A battery grade iron oxide impurity removal apparatus and method

Abstract

The present application relates to the technical field of iron oxide filtering and impurity removing, and particularly relates to a battery-grade iron oxide impurity removing device and method. The iron oxide filter cake is crushed by a crushing roller, the crushed material slides along the two sides of the boss, is sprayed by a spraying pipe towards the two sides of the boss and the bottom end of the crushing roller, the turbid liquid after washing along the boss is introduced into a lower stirring cylinder, and large particle groups of material or large particle impurities which are not fully crushed and washed are intercepted by a filter screen, meanwhile, a reciprocating scraper is rotated to scrape the filter screen on the two sides of the boss and spread the scraped material onto the crushing roller, so as to reduce the material stacking on the filter screen and further improve the crushing and washing efficiency. The washing turbid liquid in the stirring cylinder is further stirred and sent to the next stage of filter pressing and washing operation to complete the impurity removing of the battery-grade iron oxide, reduce water pollution, solid waste pollution and heavy metal pollution caused by directly discharging solid waste iron mud, and the filter pressing mother liquor is further purified by high-efficiency activated carbon, ultrafiltration and reverse osmosis, which is beneficial to environmental protection.

Description

Technical Field

[0001] This invention relates to the field of iron oxide filtration and impurity removal technology, and in particular to a device and method for removing impurities from battery-grade iron oxide. Background Technology

[0002] The traditional reduction process for producing DSD acid generates a large amount of solid waste iron sludge. Direct discharge of this iron oxide sludge causes water pollution, solid waste pollution, and heavy metal pollution, posing challenges to enterprise development. Therefore, utilizing solid waste iron sludge to co-produce iron oxide products is urgently needed. Battery-grade iron oxide has no requirements regarding color; the main focus is on controlling impurity elements, particle size, and specific surface area. Impurities (such as Si, Al, Ca, Mg, Na, K, S, P, Cl, and heavy metals Cu, Zn, Cr, Ni, etc.) can severely affect the electrochemical performance of batteries. Therefore, impurity removal is a core and crucial process, typically achieved through a combination of methods. Wet chemical purification is a common existing treatment method, which includes targeted mixed acid washing / alkali washing / water washing, followed by solid-liquid separation (acid washing removes acid-soluble impurities from iron oxide, alkali washing removes alkali-soluble impurities from iron oxide, and water washing removes soluble salt impurities from iron oxide), followed by multiple washings with deionized water until neutral, and then drying and calcining to obtain high-purity battery-grade iron oxide products. Specific existing technologies, such as the wet purification and wastewater recycling method for iron oxide powder disclosed in Chinese patent document CN114655995B, often use a filter press for solid-liquid separation. The filter press mother liquor is discharged through the filter cloth, carrying away soluble impurities. The mother liquor from the filter press can be further purified by high-efficiency activated carbon, ultrafiltration, and reverse osmosis to reduce the impact of water pollution, solid waste pollution, and heavy metal pollution, which is beneficial to environmental protection. The iron oxide filter cake obtained from the filter press separation is then put into a washing tank and washed with acid / alkali / deionized water. The turbid liquid after washing is then passed into a filter press for further filtration. This cycle is repeated multiple times until the purity standard is met. Among these processes, how to efficiently and fully mix acid / alkali / deionized water to wash the iron oxide filter cake is obviously the key to removing impurities from iron oxide. This can improve the impurity removal efficiency and achieve the requirement of less impurity residue after a limited number of washing separations. Therefore, further research and optimization are still needed. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a battery-grade iron oxide impurity removal device and method to solve the problem of how to more efficiently and fully mix acid / alkali / deionized water to wash the iron oxide filter cake in existing iron oxide impurity removal processes.

[0004] To achieve the above objectives, the present invention provides a device for removing impurities from battery-grade iron oxide, comprising a horizontally positioned impurity removal cylinder: The impurity removal cylinder includes an upper crushing cylinder and a lower stirring cylinder. The inner cavity of the crushing cylinder is a horizontally placed cylindrical shape. The top of the crushing cylinder has a feed inlet. Crushing rollers are rotatably connected to the upper two sides of the crushing cylinder. A boss is provided on the bottom wall of the crushing cylinder. The feed material after being crushed by the crushing rollers slides down along the two sides of the boss. A spray pipe is provided inside the crushing cylinder for spraying towards the two sides of the boss. The inner bottom wall of the crushing cylinder has discharge ports on both sides of the boss, and filter screens are installed on the discharge ports; The crushing drum is equipped with a scraper frame, one end of which is connected to a scraper assembly. The scraper assembly includes two scraper blades connected in a V-shape. The meeting end of the two scraper blades is rotatably connected to the scraper frame. Each of the two scraper blades has an opening near its meeting end. One end of the scraper frame is connected to an extension plate in parallel. One of the scraper blades is in a state parallel to the scraper frame and closes the corresponding opening through the extension plate. The other end of the scraper frame reciprocates around the axial direction inside the crushing drum, driving one of the scraper blades to scrape the filter screen and sprinkle the scraped material down onto the crushing roller along the open opening. When the scraper frame rotates to the other side of the boss, the side end of the boss pushes against the scraper assembly, so that the other scraper blade rotates to be parallel to the scraper frame.

[0005] Preferably, the crushing roller is arranged parallel to the crushing cylinder, and the spray pipe is arranged parallel to the adjacent lower part of the crushing roller.

[0006] Preferably, a plurality of spray heads are arranged at intervals along the outer periphery of the spray pipe for spraying toward the side end of the boss and the bottom end of the crushing roller.

[0007] Preferably, the length direction of the boss is parallel to the axial direction of the crushing cylinder, and the cross-section of the boss is fan-shaped.

[0008] Preferably, the impurity removal device is located at the bottom of the filter press, and a stirring shaft is provided inside the stirring drum. A liquid outlet pipe is connected to one side of the stirring drum, and one end of the liquid outlet pipe leads to an adjacent filter press.

[0009] Preferably, a transition part is rotatably connected at the center of one side wall of the crushing cylinder. The scraper includes a connecting rod inside the crushing cylinder near the transition part. The length direction of the connecting rod is parallel to the radial direction inside the crushing cylinder. One end of the connecting rod is connected to a U-shaped connecting frame, and the other end is connected to the transition part. A rotating shaft is fixedly connected to the intersection of the two scraper plates. Shaft holes that are rotatably connected to the rotating shaft are opened on both sides of the connecting frame. One end of the extension plate is fixedly connected to the inner side of the connecting frame.

[0010] Preferably, the scraper has strip-shaped grooves on both sides of its opening, and the side end of the extension plate is elastically connected to a limiting strip. The limiting strip is designed with an inclined end face along its length. When one scraper is parallel to the scraper frame, the limiting strip pops outward along the corresponding strip-shaped groove until the scraper frame rotates to the side end of the boss. The scraper assembly is pushed by the side end of the boss, and the limiting strip is pushed inward by the inner end of the strip-shaped groove, so that the scraper assembly rotates until the scraper frame abuts against the side end of the boss, and the other scraper rotates to be parallel to the scraper frame.

[0011] Preferably, when the scraper plate rotates to abut against the side of the boss, the outer end of the scraper plate is designed with an inclined end face away from the boss. As the scraper plate scrapes the filter screen, the scraped material gradually decreases and accumulates between the inclined end face of the scraper plate and the inner wall of the crushing cylinder until the scraper frame starts to rotate downwards, and the scraped material slides down along the inclined end face of the scraper plate.

[0012] The present invention also provides a method for removing impurities from battery-grade iron oxide, comprising the following steps: Iron oxide filter cake falls into the crushing cylinder through the feed inlet, where it is crushed by the rotating crushing rollers. The crushed material slides down along the sides of the boss and is sprayed through the spray pipes towards the sides of the boss and the bottom of the crushing rollers. The turbid liquid after washing along the boss flows into the lower mixing drum through the discharge port, where it passes through the filter screen to trap large clumps or impurities that have not been fully crushed and washed. At the same time, a scraper reciprocates axially around the inside of the crushing cylinder, driving one of the scraper plates to scrape the filter screen and scatter the scraped material down onto the crushing rollers through the open outlet. When the scraper moves to the other side of the boss, it pushes against the scraper assembly by the side end of the boss, so that another scraper plate moves to be parallel to the scraper. The scraper plate parallel to the scraper scrapes the filter screen on the other side of the boss and sprinkles the scraped material down onto the crushing roller through the open passage, thereby reducing the accumulation of material on the filter screen and further improving the crushing and washing efficiency. The washing liquid in the mixing drum is stirred by the stirring shaft, further crushed and washed, and then sent to the next stage of pressure filtration and washing operation. The iron oxide filter cake obtained by multi-stage pressure filtration separation realizes the removal of impurities from battery-grade iron oxide.

[0013] The beneficial effects of this invention are as follows: Iron oxide filter cake falls into the crushing cylinder through the feed inlet, is crushed by the rotating crushing rollers, and the crushed material slides down along both sides of the boss. Simultaneously, it is sprayed through spray pipes towards both sides of the boss and the bottom of the crushing rollers. The turbid liquid washed along the boss flows through the discharge outlet into the lower stirring cylinder. Large particles or impurities that are not fully crushed and washed are trapped by the filter screen. Meanwhile, a scraper reciprocates axially around the inside of the crushing cylinder to scrape the filter screen on both sides of the boss and to move the scraped material along the open... The material is poured downwards onto the crushing rollers, reducing material buildup on the filter screen and further improving crushing and washing efficiency. The washing liquid in the mixing drum is stirred by the stirring shaft for further crushing and washing before being sent to the next stage of pressure filtration and washing. The iron oxide filter cake obtained from multi-stage pressure filtration removes impurities from battery-grade iron oxide, thereby achieving co-production of solid waste iron sludge and reducing water pollution, solid waste pollution, and heavy metal pollution caused by direct discharge. Furthermore, the mother liquor from the pressure filtration can be further purified by high-efficiency activated carbon, ultrafiltration, and reverse osmosis, which is beneficial to environmental protection. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in this invention 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 for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the structure of the scraper frame of the present invention when it is attached to one side of the boss; Figure 3 This is a schematic diagram of the structure of the adapter of the present invention; Figure 4 This is a side view of the scraper assembly of the present invention. Figure 5 This is a front view of a single scraper blade of the present invention; Figure 6 This is a side view of the scraper frame of the present invention, with an extension plate connected to one end. Figure 7 This is a front view of the scraper frame of the present invention, with an extension plate connected to one end. Figure 8 This is a front view schematic diagram of the extension plate and limiting strip of the present invention; Figure 9 This is a side view of the scraper frame of the present invention, with a scraper assembly connected to one end. Figure 10 This is a schematic diagram of the scraper frame of the present invention rotating clockwise around the inside of the crushing cylinder; Figure 11 This is a schematic diagram of the structure of the scraper plate of the present invention when it rotates clockwise to the upper part of the crushing roller; Figure 12 For the present invention Figure 11 Enlarged view of point A in the middle; Figure 13 This is a schematic diagram of the structure of the scraper of the present invention when it is rotated to the other side of the boss; Figure 14 This is a schematic diagram of the structure when the other side end of the boss of the present invention pushes against the scraper assembly; Figure 15 For the present invention Figure 14 Enlarged view of point B in the middle; Figure 16 This is a schematic diagram of the structure of the scraper of the present invention when it is attached to the other side of the boss; Figure 17 For the present invention Figure 16 Enlarged view of point C in the middle; Figure 18 This is a schematic diagram of the structure of the scraper plate of the present invention when it rotates counterclockwise to the upper part of the crushing roller; Figure 19 This is a schematic diagram of the structure of the present invention when the scraper material accumulates between the inclined end face of the scraper plate and the inner wall of the crushing cylinder; Figure 20 For the present invention Figure 19 Enlarged view of point D in the middle; Figure 21 This is a top view of the extension plate and the limiting strip of the present invention.

[0016] The diagram is marked as follows: 100. Impurity removal cylinder; 101. Crushing cylinder; 102. Stirring cylinder; 103. Stirring shaft; 104. Liquid outlet pipe; 105. Liquid inlet pipe; 200. Filter press; 2. Feed inlet; 3. Crushing roller; 31. Crushing teeth; 4. Boss; 5. Spray pipe; 51. Spray head; 6. Discharge port; 7. Scraper frame; 71. Connecting rod; 72. Connecting frame; 73. Shaft hole; 8. Scraper plate; 80. Through port; 81. Rotating shaft; 82. Strip groove; 9. Extension plate; 91. Limiting strip; 10. Transfer part. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0018] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0019] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 As shown, a purification device for battery-grade iron oxide includes a horizontally placed purification cylinder 100. The purification cylinder 100 includes an upper pulverizing cylinder 101 and a lower stirring cylinder 102. The inner cavity of the pulverizing cylinder 101 is a horizontally placed cylindrical shape. A feed inlet 2 is opened at the top of the pulverizing cylinder 101. Pulverizing rollers 3 are rotatably connected to the upper two sides of the pulverizing cylinder 101. A boss 4 is provided on the inner bottom wall of the pulverizing cylinder 101. The feed material after being pulverized by the pulverizing rollers 3 slides down along the two sides of the boss 4. A spray pipe 5 is provided inside the pulverizing cylinder 101 for spraying towards the two sides of the boss 4. A discharge port 6 is opened on the inner bottom wall of the pulverizing cylinder 101 at the two sides of the boss 4. A filter screen is provided on the discharge port 6. A scraper 7 is provided inside the pulverizing cylinder 101. One end of the scraper 7 is connected to A scraper assembly is provided, which includes two scraper plates 8 connected in a V-shape. The confluence of the two scraper plates 8 is rotatably connected to the scraper frame 7. The two scraper plates 8 have openings 80 near their confluence. One end of the scraper frame 7 is connected to an extension plate 9 in parallel. One scraper plate 8 is in a state parallel to the scraper frame 7 and closes the corresponding opening 80 through the extension plate 9. The other end of the scraper frame 7 reciprocates in the axial direction inside the crushing cylinder 101, driving one of the scraper plates 8 to scrape the filter screen and sprinkle the scraped material down onto the crushing roller 3 along the open opening 80. When the scraper frame 7 rotates to the other side of the boss 4, the side end of the boss 4 pushes against the scraper assembly, so that the other scraper plate 8 rotates to be parallel to the scraper frame 7.

[0020] This invention is based on existing wet impurity removal processes and equipment for iron oxide. It includes a horizontally positioned impurity removal cylinder 100 for wet washing. The impurity removal cylinder 100 comprises an upper crushing cylinder 101 and a lower stirring cylinder 102. The washed turbid liquid is passed into conventional high-efficiency filtration equipment such as a filter press 200 for solid-liquid separation. Therefore, the impurity removal equipment of this invention can be installed independently or at the bottom of equipment such as a filter press 200. The iron oxide filter cake obtained from the filter press separation falls into the impurity removal cylinder 100. A suitable acid / alkali / deionized water is passed into the impurity removal cylinder 100 as the washing liquid. The iron oxide is first crushed by the upper crushing cylinder 101 and then mixed and stirred by the lower stirring cylinder 102. A stirring shaft 103 may be arranged parallel to the cylinder 102. A liquid outlet pipe 104 is connected to one side of the stirring cylinder 102. Stirring blades are provided on the outer periphery of the stirring shaft 103. One end of the liquid outlet pipe 104 can connect to an adjacent filter press 200. For example, three filter presses 200 can be arranged in parallel to form a filter press unit. The bottom of the first two filter presses 200 is equipped with a cleaning cylinder 100. The cylinder is rotated by the stirring shaft 103 to fully mix and wash the crushed iron oxide filter cake with the washing liquid. The turbid liquid after washing is pushed to the outlet pipe 104 and then to the next adjacent filter press 200 for secondary filtration and washing. The turbid liquid after secondary filtration and washing is then to the next adjacent filter press 200 for tertiary filtration. The mother liquor from filtration is discharged through the filter cloth and recycled or discharged. The iron oxide filter cake obtained from each filtration is equivalent to undergoing one solid-liquid separation (acid washing to remove acid-soluble impurities from iron oxide, alkali washing to remove alkali-soluble impurities from iron oxide, and water washing to remove soluble salt impurities from iron oxide). The iron oxide filter cake obtained from the three filtrations is then dried and calcined to finally obtain a high-purity battery-grade iron oxide product. The grinding cylinder 101 has a horizontally placed cylindrical inner cavity. A feed inlet 2 is located at the top of the grinding cylinder 101. Grinding rollers 3 are rotatably connected to the upper two sides of the grinding cylinder 101. A boss 4 is located on the bottom wall of the grinding cylinder 101. A spray pipe 5 is located inside the grinding cylinder 101. A discharge outlet 6 is located on both sides of the boss 4 on the bottom wall of the grinding cylinder 101, and communicates with the lower stirring cylinder 102 through the discharge outlet 6. A filter screen is installed on the discharge outlet 6. A scraper 7 is located inside the grinding cylinder 101, with a scraper assembly connected to one end of the scraper 7. Specifically, the grinding rollers 3 are arranged parallel to the grinding cylinder 101. A conventional power device, such as a drive motor, is connected to the side of the grinding cylinder 101 away from the liquid outlet pipe 104 to drive the grinding rollers 3 on both sides to rotate relative to each other. Figure 1 , Figure 2As shown, the outer circumference of the crushing roller 3 is provided with crushing teeth 31. The crushing teeth 31 on both sides of the crushing roller 3 are staggered. The left crushing roller 3 rotates clockwise and the right crushing roller 3 rotates counterclockwise. The length direction of the boss 4 is parallel to the axial direction of the crushing cylinder 101. The cross-section of the boss 4 is fan-shaped. The tip of the boss 4 is located below the middle of the two crushing rollers 3. The spray pipe 5 is arranged parallel to the adjacent lower part of the crushing roller 3. The side of the crushing cylinder 101 away from the liquid outlet pipe 104 is connected to the liquid inlet pipe 105. The liquid inlet pipe 105 penetrates into the crushing cylinder 101 and is connected to the spray pipe 5 for introducing washing liquid. Multiple spray heads 51 are arranged at intervals along the outer circumference of the spray pipe 5. Multiple rows of spray heads 51 are arranged at intervals along the length direction of the spray pipe 5 and multiple rows are arranged at intervals along the circumferential direction of the spray pipe 5. Thus, the iron oxide filter cake falls into the crushing cylinder 101 from the feed port 2 and is crushed by the powder... The crushing roller 3 rotates and crushes the material, which then slides down along the two sides of the boss 4. At the same time, multiple spray nozzles 51 spray the material in a directional manner towards the two sides of the boss 4 and the bottom of the crushing roller 3. On the one hand, the crushed material is efficiently dispersed as it slides down along the sides of the boss 4, making it less prone to accumulating. It also receives the spray and mixes with the washing liquid, achieving a thorough and efficient washing effect. On the other hand, the spray washes away the crushed material adhering to the bottom of the crushing roller 3. The adhering crushed material is blown towards the tip of the boss 4 and slides down, achieving a thorough and efficient washing effect. The turbid liquid washed along the boss 4 is fed into the lower stirring drum 102 through the discharge port 6. Large particles or impurities that have not been fully crushed and washed are intercepted by the filter screen. The washing turbid liquid in the stirring drum 102 is stirred by the stirring shaft 103, which further crushes and washes the small particles that have not been fully crushed and washed. The turbid liquid is then sent to the next stage of pressure filtration and washing operation through the liquid outlet pipe 104. The scraper assembly includes two scraper blades 8 connected in a V-shape. The confluence of the two scraper blades 8 is rotatably connected to a scraper frame 7. Each scraper blade 8 has an opening 80 near its confluence. One end of the scraper frame 7 is connected parallel to an extension plate 9. One scraper blade 8 is parallel to the scraper frame 7 and closes the corresponding opening 80 via the extension plate 9. The other end of the scraper frame 7 reciprocates axially within the crushing cylinder 101. The scraper frame 7 can be activated when the iron oxide filter cake begins to fall, or it can be activated during the middle to later stages of the iron oxide filter cake falling (when material tends to accumulate at the filter screen). Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9As shown, the scraper frame 7 abuts against one side of the boss 4. One scraper plate 8 is parallel to the scraper frame 7, and its opening 80 is closed by the extension plate 9. The other scraper plate 8 is V-shaped and tilted outwards, with its opening 80 naturally open. As the scraper frame 7 rotates clockwise around the crushing cylinder 101, it drives one of the scraper plates 8 to scrape the filter screen. Figure 10 As shown, large clumps or impurities that are not fully crushed and washed are scraped off by the scraper plate 8. The scraper plate 8 rotates upwards until it reaches the upper part of the crushing roller 3. Figure 11 , Figure 12 As shown, the scraper feeds material downwards along the open opening 80 onto the crushing roller 3. Even if some scraped material falls onto the upper part of the crushing roller 3, it can be carried by the rotation of the crushing roller 3 to the middle of the two crushing rollers 3 for further crushing and washing, avoiding material accumulation on the filter screen that affects the washing and feeding process, until the scraper frame 7 rotates to the other side of the boss 4, as... Figure 13 , Figure 14 , Figure 15 As shown, the scraper assembly is pushed against the side of the boss 4 until the scraper frame 7 is against the other side of the boss 4, as... Figure 16 , Figure 17 As shown, another scraper 8 is rotated to be parallel to the scraper frame 7. At this time, the scraper 8 rotates counterclockwise again, relying on the scraper 8 parallel to the scraper frame 7 to scrape the filter screen on the other side of the boss 4 until the scraper frame 7 rotates to the top of the crushing roller 3, as shown. Figure 18 As shown, the scraper also sprinkles the material downwards onto the crushing roller 3 through the open opening 80. As the scraper 7 reciprocates, after the iron oxide filter cake falls off, the scraper 7 continues to reciprocate for a period of time until the material piled on the filter screen is completely consumed, thereby further improving the crushing and washing efficiency.

[0021] In particular, for multi-stage pressure filtration washing, considering that the soluble impurities in the iron oxide filter cake decrease step by step, the washing flow rate of the spray pipe 5 can be adaptively reduced step by step. More preferably, in the same stage of pressure filtration washing, in the later stage of iron oxide filter cake falling and after falling, as the material on the filter screen is gradually consumed, the washing flow rate of the spray pipe 5 can also be adaptively reduced step by step.

[0022] In embodiments of the present invention, optionally, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9As shown, a transition part 10 is rotatably connected to the center of one side wall of the pulverizing cylinder 101. The transition part 10 is located on the same side as the liquid outlet pipe 104. Specifically, it can be a component such as a turntable. The scraper 7 includes a connecting rod 71 inside the pulverizing cylinder 101 near the transition part 10. The length direction of the connecting rod 71 is parallel to the radial direction inside the pulverizing cylinder 101. One end of the connecting rod 71 is connected to a U-shaped connecting frame 72, and the other end is connected to the inner side of the transition part 10. Specifically, the connecting rod 71 is connected to one side of the U-shaped connecting frame 72, that is, the side near the transition part 10. Since the pulverizing roller 3 and the spray pipe 5 are both connected to the side of the pulverizing cylinder 101 away from the transition part 10, that is, there is a gap between them and the side of the pulverizing cylinder 101 near the transition part 10, thus connecting... The rod 71 rotates in the gap near the transfer part 10 inside the crushing cylinder 101, without interfering with the crushing roller 3 or the spray pipe 5. Specifically, the outside of the crushing cylinder 101 can be equipped with one of the existing conventional power equipment designs, such as a servo motor with a motion controller, a stepper motor with a stepper driver, or a swing cylinder with a solenoid valve, to drive the transfer part 10 to rotate axially. The two scraper plates 8 are fixedly connected to the intersection of the two scraper plates 8 with a rotating shaft 81. The length direction of the scraper plate 8 is parallel to the length direction inside the crushing cylinder 101. The two sides of the U-shaped connecting frame 72 are respectively connected to the two sides of the length direction of the scraper plate 8. Specifically, the two sides of the connecting frame 72 are provided with shaft holes 73 that are rotatably connected to the rotating shaft 81. One end of the extension plate 9 is fixedly connected to the inside of the connecting frame 72.

[0023] The two sides of the U-shaped connecting frame 72 can be designed to be as short as possible to prevent scraping material from falling along the U-shaped space of the connecting frame 72.

[0024] Optionally, a support wheel may be provided at the top middle section of the boss 4 or the top middle section of the spray pipe 5. The support wheel abuts against the bottom end of the crushing roller 3 and rotates synchronously with the crushing roller 3. This is used to stably support the rotation of the crushing roller 3 without affecting the scraping movement of the scraper frame 7 and the scraper assembly.

[0025] In embodiments of the present invention, optionally, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 21 As shown, the scraper plate 8 has strip-shaped grooves 82 on both sides of its opening 80, and the strip-shaped grooves 82 communicate with their corresponding openings 80. A limit strip 91 is elastically connected to the side end of the extension plate 9, as shown. Figure 8 , Figure 21As shown, the limiting strip 91 has an inclined end face design along its length. When one of the scraper plates 8 is parallel to the scraper frame 7, the limiting strip 91 pops outward along the corresponding strip groove 82. Because the scraper is relatively light, the scraper weight and the friction between the outer end of the scraper plate 8 and the inner wall of the crushing cylinder 101 are insufficient to overcome the elastic force of the limiting strip 91 popping out. Thus, the limiting strip 91 is used to keep one of the scraper plates 8 parallel to the scraper frame 7 until the scraper frame 7 rotates to the side end of the boss 4, as shown. Figure 13 , Figure 14 , Figure 15 As shown, the scraper assembly is pushed against the side end of the boss 4. At this time, the limiting strip 91 is pushed inward by the inner end of the strip groove 82 and elastically contracts inward. The limiting strip 91 moves away from the strip groove 82, and the scraper assembly begins to rotate until the scraper frame 7 abuts against the side end of the boss 4, as shown. Figure 16 , Figure 17 As shown, the other scraper 8 rotates to be parallel to the scraper frame 7, that is, the limiting strip 91 pops out and extends into the strip groove 82 of the other scraper 8, which serves as a limiting function.

[0026] In embodiments of the present invention, optionally, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 12 , Figure 13 , Figure 14 , Figure 15 , Figure 16 , Figure 17 , Figure 18 As shown, when the scraper plate 8 rotates to abut against the side of the boss 4, the outer end of the scraper plate 8 is designed with an inclined end face away from the boss 4. On the one hand, the sharper outer end design of the scraper plate 8 facilitates more efficient scraping of the filter screen and reduces the friction between it and the inner wall of the crushing cylinder 101. On the other hand, in the initial stage of scraping by the scraper plate 8, due to the large amount of scraped material, some scraped material may fall downwards along the open opening 80 before the scraper plate 8 rotates to the upper part of the crushing roller 3, thus not being carried by the crushing roller 3 to be crushed and washed again. That is, only a portion of the scraped material will be carried into the crushing and washing process. As the scraped material obtained by the scraper plate 8 from scraping the filter screen gradually decreases, the scraped material can accumulate between the inclined end face of the scraper plate 8 and the inner wall of the crushing cylinder 101, such as... Figure 19 , Figure 20As shown, the scraper material only slides down the inclined end face of the scraper plate 8 when the scraper frame 7 starts to rotate downwards, and falls into the middle of the crushing rollers 3 on both sides, so as to crush and wash again, thereby further improving the crushing and washing efficiency.

[0027] Optionally, the outer end of the scraper 8, i.e. the end facing the inner wall of the crushing cylinder 101, can be designed as an elastic telescopic structure, similar to existing conventional elastic telescopic rods, elastic telescopic cylinders, etc. The outer end of the scraper 8 can also be made of elastic wear-resistant materials such as conventional rubber, so that even if the outer end of the scraper 8 wears down after long-term use, the outer end of the scraper 8 will still elastically abut against the inner wall of the crushing cylinder 101.

[0028] Optionally, the pulverizing cylinder 101 may also be equipped with an observation window to facilitate observation of the pulverizing and washing process inside the pulverizing cylinder 101 and to facilitate maintenance of the pulverizing and washing components inside the pulverizing cylinder 101. The stirring cylinder 102 may also be equipped with an online conductivity meter / pH meter to monitor the conductivity / pH of the washing liquid online, for monitoring the washing process and to assist in adaptively adjusting the spray flow rate and scraping frequency.

[0029] The present invention also provides a method for removing impurities from battery-grade iron oxide, comprising the following steps: Iron oxide filter cake falls into the crushing cylinder 101 through the feed inlet 2 and is crushed by the rotating crushing roller 3. The crushed material slides down along the two sides of the boss 4, and is simultaneously sprayed directionally by multiple spray nozzles 51 towards the two sides of the boss 4 and the bottom of the crushing roller 3. The turbid liquid washed along the boss 4 is discharged into the lower stirring cylinder 102 through the discharge port 6. Large particles or impurities that are not fully crushed and washed are intercepted by the filter screen. At the same time, the scraper 7 reciprocates axially around the crushing cylinder 101, driving one of the scraper plates 8 to scrape the filter screen and scatter the scraped material down onto the crushing roller 3 through the open outlet 80. When the scraper 7 rotates to the other side of the boss 4, it pushes against the scraper assembly through the side end of the boss 4, so that another scraper 8 rotates to be parallel to the scraper 7. The scraper 8, which is parallel to the scraper 7, scrapes the filter screen on the other side of the boss 4 and sprinkles the scraped material down onto the crushing roller 3 through the open opening 80, thereby reducing the accumulation of material on the filter screen and further improving the crushing and washing efficiency. The washing liquid in the mixing drum 102 is stirred by the stirring shaft 103 and further crushed and washed. Then it is sent to the next stage of pressure filtration and washing operation through the liquid outlet pipe 104. The iron oxide filter cake obtained by multi-stage pressure filtration and separation realizes the removal of impurities from battery-grade iron oxide.

[0030] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A device for removing impurities from battery-grade iron oxide, comprising a horizontally placed impurity removal cylinder (100), characterized in that: The impurity removal cylinder (100) includes an upper crushing cylinder (101) and a lower stirring cylinder (102). The inner cavity of the crushing cylinder (101) is a horizontally placed cylindrical shape. The top of the crushing cylinder (101) is provided with a feed inlet (2). Crushing rollers (3) are rotatably connected to the upper two sides of the crushing cylinder (101). A boss (4) is provided on the bottom wall of the crushing cylinder (101). The feed material after being crushed by the crushing rollers (3) slides down along the two sides of the boss (4). A spray pipe (5) is provided inside the crushing cylinder (101) for spraying towards the two sides of the boss (4). The inner bottom wall of the crushing cylinder (101) is provided with discharge ports (6) on both sides of the boss (4), and a filter screen is provided on the discharge port (6); The crushing cylinder (101) is equipped with a scraper (7). One end of the scraper (7) is connected to a scraper assembly. The scraper assembly includes two scraper blades (8) connected in a V-shape. The confluence of the two scraper blades (8) is rotatably connected to the scraper (7). The two scraper blades (8) are respectively provided with openings (80) near their confluence. One end of the scraper (7) is connected to an extension plate (9) in parallel. One of the scraper blades (8) is in a state parallel to the scraper (7). The corresponding opening (80) is closed by the extension plate (9). The other end of the scraper (7) rotates back and forth in the axial direction inside the crushing cylinder (101), driving one of the scraper plates (8) to scrape the filter screen and sprinkle the scraped material down onto the crushing roller (3) along the open opening (80) until the scraper (7) rotates to the other side of the boss (4). The scraper assembly is pushed by the side end of the boss (4) so ​​that the other scraper plate (8) rotates to be parallel to the scraper (7).

2. The impurity removal equipment for battery-grade iron oxide according to claim 1, characterized in that, The crushing roller (3) is arranged parallel to the crushing cylinder (101), and the spray pipe (5) is arranged parallel to the adjacent lower part of the crushing roller (3).

3. The impurity removal equipment for battery-grade iron oxide according to claim 1, characterized in that, The spray pipe (5) is provided with multiple spray heads (51) spaced apart along its outer periphery for spraying toward the side end of the boss (4) and the bottom end of the crushing roller (3).

4. The impurity removal equipment for battery-grade iron oxide according to claim 1, characterized in that, The length direction of the boss (4) is parallel to the axial direction of the crushing cylinder (101), and the cross-section of the boss (4) is fan-shaped.

5. The impurity removal equipment for battery-grade iron oxide according to claim 1, characterized in that, The impurity removal device is located at the bottom of the filter press (200). The stirring drum (102) is equipped with a stirring shaft (103). A liquid outlet pipe (104) is connected to one side of the stirring drum (102). One end of the liquid outlet pipe (104) is connected to the adjacent filter press (200).

6. The impurity removal equipment for battery-grade iron oxide according to claim 1, characterized in that, A transition part (10) is rotatably connected to the center of one side wall of the crushing cylinder (101). The scraper (7) includes a connecting rod (71) inside the crushing cylinder (101) near the transition part (10). The length direction of the connecting rod (71) is parallel to the radial direction inside the crushing cylinder (101). One end of the connecting rod (71) is connected to a U-shaped connecting frame (72), and the other end is connected to the transition part (10). A rotating shaft (81) is fixedly connected to the confluence of the two scraper plates (8). Shaft holes (73) that are rotatably connected to the rotating shaft (81) are opened on both sides of the connecting frame (72). One end of the extension plate (9) is fixedly connected to the inner side of the connecting frame (72).

7. The impurity removal equipment for battery-grade iron oxide according to claim 1, characterized in that, The scraper (8) has strip-shaped grooves (82) on both sides of its opening (80). The side end of the extension plate (9) is elastically connected to a limiting strip (91). The limiting strip (91) is designed with an inclined end face along its length direction. When one of the scraper (8) is parallel to the scraper frame (7), the limiting strip (91) pops outward along the corresponding strip-shaped groove (82) until the scraper frame (7) rotates to the side end of the boss (4). The scraper assembly is pushed by the side end of the boss (4). The limiting strip (91) is pushed inward by the inner end of the strip-shaped groove (82) so that the scraper assembly rotates until the scraper frame (7) abuts against the side end of the boss (4). The other scraper (8) rotates to be parallel to the scraper frame (7).

8. The impurity removal equipment for battery-grade iron oxide according to claim 6, characterized in that, When the scraper (8) rotates to abut against the side of the boss (4), the outer end of the scraper (8) is designed with an inclined end face away from the boss (4). As the scraper (8) scrapes the filter screen, the scraped material gradually decreases. The scraped material accumulates between the inclined end face of the scraper (8) and the inner wall of the crushing cylinder (101) until the scraper frame (7) starts to rotate downwards, and the scraped material slides down along the inclined end face of the scraper (8).

9. A method for removing impurities from battery-grade iron oxide, wherein the method employs the impurity removal equipment for battery-grade iron oxide as described in any one of claims 1-8, characterized in that, Includes the following steps: Iron oxide filter cake falls into the crushing cylinder (101) through the feed inlet (2) and is crushed by the rotating crushing roller (3). The crushed material slides down along the two sides of the boss (4) and is sprayed through the spray pipe (5) towards the two sides of the boss (4) and the bottom of the crushing roller (3). The turbid liquid washed along the boss (4) is passed into the lower stirring cylinder (102) through the discharge port (6). Large particles or impurities that are not fully crushed and washed are intercepted by the filter screen. At the same time, the scraper (7) rotates back and forth in the axial direction inside the crushing cylinder (101), driving one of the scraper plates (8) to scrape the filter screen and sprinkle the scraped material down onto the crushing roller through the open opening (80). (3) When the scraper (7) rotates to the other side of the boss (4), the scraper assembly is pushed by the side end of the boss (4) so ​​that another scraper (8) rotates to be parallel to the scraper (7). The scraper (8) parallel to the scraper (7) scrapes the filter screen on the other side of the boss (4) and the scraped material is sprinkled down onto the crushing roller (3) along the open opening (80) to reduce the accumulation of material on the filter screen and further improve the crushing and washing efficiency. The washing liquid in the mixing drum (102) is stirred by the stirring shaft (103) and further crushed and washed before being sent to the next stage of pressure filtration and washing operation. The iron oxide filter cake obtained by multi-stage pressure filtration separation achieves the removal of impurities from battery-grade iron oxide.

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