Aluminum ash rotary kiln and polyaluminum chloride production process

Abstract

The application discloses an aluminum ash rotary kiln and a polyaluminum chloride production process, and relates to the technical field of rotary kilns. The aluminum ash rotary kiln comprises a rotary kiln main body, and the rotary kiln main body comprises a kiln body, a kiln tail, a kiln head and a spiral conveyor used for feeding into the rotary kiln main body. When the raw materials are calcined in the rotary kiln, the kiln body can drive the raw materials to be turned over when the kiln body rotates, and the raw materials fall on the first filter plate under the action of gravity. At the same time, the second filter plate can be driven to move back and forth by a driving mechanism, and a plurality of rolling mills can be driven to roll back and forth by the first fixing frame and the rotating shaft. At this time, the raw materials on the first filter plate can be laid flat, and the caked raw materials can be crushed by rolling at the same time. The crushed and laid flat raw materials can fall into the kiln body again through the first filter plate, so that the raw materials at the bottom of the kiln body are uniformly distributed, caking is avoided, uniform calcination is ensured, and the efficiency and quality of high-temperature calcination are improved.

Description

Technical Field

[0001] This invention relates to the field of rotary kiln technology, specifically to an aluminum ash rotary kiln and a process for producing polyaluminum chloride. Background Technology

[0002] In the production of polyaluminum chloride, aluminum ash is used as raw material. During the production process, a rotary kiln is used to calcine the mixture of aluminum ash (high alumina ash) and limestone after raw material homogenization, drying, and grinding. This causes a series of physical and chemical changes in the raw materials, thereby generating clinker of the target product.

[0003] However, in existing rotary kilns, raw materials are transported to the kiln body via a screw conveyor at the kiln tail for high-temperature calcination. As the kiln body rotates, the raw materials are tumbled and gradually transported to the discharge port at the kiln head. The raw materials tend to accumulate at the bottom of the kiln body, resulting in uneven distribution and uneven calcination. Furthermore, the raw materials are prone to agglomeration within the kiln body, affecting the quality of calcium aluminate powder and consequently impacting the efficiency and quality of polyaluminum chloride production. Summary of the Invention

[0004] The purpose of this invention is to provide an aluminum ash rotary kiln that can spread raw materials evenly and crush agglomerated raw materials, so as to solve the problems mentioned in the background art, such as the raw materials easily accumulating at the bottom of the kiln body, resulting in uneven distribution, uneven calcination, and the raw materials easily agglomerating in the kiln body.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a rotary kiln for aluminum ash, comprising a rotary kiln body, the rotary kiln body including a kiln body, a kiln tail, a kiln head, and a screw conveyor for feeding material into the rotary kiln body; the kiln body including an inner lining; the screw conveyor including a cylinder, a hopper, a geared motor, a rotating rod, and screw blades; the rotary kiln body further including a crushing and spreading mechanism disposed within the kiln body for crushing and spreading the raw material; the crushing and spreading mechanism including a first filter plate connected to the kiln tail, a second filter plate moving within the kiln body, and a driving mechanism for driving the second filter plate to move; the first and second filter plates are inclined downwards; the crushing and spreading mechanism further includes multiple rolling rollers above the first filter plate, multiple first fixed frames connected to the second filter plate, and a rotating shaft connecting the rolling rollers and the first fixed frames.

[0006] Preferably, the rotary kiln body further includes a secondary crushing mechanism disposed below the first filter plate and the second filter plate; the secondary crushing mechanism includes a first friction plate connected to the first filter plate, a second friction plate connected to the second filter plate, and a protrusion connected to the opposite sidewalls of the first friction plate and the second friction plate; a conical groove is formed between the second friction plate and the first friction plate.

[0007] Preferably, the driving mechanism includes a first movable plate disposed inside the kiln body, a first connecting plate connected between the first movable plate and the second filter plate, and two first guide rods connected to the first movable plate; the first guide rods are disposed through the kiln tail; the driving mechanism also includes a U-shaped plate connected to the first guide rods, a spring connected between the U-shaped plate and the kiln tail, and a pushing mechanism for moving the U-shaped plate; the spring is sleeved on the side wall of the first guide rod.

[0008] Preferably, the drive mechanism includes a driven bevel gear, a cam, and a rotating shaft connected between the driven bevel gear and the driven bevel gear; the drive mechanism also includes a driving bevel gear connected to the rotating rod and a first connecting block connected between the rotating shaft and the cylinder.

[0009] Preferably, the rotary kiln body further includes a pre-crushing mechanism for pre-crushing the raw materials input into the cylinder; the pre-crushing mechanism includes a preheating box connected to the cylinder, a filter screen connected to the preheating box, and a discharge port disposed at the bottom of the preheating box; the pre-crushing mechanism also includes an extrusion plate disposed in the preheating box and a lifting mechanism for driving the extrusion plate to move up and down; the extrusion plate includes a baffle plate penetrating the top of the preheating box.

[0010] Preferably, the lifting mechanism includes a connecting rod rotatably connected to the baffle, a second connecting plate connected to the first moving plate, and a support connected between the connecting rod and the second connecting plate; the lifting mechanism also includes a second connecting block connected to the baffle and a first spring telescopic rod connected between the second connecting block and the preheating box.

[0011] Preferably, the pre-crushing mechanism further includes a metering mechanism for metering the raw material discharged from the outlet into the kiln body; the metering mechanism includes a sealing plate connected to the preheating box, a second movable plate connected to the second connecting plate, and a first metering groove and a second metering groove opened on the second movable plate; the first metering groove and the second metering groove are disposed through the second movable plate; the sealing plate can perform movable sealing on the bottom of the first metering groove and the second metering groove.

[0012] Preferably, the rotary kiln body further includes a pushing assembly disposed on the inner wall of the kiln body for pushing the raw material to rotate with the kiln body; the pushing assembly includes multiple strip openings on the inner lining, a pushing plate sliding within the strip openings, and an inclined surface disposed on the pushing plate; the pushing assembly also includes a second guide rod connected to the pushing plate, a second fixing frame connected to the outer wall of the kiln body, and a second spring telescopic rod connected between the second guide rod and the second fixing frame; the second guide rod is disposed through the kiln body.

[0013] Preferably, the rotary kiln body further includes a cleaning mechanism disposed within the kiln body for scraping and cleaning the rings on the lining; the cleaning mechanism includes multiple scrapers and a support plate connected between the scrapers and the first moving plate; the scrapers include stepped blocks disposed on both sides.

[0014] A process for producing polyaluminum chloride includes the following steps:

[0015] S1: Aluminum ash grading and pretreatment: Aluminum ash is screened in multiple stages by a professional mill. The high-purity aluminum ash separated is sent to an electric melting furnace to smelt aluminum blocks for sale. The remaining aluminum ash is precisely graded into low-aluminum ash (sealed for later use) and high-aluminum ash (used for subsequent calcination) according to the aluminum content. During the screening process, a bag filter dust collector is used to collect dust to reduce dust pollution.

[0016] S2: Raw material crushing and dust removal: Limestone and high-alumina limestone are crushed separately by jaw crushers, with the crushing particle size controlled at 20-50mm; a bag filter dust removal system is used throughout the crushing process to efficiently collect the generated dust, with a dust recovery rate of no less than 98%, to prevent dust leakage.

[0017] S3: Raw material homogenization treatment: The crushed limestone, high-alumina limestone and dust recovered from bag filter dust collection in each stage are sent together into the raw material homogenization silo. The raw material components are uniformly mixed by the air stirring device in the silo, and the homogenization coefficient is controlled within 1.5 to ensure the stability of the subsequent calcination reaction.

[0018] S4: Drying and Exhaust Gas Treatment: The homogenized raw material is fed into a rotary dryer for drying. The drying temperature is controlled at 120-150℃ to remove free moisture from the raw material to below 5%. Dust, SO2, and NO generated during the drying process are treated. x The exhaust gas is treated by a bag filter dust collector and an integrated desulfurization and denitrification device, and is discharged after meeting the standards. The exhaust gas treatment efficiency meets the GB16297-1996 standard.

[0019] S5: Fine grinding of raw materials: The dried raw materials are fed into a ball mill for fine grinding. After grinding, the fineness of the raw materials is controlled to have a sieve residue of ≤10% on an 80μm square hole sieve. The dust generated during the grinding process is collected in real time by a bag dust collection system. The collected dust is returned to the raw material homogenization stage for recycling, thus realizing resource recovery.

[0020] S6: Rotary Kiln Calcination Operation: The ground raw material is fed into the aluminum ash rotary kiln via a screw conveyor. At the same time, coal crushed to a particle size ≤10mm (treated by bag filter dust removal) is fed into the kiln body (101) through the burner at the kiln head 103 as fuel and burned in the kiln head 103 area to provide a high-temperature heat source for calcination. The calcination temperature is controlled at 1200-1400℃. The residence time of the raw material in the kiln body (101) is 30-45 minutes. During calcination, the rotation of the kiln body 101 can cause the raw material to tumble and fall onto the first filter plate 100 under the action of gravity. At the same time, the second filter plate 1002 can be driven to move back and forth through the drive mechanism, and multiple rolling rollers 1005 can be driven to roll back and forth through the first fixed frame 1003 and the rotating shaft 1004. At this time, the raw material on the first filter plate 1001 can be spread flat, and the agglomerated raw material can be crushed. The crushed and spread raw material can fall back into the kiln body 101 through the first filter plate 1001, ensuring that the raw material at the bottom of the kiln body (101) is evenly distributed, avoiding agglomeration, ensuring uniform calcination, and improving the efficiency and quality of high-temperature calcination.

[0021] S7: Clinker Processing and Dust Collection: The clinker calcined in the rotary kiln is temporarily stored in the clinker silo, and then further ground in a clinker grinding mill to a fineness ≥325 mesh to obtain calcium aluminate powder. Baghouse dust collectors are used to collect dust during the grinding process, with a dust recovery rate of 100%. The effective alumina content of the finished calcium aluminate powder is ≥50%.

[0022] S8: Low-alumina ash acidolysis reaction: Send the prepared low-alumina ash into a corrosion-resistant reaction tank, add industrial hydrochloric acid with a concentration of 20-25% at a liquid-to-solid ratio of 3:1, control the reaction temperature at 80-90℃, the stirring rate at 60r / min, and the reaction time at 2-3 hours to fully convert aluminum elements into aluminum chloride solution.

[0023] S9: Pressure Filtration Separation and Purification: After the acid hydrolysis reaction is completed, the slurry is sent to a plate and frame filter press for pressure filtration. The filtration pressure is controlled at 0.6-0.8 MPa to separate the filter residue (which is discharged after harmless treatment) and the clarified filtrate. The Al2O3 content of the filtrate is controlled at 8-10%.

[0024] S10: Compounding and performance adjustment: Pump the clarified filtrate into the compounding tank, add the finished calcium aluminate powder in proportion, adjust the pH of the slurry to 3.5-4.5, stir and compound at 50-60℃ for 1-1.5 hours to optimize the basicity (controlled at 40-90%) and flocculation performance of polyaluminum chloride.

[0025] S11: Finished product separation and refining: The compounded slurry is sent to a sedimentation tank for natural sedimentation (sedimentation time ≥ 8 hours) or is filtered again by a filter press to remove impurities and filter residue, and obtain liquid polyaluminum chloride product with a purity ≥ 98%. The filter residue can be recycled as building auxiliary material after drying.

[0026] S12: Finished Product Forming and Storage: Liquid polyaluminum chloride can be directly packaged for export; if solid products are required, the liquid polyaluminum chloride is sent to a spray drying tower and dried and formed under hot air conditions of 200-220℃ to obtain solid polyaluminum chloride particles (particle size 0.5-1.5mm). After the finished product passes inspection, it is sealed and packaged and stored in a dry and ventilated warehouse to avoid moisture absorption and deterioration.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] This rotary kiln for aluminum ash production and the process for producing polyaluminum chloride utilizes a crushing and spreading mechanism. When the raw material is calcined in the rotary kiln, the kiln's rotation causes the material to tumble and fall onto the first filter plate under gravity. Simultaneously, a drive mechanism moves the second filter plate back and forth, while a first fixed frame and a rotating shaft drive multiple rolling rollers to roll back and forth. This process spreads the raw material on the first filter plate evenly and crushes any clumps. The crushed and spread material then falls back into the kiln through the first filter plate, ensuring uniform distribution of the material at the bottom of the kiln, preventing clumping, guaranteeing uniform calcination, and improving the efficiency and quality of high-temperature calcination. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0030] Figure 2 This is a partial cross-sectional view of the kiln body and kiln head in this invention.

[0031] Figure 3 This is a partial cross-sectional view of the kiln body, hopper, and cylinder in this invention.

[0032] Figure 4 This is a schematic diagram of the crushing and spreading mechanism in this invention;

[0033] Figure 5 This is a schematic diagram of the secondary crushing mechanism in this invention;

[0034] Figure 6 This is a schematic diagram of the lifting mechanism and the metering mechanism in this invention;

[0035] Figure 7 This is a partial cross-sectional view of the preheating box and the discharge port in this invention.

[0036] Figure 8 This is a schematic diagram of the cleaning mechanism in this invention;

[0037] Figure 9 This is a schematic diagram of the structure of the driving component in this invention;

[0038] Figure 10 This is a schematic diagram of the drive mechanism in this invention.

[0039] In the diagram: 101, kiln body; 102, kiln tail; 103, kiln head; 104, lining; 105, cylinder; 106, hopper; 107, geared motor; 108, rotating rod; 109, spiral blade; 201, second friction plate; 202, first friction plate; 203, protruding strip; 301, first moving plate; 302, first connecting plate; 303, first guide rod; 304, spring; 305, U-shaped plate; 401, driving bevel gear; 402, first connecting block; 403, driven bevel gear; 404, rotating shaft; 405, cam; 501, preheating box; 502, filter screen; 503, extrusion plate; 504, discharge port. 505. Baffle; 601. Second connecting plate; 602. Second moving plate; 603. First metering groove; 604. Second metering groove; 605. Sealing plate; 701. Support; 702. Connecting rod; 703. Second connecting block; 704. First spring telescopic rod; 801. Support plate; 802. Scraper; 803. Step block; 901. Strip opening; 902. Push plate; 903. Inclined surface; 904. Second guide rod; 905. Second fixed frame; 906. Second spring telescopic rod; 1001. First filter plate; 1002. Second filter plate; 1003. First fixed frame; 1004. Rotating shaft; 1005. Roller. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0041] Please see Figures 1-10This invention provides a rotary kiln for aluminum ash, comprising a rotary kiln body, which includes a kiln body 101, a kiln tail 102, a kiln head 103, and a screw conveyor for feeding material into the rotary kiln body. The kiln body 101 includes a lining 104, and the screw conveyor includes a cylinder 105, a hopper 106, a geared motor 107, a rotating rod 108, and screw blades 109. The kiln head 103 is provided with a discharge port and a burner for feeding fuel. These are all known technologies in this technical field. Without going into detail, the rotary kiln body also includes a crushing and spreading mechanism disposed within the kiln body 101 for crushing and spreading the raw materials; the crushing and spreading mechanism includes a first filter plate 1001 connected to the kiln tail 102, a second filter plate 1002 moving within the kiln body 101, and a drive mechanism for driving the second filter plate 1002 to move; the first filter plate 1001 and the second filter plate 1002 are arranged inclined downwards; the crushing and spreading mechanism also includes multiple milling machines located above the first filter plate 1001. The components inside the kiln body 101, including the pressure roller 1005, multiple first fixed frames 1003 connected to the second filter plate 1002, and the rotating shaft 1004 connecting the pressure roller 1005 and the first fixed frames 1003, are all made of high-temperature resistant materials. When the raw material is calcined in the rotary kiln, the rotation of the kiln body 101 can cause the raw material to tumble and fall onto the first filter plate 1001 under the action of gravity. At the same time, the second filter plate 1002 can be driven to move back and forth through the drive mechanism, and multiple pressure rollers 1005 can be driven to roll back and forth through the first fixed frame 1003 and the rotating shaft 1004. At this time, the raw material on the first filter plate 1001 can be spread flat, and the lumpy raw material can be crushed and pulverized. The crushed and spread raw material can fall back into the kiln body 101 through the first filter plate 1001, ensuring that the raw material is evenly distributed at the bottom of the kiln body (101), avoiding lumps, ensuring uniform calcination, and improving the efficiency and quality of high-temperature calcination.

[0042] The rotary kiln body also includes a secondary crushing mechanism disposed below the first filter plate 1001 and the second filter plate 1002; the secondary crushing mechanism includes a first friction plate 202 connected to the first filter plate 1001, a second friction plate 201 connected to the second filter plate 1002, and protrusions 203 connected to the opposite sidewalls of the first friction plate 202 and the second friction plate 201; a conical groove is formed between the second friction plate 201 and the first friction plate 202, allowing raw materials not crushed by the crushing roller 1005 to pass along the first filter plate. 1001 and the second filter plate 1002 slide between the second friction plate 201 and the first friction plate 202. When the second filter plate 1002 moves back and forth, it can drive the second friction plate 201 to move back and forth. At the same time, under the action of the protrusion 203, it can reciprocate to crush the agglomerated raw material. Furthermore, the gap between the second friction plate 201 and the first friction plate 202 is set in a conical shape, which can realize multi-stage crushing, making the crushing efficiency higher and the effect better, and the crushing effect better.

[0043] The driving mechanism includes a first movable plate 301 disposed within the kiln body 101, a first connecting plate 302 connected between the first movable plate 301 and the second filter plate 1002, and two first guide rods 303 connected to the first movable plate 301; the first guide rods 303 are disposed through the kiln tail 102; the driving mechanism also includes a U-shaped plate 305 connected to the first guide rods 303, a spring 304 connected between the U-shaped plate 305 and the kiln tail 102, and a pushing mechanism for moving the U-shaped plate 305; the spring 304 is sleeved on the side wall of the first guide rod 303, and through the action of the pushing mechanism and the spring 304, the U-shaped plate 305 and the first guide rod 303 can be pushed to reciprocate, thereby driving the first movable plate 301 to move, and then driving the second filter plate 1002 to move through the first connecting plate 302, making it easier and faster to move the second filter plate 1002.

[0044] The drive mechanism includes a driven bevel gear 403, a cam 405, and a rotating shaft 404 connecting the driven bevel gear 403 and the cam 405. The drive mechanism also includes a driving bevel gear 401 connected to the rotating rod 108 and a first connecting block 402 connecting the rotating shaft 404 and the cylinder 105. The rotating shaft 404 and the first connecting block 402 are rotatably connected. When the reduction motor 107 is started, the rotation of the reduction motor 107 drives the rotation of the rotating rod 108 and the spiral blade 109, thereby driving the original... The material is conveyed into the preheating box 501. At the same time, when the rotating rod 108 rotates, it can drive the driving bevel gear 401 to rotate, and at the same time, it can drive the driven bevel gear 403 to rotate. In turn, it drives the cam 405 to rotate through the rotating shaft 404. When the tip of the cam 405 abuts against the side wall of the U-shaped plate 305, it can push the U-shaped plate 305 and the first guide rod 303 to move. The rotation of the rotating rod 108 can be used as power, eliminating the need for an additional motor and reducing costs.

[0045] The rotary kiln body also includes a pre-crushing mechanism for pre-crushing the raw materials input into the cylinder 105; the pre-crushing mechanism includes a preheating box 501 connected to the cylinder 105, a filter screen 502 connected inside the preheating box 501, and a discharge port 504 located at the bottom of the preheating box 501; the pre-crushing mechanism also includes an extrusion plate 503 located inside the preheating box 501 and a lifting mechanism for driving the extrusion plate 503 to rise and fall; the extrusion plate 503 includes a baffle 505 extending through the top of the preheating box 501, allowing the raw materials inside the cylinder 105 to be conveyed into the preheating box 501 and positioned above the filter screen 502. At this time, the cylinder 105 and the preheating box 501... Located inside the kiln body 101, the raw materials can be preheated and dried. During this process, the raw materials may clump together. Unclumped raw materials can pass through the filter screen 502 and enter the discharge port 504. Clumped raw materials are located above the filter screen 502. When the first moving plate 301 moves back and forth, it can drive the extrusion plate 503 to move back and forth through the lifting mechanism. This allows the extrusion plate 503 to extrude the clumped raw materials above the filter screen 502 and pre-crush them under the action of the filter screen 502. This prevents the clumped raw materials from entering the kiln body 101 for calcination, making the raw materials more uniform in the kiln body 101 and improving the efficiency and quality of high-temperature calcination.

[0046] The lifting mechanism includes a connecting rod 702 rotatably connected to the baffle 505, a second connecting plate 601 connected to the first moving plate 301, and a support 701 connecting the connecting rod 702 and the second connecting plate 601. The lifting mechanism also includes a second connecting block 703 connected to the baffle 505 and a first spring telescopic rod 704 connecting the second connecting block 703 and the preheating box 501. The baffle 505 prevents the raw material from moving to the top of the extrusion plate 503. When the first moving plate 301 reciprocates, it can drive the second connecting plate 601 forward. The first moving plate 301 and the second connecting plate 601 move back and forth. When the second connecting plate 601 moves towards the preheating box 501, it can drive the baffle 505 and the extrusion plate 503 to move downward through the support 701 and the connecting rod 702. At the same time, the connecting rod 702 rotates. When the second connecting plate 601 moves away from the preheating box 501 to reset, it can drive the baffle 505 and the extrusion plate 503 to move upward to reset through the support 701 and the connecting rod 702. The extrusion plate 503 can be raised and lowered by the reciprocating movement of the first moving plate 301 and the second connecting plate 601, which is more convenient and faster.

[0047] The pre-crushing mechanism also includes a metering mechanism for metering the raw material discharged from the outlet 504 into the kiln body 101; the metering mechanism includes a sealing plate 605 connected to the preheating box 501, a second moving plate 602 connected to the second connecting plate 601, and a first metering groove 603 and a second metering groove 604 formed on the second moving plate 602; the first metering groove 603 and the second metering groove 604 are arranged through the second moving plate 602; the sealing plate 605 can control the first metering groove 603 and the second metering groove 604. The bottom of the 4-section is sealed, allowing the pre-crushed raw material to pass through the filter screen 502 and enter the discharge port 504. Simultaneously, when the second connecting plate 601 reciprocates, it drives the second moving plate 602 to reciprocate on the sealing plate 605. When the second metering trough 604 aligns with the discharge port 504, the raw material in the discharge port 504 can enter the second metering trough 604 for temporary storage. When the second connecting plate 601 moves away from the preheating box 501, it drives the second moving plate 602... Synchronous movement causes the second metering trough 604 to move away from above the sealing plate 605. At this time, the raw material temporarily stored in the second metering trough 604 can fall into the kiln body 101. Simultaneously, the first metering trough 603 is aligned with the discharge port 504, allowing the raw material in the discharge port 504 to enter and be temporarily stored in the first metering trough 603. Under the action of the sealing plate 605, the bottom of the first metering trough 603 is sealed. When the second connecting plate 601 moves towards the preheating box 501, it drives the second... The moving plate 602 moves synchronously, at which time the first metering trough 603 is moved away from below the discharge port 504, and the sealing plate 605 no longer seals the bottom of the first metering trough 603, so that the raw material temporarily stored in the first metering trough 603 can enter the kiln body 101. At the same time, the second metering trough 604 is aligned with the discharge port 504 again. By repeating this process, the raw material can be metered and fed into the kiln body 101, making the raw material entering the kiln body 101 more uniform and improving the efficiency and quality of high-temperature calcination.

[0048] The rotary kiln body also includes a pushing assembly disposed on the inner wall of the kiln body 101 for pushing the raw material to rotate with the kiln body 101; the pushing assembly includes multiple strip openings 901 opened on the inner lining 104, a pushing plate 902 sliding in the strip openings 901, and an inclined surface 903 disposed on the pushing plate 902; the pushing assembly also includes a second guide rod 904 connected to the pushing plate 902, a second fixing frame 905 connected to the outer wall of the kiln body 101, and a second spring telescopic rod 906 connected between the second guide rod 904 and the second fixing frame 905; the second guide rod 904 is disposed through the kiln body 101, and when the raw material is calcined in the kiln body 101, the kiln body 101 can drive the raw material to turn over. At the same time, under the action of the pushing plate 902, the raw material can be pushed to rotate with the kiln body 101 and fall onto the first filter plate 1001 under the action of gravity, which facilitates the falling of agglomerated raw material onto the first filter plate 1001.

[0049] The rotary kiln body also includes a cleaning mechanism installed inside the kiln body 101 for scraping and cleaning the rings on the lining 104. The cleaning mechanism includes multiple scrapers 802 and a support plate 801 connected between the scrapers 802 and the first moving plate 301. The scrapers 802 include stepped blocks 803 on both sides. During calcination, when the first moving plate 301 moves back and forth, it can drive the multiple scrapers 802 to move back and forth through the support plate 801. At this time, when there are rings on the surface of the lining 104, the scrapers 802 can scrape and clean the rings. At the same time, under the action of the stepped blocks 803, the rings can be scraped in sections to avoid forming large pieces after scraping, which facilitates subsequent crushing operations. It is also convenient to use the movement of the first moving plate 301 to scrape and clean the rings on the surface of the lining 104, thereby improving the efficiency of high-temperature calcination.

[0050] A process for producing polyaluminum chloride includes the following steps:

[0051] S1: Aluminum ash grading and pretreatment: Aluminum ash is screened in multiple stages by a professional mill. The high-purity aluminum ash separated is sent to an electric melting furnace to smelt aluminum blocks for sale. The remaining aluminum ash is precisely graded into low-aluminum ash (sealed for later use) and high-aluminum ash (used for subsequent calcination) according to the aluminum content. During the screening process, a bag filter dust collector is used to collect dust to reduce dust pollution.

[0052] S2: Raw material crushing and dust removal: Limestone and high-alumina limestone are crushed separately by jaw crushers, with the crushing particle size controlled at 20-50mm; a bag filter dust removal system is used throughout the crushing process to efficiently collect the generated dust, with a dust recovery rate of no less than 98%, to prevent dust leakage.

[0053] S3: Raw material homogenization treatment: The crushed limestone, high-alumina limestone and dust recovered from bag filter dust collection in each stage are sent together into the raw material homogenization silo. The raw material components are uniformly mixed by the air stirring device in the silo, and the homogenization coefficient is controlled within 1.5 to ensure the stability of the subsequent calcination reaction.

[0054] S4: Drying and Exhaust Gas Treatment: The homogenized raw material is fed into a rotary dryer for drying. The drying temperature is controlled at 120-150℃ to remove free moisture from the raw material to below 5%. Dust, SO2, and NO generated during the drying process are treated. x The exhaust gas is treated by a bag filter dust collector and an integrated desulfurization and denitrification device, and is discharged after meeting the standards. The exhaust gas treatment efficiency meets the GB16297-1996 standard.

[0055] S5: Fine grinding of raw materials: The dried raw materials are fed into a ball mill for fine grinding. After grinding, the fineness of the raw materials is controlled to have a sieve residue of ≤10% on an 80μm square hole sieve. The dust generated during the grinding process is collected in real time by a bag dust collection system. The collected dust is returned to the raw material homogenization stage for recycling, thus realizing resource recovery.

[0056] S6: Rotary Kiln Calcination Operation: The ground raw material is fed into the aluminum ash rotary kiln via a screw conveyor. At the same time, coal crushed to a particle size ≤10mm (treated by bag filter dust removal) is fed into the kiln body (101) through the burner at the kiln head 103 as fuel and burned in the kiln head 103 area to provide a high-temperature heat source for calcination. The calcination temperature is controlled at 1200-1400℃. The residence time of the raw material in the kiln body (101) is 30-45 minutes. During calcination, the rotation of the kiln body 101 can cause the raw material to tumble and fall onto the first filter plate 100 under the action of gravity. At the same time, the second filter plate 1002 can be driven to move back and forth through the drive mechanism, and multiple rolling rollers 1005 can be driven to roll back and forth through the first fixed frame 1003 and the rotating shaft 1004. At this time, the raw material on the first filter plate 1001 can be spread flat, and the agglomerated raw material can be crushed. The crushed and spread raw material can fall back into the kiln body 101 through the first filter plate 1001, ensuring that the raw material at the bottom of the kiln body (101) is evenly distributed, avoiding agglomeration, ensuring uniform calcination, and improving the efficiency and quality of high-temperature calcination.

[0057] S7: Clinker Processing and Dust Collection: The clinker calcined in the rotary kiln is temporarily stored in the clinker silo, and then further ground in a clinker grinding mill to a fineness ≥325 mesh to obtain calcium aluminate powder. Baghouse dust collectors are used to collect dust during the grinding process, with a dust recovery rate of 100%. The effective alumina content of the finished calcium aluminate powder is ≥50%.

[0058] S8: Low-alumina ash acidolysis reaction: Send the prepared low-alumina ash into a corrosion-resistant reaction tank, add industrial hydrochloric acid with a concentration of 20-25% at a liquid-to-solid ratio of 3:1, control the reaction temperature at 80-90℃, the stirring rate at 60r / min, and the reaction time at 2-3 hours to fully convert aluminum elements into aluminum chloride solution.

[0059] S9: Pressure Filtration Separation and Purification: After the acid hydrolysis reaction is completed, the slurry is sent to a plate and frame filter press for pressure filtration. The filtration pressure is controlled at 0.6-0.8 MPa to separate the filter residue (which is discharged after harmless treatment) and the clarified filtrate. The Al2O3 content of the filtrate is controlled at 8-10%.

[0060] S10: Compounding and performance adjustment: Pump the clarified filtrate into the compounding tank, add the finished calcium aluminate powder in proportion, adjust the pH of the slurry to 3.5-4.5, stir and compound at 50-60℃ for 1-1.5 hours to optimize the basicity (controlled at 40-90%) and flocculation performance of polyaluminum chloride.

[0061] S11: Finished product separation and refining: The compounded slurry is sent to a sedimentation tank for natural sedimentation (sedimentation time ≥ 8 hours) or is filtered again by a filter press to remove impurities and filter residue, and obtain liquid polyaluminum chloride product with a purity ≥ 98%. The filter residue can be recycled as building auxiliary material after drying.

[0062] S12: Finished Product Forming and Storage: Liquid polyaluminum chloride can be directly packaged for export; if solid products are required, the liquid polyaluminum chloride is sent to a spray drying tower and dried and formed under hot air conditions of 200-220℃ to obtain solid polyaluminum chloride particles (particle size 0.5-1.5mm). After the finished product passes inspection, it is sealed and packaged and stored in a dry and ventilated warehouse to avoid moisture absorption and deterioration.

[0063] Working principle: When the raw material needs to be calcined, the raw material to be calcined is put into the hopper 106 and then into the cylinder 105. At the same time, the reduction motor 107 is started. The rotation of the reduction motor 107 drives the rotation rod 108 and the spiral blade 109 to rotate, thereby driving the raw material in the cylinder 105 to be conveyed into the preheating box 501 and placed above the filter screen 502. The un-agglomerated raw material can pass through the filter screen 502 and enter the discharge port 504. At the same time, when the rotation rod 108 rotates, it can drive the driving bevel gear 401 to rotate, and at the same time, it can drive the driven bevel gear 403 to rotate, which in turn drives the cam 405 to rotate through the rotating shaft 404.

[0064] When the tip of the cam 405 abuts against the side wall of the U-shaped plate 305, it can push the U-shaped plate 305 and the first guide rod 303 to move, compressing the spring 304 and driving the first moving plate 301 and the second connecting plate 601 to move. When the tip of the cam 405 passes the side wall of the U-shaped plate 305, the U-shaped plate 305 and the first guide rod 303 can move back to their original position under the action of the spring 304, driving the first moving plate 301 and the second connecting plate 601 to move back to their original position. This reciprocating motion allows the first moving plate 301 and the second connecting plate 601 to move back and forth. When the second connecting plate 601 moves closer to the preheating box 501... When moving in a certain direction, the support 701 and connecting rod 702 can drive the baffle 505 and the extrusion plate 503 to move downward. At the same time, the connecting rod 702 rotates. When the second connecting plate 601 moves away from the preheating box 501 to reset, the support 701 and connecting rod 702 can drive the baffle 505 and the extrusion plate 503 to move upward to reset. By repeating this process, the extrusion plate 503 can extrude the raw material that has agglomerated above the filter screen 502 and pre-crush it under the action of the filter screen 502, thus preventing the agglomerated raw material from entering the kiln body 101 for calcination. This makes the raw material more uniform in the kiln body 101 and improves the efficiency and quality of high-temperature calcination.

[0065] Furthermore, the pre-crushed raw material can also enter the discharge port 504 through the filter screen 502. Simultaneously, when the second connecting plate 601 reciprocates, it drives the second moving plate 602 to reciprocate on the sealing plate 605. When the second metering trough 604 is aligned with the discharge port 504, the raw material in the discharge port 504 can enter the second metering trough 604 for temporary storage. When the second connecting plate 601 moves away from the preheating box 501, it drives the second moving plate 602 to move synchronously, causing the second metering trough 604 to move away from the sealing plate 605. At this time, the raw material temporarily stored in the second metering trough 604 can fall into the kiln body 101, and the first metering trough 603 is aligned with the discharge port 504. At this time, the discharge port 504... The raw material in 04 can enter the first metering trough 603 for temporary storage, and the bottom of the first metering trough 603 is sealed by the sealing plate 605. When the second connecting plate 601 moves towards the preheating box 501, it drives the second moving plate 602 to move synchronously. At this time, the first metering trough 603 is moved away from below the discharge port 504, and the sealing plate 605 no longer seals the bottom of the first metering trough 603, so that the raw material temporarily stored in the first metering trough 603 can enter the kiln body 101. In addition, the second metering trough 604 is aligned with the discharge port 504 again. By repeating this process, the raw material can be repeatedly metered into the kiln body 101, making the raw material entering the kiln body 101 more uniform and improving the efficiency and quality of high-temperature calcination.

[0066] When the raw materials are calcined inside the kiln body 101, the rotation of the kiln body 101 can cause the raw materials to tumble. At the same time, under the action of the push plate 902, the raw materials can be pushed to rotate with the kiln body 101 and fall onto the first filter plate 1001 under the action of gravity. Meanwhile, when the first moving plate 301 moves back and forth, it can drive the second filter plate 1002 to move back and forth through the first connecting plate 302, and drive multiple rolling rollers 1005 to roll back and forth through the first fixed frame 1003 and the rotating shaft 1004. At this time, the raw materials on the first filter plate 1001 can be spread flat, and the lumpy raw materials can be crushed. The crushed and spread raw materials can fall back into the kiln body 101 through the first filter plate 1001, thereby making the raw materials more uniform in the kiln body 101 and improving the efficiency and quality of high-temperature calcination.

[0067] Raw materials that are not crushed by the crushing roller 1005 can slide along the first filter plate 1001 and the second filter plate 1002 to the space between the second friction plate 201 and the first friction plate 202. When the second filter plate 1002 moves back and forth, it can drive the second friction plate 201 to move back and forth. At the same time, under the action of the convex strip 203, the agglomerated raw materials can be repeatedly rubbed and crushed. Furthermore, the gap between the second friction plate 201 and the first friction plate 202 is set in a conical shape, which can realize multi-stage crushing, making the crushing efficiency higher and the effect better.

[0068] Furthermore, during calcination, when the first moving plate 301 reciprocates, it can drive multiple scrapers 802 to reciprocate via the support plate 801. At this time, when there are rings on the surface of the lining 104, the scrapers 802 can scrape and clean the rings. At the same time, under the action of the step block 803, the rings can be scraped off in sections to avoid forming large pieces after scraping, which facilitates subsequent crushing operations.

[0069] The calcined raw materials are discharged through the discharge port at the bottom of the kiln head 103.

Claims

1. A rotary kiln for aluminum ash, comprising a rotary kiln body, the rotary kiln body including a kiln body (101), a kiln tail (102), a kiln head (103) and a screw conveyor for feeding material into the rotary kiln body, the kiln body (101) including an inner lining (104), the screw conveyor including a cylinder (105) communicating with the kiln body (101) and a rotating rod (108) disposed within the cylinder (105), characterized in that: The rotary kiln body also includes a crushing and spreading mechanism disposed inside the kiln body (101) for crushing and spreading the raw materials. The crushing and spreading mechanism includes a first filter plate (1001) connected to the kiln tail (102), a second filter plate (1002) moving within the kiln body (101), and a driving mechanism for driving the second filter plate (1002) to move; the first filter plate (1001) and the second filter plate (1002) are arranged at an incline downwards; the crushing and spreading mechanism also includes a plurality of crushing rollers (1005) above the first filter plate (1001), a plurality of first fixing frames (1003) connected to the second filter plate (1002), and a rotating shaft (1004) connecting the crushing rollers (1005) and the first fixing frames (1003). The rotary kiln body also includes a secondary crushing mechanism disposed below the first filter plate (1001) and the second filter plate (1002); the secondary crushing mechanism includes a first friction plate (202) connected to the first filter plate (1001), a second friction plate (201) connected to the second filter plate (1002), and a protrusion (203) connected to the opposite sidewalls of the first friction plate (202) and the second friction plate (201); a conical groove is formed between the second friction plate (201) and the first friction plate (202); The driving mechanism includes a first movable plate (301) disposed in the kiln body (101), a first connecting plate (302) connected between the first movable plate (301) and the second filter plate (1002), and two first guide rods (303) connected to the first movable plate (301).

2. The rotary kiln for aluminum ash according to claim 1, characterized in that: The first guide rod (303) is installed through the kiln tail (102); the driving mechanism also includes a U-shaped plate (305) connected to the first guide rod (303), a spring (304) connected between the U-shaped plate (305) and the kiln tail (102), and a pushing mechanism for moving the U-shaped plate (305); the spring (304) is sleeved on the side wall of the first guide rod (303).

3. The rotary kiln for aluminum ash according to claim 2, characterized in that: The drive mechanism includes a driven bevel gear (403), a cam (405), and a rotating shaft (404) connected between the driven bevel gear (403) and the cam (405); the drive mechanism also includes a driving bevel gear (401) connected to the rotating rod (108) and a first connecting block (402) connected between the rotating shaft (404) and the cylinder (105).

4. The rotary kiln for aluminum ash according to claim 1, characterized in that: The rotary kiln body also includes a pre-crushing mechanism for pre-crushing the raw materials input into the cylinder (105); the pre-crushing mechanism includes a preheating box (501) connected to the cylinder (105), a filter screen (502) connected to the preheating box (501), and a discharge port (504) set at the bottom of the preheating box (501); the pre-crushing mechanism also includes an extrusion plate (503) set in the preheating box (501) and a lifting mechanism for driving the extrusion plate (503) to rise and fall; the extrusion plate (503) includes a baffle (505) penetrating the top of the preheating box (501).

5. The rotary kiln for aluminum ash according to claim 4, characterized in that: The lifting mechanism includes a connecting rod (702) rotatably connected to the baffle (505), a second connecting plate (601) connected to the first moving plate (301), and a support (701) connected between the connecting rod (702) and the second connecting plate (601); the lifting mechanism also includes a second connecting block (703) connected to the baffle (505) and a first spring telescopic rod (704) connected between the second connecting block (703) and the preheating box (501).

6. The rotary kiln for aluminum ash according to claim 5, characterized in that: The pre-crushing mechanism also includes a metering mechanism for metering the raw material discharged from the discharge port (504) into the kiln body (101); the metering mechanism includes a sealing plate (605) connected to the preheating box (501), a second moving plate (602) connected to the second connecting plate (601), and a first metering groove (603) and a second metering groove (604) opened on the second moving plate (602); the first metering groove (603) and the second metering groove (604) are arranged through the second moving plate (602); the sealing plate (605) can dynamically seal the bottom of the first metering groove (603) and the second metering groove (604).

7. The rotary kiln for aluminum ash according to claim 1, characterized in that: The rotary kiln body also includes a pushing component disposed on the inner wall of the kiln body (101) for pushing the raw material to rotate with the kiln body (101); the pushing component includes multiple strip openings (901) opened on the inner lining (104), a pushing plate (902) sliding in the strip openings (901), and an inclined surface (903) disposed on the pushing plate (902); the pushing component also includes a second guide rod (904) connected to the pushing plate (902), a second fixing frame (905) connected to the outer wall of the kiln body (101), and a second spring telescopic rod (906) connected between the second guide rod (904) and the second fixing frame (905); the second guide rod (904) is disposed through the kiln body (101).

8. The rotary kiln for aluminum ash according to claim 2, characterized in that: The rotary kiln body also includes a cleaning mechanism disposed within the kiln body (101) for scraping and cleaning the rings on the lining (104); the cleaning mechanism includes multiple scrapers (802) and a support plate (801) connected between the scrapers (802) and the first moving plate (301); the scrapers (802) include stepped blocks (803) disposed on both sides.

9. A process for producing polyaluminum chloride, applied to a rotary kiln for producing aluminum ash as described in claim 1, characterized in that: Includes the following steps: S1: Aluminum ash grading and pretreatment: Aluminum ash is screened in multiple stages by a professional mill. The high-purity aluminum ash separated is sent to an electric melting furnace to smelt aluminum blocks for sale. The remaining aluminum ash is accurately graded into low-aluminum ash and high-aluminum ash according to the aluminum content. During the screening process, a bag filter dust collector is used to collect dust to reduce dust pollution. S2: Raw material crushing and dust removal: Limestone and high-alumina limestone are crushed separately by jaw crushers, with the crushing particle size controlled at 20-50mm; a bag filter dust removal system is used throughout the crushing process to efficiently collect the generated dust, with a dust recovery rate of no less than 98%, to prevent dust leakage. S3: Raw material homogenization treatment: The crushed limestone, high-alumina limestone and dust recovered from bag filter dust collection in each stage are sent together into the raw material homogenization silo. The raw material components are uniformly mixed by the air stirring device in the silo, and the homogenization coefficient is controlled within 1.5 to ensure the stability of the subsequent calcination reaction. S4: Drying and exhaust gas treatment: The homogenized raw material is sent to a rotary dryer for drying. The drying temperature is controlled at 120-150℃ to remove the free moisture of the raw material to below 5%. The drying process generates dust, SO2 and NO. x The exhaust gas is treated by a bag filter dust collector and an integrated desulfurization and denitrification device, and is discharged after meeting the standards. S5: Fine grinding of raw materials: The dried raw materials are fed into a ball mill for fine grinding. After grinding, the fineness of the raw materials is controlled to have a sieve residue of ≤10% on an 80μm square hole sieve. The dust generated during the grinding process is collected in real time by a bag dust collection system. The collected dust is returned to the raw material homogenization stage for recycling, thus realizing resource recovery. S6: Rotary Kiln Calcination Operation: The ground raw material is fed into the aluminum ash rotary kiln via a screw conveyor. At the same time, coal crushed to a particle size ≤10mm is fed into the kiln body (101) via the burner at the kiln head (103) as fuel and burned in the kiln head (103) area to provide a high-temperature heat source for calcination. The calcination temperature is controlled at 1200-1400℃. The raw material stays in the kiln body (101) for 30-45 minutes. During calcination, the rotation of the kiln body (101) can cause the raw material to tumble and fall onto the first filter plate (1001) under the action of gravity. The second filter plate (1002) can be driven to move back and forth through the drive mechanism, and multiple rolling rollers (1005) can be driven to roll back and forth through the first fixed frame (1003) and the rotating shaft (1004). At this time, the raw material on the first filter plate (1001) can be spread flat, and the agglomerated raw material can be crushed. The crushed and spread raw material can fall back into the kiln body (101) through the first filter plate (1001), ensuring that the raw material is evenly distributed at the bottom of the kiln body (101), avoiding agglomeration, ensuring uniform calcination, and improving the efficiency and quality of high-temperature calcination. S7: Clinker Processing and Dust Collection: The clinker calcined in the rotary kiln is temporarily stored in the clinker silo, and then ground to a fineness of ≥325 mesh by a clinker grinding mill to obtain calcium aluminate powder as the finished product. Baghouse dust collectors are used to collect dust during the grinding process, with a dust recovery rate of 100%. The effective alumina content of the finished calcium aluminate powder is ≥50%. S8: Low-alumina ash acidolysis reaction: Send the prepared low-alumina ash into a corrosion-resistant reaction tank, add industrial hydrochloric acid with a concentration of 20-25% at a liquid-to-solid ratio of 3:1, control the reaction temperature at 80-90℃, the stirring rate at 60r / min, and the reaction time at 2-3 hours to fully convert aluminum elements into aluminum chloride solution. S9: Pressure Filtration Separation and Purification: After the acid hydrolysis reaction is completed, the slurry is sent to a plate and frame filter press for pressure filtration. The filtration pressure is controlled at 0.6-0.8 MPa to separate the filter residue and the clarified filtrate. The Al2O3 content of the filtrate is controlled at 8-10%. S10: Compounding and performance adjustment: Pump the clarified filtrate into the compounding tank, add the finished calcium aluminate powder in proportion, adjust the pH of the slurry to 3.5-4.5, and stir and compound at 50-60℃ for 1-1.5 hours to optimize the basicity and flocculation performance of polyaluminum chloride. S11: Finished product separation and refining: The compounded slurry is sent to a sedimentation tank for natural sedimentation or is filtered again through a filter press to remove impurities and filter residue, and obtain liquid polyaluminum chloride product with a purity of ≥98%. The filter residue can be recycled as building auxiliary material after drying. S12: Finished Product Forming and Storage: Liquid polyaluminum chloride is directly packaged for export; if solid products are required, the liquid polyaluminum chloride is sent to a spray drying tower and dried and formed under hot air conditions of 200-220℃ to obtain solid polyaluminum chloride granules. After the finished product passes inspection, it is sealed and packaged and stored in a dry and ventilated warehouse to avoid moisture absorption and deterioration.

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