Dry treatment and winnowing device and method for high-temperature stainless steel slag

Abstract

The invention provides a high-temperature stainless steel slag dry treatment and winnowing device and method.The device comprises a closed hood, a movable crushing roller, a slag inlet, a crushing bed, a bottom blowing cold box, a slag receiving trolley, a winnowing chamber and a flue gas waste heat recovery system, and is characterized in that the movable crushing roller, the crushing bed and the bottom blowing cold box are arranged in the closed hood; the bottom blowing air cooling box is arranged below the crushing bed, the outer portion of the upper side of the closed cover is communicated with the winnowing chamber, the winnowing chamber is connected with the flue gas waste heat recovery system, the slag inlet is formed in the top of the closed cover in an openable and closable mode, the slag receiving vehicle is arranged at the bottom of the closed cover, and the bottom blowing air cooling box is arranged at the bottom of the closed cover. A multi-stage powder bin and a wind shield are arranged in the winnowing chamber; the system realizes efficient crushing, slag powder winnowing and waste heat recovery of high-temperature stainless steel slag, and has the technical effects of high automation degree, small occupied space, good leakproofness, low system investment and ultra-clean emission.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature steel slag treatment, and in particular, to a dry treatment and air separation device and method for high-temperature stainless steel slag. Background Art

[0002] For the efficient recovery of metal materials such as iron, chromium, and nickel and inorganic material resources in stainless high-temperature steel slag, it is necessary to first perform crushing and separation, and then use methods such as gravity separation and magnetic separation to achieve the separation of materials, so as to obtain targeted resource utilization. The pretreatment process of stainless high-temperature steel slag is a prerequisite for the crushing and magnetic separation treatment of high-temperature steel slag, and more efficient crushing, screening, and magnetic separation of high-temperature steel slag are realized through pretreatment under high-temperature conditions.

[0003] At present, 80% of stainless steel in the world is produced by the two-step method, and 70% of it is smelted in an AOD converter. AOD stainless high-temperature steel slag has the characteristics of high slag temperature, high alkalinity, complex phase transformation during the cooling process, and easy pulverization. The alkalinity of AOD stainless high-temperature steel slag is between 1.9 and 2.5, and CaO and SiO2 in the slag mainly exist in the form of 2CaO·SiO2. During the cooling process of high-temperature steel slag from the molten state, as the temperature decreases, 2CaO·SiO2 continuously undergoes phase transformation, and finally at 850°C, it transforms into γ-C2S. As the temperature decreases, the volume of AOD stainless high-temperature steel slag will expand by 11.45%, resulting in a large amount of powder. The stainless high-temperature steel slag powder with a particle size ≤ 60 mesh can account for more than 80%, which will generate a large amount of dust during production, transportation, stacking, etc., affecting the working environment. Therefore, the treatment of stainless high-temperature steel slag is a necessary process in the production of stainless steel.

[0004] The traditional treatment process of stainless high-temperature steel slag mainly adopts the wet method, spraying water for cooling in the slag pot cooling yard, which occupies a large space and at the same time causes a large amount of polluted wastewater and dust-containing steam, causing great pollution to the environment. Since Cr6+ in the composition of stainless high-temperature steel slag is highly toxic and easily leaches out in a humid environment, a large amount of sewage and sludge will be generated after wet treatment, seriously affecting the environment and at the same time causing waste of the waste heat resources of stainless high-temperature steel slag.

[0005] The tapping temperature of stainless high-temperature steel slag is as high as 1600 °C, and the calorific value per ton of slag exceeds 50 kg of standard coal, which contains a large amount of waste heat resources. If all the waste heat resources are recycled, it is expected to increase the annual economic benefit by hundreds of millions of yuan. At present, the waste heat recovery of high-temperature molten slag such as stainless high-temperature steel slag is often in the experimental research stage, and it is often difficult to realize the full resource utilization of both slag and heat resources. At present, the domestic and foreign focus on high-temperature stainless steel slag is on its secondary utilization and harmless treatment. There is little public information on the waste heat recovery process for high-temperature stainless steel slag, and the waste heat recovery technologies for blast furnace slag and high-temperature steel slag are difficult to be directly applied to stainless high-temperature steel slag. Different from blast furnace slag, stainless high-temperature steel slag is extremely easy to powder when the temperature is lower than about 800 °C, which makes it difficult to apply typical waste heat recovery processes for high-temperature steel slag and blast furnace slag such as air quenching, water quenching, rotary cup and fluidized bed to stainless steel slag. Not only can the waste heat not be effectively recovered, but also serious dust emission or sludge pollution is likely to occur. Summary of the Invention

[0006] To solve the above problems, the present invention provides a dry treatment and air separation device and method for high-temperature stainless steel slag, which replaces the wet flue gas treatment system caused by the water-cooling process by adopting a dry dust removal method, realizes the recovery and utilization of both "slag and heat" resources, and has the technical effects of high equipment automation level, small space occupation, low system investment, high waste heat recovery rate, and clean production.

[0007] The present invention provides a dry treatment and air separation device for high-temperature stainless steel slag, including a slag tank, a closed hood, a movable crushing roller, a slag inlet, a crushing bed, a bottom air-cooling box, a slag receiving vehicle, a slag discharge port, an air separation chamber and a flue gas waste heat recovery system. The slag inlet is arranged at the upper part of the closed hood for pouring the high-temperature steel slag in the slag tank into the crushing bed through the slag inlet. The slag discharge port is arranged at the lower part of the closed hood on the side far from the slag inlet. The movable crushing roller, the crushing bed and the bottom air-cooling box are arranged in the closed hood. The bottom air-cooling box is arranged below the crushing bed. The upper side outside of the closed hood is communicated with the air separation chamber. The air separation chamber is connected with the flue gas waste heat recovery system. The slag receiving vehicle is arranged at the bottom of the closed hood. The air separation chamber is provided with a multi-stage powder bin and a wind baffle.

[0008] In an optional embodiment, the movable crushing roller is movably arranged above the crushing bed, and one or more bottom air-cooling boxes are arranged below the crushing bed. One or more cold air pipes are communicated with the bottom of the bottom air-cooling box, and the cold air pipes are connected with a blower. The cold air pipes are used for evenly distributing the cold air blown out by the blower to cool the high-temperature steel slag through the crushing bed.

[0009] In an alternative embodiment, the crushing bed includes a cold slag cushion layer and a grate plate. The cold slag cushion layer is disposed on the grate plate to insulate the high-temperature steel slag, thereby protecting the grate plate from high-temperature deformation. The grate plate is composed of grate bars arranged in parallel and staggered. The thickness of the grate plate is not less than 20 mm, and the gap width between the grate bars is 5 - 40 mm, ensuring that gas can pass through while preventing high-temperature steel slag particles from leaking under the grate plate. The thickness of the cold slag cushion layer is not less than 50 mm.

[0010] In an alternative embodiment, the grate bar is a U-shaped open bar with two vertical plates and one horizontal plate. The grate plate includes an upper grate bar layer and a lower grate bar layer. Both the upper grate bar layer and the lower grate bar layer are composed of adjacent grate bars arranged in parallel. There are plate holes between the adjacent grate bars of the upper grate bar layer and the lower grate bar layer. The openings of the grate bars of the upper grate bar layer and the lower grate bar layer are arranged opposite to each other. The two adjacent vertical plates of the grate bars in the upper grate bar layer are located within the opening of one grate bar in the lower grate bar layer, and the two adjacent vertical plates of the grate bars in the lower grate bar layer are located within the opening of one grate bar in the upper grate bar layer.

[0011] In an alternative embodiment, the moving crushing roller further includes crushing teeth, which are evenly arranged on the moving crushing roller shaft. 8 - 12 crushing teeth are arranged every 360 degrees in the circumferential direction, and the included angle between two adjacent crushing teeth is 30 - 45 degrees. The materials of the moving crushing roller shaft and the crushing teeth are heat-resistant alloy steel. The moving crushing roller rotates at a certain rate, which is used to stir and crush the high-temperature steel slag while realizing the slag pushing function.

[0012] In an alternative embodiment, the blower conveys cold air with a certain pressure into the closed hood. Due to the large temperature difference between the high-temperature steel slag and the cold air, the high-temperature steel slag begins to cool itself. When it drops to the self-pulverization critical temperature of 800 °C, it starts continuous self-pulverization, generating fine powder with a pulverization fineness of 60 - 180 mesh. The self-pulverized dust mixes with the heated air to form dust-containing high-temperature flue gas. Since the high-temperature steel slag is gradually pulverized and the fine powder cannot adhere to the high-temperature steel slag, it cannot prevent the high-temperature steel slag from continuing to cool. The high-temperature steel slag is completely pulverized, and finally more than 95% of the fine powder and larger fragments below 20 mm are separated. The slag particles and slag blocks on the crushing bed then enter the secondary treatment line. With continuous cold air, the pulverized slag powder enters the air separation chamber along with the high-temperature flue gas, and the stainless high-temperature steel slag dust is collected at a high temperature.

[0013] In an optional embodiment, the air separation chamber captures slag powder of different particle sizes under the action of gravity to form a stainless high-temperature steel slag fine powder product, and the flue gas is discharged after waste heat recovery through the induced draft duct. A coarse slag powder bin of 5 to 20 mm, a medium slag powder bin of 2 to 5 mm and a fine slag powder bin of less than 2 mm are provided in the air separation chamber along the direction of flue gas flow, one or more wind shields are provided on the upper part of the coarse slag powder bin and / or the medium slag powder bin and / or the fine slag powder bin, and the wind shield is inclined clockwise by 5-85 degrees to change the wind direction in the local area of ​​the air separation chamber to avoid wind directly discharged from the air separation equipment and the occurrence of local turbulence.

[0014] In an optional embodiment, the coarse slag powder bin, medium slag powder bin and fine slag powder bin of the air separation chamber are respectively provided with a coarse slag powder outlet, a medium slag powder outlet and a fine slag powder outlet at the bottom, and controllable valves are installed at the ends of the slag powder outlets. Each controllable valve has two valve baffles. The size of the area at the outlet is adjusted by changing the intersection angle of the two valve baffles to control the rate at which the slag powder leaves the air separation chamber.

[0015] In an optional embodiment, the flue gas waste heat recovery system includes an induced draft duct, a flue gas boiler, a bag dust collector, an induced draft fan and a chimney connected in sequence, one end of the induced draft duct is connected to the air outlet of the air selection chamber, and the other end is connected to the flue gas boiler.

[0016] In an optional embodiment, in the flue gas boiler, the heat in the high-temperature flue gas is exchanged with the working fluid water doing work in the flue gas boiler, completing the "gas-liquid" heat exchange, so that the working fluid water temperature in the flue gas boiler rises, forming high-quality saturated water vapor; the gas still containing dust after the temperature drops enters the bag filter to capture the dust again, and the bag filter is connected to the chimney through the induced draft fan to discharge the dust-removed flue gas, and the closed hood, induced draft duct, and flue gas boiler are insulated with inorganic thermal insulation cotton.

[0017] The present invention also provides a method for dry treatment and air separation of high-temperature stainless steel slag, which uses the above-mentioned dry treatment and air separation device of high-temperature stainless steel slag, and comprises the following steps:

[0018] Step S1. Load the high-temperature slag, open the slag discharge port on the sealed cover, close the slag discharge port, and pour the slag pot containing the high-temperature slag onto the crushing bed by crane, and the high-temperature slag falls onto the cold slag cushion layer;

[0019] Step S2. high-temperature steel slag crushing and convection heat exchange, start the blower, blow cold air into the bottom blowing cold air box through the cold air pipe, and then cool the high-temperature steel slag through the grate plate and the cold slag cushion; at the same time, start the mobile crushing roller, move the mobile crushing roller back and forth, and stir and crush the high-temperature steel slag through the crushing teeth on the mobile crushing roller to solidify into slag blocks and slag particles; the bottom blowing cold air and the high-temperature steel slag perform convection heat exchange during the stirring and crushing process;

[0020] Step S3. The high-temperature steel slag is pulverized to form high-temperature dusty hot flue gas and air-selected slag powder. Through continuous cold air, after the stainless high-temperature steel slag is solidified to a certain particle size within a certain period of time, when the stainless high-temperature steel slag drops below the self-pulverization critical temperature of 800°C, continuous self-pulverization begins. The pulverized slag powder is mixed with the air heated after heat exchange to form high-temperature dusty hot flue gas, which enters the air separation chamber and is separated into slag powder bins with different particle sizes under the action of gravity;

[0021] Step S4. Recovery of the high-temperature waste heat of the flue gas. While blowing air for cooling, start the flue gas boiler, bag filter, and induced draft fan of the flue gas waste heat recovery system. The high-temperature flue gas passing through the air separation chamber is sent into the flue gas boiler through the induced draft pipe. The saturated steam generated by the flue gas boiler is used for drying, heating, or power generation to recover the waste heat; the flue gas cooled by the flue gas boiler is discharged to the outside through the dust collector, induced draft fan, and chimney of the waste heat recovery system.

[0022] In an optional embodiment, in step S3, it further includes that under the action of continuous cold air, the stainless high-temperature steel slag gradually cools down and pulverizes, and the fine powder cannot adhere to the high-temperature steel slag and cannot prevent the high-temperature steel slag from continuing to cool down. The pulverization of the high-temperature steel slag ends to separate the fine powder less than 20 mm and the larger fragments; the movable crushing roller pushes the remaining slag blocks and slag particles on the crushing bed after air separation towards the slag discharge port for slag discharge. The slag discharge port is opened in a pulley manner to discharge slag to the slag receiving vehicle, and the slag receiving vehicle transports the slag particles and slag blocks to the secondary line.

[0023] The present invention uses a crushing bed as the carrier for high-temperature steel slag treatment, uses a crusher to efficiently crush high-temperature steel slag, uses a bottom-blowing cold air box to air-cool high-temperature steel slag, uses an air separation chamber to air-select and capture stainless high-temperature steel slag powder, and uses a heat exchanger and a generator to recover and generate electricity from the waste heat of high-temperature steel slag. The high-temperature steel slag is poured into the crushing bed, and at the same time, cold air is introduced from the bottom to air-cool and solidify and cool down the high-temperature steel slag. The crusher rotates at a certain rate, while crushing the high-temperature steel slag, it can also achieve the function of pushing the slag. At the same time, air selection is carried out on the high-temperature steel slag powder for subsequent utilization.

[0024] The slag powder in the air separation chamber of the present invention has a low metal content and is generally less than 20 mm in size, and can be used to make cement, glass-ceramics, and road materials, or as a soil conditioner or fertilizer raw material. The flue gas boiler is used to recover the waste heat of the high-temperature flue gas to generate high-quality steam, which can be used for drying, heating, power generation, etc. This equipment has a high crushing capacity, greatly improves the treatment efficiency of high-temperature steel slag, and at the same time, the high-temperature flue gas obtained by air-cooling heat exchange during the crushing process can be used for waste heat recovery and power generation.

[0025] The present invention can achieve a power generation of 10 - 20 kWh per ton of slag, with significant economic benefits in waste heat recovery. The proportion of high-temperature steel slag with a particle size < 50 mm after crushing of high-temperature steel slag is as high as over 80%, and the pulverization rate of high-temperature steel slag is significantly increased. The high-temperature flue gas is cooled after heat exchange and discharged organizedly through a dust collector, with the dust emission concentration lower than 10 mg / m 3 .

[0026] The present invention realizes the efficient crushing of high-temperature steel slag, slag powder air separation and waste heat recovery in terms of devices and methods. It cancels the water-cooling system device for high-temperature steel slag, and replaces the wet flue gas treatment system caused by the previous water-cooling process with a simple dry dust removal method, having the technical effects of convenient production operation, high automation degree, small floor space, good airtightness, low system investment and ultra-clean emission. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0028] Figure 1 It is a schematic diagram of the overall operation of a dry treatment and air separation device for high-temperature stainless steel slag provided by the present invention;

[0029] Figure 2 It is a schematic diagram of the crushing bed structure of a dry treatment and air separation device for high-temperature stainless steel slag provided by the present invention;

[0030] Figure 3 It is a general flowchart of a dry treatment and air separation method for high-temperature stainless steel slag provided by the present invention.

[0031] Description of the reference numerals in the drawings:

[0032] 1 - slag pot, 2 - airtight cover, 3 - movable crushing roller, 4 - slag inlet, 5 - cold slag cushion layer, 6 - grate plate, 7 - crushing bed, 8 - blower, 9 - cold air pipe, 10 - bottom blowing cold air box, 11 - slag receiving truck, 12 - slag discharge port, 13 - controllable valve, 14 - induced air pipe, 15 - flue gas boiler, 16 - bag filter, 17 - induced draft fan, 18 - chimney, 19 - slag discharge port, 20 - high-temperature steel slag, 21 - wind baffle, 22 - crushing teeth, 23 - grate bars, 24 - plate holes. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] To enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0035] See the attached Figure 1-2 , the present invention provides a dry treatment and air separation device for high-temperature stainless steel slag, including a slag tank 1, a closed hood 2, a movable crushing roller 3, a slag inlet 4, a crushing bed 7, a bottom blowing air-cooling box 10, a slag receiving vehicle 11, an air separation chamber 12, and a flue gas waste heat recovery system. The movable crushing roller 3, the crushing bed 7, and the bottom blowing air-cooling box 10 are arranged in the closed hood 2. The upper side outside the closed hood 2 is communicated with the air separation chamber 12. The air separation chamber 12 is connected to the flue gas waste heat recovery system. The slag inlet 4 is disposed at the top of the closed hood 2 in an openable and closable manner. The slag receiving vehicle 11 is disposed at the bottom of the closed hood 2. A multi-stage powder bin and a wind baffle 21 are arranged in the air separation chamber 12.

[0036] Further, it also includes a slag tank 1. The slag tank 1 is located above the closed hood 3 and can move back and forth under the action of a crane, and is used to pour the high-temperature steel slag 5 in the slag tank 1 into the cold slag cushion layer 5 of the crushing bed 7 through the slag pouring port 4.

[0037] Further, the movable crushing roller 3 is movably arranged above the crushing bed 7, and one or more of the bottom blowing air-cooling boxes 10 are arranged below the crushing bed 7. One or more cold air pipes 9 are connected to the bottom of the bottom blowing air-cooling box 10, and the cold air pipes 9 are connected to a blower 8.

[0038] Further, the crushing bed 7 includes a cold slag cushion layer 5 and a grate plate 6. The cold slag cushion layer 5 is arranged on the grate plate 6. The cold slag cushion layer 5 is arranged above the grate plate 5 to insulate the high-temperature steel slag 20 to protect the grate plate 6 from high-temperature deformation, ensure the passage of gas, and avoid high-temperature steel slag particles from leaking under the grate plate; the grate plate 6 is composed of grate bars 23 arranged in parallel and staggered.

[0039] Further, the grate bar 23 is a U-shaped open bar with two vertical plates and one horizontal plate. The grate plate 6 includes an upper grate bar layer and a lower grate bar layer. Both the upper grate bar layer and the lower grate bar layer are composed of adjacent parallel grate bars 23. There are plate holes 24 between the adjacent grate bars 23 of the upper grate bar layer and the lower grate bar layer. The openings of the grate bars 23 in the upper grate bar layer and the lower grate bar layer are arranged opposite to each other. The adjacent vertical plates of the two grate bars 23 in the upper grate bar layer are located within the opening of one grate bar 23 in the lower grate bar layer, and the adjacent vertical plates of the two grate bars 23 in the lower grate bar layer are located within the opening of one grate bar 23 in the upper grate bar layer.

[0040] Further, the movable crushing roller 3 further includes crushing teeth 22. The crushing teeth 22 are evenly arranged on the shaft of the movable crushing roller 3. 8 - 12 crushing teeth 22 are arranged every 360 degrees in the circumferential direction, and the included angle between two adjacent crushing teeth 22 is 30 - 45 degrees. The materials of the shaft of the movable crushing roller 3 and the crushing teeth 22 are heat-resistant alloy steel.

[0041] Further, a coarse slag powder bin, a medium slag powder bin and a fine slag powder bin are sequentially arranged in the air separation chamber 12 along the flue gas flow direction. One or more wind baffle plates 21 are arranged on the upper part of the coarse slag powder bin and / or the medium slag powder bin and / or the fine slag powder bin. The wind baffle plate 21 is inclined at 5 - 85 degrees clockwise. The wind baffle plate 21 is used to change the wind direction in a local range of the air separation chamber 12 to avoid the direct discharge of wind from the air separation equipment and the occurrence of local turbulence phenomenon.

[0042] Further, a coarse slag powder outlet, a medium slag powder outlet and a fine slag powder outlet are respectively arranged at the bottoms of the coarse slag powder bin, the medium slag powder bin and the fine slag powder bin in the air separation chamber 12. Control valves 13 are installed at the ends of the slag powder outlets. Each control valve 13 has two valve baffles. The area at the outlet is adjusted by changing the included angle of the two valve baffles to control the rate of the slag powder leaving the air separation chamber 12.

[0043] Further, the air separation chamber 12 is used for sorting and storing the slag powder generated from self-pulverization during the air-cooling process of stainless steel high-temperature steel slag. The slag powder in the air separation chamber has a low metal content and is generally less than 20 mm in size, and can be used to make cement, glass-ceramics and road materials, or used as a soil conditioner or fertilizer raw material.

[0044] Further, the flue gas waste heat recovery system includes an induced draft pipe 14, a flue gas boiler 15, a bag filter 16, an induced draft fan 17 and a chimney 18 which are sequentially connected. One end of the induced draft pipe 14 is connected to the air outlet of the air separation chamber 12, and the other end is connected to the flue gas boiler 15.

[0045] Further, the closed hood 2, the induced draft pipe 14 and the flue gas boiler 15 are heat-insulated with inorganic heat-insulating cotton.

[0046] Furthermore, the crusher crushes the high-temperature steel slag, the blower blows air to cool the high-temperature steel slag, and the crusher, heat exchanger, generator, dust collector, induced draft fan, and chimney operate simultaneously.

[0047] Furthermore, the thickness of the grate plate 6 is not less than 20 mm, the width of the gaps 24 between the grate bars 23 is 5 - 40 mm, and the thickness of the cold slag cushion layer 5 is not less than 50 mm.

[0048] Furthermore, a slag discharge port 19 is provided on one side of the crushing bed 7 away from the slag inlet 4. The movable slag receiving truck 11 is arranged at the bottom of the slag discharge port 19. The slag receiving truck 11 is located below the slag discharge port 19 and is used to transport the remaining slag particles and lumps on the crushing bed 7 after air separation to the secondary treatment line.

[0049] Furthermore, the slag inlet 4 is provided above the closed hood 2 and is used to pour the high-temperature steel slag 20 in the slag pot 1 onto the cold slag cushion layer 5 of the crushing bed 7 through the slag inlet 4.

[0050] Furthermore, the movable crushing roller 3 is located above the crushing bed 7 and is used to stir and crush the high-temperature steel slag. The crushing roller 3 rotates at a certain rate, crushing the high-temperature steel slag while also achieving the function of pushing the slag.

[0051] Furthermore, the bottom air-blowing cold box 10 is provided below the crushing bed 7 and is used to evenly distribute the cold air blown out by the blower 8 to cool the high-temperature steel slag through the grate plate 6 and the cold slag cushion layer.

[0052] Furthermore, when the blower 8 conveys cold air with a certain pressure into the closed hood 2, due to the large temperature difference between the high-temperature steel slag and the cold air, the high-temperature steel slag begins to cool itself. When it drops to the self-pulverization critical temperature of 800 °C, it starts continuous self-pulverization, generating fine powder. The pulverization fineness varies from 60 to 180 mesh. The self-pulverized dust mixes with the heated air to form dust-containing hot flue gas.

[0053] Furthermore, since the high-temperature steel slag 20 is gradually pulverized and the fine powder cannot adhere to the high-temperature steel slag 20 to prevent the high-temperature steel slag 20 from continuing to cool down, the high-temperature steel slag is completely pulverized. Eventually, more than 95% of the fine powder below 20 mm and larger fragments are separated. At the same time, under the suction of the induced draft fan 17, the dust-containing hot flue gas is sent into the air separation chamber 12 for dust collection of the stainless high-temperature steel slag at high temperature.

[0054] Furthermore, through continuous cold air, the pulverized slag powder of the high-temperature stainless steel slag enters the air separation chamber 12 along with the hot flue gas. Different particle sizes of slag powder are collected under the action of gravity to form a fine powder product of the stainless high-temperature steel slag, and the flue gas is discharged after heat recovery through the induced draft pipe.

[0055] Furthermore, the air separation chamber is respectively provided with a coarse slag powder bin for 5 - 20 mm slag powder, a medium slag powder bin for 2 - 5 mm slag powder, and a fine slag powder bin for slag powder less than 2 mm, which can be respectively used for making cement, microcrystalline glass and road materials, or for soil conditioner or fertilizer raw materials.

[0056] Furthermore, in the flue gas boiler 15, the heat in the high-temperature flue gas is exchanged to the working medium water doing work in the flue gas boiler 15 to complete the "gas-liquid" heat exchange, so that the temperature of the working medium water in the flue gas boiler 15 rises, forming high-quality saturated water vapor, which can be used for drying, heating, power generation, etc., while the flue gas temperature drops.

[0057] Furthermore, the flue gas boiler 15 is also connected to a bag filter 16 through a pipeline. The gas still containing dust after the temperature drops enters the bag filter 16 to capture dust again. The bag filter 16 is connected to a chimney 18 through an induced draft fan 17 for discharging the dust-removed flue gas to the outside.

[0058] Furthermore, the inner diameter of the slag inlet 4 is not less than 2000 mm. The slag inlet 4 is opened by a pulley method for slag inlet; the moving crushing roller 3 pushes the remaining slag blocks and slag particles on the air separation crushing bed 7 towards the slag discharge port 19 for slag discharge. The slag discharge port 19 is opened by a pulley method for discharging slag to the slag receiving vehicle 11.

[0059] Furthermore, the thickness of the grate plate 6 is not less than 20 mm. The grate plate 6 is composed of mutually staggered grate bars 23. Plate holes 24 are arranged between the grate bars 23, and the gap width of the plate holes 24 is 5 - 40 mm, ensuring that gas passes through while preventing high-temperature steel slag particles from leaking under the grate plate; a cold slag cushion layer 5 is arranged above the grate plate 5 to insulate the high-temperature steel slag 20 to protect the grate plate 6 from high-temperature deformation. The thickness of the cold slag cushion layer 5 is not less than 50 mm.

[0060] See Appendix Figure 3 , the present invention also provides a method for dry treatment and air separation of high-temperature stainless steel slag, using the above-mentioned high-temperature stainless steel slag dry treatment and air separation device, including the following steps:

[0061] Step S1. Feeding high-temperature steel slag, opening the slag pouring port 4 on the closed cover 2, closing the slag discharge port 11, and hoisting the slag tank 1 containing high-temperature steel slag 20 by a crane and pouring it onto the crushing bed 7. The high-temperature steel slag 20 falls onto the cold slag cushion layer 5;

[0062] Step S2. Crushing high-temperature steel slag and convective heat transfer, starting the blower 8, blowing cold air into the bottom blowing cold air box 10 through the cold air pipe 9, and then cooling the high-temperature steel slag 20 through the grate plate 6 and the cold slag cushion layer 5 by air cooling; at the same time, starting the moving crushing roller 3, the moving crushing roller 3 reciprocates, and stirs and crushes the high-temperature steel slag 7 through the crushing teeth 22 on the moving crushing roller 3 to solidify into slag blocks and slag particles; the bottom blowing cold air and the high-temperature steel slag 20 conduct convective heat transfer during the stirring and crushing process;

[0063] Step S3. The high-temperature steel slag is pulverized to form high-temperature dusty hot flue gas and air-selected slag powder. Through continuous cold air, after the stainless high-temperature steel slag is solidified to a certain particle size within a certain period of time, when the stainless high-temperature steel slag drops below the self-pulverization critical temperature of 800°C, it starts continuous self-pulverization. The pulverized slag powder is mixed with the air heated after heat exchange to form high-temperature dusty hot flue gas, which enters the air separation chamber 12 and is sorted into slag powder bins of different particle sizes under the action of gravity.

[0064] Step S4. Recovery of the high-temperature waste heat of the flue gas. While blowing air for cooling, start the flue gas boiler 15, bag filter 16 and induced draft fan 17 of the flue gas waste heat recovery system. The high-temperature flue gas passing through the air separation chamber 12 is sent into the flue gas boiler 15 through the induced draft pipe 14. The saturated steam generated by the flue gas boiler 15 is used for drying, heating or power generation to recover the waste heat. The flue gas cooled by the flue gas boiler 15 is discharged externally through the dust collector 16, induced draft fan 17 and chimney 18 of the waste heat recovery system.

[0065] Further, in step S3, it also includes that under the action of continuous cold air, the stainless high-temperature steel slag 20 gradually cools down and pulverizes. The fine powder cannot adhere to the high-temperature steel slag and cannot prevent the high-temperature steel slag from continuing to cool down. The pulverization of the high-temperature steel slag ends to separate the fine powder less than 20 mm and the larger fragments. The moving crushing roller 3 pushes the remaining slag blocks and slag particles on the crushing bed 7 after air separation towards the slag discharge port 19 for slag discharge. The slag discharge port 19 is opened in a pulley manner to discharge slag to the slag receiving vehicle 11, and the slag receiving vehicle 11 transports the slag particles and slag blocks to the secondary line.

[0066] In an embodiment provided by the present invention, the slag pouring time of a single slag ladle 1 is 2 - 6 minutes, and the processing time of the moving crushing roller 3 is 10 - 60 minutes; the rotation speed of the moving crushing roller 3 is 3 - 15 revolutions per minute. The processing rate of the high-temperature steel slag can be increased by increasing the rotation speed of the moving crushing roller 3, and vice versa, the processing rate of the high-temperature steel slag can be reduced.

[0067] In an embodiment provided by the present invention, the air volume of the cooling air blown for the high-temperature steel slag is 1000 - 4000 m 3 / ton of stainless high-temperature steel slag. The cooling speed of the stainless high-temperature steel slag and the air separation speed of the slag powder can be accelerated by increasing the air volume of the blown air, and the particle size distribution of the slag powder in the air separation chamber can be controlled to become larger. On the contrary, the cooling speed of the stainless high-temperature steel slag can be reduced, and the particle size distribution of the slag powder in the air separation chamber can be controlled to become smaller.

[0068] In an embodiment provided by the present invention, the slag discharging temperature of the slag blocks and slag particles at the slag discharge port 12 is controlled at 100 - 200°C. After the stainless high-temperature steel slag is crushed, more than 80% of the high-temperature steel slag with particle sizes of the remaining slag blocks and slag particles less than 50 mm.

[0069] In an embodiment provided by the present invention, the blower 8 provides high-temperature steel slag cooling gas as normal-temperature air. The high-temperature flue gas obtained by heat exchange with the high-temperature steel slag 20 has a temperature of 250 - 500 °C. The high-temperature flue gas is cooled to below 150 °C through heat exchange in the heat exchanger 15, and then is discharged to the outside in an organized manner through the bag filter 16, the induced draft fan 17, and the chimney 18. The dust concentration of the discharged flue gas is lower than 10 mg / m 3 The saturated water vapor obtained by heat exchange of the high-temperature flue gas in the heat exchanger 15 can be used for drying, heating, power generation, etc. For example, when used for power generation, the power generation per ton of high-temperature steel slag is 10 - 20 kWh.

[0070] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0071] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-temperature stainless steel slag dry treatment and air separation device, comprising a slag pot (1), a closed cover (2), a movable crushing roller (3), a slag inlet (4), a crushing bed (7), a bottom blowing air cooling box (10), a slag receiving vehicle (11), a slag discharge port (19), an air separation chamber (12) and a flue gas waste heat recovery system, characterized in that: The slag inlet (4) is arranged at the upper part of the closed cover (2) and is used to pour the high-temperature steel slag (20) in the slag pot (1) onto the crushing bed (7) through the slag inlet (4). The slag discharge port (19) is arranged at the lower part of the closed cover (2) away from the slag inlet (4). The movable crushing roller (3), the crushing bed (7) and the bottom-blowing air cooling box (10) are arranged in the closed cover (2). The bottom-blowing air cooling box (10) is arranged below the crushing bed (7). The upper side of the closed cover (2) is externally connected to the air separation chamber (12). The air separation chamber (12) is connected to the flue gas waste heat recovery system. The slag receiving vehicle (11) is arranged at the bottom of the closed cover (2). The air separation chamber (12) is provided with a multi-stage powder bin and a wind shield (21).

2. The high-temperature stainless steel slag dry treatment and air separation device according to claim 1, characterized in that: The movable crushing roller (3) is movably arranged on the upper part of the crushing bed (7), and one or more bottom-blowing air cooling boxes (10) are arranged on the lower part of the crushing bed (7). The bottom of the bottom-blowing air cooling box (10) is connected to one or more cold air pipes (9), and the cold air pipes (9) are connected to the blower (8). The cold air pipes (9) are used to evenly distribute the cold air blown by the blower (8) to cool the high-temperature steel slag through the crushing bed (7).

3. The high-temperature stainless steel slag dry treatment and air separation device according to claim 2, characterized in that: The crushing bed (7) comprises a cold slag cushion layer (5) and a grate plate (6). The cold slag cushion layer (5) is arranged on the grate plate (6) to insulate the high-temperature steel slag (20) so as to protect the grate plate (6) from high-temperature deformation. The grate plate (6) is composed of mutually parallel grate bars (23) arranged in a staggered manner. The thickness of the grate plate (6) is not less than 20 mm. The width of the gap between the grate bars (23) is 5-40 mm, which ensures the passage of gas while preventing high-temperature steel slag particles from leaking under the grate plate. The thickness of the cold slag cushion layer (5) is not less than 50 mm.

4. The high-temperature stainless steel slag dry treatment and air separation device according to claim 3, characterized in that: The grate bar (23) is a U-shaped open bar material having two vertical plates and one horizontal plate. The grate plate (6) comprises an upper grate bar layer and a lower grate bar layer. The upper grate bar layer and the lower grate bar layer are both composed of grate bars (23) arranged adjacent to each other in parallel. Plate holes (24) are provided between the grate bars (23) arranged adjacent to each other in the upper grate bar layer and the lower grate bar layer. The openings of the grate bars (23) in the upper grate bar layer and the lower grate bar layer are arranged opposite to each other. The vertical plates adjacent to the two grate bars (23) in the upper grate bar layer are both located in the opening of a grate bar (23) in the lower grate bar layer, and the vertical plates adjacent to the two grate bars (23) in the lower grate bar layer are both located in the opening of a grate bar (23) in the upper grate bar layer.

5. The high-temperature stainless steel slag dry treatment and air separation device according to claim 2, characterized in that: The movable crushing roller (3) further comprises crushing teeth (22), which are evenly arranged on the shaft of the movable crushing roller (3), with 8 to 12 crushing teeth (22) arranged every 360 degrees in the circumferential direction, and the angle between two adjacent crushing teeth (22) is 30 to 45 degrees; the shaft of the movable crushing roller (3) and the crushing teeth (22) are made of heat-resistant alloy steel, and the movable crushing roller (3) rotates at a certain speed, so as to stir and crush the high-temperature steel slag (20) while achieving a slag pushing effect.

6. The high-temperature stainless steel slag dry treatment and air separation device according to claim 3, characterized in that: The blower (8) delivers cold air with a certain pressure into the closed cover (2). Since the high-temperature steel slag (20) has a huge temperature difference with the cold air, the high-temperature steel slag itself begins to cool down and drops to the self-powdering critical temperature of 800°C. It begins to self-powder continuously to produce fine powder with a powdering fineness of 60 to 180 meshes. The self-powdered dust mixes with the heated air to form dusty high-temperature flue gas. Since the high-temperature steel slag (20) is gradually powdered, the fine powder cannot adhere to the high-temperature steel slag (20) and cannot prevent the high-temperature steel slag (20) from continuing to cool down. The high-temperature steel slag (20) is completely powdered, and finally more than 95% of the fine powder below 20 mm and larger fragments are separated. The slag particles and slag blocks on the crushing bed (7) enter the secondary processing line. Through continuous cold air, the powdered slag powder enters the air separation chamber (12) along with the high-temperature flue gas, and the stainless high-temperature steel slag dust is captured under high temperature.

7. The high-temperature stainless steel slag dry treatment and air separation device according to claim 1, characterized in that: The air separation chamber (12) captures slag powder of different particle sizes under the action of gravity to form a stainless high-temperature steel slag fine powder product. The flue gas is discharged after the waste heat is recovered through the induced draft duct. The air separation chamber (12) is provided with a coarse slag powder bin of 5 to 20 mm, a medium slag powder bin of 2 to 5 mm and a fine slag powder bin of less than 2 mm in sequence along the flue gas flow direction. One or more wind shields (21) are provided on the upper part of the coarse slag powder bin and / or the medium slag powder bin and / or the fine slag powder bin. The wind shield (21) is inclined clockwise at 5 to 85 degrees to change the wind direction in the local range of the air separation chamber (12) to prevent the wind from being directly discharged from the air separation equipment and the occurrence of local turbulence.

8. The high-temperature stainless steel slag dry treatment and air separation device according to claim 6, characterized in that: The coarse slag powder bin, the medium slag powder bin and the fine slag powder bin of the air separation chamber (12) are respectively provided with a coarse slag powder outlet, a medium slag powder outlet and a fine slag powder outlet at the bottom, and controllable valves (13) are installed at the ends of the slag powder outlets. Each controllable valve (13) has two valve baffles. The size of the area at the outlet is adjusted by changing the intersection angle of the two valve baffles to control the rate at which the slag powder leaves the air separation chamber (12).

9. The high-temperature stainless steel slag dry treatment and air separation device according to claim 1, characterized in that: The flue gas waste heat recovery system comprises an induced draft duct (14), a flue gas boiler (15), a bag filter (16), an induced draft fan (17) and a chimney (18) which are connected in sequence, wherein one end of the induced draft duct (14) is connected to the air outlet of the air selection chamber (12), and the other end is connected to the flue gas boiler (15).

10. The high-temperature stainless steel slag dry treatment and air separation device according to claim 9, characterized in that: In the flue gas boiler (15), heat in the high-temperature flue gas is exchanged with the working medium water doing work in the flue gas boiler (15), completing the "gas-liquid" heat exchange, so that the working medium water temperature in the flue gas boiler (15) rises, forming high-quality saturated water vapor; after the temperature drops, the gas still containing dust enters the bag filter (16) to capture the dust again; the bag filter (16) is connected to the chimney (18) through the induced draft fan (17) to discharge the flue gas after dust removal; the closed cover (2), the induced draft pipe (14), and the flue gas boiler (15) are insulated with inorganic thermal insulation cotton.

11. A method for dry treatment and air separation of high temperature stainless steel slag, using a device for dry treatment and air separation of high temperature stainless steel slag as claimed in any one of claims 1 to 10, characterized in that: The steps include: Step S1. Loading high-temperature steel slag, opening the slag pouring port (4) on the closed cover (2), closing the slag discharge port (11), and pouring the slag pot (1) containing the high-temperature steel slag (20) onto the crushing bed (7) via a crane, and the high-temperature steel slag (20) falls onto the cold slag cushion (5); Step S2. high-temperature steel slag crushing and convection heat exchange, start the blower (8), blow cold air into the bottom blowing cold air box (10) through the cold air pipe (9), and then cool the high-temperature steel slag (20) through the grate plate (6) and the cold slag cushion layer (5); at the same time, start the mobile crushing roller (3), the mobile crushing roller (3) reciprocates, and the crushing teeth (22) on the mobile crushing roller (3) stir and crush the high-temperature steel slag (7) to solidify into slag blocks and slag particles; the bottom blowing cold air and the high-temperature steel slag (20) perform convection heat exchange during the stirring and crushing process; Step S3. The high-temperature steel slag is pulverized to form high-temperature dusty hot flue gas and air-selected slag powder. After a certain period of time, the stainless high-temperature steel slag is solidified and reaches a certain particle size through continuous cold air. After the stainless high-temperature steel slag drops to the self-pulverization critical temperature of 800°C, continuous self-pulverization begins. The pulverized slag powder is mixed with the air heated after heat exchange to form high-temperature dusty hot flue gas that enters the air-selection chamber (12), and enters the slag powder bins of different particle sizes for sorting under the action of gravity. Step S4. recovering the high-temperature waste heat of the flue gas. While cooling by blast, the flue gas boiler (15), bag filter (16) and induced draft fan (17) of the flue gas waste heat recovery system are started. The high-temperature flue gas passing through the air selection chamber (12) is sent to the flue gas boiler (15) through the induced draft pipe (14). The saturated water vapor generated by the flue gas boiler (15) is used for drying, heating or power generation to recover waste heat. The flue gas cooled by the flue gas boiler (15) is discharged through the dust collector (16), induced draft fan (17) and chimney (18) of the waste heat recovery system.

12. The method for dry treatment and air separation of high temperature stainless steel slag according to claim 11, characterized in that: The step S3 also includes cooling the stainless high-temperature slag (20) and gradually pulverizing it under the action of continuous cold wind, so that the fine powder cannot adhere to the high-temperature slag and cannot prevent the high-temperature slag from continuing to cool down. The pulverization of the high-temperature slag is completed to separate the fine powder smaller than 20 mm from the larger fragments; the crushing roller (3) is moved to push the slag blocks and slag particles remaining on the crushing bed (7) after air selection to the slag discharge port (19) for slag discharge, and the slag discharge port (19) is opened by a pulley to discharge the slag to the slag receiving vehicle (11), and the slag receiving vehicle (11) transports the slag particles and slag blocks to the secondary line.

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