C. and resulting in a baked block; and
semi-graphitizing the baked block at a temperature between 1600 and 2000° C.
2. The method according to claim 1 , which further comprises providing the coke to contain at least 50% by weight of isotropic coke.
3. The method according to claim 1 , which further comprises adding graphite to the mixture.
4. The method according to claim 3 , which further comprises providing a synthetic graphite as the graphite.
5. The method according to claim 3 , which further comprises providing the mixture to contain 60 to 85% by weight of a mixture of the coke and of the graphite based on a dry aggregate of the refractory.
6. The method according to claim 1 , which further comprises providing the mixture to contain 5 to 15% by weight of the silicon based on a dry aggregate of the refractory.
7. The method according to claim 1 , which further comprises providing the mixture to contain 6 to 14% by weight of titanium dioxide based on a dry aggregate of the refractory.
8. The method according to claim 1 , which further comprises providing the mixture to contain 4 to 15% by weight of a silicon carbide-carbon powder mix based on a dry aggregate of the refractory, which contains at least 50% by weight of silicon carbide.
9. The method according to claim 1 , which further comprises selecting the binder from the group consisting of coal-tar pitch, petroleum pitch, phenolic resin, furfurylic resin, coal tar, petroleum tar and any mixture of at least two of the aforementioned compounds.
10. The method according to claim 1 , which further comprises providing the mixture to contain:
65 to 75% by weight of the coke having the iron content of at most 0.1% by weight and of graphite;
9 to 11% by weight of the silicon;
9 to 11% by weight of titanium dioxide;
8 to 11% by weight of silicon carbide-carbon powder, wherein a sum of the aforementioned ingredients is 100% by weight except for the binder; and
the binder.
11. The method according to claim 1 , which further comprises performing the forming step by one of block pressing, extrusion, hot pressing or vibro-molding.
12. The method according to claim 1 , which further comprises semi-graphitizing the baked block at a temperature between 1700 and 2000° C.
13. The method according to claim 1 , which further comprises:
impregnating the baked block one of before or after the semi-graphitization step with an impregnation agent selected from the group consisting of coal tar, petroleum tar, coal-tar pitch, petroleum pitch, resin and mixtures of at least two of the aforementioned compounds resulting in an impregnated green block; and
rebaking the impregnated green block at a temperature between 700 and 1200° C.
14. The method according to claim 1 , which further comprises performing the baking step and the semi-graphitizing step concurrently.
15. The method according to claim 1 , which further comprises providing the coke to contain at least 99% of isotropic coke.
16. The method according to claim 1 , wherein the coke has an iron content of at most 0.001% by weight.
17. The method according to claim 1 , which further comprises providing the mixture to contain:
60 to 80% by weight of the coke having an iron content of at most 0.1% by weight and of graphite;
7 to 12% by weight of the silicon;
8 to 13% by weight of titanium dioxide;
6 to 13% by weight of silicon carbide-carbon powder, wherein a sum of the aforementioned ingredients is 100% by weight except for the binder; and
the binder.
18. A blast furnace, comprising:
an inner lining containing at least one refractory formed by the process steps of:
providing a mixture containing coke having an iron content of at most 0.1% by weight, silicon and a binder;
forming a green block from the mixture;
baking the green block at a temperature between 700 and 1200° C. and resulting in a baked block; and
semi-graphitizing the baked block at a temperature between 1600 and 2000° C.
19. A method of making an inner lining for a blast furnace, which comprises the steps of:
forming a refractory by the steps of:
providing a mixture containing coke having an iron content of at most 0.1% by weight, silicon and a binder;
forming a green block from the mixture;
baking the green block at a temperature between 700 and 1200° C. and resulting in a baked block;
semi-graphitizing the baked block at a temperature between 1600 and 2000° C. resulting in the refractory; and
forming the refractory into a shape of the inner lining for the blast furnace.