Ceramic bottom lining of a blast furnace hearth

Patent metadata

Field	Value
Publication number	US-9835331-B2
Application number	US-201113994833-A
Country	US
Kind code	B2
Filing date	Dec 16, 2011
Priority date	Dec 17, 2010
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A hearth for a metallurgical furnace, in particular for a blast furnace, the hearth including a wall lining and a bottom lining of refractory material for containing a molten metal bath, the bottom lining including a lower region and an upper region that is arranged to cover the top of the lower region and that is built of ceramic elements, the ceramic elements of the upper region being made of microporous ceramic material including a granular phase made of a silico-aluminous high alumina content granular material and a binding phase for binding grains of said granular material, said microporous ceramic material having thus an maintaining permanently a thermal conductivity lower than 7 W/m.° K.

First claim

The invention claimed is:

1. A hearth for a metallurgical furnace comprising:
a wall lining and a bottom lining that are made of refractory material for containing a bath comprising molten metal;
said bottom lining having a lower region comprising a carbon refractory layer and an upper region that comprises a layer of ceramic elements arranged to cover said lower region
wherein said ceramic elements of said upper region are made of microporous ceramic material comprising a granular phase made of a silico-aluminous high alumina content granular material and a binding phase for binding grains of said granular material, said microporous ceramic material having a thermal conductivity lower than 7 W/m.° K; a permeability ≦2 nanoperms and a mean pore width ≦2 μm,
wherein said wall lining delimits a substantially horizontal top surface of said lower region and said layer of ceramic elements is an assembly that comprises bricks or blocks and that completely covers said top surface, wherein the ceramic elements are large-size blocks, measuring more than 200×400×500 mm, having a first part made of ceramic material baked in nitrogen atmosphere, said first part having an upper side and a lower side and comprising at least one conical blind hole disposed in the blocks, the at least one blind hole being open into said lower side, and a second part made of a refractory material rammed in said blind holes, the blind holes being arranged so that any point located in the ceramic material of the first part is at a distance from a surface of said first part lower than a maximum penetration depth of impermeation achievable by a baking process used for producing said blocks.

2. The hearth as claimed in claim 1 , wherein said microporous ceramic material has a permeability ≦1 nanoperm.

3. The hearth as claimed in claim 1 , wherein said microporous ceramic material has a mean pore width ≦1 μm.

4. The hearth as claimed in claim 1 , wherein the granular phase comprises one or more of the followings: andalusite, chamotte, corundum, synthetic mullite.

5. The hearth as claimed in claim 4 , wherein the granular phase comprises granular andalusite with an Al 2 O 3 content of 55-65 wt %.

6. The hearth as claimed in claim 1 , wherein the binding phase comprise a nitrided bond.

7. The hearth as claimed in claim 6 , wherein the binding phase is based on silicon, aluminum, oxygen and nitrogen, in a range of ratii configured to generate a SiAlON bond.

8. The hearth as claimed in claim 1 , wherein the ceramic elements are large-size ceramic blocks, measuring more than 200×400×500 mm, disposed in a herringbone pattern.

9. The hearth as claimed in claim 8 , wherein the wall lining comprise, at the same level as said upper region, refractory blocks matching with said large-size ceramic blocks in said herringbone pattern, each alignment or group of alignments of ceramic blocks prolonging toward the periphery of the wall lining by one said refractory block.

10. The hearth as claimed in claim 8 , wherein the wall lining comprise, at the same level as said upper region, a first annular row of refractory blocks disposed circumferentially side by side, and a second annular row of microporous ceramic blocks disposed circumferentially side by side is disposed between the first annular row of refractory blocks and the large-size ceramic blocks disposed in a herringbone pattern.

11. The hearth as claimed in claim 1 , wherein the wall lining comprise, at the same level as said upper region, an first annular row of refractory blocks disposed circumferentially side by side, and the ceramic elements are large-size ceramic blocks disposed in concentric annular rows wherein each of said annular rows is constituted of microporous ceramic blocks disposed circumferentially side by side, the outer annular row of ceramic blocks being joined to the first annular row by a ramming material.

12. The hearth as claimed in claim 9 , wherein said refractory blocks are carbon blocks.

13. The hearth as claimed in claim 11 wherein the junction surfaces between adjacent ceramic blocks are progressively more globally inclined from the center toward the periphery of the bottom lining, so that any block is partially surmounting a block inwardly adjacent.

14. The hearth as claimed in claim 11 wherein the junction surfaces are flat inclined surfaces or curved slopped surfaces or stepped surfaces.

15. The hearth as claimed in claim 1 , wherein the ceramic elements are large-size ceramic blocks, measuring more than 200×400×500 mm, determining therebetween joints filed with ceramic mortar, a joint between any adjacent blocks having a width of 0.7 to 1.5% of the adjacent blocks dimension taken in the direction perpendicular to that of the joint.

Assignees

• Piret Jacques
• Kass Gilles
• Wurth Paul Sa

Inventors

• Piret Jacques
• Kass Gilles

Classifications

• B28B11/24

  for curing, setting or hardening (processes for influencing or modifying the setting or hardening ability of mortars, concrete or artificial stone compositions, in general C04B40/00) · CPC title

• C21B7/06 Primary

  Linings for furnaces · CPC title

• C21C5/44

  Refractory linings · CPC title

• F27D1/003

  Linings or walls comprising porous bricks · CPC title

• F23M5/00 Primary

  Casings; Linings; Walls · CPC title