US3894729A

US3894729A - Converter outlet lining

Info

Publication number: US3894729A
Application number: US439862A
Authority: US
Inventors: Hans Muller
Original assignee: Didier Werke AG
Current assignee: Didier Werke AG
Priority date: 1973-02-12
Filing date: 1974-02-06
Publication date: 1975-07-15
Anticipated expiration: 1992-07-15
Also published as: CA1015159A; BR7400997D0; ZA74929B; RO65031A; JPS568087B2; LU69367A1; FR2217423A1; BE810356A; JPS49112805A; CS190421B2; NL7401929A; FR2217423B1; ATA105174A; AR202118A1; GB1455373A; AT342634B; DE2306858C2; IT1008153B; DE2306858B1; ES423098A1

Abstract

A converter outlet lining includes a lower layer of highly conductive material such as carbon bricks, the outer edges of which are in contact with the jacket of the converter. An upper layer of wear resistant material includes a layer of magnesia bricks on top of the carbon bricks and spaced from the jacket, and a layer of compressed or compacted granular magnesite over the inner portion of the top of the magnesia bricks. Between the magnesia bricks and the jacket and over the outer portion of the top of the magnesia bricks is a layer of compressed or compacted granular highly heat conductive material such as carbon.

Description

United States Patent Muller 1 1 July 15, 1975 CONVERTER OUTLET LINING Primary ExaminerGerald A. Dost M [75] Inventor Hans Her, wlesbadn Germany Attorney, Agent, or Fzrm-Wenderoth, Lmd & Ponack [73] Assignee: Didier Werke AG, Wiesbaden,

Germany [22] Filed: Feb. 6, 1974 57 ABSTRACT [21] Appl. No.: 439,862

A converter outlet lmmg includes a lower layer of u highly conductive material such as carbon bricks, the [30] Apphcatlo Pnomy Data outer edges of which are in contact with the jacket of Feb. 12, 1973 Germany 2306858 the converter. An upper layer of wear resistant material includes a layer of magnesia bricks on top of the [52] US. Cl. 266/43 carbon bricks and spaced from the jacket, and a layer [51] Int. Cl. C21C 5/44 of compressed or compacted granular magnesite over [58] Field of Search 266/35, 43 the inner portion of the top of the magnesia bricks. Between the magnesia bricks and the jacket and over [56] References Cited the outer portion of the top of the magnesia bricks is UMTED STATES PATENTS a layer of compressed or compacted granular highly 117 248 7/1871 Bessemer 266/35 heat conductive material Such as Carbm 663,945 12/1900 Waldburger et a1. 266/43 FOREIGN PATENTS OR APPLICATIONS 5 Glam, 2 Drawmg 583,050 12/1946 United Kingdom 266/43 CONVERTER OUTLET LINING BACKGROUND OF THE INVENTION The present invention relates to an improved lining for the outlet area of converters or similar metallurgical vessels employing therein a highly heat conductive material, in particular carbon.

It is well known that heavy wear occurs at the outlet of the lining of a converter, such wear being considerably more rapid than the average wear of the remainder of the lining and being caused by a variety of reasons. The slag obtained during steel manufacture frequently possesses high iron-oxide fractions and also smaller fractions of metals, which fractions bind intimately with the outlet lining when the slag is poured over the edge of the outlet of the converter. There are thus formed deposits on the outlet lining that disturb operation and which consequently must be removed from time to time. The lining of the converter outlet is destroyed to a certain extent in this connection, so that patching operations are required, making it necessary to shut down the converter against schedule, thus resulting in additional costly down time.

In the past, in order to prevent the above-mentioned intimate connection between the slag and the lining at the converter outlet, the outlet portion of the converter which contacts the slag during pouring has been formed of carbon bricks that are highly heat conductive and possess a relatively low wetting effect in relation to slag, thereby rendering difficult any reaction between the slag and the outlet lining.

A further cause for the premature wear of the converter outlet opening lining in relation to the remaining lining is that the gases formed during the operation of the converter possess a relatively high fraction of CO which after-burns in the outlet of the converter, thus bringing about an excessive thermal stressing of the lining in such area. In order to remove the gases from the converter as much as possible without after-burning, and thus to avoid an excessive thermal stressing of the burner outlet, it has been suggested to increase the outflowing speed of the gases through the arrangement of a suction device. However, this proposal has not proven entirely satisfactory.

A further proposal for improving the useful life of the outlet lining by cooling the converter outlet has likewise not proven entirely satisfactory.

According to German published application (DT-OS) 1,433,508, the useful life of the lining of converters may be increased by providing the parts of the lining in contact with the jacket of the converter of highly heat conductive refractory material, preferably carbon or silicon carbide, at least in the thickness of the customary permanent lining of the converter. According to the exemplified embodiment of this publication, the lining in the outlet area of the converter consists exclusively of highly heat conductive carbon and/or silicon carbide. However, such proposal does not meet the requirements of current converter operation, since carbon cannot be employed in an oxidizing atmosphere above 400C (Harders/Kienow, page 876), and silicon carbide is not stable with respect to basic oxides at higher temperatures. Even oxide-free metal-melts attack SiC at l000-1200C (Harders/Kienow, page 868).

SUMMARY OF THE INVENTION The primary object of the present invention is to improve substantially and with simple means the useful life of converter linings in the outlet areas thereof, for the purpose of reducing extent of wear of the outlet lining to an amount equal to that of the remaining lining of the converter. This is achieved by employing refractory materials of high thermal conductivity, such as carbon, on the one hand, and materials having converter-operation-proven wear resistance, such as iron-poor sintered magnesia and sintered dolomite, on the other hand.

The invention consists basically in that the converter outlet lining includes an upper, lO0-60O mm thick outlet lining layer of wear-resistant material, and a lower, -400 mm thick layer of highly heat-conductive material, the outer peripheral surface of which contacts the metal jacket of the converter. Owing to such an arrangement of the converter outlet lining, a sufficient amount of heat is removed through the highly heat conductive layer, particularly from the wear resistant layer situated thereabove, that the slag flowing over the outlet lining during the tipping of the converter remains only loosely attached. There is formed a film-type slag coating, which can be readily removed from time to time without damaging the lining. Additionally, the layer of highly heat conductive material at the inner peripheral surface of the outlet is largely protected against the oxidizing atmosphere by the lining situated directly above and below, so that the wear of the highly heat conductive material, which occurs in such an atmosphere, is reduced to a negligible amount. All together, the wear-resistant arrangement or covering of the highly heat conductive layer results in a slag discharge which is free of problems while avoiding firm slag deposits which would lead to the destruction of the lining when removed, so that the desired adaptation of the wear of the outlet lining to that of the remainder of the lining is achieved.

The highly heat conductive layer consists advantageosly of carbon, and the covering layer arranged thcreabove consists advantageously of iron-poor sintered magnesia. This embodiment has proven to be particularly wear-resistant.

In the detailed arrangement of the outlet lining, there is provided according to the invention a layer of carbon bricks, on top of which there is arranged a layer of sintered magnesia bricks having a length of one third to two thirds of the width of the lining. The inner ends of the magnesia bricks are flush with the outlet opening. Above the layer of magnesia bricks is a layer of compressed or compacted granular magnesite extending from the outlet opening to the outlet flange of the converter. Peripherally outwardly of the magnesite material is a layer of compressed or compacted granular carbon material extending from the magnesite layer to the metal jacket of the converter. By a relative adjustment of the amount of highly heat conductive material behind the magnesite material, it is possible to adapt the heat removal capabilities to the operational conditions of the converter, and to thereby obtain a desired amount of outlet lining wear uniform with the wear of the remaining lining of the converter.

If the premature wear of the outlet lining occurs always in certain areas, a further proposal of the invention provides for the arrangement of highly heat conductive material only at the positions of premature wear, rather than through the entire lining of the outlet of the converter.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred exemplified embodiment of the invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a longitudinal section through the wall of a converter in the area of the outlet thereof; and

FIG. 2 is a sectional plan view taken along lines II-II in FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS In FIG. 1, the jacket 1 of a converter has supported thereon a double flange 4, defining an outlet 2, by means of brackets 3. The main converter lining 5 consists of a permanent lining 5', an intermediate layer 5" of compressed or compacted granular material and a wear lining 5" of magnesite and/or dolomite bricks. The lining 5 has on top thereof an outlet lining including a lower layer of carbon bricks 6 of a thickness of for instance 200 mm. The layer of bricks 6 is positioned 440 mm below the top of opening 2 and extends over the entire width of the lining, and the outer faces 7 of bricks 6 are in full and direct contact with jacket 1. A layer of magnesite bricks 8 is placed flush with the inner face of the outlet lining on top of the layer of carbon bricks 6. The magnesite bricks 8 are approximately half as long as carbon bricks 6. The free space peripherally outwardly of the magnesite bricks and below the converter flange 4 is filled with a layer 9 of compressed or compacted granular carbon material in such a manner to enclose the outer ends of the magnesite bricks 8 facing jacket 1. Over the remaining top surface of magnesite bricks 8 and extending peripherally inwardly of layer 9, there is positioned layer 10 of compressed or compacted granular magnesite material which defines the outlet of the converter with an inclined annular surface 11 extending upwardly and outwardly from the inner upper edge of magnesite bricks 8 to the inner upper edge of converter flange 4.

It will be apparent that by a suitable relative adjustment of the amount of the carbon material with respect to the covering magnesite material, the heat removal can be set to the desired operational conditions of a specific converter, and the wear of the outlet lining can thus be adapted to be equal to the wear of the remainder of the converter lining.

I claim:

1. An outlet lining for the outlet area of a metallurgical vessel, such as a converter, such vessel including a main lining, a metal jacket surrounding said main lining, and an outlet flange defining the outlet opening of said vessel, said outlet lining comprising:

a lower layer of highly heat conductive material, the outer surface of which is in direct contact with said metal jacket of said converter, said lower layer comprising layer of carbon bricks on top of said main lining, the innermost ends of which form a portion of said outlet and the outermost ends of which are in contact with said jacket; and

positioned on top of said lower layer, an upper layer of wear-resistant material, said upper layer comprising a layer of sintered magnesia bricks on top of said layer of carbon bricks, the length of said magnesia bricks being from one-third to two-thirds the length of said carbon bricks, the innermost ends of said magnesia bricks forming a portion of said outlet, there being a space between the outermost ends of said magnesia bricks and said jacket, and a layer of compressed granular magnesite material positioned over a portion of the top of said magnesia bricks, the inner surface of said layer of magnesite material forming a portion of said outlet.

2. An outlet lining as claimed in claim 1, wherein said lower layer has a thickness of from -400 mm, and said upper layer has a thickness of from 100-600 mm.

3. An outlet lining as claimed in claim 1, wherein said inner surface of said layer of magnesite material is inclined upwardly and outwardly from the inner upper edge of said magnesia bricks to an inner upper edge of said outlet flange.

4. An outlet lining as claimed in claim 3, further comprising a layer of compressed grannular highly heat conductive material positioned in said space between said outermost ends of said magnesia bricks and said jacket and over a portion of the top of said magnesia bricks, the outermost edge of said layer of compressed granular highly heat conductive material being in contact with said jacket.

5. An outlet lining as claimed in claim 4, wherein said compressed granular highly heat conductive material comprises carbon.

Claims

1. AN OUTLET LINING FOR THE OUTLET AREA OF A METALLURGICAL VESSEL, SUCH AS A CONVERTER, SUCH VESSSEL INCLUDING A MAIN LINING, A METAL JACKET SURROUNDING SAID MAIN LINING, AND A OUTLET FLANGE DEFINING THE OUTLET OPENING OF SAID VESSEL, SAID OUTLET LINING COMPRISING: A LOWER LAYER OF HIGHLY HEAT CONDUCTIVE MATERIAL, THE OUTER SURFACE OF WHICH IS IN DIRECT CONTACT WITH SAID METAL JACKET OF SAID CONVERTER, SAID LOWER LAYER COMPRISING LAYER OF CARBON BRICKS ON TOP OF SAID MAIN LINING, THE INNERMOST ENDS OF WHICH FORM A PORTION OF SAID OUTLET AND THE OUTERMOST ENDS OF WHICH ARE IN CONTACT WITH SAID JACKET, AND POSITIONED ON TOP OF SAID LOWER LAYER, AN UPPER LAYER OF WEAR-RESISTANT MATERIAL SAID UPPER LAYER COMPRISING A LAYER OF SINTERED MGNESIA BRICKS ON TOP OF SAID LAYER OF CARBON BRICKS, THE LENGTH OF SAID MAGNESIA BRICKS BEING FROM ONE-THIRD TO TWO-THIRDS THE LENGTH OF SAID CARBON BRICKS, THE INNERMOST ENDS OF SAID MAGNESIA BRICKS FORMING A PORTION OF SAID OUTLET, THERE BEING A SPACE BETWEEN THE OUTERMOST ENDS OF SAID MAGNESIA BRICKS AND SAID JACKET, AND A LAYER OF COMPRESSED GRANULAR MAGNESITE MATERIAL POSITIONED OVER A PORTION OF THE TOP OF SAID MAGNESIA BRICKS, THE INNER SURFACE OF SAID LAYER OF MAGNESITE MATERIAL FORMING A PORTION OF SAID OUTLET.

2. An outlet lining as claimed in claim 1, wherein said lower layer has a thickness of from 100-400 mm, and said upper layer has a thickness of from 100-600 mm.