Disc filtering and washing device, graphite purification device and purification method

Abstract

The disc filtering and washing device comprises a material pool, a rotating disc, an auxiliary dewatering device and a discharging device, the rotating disc comprises a rack, a rotating shaft rotationally assembled on the rack, a motor driving the rotating shaft to rotate and a plurality of filter plate sets fixed to the rotating shaft and arranged in the axial direction of the rotating shaft; the opposite sides of the filter plates of the adjacent filter plate groups are uniformly provided with air holes to form adsorption sides, the turntable is sequentially provided with a material adsorption area, a first atomization washing area, a second atomization washing area, an extrusion dehydration area and a discharging area along the rotating direction of the rotating shaft, and the turntable is arranged right above the material pool, so that the material adsorption area is arranged in the material pool; the rotary disc is provided with atomization spraying devices in the first atomization washing area and the second atomization washing area, the rotary disc is provided with an auxiliary dewatering device in the extrusion dewatering area, and the rotary disc is provided with a discharging device in the discharging area. The washing device is good in washing effect and high in washing efficiency, and saves labor and cost.

Description

Technical Field

[0001] The invention relates to the technical field of graphite purification, and in particular to a disc filtering and washing device, a graphite purification device and a purification method. Background Art

[0002] As the lithium battery market continues to expand, competition is becoming increasingly fierce, and the control of material costs is becoming more stringent. The purification process is a common wet purification process. Under liquid conditions, this process achieves the reaction and separation of acids, alkalis, etc. with metals to achieve the purpose of purification. This process is widely used in hydrometallurgy, carbon black purification, natural graphite purification, hard carbon purification, recycled graphite, porous carbon activated carbon and other fields. The carbon black is a conductive agent in lithium-ion batteries, and natural graphite, hard carbon, recycled graphite, porous carbon, etc. can be used as negative electrode materials for lithium-ion batteries. Therefore, the purification process is one of the key processes in the production and manufacturing process of lithium battery materials.

[0003] There are many related patents for graphite purification, and the mainstream purification processes include high temperature method, alkaline acid method, and hydrofluoric acid method. The high temperature method requires large investment and high cost, and some impurities cannot be removed. The purification time in the purification process of the alkaline acid method and the hydrofluoric acid method is long, the washing effect is poor, the production capacity is difficult to break through, the equipment investment is large, and the production line is mostly realized manually, resulting in increased labor costs and substandard product quality. The graphite purification process in the two patent documents with publication numbers CN110171825A and CN202111033032 uses a filter press equipment for pressure filtration and deacidification treatment after the primary and secondary reactions.

[0004] like Figure 1 As shown, the existing process is as follows:

[0005] 1. The existing process technology uses graphite raw materials and A acid, B acid, C acid and water to be added into a batching barrel in proportion and fully stirred.

[0006] 2. Use a pump to pump the stirred material into a primary reaction tank and heat the material with steam. The reaction time is 16-24 hours, the temperature is between 50-90°C, and the temperature is circulated until the reaction is completed.

[0007] 3. After the reaction is completed, the material is separated into solid and liquid by a filter press and then washed with pure water for 30-60 minutes. It takes 3 hours to wash one sheet of material each time, and 2 tons of material are washed each time. The time is long, the efficiency is low, and the yield is low, which seriously restricts the output.

[0008] 4. The dehydrated material enters the secondary batching barrel, and A acid, B acid and water are added in proportion for secondary reaction. The reaction lasts for 8-16 hours. The material is heated by steam, and the temperature is controlled between 50-90°C. The temperature is circulated until the reaction is completed.

[0009] 5. After the secondary reaction is completed, the solid-liquid separation is performed again with a filter press and then washed for 30-60 minutes. When the pH value is neutral, it enters the 3rd batching tank for pulping.

[0010] 6. After pulping is completed, it is pumped to the transition tank and then flows into the centrifuge for water washing. The washing time is 40-80 minutes. After washing, it is dehydrated to keep the moisture content ≤20. After completion, it is peeled and bagged.

[0011] 7. After bagging, the materials are put into the flash evaporation process for drying and dehydration, and then screened to remove the magnetic packaging.

[0012] Therefore, it can be seen that the existing graphite purification process has the following disadvantages:

[0013] 1. The material reaction time is long, resulting in low production efficiency;

[0014] 2. Large amount of acid is used, resulting in large amount of acidic sewage and high sewage treatment cost;

[0015] 3. The filter press washing equipment is backward, with low automation, slow feeding, long washing time, large water consumption and low efficiency. A production line with an annual output of 20,000 tons requires 5 filter presses, 2 of which require 3 manual workers to shovel materials, resulting in high labor costs;

[0016] 4. The output of a single 1600 centrifuge is low, with a daily production capacity of only 7 tons. A production line with an annual output of 20,000 tons requires 10 centrifuges, resulting in large equipment investment, high maintenance costs, low yield, and low automation. Three centrifuges require two employees, resulting in high labor costs.

[0017] 5. Due to the structure of the equipment, the material is between the two filter plates, which makes it impossible to effectively wash out the impurity ions when washing the material. Therefore, it is necessary to use a centrifuge to wash it twice to meet the quality requirements. Summary of the invention

[0018] The present invention solves the deficiencies of the prior art and provides a disc filter washing device, a graphite purification device and a purification method which have good washing effect, high washing efficiency, labor saving and cost saving.

[0019] To achieve the above-mentioned purpose, the present invention first proposes a disc filter washing device, including a material pool, a turntable, an auxiliary dehydration device and a discharge device. The turntable includes a frame, a rotating shaft rotatably mounted on the frame, a motor driving the rotating shaft to rotate, and a plurality of filter plate groups fixed on the rotating shaft and arranged along the axial direction of the rotating shaft. Each filter plate group includes a plurality of filter plates evenly arranged around the rotating shaft, the spacing between adjacent filter plate groups is the same, and the filter plates of adjacent filter plate groups are covered with air permeable holes on opposite sides to form an adsorption side; a first air channel connected to the adsorption side is provided inside the filter plate, and a second air channel is provided inside the rotating shaft. The first air channel is connected to the adsorption side. The first atomizing washing zone and the second atomizing washing zone are connected, and the second air channel is connected to the inlet of the vacuum filter through a pipeline; the turntable is provided with a material adsorption zone, a first atomizing washing zone, a second atomizing washing zone, an extrusion dehydration zone and a discharge zone in sequence along the rotation direction of the shaft, the material adsorption zone is arranged on the bottom side of the turntable, the extrusion dehydration zone is arranged on the top side of the turntable, and the turntable is installed directly above the material pool so that the material adsorption zone is placed in the material pool; the turntable is provided with an atomizing spray device in the first atomizing washing zone and the second atomizing washing zone, the turntable is provided with an auxiliary dehydration device in the extrusion dehydration zone, and the turntable is provided with a discharge device in the discharge zone.

[0020] In the above embodiment, the filter plate is fan-shaped, and a plurality of filter plates in the same filter plate group are surrounded to form a circular ring perpendicular to the rotating shaft.

[0021] In the above embodiment, the atomizing spray device includes a first spray device and a second spray device, the first spray device is arranged in the first atomizing washing area, and the second spray device is arranged in the second atomizing washing area. The first spray device and the second spray device have the same structure and both include multiple groups of atomizing nozzle groups. The number and position of the atomizing nozzle groups match the number and position of the filter plate groups. Each group of atomizing nozzle groups includes two atomizing nozzles arranged on both sides of the filter plate and facing the two adsorption sides of the filter plate respectively. The liquid inlet of the atomizing nozzle is connected to the main pipeline, and the main pipeline is connected to the liquid storage container through a pump.

[0022] In the above embodiment, the unloading device includes multiple scraper groups, the number and position of the scraper groups match the number and position of the filter plate groups, each scraper group includes scrapers respectively arranged on the two adsorption sides of the filter plate, one end of the scraper is a fixed end, and the other end is a blade end, the fixed end of the scraper is slidably mounted on a slide rail, the slide rail is fixed on the frame and parallel to the axis of the rotating shaft, the scraper locks the relative position of the scraper and the slide rail through a locking device, and the distance between the blade end of the scraper and the adsorption side of the filter plate is less than the minimum particle diameter of the material.

[0023] In the above embodiment, the auxiliary dehydration device includes a pressure plate group and a hydraulic cylinder. The number and position of the pressure plate groups match the number and position of the filter plate groups. Each pressure plate group includes pressure plates respectively arranged on the two adsorption sides of the filter plate. Two hydraulic cylinders are fixed on the frame. One hydraulic cylinder controls all the pressure plates on one side of the filter plate in all the pressure plate groups, and the other hydraulic cylinder controls all the pressure plates on the other side of the filter plate in all the pressure plate groups, so that the two pressure plates on both sides of the filter plate are driven by the two hydraulic cylinders to move closer to or away from each other.

[0024] The present invention also includes a graphite purification device including a disc filter washing device, including a primary batching tank, a primary reaction tank, a primary disc filter washing device, a pulping batching unit, a secondary reaction tank, a secondary disc filter washing device, a drying device and a screening and demagnetizing packaging paper device; the primary disc filter washing device and the secondary disc filter washing device have the same structure and both use the disc filter washing device, the discharge port of the primary batching tank is connected to the feed port of the primary reaction tank through a first pipeline, a first pump is installed on the first pipeline, the discharge port of the primary reaction tank is connected to the feed port of the primary disc filter washing device through a second pipeline The second pipeline is connected, a second pump is installed on the second pipeline, the outlet of the unloading area of ​​the primary disc filter and washing device is connected to the feed port of the pulping and batching unit, the discharge port of the pulping and batching unit is connected to the feed port of the secondary reaction tank through the third pipeline, a third pump is installed on the third pipeline, the discharge port of the secondary reaction tank is connected to the feed port of the secondary disc filter and washing device material pool through the fourth pipeline, a fourth pump is installed on the fourth pipeline, the outlet of the unloading area of ​​the secondary disc filter and washing device is connected to the feed port of the drying device through the first conveying mechanism, and the discharge port of the drying device is connected to the screening and demagnetization packaging paper equipment through the second conveying mechanism.

[0025] In the above embodiment, the gas outlets of the primary batching tank, the primary reaction tank, the pulping batching unit and the secondary reaction tank are respectively connected to the feed of the acid mist absorption tower through pipelines.

[0026] The present invention also includes a graphite purification method using the above graphite purification device, comprising the following specific steps:

[0027] S1. Primary batching: Add graphite raw material, acid and water into the primary batching tank according to the set proportions, and stir them fully through the stirring device;

[0028] S2, primary reaction: using a first pump to transport the mixture after stirring in the primary batching tank to the primary reaction tank, continue stirring in the primary reaction tank, and use steam to heat the mixture in the primary reaction tank. The temperature of the mixture is controlled between 80 and 90° C., the reaction time is 9 to 16 hours, and then the mixture is kept warm for 8 hours;

[0029] S3, primary filtering and washing: using a second pump to transport the mixed material from the primary reaction tank to the material pool of the primary disc filtering and washing device, and using the primary disc filtering and washing device to wash the material;

[0030] S4, secondary batching: the material coming out of the unloading area of ​​the primary disc filter washing device enters the pulping batching unit, and acid and water are added to the pulping batching unit according to the set ratio for full stirring;

[0031] S5, secondary reaction: the mixture in the pulping batching unit is transported to the secondary reaction tank by a third pump, stirred again in the secondary reaction tank, and then the mixture in the secondary reaction tank is heated by steam, the temperature is controlled between 65 and 80° C., the reaction time is 3 to 8 hours, and the temperature is kept for 2 hours;

[0032] S6, secondary washing: after the secondary reaction is completed, the material is transported to the material pool of the secondary disc filter washing device by the fourth pump, and the material is washed by the secondary disc filter washing device;

[0033] S7. The materials in the discharge area of ​​the secondary disc filter washing device are transported to the flash evaporation process through the conveying mechanism for drying and dehydration, and then screened, demagnetized and finally packaged.

[0034] In the above embodiment, in step S2, the specific stirring method of the primary reaction tank is: the stirring speed is 25r / min~40r / min, so that the material is fully contacted with the acid for reaction, and after stirring for 6 hours, the stirring speed is adjusted to 50r / min~70r / min.

[0035] In the above embodiment, in step S5, the stirring speed in the secondary reaction tank is 50 r / min to 70 r / min.

[0036] With the above structure, the present invention has the following advantages:

[0037] 1. The present invention adopts a disc filter washing device, which can shorten the reaction time and improve production efficiency; specifically: the material is adsorbed on the filter plate by negative pressure through the filter plate, and the material thickness is between 0.5-1cm, ensuring that the subsequent washing is more thorough and the washing effect is improved.

[0038] By setting an atomizing nozzle outside the filter plate and spraying low-concentration acid and / or pure water on the material layer adsorbed on the filter plate through the atomizing nozzle, the same effect of stirring and slurrying in the tank as in the prior art can be achieved. The important thing is that there is no need for stirring and a turntable, which makes the washing speed faster and more efficient.

[0039] Extrusion dehydration device: After the material outside the filter plate is washed twice, the moisture content is relatively high. Auxiliary dehydration is performed through pressing plate extrusion dehydration to reduce the moisture content of the material to less than 20%. The pressing plate is made of PPH material to avoid contamination of the material.

[0040] Discharging device: After the water is squeezed out of the material, the turntable rotates to the discharging device area, and the scrapers on both sides of the turntable are used to peel off the material on the filter plate. The scraper itself is fixed on the frame, and the relative movement between the filter plate and the scraper is achieved through the rotation of the turntable, so that the material is peeled off and falls into the filter. No additional power is required, which makes the structure simple and the cost low.

[0041] 2. The use of disc filter washing devices to replace filter presses and centrifuges has the following advantages: ① The daily production capacity of a single device can reach 30-60 tons, which is more than 1 times more efficient than the traditional filter press. ② The equipment has a high degree of automation, and only one person is needed to operate two devices. ③ The washing effect is good. The equipment uses high-pressure atomizing nozzles for elution, which has a better washing effect on the material and can fully remove impurity ions, thereby reducing the washing time and material reaction time.

[0042] 3. The elution effect can be enhanced by spraying. On the one hand, it can reduce the amount of acid used, thereby reducing the cost of sewage treatment and improving the company's benefits. On the other hand, the elution has a more thorough washing effect on the material and can fully remove impurity ions, thereby reducing the washing time, saving water resources and reducing sewage treatment costs and material reaction time.

[0043] 4. The filter plate is made of ceramic filter plate, which has a higher mesh count and is more durable than ordinary filter cloth. It can reduce the loss of materials during washing, thereby improving the recovery rate.

[0044] 5. After reducing the filter press and centrifuge, the investment and maintenance costs of the equipment are greatly reduced, which in turn reduces the number of maintenance personnel, reduces labor costs, and improves the company's benefits.

[0045] In summary, the present invention enables the graphite purification device to achieve a daily production capacity of 30-50 tons, which is more than 1 times more efficient than the traditional filter press, improving production capacity. In addition, the disc filter washing device is used, and there is no need for manual shoveling. Only one person is needed to operate two devices. Calculated based on an annual output of 20,000 tons, the number of people on a single production line can be reduced from 16 to 8, greatly reducing labor costs. Calculated based on an annual output of 20,000 tons, the design of using existing filter presses and centrifuges for washing requires 5 filter presses and 10 centrifuges to meet the use requirements. There are many devices, high procurement costs, and high maintenance costs. However, the present invention only requires 5 units to complete the task, which is relatively low in investment and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is the process flow chart of existing graphite purification.

[0047] Figure 2 The graphite purification process flow chart of the present invention.

[0048] Figure 3 It is a structural schematic diagram of the disc filter washing device of the present invention.

[0049] Figure 4 It is a schematic structural diagram of the turntable of the present invention.

[0050] Figure 5 It is a schematic diagram of the structure of the filter plate of the present invention.

[0051] Figure 6 It is a schematic diagram of the structure of the atomizing nozzle of the present invention.

[0052] In the attached drawings: 1. primary batching tank; 2. primary reaction tank; 3. primary disc filter and washing device; 4. pulping batching unit; 5. secondary reaction tank; 6. secondary disc filter and washing device; 7. drying device; 8. screening and demagnetization packaging paper equipment; 31. turntable; 311. rotating shaft; 312. filter plate; 313. material adsorption area; 314. first atomization washing area; 315. second atomization washing area; 316. extrusion dehydration area; 317. unloading area; 32. auxiliary dehydration device; 321. pressing plate; 322. hydraulic cylinder; 33. unloading device; 331. scraper; 332. slide rail; 34. material pool; 35. atomization spray device; 351. first spray device; 352. second spray device; 353. atomization nozzle. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0055] like Figure 3As shown, a disc filter washing device comprises a material pool 34, a rotating disk 31, an auxiliary dehydration device 32 and a discharge device 33. The rotating disk 31 comprises a frame, a rotating shaft 311 rotatably mounted on the frame, a motor driving the rotating shaft 311 to rotate, and a plurality of filter plate groups fixed on the rotating shaft 311 and arranged axially along the rotating shaft 311. Each filter plate group comprises a plurality of filter plates 312 evenly arranged around the rotating shaft 311. The spacing between adjacent filter plate groups is the same. The filter plates 312 of adjacent filter plate groups are covered with air holes on opposite sides to form an adsorption side. In this embodiment, the filter plate is made of ceramic filter plate. The spacing between adjacent filter plates 312 in the same filter plate group is the same. A first air channel connected to the adsorption side is provided inside the filter plate 312. A second air channel is provided inside the rotating shaft 311. The first air channel is connected to the second air channel. The second air channel is connected to the inlet of the vacuum filter through a pipeline.

[0056] like Figure 5 As shown, the turntable 31 is provided with a material adsorption zone 313, a first atomizing washing zone 314, a second atomizing washing zone 315, an extrusion dehydration zone 316 and a discharge zone 317 in sequence along the rotation direction of the rotating shaft 311. Specifically, the material adsorption zone 313 is arranged at the bottom side of the turntable 31, and the extrusion dehydration zone 316 is arranged at the top side of the turntable 31. The turntable 31 is installed directly above the material pool 34, so that the material adsorption zone 313 is placed in the material pool 34; the turntable 31 is provided with an atomizing spray device in the first atomizing washing zone 314 and the second atomizing washing zone 315, the turntable 31 is provided with an auxiliary dehydration device 32 in the extrusion dehydration zone 316, and the turntable 31 is provided with a discharge device in the discharge zone 317;

[0057] In this embodiment, the filter plate 312 is fan-shaped, and multiple filter plates in the same filter plate group are surrounded to form a ring perpendicular to the rotating shaft 311;

[0058] like Figure 6 As shown, the atomizing spray device includes a first spray device 351 and a second spray device 352, wherein the first spray device 351 is arranged in the first atomizing washing zone 314, and the first spray device 351 is used to spray dilute hydrochloric acid, and the second spray device 352 is arranged in the second atomizing washing zone 315, and the second spray device 352 is used to spray pure water; the first spray device 351 and the second spray device 352 have the same structure and both include a plurality of atomizing nozzle groups, and the number and position of the atomizing nozzle groups match the number and position of the filter plate groups, and each atomizing nozzle group includes two atomizing nozzles 353 arranged on both sides of the filter plate 312 and facing the two adsorption sides of the filter plate 312 respectively, and the liquid inlet of the atomizing nozzle 353 is connected to the main pipeline, and the main pipeline is connected to the liquid storage container through a pump;

[0059] The unloading device includes a plurality of scraper groups, the number and position of the scraper groups match the number and position of the filter plate groups, each scraper group includes a scraper 331 respectively arranged on the two adsorption sides of the filter plate 312, in the present embodiment, the scraper is made of titanium alloy, one end of the scraper 331 is a fixed end, and the other end is a blade end, the fixed end of the scraper 331 is slidably mounted on a slide rail 332, the slide rail 332 is fixed on the frame, and the relative position of the scraper and the slide rail 332 is locked by a locking device, the slide rail 332 is axially parallel to the rotating shaft 311, the distance between the scraper 331 and the filter plate 312 can be adjusted by the slide rail 332 to avoid damaging the filter plate surface, the locking device can be a combination of a pin hole and a pin shaft, or a stepless adjustable locking device in the prior art can be used, the distance between the blade end of the scraper 331 and the adsorption side of the filter plate 312 is less than the minimum particle diameter of the material, thereby ensuring that the material can be scraped off the filter plate surface.

[0060] like Figure 4 As shown, the auxiliary dehydration device 32 includes a pressure plate group and a hydraulic cylinder 322. The number and position of the pressure plate groups match the number and position of the filter plate groups. Each pressure plate group includes pressure plates 321 respectively arranged on the two adsorption sides of the filter plate 312. Two hydraulic cylinders 322 are fixed on the frame. One hydraulic cylinder controls the pressure plates on one side of the filter plate in all pressure plate groups, and the other hydraulic cylinder controls the pressure plates on the other side of the filter plate in all pressure plate groups. Specifically, it also includes two connecting rods, which are arranged parallel to the rotating shaft 311. Both ends of the connecting rod are slidably installed on the frame. The connecting rod is driven by the hydraulic cylinder to move axially and is in the filter. All the pressing plates on one side of the plate are installed on one connecting rod, and all the pressing plates on the other side of the filter plate are installed on another connecting rod, so that the two hydraulic cylinders are used to control the linkage of all the filter plates, so that the two pressing plates 321 on both sides of the filter plate 312 are driven by the two hydraulic cylinders 322 to move closer to or away from each other, thereby realizing the squeezing and dehydration of the material on the filter plate 312. When the hydraulic cylinder 322 is working, it drives the pressing plates 321 on both sides of the filter plate 312 to squeeze, so as to achieve the effect of auxiliary dehydration. The pressing plate 321 is made of PPH material, and the side in contact with the material is made of soft plastic to avoid contamination of the material;

[0061] The device utilizes the rotating action of the turntable 31 to sequentially realize adsorption, pickling, water washing, dehydration and unloading of the material. Specifically, through the cooperation of the vacuum filter and the filter plate 312, when the filter plate 312 enters the material pool 34, the vacuum is utilized to adsorb the material on the surface of the filter plate 312, so that the filter plate 312 adsorbs the solid material. By controlling the suction force, it is ensured that the thickness of the material adsorbed on the filter plate 312 meets the requirements of subsequent rapid pickling and water washing (in this embodiment, the material adsorption thickness on the filter plate 312 is preferably between 0.5-1 cm), and then the filter plate 312 enters the first atomizing washing area 314 and the second atomizing washing area 315. By spraying the atomizing nozzle at a close distance and facing the material, the amount of acid used can be reduced, thereby reducing the treatment of sewage. The processing cost is reduced, and the impurity ions can be fully removed, thereby reducing the washing time and the material reaction time, and ensuring the efficiency of pickling and water washing; then enter the extrusion dehydration area 316, in this area, the turntable 31 needs to be controlled to stop, so that the pressing plate 321 can squeeze and dehydrate the material on the filter plate 312, and at the same time, the stop of the turntable 31 at this time cooperates with the position of the previous spraying to improve the spraying effect; after the dehydration is completed, enter the unloading area, separate the material from the filter plate 312, and enter the subsequent process; adopting the above structure, the efficiency of filtering and washing of graphite in the purification process is improved, and the daily production capacity of a single device can reach 30-60 tons, which is more than 1 times higher than the efficiency of the traditional filter press, and the equipment has a high degree of automation, and only one person is needed to operate two devices.

[0062] like Figure 2 As shown, the present invention also includes a graphite purification device, including a primary batching tank 1, a primary reaction tank 2, a primary disc filter washing device 3, a pulping batching unit 4, a secondary reaction tank 5, a secondary disc filter washing device 6, a drying device 7 and a screening and demagnetizing packaging paper device 8; the primary disc filter washing device 3 and the secondary disc filter washing device 5 have the same structure and both adopt the above-mentioned Figure 3The disc filter washing device shown, the discharge port of the primary dosing tank 1 is connected to the feed port of the primary reaction tank 2 through a first pipeline, a first pump is installed on the first pipeline, the discharge port of the primary reaction tank 2 is connected to the feed port of the material pool of the primary disc filter washing device 3 through a second pipeline, a second pump is installed on the second pipeline, the outlet of the discharge area 317 of the primary disc filter washing device 3 is connected to the feed port of the pulping dosing unit 4, the discharge port of the pulping dosing unit 4 is connected to the feed port of the secondary reaction tank 5 through a third pipeline, a third pump is installed on the third pipeline, the discharge port of the secondary reaction tank 5 is connected to the feed port of the material pool of the secondary disc filter washing device 6 through a fourth pipeline, a fourth pump is installed on the fourth pipeline, The outlet of the discharge area 317 of the secondary disc filter washing device 6 is connected to the feed port of the drying device 7 through a first conveying mechanism, and the discharge port of the drying device 7 is connected to the screening and demagnetization packaging paper equipment 8 through a second conveying mechanism; the drying device 7 adopts a flash drying device, and the screening and demagnetization packaging paper equipment 8 includes a vibrating screen, a demagnetizer and a packaging machine connected in sequence according to the process. The flash drying device, vibrating screen, demagnetizer and packaging machine are all existing equipment, and their structures are not described in detail here. In this embodiment, the first pump, the second pump, the third pump and the fourth pump are all centrifugal pumps, and the gas outlets of the primary dosing tank 1, the primary reaction tank 2, the pulping dosing unit 4 and the secondary reaction tank 5 are respectively connected to the feed of the acid mist absorption tower 9 through pipelines.

[0063] The specific process flow of the graphite purification method of the present invention is as follows:

[0064] Preparation work before production: Test the incoming graphite and set the ratio of graphite raw materials, acid and water according to the quality of graphite.

[0065] In this embodiment, the acid ratio includes but is not limited to the following combinations:

[0066] Combination A is (hydrochloric acid, hypochlorous acid, hydrofluoric acid), combination B is (hydrochloric acid, sulfuric acid, hydrofluoric acid), combination C is (sulfuric acid, nitric acid, hydrofluoric acid), combination D is (hydrochloric acid, nitric acid, hydrofluoric acid), combination E is (hydrochloric acid, formic acid, hydrofluoric acid), combination F is (sulfuric acid, formic acid, hydrofluoric acid), combination G is (hydrochloric acid, hydrofluoric acid), combination H is (sulfuric acid, hydrofluoric acid), combination I is (hydrochloric acid, nitric acid), and combination J is (hydrochloric acid, hydrofluoric acid).

[0067] S1. Primary batching: According to the setting, graphite raw material, acid and water are added into the primary batching tank respectively, and fully stirred by the stirring device;

[0068] S2, primary reaction: Use the first pump to transport the mixed material after stirring in the primary batching tank to the primary reaction tank, and stir it again in the primary reaction tank. First, control the stirring speed at 25r / min-40r / min to allow the material to fully contact with the acid for reaction. After stirring for 6 hours, adjust the stirring speed to 50r / min-70r / min to better separate the impurities from the graphite. Then, use steam to heat the mixed material in the primary reaction tank. The temperature of the mixed material is controlled between 80 and 90°C. The reaction time is 9 to 16 hours, and then keep warm for 8 hours.

[0069] S3, primary filtering and washing: using a second pump to transport the mixed material from the primary reaction tank to the material pool of the primary disc filtering and washing device, and using the primary disc filtering and washing device to wash the material;

[0070] Specifically: the filter plate is driven by the rotation of the turntable, and the negative pressure of the filter plate is used to adsorb the material in the material pool onto the filter plate to achieve rapid solid-liquid separation;

[0071] When the rotating disk drives the filter plate to leave the material adsorption area and rotate to the first atomization washing area, the material on the filter plate is sprayed with dilute hydrochloric acid through the atomization nozzle in the first atomization washing area for elution (in this embodiment, dilute hydrochloric acid generally refers to dilute hydrochloric acid with a concentration of 2%). Since the hydrogen ions in the dilute hydrochloric acid can react with the impurity ions in the material, the impurity ions attached to the surface of the material can be transferred to the solution, and then the solution and the material can be quickly separated by negative pressure, achieving a more ideal washing effect;

[0072] When the turntable drives the filter plate to leave the first atomizing washing area and rotate to the second atomizing washing area, the atomizing nozzle in the second atomizing washing area sprays pure water on the material on the filter plate for washing, consolidating the washing effect and washing the pH value of the material to neutral;

[0073] When the turntable drives the filter plate to leave the second atomization washing area and rotate to the extrusion dehydration area, the pressure plates on both sides of the filter plate are used to squeeze the material on the filter plate to assist dehydration. The auxiliary dehydration device includes a hydraulic cylinder and a pressure plate. When the hydraulic cylinder is working, the pressure plates on both sides of the filter plate are driven to squeeze the filter plate to achieve the effect of auxiliary dehydration. The pressure plate is made of PPH material, and the side in contact with the material is made of soft plastic to avoid contamination of the material; in the extrusion dehydration area, the control turntable stops and continues to rotate after the extrusion is completed.

[0074] When the turntable drives the filter plate to the unloading area, the material is peeled off from the filter plate by the unloading device; the unloading device uses scrapers made of titanium alloy fixed on both sides of the filter plate. The scrapers are installed on the slide rails, which are parallel to the axis of the turntable. The distance between the scraper and the filter plate can be adjusted through the slide rails to avoid damaging the surface of the filter plate.

[0075] When the above-mentioned disc filter washing device is used to wash the material, the material is adsorbed on the surface of the filter plate by negative pressure. The thickness of the material adsorbed by the filter plate can be achieved by adjusting the pressure. During the washing process, the material can be better adsorbed on the filter plate due to the effect of the leaching water, and after being squeezed, the material is tighter, ensuring that the material does not fall off when entering the unloading area. The washing process is a continuous intermittent process with short time and high efficiency. It uses a high-pressure atomizing nozzle for leaching, which consumes less water and has a better washing effect. A special filter plate is used, with less material loss and high yield. This equipment has a high degree of automation, which can reduce labor input and further improve efficiency.

[0076] S4. Secondary batching: the material coming out of the unloading area of ​​the primary disc filter washing device enters the pulping batching unit, and acid and water are added to the pulping batching unit according to the set ratio for sufficient stirring.

[0077] S5. Secondary reaction: Use the third pump to transport the mixture in the pulping batching unit to the secondary reaction tank, stir it again in the secondary reaction tank, and control the stirring speed at 50r / min~70r / min. Then use steam to heat the mixture in the secondary reaction tank, and control the temperature between 65 and 80°C. The reaction time is 3 to 8 hours, and the heat preservation is 2 hours.

[0078] S6, secondary washing: after the secondary reaction is completed, the material is transported to the material pool of the secondary disc filter washing device by the fourth pump, and the material is washed again by the secondary disc filter washing device; the structure of the secondary disc filter washing device is the same as that of the primary disc filter washing device, and the specific washing process is not repeated;

[0079] S7. The materials in the discharge area of ​​the secondary disc filter washing device are bagged and then sent to the flash evaporation process for drying and dehydration, screening, demagnetization and finally packaging.

[0080] The specific embodiment of graphite purification according to the above-mentioned graphite purification method is as follows:

[0081] Embodiment 1:

[0082] According to the quality of the incoming materials, acid combination B is selected, wherein hydrochloric acid, sulfuric acid, hydrofluoric acid and water are added into the primary batching tank in a ratio of 3:1:1:5 to be quickly mixed and stirred with the graphite raw material. After the stirring is completed, the materials are transported to the primary reaction tank, and the stirring is continued in the primary reaction tank. The stirring speed is controlled at 25r / min~40r / min, and adjusted to 50r / min~70r / min after stirring for 6 hours; then, it is heated to 80~90℃ with steam, kept warm for 8 hours, and reacted in the primary reaction tank for 14 hours.

[0083] After the primary reaction is completed, the material is transported to the primary disc filter washing device for solid-liquid separation and washing. After washing, the batching and pulping area of ​​the primary disc filter washing device is used to select the acid of combination I, in which hydrochloric acid, nitric acid and water are added to the pulping batching unit in a ratio of 3:1:6 and stirred again with the material, and then transported to the secondary reaction tank after stirring.

[0084] In the secondary reaction tank, the material is heated to 65-80℃ by steam, kept warm for 2 hours, the stirring speed is controlled at 50r / min-70r / min, and the reaction is carried out in the tank for 6 hours. After the reaction, the centrifugal pump transports the material to the secondary disc filter washing device for solid-liquid separation and washing. According to the quality requirements, the disc filter washing can be carried out 3 times. After washing, the material is packed in tons for sampling and testing. The qualified materials are flash dried to dry the moisture to 0.1%, then screened, demagnetized, and finally packaged with a fixed weight.

[0085] Embodiment 2:

[0086] According to the quality of the incoming materials, select the acid of combination B, in which hydrochloric acid, sulfuric acid, hydrofluoric acid and water are added into the primary batching tank in a ratio of 2.5:1:1:4.5 to mix and stir quickly with the graphite raw materials, and then transport the materials to the primary reaction tank. The stirring speed is controlled at 25r / min~40r / min, and adjusted to 50r / min~70r / min after stirring for 6 hours. Then use steam to heat to 80~90℃, keep warm for 8 hours, and react in the tank for 12 hours.

[0087] After the primary reaction is completed, the material is transported to the primary disc filter washing machine for solid-liquid separation and washing. After washing, the batching and pulping area of ​​the primary disc filter washing device is used to select the acid of combination I, in which hydrochloric acid, nitric acid and water are added to the pulping batching unit in a ratio of 2:1:7 and stirred again with the material, and then transported to the secondary reaction tank after stirring.

[0088] In the secondary reaction tank, the material is heated to 65-80℃ by steam, kept warm for 2 hours, the stirring speed is controlled at 50r / min-70r / min, and the reaction is carried out in the tank for 4 hours. After the reaction, the centrifugal pump transports the material to the secondary disc filter washing device for solid-liquid separation and washing. According to the quality requirements, the disc filter washing can be carried out 3 times. After washing, the material is packed in tons for sampling and testing. The qualified materials are flash dried to dry the moisture to 0.1%, then screened for demagnetization, and finally packaged with a fixed weight.

[0089] Comparative Example 1:

[0090] Comparative Example 1 adopts the existing process flow mentioned in the background technology, such as Figure 1As shown, select the acid of combination B, wherein hydrochloric acid, sulfuric acid, hydrofluoric acid and water are added into the primary batching tank in a ratio of 3:1:1:5 to mix and stir with the graphite raw material quickly, and then use a diaphragm pump to transport the material to the primary reaction tank. The stirring speed is controlled at 25r / min~40r / min, and adjusted to 50r / min~70r / min after stirring for 6 hours. Use steam to heat to 80~90℃, keep warm for 8 hours, and react in the tank for 18 hours.

[0091] After the primary reaction is completed, the material is transported to the primary filter press for solid-liquid separation and washing. After washing, the material is manually shoveled off the filter plate and put into the secondary batching barrel. Select the acid combination I, in which hydrochloric acid, nitric acid and water are added to the secondary batching barrel in a ratio of 3:1:6 and stirred again with the material. After stirring, it is transported to the secondary reaction tank with a centrifugal pump.

[0092] In the secondary reaction tank, the material is heated to 65-80℃ by steam, kept warm for 2 hours, and the stirring speed is controlled at 50r / min-70r / min. The reaction is carried out in the secondary reaction tank for 12 hours. After the reaction is completed, the material is transported to the secondary filter press by a centrifugal pump for solid-liquid separation and washing. The pH value is washed to neutral. The material is shoveled from the filter plate to the tertiary batching barrel, and water is added at a ratio of 1:1.2 for stirring. After stirring, it is transported to the centrifuge for washing. After the centrifugal washing is completed, it is taken out in a ton bag. The material is sampled and tested, and the qualified materials are flash dried to dry the moisture to 0.1%, then screened for demagnetization, and finally packaged by fixed weight.

[0093] Comparative Example 2:

[0094] Comparative Example 2 also adopts the existing process flow mentioned in the background technology, such as Figure 1 As shown, select the acid of combination D, in which hydrochloric acid, nitric acid, hydrofluoric acid and water are added into the primary batching tank in a ratio of 3:2:1:4 for rapid mixing and stirring, and then the materials are transported to the primary reaction tank by a diaphragm pump. The stirring speed is controlled at 25r / min~40r / min, and adjusted to 50r / min~70r / min after stirring for 6 hours. Heat to 80~90℃ with steam, keep warm for 8 hours, and react in the tank for 17 hours.

[0095] After the primary reaction is completed, the material is transported to the primary filter press for solid-liquid separation and washing. After washing, the material is manually shoveled off the filter plate and put into the secondary batching barrel. Select the acid of combination I, in which hydrochloric acid, nitric acid and water are added to the secondary batching barrel in a ratio of 3:2:5 and stirred again with the material. After stirring, it is transported to the secondary reaction tank with a centrifugal pump.

[0096] In the secondary reaction tank, steam is used to heat the material to 65-80℃, and the temperature is kept for 2 hours. The stirring speed is controlled at 50r / min-70r / min, and the reaction is carried out in the tank for 11 hours. After the reaction is completed, the material is transported to the secondary filter press by a centrifugal pump for solid-liquid separation and washing. The pH value is washed to neutral, and the material is shoveled from the filter plate to the tertiary batching barrel, and water is added at a ratio of 1:1.2 for stirring. After stirring, it is transported to the centrifuge for washing. After the centrifugal washing is completed, it is taken out with a ton bag. Samples are taken for testing, and qualified materials are flash dried to dry the moisture to 0.1%, then screened for demagnetization, and finally packaged with a fixed weight.

[0097] The comparative analysis of the examples and comparative examples is shown in the table below:

[0098]

[0099] From the data in the above table, it can be seen that the trace element results of the materials washed by the disc filter of the present invention are better than those washed by the filter press and centrifuge. The production capacity, washing, maintenance and cost of the customized disc filter washing machine are all superior to those of the traditional filter press and centrifuge.

[0100] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A disc filter washing device, characterized in that: The invention comprises a material pool (34), a rotating disk (31), an auxiliary dehydration device (32) and a discharge device (33); the rotating disk (31) comprises a frame, a rotating shaft (311) rotatably mounted on the frame, a motor for driving the rotating shaft (311) to rotate, and a plurality of filter plate groups fixed on the rotating shaft (311) and arranged axially along the rotating shaft (311); each filter plate group comprises a plurality of filter plates (312) evenly arranged around the rotating shaft (311); the spacing between adjacent filter plate groups is the same; the filter plates (312) of adjacent filter plate groups are evenly covered with air holes on opposite sides to form an adsorption side; and negative pressure is provided inside the filter plates (312); the rotating disk (31) is provided with a material adsorption area (313), a first mist absorption area (314) and a second mist absorption area (315) in sequence along the rotation direction of the rotating shaft (311). The rotary disk (31) is provided with a first atomizing washing zone (314), a second atomizing washing zone (315), an extrusion dehydration zone (316) and a discharge zone (317); the material adsorption zone (313) is arranged on the bottom side of the rotary disk (31), and the extrusion dehydration zone (316) is arranged on the top side of the rotary disk (31); the rotary disk (31) is installed directly above the material pool (34), so that the material adsorption zone (313) is placed in the material pool (34); the rotary disk (31) is provided with an atomizing spray device (35) in both the first atomizing washing zone (314) and the second atomizing washing zone (315); the rotary disk (31) is provided with an auxiliary dehydration device (32) in the extrusion dehydration zone (316); and the rotary disk (31) is provided with a discharge device (33) in the discharge zone (317).

2. The disc filter washing device according to claim 1, characterized in that: The filter plate (312) is fan-shaped, and multiple filter plates in the same filter plate group are surrounded to form a circular ring perpendicular to the rotating shaft (311).

3. The disc filter washing device according to claim 1, characterized in that: The atomizing spray device (35) comprises a first spray device (351) and a second spray device (352), wherein the first spray device (351) is arranged in the first atomizing washing zone (314), and the second spray device (352) is arranged in the second atomizing washing zone (315). The first spray device (351) and the second spray device (352) have the same structure and both comprise a plurality of atomizing nozzle groups, wherein the number and position of the atomizing nozzle groups match the number and position of the filter plate groups, and each atomizing nozzle group comprises two atomizing nozzles (353) arranged on both sides of the filter plate (312) and facing the two adsorption sides of the filter plate (312) respectively, and the liquid inlet of the atomizing nozzle (353) is connected to a main pipeline, and the main pipeline is connected to a liquid storage container through a pump.

4. The disc filter washing device according to claim 1, characterized in that: The unloading device (33) comprises a plurality of scraper groups, the number and position of the scraper groups match the number and position of the filter plate groups, each scraper group comprises scrapers (331) respectively arranged on the two adsorption sides of the filter plate (312), one end of the scraper (331) is a fixed end, and the other end is a blade end, the fixed end of the scraper is slidably mounted on a slide rail (332), the slide rail (332) is fixed on the frame and axially parallel to the rotating shaft (311), the scraper (331) is locked in relative position with the slide rail (332) by a locking device, and the distance between the blade end of the scraper (331) and the adsorption side of the filter plate (312) is smaller than the minimum particle diameter of the material.

5. The disc filter washing device according to claim 1, characterized in that: The auxiliary dehydration device (32) comprises a pressing plate group and a hydraulic cylinder (322). The number and position of the pressing plate groups match the number and position of the filter plate groups. Each pressing plate group comprises pressing plates (321) respectively arranged on two adsorption sides of the filter plate (312). Two hydraulic cylinders (322) are fixed on the frame. One hydraulic cylinder (322) controls the pressing plates (321) arranged on one side of the filter plate (312) in all the pressing plate groups, and the other hydraulic cylinder (322) controls the pressing plates (321) arranged on the other side of the filter plate (312) in all the pressing plate groups, so that the two pressing plates (321) on both sides of the filter plate (312) are respectively driven by the two hydraulic cylinders (322) to move closer to or farther from each other.

6. A graphite purification device, comprising the disc filter washing device according to any one of claims 1 to 5, characterized in that: It also includes a primary batching tank (1), a primary reaction tank (2), a primary disc filter washing device (3), a pulping batching unit (4), a secondary reaction tank (5), a secondary disc filter washing device (6), a drying device (7) and a screening and demagnetizing packaging paper device (8); the primary disc filter washing device (3) and the secondary disc filter washing device (6) have the same structure and both use the disc filter washing device; the discharge port of the primary batching tank (1) is connected to the feed port of the primary reaction tank (2) through a first pipeline, a first pump is installed on the first pipeline, the discharge port of the primary reaction tank (2) is connected to the feed port of the material pool (34) of the primary disc filter washing device (3) through a second pipeline, and the first pump is installed on the first pipeline. A second pump is installed on the second pipeline, the outlet of the unloading area of ​​the primary disc filter washing device (3) is connected to the feed port of the pulping and batching unit (4), the outlet of the pulping and batching unit (4) is connected to the feed port of the secondary reaction tank (5) through a third pipeline, a third pump is installed on the third pipeline, the outlet of the secondary reaction tank (5) is connected to the feed port of the secondary disc filter washing device (6) material pool (34) through a fourth pipeline, a fourth pump is installed on the fourth pipeline, the outlet of the unloading area of ​​the secondary disc filter washing device (6) is connected to the feed port of the drying device (7) through the first conveying mechanism, and the outlet of the drying device (7) is connected to the screening and demagnetization packaging paper equipment (8) through the second conveying mechanism.

7. The graphite purification device according to claim 6, characterized in that: The gas outlets of the primary batching tank (1), the primary reaction tank (2), the pulping batching unit (4) and the secondary reaction tank (5) are respectively connected to the feed of the acid mist absorption tower through pipelines.

8. A graphite purification method using the graphite purification device according to claim 6 or 7, characterized in that: The specific steps include: S1. Primary batching: adding graphite raw material, acid and water into a primary batching tank (1) according to a set ratio, and stirring them thoroughly by a stirring device; S2, primary reaction: the mixed material after stirring in the primary batching tank (1) is transported to the primary reaction tank (2) by a first pump, stirred again in the primary reaction tank (2), and then the mixed material in the primary reaction tank (2) is heated by steam, the temperature of the mixed material is controlled between 80 and 90° C., the reaction time is between 9 and 16 hours, and then the temperature is kept for 8 hours; S3, primary filtering and washing: using a second pump to transport the mixed material from the primary reaction tank (2) to the material pool (34) of the primary disc filtering and washing device (3), and using the primary disc filtering and washing device (3) to wash the material; S4, secondary batching: the material coming out of the discharge area (317) of the primary disc filter washing device (3) enters the pulping batching unit (4), and acid and water are added in a set ratio in the pulping batching unit (4) for sufficient stirring; S5, secondary reaction: using a third pump to transport the mixture in the pulping batching unit (4) to the secondary reaction tank (5), stirring again in the secondary reaction tank (5), and then using steam to heat the mixture in the secondary reaction tank (5), the temperature is controlled between 65 and 80° C., the reaction time is between 3 and 8 hours, and the temperature is kept for 2 hours; S6, secondary washing: after the secondary reaction is completed, the material is transported to the material pool (34) of the secondary disc filter washing device (6) by a fourth pump, and the material is washed by the secondary disc filter washing device (6); S7. The materials in the discharge area (317) of the secondary disc filter washing device (6) are transported by a conveying mechanism to a flash evaporation process for drying and dehydration, followed by screening, demagnetization and finally packaging.

9. The method for purifying graphite according to claim 8, characterized in that: In step S2, the specific stirring method of the primary reaction tank (2) is: first, the stirring speed is set to 25 r / min to 40 r / min, so that the material is fully contacted with the acid for reaction; after stirring for 6 hours, the stirring speed is adjusted to 50 r / min to 70 r / min.

10. The method for purifying graphite according to claim 8, characterized in that: In step S5, the stirring speed in the secondary reaction tank (5) is 50 r / min to 70 r / min.

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