MXPA99006951A

MXPA99006951A - Refractory wall, metallurgical vessel comprising such a refractory wall and method in which such a refractory wall is applied

Info

Publication number: MXPA99006951A
Application number: MXPA/A/1999/006951A
Authority: MX
Inventors: Van Laar Jacobus; Jozef Tijhuis Gerardus
Original assignee: Hoogovens Staal Bv
Priority date: 1997-01-29
Filing date: 1999-07-27
Publication date: 2000-01-01

Abstract

Refractory wall structure, suitable in particular for use in a metallurgical vessel for a continuous production of crude iron in a smelting reduction process under conditions of an extremely high thermal load in a highly abrasive environment of molten slag with a high FeO content, comprising, going from the outside to the inside, (1) a steel jacket (6);(2) a water-cooled copper wall (7);(3) water-cooled copper ledges (8) extending towards the inside;(4) a lining of refractory material (10, 11) resting on the ledges (8).

Description

REFRACTORY WALL, METALLURGICAL RECIPIENT THAT COMPRISES SUCH REFRACTORY WALL AND METHOD IN WHICH SUCH WALL IS APPLIED REFRACTORY DESCRIPTION OF THE INVENTION The invention relates to a refractory wall structure, suitable in particles for use in a metallurgical vessel for continuous production of crude iron in a melt reduction process under conditions of an extremely high thermal load in a highly abrasive molten slag environment. with a high content of FeO. The invention also relates to a metallurgical vessel and to a method for the continuous production of crude iron, in particular for the final reduction of the melt reduction process in a cyclone converter furnace (CCF). According to the state of the art, crude iron is produced in a blast furnace. In this process iron ore is reduced with the help of coke. There are different processes that have been developed for the direct reduction of iron ore which, however, have not yet been applied industrially. The most promising are those that are called processes of reduction by fusion in bath. A bottleneck with these processes is the service life of the refractory wall structure of the metallurgical vessel in which the reduction in crude iron takes place. This is determined by a particularly high thermal load and a highly abrasive environment due to the presence of FeO at a temperature level of approximately 1700 ° C. In the case of a blast furnace where the same conditions are present in a slightly less aggressive form and for which a thermal load of 300,000 W / m2 can be presented, the refractory wall structure consists, in its most threatened place, going from the outside to the inside, from a reinforcing armor and a lining of refractory bricks, for example bricks containing SiC which are cooled by cooling elements. The cooling elements according to the state of the art are what are called cooling plates, which become easily removable in the coating, as described in the Netherlands patent application NL 7312549 A, or what is they call rollers which form a water-cooled wall between the armor plate and the lining. Currently with this structure it is possible to reach a service life of the order of 10 years. The application for European patent EP 0 690 136 Al describes an apparatus in which iron compounds in the form of particles are melted in this apparatus which is cooled by water. With the melt reduction process, the thermal load is much higher and can even reach 2,000,000 W / m2 locally. Therefore, an acceptable service life can not be obtained with a known wall structure for a blast furnace.

The object of the invention is to provide a wall structure for a direct reduction process which has an acceptable service life. This is obtained according to the invention with a wall structure comprising, directing from the outside to the inside, (1) a steel cover; (2) a copper wall cooled with water; (3) copper slopes cooled with water that extend inwards; (4) a coating of refractory material that rests on the shoulders. With this basic structure it is possible, due to the maximum thermal contact between the coating and the copper wall cooled with water and the shoulders, to manufacture a refractory wall structure with which a low thermal resistance is obtained. As a result of this, even under a high thermal load, a good stable residual coating thickness is obtained, resulting in a prolonged service life. The most threatened area in the metallurgical vessel in which iron ore reduction takes place is where the molten slag layer which contains a high amount of FeO floats on the raw iron bath. There the lining is removed by wear to a balanced residual thickness over which a layer of slag solidifies the layer which functions as a layer of wear and insulation. The solidified layer prevents the coating from being attacked and the structure is able to withstand an additional attack. The cooling by the shoulders improves the service life of the refractory structure. Preferably, the projections are vertically movable. The advantage of this is that, when assembled cold, the refractory wall structure can settle in the vertical direction under the effect of its own weight so that the horizontal joints close as much as possible. Preferably, the ridges in the upper part extend upwards, inwards obliquely, the projections in the bottom extend downwards, inwards obliquely, and the projections are distributed upwards to the height of the wall. The advantage of this is that the coating is fixed in relation to the copper wall cooled with water. Preferably, the cooled copper wall is constituted of panels. This facilitates the fabrication of the water-cooled copper wall assembly. Preferably, the shoulders are installed alternately in height to width and / or circumference. This has the effect that the pipes of the cooling water fed and the discharge pipes are distributed uniformly through the steel cover and groups of them are avoided.

Preferably, the coating is supported without mortar on the shoulders and the coating rests against the wall cooled with water without mortar. This avoids the high thermal resistance as a consequence of the joints filled with mortar, and it is possible to allow a high thermal load. Preferably, the coating is composed of graphite blocks with a coefficient of thermal conductivity in the range of 60-150 W / m ° K and / or blocks of semigraphyte with a coefficient of thermal conductivity in the range of 30-60 W / m ° K. As a result of the high coefficient of thermal conductivity, a low thermal resistance is obtained, as a cause of which it is possible to allow a high thermal load. In an alternative embodiment, the coating preferably consists of refractory bricks, most preferably of the cross-bars of a type that is used in converters for the production of steel or in electric furnaces for steel production, and more preferably the bricks are magnesite-carbon bricks. Bricks of this type known for steel production have a high resistance to abrasion. Preferably, going from the outside to the inside, the coating consists of a layer of graphite which rests against the copper wall, and a wall of the refractory bricks. With this modality, once the balanced thickness has been established in itself, the coating consists of a layer of refractory bricks resistant to wear and a layer of graphite with a low thermal resistance. Preferably, the wall is tilted back from the bottom toward the top. This improves the stability of the coating. In addition, this enlarged form obtains the effect that the level of the slag layer in the metallurgical vessel varies less. Preferably the copper wall and / or copper bosses consist of red copper with a content of > 99% Cu and a coefficient of thermal conductivity in the range of 250-300 W / m ° K. This generates an acceptably low thermal resistance of these elements. Preferably, the steel cover forms part of a pressure vessel and the conduits through the steel covers of the cooling water supply and the copper wall discharge pipes cooled with water and the copper shrouds cooled with water. water is sealed after the assembly of the wall. This generates the effect that the process can be carried out under a state of overpressure. Preferably the wall is resistant against a thermal load of more than 300,000 W / m2, and against a slag with about 10% by weight of FeO at a temperature level of about 1700 ° C, and the wall has a service life of at least minus 6 months of continuous use. This allows the wall to operate under conditions of high thermal load in a highly abrasive environment with an acceptable service life. In another aspect, the invention is constituted by a metallurgical vessel, in particular for the final reduction of a melt reduction process in a cyclone converting furnace (CCF) comprising a refractory wall structure according to the invention. In a further aspect, the invention is constituted by a method for a continuous production of crude iron, in particular for the final reduction of the melt reduction process of cyclone converter furnace (CCF) in a metallurgical vessel in which it is applied. a refractory wall structure according to the invention. The invention will now be illustrated in the following with reference to the non-limiting drawings. Figure 1 shows a mounting of the refractory wall structure in a vertical cross section. Fig. 2 shows a view of the refractory wall structure according to arrow I in Fig. 1. Fig. 3 shows a sub-assembly of a copper wall panel cooled with water and a copper shoulder cooled with water in a state not assembled Figure 4 shows a sub-assembly of a copper wall panel cooled with water and a shoulder cooled with water, in an assembled state. Figure 5 shows a detail of the seal of a cooling water supply duct or a discharge pipe in the steel cover. The drawing shows the invention in a modality which is developed for a metallurgical vessel in which the reduction to crude iron takes place by means of the melt reduction process of the cyclone converter furnace (CCF). However, the invention is not limited to that application and is also suitable for application in other processes to reduce iron ore with a high thermal load and / or with a highly abrasive environment due to FeO. Figure 1 shows a structure ( 1) of refractory wall according to the invention forming part of a metallurgical vessel. The number (2) indicates the level of the slag layer floating in the metallurgical vessel in a bath (3) of raw iron, and numbers (4) and (5) indicate the minimum and maximum levels of the slag layer , respectively. The refractory wall structure comprises a cover (6) of steel, a wall (7) of copper cooled with water, shoulders (8) cooled with water and a coating (9), which, in the case of figure 1, consists of blocks (10) of graphite and refractory bricks (11).

It is shown that in the case of Figure 1, the refractory wall structure is tilted in relation to the vertical V from the bottom to the top. In the direction of its height, the wall (7) of copper cooled with water consists of two panels (12) and (13). Each panel is provided with four projections (8). Six blocks of graphite are placed between each two shoulders. On the front of these graphite blocks an equal number of refractory bricks is placed in each case. The steel cover (6) continues above and below the refractory wall structure and on the inside of the metallurgical vessel is also provided with a refractory structure (14) and (15), the nature of which according to this The request is not very relevant. The weight of the structure (1) of the refractory wall is supported at least in part by the refractory structure (15) below it. Panels (12) and (13) are provided internally with ducts (16) of cooling water with couplings (17) and (18) for the supply and discharge of cooling water which is transported towards the exterior of the container metallurgical through the cover (6) of steel. The ledges (8) are also provided internally with a duct (19) of cooling water with a coupling (20) of cooling water to the outside of the metallurgical vessel. It is shown that the shoulders (8) in the upper part run upwards obliquely inwards and in the lower part run downwards, obliquely inwards. In contrast to the wall structure as they are known for a blast furnace where the lining of the refractory bricks are joined with mortar, the lining (9) rests on the shoulders (8) without mortar and is supported without mortar against the wall (7) cooled with water. The wall (7) cooled with water and the shoulders (8) are made of red copper with > 99% Cu. The graphite blocks (10) have a coefficient of thermal conductivity in the range of 60-150 W / m ° K. The refractory bricks (11) are magnesite-carbon bricks. Figure 2 shows a part of the circumference of the refractory wall structure whereby the covering (9) is omitted. The part comprises four panels (12A), (12B), (13A), and (13B), each of which is approximately 2.4 m high and 1 wide. The shoulders (8) are alternated in height in the direction of the circumference. The number of cooling water supply and discharge ducts (17) and (18) shown in panel (21) of figure 3 having four internal cooling ducts. It is shown that, in order that the cooling water supply and discharge ducts (20) of the shoulder (8), the recesses (22) are placed in the cooling panel (21), of which only is shown one set in figure 3 (in figure 1 there are four ledges (8) per panel).

Figure 4 shows a cooling panel (21) and a shoulder (8) in an assembled state. Figure 5 shows the conduit of a cooling water tube (20) of the shoulder (8) through the panel (21) and the steel cover (6), so that after the cooling assembly of the structure of refractory wall, the seal takes place with the help of the plate (24) which is welded to the tube (20) and the steel cover (6). A concrete lining can be placed between the panel (21) and the steel cover (6) 10. The remaining space (25) in the free space between a side tube (20) and the panel (21), the concrete (23) and the cover (6) on the other side, is filled with mortar or felt. A refractory wall structure according to the invention is resistant to a thermal load greater than 300,000 W / m2 and slag with approximately 10% FeO at a temperature level of 1,700 ° C with a service life of at least six months. In this way the effect is obtained that the metallurgical vessel, or at least its slag zone, does not needs to be changed or repaired frequently, but rather a service life comparable to that of a modern blast furnace is obtained.

Claims

CLAUSES

1. Refractory wall structure, suitable in particular for use in a metallurgical vessel for the continuous production of crude iron in a melt reduction process under conditions of an extremely high thermal load in a highly abrasive molten slag environment, with a high content of FeO, which comprises, going from the outside to the inside: (1) a steel cover; (2) a copper wall cooled with water; (3) copper slopes cooled with water that extend inwards; (4) a coating of refractory material that rests on the shoulders.

2. Refractory wall structure as mentioned in clause 1, where the projections are movable vertically on the wall assembly.

3. Refractory wall structure as mentioned in clauses 1 or 2, where in the upper part of the projections they extend upwards, inwards obliquely.

4. Refractory wall structure as mentioned in clauses 1 to 3, where at the bottom of the projections extend downwards, inwards obliquely.

5. Refractory wall structure as mentioned in clauses 1 to 4, where the projections are distributed over the height of the wall.

6. Refractory wall structure as mentioned in clauses 1 to 5, where the copper wall cooled with water is made up of panels.

7. Refractory wall structure as mentioned in clauses 1 to 6, where the shoulders are alternated in height to the width and / or circumference.

8. Refractory wall structure as mentioned in clauses 1 to 7, where the lining rests on the shoulders without mortar.

9. Refractory wall structure as mentioned in clauses 1 to 8, where the lining rests against the wall cooled with water without mortar.

10. Refractory wall structure as mentioned in clauses 1 to 9, where the cladding consists of graphite blocks with a coefficient of thermal conductivity in the range of 60-150 W / m ° K.

11. Refractory wall structure as mentioned in clauses 1 to 9, where the coating is composed of blocks of semigraphyte with a coefficient of thermal conductivity in the range of 30-60 W / m ° K.

12. Refractory wall structure as mentioned in clauses 1 to 9, where the lining consists of refractory bricks.

13. Refractory wall structure as mentioned in clause 12, where the bricks are of a type that is used in converters for steel production or in electric furnaces for steel production.

14. Refractory wall structure as mentioned in clauses 12 or 13, where the bricks are magnesite-carbon bricks.

15. Refractory wall structure as mentioned in clauses 1 to 14, where, going from the outside to the inside, the cladding consists of a layer of graphite which rests against the copper wall and a layer of refractory bricks.

16. Refractory wall structure as mentioned in clauses 1 to 15, where it tilts backwards from the bottom to the top.

17. Refractory wall structure as mentioned in clauses 1 to 16, wherein the copper wall and / or the copper lugs consist of red copper with a content of > 99% Cu and a coefficient of thermal conductivity in the range of 250-300 W / m ° K.

18. Refractory wall structure as mentioned in clauses 1 to 17, where the steel cover forms part of a pressure vessel and the ducts through the steel cover of the cooling water supply and discharge pipes of the copper wall cooled with water and water-cooled copper lugs are sealed after wall mounting.

19. Refractory wall structure as mentioned in clauses 1 to 18, where it is resistant against a technical load of more than 300,000 W / m2 and against slags with approximately 10% by weight of FeO at a temperature level of approximately 1700 ° C.

20. Refractory wall structure as mentioned in clauses 1 to 19, where it has a service life of at least six months of continuous use.

21. Metallurgical vessel, in particular for use in the final reduction of the melt reduction process of a cyclone converter furnace, in which it comprises a refractory wall structure, which in itself comprises, going from the outside to the inside: (1) a steel cover; (2) a copper wall cooled with water; (3) copper slopes cooled with water that extend inwards; - (4) a coating of refractory material that rests on the shoulders; as mentioned in one of clauses 1 to 20.

22. Method for the continuous production of crude iron, in particular for application in the final reduction of a melt reduction process in a cyclone converting furnace in a metallurgical vessel, where it is applied in a refractory wall structure as mentioned in a of clauses 1 to 20.