EP0043338A1 - Gas-permeable body of fire-resistant material - Google Patents

Abstract

For blowing a gas into a metal treatment vessel through its lining, structures are used which consist of at least two fire-resistant, fired or unburned, e.g. with a carbon carrier, such as tar, pitch, synthetic resin, bound or chemically bound material, existing segments (3) are constructed. At least one of the adjacent longitudinal segments is provided with a metal layer (4), possibly with surface protection. The segments (3) are combined by a common metal housing (2) which lies tightly against the longitudinal surfaces of the segments, possibly with the interposition of a layer of mortar. At least one connection (8) and a distribution space for the gas supply are arranged on an end face (7) of the structure.

Description

The invention relates to refractory, gas-permeable structures for blowing a gas into a metal treatment vessel through its lining.

The oxygen-blowing process used for pig iron freshening, which are known under the names "LD", "LDAC", "OLP", "BOF" processes, have recently been improved in metallurgical terms to the effect that secondary gases such as Nitrogen or argon, can be injected in a controlled manner. In other metal treatment vessels, such as pans for post-treatment of steel or electric arc furnaces, the blowing of gas into the metal bath through the vessel bottom or the lining of the vessel walls can also be considered.

1 The gas-permeable refractory bricks through which the gas is introduced are required to be inserted into the lining of the base or the side walls of the vessel, so that their durability corresponds to that of the other refractory linings, as a replacement of worn-out gas bubbles in the hot state, for example in one Converter floor is difficult. Furthermore, the introduction of gas should be possible both continuously and in particular discontinuously; i.e. the vessel should also be operable without the introduction of gas and after the gas supply is switched on again, the stones should be permeable to gas in an unchanged manner. In addition, the gas permeability of the stones over their service life, i.e. over an entire oven trip, remain essentially the same.

The previously known gas-permeable stones made of porous refractory material do not meet these requirements. Your shelf life in Fresh containers are much smaller than those of the surrounding lining material. Porous stones installed in an oxygen converter in the floor can withstand less than 100 batches, while the rest of the lining provides a shelf life of 500 batches and more. Furthermore, a discontinuous gas supply is not possible with porous stones; metal penetrates into the pores of the stones and solidifies there. When the gas supply is switched on again, the stone is no longer sufficiently gas permeable.

In patent application LU 81.208, the applicant has shown a device for blowing a treatment gas into a metal bath which is intended for insertion into the bottom of a metal treatment vessel and which has a noticeably improved durability compared to the gas-permeable stones known hitherto and allows the desired amounts of gas to be blown in. This device essentially consists of a refractory, gas-permeable structure, a plurality of flat, corrugated, tubular or wire-shaped metallic separating members of small wall thickness being embedded in the refractory material in the axial direction. According to one embodiment, this structure consists of steel sheets and segments or strips of refractory material in an alternating arrangement.

To manufacture such structures, a prefabricated block of refractory material has to be cut into the required strips or segments, which is a very complex manufacturing step. Since the segments generally have a small thickness and a large length, segments produced by pressing refractory material are not sufficiently manageable and warp if they are subjected to a stone fire.

An object of the invention is to improve the structure of such structures in such a way that simplified manufacture is possible and prefabricated segments with sufficient stability can be used.

Another task is to increase the gas throughput capacity without compromising the good durability of the structure.

According to the invention, these objects are achieved in that the structures consist of at least two fire-resistant, fired or unfired, e.g. segments composed of a carbon carrier such as tar, pitch, synthetic resin-bonded or chemically bonded material are built up, of which at least one of the adjoining longitudinal surfaces is provided with a metal layer, that the segments are combined by a common metal housing which is sealed to the longitudinal surfaces of the segments , optionally with the interposition of a mortar layer, and that at least one connection and a distribution space for the gas supply are arranged on an end face of the structure.

According to a first embodiment, the metal layers can be supports pressed with the refractory material.

The arrangement of pressed-in metal supports makes the manufacture and handling of relatively thin segments of great length considerably easier, since the metal support becomes a kind of reinforcement for the segments, which increases their stability. The use of segments or partial bodies with pressed-in metal supports also simplifies the assembly of several segments to form a single building structure, since the insertion of sheet metal plates is now unnecessary. Nevertheless, pairs of metal plates can be arranged between the segments if desired.

A second embodiment of the structure according to the invention provides that the metal layers lie against the refractory material, i.e. are not pressed with the material.

Be it that the metal layers are pressed together with the refractory material, or that they only lie against it, the structures according to the invention can be designed in such a way that the adjoining longitudinal surfaces of the segments have a smooth surface or a profiled, for example corrugated or grooved surface and also in such a way that the segments lie against one another with the interposition of metal plates, pairs of metal plates and / or spacers. The latter can be made from beads or knobs formed in the metal layers, from sheet metal strips, wires or from combustible or vaporizable deposits and the like. A further embodiment can consist in that a second support, for example a sheet metal plate, is attached, for example welded, to a metal layer which is also pressed in and that the adjacent longitudinal surface of the neighboring segment is free of metal layers.

The profiles, such as shafts, grooves, grooves or the like, can be formed in the longitudinal surfaces of the prefabricated segments made of refractory material by cutting or milling. However, it is also possible to form the profiles in the course of the production of the segments by the press die or the mold wall of the press mold used to produce the segments being equipped with the corresponding negative profile, as a result of which the profile is formed in the longitudinal surfaces when the segments are pressed.

The segments with co-pressed metal supports with a profiled surface can be produced in a simple manner by the pressing die or the mold wall having the corresponding profiling, e.g. Corrugation or creasing, is provided and an initially flat sheet metal plate and the refractory mass are introduced into the press mold. During the pressing process, the profiling is then automatically formed in the pressed sheet metal plate.

When assembling the segments provided with profiled metal supports, joints, channels are created in the structure through which the gas can pass, the profiled longitudinal surfaces being able to rest against both a smooth and a profiled longitudinal surface of the neighboring segment. The adjacent longitudinal surface of the neighboring segment can in turn be provided with a pressed-on metal support or it can be free of supports.

A further embodiment of the structure according to the invention can consist in that at least one co-pressed pair of adjacent metal inserts, for example sheet metal plates, is embedded in individual segments or in all segments. Spacers of the type mentioned above can be arranged between the metal plates of a pair of inserts. The extent of the gas permeability can be varied further by the number of pairs of inserts arranged in a structure and by their configuration with spacers.

In the case of these co-pressed insert pairs, the structure can be produced in a simple manner by first introducing part of the refractory material into the press mold, then inserting the insert pair, which extends over the entire stone length but only over a part of the stone width, and finally further refractory Material is filled. If the structure is to have more than one pair of inserts, this process is repeated accordingly. Then the pressing pressure is applied perpendicular to the inserts and the structure is thereby shaped. After removal from the press, the inserts on the end faces of the building are exposed to allow gas to pass through. Instead of a pair of plates, a folded sheet or a compressed tube can also be used. Multi-layer inserts, possibly with spacer elements, are also possible.

The extent of the gas permeability can be varied by the number of insert pairs arranged in a structure. Since the refractory material used for the building structure can correspond to that of the remaining lining, the building structure has the same durability as the lining surrounding it. An early renewal of the gas passage stones is not necessary.

As has been shown, the structures can also be operated without gas supply. While some metal penetrates into the narrow gap between the inserts of a couple, when the gas supply line is switched on again, this penetrated metal is flushed out of the structure and the original gas permeability is restored. This remains essentially the same over the entire service life of the structure.

• Die Fig. 1 eine erste mögliche Ausführungsform eines Baukörpers;
• die Fig. 2 bis 7 verschiedene Ausführungsformen von Segmenten;
• die Fig. 8 ein Ausführungsbeispiel eines mitzuverpressenden Einlagenpaares im vergrösserten Masstab;
• die Fig. 9 eine zweite mögliche Ausführungsform eines Baukörpers in dem Segmente gemäss der Fig. 6 zur Anwendung kommen und
• die Fig. 10 eine dritte mögliche Form, in der Segmente gemäss der Fig. 7 eingesetzt sind.

The drawings serve to explain the invention in more detail, in which some possible configurations of the structures according to the invention are shown in a non-restrictive manner. Show it:

• 1 shows a first possible embodiment of a building structure;
• Figures 2 to 7 different embodiments of segments.
• 8 shows an embodiment of a pair of inserts to be pressed in on an enlarged scale;
• 9 shows a second possible embodiment of a structure in which segments according to FIG. 6 are used and
• FIG. 10 shows a third possible form in which segments according to FIG. 7 are used.

The structure 1 shown in the figure has a e.g. Metal housing 2 constructed from welded plates, which surrounds a total of twelve segments 3, which are arranged in two rows of six pieces each. Each segment 3 has a co-pressed metal support 4 and lies with an unreinforced side surface with the interposition of a mortar layer, not shown, close to the inside of the metal housing 2. This prevents the undesirable, because uncontrollable, gas flow along the metal housing.

A sheet metal plate 5 is inserted between the two rows of the segments 3, along which a gas passage can take place, as well as along the metal supports 4 of the segments 3. Instead of the sheet metal plate 5, a pair of plates can also be arranged. Furthermore, the sheet metal plate 5 or the pair of plates can be mortared.

The segments 3 are spaced from the end face of the metal housing by means of two strips 6, which are arranged on the inside of the metal housing 2 and are preferably attached to it by spot welding. On this side, which represents the cold side, an end plate 7 is welded tight, which is provided with a pipe connection 8. The space remaining between the end plate 7 and the end faces of the segments 3 is the distribution space for the gas.

The opposite side of the front side 7, not visible, represents the fire side of the building and can be closed with a cover plate. The latter is used when the delivery of the metal treatment vessel surrounding the structure is tar or the like Contains carbon carrier. It then serves to prevent the penetration of tar or the like into the gas passage joints of the structure and the sticking of the same during the heating of the vessel. The cover plate melts at the start of operation and releases the joints. A bracket (not shown) can be attached in the area of the fire-side end face of the structure, by means of which the structure can be hung on a crane hook.

2, 3, 4, segments 30, 31, 32 are shown which are provided on two, three or four longitudinal surfaces with metal supports 4, 41, 42 which are also pressed together. The latter can be provided with punched claws 9 projecting into the refractory material for better connection to the refractory material. The cement 33 in FIG. 5 has a co-pressed metal support 4 and a second metal support 43 fastened to it by spot welding. The segments 30, 31, 32, 33 can be inserted into the structure according to FIG. 1 instead of the segments 3.

6 shows a segment 34, which is provided on one longitudinal surface with a profiled and indeed a corrugated metal support 44 and on the opposite longitudinal surface with a flat metal support 4. When two such segments 34 are assembled in a structure, channels for along the profiling are formed the gas passage.

FIG. 7 shows a segment 35 which can replace three segments 3 of the structure according to FIG. 1. This segment 35 is provided with a U-shaped co-pressed metal support 45 and two pairs of sheet metal inserts 10, which extend over the entire length but only over part of the width of the segment 35. Depending on the desired gas permeability, these inserts 10 can be designed as smooth sheet metal strips or, as shown in FIG. 8, as sheet metal strips provided with spacers, such as beads or grooves 11. To improve the connection between the stone mass and the inserts 10, these can be provided with claws 9.

The structure 1 shown in FIG. 9 has a metal housing 2 which surrounds twelve segments, each in two rows of six pieces are arranged. Each segment is provided with a profile on a longitudinal surface, specifically a profile in the form of grooves in the upper segments 34a and one in the form of waves in the lower segments 34. In practice, however, the same type of profiling will be used for all segments.

Flat sheet metal plates are inserted in the joints between two segments of a row; but the insoles can also be profiled. be provided. An insert in the form of a pair of sheet metal plates is shown between the two rows.

The building body 1 shown in FIG. 10 has a metal housing 2 which surrounds four segments 35. These four segments lie against one another with their U-shaped, pressed-in metal supports 45, whereas the unreinforced long sides of the segments lie against the inside of the housing, which e.g. is made from welded plates.

Sheet metal is particularly suitable as the material for the metallic inserts, e.g. in a thickness between 0.5 and 3 mm, which can optionally be provided with a surface protection.

Der Sintermagnesia werden 4 Gew.-% Steinkohlenteerpech als Bindemittel zugesetzt. Als Bindemittel kommen auch andere Teere, Peche, Kunstharze od.dgl. in Betracht.For example, the structure can be made from a tar-bound magnesia mass with the following composition and grain structure:

4% by weight of coal tar pitch are added to the sintered magnesia as a binder. Other tars, pitches, synthetic resins or the like also come as binders. into consideration.

Korngrössen

A further production of a stone suitable for use in a structure according to the invention has the following composition and the following grain structure:

Grain sizes

The components are mixed with 3.7% by weight kieserite solution with a density of 1.22 g / cm3 for chemical bonding.

However, the invention is not limited to the refractory materials mentioned. Other refractory materials, e.g. Mixtures of magnesia and chrome ore, tweeter material are used.

The structures according to the invention have sufficient gas permeability, the passage of gas taking place on the one hand through the joints between the individual segments and on the other hand through the joints between the metal inserts. The segments themselves have practically no gas permeability, and therefore the refractory material used for the structure can correspond to that of the rest of the lining of the metal treatment vessel. As a result, the gas-permeable structures have the same durability as the lining around them, and one before It is not necessary to renew the gas-permeable structures at an early stage.

According to the invention, a metal plate is generally provided in each joint of the structure through which gas is to pass, whether in the form of metal layers on the segments or in the form of metal plates arranged between the segments. As said, these metal plates or supports prevent the penetration of metal from the metal bath of the treatment vessel into the joints, even in the case of the treatment of pig iron, which due to its consistency and viscosity has a particularly strong tendency to penetrate into the joints.

This phenomenon may be explained by the fact that the metal plates arranged in the gas-permeable joints exert a cooling effect and quickly dissipate the heat to the cold end face of the structure. As a result, penetrating treatment metal solidifies after a short distance (a few cm). In the case of joints without metal plates or coverings, however, the penetration of treatment metal up to the cold face was observed.

Claims (10)

1. Fireproof, gas-permeable structure for blowing a gas into a metal treatment vessel through its lining, characterized in that it consists of at least two, adjacent to one another on longitudinal surfaces, made of fireproof, fired or unfired, e.g. segments 3 consisting of a carbon carrier, such as tar, pitch, synthetic resin, bound or chemically bound material, of which at least one of the adjoining longitudinal surfaces is provided with a metal layer 4, that the segments 3 are combined by a common metal housing 2, that lies tightly in the longitudinal surfaces of the segments, possibly with the interposition of a layer of mortar, and that at least one connection 8 and a distribution space for the gas supply are arranged on an end face 7 of the structure. 2. Building structure according to claim 1, characterized in that the metal layers 4 are pressed with the refractory material. 3. Building structure according to claim 1, characterized in that the metal layers lie against the refractory material. 4. Building structure according to claims 1-3, characterized in that the longitudinal surfaces of the segments and that of the metal layers, smooth 4 or profiled 44, e.g. can have corrugated 34 or grooved 34a surfaces. 5. Structure according to claims 1-4, characterized in that a further metal layer e.g. is attached by welding, the adjacent longitudinal surface of the neighboring segment of metal layers being free. 6. Building structure according to claims 1-5, characterized in that in the segments 35 at least one co-pressed pair of adjacent metal inserts 10, e.g. Sheet metal plates, optionally with the interposition of spacers, is embedded. 7. Structure according to claim 6, characterized in that the spacers (Fig. 8) consist of beads or knobs II formed in the metal layers, of wires, metal strips, or of combustible or vaporizable deposits. 8. Building structure according to claims 1-7, characterized in that the metal layers consist of sheet steel, which can be provided with a surface protection. 9. Structure according to claims 1-8, characterized in that the metal layers and the spacers to improve the hold in the refractory material are provided with claws 9. 10. Building structure according to claims 1-9, characterized in that a metal layer is generally arranged in each joint of the building structure through which a gas passage is to take place.

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