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

Abstract

The utility model provides a high-temperature stainless steel slag dry treatment and winnowing device, which comprises a closed cover, a movable crushing roller, a slag inlet, a crushing bed, a bottom blowing cold box, a slag receiving vehicle, 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 cover; 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 high-temperature stainless steel slag winnowing and waste heat recovery system realizes high-efficiency 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] This utility model relates to the field of high-temperature steel slag treatment technology, and more specifically, to a dry treatment and air classification device for high-temperature stainless steel slag. Background Technology

[0002] High-temperature stainless steel slag is a solid waste generated during the stainless steel smelting process, accounting for approximately 30% of the production of crude stainless steel, with annual emissions in China approaching 10 million tons. High-temperature stainless steel slag can replace some raw materials in cement and concrete, and because it contains a large amount of sensible heat, it has high heat recovery and material recycling value. In recent years, the country has increasingly demanded green and environmentally friendly development of metallurgical processes. As a byproduct of stainless steel smelting, the treatment and disposal of high-temperature stainless steel slag has become increasingly prominent. Solving the environmental pollution caused by high-temperature stainless steel slag has become a bottleneck for the development of stainless steel, seriously hindering its progress.

[0003] The efficient recovery of metallic and inorganic materials such as iron, chromium, and nickel from high-temperature stainless steel slag requires initial crushing and separation. Gravity separation and magnetic separation are then employed to achieve targeted resource utilization. Pretreatment of high-temperature stainless steel slag is a prerequisite for its crushing and magnetic separation, enabling more efficient crushing, screening, and magnetic separation.

[0004] Currently, 80% of the world's stainless steel is produced using a two-step process, with 70% of that produced through AOD converter smelting. AOD high-temperature stainless steel slag is characterized by high slag temperature, high basicity, complex phase transformations during cooling, and easy pulverization. The basicity of AOD high-temperature stainless steel slag ranges from 1.9 to 2.5, and CaO and SiO2 in the slag mainly exist in the form of 2CaO·SiO2. During the cooling process of the high-temperature steel slag from its molten state, as the temperature decreases, 2CaO·SiO2 continuously undergoes phase transformations, eventually transforming into γ-C2S at 850 ℃. With decreasing temperature, the volume of AOD high-temperature stainless steel slag expands by 11.45%, resulting in the generation of a large amount of powder. Stainless steel slag powder with a particle size ≤60 mesh can account for more than 80%, generating a large amount of dust during production, transportation, and storage, affecting the working environment. Therefore, the treatment of high-temperature stainless steel slag is a necessary step in the stainless steel production process.

[0005] Traditional high-temperature stainless steel slag treatment processes primarily employ wet methods, involving water spraying for cooling in slag pots. This method requires a large space and generates substantial amounts of polluted wastewater and dust-laden vapor, causing significant environmental pollution. Because Cr6+, a component of high-temperature stainless steel slag, is highly toxic and easily leaches out in humid environments, wet treatment produces large quantities of wastewater and sludge, severely impacting the environment and wasting the waste heat resources of the high-temperature stainless steel slag.

[0006] Stainless steel high-temperature slag has a discharge temperature as high as 1600℃, and its calorific value per ton exceeds that of 50 kg of standard coal. It contains a large amount of waste heat resources, and if all of these resources were recovered and utilized, it could generate hundreds of millions of yuan in additional economic benefits annually. Currently, waste heat recovery from high-temperature slags such as stainless steel high-temperature slag is often still in the experimental research stage, making it difficult to achieve full resource utilization of both slag and heat resources. Domestic and international attention to high-temperature stainless steel slag focuses on its secondary utilization and harmless treatment; publicly available waste heat recovery technologies for high-temperature stainless steel slag are scarce. Furthermore, waste heat recovery technologies for blast furnace slag and high-temperature steel slag cannot be directly applied to stainless steel high-temperature slag. Unlike blast furnace slag, stainless steel high-temperature slag is highly prone to pulverization at temperatures below approximately 800℃, making 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 quenching, difficult to apply to stainless steel. These processes not only fail to effectively recover waste heat but also easily lead to severe dust or sludge pollution. Utility Model Content

[0007] To address the aforementioned issues, this invention provides a high-temperature stainless steel slag dry treatment and air separation device. By replacing the wet flue gas treatment system caused by the water-cooling process with a dry dust removal method, it achieves the recovery and utilization of both "slag heat" and other resources. It features high levels of equipment automation, small footprint, low system investment, high waste heat recovery rate, and clean production.

[0008] This utility model provides a dry treatment and air classification device for high-temperature stainless steel slag, including a slag pot, a sealed hood, a movable crushing roller, a slag inlet, a crushing bed, a bottom-blown air cooling box, a slag receiving car, a slag discharge port, an air classification chamber, and a flue gas waste heat recovery system. The slag inlet is located at the upper part of the sealed hood and is used to pour the high-temperature steel slag in the slag pot onto the crushing bed through the slag inlet. The slag discharge port is located at the lower part of the sealed hood on the side away from the slag inlet. The movable crushing roller, the crushing bed, and the bottom-blown air cooling box are arranged inside the sealed hood. The bottom-blown air cooling box is located below the crushing bed. The upper side of the sealed hood is connected to the air classification chamber, which is connected to the flue gas waste heat recovery system. The slag receiving car is located below the slag discharge port. The air classification chamber is equipped with multi-stage powder bins and baffles.

[0009] In one optional embodiment, the movable crushing roller is movably disposed on the upper part of the crushing bed, and one or more bottom-blowing cold boxes are disposed on the lower part of the crushing bed. One or more cold air pipes are connected to the bottom of the bottom-blowing cold box. The cold air pipes are connected to a blower and are used to evenly distribute the cold air blown out by the blower to cool the high-temperature steel slag through the crushing bed.

[0010] In one optional embodiment, the crushing bed includes a cold slag pad and a grate. The cold slag pad is disposed on the grate to insulate the high-temperature steel slag, thereby protecting the grate from high-temperature deformation. The grate is composed of parallel grate bars arranged in an alternating pattern. The thickness of the grate is not less than 20 mm, and the gap width between the grate bars is 5-40 mm to ensure gas passage while preventing high-temperature steel slag particles from leaking into the area below the grate. The thickness of the cold slag pad is not less than 50 mm.

[0011] In one optional embodiment, the grate bar is a U-shaped open strip 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 and lower grate bar layers are composed of adjacent parallel grate bars. There are plate holes between the adjacent grate bars in the upper and lower grate bar layers. The openings of the grate bars in the upper and lower grate bar layers are arranged opposite each other. The adjacent vertical plates of the two 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 adjacent vertical plates of the two grate bars in the lower grate bar layer are located within the opening of one grate bar in the upper grate bar layer.

[0012] In an optional embodiment, the mobile crushing roller further includes crushing teeth, which are evenly arranged on the shaft of the mobile crushing roller, with 8-12 crushing teeth arranged every 360 degrees in the circumferential direction, and the included angle between two adjacent crushing teeth is 30-45 degrees; the material of the mobile crushing roller shaft and the crushing teeth is heat-resistant alloy steel, and the mobile crushing roller rotates at a certain speed to stir and crush high-temperature steel slag while realizing the slag pushing function.

[0013] In one optional embodiment, the blower delivers pressurized cold air into the sealed enclosure. Due to the significant temperature difference between the high-temperature steel slag and the cold air, the high-temperature steel slag begins to cool down, dropping to its critical self-powdering temperature of 800°C, and begins continuous self-powdering, producing fine powder with a fineness of 60-180 mesh. The self-powdered dust mixes with the heated air to form dust-laden high-temperature flue gas. As the high-temperature steel slag gradually pulverizes, the fine powder cannot adhere to it, thus preventing the high-temperature steel slag from continuing to cool down. The high-temperature steel slag is thoroughly pulverized, ultimately separating more than 95% of the fine powder smaller than 20mm from the larger fragments. The slag particles and slag blocks on the crushing bed then enter the secondary processing line. Through continuous cold air, the pulverized slag powder enters the air classifier chamber along with the high-temperature flue gas, where stainless high-temperature steel slag dust is captured under high-temperature conditions.

[0014] In one optional embodiment, the air classifier chamber collects slag powder of different particle sizes under the action of gravity to form a fine powder product of stainless high-temperature steel slag. The flue gas is discharged after waste heat recovery through the exhaust pipe. The air classifier chamber is provided with coarse slag powder bins of 5-20mm, medium slag powder bins of 2-5mm, and fine slag powder bins of less than 2mm in sequence along the flue gas flow direction. One or more baffles are provided above the coarse slag powder bins and / or the medium slag powder bins and / or the fine slag powder bins. The baffles are inclined at 5-85 degrees clockwise to change the wind direction in a local area of ​​the air classifier chamber, so as to avoid the wind being directly discharged from the air classifier equipment and the occurrence of local turbulence.

[0015] In one optional embodiment, the bottom of the coarse slag powder bin, the medium slag powder bin, and the fine slag powder bin of the air classifier are respectively provided with a coarse slag powder outlet, a medium slag powder outlet, and a fine slag powder outlet. Each slag powder outlet is equipped with a controllable valve, and each controllable valve has two valve baffles. The size of the outlet area is adjusted by changing the angle between the two valve baffles to control the rate at which the slag powder leaves the air classifier.

[0016] In one optional embodiment, the flue gas waste heat recovery system includes an induced draft duct, a flue gas boiler, a bag filter, 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 separation chamber, and the other end is connected to the flue gas boiler.

[0017] In one optional embodiment, the heat from the high-temperature flue gas in the flue gas boiler is exchanged with the working fluid water that performs work in the flue gas boiler, completing the "gas-liquid" heat exchange, which raises the temperature of the working fluid water in the flue gas boiler and forms high-quality saturated steam. After the temperature drops, the gas that still contains dust enters the bag filter to collect the dust again. The bag filter is connected to the chimney through an induced draft fan to discharge the dust-collected flue gas. The sealed cover, induced draft pipe, and flue gas boiler are insulated with inorganic insulation cotton.

[0018] This invention uses a crushing bed as the carrier for treating high-temperature steel slag. A crusher efficiently crushes the high-temperature steel slag, a bottom-blown cooling box cools it, and an air classifier collects the stainless steel slag powder. A heat exchanger and generator recover the waste heat from the high-temperature steel slag for power generation. The high-temperature steel slag is poured into the crushing bed, while cold air is simultaneously introduced from the bottom to cool and solidify it. The crusher rotates at a certain speed, simultaneously crushing the high-temperature steel slag and also acting as a slag pusher. At the same time, the high-temperature steel slag powder is air-classified for subsequent use.

[0019] The slag powder in the air separation chamber of this invention has a low metal content and is generally less than 20mm in size, making it suitable for use in the production of cement, microcrystalline glass, and road materials, or as a raw material for soil conditioners or fertilizers. A flue gas boiler is used to recover waste heat from the high-temperature flue gas to generate high-quality steam, which can be used for drying, heating, and power generation. This equipment has a high crushing capacity, significantly improving the efficiency of high-temperature steel slag processing. Simultaneously, the high-temperature flue gas obtained through air-cooled heat exchange during the crushing process can be used for waste heat recovery and power generation.

[0020] This invention can achieve a power generation of 10-20 kWh per ton of slag, with significant economic benefits from waste heat recovery. After crushing, the proportion of high-temperature steel slag <50mm reaches over 80%, significantly improving the pulverization rate of high-temperature steel slag. After heat exchange, the high-temperature flue gas is cooled and then discharged in an organized manner via a dust collector, with a dust emission concentration below 10 mg / m³. 3 .

[0021] This invention achieves efficient crushing, slag powder air separation, and waste heat recovery of high-temperature steel slag through both equipment and method. It eliminates the need for a water-cooling system 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. It has the technical advantages of convenient production operation, high degree of automation, small footprint, good airtightness, low system investment, and ultra-clean emissions. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 A schematic diagram of the overall operation of a high-temperature stainless steel slag dry treatment and air separation device provided by this utility model.

[0024] Figure 2 A schematic diagram of a crushing bed structure for a high-temperature stainless steel slag dry treatment and air separation device provided by this utility model.

[0025] Figure 3 The present invention provides an overall flow chart of a dry treatment and air classification method for high-temperature stainless steel slag.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1-Slag pot, 2-Sealed cover, 3-Moving crushing roller, 4-Slag inlet, 5-Cold slag pad, 6-Grate plate, 7-Crushing bed, 8-Blower, 9-Cold air duct, 10-Bottom-blown cold air box, 11-Slag receiving car, 12-Slag discharge port, 13-Controllable valve, 14-Induced draft pipe, 15-Flue gas boiler, 16-Bag dust collector, 17-Induced draft fan, 18-Chimney, 19-Slag discharge port, 20-High temperature steel slag, 21-Wind baffle, 22-Crushing teeth, 23-Grate bar, 24-Panel hole. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0029] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] See appendix Figure 1-2 This utility model provides a high-temperature stainless steel slag dry treatment and air classification device, including a slag tank 1, a sealed cover 2, a movable crushing roller 3, a slag inlet 4, a crushing bed 7, a bottom-blown air cooling box 10, a slag receiving car 11, an air classification chamber 12, and a flue gas waste heat recovery system. The movable crushing roller 3, the crushing bed 7, and the bottom-blown air cooling box 10 are installed inside the sealed cover 2. The upper side of the sealed cover 2 is connected to the air classification chamber 12, and the air classification chamber 12 is connected to the flue gas waste heat recovery system. The slag inlet 4 is closable and located at the top of the sealed cover 2. The slag receiving car 11 is located at the bottom of the sealed cover 2. The air classification chamber 12 is equipped with multi-stage powder bins and wind baffles 21.

[0031] Furthermore, it also includes a slag pot 1, which is located above the sealed cover 3 and can move back and forth under the action of the crane. It is used to pour the high-temperature steel slag 5 in the slag pot 1 into the cold slag pad layer 5 of the crushing bed 7 through the slag discharge port 4.

[0032] Furthermore, the movable crushing roller 3 is movably disposed on the upper part of the crushing bed 7, and one or more bottom-blowing cold boxes 10 are disposed on the lower part of the crushing bed 7. One or more cold air pipes 9 are connected to the bottom of the bottom-blowing cold box 10, and the cold air pipes 9 are connected to the blower 8.

[0033] Furthermore, the crushing bed 7 includes a cold slag pad 5 and a grate plate 6. The cold slag pad 5 is disposed on the grate plate 6. The cold slag pad 5 is disposed above the grate plate 5 to insulate the high-temperature steel slag 20 and protect the grate plate 6 from high-temperature deformation. While ensuring the passage of gas, it prevents high-temperature steel slag particles from leaking into the area below the grate plate. The grate plate 6 is composed of parallel grate bars 23 arranged in an alternating pattern.

[0034] Furthermore, the grate bar 23 is a U-shaped open strip 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 and lower grate bar layers are composed of adjacent parallel grate bars 23. Each adjacent grate bar 23 in the upper and lower grate bar layers has a plate hole 24. The openings of the grate bars 23 in the upper and lower grate bar layers are arranged opposite 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. 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.

[0035] Furthermore, the movable crushing roller 3 also includes crushing teeth 22, which are evenly arranged on the shaft of the movable crushing roller 3. There are 8-12 crushing teeth 22 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.

[0036] Furthermore, the air classifier chamber 12 is provided with coarse slag powder bins, medium slag powder bins, and fine slag powder bins connected in sequence along the flue gas flow direction. One or more baffles 21 are provided above the coarse slag powder bins and / or the medium slag powder bins and / or the fine slag powder bins, and the baffles 21 are inclined clockwise at 5-85 degrees. The baffles 21 are used to change the wind direction in a local area of ​​the air classifier chamber 12, preventing the wind from being directly discharged from the air classifier and preventing local turbulence.

[0037] Furthermore, the bottom of the coarse slag powder bin, the medium slag powder bin, and the fine slag powder bin of the air classifier 12 are respectively provided with coarse slag powder outlet, medium slag powder outlet, and fine slag powder outlet. Each slag powder outlet is equipped with a controllable valve 13. Each controllable valve 13 has two valve baffles. By changing the angle between the two valve baffles, the size of the outlet area is adjusted to control the rate at which the slag powder leaves the air classifier 12.

[0038] Furthermore, the air classifier 12 is used to classify and store the slag powder generated during the air cooling process of high-temperature stainless steel slag. The slag powder in the air classifier has a low metal content and is generally less than 20mm in size. It can be used to make cement, microcrystalline glass and road materials, or as a raw material for soil conditioners or fertilizers.

[0039] Furthermore, 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 connected in sequence. 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.

[0040] Furthermore, the sealed enclosure 2, the exhaust pipe 14, and the flue gas boiler 15 are insulated with inorganic insulation cotton.

[0041] 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.

[0042] Furthermore, the thickness of the grate plate 6 is not less than 20mm, the gap width of the plate hole 24 between the grate bars 23 is 5-40mm, and the thickness of the cold slag pad layer 5 is not less than 50mm.

[0043] Furthermore, a slag discharge port 19 is provided on the side of the crushing bed 7 away from the slag inlet 4. The slag receiving car 11 is movably located at the bottom of the slag discharge port 19. The slag receiving car 11 is located below the slag discharge port 19 and is used to transport the remaining slag particles and slag blocks on the crushing bed 7 after air classification to the secondary processing line.

[0044] Furthermore, the slag inlet 4 is located above the sealed cover 2, and is used to pour the high-temperature steel slag 20 in the slag pot 1 into the cold slag pad layer 5 of the crushing bed 7 through the slag inlet 4.

[0045] 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 speed, crushing the high-temperature steel slag while also pushing the slag.

[0046] Furthermore, the bottom-blowing cold box 10 is located below the crushing bed 7 to evenly distribute the cold air blown out by the blower 8, and cool the high-temperature steel slag through the grate plate 6 and the cold slag pad layer.

[0047] Furthermore, the blower 8 delivers cold air with a certain pressure into the sealed hood 2. Due to the huge temperature difference between the high-temperature steel slag and the cold air, the high-temperature steel slag begins to cool down to the critical temperature of 800℃ for self-powdering and begins to continuously self-powder, producing fine powder with a fineness ranging from 60 to 180 mesh. The self-powdered dust mixes with the heated air to form dust-laden high-temperature flue gas.

[0048] Furthermore, as the high-temperature steel slag 20 gradually pulverizes, the fine powder cannot adhere to it and cannot prevent it from cooling down further. Therefore, the high-temperature steel slag is completely pulverized, ultimately separating more than 95% of the fine powder smaller than 20mm from the larger fragments. At the same time, under the suction of the induced draft fan 17, the dust-laden high-temperature flue gas is sent into the air separation chamber 12 for the collection of stainless high-temperature steel slag dust under high-temperature conditions.

[0049] Furthermore, the high-temperature stainless steel slag is continuously cooled by cold air, and the pulverized slag powder enters the air classifier chamber 12 along with the high-temperature flue gas. Under the action of gravity, slag powder of different particle sizes is captured to form a fine powder product of high-temperature stainless steel slag. The flue gas is discharged after waste heat recovery through the exhaust pipe.

[0050] Furthermore, the air separation chamber is equipped with coarse slag powder bins of 5-20mm, medium slag powder bins of 2-5mm, and fine slag powder bins of <2mm, which can be used to make cement, microcrystalline glass and road materials, or as raw materials for soil conditioners or fertilizers.

[0051] Furthermore, within the flue gas boiler 15, the heat from the high-temperature flue gas is exchanged with the working fluid water that performs work within the flue gas boiler 15, completing the "gas-liquid" heat exchange. This causes the temperature of the working fluid water within the flue gas boiler 15 to rise, forming high-quality saturated steam that can be used for drying, heating, power generation, etc., while the flue gas temperature decreases.

[0052] Furthermore, the flue gas boiler 15 is also connected to a bag filter 16 through a pipe. The gas that still contains dust after the temperature drops enters the bag filter 16 to collect dust again. The bag filter 16 is connected to a chimney 18 through an induced draft fan 17 to discharge the dust-collected flue gas.

[0053] Furthermore, the inner diameter of the slag inlet 4 is not less than 2000mm. The slag inlet 4 is opened by a pulley for slag feeding. The moving crushing roller 3 pushes the remaining slag blocks and particles on the air-separated crushing bed 7 to the slag discharge port 19 for slag discharge. The slag discharge port 19 is opened by a pulley for slag discharge to the slag receiving car 11.

[0054] Furthermore, the grate plate 6 has a thickness of not less than 20mm and is composed of interlocking grate bars 23. Plate holes 24 are provided between the grate bars 23, and the gap width of the plate holes 24 is 5-40mm to ensure gas passage while preventing high-temperature steel slag particles from leaking into the bottom of the grate plate. A cold slag pad layer 5 is provided above the grate plate 6 to insulate the high-temperature steel slag 20 and protect the grate plate 6 from high-temperature deformation. The thickness of the cold slag pad layer 5 is not less than 50mm.

[0055] See appendix Figure 3 This utility model also provides a method for dry treatment and air classification of high-temperature stainless steel slag, which includes the following steps:

[0056] Step S1. High-temperature steel slag is fed in. The slag discharge port 4 on the sealed cover 2 is opened and the slag discharge port 11 is closed. The slag pot 1 containing high-temperature steel slag 20 is hoisted by a crane and dumped onto the crushing bed 7. The high-temperature steel slag 20 falls onto the cold slag pad layer 5.

[0057] Step S2. High-temperature steel slag crushing and convective heat exchange: Start blower 8 to blow cold air through cold air pipe 9 into bottom blowing cold air box 10, and then through grate plate 6 and cold slag pad 5 to air-cool the high-temperature steel slag 20; at the same time, start moving crushing roller 3, moving crushing roller 3 reciprocates, and through crushing teeth 22 on moving crushing roller 3, stir and crush the high-temperature steel slag 7, solidify it into slag blocks and slag particles; bottom blowing cold air and high-temperature steel slag 20 undergo convective heat exchange during the stirring and crushing process;

[0058] Step S3. High-temperature steel slag is pulverized to form high-temperature dust-laden hot flue gas and air-classified slag powder. After the stainless high-temperature steel slag is solidified to a certain particle size through continuous cold air for a certain period of time, the stainless high-temperature steel slag drops to the self-pulverization critical temperature of 800℃ and begins continuous self-pulverization. The pulverized slag powder mixes with the heated air after heat exchange to form high-temperature dust-laden hot flue gas, which enters the air-classification chamber 12 and enters the slag powder bins of different particle sizes for separation under the action of gravity.

[0059] Step S4. High-temperature waste heat recovery of flue gas: While the flue gas is being cooled by blower, 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 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 waste heat. The flue gas cooled by the flue gas boiler 15 is discharged to the outside through the dust collector 16, induced draft fan 17 and chimney 18 of the waste heat recovery system.

[0060] Furthermore, in step S3, the stainless high-temperature steel slag 20 is cooled and gradually pulverized under the action of continuous cold air. 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 smaller than 20mm from the larger fragments. The moving crushing roller 3 pushes the remaining slag blocks and slag particles on the air-classified crushing bed 7 to the slag discharge port 19 for slag discharge. The slag discharge port 19 is opened by a pulley to discharge slag to the slag receiving car 11. The slag receiving car 11 transports the slag particles and slag blocks to the secondary line.

[0061] In one embodiment of this utility model, the slag dumping time of a single slag pot 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 / minute. The processing rate of high-temperature steel slag can be increased by increasing the rotation speed of the moving crushing roller 3, and vice versa.

[0062] In one embodiment of this invention, the air volume for cooling high-temperature steel slag is 1000-4000 m³ / h.3 / ton of stainless high-temperature steel slag can be cooled and the slag powder can be air-classified by increasing the air volume, thus controlling the particle size distribution of the slag powder in the air-classification chamber to become larger. Conversely, the cooling rate of the stainless high-temperature steel slag can be reduced to control the particle size distribution of the slag powder in the air-classification chamber to become smaller.

[0063] In one embodiment of this invention, the temperature of the slag blocks and particles discharged from the slag discharge port 12 is controlled at 100-200℃. After crushing, more than 80% of the remaining high-temperature stainless steel slag blocks and particles have a particle size of <50mm.

[0064] In one embodiment of this utility model, the blower 8 provides ambient temperature air as the cooling gas for the high-temperature steel slag. The high-temperature flue gas obtained by cooling and heat exchange with the high-temperature steel slag 20 has a temperature of 250-500℃. The high-temperature flue gas is cooled to below 150℃ by heat exchanger 15, and then discharged in an organized manner through bag filter 16, induced draft fan 17, and chimney 18. The dust concentration of the discharged flue gas is less than 10mg / m³. 3 The saturated steam obtained from the high-temperature flue gas after heat exchange in heat exchanger 15 can be used for drying, heating, power generation, etc. If used for power generation, the power generation per ton of high-temperature steel slag is 10-20 kWh.

[0065] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0066] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to 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 classification device, comprising a slag pot (1), a sealed hood (2), a moving crushing roller (3), a slag inlet (4), a crushing bed (7), a bottom-blown air cooling box (10), a slag receiving car (11), a slag discharge port (19), an air classification chamber (12), and a flue gas waste heat recovery system, characterized in that, The slag inlet (4) is closable and located on the upper part of the sealed cover (2) for pouring the high-temperature steel slag (20) in the slag pot (1) into the crushing bed (7) through the slag inlet (4). The slag discharge port (19) is located on the lower part of the sealed cover (2) away from the slag inlet (4). The sealed cover (2) is equipped with the moving crushing roller (3), the crushing bed (7), and the bottom blowing air cooling box (10). The bottom blowing air cooling box (10) is located below the crushing bed (7). The upper side of the sealed cover (2) is connected to the air classifier (12). The air classifier (12) is connected to the flue gas waste heat recovery system. The slag receiving car (11) is located below the slag discharge port (19). The air classifier (12) is equipped with multi-stage powder bins and baffles (21). The sealed cover (2) is insulated with inorganic insulation cotton.

2. The high temperature stainless steel slag dry processing and air classification device of claim 1, wherein, The movable crushing roller (3) is movably disposed on the upper part of the crushing bed (7), and one or more bottom-blowing cold boxes (10) are disposed on the lower part of the crushing bed (7). One or more cold air pipes (9) are connected to the bottom of the bottom-blowing cold box (10). 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 out by the blower (8) and cool the high-temperature steel slag through the crushing bed (7).

3. The high temperature stainless steel slag dry processing and air classification device of claim 2, wherein, The crushing bed (7) includes a cold slag pad (5) and a grate (6). The cold slag pad (5) is placed on the grate (6) to insulate the high-temperature steel slag (20) and thus protect the grate (6) from high-temperature deformation. The grate (6) is composed of parallel grate bars (23) arranged in an alternating pattern. The thickness of the grate (6) is not less than 20 mm. The gap width between the grate bars (23) is 5-40 mm to ensure gas passage while preventing high-temperature steel slag particles from leaking into the grate. The thickness of the cold slag pad (5) is not less than 50 mm.

4. The high temperature stainless steel slag dry processing and air classification device of claim 3, wherein, The grate bar (23) is a U-shaped open strip 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 and lower grate bar layers are composed of adjacent parallel grate bars (23). There are plate holes (24) between the adjacent grate bars (23) of the upper and lower grate bar layers. The openings of the grate bars (23) of the upper and lower grate bar layers are arranged opposite each other. The adjacent vertical plates of the two grate bars (23) of the upper grate bar layer are located in the opening of one grate bar (23) of the lower grate bar layer. The adjacent vertical plates of the two grate bars (23) of the lower grate bar layer are located in the opening of one grate bar (23) of the upper grate bar layer.

5. The high temperature stainless steel slag dry processing and air classification device of claim 2, wherein, The mobile crushing roller (3) also includes crushing teeth (22), which are evenly arranged on the shaft of the mobile crushing roller (3). There are 8-12 crushing teeth (22) arranged every 360 degrees in the circumferential direction, and the included angle between two adjacent crushing teeth (22) is 30-45 degrees. The material of the shaft of the mobile crushing roller (3) and the crushing teeth (22) is heat-resistant alloy steel. The mobile crushing roller (3) rotates at a certain speed to stir and crush the high-temperature steel slag (20) while pushing the slag.

6. The high temperature stainless steel slag dry processing and air classification device of claim 3, wherein, The blower (8) delivers cold air with a certain pressure into the sealed hood (2). Due to the huge temperature difference between the high-temperature steel slag (20) and the cold air, the high-temperature steel slag itself begins to cool down to the critical temperature of 800℃ and begins to continuously self-powder, producing fine powder with a fineness of 60 to 180 mesh. The self-powdered dust mixes with the heated air to form dust-laden high-temperature flue gas. As the high-temperature steel slag (20) gradually pulverizes, 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 pulverized, and finally more than 95% of the fine powder below 20mm 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 pulverized slag powder enters the air classifier (12) with the high-temperature flue gas and is used for stainless high-temperature steel slag dust collection under high temperature conditions.

7. The high temperature stainless steel slag dry processing and air classification device of claim 1, wherein, The air separation chamber (12) captures slag powder of different particle sizes under the action of gravity to form stainless high-temperature steel slag fine powder products. The flue gas is discharged after the waste heat is recovered through the exhaust pipe. The air separation chamber (12) is provided with coarse slag powder bins of 5-20mm, medium slag powder bins of 2-5mm and fine slag powder bins of less than 2mm in sequence along the flue gas flow direction. One or more baffles (21) are provided on the upper part of the coarse slag powder bins and / or medium slag powder bins and / or fine slag powder bins. The baffles (21) are inclined at 5-85 degrees clockwise to change the wind direction in a local area of ​​the air separation chamber (12) to avoid the wind being directly discharged from the air separation equipment and the occurrence of local turbulence.

8. The high temperature stainless steel slag dry processing and air classification device of claim 6, wherein, The bottom of the coarse slag powder bin, the medium slag powder bin, and the fine slag powder bin of the air classifier (12) are respectively provided with coarse slag powder outlet, medium slag powder outlet, and fine slag powder outlet. Each slag powder outlet is equipped with a controllable valve (13). Each controllable valve (13) has two valve baffles. The size of the outlet area is adjusted by changing the angle between the two valve baffles to control the rate at which the slag powder leaves the air classifier (12).

9. The high temperature stainless steel slag dry processing and air classification device of claim 1, wherein, 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) connected in sequence. 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).

10. The high temperature stainless steel slag dry processing and air classification device of claim 9, wherein, Inside the flue gas boiler (15), the heat in the high-temperature flue gas is exchanged with the working fluid water inside the flue gas boiler (15) to complete the "gas-liquid" heat exchange, so that the temperature of the working fluid water inside the flue gas boiler (15) rises and forms high-quality saturated steam. After the temperature drops, the gas that still contains dust enters the bag filter (16) to collect dust again. The bag filter (16) is connected to the chimney (18) through the induced draft fan (17) to discharge the dust-removed flue gas. The induced draft pipe (14) and the flue gas boiler (15) are insulated with inorganic insulation cotton.

Images