Graphite-containing refractory and method of producing graphite-containing refractory

Patent metadata

Field	Value
Publication number	US-11629916-B2
Application number	US-202117326424-A
Country	US
Kind code	B2
Filing date	May 21, 2021
Priority date	Feb 24, 2017
Publication date	Apr 18, 2023
Grant date	Apr 18, 2023

Abstract

A method of producing a graphite-containing refractory within which carbon fiber bundles are placed, the graphite constituting 1% to 80% by mass, the method including a bundling step of bundling carbon fibers to form the carbon fiber bundles; a mixing step of mixing a refractory raw material with graphite to prepare a graphite-containing refractory raw material; a pressing step of pressing the graphite-containing refractory raw material in which the carbon fiber bundles are placed to prepare a formed product; and a drying step of drying the pressed product, wherein the bundling step includes bundling 1000 to 300000 of the carbon fibers with a fiber diameter of 1 to 45 μm/fiber to form carbon fiber bundles 100 mm or more in length.

First claim

The invention claimed is:

1. A method of producing a graphite-containing refractory within which carbon fiber bundles are placed, the method comprising:
a bundling step of bundling carbon fibers to form the carbon fiber bundles;
a mixing step of mixing a refractory raw material with graphite to prepare a graphite-containing refractory raw material, the graphite constituting 1% to 80% by mass;
a pressing step of pressing the graphite-containing refractory raw material in which the carbon fiber bundles are placed to prepare a formed product; and
a drying step of drying the pressed product,
wherein the bundling step includes bundling 1000 to 300000 of the carbon fibers with a fiber diameter of 1 to 45 μm/fiber to form carbon fiber bundles 100 mm or more in length.

2. The method according to claim 1 , wherein the bundling step includes bundling 1000 to 60000 of the carbon fibers.

3. The method according to claim 1 , wherein
the refractory raw material is a magnesia raw material, and
the mixing step includes adding 20% to 99% by mass of the magnesia raw material.

4. The method according to claim 1 , wherein
the refractory raw material includes an alumina raw material and a silicon carbide raw material, and
the mixing step includes adding 10% to 95% by mass of the alumina raw material and adding the silicon carbide raw material at 1% or more by mass.

5. The method according to claim 4 , wherein
the refractory raw material includes an alumina raw material, a silicon carbide raw material, and a silica raw material,
the mixing step includes adding 10% to 95% by mass of the alumina raw material,
adding the silicon carbide raw material at 1% or more by mass, and
adding 1% to 50% by mass of the silica raw material.

6. The method according to claim 1 , wherein
the refractory raw material is a refractory waste, which is a crushed used refractory, and
the mixing step includes adding 10% to 90% by mass of the refractory waste.

7. The method according to claim 1 , wherein the bundling step includes bonding the carbon fibers with at least one adhesive selected from the group consisting of a phenolic resin, an epoxy resin, a melamine resin, a urea resin, an alkyd resin, an unsaturated polyester resin, polyurethane, thermosetting polyimide, an alumina sol, a silica sol, a zirconia sol, a chromia sol, a titania sol, a magnesia sol, a calcia sol, an yttria sol, pitch, tar, and a starch paste.

8. The method according to claim 1 , further comprising, before the pressing step:
a kneading step of kneading the graphite-containing refractory raw material; and
a filling step of filling a mold to press the graphite-containing refractory raw material with the kneaded graphite-containing refractory raw material and the carbon fiber bundle.

9. The method according to claim 8 , wherein the filling step includes filling 5% or more by volume of the mold with the graphite-containing refractory raw material, then placing the carbon fiber bundle at intervals of 3 mm or more, and repeatedly performing the filling and the placing to fill the mold with the graphite-containing refractory raw material and the carbon fiber bundle.

10. The method according to claim 1 , further comprising, before the pressing step:
a kneading step of kneading the graphite-containing refractory raw material; and
a filling step of filling a pressing vessel to press the graphite-containing refractory raw material with the kneaded graphite-containing refractory raw material and the carbon fiber bundle,
wherein the pressing step includes applying pressure to the pressing vessel via a pressure medium to prepare a pressed product.

11. The method according to claim 1 , wherein the mixing step includes adding short carbon fibers constituting 0.10% to 10% by mass based on 100% by mass of the graphite-containing refractory raw material, the short carbon fibers having a fiber diameter of 1 to 45 μm/fiber, a fiber length of 1 mm or less, and a ratio of fiber length to fiber diameter (fiber length/fiber diameter) of 2 to 1000.

12. A method of producing a graphite-containing refractory within which carbon fiber bundles are placed, the graphite constituting 1% to 80% by mass, the method comprising:
a bundling step of bundling carbon fibers to form the carbon fiber bundles;
a mixing step of mixing a refractory raw material with graphite to prepare a graphite-containing refractory raw material;
a pressing step of pressing the graphite-containing refractory raw material in which the carbon fiber bundles are placed to prepare a formed product; and
a drying step of drying the pressed product,
wherein the bundling step includes bundling 1000 to 300000 of the carbon fibers with a fiber diameter of 1 to 45 μm/fiber to form carbon fiber bundles 100 mm or more in length,
end faces of the carbon fiber bundles are a flat shape, and
the carbon fiber bundles are placed such that longitudinal directions of the end faces of the carbon fiber bundles are the same and that an angle between a pressing surface and the longitudinal direction of each end face is 45 degrees or more and 135 degrees or less.

13. The method according to claim 12 , wherein the bundling step includes bundling 1000 to 60000 of the carbon fibers.

14. The method according to claim 12 , wherein
the refractory raw material is a magnesia raw material, and
the mixing step includes adding 20% to 99% by mass of the magnesia raw material.

15. The method according to claim 12 , wherein
the refractory raw material includes an alumina raw material and a silicon carbide raw material, and
the mixing step includes adding 10% to 95% by mass of the alumina raw material and adding the silicon carbide raw material at 1% or more by mass.

16. The method according to claim 15 , wherein
the refractory raw material includes an alumina raw material, a silicon carbide raw material, and a silica raw material,
the mixing step includes adding 10% to 95% by mass of the alumina raw material,
adding the silicon carbide raw material at 1% or more by mass, and
adding 1% to 50% by mass of the silica raw material.

17. The method according to claim 12 , wherein
the refractory raw material is a refractory waste, which is a crushed used refractory, and
the mixing step includes adding 10% to 90% by mass of the refractory waste.

18. The method according to claim 12 , wherein the bundling step includes bonding the carbon fibers with at least one adhesive selected from the group consisting of a phenolic resin, an epoxy resin, a melamine resin, a urea resin, an alkyd resin, an unsaturated polyester resin, polyurethane, thermosetting polyimide, an alumina sol, a silica sol, a zirconia sol, a chromia sol, a titania sol, a magnesia sol, a calcia sol, an yttria sol, pitch, tar, and a starch paste.

19. The method according to claim 12 , further comprising, before the pressing step:
a kneading step of kneading the graphite-containing refractory raw material; and
a filling step of filling a mold to press the graphite-containing refractory raw material with the kneaded graphite-containing refractory raw material and the carbon fiber bundle.

20. The method according to claim 19 , wherein the filling step includes filling 5% or more by volume of the mold with the graphite-containing refractory raw material, then placing the carbon fiber bundle at intervals of 3 mm or more, and repeatedly performing the filling and the placing to fill the mold with the graphite-containing refractory raw material and the carbon fiber bundle.

Assignees

• Jfe Steel Corp

Inventors

• Yoshida Keisuke
• Matsunaga Hisahiro
• Hama Yoichiro

Classifications

• C04B2235/3241

  Chromium oxides, chromates, or oxide-forming salts thereof · CPC title

• C04B2235/3826

  Silicon carbides · CPC title

• C04B2235/526

  characterised by the length of the fibers · CPC title

• C04B2235/48

  Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins · CPC title

• C04B2235/3232

  Titanium oxides or titanates, e.g. rutile or anatase · CPC title