EP0225548A2 - Brick for a bottom electrode, a rear lining or a hearth connection - Google Patents
Brick for a bottom electrode, a rear lining or a hearth connection Download PDFInfo
- Publication number
- EP0225548A2 EP0225548A2 EP86116468A EP86116468A EP0225548A2 EP 0225548 A2 EP0225548 A2 EP 0225548A2 EP 86116468 A EP86116468 A EP 86116468A EP 86116468 A EP86116468 A EP 86116468A EP 0225548 A2 EP0225548 A2 EP 0225548A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- brick
- bricks
- bottom electrode
- porosity
- rear lining
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B7/00—Heating by electric discharge
- H05B7/02—Details
- H05B7/06—Electrodes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D1/00—Casings; Linings; Walls; Roofs
- F27D1/0003—Linings or walls
- F27D1/0006—Linings or walls formed from bricks or layers with a particular composition or specific characteristics
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D1/00—Casings; Linings; Walls; Roofs
- F27D1/04—Casings; Linings; Walls; Roofs characterised by the form, e.g. shape of the bricks or blocks used
- F27D1/06—Composite bricks or blocks, e.g. panels, modules
- F27D1/063—Individual composite bricks or blocks
Abstract
Description
- The invention relates to a brick for a bottom electrode, a rear lining or a hearth connection according to the precharacterising part of
claim 1. - With this kind of bricks, the required combination of good electrical conductivity and good heat insulating poses a problem. Too good a heat insulation may often involve poor electrical conductivity and vice versa. Electric conduction at the bottom of a d.c. furnace is sometimes arranged by means of bricks or compounds containing graphite. However, the addition of graphite deteriorates the heat insulating capacity, whereby cooling and/or a thicker lining are required to avoid thermal overload of the furnace shell at the bottom or in the wall, or of the shell in a ladle wall.
- Insulating bricks with a varying degree of open porosity (50-90 %) are available on the market. In the case of d.c. furnaces (ladles) these bricks involve two decisive disadvantages. They are not electrically conductive and their mechanical strength is too poor for them to be used as rear insulating lining. Furthermore, gas flushing bricks with a directional open porosity are available on the market, but these bricks are electrically non-conductive.
- The invention aims at developing a brick of the above-mentioned kind, which combines good electrical conductivity, good heat insulating, and considerable mechanical strength.
- To achieve this aim the invention suggests a brick according to the introductory part of
claim 1, which is characterized by the features of the characterizing part ofclaim 1. - Further developments of the invention are characterized by the features of the additional claims.
- According to the invention, an electrically conductive, carbonaceous material has been added, completely or partially, to the open porosity.
- To achieve a continuous carbon conductor in pressed magnesite graphite bricks, 13 per cent by weight coal (#20 per cent by volume) is required at the present time. These bricks are to be regarded as chemically bound. In ceramically bound bricks with a porosity of about 20 %, it is presently possible to reach a content of carbonized residue of a maximum of 5 per cent by weight by means of impregnation. With a proper choice of the pore size of the grains and the viscosity of the coal carrying impregnating agent, it should be possible to obtain contents of carbonized residue of 13-23 % at a porosity of 50-90 %, which is sufficient to provide electrical conduction at the bottom of a d.c. arc furnace or ladle.
- The cold compression strength of chemically bound magnesite graphite bricks is 20-35 MPa and for insulating bricks about 2 MPa. With a combination of both types of binding, the mechanical strength after impregnation and heat treatment (carried out once or several times) is increased. Instead of impregnation, or complementary to impregnation, spray treatment can be carried out as well.
- The impregnating agent may, for example, consist of tar, pitch or resin, or of a suspension of graphite, soot or the like, or synthetic resin. The heat treatment is suitably carried out at a temperature when the binder is being coked, for example at 350 C or thereabove.
- In bricks having a directional porosity, such as gas flushing bricks, the channels are filled with a material which, in the same way as described above, is allowed to coke. Depending on the degree of filling and the degree of graphitization, a sectional surface of channels of 3-30 % may be sufficient for the bottom of a d.c. arc furnace.
- The invention will now be described in greater detail with reference to the accompanying drawings showing - by way of example - in
- Figure 1 a d.c. arc furnace, in which bricks according to the invention are employed,
- Figure 2 part of the bottom electrode (rear lining) of the d.c. arc furnace,
- Figure 3 a brick according to the invention.
- The d.c. arc furnace in Figure 1 is provided with an electrode having a hollow channel for reduction purposes. The
arc 1 is struck between the electrode and themelt 2.Numerals melt - Figure 2 shows the brick layers (3-5) in greater detail and also the
hearth connection 7. Eitherlayer 5 orlayer 6, that is, that part of the brick bottom or wall located nearest to the cold side, may consist of bricks according to the invention. - Figure 3 shows a pressed brick of aluminium oxides, magnesite, or zirconium oxide. As will be seen, the brick is porous, and the
open pores 8 have been impregnated with a carbonaceous material, for example pitch, tar, a suspension of graphite, soot or the like, synthetic resin, etc., for the purpose of achieving a carbon content in the brick which constitutes a conductor for the current, that is, the brick is electrically conductive while at the same time-its porosity provides for good thermal insulation. - By using bricks which are chemically or ceramically bound and have a porosity of about 20 %, a content of carbonized residue of at the most 5 per cent by weight can be attained by means of impregnation. With a porosity of 50-90 %, contents of carbonized residue of 13-23 % can be attained. Complementary to the impregnation, spraying of the bricks can be used. In certain cases, only spraying may be sufficient. The treatment can be carried out once or several times. As mentioned above, the cold compression strength of the chemically bound magnesite graphite bricks is 20-35 MPa and for insulating bricks about 2 MPa.
- The embodiment of the bricks according to the above may be varied in many ways within the scope of the following claims.
Claims (3)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE8505660 | 1985-12-02 | ||
SE8505660A SE456878B (en) | 1985-12-02 | 1985-12-02 | PROCEDURES FOR BUILDING A DIRECT LIGHT BAG |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0225548A2 true EP0225548A2 (en) | 1987-06-16 |
EP0225548A3 EP0225548A3 (en) | 1988-06-08 |
EP0225548B1 EP0225548B1 (en) | 1993-08-04 |
Family
ID=20362301
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP86116468A Expired - Lifetime EP0225548B1 (en) | 1985-12-02 | 1986-11-27 | Brick for a bottom electrode, a rear lining or a hearth connection |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0225548B1 (en) |
JP (1) | JP2605024B2 (en) |
DE (1) | DE3688830T2 (en) |
SE (1) | SE456878B (en) |
ZA (1) | ZA869000B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN107244930A (en) * | 2017-05-24 | 2017-10-13 | 方大炭素新材料科技股份有限公司 | A kind of resistance to molten iron corrodes blast furnace carbon brick and preparation method thereof |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4541099A (en) * | 1983-04-21 | 1985-09-10 | Asea Aktiebolag | DC Arc furnace improved hearth construction |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS50140509A (en) * | 1973-12-27 | 1975-11-11 | ||
JPS51105314A (en) * | 1975-03-12 | 1976-09-17 | Nikku Ind Co | Kaabondenkyoku taikarengatono pichishinkukaatsuganshinkaatsushoontankahoho |
IT1152141B (en) * | 1982-05-13 | 1986-12-31 | Caffaro Spa Ind Chim | PROCEDURE FOR THE CONTINUOUS PRODUCTION OF TETRACLORAFTALONITRILE IN A FLUID BED REACTOR |
-
1985
- 1985-12-02 SE SE8505660A patent/SE456878B/en unknown
-
1986
- 1986-11-27 EP EP86116468A patent/EP0225548B1/en not_active Expired - Lifetime
- 1986-11-27 DE DE86116468T patent/DE3688830T2/en not_active Expired - Fee Related
- 1986-11-28 JP JP61284106A patent/JP2605024B2/en not_active Expired - Lifetime
- 1986-11-28 ZA ZA869000A patent/ZA869000B/en unknown
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4541099A (en) * | 1983-04-21 | 1985-09-10 | Asea Aktiebolag | DC Arc furnace improved hearth construction |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN107244930A (en) * | 2017-05-24 | 2017-10-13 | 方大炭素新材料科技股份有限公司 | A kind of resistance to molten iron corrodes blast furnace carbon brick and preparation method thereof |
Also Published As
Publication number | Publication date |
---|---|
DE3688830D1 (en) | 1993-09-09 |
ZA869000B (en) | 1987-06-24 |
DE3688830T2 (en) | 1994-03-03 |
SE8505660D0 (en) | 1985-12-02 |
JPS62143888A (en) | 1987-06-27 |
JP2605024B2 (en) | 1997-04-30 |
EP0225548B1 (en) | 1993-08-04 |
SE456878B (en) | 1988-11-07 |
SE8505660L (en) | 1987-06-03 |
EP0225548A3 (en) | 1988-06-08 |
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