Method and equipment for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene

Abstract

The invention provides a method and equipment for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene. The method for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene comprises the steps that S1, ore pretreatment is conducted, specifically, lepidolite and spodumene with the particle size smaller than 5 mm are evenly mixed according to the mass ratio of 1: (1-3), and the mixed ore is finely ground till the particle size is smaller than 75 microns; s2, additive mixing, wherein a composite additive is added into the mixed ore obtained after fine grinding and evenly mixed with the ore, and the composite additive is composed of fluoride, sulfate and a fluxing agent; and S3, coordinated roasting, wherein the mixed materials are fed into a rotary kiln to be roasted. According to the method for producing Li2CO3 based on coordinated roasting of the lepidolite and the spodumene, the lepidolite and the spodumene are roasted in a coordinated mode, the structural and chemical property differences of the lepidolite and the spodumene are utilized, advantage complementation is achieved, the overall extraction rate of lithium is increased, compared with a single lithium extraction technology, the lithium recovery rate can be increased by 10%-20%, and the waste residue generation amount is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of Li2CO3 production, and particularly to a method and equipment for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene. BACKGROUND

[0002] Lithium carbonate (Li2CO3) is a crucial raw material in the lithium battery industry. It is the key lithium source for the preparation of positive electrode materials and electrolytes. The raw materials for the preparation of lithium carbonate usually include lepidolite and spodumene.

[0003] In the prior art, when lepidolite is used to extract lithium, its structure is complex, and the presence of alkali metal elements such as potassium and sodium leads to a long lithium extraction process, high cost, and unsatisfactory lithium recovery rate. In the extraction of lithium from spodumene, high-temperature roasting is required in the sulfuric acid method, which results in high energy consumption and severe equipment corrosion. The limestone sintering method has a low lithium recovery rate and generates a large amount of waste residue. Currently, there are few processes for simultaneously processing both types of ore, and there is a lack of efficient methods for synergistically utilizing the characteristics of both types of ore to extract lithium and produce lithium carbonate.

[0004] Therefore, it is necessary to provide a method for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene to solve the above technical problems. SUMMARY

[0005] The present application provides a method for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene, which solves the problem of the lack of efficient methods for synergistically utilizing the characteristics of both types of ore to extract lithium and produce lithium carbonate in the prior art.

[0006] To solve the above technical problems, the method for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene provided by the present application includes: S1, ore pretreatment: uniformly mixing lepidolite and spodumene with a particle size less than 5 mm in a mass ratio of 1:(1-3), and finely grinding the mixed ore to a particle size less than 75 μm; S2, additive mixing: adding a composite additive to the finely ground mixed ore and uniformly mixing it with the ore, the composite additive being composed of a fluoride, a sulfate, and a fluxing agent; S3, coordinated roasting: feeding the mixed material into a rotary kiln for roasting; S4, leaching and solid-liquid separation: after cooling, the solid product after roasting is added to a 5%-25% mass fraction sulfuric acid solution for leaching, and solid-liquid separation is achieved by filtration, obtaining a lithium-containing leaching solution and a leaching residue, wherein the liquid-solid ratio is (2-6):1; S5, leaching solution purification: adding a preset amount of hydrogen peroxide to the lithium-containing leaching solution, then adjusting the pH value of the solution to 4-5, filtering the precipitate, and finally using ion exchange resin method to remove residual impurity ions in the solution, obtaining a purified lithium-containing solution; S6, lithium carbonate preparation: adding sodium carbonate or ammonium carbonate solution to the purified lithium-containing solution, controlling the reaction pH value at 8-11, generating lithium carbonate precipitate, then after filtration, washing, drying to obtain lithium carbonate.

[0007] Preferably, the composite additive in step S2 accounts for 5%-15% of the mass of the lepidolite and spodumene mixed ore; Preferably, in step S3, the roasting is performed in a segmented heating manner, first preheating at 300-400 DEG C for 30-60 minutes to make the additive initially react with the ore, and then heating to 700-850 DEG C for 1-2 hours.

[0008] The application also provides a device for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene, which is used in the method for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene, and comprises a support 1. The leaching cylinder is detachably provided with a cylinder cover at the top, and is provided with a discharge pipe at the bottom, wherein the discharge pipe is provided with a blocking assembly, and the discharge pipe is provided with a filter inside and below the blocking assembly. The discharge cylinder is installed on the cylinder cover, and a through hole is formed in the center of the cylinder cover corresponding to the discharge port of the discharge cylinder. The stirring and discharging assembly comprises a motor, a stirring shaft, a blade and a spiral conveying piece, the motor is suspended above the discharge cylinder, one end of the stirring shaft is connected with the output shaft of the motor, the other end penetrates the discharge cylinder and the cylinder cover in sequence and extends into the inside of the leaching cylinder, the blade is installed on the stirring shaft and located in the inside of the leaching cylinder, and the spiral conveying piece is installed on the stirring shaft, and the top end of the spiral conveying piece is located in the discharge port of the discharge cylinder.

[0009] Preferably, the device for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene further comprises a lifting device, the lifting device comprises a lifting cylinder and a mounting bracket, the lifting cylinder is installed on the support and located above the motor, the mounting bracket is installed on the output end of the lifting cylinder, and the motor is installed on the mounting bracket.

[0010] Preferably, the leaching cylinder further comprises a liquid outlet pipe, and the liquid outlet pipe is installed on the side of the leaching cylinder and away from the end of the cylinder cover.

[0011] Preferably, the blocking assembly comprises a mounting box, a pushing cylinder, a connecting arm and an L-shaped sealing plate, the mounting box is installed in communication with the discharge pipe, the L-shaped sealing plate is slidingly installed in the mounting box, the pushing cylinder is installed in the mounting box, and the connecting arm connects the output end of the pushing cylinder with the L-shaped sealing plate.

[0012] Preferably, the sealing assembly further includes a pressure frame and a pusher, the pressure frame being slidably connected within the L-shaped sealing plate, the pusher connecting the pressure frame and the L-shaped sealing plate, and the pusher being used to drive the pressure frame to move vertically.

[0013] Preferably, the pusher includes a threaded sleeve, a threaded shaft, and a square shaft. The top end of the threaded sleeve passes through and is rotatably mounted on the top of the L-shaped sealing plate. The square shaft is mounted on the top end of the threaded sleeve. The threaded shaft is fixedly connected to the pressure frame. The threaded shaft is threadedly connected to the threaded sleeve. The top of the pressure frame is fitted onto the threaded sleeve. A square groove is provided at the bottom end of the stirring shaft.

[0014] Preferably, the equipment for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene further includes a pushing structure, which includes a pushing plate and an assembly plate. The pushing plate is disposed against the side wall of the discharge pipe and is located between the pressure frame and the filter element. The assembly plate is connected to the top of the pressure frame. A sleeve plate is installed at the end of the pressure frame and above the assembly plate. A slag discharge door is detachably installed on the discharge pipe and below the mounting box.

[0015] Compared with related technologies, the method for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene provided by this invention has the following beneficial effects: This invention provides a method for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene. By coordinating the roasting of lepidolite and spodumene, the differences in their structures and chemical properties are utilized to achieve complementary advantages and improve the overall lithium extraction rate. Compared with the lithium extraction process alone, the lithium recovery rate can be increased by 10%-20%. It also reduces the amount of waste residue generated, optimizes the leaching and purification process, reduces the amount of chemical reagents used, reduces environmental pollution, improves resource utilization, reduces energy consumption and reagent costs, and reduces the overall lithium extraction cost by 20%-30%. Attached Figure Description

[0016] Figure 1 A flowchart illustrating the steps of the method for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene provided by the present invention. Figure 2 A schematic diagram of the equipment for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene provided by the present invention. Figure 3 for Figure 2 The image shown is a partial cross-sectional view of an equipment for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene. Figure 4 for Figure 3 The enlarged schematic diagram of part A shown below; Figure 5The structure schematic diagram of the inside of the discharge pipe provided by the present application is shown in the figure; Figure 6 The state schematic diagram of the filter residue entering the discharge pipe provided by the present application is shown in the figure, Figure 6 (a) is the state schematic diagram of the L-shaped sealing plate opening the filter residue to enter the discharge pipe, Figure 6 (b) is the schematic diagram of the L-shaped sealing plate blocking the top of the discharge pipe and the stirring shaft sleeve being arranged on the square shaft; Figure 7 The state schematic diagram of the filter residue disc discharging the discharge pipe provided by the present application is shown in the figure, Figure 7 (a) is the state schematic diagram of the pressing frame pressing the filter residue, Figure 7 (b) is the state schematic diagram of the push plate pushing the filter residue out of the discharge pipe; Figure 8 The structure schematic diagram of the pressing structure provided by the present application is shown in the figure; Figure 9 The bottom view of the pressing structure provided by the present application is shown in the figure.

[0017] Figure mark: 1, support; 2, leaching cylinder; 21, liquid outlet pipe; 22, cylinder cover; 23, discharge pipe; 231, residue outlet; 3, lifting device; 31, lifting cylinder; 32, mounting frame; 4, stirring and discharging assembly; 41, motor; 42, stirring shaft; 43, blade; 44, screw conveying part; 421, square groove; 422, driving block; 423, key block; 5, discharging cylinder; 6, blocking assembly; 61, mounting box; 62, push cylinder; 63, connecting arm; 64, L-shaped sealing plate; 65, pressing frame; 66, pushing part; 661, threaded sleeve; 662, threaded shaft; 663, square shaft; 651, sleeve plate; 642, blocking block; 7, filter part; 8, pushing structure; 81, push plate; 82, assembly plate; 9, pressing structure; 91, threaded pipe; 92, extrusion sleeve; 93, L-shaped rod; 94, extrusion part. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0019] The application provides a method for producing Li2CO3 by coordinated roasting of lepidolite and spodumene.

[0020] For reference Figures 1 to 5 In an embodiment of the application, the method for producing Li2CO3 by coordinated roasting of lepidolite and spodumene comprises the following steps: S1, ore pretreatment: uniformly mixing lepidolite and spodumene with a particle size of less than 5 mm at a mass ratio of 1: (1-3), and finely grinding the mixed ore to a particle size of less than 75 μm; S2, additive mixing: adding a composite additive to the finely ground mixed ore and uniformly mixing the composite additive with the ore, wherein the composite additive is composed of fluoride (such as calcium fluoride), sulfate (such as sodium sulfate) and fluxing agent (such as borax); S3, coordinated roasting: feeding the mixed material into a rotary kiln for roasting; S4, leaching and solid-liquid separation: after cooling, the roasted solid product is added into a sulfuric acid solution with a mass fraction of 5% - 25% for leaching, and solid-liquid separation is achieved by filtration to obtain a lithium-containing leaching solution and a leaching residue, wherein the liquid-solid ratio is (2-6):1; S5, leaching solution purification: adding a preset amount of hydrogen peroxide to the lithium-containing leaching solution, then adjusting the pH value of the solution to 4-5, filtering the precipitate, and finally removing the residual impurity ions in the solution by using an ion exchange resin method to obtain a purified lithium-containing solution; S6, lithium carbonate preparation: adding a sodium carbonate or ammonium carbonate solution to the purified lithium-containing solution, controlling the reaction pH value to be 8-11, generating lithium carbonate precipitate, and then obtaining lithium carbonate after filtration, washing and drying.

[0021] By coordinated roasting of lepidolite and spodumene, the differences in structure and chemical properties of the two are utilized to achieve complementary advantages, improve the overall extraction rate of lithium, and increase the lithium recovery rate by 10% - 20% compared with the single lithium extraction process. In addition, the amount of waste residue is reduced, the leaching and purification processes are optimized, the amount of chemical reagents used is reduced, the pollution to the environment is reduced, the resource utilization rate is improved, the energy consumption and reagent cost are reduced, and the overall lithium extraction cost is reduced by 20% - 30%.

[0022] Specifically, during the coordinated roasting, the potassium salt (such as K2O) and fluoride (such as HF) produced by the decomposition of lepidolite at a lower temperature can penetrate into the dense structure of spodumene as a "natural fluxing agent", destroy the stability of the silicon-oxygen chain, reduce the temperature of lithium spodumene crystal transformation (α→β) (such as from 1000°C to 800-900°C), and reduce the high-temperature energy consumption. At the same time, the chain structure of spodumene can act as a "skeleton" during roasting, reducing the agglomeration of fine particles caused by the interlayer rupture of lepidolite, improving the permeability of the roasting product, and facilitating the contact of the subsequent leaching agent with lithium ions. The K+ Alternative to external sodium salt, reduce the cost of auxiliary; F - Fix Al in spodumene 3+ Reduce aluminum impurities in leaching solution, improve the purity of lithium; At the same time, Si in spodumene can react with excess Al produced by roasting of lepidolite to generate stable silicate, avoiding Al 3+ Precipitate and wrap lithium particles during leaching, ensure sufficient dissolution of lithium; And after coordination roasting, spodumene is converted into β phase which is easy to be leached by acid, and lepidolite is decomposed into easy-to-dissolve lithium salt and K, F-containing residue. During leaching, the strong acid required by spodumene can also meet the leaching of lithium in lepidolite, without the need for staged adjustment of acidity; And Ca in spodumene (if adding limestone auxiliary) can react with F - Combined with the generation of CaF2 precipitate, the problem of fluorine pollution is also solved, simplifying the process steps. In addition, the lithium of the two minerals is leached in the same system, avoiding the loss of lithium due to differences in leaching conditions when treated separately, and improving the overall recovery rate; Among them, in S5, appropriate amount of hydrogen peroxide is added to the lithium-containing leaching solution to oxidize ferrous ions to ferric ions. Then adjust the pH value of the solution to 4 - 5, so that impurities such as iron ions and aluminum ions are precipitated in the form of hydroxide, and the precipitate is removed by filtration. Then use ion exchange resin method to remove trace impurity ions such as calcium and magnesium in the solution, and obtain the purified lithium-containing solution The composite additive in step S2 accounts for 5%-15% of the mass of the mixed ore of lepidolite and spodumene; In step S3, the roasting is carried out in a segmented heating mode, first preheating at 300 - 400℃ for 30-60 minutes to make the additive react with the ore, and then heating to 700 - 850℃ for 1-2 hours; In this process, the lithium in lepidolite is converted into easy-to-dissolve lithium salt under the action of the additive, at the same time the crystal structure of spodumene is changed, and lithium is more easily dissolved out, the two ores promote each other, and the overall dissolution efficiency of lithium is improved.

[0023] The use of composite additives and segmented heating roasting system reduces the roasting temperature and reduces energy consumption. Compared with the traditional spodumene sulfuric acid method for extracting lithium, the energy consumption is reduced by 30% - 40%.

[0024] In this embodiment, the specific implementation includes: Example 1: Ore pretreatment: After crushing lepidolite and spodumene respectively, mix them in a mass ratio of 1:1, and take 1000g in total. Fine grinding by ball mill to a particle size of less than 75μm; Additive mixing: Add a composite additive composed of 50g calcium fluoride, 30g sodium sulfate and 20g borax to the finely ground mixed ore, and stir evenly; Coordination roasting: the material is sent into a rotary kiln, preheated at 350℃ for 45 minutes, then heated to 750℃ for 1.5 hours; Leaching and solid-liquid separation: after the roasted product is cooled, it is added into a 10% mass fraction sulfuric acid solution, the liquid-solid ratio is 4:1, leaching is carried out at 70℃ for 1.5 hours, and filtration is performed to obtain a lithium-containing leaching solution and a leaching residue; Leaching solution purification: 5mL of 30% mass fraction hydrogen peroxide is added into the leaching solution, the pH value is adjusted to 4.5, and the precipitate is removed by filtration; trace impurities are removed by passing through an ion exchange resin column; Preparation of lithium carbonate: sodium carbonate solution is added into the purified lithium-containing solution, the pH value is controlled at 9, and battery-grade lithium carbonate is obtained after precipitation, filtration, washing and drying. Example 2:

[0025] Ore pretreatment: 1000g of lepidolite and spodumene are mixed in a mass ratio of 1:2 and finely ground to below 75μm; Additive mixing: 40g of calcium fluoride, 35g of sodium sulfate and 25g of borax are added as a composite additive; Coordination roasting: preheated at 320℃ for 60 minutes, then roasted at 800℃ for 1 hour; Leaching and solid-liquid separation: leaching with an 8% mass fraction sulfuric acid solution, liquid-solid ratio of 5:1, leaching at 65℃ for 2 hours; Leaching solution purification: 4mL of hydrogen peroxide is added, the pH value is adjusted to 4.2, and impurities are removed by ion exchange; Preparation of lithium carbonate: lithium is precipitated by adding ammonium carbonate solution, the pH value is 8.5, and battery-grade lithium carbonate is obtained after precipitation, filtration, washing and drying.

[0026] The application also provides a device for producing Li2CO3 based on coordination roasting of lepidolite and spodumene.

[0027] Please refer to Figure 2 and Figure 3 A device for producing Li2CO3 based on coordination roasting of lepidolite and spodumene, which is used in the method for producing Li2CO3 based on coordination roasting of lepidolite and spodumene, comprising: a support 1; An leaching cylinder 2 is detachably installed on the top of the cylinder cover 22, a discharge pipe 23 is arranged at the bottom of the leaching cylinder 2, a blocking assembly 6 is arranged on the discharge pipe 23, and a filter 7 is arranged in the discharge pipe 23 below the blocking assembly 6; A discharging cylinder 5 is installed on the cylinder cover 22, and a through hole is formed in the center of the cylinder cover 22 corresponding to the discharge port of the discharging cylinder 5; The stirring and discharging assembly 4 comprises a motor 41, a stirring shaft 42, a blade 43 and a screw feeder 44, the motor 41 is suspended above the discharging cylinder 5, one end of the stirring shaft 42 is connected with the output shaft of the motor 41, the other end sequentially penetrates the discharging cylinder 5 and the cylinder cover 22 and extends to the inside of the leaching cylinder 2, the blade 43 is installed on the stirring shaft 42 and located in the inside of the leaching cylinder 2, the screw feeder 44 is installed on the stirring shaft 42, and the top end of the screw feeder 44 is located in the discharging port of the discharging cylinder 5.

[0028] The device is mainly used for the steps S4, leaching and solid-liquid separation; In the process of adding the solid product into the sulfuric acid solution, the solid product needs to be slowly and uniformly added into the sulfuric acid solution to avoid local reaction from being too intense (such as generating a large amount of heat, bubbles, and even splashing of the solution, etc.). At present, for the production of lithium carbonate in the laboratory scale, the method of adding the solid product into the sulfuric acid solution during the leaching and solid-liquid separation usually includes manual feeding by using tools or using a small manual or screw propelling feeder, etc. The feeding operation needs to be assisted by a feeding device, and the manual feeding operation is troublesome. In this embodiment, the sulfuric acid solution is first added into the leaching cylinder 2, and then the solid product after roasting is added into the discharging cylinder 5, and at the same time, the stirring and discharging assembly 4 is working, the motor 41 drives the stirring shaft 42 to rotate the blade 43, slowly stirs the sulfuric acid solution, and at the same time, the screw feeder 44 rotates with the stirring shaft 42, the solid material in the inside of the discharging cylinder 5 enters the screw feeder 44 through the discharging port, the solid material flows into the sulfuric acid solution along the screw feeder 44, and after entering the sulfuric acid solution, the rotation of the blade 43 can uniformly mix the solid material with the sulfuric acid solution. Therefore, by arranging the discharging cylinder 5 and the screw feeder 44 on the stirring shaft 42, the solid material can be automatically and slowly added into the sulfuric acid solution, and the feeding operation is simple.

[0029] When the solid product is completely added into the sulfuric acid solution, the blade 43 continues to stir to ensure that the solid product and the sulfuric acid solution can fully react, and then the lithium-containing leaching solution is discharged through the discharge pipe 23, and the filter 7 filters the leaching residue.

[0030] For example, Figure 2 and Figure 3 The bottom end of the discharging cylinder 5 is conical, so that the material can automatically slide to the discharging port by gravity and enter the screw feeder 44.

[0031] The stirring shaft 42, the blade 43, the screw conveying part 44, and the inner wall of the leaching cylinder 2 are made of corrosion-resistant materials or are subjected to corrosion-resistant treatment, such as stainless steel, hastelloy, polytetrafluoroethylene, or a layer of acid-resistant material, such as PTFE, PVDF, or FRP.

[0032] Please refer to Figure 1 As an optional mode of the embodiment, the equipment for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene further comprises a lifting device 3, the lifting device 3 comprises a lifting cylinder 31 and a mounting frame 32, the lifting cylinder 31 is installed on the support 1 and is located above the motor 41, and the mounting frame 32 is installed on the output end of the lifting cylinder 31, and the motor 41 is installed on the mounting frame 32.

[0033] By arranging the lifting device 3, the height of the stirring and discharging assembly 4 can be adjusted, the blade 43 can be moved upwards to approach or move out of the leaching cylinder 2 when not in use, and the stirring and discharging assembly 4 can be conveniently cleaned and maintained; and during the working process, the depth of the blade 43 in the sulfuric acid solution can be adjusted, so that stirring and mixing are performed at different positions, and the mixing effect is improved.

[0034] In the embodiment, the lifting cylinder 31 can be an electric push, a pneumatic cylinder, or a hydraulic cylinder, and four corners of the top of the mounting frame 32 are provided with sliding rods, the top ends of the sliding rods penetrate through the top of the support 1, and sliding connection is formed, so that the lifting movement of the motor 41 is more stable.

[0035] As another optional mode of the embodiment, when the lifting device 3 is not arranged, a support can be additionally arranged to support the motor 41, and the motor 41 is suspended above the discharging cylinder 5.

[0036] Please refer to Figure 1 As an optional mode of the embodiment, the leaching cylinder 2 further comprises a liquid outlet pipe 21, and the liquid outlet pipe 21 is installed on the side of the leaching cylinder 2 and is away from one end of the cylinder cover 22.

[0037] When the leaching liquid is discharged, the upper part of the leaching liquid in the leaching cylinder 2 can be quickly discharged through the liquid outlet pipe 21 first, and finally the remaining part of the leaching liquid and the leaching residue are discharged from the leaching cylinder 2 by opening the discharging pipe 23, the leaching liquid is discharged through the filter screen, and the leaching residue is located on the filter screen. By arranging the liquid outlet pipe 21, the discharge speed of the leaching liquid is accelerated.

[0038] The height of the liquid outlet pipe is arranged to be higher than the precipitation height of the leaching residue above the blocking assembly 6, the liquid outlet pipe 21 is connected to a liquid conveying pipeline (not shown in the figure) through a valve, one end of the pipeline away from the liquid outlet pipe 21 is connected to a container for containing the leaching liquid, and a filter screen is preferably arranged in the liquid outlet pipe 21 to avoid a small amount of leaching residue from being discharged.

[0039] Please see Figure 4 and Figure 5 In this embodiment, the sealing assembly 6 includes a mounting box 61, a push cylinder 62, a connecting arm 63, and an L-shaped sealing plate 64. The mounting box 61 is connected to the discharge pipe 23. The L-shaped sealing plate 64 is slidably mounted on the mounting box 61. The push cylinder 62 is mounted on the mounting box 61. The connecting arm 63 connects the output end of the push cylinder 62 to the L-shaped sealing plate 64.

[0040] In this embodiment, the L-shaped sealing plate 64 is slidably connected to the mounting box 61.

[0041] When separating the filter cake and leachate, the pusher cylinder 62 pushes the L-shaped sealing plate 64 via the connecting arm 63, causing the L-shaped sealing plate 64 to move into the mounting box 61 and separate from the outlet of the leachate cylinder 2. At this time, the filter cake containing the leachate enters the discharge pipe 23. Figure 6 In (a), the filter residue is filtered by filter element 7, and the leachate is discharged into the leachate collection container through the leachate discharge; The push cylinder 62 is preferably installed on one side of the mounting box 61. The connecting arm 63 is L-shaped, with one end connected to the push cylinder 62 and the other end passing through the mounting box 61 and connected to the L-shaped sealing plate 64; and a mechanical seal is provided at the point where it passes through the mounting box 61.

[0042] The push cylinder 62 can be a pneumatic cylinder, a hydraulic cylinder, or an electric push rod.

[0043] In other embodiments, the push cylinder 62 in the sealing assembly 6 can also be replaced by a motor and lead screw structure. The motor is mounted on the mounting box 61, and the lead screw passes through the mounting box 61 and is connected to the output shaft of the motor. A nut is installed on the L-shaped sealing plate 64, and the nut is threadedly connected to the lead screw. At the same time, a through hole is opened on the L-shaped sealing plate 64 corresponding to the nut. When the nut drives the L-shaped sealing plate 64 to move along the lead screw, the L-shaped sealing plate 64 is sleeved on the lead screw through the through hole.

[0044] Please refer to it again. Figure 4 and Figure 5 In a preferred embodiment, the sealing component 6 further includes a pressure frame 65 and a pusher 66. The pressure frame 65 is slidably connected to the L-shaped sealing plate 64, and the pusher 66 connects the pressure frame 65 and the L-shaped sealing plate 64. The pusher 66 is used to drive the pressure frame 65 to move in the vertical direction.

[0045] By setting the pressure frame to 65, such as Figure 6 After the filter residue enters the discharge pipe 23, and there is clearly no leachate above the filter residue, the push cylinder 62 drives the L-shaped sealing plate 64 through the connecting arm 63 to seal the bottom of the leaching cylinder 2 again. Figure 6When the filter cake needs to be extruded to accelerate the discharge of the leaching liquid, the pushing member 66 pushes down the pressing frame 65, and the pressing frame 65 can extrude the filter cake, so that the un-discharged leaching liquid contained in the filter cake is quickly discharged, and the discharge of the leaching liquid is accelerated.

[0046] The side wall of the L-shaped sealing plate 64 is provided with a sliding groove, and the pressing frame 65 is provided with a sliding block corresponding to the side, and the sliding block is slid into the sliding groove to form a sliding connection; of course, the sliding block can also be arranged on the side wall of the L-shaped sealing plate 64, and the sliding groove is arranged on the pressing frame 65 correspondingly.

[0047] Please refer to Figure 4 As an optional mode of the embodiment, the pushing member 66 comprises a threaded sleeve 661, a threaded shaft 662 and a square shaft 663, the top end of the threaded sleeve 661 penetrates and is rotatably installed at the top of the L-shaped sealing plate 64, the square shaft 663 is installed at the top end of the threaded sleeve 661, the threaded shaft 662 is fixedly connected to the pressing frame 65, the threaded shaft 662 is threadedly connected to the threaded sleeve 661, and the top of the pressing frame 65 is sleeved on the threaded sleeve 661. The bottom end of the stirring shaft 42 is provided with a square groove 421.

[0048] In the embodiment, the top of the threaded sleeve 661 is provided with a sealing portion.

[0049] When the pressing frame 65 needs to be pushed down to extrude the filter cake and accelerate the discharge of the leaching liquid, the lifting device 3 pushes down the motor 41, the motor 41 drives the stirring shaft 42 to move downward, and the square groove 421 is sleeved on the square shaft 663, as shown in Figure 6 (a) to Figure 6 (b) in FIG. 6, and then the motor 41 drives the stirring shaft 42 to rotate clockwise, the stirring shaft 42 drives the threaded sleeve 661 to rotate through the cooperation of the square groove 421 and the square shaft 663, and since the pressing frame 65 is slidably arranged on the L-shaped sealing plate 64, the pressing frame 65 cannot rotate axially, that is, the threaded shaft 662 cannot rotate axially relative to the threaded sleeve 661, at this time, the threaded shaft 662 drives the pressing frame 65 to move downward to extrude the filter cake and accelerate the discharge of the leaching liquid. The subsequent motor 41 drives the stirring shaft 42 to rotate counterclockwise to drive the pressing frame 65 to move upward to the original position.

[0050] As another optional mode of the embodiment, the threaded sleeve 661 is fixed to the L-shaped sealing plate 64, and the top of the threaded sleeve 661 is provided with an opening, the threaded shaft 662 is rotatably connected to the pressing frame 65 at the bottom end, the top end of the threaded shaft 662 is threadedly connected to the threaded sleeve 661, and the square shaft 663 is installed at the top of the threaded shaft 662. When the square groove 421 is sleeved on the square shaft 663, the stirring shaft 42 drives the threaded shaft 662 to rotate through the square shaft 663, the threaded shaft 662 acts on the threaded sleeve 661, the pressing frame 65 is pushed down to extrude the filter cake, and in this process, the lifting device 3 drives the motor 41 to move downward, so that the square groove 421 and the square shaft 663 are assembled.

[0051] Preferably, the L-shaped sealing plate 64 is provided with a sealing block 642, which is embedded in the top of the side wall of the discharge pipe 23 and is in sliding connection with the mounting box 61. The sealing block 642 is aligned with the moving direction of the square shaft 663 along the L-shaped sealing plate 64. The top of the inner wall of the mounting box 61 is provided with a sliding groove, and the side wall of the discharge pipe 23 is provided with an embedded groove aligned with the sliding groove. By providing the sealing block 642, when the L-shaped sealing plate 64 is opened, the L-shaped sealing plate 64 can be completely collected into the mounting box 61 and is staggered with the bottom discharge end of the leaching cylinder 2. In this process, the square shaft 663 is slid into the mounting box 61 through the embedded groove and the sliding groove. When the L-shaped sealing plate 64 seals the bottom discharge end of the leaching cylinder 2, the sealing block 642 is embedded in the embedded groove to achieve sealing, so that the solution cannot enter the mounting box 61. A sealing sleeve is provided on the surface corresponding to the sealing block 642 to ensure sealing. Of course, the L-shaped sealing plate 64 can also be opened until the square shaft 663 abuts against the top of the side wall of the discharge pipe 23, at which time the part of the L-shaped sealing plate 64 that is not collected into the mounting box 61 is provided as an inclined surface, facilitating the entry of the filter residue into the discharge pipe 23.

[0052] Please refer to Figure 4 and Figure 5 as a preferred mode of the present embodiment, the equipment for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene further comprises a pushing structure 8, which comprises a pushing plate 81 and an assembly plate 82. The pushing plate 81 is arranged in close contact with the side wall of the discharge pipe 23 and is located between the pressing frame 65 and the filter element 7. The assembly plate 82 is connected to the top end of the pressing frame 65. The end of the pressing frame 65 and located above the assembly plate 82 is provided with a sleeve plate 651. The discharge pipe 23 and located below the mounting box 61 is provided with a slag discharge door 231.

[0053] In the present embodiment, the discharge pipe 23 is a square pipe, and the L-shaped sealing plate 64, the pressing frame 65, and the pushing plate 81 are correspondingly provided. The sleeve plate 651 is provided with an assembly cavity adapted to the assembly plate 82.

[0054] When the pressing frame 65 is pushed downward to press the filter residue and accelerate the discharge of the leaching solution, the sleeve plate 651 moves downward and is sleeved on the assembly plate 82. When the filter residue needs to be discharged subsequently, the slag discharge door 231 is disassembled, as shown in Figure 7In (b) in the above, the lifting device 3 lifts the motor 41 to separate the stirring shaft 42 from the square shaft 663, and then the cylinder 62 drives the L-shaped sealing plate 64 through the connecting arm 63 to move towards the slag door 231, the L-shaped sealing plate 64 is driven to move by the pushing piece 66, the pressing frame 65 is driven to move by the sleeve plate 651 and the assembly plate 82, and the pushing plate 81 is driven to move by the sleeve plate 651 and the assembly plate 82, and the pushing plate 81 pushes the filter residue to discharge the discharge pipe 23 to the preset collection container (not shown in the figure). After the discharge is completed, the pushing cylinder 62 pushes the L-shaped sealing plate 64 to seal the top of the discharge pipe 23 again, and then the stirring shaft 42 is assembled with the square shaft 663 again, so that the top of the pressing frame 65 is in close contact with the L-shaped sealing plate 64, and the sleeve plate 651 is separated from the assembly plate 82.

[0055] Therefore, during the process of pressing the filter residue in the pressing frame 65 to speed up the discharge speed of the leaching liquid, the sealing assembly 6 can be switched to the state of pushing the material, which is convenient for discharging the filter residue.

[0056] Among them, the sleeve plate 651 is installed on the top of one end of the pressing frame 65, so that when the pressing frame 65 moves downward, the sleeve plate 651 can move downward by a distance along the assembly plate 82, and can adapt to filter residues of different heights in the leaching liquid pipe 21 within a certain range. The volume of the discharge pipe 23 is set according to the volume of the leaching cylinder 2 and the amount of filter residue generated by the reaction.

[0057] Among them, as shown in Figure 4 , the height of the L-shaped sealing plate 64 is the same as the height of the inner cavity of the mounting box 61, the height of the pressing frame 65 is preferably half of the height of the mounting box 61, and the maximum height of the pressing frame 65 is flush with the bottom of the inner cavity of the mounting box 61. The side of the pressing frame 65 away from the slag door 231 is spaced apart from the inner wall of the discharge pipe 23, and the spacing is the same as the thickness of the pushing plate 81. The thickness value of the assembly plate 82 is less than the thickness value of the pushing plate 81.

[0058] In this embodiment, the filter 7 includes a filter plate and a soft filter screen, the filter plate provides support, the filter plate is provided with filter holes, and the soft filter screen provides filtering effect. Both the filter plate and the soft filter screen are treated with sulfuric acid or are made of sulfuric acid resistant material.

[0059] Please refer to Figure 3 , a plurality of plug shafts are arranged around the side of the cylinder cover 22, and the side of the leaching cylinder 2 is provided with positioning ears, the plug shafts are inserted into the positioning ears, and the detachable assembly of the cylinder cover 22 and the leaching cylinder 2 is realized. The plug shafts can be provided with threads, and the threads are matched with nuts to further fix.

[0060] The driving block 422 is arranged on the stirring shaft 42 and below the cylinder cover 22, and when the lifting device 3 drives the stirring and discharging assembly 4 to move upward, the driving block 422 can automatically drive the cylinder cover 22 to lift and separate from the leaching cylinder 2; The blanking cylinder 5 is preferably provided with a sealing cover (not shown in the figure), which is used to seal the blanking cylinder 5 after feeding, and the sealing cover is sleeved on the stirring shaft 42, and the sealing cover opening and the stirring shaft 42 are preferably mechanically sealed.

[0061] The leaching cylinder 2 is provided with a liquid inlet pipe for adding sulfuric acid solution into the leaching cylinder 2, and the sulfuric acid solution can also be added after opening the cylinder cover 22.

[0062] The leaching cylinder 2 is provided with a heating jacket (not shown in the figure) for adjusting the temperature of the leaching cylinder 2, and a thermometer, a barometer and other devices are also provided to detect the temperature, pressure and other conditions of the leaching cylinder 2 during operation.

[0063] Please refer to Figure 8 and Figure 9 As a preferred mode of the embodiment, the device for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene further comprises a pressing structure 9, which comprises a threaded pipe 91, an extrusion sleeve 92, an extrusion part 94 and four L-shaped rods 93. The four L-shaped rods 93 are arranged around the stirring shaft 42 in the blanking cylinder 5, and one end is connected with the blanking cylinder 5, and the other end is arranged in parallel, a plurality of L-shaped rods 93 are connected with a mounting ring, the top end of the threaded pipe 91 is rotatably connected with the mounting ring, the threaded pipe 91 is sleeved on the stirring shaft 42 and is connected with the stirring shaft 42 through a sliding key, the extrusion sleeve 92 is threadedly connected on the threaded pipe 91, the threaded pipe 91 is provided with reciprocating threads, the extrusion part 94 is installed at the bottom of the extrusion sleeve 92, and the extrusion sleeve 92 leaves a blanking gap with the inner wall of the blanking cylinder 5; the stirring shaft 42 is provided with a key block 423, and a corresponding sliding groove is formed in the threaded pipe 91, and the key block 423 is slid into the sliding groove to form a sliding key connection; wherein the extrusion part 94 is a pressing ring.

[0064] When the stirring shaft 42 rotates, the threaded pipe 91 is driven to rotate, and since the threaded pipe 91 is provided with reciprocating threads, the extrusion sleeve 92 moves up and down along the threaded pipe 91, and when the extrusion sleeve 92 moves downward, the extrusion part 94 at the bottom of the extrusion sleeve 92 extrudes the solid product, so that the solid product does not form lumps or particles that are too large to block the discharge port of the blanking cylinder 5, and does not contact with the sulfuric acid solution sufficiently, thereby affecting the reaction speed.

[0065] When the lifting device 3 lowers or lifts the stirring shaft 42 to separate the key block 423 from the threaded pipe 91, the rotation of the stirring shaft 42 will not drive the threaded pipe 91 to rotate.

[0066] The working principle of the method and device for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene provided by the present application is as follows: Then the calcined solid product is added into the discharging cylinder 5, while the discharging assembly 4 is working under stirring, the motor 41 drives the stirring shaft 42 to rotate with the blade 43, slowly stirring the sulfuric acid solution, while the screw conveying part 44 rotates with the stirring shaft 42, the solid material in the discharging cylinder 5 enters the screw conveying part 44 through the discharge port, the solid material flows into the sulfuric acid solution along the screw conveying part 44, after entering the sulfuric acid solution, the rotation of the blade 43 can uniformly mix the material with the sulfuric acid solution; thus, by arranging the discharging cylinder 5 with the screw conveying part 44 located on the stirring shaft 42, the slow and uniform addition of the solid material to the sulfuric acid solution can be automatically realized, and the feeding operation is simple.

[0067] When the filter residue and the leaching solution are separated, the push cylinder 62 pushes the L-shaped sealing plate 64 through the connecting arm 63, so that the L-shaped sealing plate 64 moves into the mounting box 61 and is separated from the liquid outlet of the leaching cylinder 2, at this time the filter residue containing the leaching solution enters the discharge pipe 23, as shown in (a) of FIG. 8, the filter residue is filtered by the filter part 7, and the leaching solution is discharged to the collection container of the leaching solution; Figure 6 After the filter residue enters the discharge pipe 23, and there is no leaching solution above the filter residue, the push cylinder 62 drives the L-shaped sealing plate 64 to block the bottom end of the leaching cylinder 2 again through the connecting arm 63, then the lifting device 3 pushes down the motor 41, the motor 41 drives the stirring shaft 42 to move downward, so that the square groove 421 is sleeved on the square shaft 663, as shown in (a) to (b) of FIG. 9, then the motor 41 drives the stirring shaft 42 to rotate clockwise, the stirring shaft 42 drives the threaded sleeve 661 to rotate through the square groove 421 cooperating with the square shaft 663, since the pressing frame 65 is slidably arranged on the L-shaped sealing plate 64, it cannot rotate axially, that is, the threaded shaft 662 cannot rotate axially relative to the threaded sleeve 661, at this time the threaded shaft 662 drives the pressing frame 65 to move downward, extruding the filter residue and accelerating the discharge of the leaching solution; Figure 6 Figure 6 and in the process of pushing down the pressing frame 65 to press the filter residue and accelerate the discharge of the leaching solution, the cover plate 651 moves downward and is sleeved on the assembly plate 82, when the filter residue needs to be discharged subsequently, the discharge door 231 is disassembled, as shown in (b) of FIG. 10, the lifting device 3 lifts up the motor 41 to separate the stirring shaft 42 from the square shaft 663, then the push cylinder 62 drives the L-shaped sealing plate 64 to move towards the discharge door 231 through the connecting arm 63, the L-shaped sealing plate 64 drives the pressing frame 65 to move through the pushing part 66, the pressing frame 65 drives the push plate 81 to move through the cover plate 651 and the assembly plate 82, the push plate 81 pushes the filter residue to discharge from the discharge pipe 23 to the pre-set collection container (not shown in the figure); Figure 7 thereby, in the process of pressing the filter residue with the pressing frame 65 to accelerate the discharge speed of the leaching solution, the blocking assembly 6 can be switched to the state of pushing the material, which is convenient for discharging the filter residue.

[0068] ​​​​The above merely illustrates the embodiments of the present application, and is not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process conversion, or direct or indirect application in other related technical fields, which is made according to the content of the present application, shall be included in the patent protection scope of the present application.

Claims

1. A process for the production of Li2CO3 based on the coordinated roasting of lepidolite and spodumene, characterized in that, Comprise: S1, ore pretreatment: the particle size of less than 5mm lepidolite and spodumene are mixed uniformly according to the mass ratio 1: (1-3), and the mixed ore is finely ground, so that the particle size is less than 75μm; S2, additive mixing: adding composite additive to the finely ground mixed ore and mixing uniformly, the composite additive is composed of fluoride, sulfate and flux; S3, coordinated roasting: the mixed material is sent into the rotary kiln for roasting; S4, leaching and solid-liquid separation: after the solid product is cooled, it is added into the sulfuric acid solution with mass fraction of 5%-25% for leaching, and solid-liquid separation is realized by filtration, obtaining the lithium-containing leaching solution and leaching residue, wherein the liquid-solid ratio is (2-6):1; S5, leaching solution purification: adding a predetermined amount of hydrogen peroxide to the lithium-containing leaching solution, then adjusting the solution pH value to 4-5, filtering the precipitate, and finally removing the residual impurity ions in the solution by ion exchange resin method, obtaining the purified lithium-containing solution; S6, lithium carbonate preparation: adding sodium carbonate or ammonium carbonate solution to the purified lithium-containing solution, controlling the reaction pH value at 8-11, generating lithium carbonate precipitate, then filtering, washing and drying to obtain lithium carbonate.

2. The process for the production of Li2CO3 based on the coordinated roasting of lepidolite and spodumene according to claim 1, characterized in that, The composite additive in step S2 accounts for 5%-15% of the mass of the mixed lepidolite and spodumene ore.

3. The method and apparatus for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene according to claim 1, characterized in that, In step S3, the roasting is carried out in a segmented heating mode, first preheating at 300-400℃ for 30-60 minutes to make the additive react with the ore initially, and then heating to 700-850℃ for 1-2 hours.

4. An apparatus for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene, characterized by, The device for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene according to any one of claims 1-3, comprising: an immersion cylinder, a cylinder cover being detachably installed at the top of the immersion cylinder, a discharge pipe being arranged at the bottom of the immersion cylinder, a plugging assembly being arranged on the discharge pipe, a filter being arranged in the discharge pipe below the plugging assembly; a feeding cylinder, the feeding cylinder being installed on the cylinder cover, a through hole being formed in the center of the cylinder cover corresponding to the discharge port of the feeding cylinder; a stirring and feeding assembly, the stirring and feeding assembly comprising a motor, a stirring shaft, a blade and a spiral feeding element, the motor being suspended above the feeding cylinder, one end of the stirring shaft being connected with the output shaft of the motor, the other end of the stirring shaft penetrating the feeding cylinder and the cylinder cover in sequence and extending into the interior of the immersion cylinder, the blade being installed on the stirring shaft and located in the interior of the immersion cylinder, the spiral feeding element being installed on the stirring shaft, and the top end of the spiral feeding element being located in the discharge port of the feeding cylinder.

5. The apparatus for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene according to claim 4, characterized in that, The device for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene further comprises a lifting device, the lifting device comprising a lifting cylinder and a mounting bracket, the lifting cylinder being installed on the support and located above the motor, the mounting bracket being installed on the output end of the lifting cylinder, and the motor being installed on the mounting bracket.

6. The apparatus for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene according to claim 4, characterized in that, The immersion cylinder further comprises a liquid outlet pipe, the liquid outlet pipe being installed on the side of the immersion cylinder away from the cylinder cover.

7. The apparatus for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene according to claim 4, characterized in that, The plugging assembly comprises a mounting box, a pushing cylinder, a connecting arm and an L-shaped sealing plate, the mounting box is communicated and mounted on the discharge pipe, the L-shaped sealing plate is slidingly mounted on the mounting box, the pushing cylinder is mounted on the mounting box, and the connecting arm connects the output end of the pushing cylinder and the L-shaped sealing plate.

8. The apparatus for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene according to claim 7, characterized in that, The plugging assembly further comprises a pressing frame and a pushing piece, the pressing frame is slidingly connected in the L-shaped sealing plate, the pushing piece connects the pressing frame and the L-shaped sealing plate, and the pushing piece is used for driving the pressing frame to move in the vertical direction.

9. The apparatus for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene according to claim 8, characterized in that, The pushing piece comprises a threaded sleeve, a threaded shaft and a square shaft, the top end of the threaded sleeve penetrates and is rotatably mounted on the top of the L-shaped sealing plate, the square shaft is mounted on the top end of the threaded sleeve, the threaded shaft is fixedly connected on the pressing frame, the threaded shaft is threadedly connected with the threaded sleeve, and the top of the pressing frame is sleeved on the threaded sleeve. The bottom end of the stirring shaft is provided with a square groove.

10. The apparatus for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene according to claim 9, characterized in that, The equipment for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene further comprises a pushing structure, the pushing structure comprises a pushing plate and an assembly plate, the pushing plate is arranged on the side wall of the discharge pipe and located between the pressing frame and the filtering piece, the assembly plate is connected to the top end of the pressing frame, a sleeve plate is mounted on the end of the pressing frame and above the assembly plate, and a slag outlet is detachably mounted on the discharge pipe and below the mounting box.

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