RU2522283C1 - Tandem reflecting furnace with casting shoe for remelting of aluminium scrap - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: furnace includes a housing formed with refractory external side, front and rear end walls, two baths restricted with bottoms, an arch and walls, two drain tap holes, a gas duct and a pedestal, on which all parts are arranged. In the furnace there is external heat insulation of walls, which consists of asbestos tailings and a double layer of asbestos boards. The furnace pedestal has two layers made of light-weight brick with the double layer of asbestos boards between them, a quartz sand layer from below and from above, which is mixed with asbestos tailings, and three layers of asbestos boards on the top, on which bottom block are laid. A casting shoe includes a housing formed with refractory external side, front and rear end walls, a bath, restricted with a bottom, an arch and walls, and drain tap holes. The casting shoe pedestal has two layers made of light-weight brick and separated with an asbestos board layer, and a lower asbestos board layer. The casting shoe has two tap holes made in quick-changeable tap-hole bricks in a box. The furnace has two turning chutes with a turning bowl, which are installed on brackets welded to the casting shoe box, which are turned during liquid metal pouring process for subsequent pouring of molten metal in the furnace to pouring equipment located in a maintenance sector with an angle of 143°. Five injection burners are installed in the furnace and the casting shoe. The furnace operates at natural and artificial draft with a dust and gas cleaning system.

EFFECT: improving efficiency and decreasing heat losses.

5 cl, 12 dwg

Description

The invention relates to ferrous metallurgy, and in particular to smelting units for remelting secondary aluminum scrap and waste aluminum alloys into ingots and ingots. The furnace can be used for refining, producing alloys, averaging the chemical composition of scrap.

A known analogue is a reflective furnace for melting metal (Information source A.A. Baranov, O.P. Mikulyak, A.A. Reznyakov "Technology of secondary non-ferrous metals and alloys", pp. 22-23), containing a housing formed by brickwork external walls, as in the declared furnace, two bathtubs bounded by hearths and walls, two arches, a drain outlet and a flue.

The disadvantages of this furnace are:

1. The second melting chamber acts as a mixer (piggy bank), which ultimately reduces the productivity of the furnace.

2. The furnace has insufficient thermal insulation of the walls, the arch, reducing heat loss to the external environment.

3. The furnace does not have a dust and gas cleaning system and during operation will pollute the environment with harmful emissions.

4. In the hearth lining furnace, conventional refractory bricks are used, rather than hearth blocks, which significantly increase the life of the furnace. 5. From the description of the furnace it follows that it does not provide a forced melting mode. Due to the above disadvantages, the furnace cannot provide a solution to the technical problem. A well-known analogue is a two-chamber reflective furnace for remelting aluminum scrap (Information source M.S. Shklyar "Furnaces of secondary non-ferrous metallurgy", publishing house "Metallurgy", 1987, pp. 35-37), containing a housing formed by brickwork of external walls, as in the declared furnace, two bathtubs bounded by hearths and walls, two vaults, a drain outlet and a flue.

The furnace is designed for remelting secondary aluminum and has the following disadvantages:

1. The second melting chamber acts as a mixer (piggy bank), which ultimately reduces the productivity of the furnace.

2. The furnace has insufficient thermal insulation of the walls, the arch, reducing heat loss to the external environment.

3. The furnace does not have a dust and gas cleaning system and during operation will pollute the environment with harmful emissions.

4. In the hearth lining furnace, conventional refractory bricks are used, rather than hearth blocks, which significantly increase the life of the furnace.

5. From the description of the furnace it follows that it does not provide a forced melting mode. Due to the above disadvantages, the furnace cannot provide a solution to the technical problem.

A similar analogue is known - a two-shaft reflective furnace (Information source M.S. Shklyar "Furnaces of secondary non-ferrous metallurgy", publishing house "Metallurgy", 1987, pp. 87-89), which is the closest (prototype), containing a housing formed by external brickwork walls, as in the declared furnace, two bathtubs, limited by hearths, a vault and walls, drain gaps and flues.

I believe that the oven, taken as a prototype, has the following disadvantages:

1. The furnace does not have a piggy bank.

2. The furnace has insufficient thermal insulation of the walls, the arch, reducing heat loss to the external environment.

3. The furnace does not have a dust and gas cleaning system and during operation will pollute the environment with harmful emissions.

4. In the hearth lining furnace, conventional refractory bricks are used, rather than hearth blocks, which significantly increase the life of the furnace.

5. From the description of the furnace it follows that it does not provide a forced melting mode.

6. The furnace uses two stationary troughs to drain molten metal.

Due to the above disadvantages, the furnace cannot provide a solution to the technical problem.

The objective of the invention is the creation of a high-performance gas twin-shaft reflective type furnace with a piggy bank for remelting aluminum scrap, which allows to reduce emissions of harmful gases into the atmosphere, reduce heat loss to the environment, as well as increase its life and introduce a rotary trough into the furnace.

EFFECT: developed gas two-shaft reflective type furnace with a piggy bank for remelting aluminum scrap is highly productive, having two rotary troughs, a long service life, which allows: to reduce heat loss to the environment due to special thermal insulation, to conduct the remelting process on natural and artificial traction with a system dust and gas cleaning, which makes it environmentally friendly.

The specified technical result is achieved due to the fact that in a two-shaft furnace for remelting aluminum scrap, containing a body formed by refractory outer side, front and rear end walls, two bathtubs bounded by hearths, a vault and walls, drain gaps and ducts, according to the invention, a furnace pedestal was introduced, which has two layers of lightweight brick with a double layer of asbestos between them, and also has a layer below and a layer on top of quartz sand mixed with crushed asbestos besides the one with the top three layers of asbestos board on which the hearth blocks of the MLSP of two hearths are laid.

Thermal insulation of the furnace pedestal, consisting of two layers of lightweight brick, four layers of asbestos board and two layers of quartz sand mixed with crushed asbestos chips, allows you to further maintain the temperature of the metal in the bathtubs of the furnace. Hearth blocks mullite high-density MLSP, laid on three layers of asbestos board, have high refractoriness and resistance and allow to increase the service life of the furnace. The use of blocks MLSP instead of conventional piece products can reduce the number of joints, which reduces gas permeability and increases the slag resistance of the lining; get cost savings, because the process of pre-fabrication of piece refractories disappears, speed up the process of building a furnace and reduce the proportion of manual labor.

It should be noted that a piggy bank formed by refractory external side, front and rear end walls, a bathtub limited by a hearth, a vault and walls, drainage gates and a flue are introduced into the proposed two-shaft furnace for remelting aluminum scrap. The piggy bank pedestal has two layers, laid out of lightweight brick, separated by a layer of asbestos board, as well as the bottom layer of asbestos board. The bottom blocks of the MLSP No. 1 piggy bank are laid on three layers of asbestos board. Thermal insulation, consisting of two layers of lightweight brick, four layers of asbestos board, as well as the bottom layer of asbestos board, allows you to save the temperature of the metal in the bath of the piggy bank. The bottom blocks of the MLSP, laid on three layers of asbestos board, have high refractoriness and resistance and allow to increase the life of the piggy bank.

At the same time, a two-shaft reflective furnace for remelting aluminum scrap has a nineteen-mixing medium-pressure injection burner in each side wall directed at the charge, five mixers of which are equipped with nozzles and placed in the center with a flame length of 2.4 m, and fourteen are located on the periphery with providing, when burning a gas-air mixture of flame, 1.2 m long, and two twelve-mixing medium-pressure burners, four mixers of which are equipped with nozzles and placed in the center with ensuring flame length 2.1 m, and eight are located on the periphery with the provision of combustion gas-air flame flame 1.1 m long, installed in the end wall of the furnace, aimed at the bath and the charge. In the piggy bank, a nineteen-mixing medium-pressure injection burner is installed obliquely to the bottom of the piggy bank, directed to a bath with molten metal. This arrangement of the burners allows to achieve a high melting speed, reduce fumes (according to practical data). The thermal power of the burners is 7776 kW, which makes the furnace highly productive, allowing for forced melting.

At the same time, the two-shaft reflective furnace with a piggy bank for remelting aluminum scrap has two rotary troughs mounted on brackets welded to the box of the piggy bank, which rotate during the pouring of liquid metal and have a rotary bowl in the design, which allows the metal deposited in the furnace to be sequentially poured into the casting equipment located in the service sector with an angle of 143 °.

Moreover, steel boxes are installed on the foundations of the furnace and the piggy bank, having thermal insulation between them and each wall, consisting of asbestos chips, a double layer of sheet asbestos board. This design solution significantly reduces heat loss to the environment.

In addition, the arches of the furnace and the piggy bank have a double layer of asbestos board, which is covered with asbestos chips, diluted in liquid glass. This further reduces heat loss from the furnace.

It should be noted that it has two tap holes made in quick-change tap-hole bricks in the box, to ensure the possibility of their replacement without stopping the furnace, and the block of MLSP is the material of the pulp brick.

Finally, the furnace is equipped with a dust and gas cleaning system, which includes a mixing chamber, a smoke exhauster, a dust cleaning unit and a gas cleaning unit, which makes the process of remelting aluminum scrap environmentally friendly.

Introduction to the furnace design of the above devices, materials, etc. provides a solution to the problem.

Figure 1 is a longitudinal section of the furnace aa.

Figure 2 - Section BB of the furnace.

Figure 3 - Cross section bb furnace.

Figure 4 - Cross section GG furnace.

Figure 5 - View twelve mixing injection burner from the side of the gas distribution chamber.

Figure 6 - Section DD DD twelve mixing injection burner.

7 is a view of a nineteen-mixing injection burner from the side of the gas distribution chamber.

On Fig - Section EE nineteen-mixing injection burner.

Figure 9 - Layout of the furnace in the melting site.

Figure 10 - Unit dust cleaning.

Figure 11 - Cyclone.

On Fig - Installation of gas purification.

The proposed furnace contains a pedestal mounted on the foundation 1 of the furnace, having two layers laid out of lightweight brick 2, with a double layer of asbestos board 3 between them, and also having a layer below and a layer on top of quartz sand 4 mixed with crushed asbestos chips, in addition, having on top three layers of asphalt board 5, on which the hearth blocks 6 of the two hearths of figure 1 are laid. Two layers of lightweight brick 2, with a double layer of asbestos board 3 between them, the lower layer of quartz sand 4 are in a casing of sheet steel 5 mm thick. The thermal insulation of the pedestal, consisting of two layers of lightweight brick 2, four layers of asbestos board and two layers of quartz sand 4. mixed with crushed asbestos chips, allows you to further maintain the temperature of the metal in the bathtubs of the furnace. Hearth blocks 6 of the MLSP No. 1, laid on three layers of asbokarton 5, have high refractoriness and resistance and allow to increase the service life of the furnace. The use of hearth blocks 6 MLSP No. 1 (thickness 300 mm, width 400 mm, length 1000 mm) instead of conventional piece products, it is possible to reduce the number of joints, which reduces gas permeability and increases the slag resistance of the lining; allows you to save money, because there is no longer the process of prefabrication of piece refractories, complete units of almost any configuration, speed up the construction process and reduce the proportion of manual labor. The joints between the hearth blocks 6 of the MLSP No. 1 are filled with finely ground dry chamotte powder, and the author achieved even better results when the chamotte powder covered in the slots of the hearth blocks 6 of the hearth was filled with liquid glass in the upper part and then “flush” with the upper plane of the hearth. refractory adhesive mastic. The two-shaft furnace for remelting aluminum scrap has a body formed by refractory outer side 7, front 8 and rear 9 end walls, two baths 10, limited by hearths, arch 11 and walls. The hearth blocks 6 of each bath 10 are laid out with a slope towards the middle of the bath 10 and to the wall 12 of figure 2 laid in the middle of the furnace. The wall 12 is supported in the lower part by a small arch 13, in the upper part it has two channels 14 connecting the spaces above the baths 10 of the furnaces to the gas duct 15 of FIG. 3. In the lower part of the wall 12 there are two channels 16, through which the molten metal flows into the central channel 17 and further into the piggy bank. Above each bathtub 10, a vault 11 is assembled, one end of which rests on the heel bricks 15 of the side wall 7, and the other on the wall 12. It is important to note that the arches 11 of the furnace have a double layer of asbestos board 18, which is covered with asbestos chips, diluted in liquid glass. This reduces heat loss from the furnace. All walls are made of refractory fireclay bricks ША1. As a binder, a refractory solution is used, consisting of refractory clay (21%), fireclay powder (75%), water glass (3%) and phosphon (aluminochromophosphate mixture, 1%).

Two loading windows are made in the front wall 8, into which the charge is loaded, which are closed by the shutters 19. In the back wall 9 of the furnace two openings 20 are laid obliquely to the hearth for installation of two medium-pressure twelve-mixing burners directed to the bath and charge, four of which are mixers equipped with nozzles and placed in the center with a flame 2.1 m long, and eight are located on the periphery with a flame providing 1.1 m long when burning a gas-air mixture; FIG. 4, FIG. 5, FIG. 6. Each twelve-mixing medium-pressure burner contains a flame-stabilizing tunnel 21, refractory packing mass 22, 12 of cylindrical mixers 23, united by a common welded gas distribution chamber 24, in each mixer 23 four nozzles 25 are drilled at an angle of 25 ° to their axes. The burner comprises a casing 26 welded to a cylindrical gas distribution chamber 24, into which a refractory packing material 22 is packed, a cast flame-stabilizing tunnel 21, which is worn from below onto a cylindrical gas distribution chamber 24 and a casing 26, and is welded around the perimeter to a cylindrical gas distribution chamber 24. In a cylindrical on the gas distribution chamber 24, eight mixers 23 without nozzles are located on its periphery, and 4 mixers 27 with nozzles having cast ribs on the inner surface, and a guide device consisting of a cone 28, an axis 29, two nuts 30 for fastening the cone 28 is welded in the center of the gas distribution chamber 24. Axis 29 is welded into the cylindrical gas distribution chamber 24.

Mixers, nozzles for mixers, a cast flame-stabilizing tunnel, all parts of the guide device are made of heat-resistant cast iron ЧХ34. At the same time, heat-resistant cast iron used as a material for the manufacture of mixers, nozzles for mixers, a cast flame-stabilizing tunnel, and all parts of the guide device allows to increase the life of the burner.

Each mixer 23 without a nozzle is a casting and is a pipe with a diameter of 59 × 10 mm and a length of 280 mm, in which four nozzles 25 are drilled along the periphery at an angle of 25 ° ± 1 ° to their axes with a countersink of the inlet part of 0.5 mm at an angle of 90 ° . Each mixer 27 with nozzle has a nozzle 31 with a length of 50 mm, on the inner surface of which there are 10 cast fins. The nozzles 31 to the mixers in case of their burning (melting during long-term operation) are replaced with new ones, which, ultimately, increases the life of the burner. Natural gas is supplied through a pipe 32 to a cylindrical gas distribution chamber 24. A two-shaft reflective furnace for remelting aluminum scrap has a nineteen-mixing medium-pressure injection burner in each side wall 7 aimed at the charge, five mixers 27 of which are equipped with nozzles 31 and are located in the center with a flame length of 2.4 m, and fourteen mixers 23 are located on the periphery providing a flame of 1.2 m long during combustion of the gas-air mixture. The design of the nineteen-mixing medium-pressure injection burner is similar to the design of the twelve-mixing burner medium pressure with the only difference that in the cylindrical gas distribution chamber 24 are located on its periphery fourteen mixers 23 without nozzles, and in the central part there are 5 mixers 27 with nozzles 31 having cast ribs on the inner surface, there is no guide device in the center of the gas distribution chamber. In addition, the thermal power of the burner is 34% more than a twelve-mixing medium-pressure burner. The nominal operating pressure of the burners is 0.08 MPa. When the furnace is lined, injection burners are placed in the openings of the furnace. Then, the burners are lined with a special refractory ramming mass of their own design, having the following composition:

Quartz sand;

Technical lignosulfonate TU 13-0281036-89;

Powder ground clay PHB TU 1522-009-00190495-99;

Foscon (aluminochromophosphate mixture) TU 2149-150-10964029-01;

Water.

On the pedestal of the furnace there is a steel box 33 in which the walls of the furnace are laid. Steel box 33, in order to avoid blowing, warping, reinforced with vertical 34 and horizontal 35 channels No. 20 of figure 1. A steel box 33 is welded to a casing 36 of sheet steel 5 mm thick and has thermal insulation between it and each wall, consisting of asbestos chips 37 and two layers 38 of sheet asbestos board. This design solution significantly reduces heat loss to the environment.

It should be noted that in the proposed two-shaft furnace for remelting aluminum scrap, a piggy bank is introduced, formed by the refractory outer side 39, front 40 and rear 41 end walls, a bathtub limited by a hearth 42, a vault 43 and walls. The piggy bank pedestal has two layers 44 laid out of lightweight brick, separated by a layer of asbestos-cardboard 45, as well as a lower layer 46 of asbestos-cardboard. Two layers 44, laid out of lightweight brick, separated by a layer of asbestos board 45, and the bottom layer 46 of asbestos board are in a steel casing 47. The bottom blocks of the MLSP No. 1 of the bottom 42 of the piggy bank are laid on three layers of 48 asbestos-cardboard. Thermal insulation, which consists of two layers of 44 lightweight bricks, three layers of 48 asbestos board and two layers of 45.46 asbestos board, allows you to save the temperature of the metal in the bath of the piggy bank. Hearth blocks МЛСП №1, laid on three layers of asbestos board, have high fire resistance and resistance and allow to increase the service life of the piggy bank. On the pedestal of the piggy bank, a steel box 49 is installed and welded to the steel casing 47, having heat insulation between it and each wall, consisting of asbestos chips 50 and two layers 51 of sheet asbestos board. This design solution significantly reduces heat loss to the environment. Vault 43 of the piggy bank has a double layer of asbestos board 52, which is covered with asbestos chips 53 diluted in liquid glass. This reduces heat loss from the piggy bank.

In the side wall 39 of the piggy bank, a nineteen-mixing medium-pressure injection burner is mounted obliquely to the hearth 42 and is directed to the molten metal bath. The design of a nineteen-mixing medium-pressure injection burner is discussed above. This arrangement of the burners in the furnace and the piggy bank allows to achieve a high melting speed, reduce fumes (according to practical data). The thermal power of all burners is 7776 kW, which makes the furnace highly productive, allowing for forced melting. The practice of operating bathing furnaces of a reflective type with a forced melting mode has shown that in them the burning is 0.4-0.5% lower than in furnaces with a normal melting mode.

In the piggy bank below are two slots 54 for draining molten metal. Each notch 54 is drilled in the flying brick 55, and the flying brick 55 is placed in a metal box 56 of the flying brick and, when laying the back wall 39, is laid in a niche and fixed with wedges in it (not shown). The mullite high-density block of the MLSP No. 11 was taken as a material for summer brick. When replacing a worn summer brick 55, a metal box 56 of the summer brick with the inside brick 55 inside it is removed from the niche, the old summer brick 55 is removed, a new summer brick 55 and a metal box 56 of the summer brick with a new one installed in it are inserted into the metal box 56 of the summer brick 55 55 summer brick put in a niche.

At the same time, the two-shaft reflective furnace with a piggy bank for remelting aluminum scrap has two rotary grooves 57 mounted on brackets 58 welded to the steel duct 49, which rotate during the casting of molten metal and have a rotary bowl 59 in the design, which allows sequentially pouring the weld deposit in the furnace metal in casting equipment located in the service sector with an angle of 143 °. In the side wall 39 of the piggy bank there is a slag window that is closed by the slag door 60. When loading and smelting aluminum scrap, a large amount of harmful flue gases is released, which are trapped by umbrellas 61, and then through gas pipes enter the dust and gas cleaning system, which includes: a mixing chamber 62, smoke exhauster 63, a dust cleaning unit and a gas treatment unit, which makes the process of remelting aluminum scrap environmentally friendly. The layout of the furnace in the melting section is shown in Fig.9. The mixing chamber 62 is designed to dilute flue gases with the air of the workshop, as a result of which the temperature of the flue gases decreases to 150-160 ° C. The draft is created by the DN-12.5 smoke exhaust. Behind the smoke exhaust there is a dust cleaning unit consisting of a chamber 64 for preliminary cleaning of dust and two cyclones 65, in which the final cleaning of dust from flue gases of FIG. 10 is performed. In the preliminary cleaning chamber 64 of the dust cleaning unit, large dust particles are discarded due to centrifugal forces to the walls of the cylindrical chamber 64, slide along the walls and fall under the influence of gravity into the hopper 66, from which they are periodically unloaded and transported to the dump. Medium and fine dust particles come to two cyclones through two supply pipes 67, and each supply pipe is directed tangentially to the cylindrical part of the connected cyclone 65. When entering the cyclones 65, dusty gases acquire a rotational movement, while medium and small dust particles under the action of centrifugal forces are thrown to their walls, and, under the action of gravity, slide down and accumulate in the bunker 68, from which they are periodically unloaded and taken to the dump. The purified air changes direction by 180 ° and enters the conical pipe 69 and is removed through it to the gas cleaning of Fig. 11.

The gas treatment unit is a prefabricated steel cylindrical body 70, in the lower part of which there is a lower rotary loading grill 71 with holes. Above the lower rotary loading grill 71 is the lower loading nozzle 72 of FIG. 12. In the upper cylindrical part of the housing 70 is placed the upper rotary loading grill 73 with holes. Above the upper rotary loading grate 73, there is an upper loading nozzle 74. An adsorbent consisting of: lime powder, activated carbon, birch charcoal, silica gel is poured into the loading nozzles 72 and 74. At the top of the casing 70 there is a cover 75, which is fastened with eight bolts 76 and eight nuts to the upper flange of the casing 70 of the gas cleaning installation. A frame 78 is mounted on the service site 77, on which a blower 79 with an electric motor 80 is located. The service site for the gas treatment installation 77 is supported by four supports 81 and has a ladder 82 on the left. The processed adsorbent and dust are collected in the conical part 83 of the housing 70 and discharged through the discharge pipe 84. Purified gases from cyclones 65 are supplied to the dust and gas cleaning unit through the inlet pipe 85. It is important to note that the furnace can operate both on artificial and natural draft.

The furnace operates on natural draft as follows. The smelter of metal and alloys rises to the service platform 86 and opens the gate 87 on the gas pipe 88, while the thrust in the furnace should be 2-20 DaPa. It is important to note that at the beginning two gates in the mixing chamber: one of which 89 closes or opens the supply of exhaust gases to the smoke exhauster, the other 90 regulates the supply of fresh air to dilute the combustion products with it, are necessarily closed. The burners of the furnace and the burner of the piggy bank are turned on, while the furnace with the piggy bank is calcined according to the technological schedule of calcination, depending on the type of repair performed. After the calcination process, the slots 54 are closed, the shutters 19 of the loading windows open and the metal and alloy smelters are loaded into the calcined furnace unfinished aluminum scrap with an ambient temperature. The flame of four gas injection burners heat the scrap to the melting point. The metal melts and drains through two channels 16 in the wall 12, into the central channel 17 and further from the furnace to the piggy bank. After the molten scrap loaded into the furnace is completely melted, the liquid metal is flux treated in the piggy bank, the metal is thoroughly mixed in the piggy bank and the laboratory confirms the spectral analysis of the grade of the alloy obtained, the metal fillers feed the gutters 57 to the filling equipment, open the grooves 54 and pour the deposited metal from the piggy bank. During the melting process, the scrap melts, the moisture in it evaporates, decomposing into oxygen and hydrogen, and all inclusions remain on the hearth of the furnace, the melting temperature of which is higher than the aluminum alloy. These wastes (alterations: cast iron and steel rings, liners, bushings, studs, pushers, valves, etc.) do not fall into the molten metal, since at the end of smelting they are removed with a scraper from the surface of the furnace bottom. When loading the mixture, melting, casting, flue gases enter the umbrellas 61, pass through the gas pipes 91, 88, enter the chimney 92 and are discharged into the atmosphere. After casting the liquid metal, the bath of the furnace and the piggy bank are cleaned of slag, the slots 54 are plugged and the cycle repeats. The operation of the furnace on natural draft is carried out if the dimensions of the sanitary protection zone of the enterprise allow, during calcination, casting of deposited metal or during a power outage, when the operation of the smoke exhauster and dust and gas cleaning system is impossible.

The operation of the furnace on artificial draft is as follows. The smelter of metal and alloys closes the gate 87, and the gates 89 and 90 are open. The operations are carried out the same as during natural draft melting. The difference is that before loading the charge into the furnace, the adsorbent is loaded into the lower loading pipe 72 and the upper loading pipe 74 of the gas treatment unit, and it is turned on. The combustion products enter the umbrellas 61, pass through the gas pipe 91 into the mixing chamber 62, are diluted in it with the air of the workshop, are pumped by the exhaust fan 63 into the dust cleaning unit, cleaned from dust, and then they enter the gas treatment unit, where the flue gases are cleaned of harmful substances in The “fluidized bed” and the blower 79, the cleaned flue gases are pumped into the chimney 92. The dust and gas cleaning system developed by the author cleans flue gases from dust and harmful substances. The degree of purification is 75-98%. Flue gas cleaning makes the process of smelting aluminum scrap environmentally friendly.

After casting from a liquid metal furnace, metal and alloy smelters open the shutters 19 of the furnace loading windows and clean the bottom of the slag and alterations accidentally caught on it. Next, the shutter 60 of the slag window of the piggy bank opens and the bottom of the piggy bank is cleaned of slag, the slots 54 are closed and the cycle repeats.

So, the proposed gas two-shaft reflective type furnace with a piggy bank for remelting aluminum scrap is highly productive, has a long service life, has low heat loss to the environment due to special thermal insulation, which allows the remelting process to be carried out on natural and artificial draft with a dust and gas cleaning system.

Claims (5)

1. Two-shaft reflective furnace for remelting aluminum scrap, comprising a housing formed by refractory outer side, front and rear end walls, two bathtubs bounded by hearths, a vault and walls, drain gaps and ducts, characterized in that the housing is placed on a pedestal of the furnace having a heat-insulating layer consisting of two layers of lightweight brick, with a double layer of asbestos board between them and a layer below and a layer on top of quartz sand mixed with crushed asbestos chips, and three layers of asbestos board at the top, on which the hearth blocks are laid, while it is equipped with a piggy bank containing a housing formed by refractory outer side, front and rear end walls, a bathtub bounded by a hearth, arch and walls, drain gaps, while the furnace body is placed on the pedestal of the piggy bank and has two layers laid out of lightweight brick, separated by a layer of asbestos-cardboard and a bottom layer of asbestos-cardboard, and the bottom blocks of the piggy bank laid on three layers of asbestos-cardboard, while the burner device contains two nineteen located in the side walls miscible medium-pressure injection burners, five mixers of which are equipped with nozzles and placed in the center with a flame of 2.4 m in length, and fourteen are located on the periphery with a flame of 1.2 m in length when burning a gas-air mixture, and two medium-pressure twelve-mixing burners, four mixers are equipped with nozzles and placed in the center with a flame of 2.1 m long, and eight are located on the periphery with a flame of 1.1 m long when burning a gas-air mixture, installed in the end wall of the furnace, and a nineteen-mixing medium-pressure injection burner is installed obliquely to the bottom of the furnace, while the furnace is re-melted using natural and artificial draft with a dust and gas cleaning system containing a mixing chamber, a smoke exhauster, a dust cleaning unit with a pre-cleaning chamber, two cyclones and an installation gas purification. 2. The furnace according to claim 1, characterized in that it has two tap holes made in quick-change tile bricks in the box, to ensure that they can be replaced without stopping the furnace. 3. The furnace according to claim 1, characterized in that steel boxes are installed on the pedestals of the furnace and the piggy bank, having heat insulation between them and each wall, consisting of asbestos chips, a double layer of sheet asbestos board. 4. The furnace according to claim 1, characterized in that the mixers, nozzles for the mixers and the cast flame-stabilizing tunnel, worn on the gas distribution chamber combining the mixers and on the burner hood, are made of heat-resistant cast iron. 5. The furnace according to claim 1, characterized in that it has two rotary grooves mounted on brackets welded to the box of the piggy bank, which rotate during the pouring of liquid metal and have a rotary bowl in the structure for sequential casting of the metal deposited in the furnace into the casting equipment located in the service sector with an angle of 143 °.

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