UA5935U - An apparatus for introducing inert gas into the metal melt - Google Patents

Abstract

An apparatus for introducing inert gas into the metal melt with gases contains metal case, walls lining, bottom lining which consists of reinforcing, working layers and gas-distributing layer placed in the deepening reinforcing layer of the bottom. Between bottom of the deepening and gas-distributing layer gastight box is additionally disposed in which layer is made of refractory material with thickness less by 15-35 mm than that of reinforcing layer, and leads, at that above the layer between leads a gas-distributing stratum is placed, on which working lining with gas-permeable seams of capacity bottom is supported.

Description

A useful model refers to ferrous metallurgy, specifically to the treatment of liquid metal with gases.

A well-known device for introducing inert gas into a ladle with melt, which contains a spirally curved pipe placed in the lining of the bottom with evenly spaced, upwardly directed holes of the same diameter (A.S.

USSR Me1211304, cl. 321С7/06, publ. 15.02.86).

The known device does not allow you to make a uniform metal blowing mode, because through holes of the same diameter, the greatest intensity of gas supply to the metal will occur at the beginning of the spiral and the minimum - at its end. In addition, the exit of gas through the vertical seams of the worker layer with ferrostatic pressure is more difficult than through the horizontal seams. At the same time, it is impossible not only to exclude gas losses due to seepage through the reinforcing layer, but also to control these losses, and without accurate accounting of the gas consumption for purging, it is impossible to comply with the technological parameters of off-fire refining. In addition, it is very difficult and time-consuming to lay the lining in the presence of pipes, because it is necessary to supply bricks (undercutting of bricks, in which it is completely unrealistic to comply with the requirement of the instructions for the thickness of the seams to be no more than 1.5 mm), therefore, the fulfillment of the condition for the gas tightness of the seams of the reinforcing layer is unrealistic .

A well-known ladle for blowing metal with gases, containing a lined casing with a bottom lining of two horizontal layers, one of which is made of fire-resistant bricks with porous seams, and the other - of porous mass, and a nozzle for gas supply, and a layer of porous mass in the bottom lining made of granulated material and placed between the casing and a layer of refractory bricks (AS USSR Moe578160, class B22DA1/02, publ. 10/30/77).

Bucket according to the a.s. Me578160 does not allow to achieve the expected technical result. The stability of the purging process is largely determined by the total length of vertical and horizontal seams, which in turn determines the amount of pressure required for the passage of gas through the seams. The higher the required pressure, the more uncontrolled seepage of gas between the bucket armor and the lining. In the well-known ladle, both the worker and the reinforcement layers are gas-permeable, the considerable length of the porous seams does not allow them to achieve stable gas permeability along the entire length. In addition, the considerable length of the porous seams increases the resistance to the passage of gas and requires increased gas pressure in the gas distribution layer. Increased gas pressure under the lining leads to an increase in the volume of gas, which goes beyond the porous seams into the lining of the walls and further - into the gaps between the lining of the walls and the casing.

All this has a negative effect on the quality of metal gas treatment.

In addition to the disadvantages of the ladle, which negatively affect the technology of metal gas treatment, there is a drawback that worsens the operational qualities of the ladle. This drawback is due to the fact that in the prototype ladle, the gas-distributing granular layer plays the role of a leveling layer, its thickness reaches 60-100 mm.

A granular layer of this thickness has a tendency to shift when the bucket is tilted to the side of its slope. During the operation of such buckets, there have been cases of the lining of the bottom resting on the edger side.

Of the known containers for blowing liquid metal with gas, the closest in terms of technical essence in achieving the result is the metallurgical container for blowing liquid metal with gases (Declaratory patent for the invention

Mo49775 class AV22041/00, published on September 16, 2002. Bul. Me9) retaining metal casing, wall lining, bottom lining made of reinforcement and worker layers, and gas distribution layer of granular material.

The reinforcing layer is made of gas-tight refractory material, and the gas distribution layer is located between the working and reinforcing layers in the recess of the latter.

The disadvantages of such a container are: - high residual gas permeability of the gas-tight refractory solution, on which the lining of the reinforcing layer is laid. This is caused by the fact that a lot of water (up to 2095) is kept in the mortar. When drying the container, moisture is removed and leaves through pores through which vapors were evacuated. The second reason that leads to the inevitable formation of pores is the shrinkage of refractory clay during drying, which is a necessary component and is added as a binder to the solution; - the low mechanical strength of the seams of the masonry lining of the reinforcement layer leads to cracking of the seams during transportation and installation of the container, at the same time, gas-permeable gaps between the bricks are formed. Examination of the samples of the refractory reinforcing layer, taken when the layer was changed by the worker, showed that the structure of the seams contains many micro and macro cracks. The gas permeability of such seams during operation increases tenfold. This especially applies to horizontal and vertical seams in the side walls of the gas distribution layer.

The purpose of the useful model is to prevent gas from escaping through the bottom of the container and to maintain the stability of the purge parameters of the gas injection device during the inter-repair period of the metallurgical container.

The useful model is based on a technical task: to improve the device for introducing inert gas into the molten metal by changing the design of the gas distribution unit, which consists in installing a box made of a thin sheet of gas-tight material, for example, metal in a recess in the reinforcing layer and two additional layers on the bottom of the box: the first layer made of refractory material, 15-35 mm less thick than the reinforcing layer and the installation of intermediate beacons between the metal box and the working layer of the lining of the bottom of the container, the second gas distribution layer consisting of granular material.

Common features of the useful model with the prototype are: - metal casing; - wall lining; - lining of the bottom, consisting of reinforcement and worker layers; - gas distribution layer consisting of granular material; - deepening in the reinforcing layer; - gas supply device.

The significant features of the invention that distinguish it from the prototype are: - the location of the gas-tight box on the bottom of the recess in the reinforcement layer in the area of the gas distribution layer;

- laying on the bottom of the gas-tight box, layering the refractory with a thickness less than 20-40 mm of the reinforcing layer. - installation of intermediate beacons between the metal bottom of the box and the working lining of the bottom of the container.

The set of essential properties of a useful model is necessary and sufficient for all cases to which the scope of use of a useful model extends.

An alternative feature of a useful model is the presence of a leveling layer of bulk material on which the reinforcing layer is placed.

Among the essential features of the useful model and the technical result are the installation of a gas-tight box in the recess of the reinforcing layer and the location on it of a refractory layer with a thickness of 15-35 mm less than the reinforcing layer, the installation of an intermediate layer and the prevention of gas leakage through the bottom and side walls of the gas distribution layer and the preservation of the stability of the blowing parameters during the interrepair period of the metallurgical capacity there is a cause and effect relationship. This connection is explained by the following evidence: when laying a gas-tight box on the bottom of the recess in the reinforcing layer, complete isolation from gas leakage occurs through the lining of the reinforcing layer of the bottom of the container not only through vertical seams, but also through the horizontal seam between the reinforcing and working layers, because even with the formation of cracks in the refractory, the gas-tight box will prevent the gas from seeping through them during the blowing of the liquid metal. Placing a refractory layer and intermediate beacons on the bottom of the gas-tight box will allow you to fulfill three tasks: the first is to obtain a guaranteed thickness of the gas distribution layer of 15-35 mm, the second is to prevent the impact of high temperatures on the gas-tight box and, as a result, its warping or destruction, and the third is to fix the box in the reinforcement layer prevents failure of the gas distribution system in the event of extreme situations.

The thickness of the gas distribution layer in the range of 15-35 mm allows you to evenly distribute the gas pressure under the entire gas-permeable area of the worker layer. Reducing the thickness of the gas distribution layer below 15 mm leads to an uneven distribution of pressure between the place of gas supply and the periphery of the gas distribution collector during the maximum intensity of purging during melt homogenization. This will be especially evident on heavy-duty buckets with a large collector. When the thickness of the gas distribution layer is more than 35 mm, there is a danger of the precipitation of granular material, its displacement to the side of the slope of the container and uneven gas permeability of the gas distribution layer, which in turn will lead to uneven passage of gas through the gas permeable lining of the bottom of the container.

In Fig. a cross-section of the device for introducing inert gas into the melt is shown schematically. The device has a casing 1, leveling layer 2, consisting of loose refractory material fraction 0-Zmm. The lining of the walls and the lining of the bottom 3, consisting of a reinforcing layer 4, with a recess 5. A reinforcing layer made of a fire-resistant gas-tight material and placed on a leveling layer 2. A gas-tight box 6, placed on the bottom of the recess 5, on top of it a fire-resistant layer 7 with beacons 8. gas distribution layer 9, made of granular material of fraction 4-zdmm, located on a refractory layer 7

The thickness of layered granulated material 9 is 20-40 mm. The working layer 10 of the lining of the bottom 3, which is located directly on the gas distribution layer 9, is a brickwork with porous gas-permeable seams. Gas supply device 11, which is a metal pipe with a diameter of 50-60 mm, filled with granular refractory material with a fraction of 10-15 mm, and the output upper end into the gas distribution layer. The lower end is attached to the metal casing of the bottom of the container and is connected to the external gas supply pipe 12.

The device works in this way. The device is connected to the gas pipeline system with the help of a connecting pipe 12. The gas through the nozzle 12 and the gas supply device 11 enters the gas distribution layer 9 where, thanks to the granular material, it is evenly distributed throughout the entire volume of the layer 9. As the pressure in the layers 9 increases, the gas tends to seep through the open pores of the refractory bottom of the recess 5. Thanks to the gas-tight casing 6 the bottom of the recess 15 is completely, regardless of the pressure, isolated from seepage of gas into the reinforcing layer 4 of the bottom of the container and further into the environment. When the gas pressure is higher than ferrostatic, gas escapes into the melt volume only through the gas-permeable seams of the layer 10 worker

When filling a metallurgical container with liquid metal, especially at the initial moment, there is a hydrodynamic effect on a relatively small area of the bottom (a column of liquid metal with a diameter of 0.2-0.3 m and a weight of 1-2.5 tons falls from a height of 3-5 m). Thanks to the beacons 8, the working layer 10 does not deform under hydrodynamic influence and does not seal the gas distribution layer 9 under it, which prevents the destruction of gas-permeable seams. The homogeneity of the gas distribution of the layer 9 is preserved throughout the entire volume, therefore, the stability of the uniform passage of gas during the blowing of liquid metal in the technologically specified mode is ensured. In addition, the beacons 8 prevent the movement of the interlayer 9, which also preserves the stability of the material properties of the interlayer 9 throughout the entire volume.

Under the influence of high temperatures, the gas-tight box 6 warps. When the bottom of the box rests upwards (heated from above), the material of layer 9 is pressed and its properties are disturbed.

When installing a non-metallic gas-tight box, under the influence of sharp cooling, it may crack and lose gas-tightness. Refractory layer 7 and interlayer 9 perform two functions: the first is pinching the gas-tight bottom of the box b from above, which will allow it to be fixed in the plane, the second is thermal insulation, which will significantly reduce the thermal effect on the box b, which in turn prevents its warping or cracking. In addition, when the cold gas passes through the interlayer 9, cooling occurs not only of it, but also of the walls of the cavity occupied by the layer 7. That is, a thermocycling process occurs, which negatively affects the geometry of the box. The refractory layer 7 prevents the negative impact of the thermocycling process on the box 7, which, in turn, preserves the structural integrity and stability of the functional properties of the device for introducing inert gas into the melt during the treatment of the metal melt with gases.

Thus, the design feature of the device for processing molten metal with gases, which consists in the additional installation of a gas-tight box in the recess of the reinforcing layer, the location on it of a layer of refractory with a thickness of 15-35 mm less than the reinforcing layer, the installation of intermediate beacons between the gas-tight box and the working lining, and more than the second layer, between the beacons there is a gas distribution layer, on which the working lining of the bottom of the container rests, which will allow to avoid unforeseen gas losses during purging and to conduct the process in a strictly specified mode, which in turn will allow to automate the process of metal processing with gases. The use of the proposed capacity will allow to significantly increase the efficiency of the metal gas treatment technology, technical and economic indicators, reduce the time of proving the metal in terms of chemical composition and temperature, eliminate cases of inconsistency in processing modes, and reduce production costs. t p" z : and N s Y singular KZ

PEKY mon o

NVK is not how

FROM NOW ON KISHNA VN i

KO TO S

- tt de ren ny nyn nina xx y С Х 1 х х их

DYN m i i z x IN i sk them 4 in 2 N

Claims (3)

1. A device for introducing an inert gas into a metal melt, containing a metal jacket, wall lining, bottom lining, consisting of reinforcement, working layers and a gas distribution layer located in the recess of the reinforcement layer of the bottom, which differs in that between the bottom of the recess and the gas distribution layer is additionally equipped with a gas-tight box, in which the layer is made of refractory material, the thickness is less than the reinforcement layer by 15-35 mm, 1 beacons, and above the layer between the beacons there is a gas distribution layer, on which the working lining with gas-permeable seams of the bottom of the container rests. 2. The device according to claim 1, which is characterized by the fact that the refractory layer located on the bottom of the gas-tight box has high thermal insulation properties. 3. The device according to point I, which differs in that the gas-tight box is made above the recess in the reinforcing layer by the thickness of the horizontal seam between the reinforcing and working layers.