RU2735014C1 - Method of metallurgical aggregates lining - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to a method of lining metallurgical aggregates. Proposed method comprises the following steps: cleaning surface intended for lining with shotcrete concrete from contaminants; mixing shotcrete concrete with water by means of equipment for preparation of concrete mixture; method includes directing the concrete mixture obtained at the previous step into a concrete pump, and further along the main line to the work site and applying the mixture to the lining; at that, at the end of the main line there is a nozzle for application of the concrete mixture; concrete mixture is applied on prepared surface for lining with shotcrete concrete by mixing concrete mixture with curing agent on nozzle.

EFFECT: technical result is reduction of consumption of refractory materials used for lining of working layer of walls of metallurgical units.

15 cl, 5 dwg

Description

FIELD OF TECHNOLOGY

[001] This technical solution generally relates to the field of metallurgy, namely to the technologies of lining metallurgical and other thermal units by the method of shotcreting and its hardware design.

LEVEL OF TECHNOLOGY

[002] From the prior art, there is a known method of lining by gunning the surfaces of various units and the design of a device for its implementation are given in the reference literature [Brief Polytechnic Dictionary. - M .: State publishing house of technical and theoretical literature. (Editorial council: Yu.A. Stepanov, F.S. Demyanyuk, A.A.Znamenskiy and others) 1956, p. 954, term - "shotcrete"]. The method includes the application of a special cement mortar (for metallurgical units, a refractory mixture) under the action of compressed air, carried out by means of a cement gun (lining device). The dry mixture is loaded into a cement gun, from which, under air pressure, it enters a hose ending with a nozzle tip. The mixture is automatically wetted before entering the nozzle. The resulting shotcrete (pneumatic concrete) has great strength, density, water and air tightness.

[003] The disadvantage of shotcrete technology is that the rate of application of the material is 1.0-1.5 tons per hour (at a mass density of 3.0-3.20 t / m3), while the shotcreting technology allows applying 6-16 tons of material per hour at the same density. In addition, the disadvantage of the shotcrete technology is the lower, in comparison with the shotcreting technology, indicators of the applied material, namely, its mechanical strength, porosity and packing density, which ultimately affects the durability of metallurgical and other thermal units.

ESSENCE OF THE TECHNICAL SOLUTION

[004] This technical solution is aimed at eliminating the disadvantages known from the prior art.

[005] The main technical problem or technical problem solved in this technical solution is to change the basic operating model of a metallurgical unit, for example, a steel-pouring ladle.

[006] The technical result achieved by solving the above technical problem is to reduce the consumption of refractory materials used for lining the working layer of the walls of metallurgical units.

[007] The specified technical result is achieved through the use of shotcrete technologies and appropriate equipment, unshaped refractory concretes based on tabular alumina and special additives.

[008] An additional technical result is an increase in the duration of the working campaign of the metallurgical unit and a decrease in the total consumption of refractories.

[009] In addition, emergency situations with metal leakage through the lining are reduced, the turnaround time of metallurgical units in operation is increased, which makes it possible to increase the amount of steel smelted.

[0010] The specified technical result is achieved by implementing a method for lining metallurgical units, in which the surface intended for lining with shotcrete from contaminating elements is cleaned; mix shotcrete with water by means of equipment for preparing concrete; the concrete mixture obtained at the previous step is sent to the concrete pump, and then along the highway to the place of work and applying the mixture to the lining, and at the end of the highway there is a nozzle for applying the concrete mixture; the concrete mixture is applied to the prepared surface for lining with shotcrete concrete by mixing the concrete mixture with a hardener at a nozzle.

[0011] In some embodiments of the technical solution, when mixing refractory components, shotcrete is low-cement shotcrete or ultra low-cement concrete based on tabular alumina and / or corundum with the addition of fused Al2MgO4 spinel, or shotcrete based on fused or sintered periclase with the addition of fused Al2MgO4-spinel or 6-valent chromium oxide.

[0012] In some embodiments of the technical solution, the equipment for preparing concrete mixture is a pneumatic vessel with a built-in forced mixer and / or paddle mixer for processing refractory masses and a pump for conveying concrete.

[0013] In some embodiments of the technical solution, the water temperature is in the range from 5 ° C to 30 ° C.

[0014] In some embodiments of the technical solution, the curing agent is sodium silicate.

[0015] In some embodiments of the technical solution, the water consumption is in the range of 4-10% of the total concrete mixture.

[0016] In some implementations of the technical solution, the time for mixing the concrete mixture after adding water is from 2 to 10 minutes.

[0017] In some embodiments of the technical solution, shotcrete after mixing is wetter than vibrated concrete.

[0018] In some embodiments of the technical solution, refractory material is cleaned with jackhammers and / or a chain cutter.

[0019] In some embodiments of the technical solution, when the concrete mixture is applied to the desired surface, it is heated using a heat gun or by placing the concrete mixture in a warm room.

[0020] In some embodiments of the technical solution, the concrete mixture is continuously applied to the desired surface of the lining.

[0021] In some embodiments of the technical solution, the concrete mixture is applied to the required surface of the lining in one layer 10-100 mm thick.

[0022] In some embodiments of the technical solution, when applying the concrete mixture to the required surface of the lining, the thickness of the application is determined by the wall wear in the areas of the steel drain holes and / or purge plugs and / or the edging side and the state of the rows of bricks adjacent to the slag belt.

[0023] In some embodiments of the technical solution, the concrete is applied to the desired surface of the lining, with the nozzle held perpendicular to the surface of the application of the lining.

[0024] In some embodiments of the technical solution, a concrete mixture is applied to the desired surface of the lining, with the nozzle held at a distance of 0.5-1.2 meters.

BRIEF DESCRIPTION OF DRAWINGS

[0025] The features and advantages of the present technical solution will become apparent from the following detailed description and the accompanying drawings, in which:

[0026] FIG. 1 shows an exemplary embodiment of a metallurgical plant.

[0027] FIG. 2 shows an exemplary embodiment of a GS800 rotary type cleaning unit.

[0028] FIG. 3 shows an example of the implementation of the dismantling of slag and steel residues from a brick lining.

[0029] FIG. 4 shows an example of the implementation of the installation of the refractory lining from the table (second chord).

[0030] FIG. 5 shows a variant of the implementation of the schedule of holding, drying and heating a steel ladle 380 tons.

DETAILED DESCRIPTION OF THE INVENTION

[0031] Below will be discussed in detail the terms and their definitions used in the description of this technical solution.

[0032] Lining - lining with refractory, chemically resistant, as well as heat-insulating materials that cover the inner surface of metallurgical furnaces, ladles, boiler furnaces and other equipment.

[0033] Shotcrete is a progressive method of applying one or more layers of mortar made of cement, sand, functional additives and water to the surface of a structure under compressed air pressure.

[0034] Refractory materials (hereinafter referred to as refractories) are a non-metallic material with refractoriness not lower than 1580 ° C, used in units and devices to protect against the effects of thermal energy and gaseous, liquid, solid corrosive reagents.

[0035] Metallurgical unit - a set of structurally related technological equipment and devices, providing a complex metallurgical process in terms of mass and continuous production. The metallurgical unit has higher performance indicators, energy intensity and product quality, and allows more efficient solutions to the issues of production automation and environmental protection.

[0036] Below will be described in detail the method of lining metallurgical units, performed in steps. As an example of the implementation of a metallurgical unit in this solution, a steel-pouring ladle is described, however, it is obvious to any specialist that the implementation is not limited to it.

[0037] Step 101: clean the surface to be lined with shotcrete from contaminants.

[0038] Surface preparation requires the use of correct concrete demolition techniques and properly cleaned surfaces.

[0039] Before applying shotcrete, the surface of the brick or concrete layer when using a monolithic lining of metallurgical units must be cleaned of dust, slag residues, steel and degenerated refractory, as shown in FIG. 3.

Cleaning can be done with jackhammers or specialized equipment (eg, a chain cutter), such as a GS800 rotary type cleaning unit, as shown in FIG. 2. Chains are attached to the rotating head, which, while rotating, clean the surface of the brick lining. In some embodiments, preparing the metal surface includes removing loose rust, flaking scale, and other contaminants. Preparation of the refurbished lining includes: removal of weak, peeling and destroyed areas throughout the entire thickness of the shotcrete layer to the metal surface or to the insulating sublayer with at least two anchors exposed, blowing the surface with compressed air and, if necessary, installing additional anchors provided for by the project and nets. When blasting the surface, it is recommended to inject a small amount of water to reduce dust.

[0040] Step 102: The shotcrete is mixed with water by means of a concrete batching equipment.

[0041] In this technical solution to ensure the resistance of the walls of metallurgical units (without breaking the residual brick layer and, accordingly, without installing a new set of refractories for the working layer of the walls after 80 heats) at the level of (approximately) 40 + 40 (80) + 40 = 120 melting (duration of the campaign for the resistance of the wall in the metal zone) shotcrete and sodium silicate can be used as a hardener. In this technical solution, as refractories can be used, for example, periclase-carbon brick or alumopericlase-carbon brick. In this case, this technical solution can be used in relation to other refractories. As shotcrete, for example, low-cement shotcrete or ultra low-cement concrete based on tabular alumina and / or corundum with the addition of fused Al2MgO4 spinel can be used (it is also possible to use shotcrete concretes based on fused or sintered periclase with the addition of fused Al2MgO4 spinel), on a hydraulic bond brand Seven Shot 92 NR 08 Z. In other embodiments, but not limited to them, chromium oxide 6 valence can be used as an additive. Sodium silicate is an additional, but at the same time integral material for the technological process. The consumption of liquid glass (sodium silicate) can be in the range of 12-18 kg / t of concrete used.

[0042] In an exemplary embodiment, the amount of materials for one steel ladle (to extend the campaign from 80 to 120 melts) may be as follows:

[0043] The amount of material Seven Shot 92 NR 08 Z for the repair of the walls of the steel-pouring ladle in the metal zone can be laid based on the thickness of the applied layer of material from 10 to 100 mm (the thickness of the layer can be reduced, and the material can accordingly be distributed to other zones and / or continuation of the campaign).

[0044] As an example of implementation, an order is received for the implementation of lining for 20 tons of shotcrete and 400 kg of sodium silicate is added to it (the calculation is in a ratio of 1:20 kg, since the plant during the production of work is losing material when setting up equipment, equipment washing and other negative factors). Shotcrete masses are cement-bonded concrete and are therefore sensitive to moisture and therefore must be stored in a dry, closed room. The liquid binder should be stored at a temperature not lower than + 5 ° C.

[0045] All equipment and tools for the preparation of concrete mixtures must be cleaned of previous wet and dry materials. The cleaning equipment can be a pneumatic vessel with a built-in forced mixer, for processing refractory masses, for example, the ESTROMAT 850 and / or REED models and a concrete pump, for example, the SCHWING SP 500 model. Cleaning is carried out using a high-pressure water pump and hand tools ...

[0046] For mixing the concrete mixture can be used water used at the enterprise for mixing concrete (the use of chemically purified water is prohibited, since chemically purified water contains impurities that negatively affect the durability of the refractory, as they create fusible compounds during the operation of the layer shotcrete - concrete.). The recommended water temperature is from 5 ° C to 30 ° C, due to the fact that at low water temperatures the setting time of concrete increases, and at high temperatures it is greatly reduced. The water consumption must be within the limits indicated in the corresponding technical sheet (for example, it can be indicated in the range of 4-10%). Shotcrete, after mixing, should look wetter than normal vibratory concrete. This is determined automatically by the operator of the plant where the concrete is mixed or by means of machine vision algorithms. Mixing time after adding water is 2 to 7 minutes. If the mixing process is carried out in a shorter time, then there is insufficient moisture in the concrete and it turns out to be dry.

[0047] Step 103: direct the concrete mixture obtained in the previous step into the concrete pump, and then along the main line to the work site and apply the mixture to the lining, and at the end of the main line there is a nozzle for applying the concrete mixture.

[0048] After the mixture is ready for application, the refractory concrete is discharged into the concrete pump, and then through the hoses to the work site and the application of the material to the lining.

[0049] After feeding the finished mixture into the receiving hopper of the pump, the material is fed into the transport system at the lowest possible speed until the mixture appears at the junction of the hose with the nozzle. To connect the nozzle to the material hose, compressed air hoses and binder material, the material flow through the transport system is stopped.

[0050] Two nozzles directly carrying out the work are in the ladle. The assembled nozzle is accepted and only at their command, the material is fed for the installation of the refractory lining. The concrete mixer technician continues to prepare the mix.

[0051] Step 104: Apply concrete to the prepared shotcrete lining surface by mixing the concrete with a hardener at a nozzle.

[0052] All work on the installation of refractory lining begins with preparatory activities:

1. Transportation of equipment to the place of work.

2. Determination of the place of installation of equipment and tools.

3. Opening of the order - the admission to work.

4. Determination of points of connection of energy carriers.

5. Installation of main and auxiliary equipment.

6. Checking the equipment in idle mode.

[0053] When installing the pipeline, the last link (rubber hose) must be installed with a diameter of 38 mm. This diameter allows you to create a higher density of the applied refractory lining, reduces the amount of rebound, in contrast to the diameter of 50 mm.

[0054] It is necessary to proceed with the installation of the refractory lining upon completion of all preparatory measures.

[0055] Before applying the mixture to the prepared surface, the pipeline is lubricated.

[0056] A mixture is prepared for lubricating pipes and hoses. For lubrication, wallpaper glue or fireclay mortar is used (1 pack of glue for 10 liters of water), and it is necessary to prepare 20 liters of lubricant. This lubricant reduces the coefficient of friction of concrete when moving through pipes and hoses. You can also use technical lubricants, such as lithol or grease. This operation is applied at every start of shotcreting work (if the concrete supply pipeline was flushed). Technicians on the job site pour the mixture into the concrete supply hose. The adapter is connected and compressed air distributes the lubricant evenly throughout the entire pipeline.

[0057] The concrete is mixed with the hardener SODIUM SILICATE using a nozzle using compressed air (in winter, the hardener is heated to 15-25 ° C, using a heat gun) and applied to the required surface. A line departs from the concrete pump, through which material is supplied to the work site, and at the end of this line, a nozzle is installed, into which liquid glass (sodium silicate) and compressed air are supplied. Heating is carried out using heat guns or, in some embodiments, by placing the concrete mixture in a warm room.

[0058] Depending on the degree of wear of the working lining on the refractory material, which may be a brick, the application of shotcrete is performed continuously in one layer 10-100 mm thick. The level of wear is usually determined at the lining site, depending on the ladle lining scheme used at the enterprise and the hot repair scheme. Typically, the thickness of the application is determined by the wear of the wall in the areas of the steel drainage holes, purge plugs, the edging side and the condition of the rows of bricks adjacent to the slag belt. Shotcreting should not be interrupted due to the fact that concrete can begin to set in the highways and the concrete pump, which will lead to the equipment stopping for flushing and washing. The nozzle should always be held perpendicular to the application surface at a distance of 0.5-1.2 meters. It is at this distance of application of the mixture that a denser application of concrete occurs, which makes it possible to achieve the declared indicators of strength and porosity. This distance contributes to obtaining a denser structure of the refractory material after application, which will allow the metallurgical unit to operate longer. " The perpendicular position of the nozzle relative to the surface to be applied is due to the amount of rebound and the quality of the applied layer. The material is applied immediately with the required thickness from bottom to top of the application area, which allows you to control the thickness of the installed concrete and the quality of the installation. Rebound is never combined with material or reused. After applying shotcrete to the walls, the formed rebound is removed from the working bottom of the steel-pouring ladle and the bottom lining is repaired. [0059] The use of the specified technical solution provides the specific consumption of refractories on the working layer of the walls at the level of 131 melts:

0 плавок - холодный ремонт

0 swimming trunks - cold repair

40 плавок - горячий ремонт (ремонт шлакового пояса), шоткретирование стен (2-4 т.);

40 heats - hot repair (repair of a slag belt), shotcreting of walls (2-4 tons);

80 плавок - шоткретирование стен (2 т.);

80 swimming trunks - wall shotcreting (2 tons);

120 плавка - окончание кампании.

120 smelting - end of the campaign.

[0060] Technically, the work of installing the refractory lining of the ladle may consist of two chords vertically. The first lining belt is applied from the bottom of the steel casting ladle to a height of about 1.5 meters. The second lining belt is applied from a table that is lowered into the ladle after completing the installation of the first lining lining as shown in FIG. 4. The height of the second lining belt is limited by the height of the brick lining of the steel zone.

[0061] During the installation of the lining, the formwork is not used in order to create the solidity of the lining. The application of the material is carried out in a circle, first there is "spraying" with a thickness of about 10-15 mm, after the second application, the required thickness of the lining is formed. Also, during the work, a system of beacons can be used, that is, vertical strips of material 200-300 mm wide are made to the height of the belt, with a step of 1.5-2 meters of the required thickness (the thickness is controlled by the second nozzle located also in the bucket), after which the material is applied between the beacons.

[0062] The thickness of the lining application depends on the residual thickness of the brick lining. In this technical solution, a technology has been developed that the application of a lining of more than 100 mm is not advisable, peeling occurs, and many cracks are formed during drying.

[0063] The average thickness of the applied lining should not be more than 30-60 mm. The only exceptions are the place where the slag is discharged and the slag zone, here the lining thickness reaches 100 mm. Therefore, the nozzle and control technician visually determine the thickness of the applied lining.

[0064] When installing refractory lining with negative environmental values, it is necessary to take measures in advance to store the material and binder in a room with a positive temperature, at least 5 days before the installation of the lining.

[0065] At the end of the work, work is carried out to clean up equipment and pipelines, disconnect from energy sources, complete and transport to the storage site.

[0066] Drying is an integral part of the performance of the refractory lining.

[0067] Before drying, it is necessary to withstand the applied lining for 4 hours; during the holding, it is necessary to ensure the air temperature in the steel-pouring ladle and its metal structure at least + 5 ° С. It is possible to use a heat gun or a gas torch without contact of an open flame with the surface of a monolithic layer.

[0068] When developing drying schedules, proceed from the possibility of drying-heating stands. It is necessary to organize the holding of concrete at temperatures of 150 ° C and 450 ° C, in the future, the rate of heating of concrete is unlimited and is determined by the possibility of a heating stand. In practice, a holding, drying and reheating schedule roughly shown in FIG. five.

[0069] Specific tests of the method of lining and repair of a steel ladle by Seven Refractories LLC confirm the industrial applicability of the invention.

[0070] Modifications and improvements to the above described embodiments of this technology may be apparent to those skilled in the art. The above description is given as examples and not to set limits. The scope of this technology, therefore, can only be limited by the scope of the attached claims.

Claims (19)

1. Method for lining metallurgical units, including the following steps:

clean the surface intended for lining with shotcrete from contaminating elements;

mix shotcrete with water by means of equipment for the preparation of concrete;

the concrete mixture obtained in the previous step is sent to the concrete pump, and then along the highway to the place of work and applying the mixture to the lining, and at the end of the highway there is a nozzle for applying the concrete mixture;

the concrete mixture is applied to the prepared surface for lining with shotcrete concrete by mixing the concrete mixture with a hardener at a nozzle. 2. A method of lining metallurgical units according to claim 1, characterized in that when mixing refractory components of shotcrete is low-cement shotcrete or ultra-low-cement concrete based on tabular alumina and / or corundum with the addition of fused Al ₂ MgO ₄ -spinels, or shotcrete - concrete based on fused or sintered periclase with the addition of fused Al ₂ MgO ₄ spinel or 6-valent chromium oxide. 3. A method for lining metallurgical units according to claim 1, characterized in that the equipment for preparing concrete is a pneumatic vessel with a built-in forced mixer and / or a paddle mixer for processing refractory masses, and a pump for conveying concrete. 4. A method for lining metallurgical units according to claim 4, characterized in that the water temperature is in the range from 5 ° C to 30 ° C. 5. The method of lining metallurgical units according to claim 1, characterized in that the hardener is sodium silicate. 6. The method of lining metallurgical units according to claim 4, characterized in that the water consumption is in the range of 4-10% of the total concrete mixture. 7. The method of lining metallurgical units according to claim 4, characterized in that the time for mixing the concrete mixture after adding water is from 2 to 7 minutes. 8. The method of lining metallurgical units according to claim 1, characterized in that shotcrete after mixing is wetter than vibro-poured concrete. 9. The method of lining metallurgical units according to claim 1, characterized in that the refractory material is cleaned with jackhammers and / or a chain mill. 10. The method of lining metallurgical units according to claim 1, characterized in that when the concrete mixture is applied to the required surface, it is heated using a heat gun or by placing the concrete mixture in a warm room. 11. The method of lining metallurgical units according to claim 1, characterized in that the concrete mixture is applied to the required surface of the lining continuously. 12. The method of lining metallurgical units according to claim 1, characterized in that the concrete mixture is applied to the required surface of the lining in one layer 10-100 mm thick. 13. The method of lining metallurgical units according to claim 1, characterized in that when the concrete mixture is applied to the required surface of the lining, the thickness of the application is determined by the wall wear in the zones of the steel drain holes and / or purge plugs and / or the tilting side and the state of the rows of bricks adjacent to slag belt. 14. The method of lining metallurgical units according to claim 1, characterized in that the concrete mixture is applied to the required surface of the lining, and the nozzle is held perpendicular to the surface of the application of the lining. 15. The method of lining metallurgical units according to claim 1, characterized in that the concrete mixture is applied to the required surface of the lining, and the nozzle is kept at a distance of 0.5-1.2 meters.

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