A method and apparatus for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene

Abstract

The application 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 following steps: S1, ore pretreatment: mixing lepidolite and spodumene with a particle size less than 5 mm at a mass ratio of 1: (1-3) uniformly, and finely grinding the mixed ore to make the particle size less than 75 mu m; S2, additive mixing: adding a composite additive to the finely ground mixed ore and mixing the composite additive with the ore uniformly, wherein the composite additive is composed of fluoride, sulfate and fluxing agent; S3, coordinated roasting: feeding the mixed material into a rotary kiln for roasting. The method for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene provided by the application realizes complementary advantages by coordinated roasting of lepidolite and spodumene, utilizes the differences in structure and chemical properties of the two, improves the overall extraction rate of lithium, and compared with the single lithium extraction process, the lithium recovery rate can be increased by 10%-20%, and the amount of waste residue generated 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. Lithium carbonate is a key lithium source for the preparation of positive electrode materials and electrolytes. The raw materials for the preparation of lithium carbonate generally include lepidolite and spodumene.

[0003] In the prior art, the structure of lepidolite is complex, and the presence of alkali metal elements such as potassium and sodium leads to a long lithium extraction process, high cost, and low 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 the two types of ore, and there is a lack of efficient methods for synergistically utilizing the characteristics of the two 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 the two 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;

[0007] S2, additive mixing: adding a composite additive to the finely ground mixed ore and uniformly mixing the composite additive with the ore, the composite additive being composed of a fluoride, a sulfate, and a fluxing agent;

[0008] S3, coordinated roasting: feeding the mixed material into a rotary kiln for roasting;

[0009] S4, leaching and solid-liquid separation: after cooling, the roasted solid product is added to 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;

[0010] S5, leaching solution purification: a predetermined amount of hydrogen peroxide is added to the lithium-containing leaching solution, then the pH value of the solution is adjusted to 4-5, the precipitate is filtered, and finally ion exchange resin method is used to remove the residual impurity ions in the solution to obtain the purified lithium-containing solution;

[0011] S6, lithium carbonate preparation: sodium carbonate or ammonium carbonate solution is added to the purified lithium-containing solution, the reaction pH value is controlled at 8-11, lithium carbonate precipitate is generated, then after filtration, washing and drying, lithium carbonate is obtained.

[0012] Preferably, the composite additive accounts for 5%-15% of the mass of the lepidolite and spodumene mixed ore in step S2.

[0013] Preferably, the step S3 adopts a segmented temperature rising roasting method, 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.

[0014] 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.

[0015] 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 plugging assembly, and the discharge pipe is provided with a filter element below the plugging assembly.

[0016] 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.

[0017] The stirring and discharging assembly comprises a motor, a stirring shaft, a blade and a spiral conveying element, 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 element is installed on the stirring shaft, and the top end of the spiral conveying element is located in the discharge port of the discharge cylinder.

[0018] 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.

[0019] Preferably, the leaching cylinder further comprises a liquid outlet pipe, which is installed on the side of the leaching cylinder and away from one end of the cylinder cover.

[0020] Preferably, the plugging assembly comprises a mounting box, a push cylinder, a connecting arm and an L-shaped sealing plate, the mounting box is communicatively installed on the discharge pipe, the L-shaped sealing plate is slidingly installed on the mounting box, the push cylinder is installed on the mounting box, and the connecting arm connects the output end of the push cylinder and the L-shaped sealing plate.

[0021] Preferably, the plugging assembly further comprises a pressing frame and a pusher, the pressing frame is slidingly connected in the L-shaped sealing plate, the pusher connects the pressing frame and the L-shaped sealing plate, and the pusher is used to drive the pressing frame to move in the vertical direction.

[0022] Preferably, the pusher comprises a threaded sleeve, a threaded shaft and a square shaft, the top end of the threaded sleeve penetrates and is rotatably installed on the top of the L-shaped sealing plate, the square shaft is installed 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.

[0023] The bottom end of the stirring shaft is provided with a square groove.

[0024] Preferably, the equipment for producing Li2CO3 based on 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 in close contact with the side wall of the discharge pipe and is located between the pressing frame and the filtering element, the assembly plate is connected to the top end of the pressing frame, a sleeve plate is installed on the end of the pressing frame and above the assembly plate, and a slag outlet is detachably installed on the discharge pipe and below the mounting box.

[0025] Compared with the related art, the method for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene has the following beneficial effects:

[0026] The method for producing Li2CO3 based on coordinated roasting of lepidolite and spodumene has the following beneficial effects: BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1A flowchart illustrating the steps of the method for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene provided by the present invention.

[0028] 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.

[0029] 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.

[0030] Figure 4 for Figure 3 The enlarged schematic diagram of part A shown below;

[0031] Figure 5 This is a schematic diagram of the internal structure of the discharge pipe provided by the present invention;

[0032] Figure 6 This is a schematic diagram showing the state of filter residue entering the discharge pipe provided by the present invention, wherein... Figure 6 (a) is a schematic diagram showing the state of the filter residue entering the discharge pipe when the L-shaped sealing plate is open. Figure 6 (b) is a schematic diagram of an L-shaped sealing plate sealing the top of the discharge pipe and the stirring shaft being sleeved on a square shaft;

[0033] Figure 7 This is a schematic diagram of the state of the filter cake tray discharge pipe provided by the present invention, wherein, Figure 7 (a) is a schematic diagram of the state of the filter cake being pressed down by the pressure frame. Figure 7 (b) is a schematic diagram showing the state of the pusher plate pushing the filter residue out of the discharge pipe;

[0034] Figure 8 This is a schematic diagram of the pressing structure provided by the present invention;

[0035] Figure 9 This is a bottom view of the pressing structure provided by the present invention.

[0036] Numbering on the map:

[0037] 1. Bracket;

[0038] 2. Leaching cylinder; 21. Liquid outlet pipe; 22. Cylinder cover; 23. Material outlet pipe; 231. Slag outlet door;

[0039] 3. Lifting device; 31. Lifting cylinder; 32. Mounting frame;

[0040] 4. Mixing and feeding assembly; 41. Motor; 42. Mixing shaft; 43. Blades; 44. Screw conveyor;

[0041] 421. Square groove; 422. Drive block; 423. Key block;

[0042] 5. Feeding cylinder;

[0043] 6. Sealing assembly; 61. Mounting box; 62. Push cylinder; 63. Connecting arm; 64. L-shaped sealing plate; 65. Pressure frame; 66. Pushing component;

[0044] 661. Threaded sleeve; 662. Threaded shaft; 663. Square shaft; 651. Sleeve plate; 642. Sealing block;

[0045] 7. Filter components;

[0046] 8. Pushing structure; 81. Push plate; 82. Assembly plate;

[0047] 9. Pressing structure; 91. Threaded tube; 92. Extrusion sleeve; 93. L-shaped rod; 94. Extrusion section. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0049] This invention provides a method for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene.

[0050] Please refer to the following: Figures 1 to 5 In one embodiment of the present invention, the method for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene includes: S1, ore pretreatment: lepidolite with a particle size of less than 5 mm is mixed with spodumene at a mass ratio of 1:(1-3), and the mixed ore is finely ground to make the particle size less than 75 μm.

[0051] S2. Additive mixing: Add composite additives to finely ground mixed ore and mix them evenly with the ore. The composite additives are composed of fluorides (such as calcium fluoride), sulfates (such as sodium sulfate) and fluxes (such as borax).

[0052] S3. Coordinated roasting: The mixed materials are fed into a rotary kiln for roasting;

[0053] S4. Leaching and solid-liquid separation: After cooling, the calcined solid product is added to a sulfuric acid solution with a mass fraction of 5% - 25% for leaching, and solid-liquid separation is achieved by filtration to obtain lithium-containing leaching solution and leaching residue, wherein the liquid-solid ratio is (2-6):1.

[0054] S5. Leachate purification: Add a preset amount of hydrogen peroxide to the lithium-containing leachate, then adjust the pH of the solution to 4-5, filter the precipitate, and finally use the ion exchange resin method to remove the residual impurity ions in the solution to obtain the purified lithium-containing solution.

[0055] S6. Preparation of lithium carbonate: Add sodium carbonate or ammonium carbonate solution to the purified lithium-containing solution, control the reaction pH value at 8-11, and generate lithium carbonate precipitate. Then, after filtration, washing and drying, lithium carbonate is obtained.

[0056] By coordinating the calcination of lepidolite and spodumene, and leveraging their structural and chemical differences, complementary advantages are achieved, improving the overall lithium extraction rate. Compared to individual lithium extraction processes, the lithium recovery rate can be increased by 10%-20%. Furthermore, the amount of waste generated is reduced, while the leaching and purification processes are optimized, reducing the amount of chemical reagents used, mitigating environmental pollution, improving resource utilization, reducing energy consumption and reagent costs, and lowering the overall lithium extraction cost by 20%-30%.

[0057] Specifically, during coordinated roasting, the potassium salts (such as K2O) and fluorides (such as HF) produced by the decomposition of lepidolite at lower temperatures can act as "natural fluxes" to penetrate into the dense structure of spodumene, disrupting the stability of its silicon-oxygen chains and lowering the temperature of spodumene crystal transformation (α→β) (e.g., from 1000℃ to 800-900℃), thus reducing 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 interlayer fracture of lepidolite, improving the permeability of the roasted product, and facilitating the contact of subsequent leaching agents with lithium ions.

[0058] K in lepidolite + Replaces external sodium salts, reducing auxiliary agent costs; F - Immobilizing Al in spodumene 3+ This reduces aluminum impurities in the leachate and improves lithium purity. Simultaneously, the Si in spodumene can react with excess Al produced during the calcination of lepidolite to form stable aluminosilicates, avoiding Al... 3+ During leaching, the lithium particles are coated with precipitate to ensure complete dissolution of lithium;

[0059] Furthermore, after coordinated roasting, spodumene transforms into a readily acid-leached β-phase, while lepidolite decomposes into easily soluble lithium salts and residues containing potassium (K) and phosphorus (F). During leaching, the strong acid required for spodumene can simultaneously satisfy the leaching of lithium from lepidolite, eliminating the need for staged acidity adjustments; and the calcium (Ca) in spodumene (with the addition of limestone as an aid) can react with the phosphorus (F) in lepidolite. - By combining the formation of CaF2 precipitate, the problem of fluoride contamination is addressed simultaneously, simplifying the process. Furthermore, the leaching of lithium from both minerals in the same system avoids lithium loss due to differences in leaching conditions during separate treatments, thus improving the overall recovery rate.

[0060] In step S5, an appropriate amount of hydrogen peroxide is added to the lithium-containing leachate to oxidize ferrous ions to ferric ions. Then, the pH of the solution is adjusted to 4-5, causing impurities such as ferric and aluminum ions to precipitate as hydroxides, which are then removed by filtration. Next, an ion exchange resin method is used to remove residual trace impurity ions such as calcium and magnesium ions from the solution, resulting in a purified lithium-containing solution.

[0061] In step S2, the composite additive accounts for 5%-15% of the mass of the mixed ore of lepidolite and spodumene;

[0062] In step S3, a segmented heating and roasting method is adopted. First, the temperature is preheated at 300-400℃ for 30-60 minutes to allow the additives to react initially with the ore, and then the temperature is raised to 700-850℃ for roasting for 1-2 hours.

[0063] During this process, lithium in lepidolite is converted into easily soluble lithium salts under the action of additives. At the same time, the crystal structure of spodumene is changed, making lithium easier to dissolve. The two minerals promote each other and improve the overall lithium dissolution efficiency.

[0064] By using composite additives and a segmented heating and roasting process, the roasting temperature was reduced, thus reducing energy consumption. Compared with the traditional spodumene sulfuric acid process for lithium extraction, energy consumption was reduced by 30% to 40%.

[0065] In this embodiment, the specific implementation methods include: Embodiment 1:

[0066] Ore pretreatment: Lepidolite and spodumene are crushed separately and then mixed in a 1:1 mass ratio, with a total weight of 1000g. The mixture is then finely ground in a ball mill to a particle size of less than 75μm.

[0067] Additive mixing: Add a composite additive consisting of 50g calcium fluoride, 30g sodium sulfate and 20g borax to the finely ground mixed ore and stir evenly.

[0068] Coordinated roasting: The material is fed into a rotary kiln, preheated at 350℃ for 45 minutes, and then roasted at 750℃ for 1.5 hours.

[0069] Leaching and solid-liquid separation: After the calcined product is cooled, it is added to a 10% sulfuric acid solution with a liquid-to-solid ratio of 4:1. The product is leached at 70°C for 1.5 hours, and then filtered to obtain lithium-containing leachate and leaching residue.

[0070] Leachate purification: Add 5 mL of 30% hydrogen peroxide to the leachate, adjust the pH to 4.5, filter to remove the precipitate, and then pass it through an ion exchange resin column to remove trace impurities;

[0071] Lithium carbonate preparation: Sodium carbonate solution is added to the purified lithium-containing solution, the pH value is controlled at 9, and after precipitation, filtration, washing and drying, battery-grade lithium carbonate is obtained. Example 2:

[0072] Ore pretreatment: 1000g of lepidolite and spodumene are mixed at a mass ratio of 1:2 and ground to below 75μm;

[0073] Additive mixture: Add a compound additive consisting of 40g calcium fluoride, 35g sodium sulfate and 25g borax;

[0074] Harmonious roasting: Preheat at 320℃ for 60 minutes, then roast at 800℃ for 1 hour;

[0075] Leaching and solid-liquid separation: Leaching with 8% sulfuric acid solution (by mass fraction), liquid-to-solid ratio 5:1, leaching at 65℃ for 2 hours;

[0076] Leachate purification: Add 4 mL of hydrogen peroxide, adjust the pH to 4.2, and remove impurities by ion exchange;

[0077] Lithium carbonate preparation: Lithium is precipitated by adding ammonium carbonate solution at pH 8.5. After precipitation, filtration, washing, and drying, battery-grade lithium carbonate is obtained.

[0078] The present invention also provides an apparatus for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene.

[0079] Please see Figure 2 and Figure 3 An apparatus for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene, and a method for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene, comprising: a support 1;

[0080] The leaching cylinder 2 has a detachable cap 22 installed on its top and a discharge pipe 23 provided at its bottom. A sealing component 6 is provided on the discharge pipe 23 and a filter element 7 is provided inside the discharge pipe 23 and below the sealing component 6.

[0081] The feeding cylinder 5 is installed on the cylinder cover 22, and the center of the cylinder cover 22 is provided with a through hole corresponding to the discharge port of the feeding cylinder 5;

[0082] The mixing and feeding assembly 4 includes a motor 41, a mixing shaft 42, blades 43, and a spiral conveyor 44. The motor 41 is suspended above the feeding cylinder 5. One end of the mixing shaft 42 is connected to the output shaft of the motor 41, and the other end passes through the feeding cylinder 5 and the cylinder cover 22 in sequence and extends into the interior of the leaching cylinder 2. The blades 43 are installed on the mixing shaft 42 and are located inside the leaching cylinder 2. The spiral conveyor 44 is installed on the mixing shaft 42, and the top end of the spiral conveyor 44 is located inside the discharge port of the feeding cylinder 5.

[0083] This equipment is mainly used for step S4, leaching and solid-liquid separation;

[0084] When adding the calcined solid product to a sulfuric acid solution, the solid product needs to be added slowly and evenly to avoid violent local reactions (such as generating a large amount of heat, bubbles, or even splashing of the solution) caused by adding the product too quickly. Currently, for laboratory-scale lithium carbonate production, the methods for adding the solid product to the sulfuric acid solution during leaching and solid-liquid separation typically include manual feeding using tools or using small manual or screw-propelled feeders. These methods require feeding equipment, and manual feeding is particularly cumbersome.

[0085] In this embodiment, sulfuric acid solution is first added to leaching cylinder 2, and then the calcined solid product is added to feeding cylinder 5. At the same time, stirring and feeding assembly 4 is working. Motor 41 drives stirring shaft 42 to rotate blades 43, slowly stirring the sulfuric acid solution. Meanwhile, spiral conveyor 44 follows stirring shaft 42. Solid material inside feeding cylinder 5 enters spiral conveyor 44 through discharge port. Solid material flows into sulfuric acid solution along spiral conveyor 44. After entering sulfuric acid solution, blades 43 rotate to ensure that material is evenly mixed with sulfuric acid solution. Thus, by setting feeding cylinder 5 in conjunction with spiral conveyor 44 located on stirring shaft 42, the slow and even addition of solid material to sulfuric acid solution can be automatically achieved, and the feeding operation is simple.

[0086] After the solid product is completely added to the sulfuric acid solution, blade 43 continues to stir to ensure that the solid product and sulfuric acid solution can react fully; subsequently, the lithium-containing leaching solution is discharged through discharge pipe 23, and filter element 7 filters the leaching residue.

[0087] like Figure 2 and Figure 3 The bottom of the feed cylinder 5 is conical, which makes it easy for the material to slide automatically to the discharge port by gravity and enter the screw conveyor 44.

[0088] In this invention, the parts that come into contact with the sulfuric acid solution, such as the stirring shaft 42, blades 43, spiral conveyor 44, and the inner wall of the leaching cylinder 2, are all made of corrosion-resistant materials or undergo corrosion-resistant treatment, such as stainless steel, Hastelloy, polytetrafluoroethylene, or lined with an acid-resistant material, such as PTFE, PVDF, or glass fiber reinforced plastic (FRP).

[0089] Please see Figure 1 As an optional embodiment, the equipment for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene further includes a lifting device 3. The lifting device 3 includes a lifting cylinder 31 and a mounting frame 32. The lifting cylinder 31 is installed on the bracket 1 and located above the motor 41. The mounting frame 32 is installed at the output end of the lifting cylinder 31, and the motor 41 is installed on the mounting frame 32.

[0090] By setting up the lifting device 3, the height of the stirring and feeding component 4 can be adjusted. When not in use, the blades 43 can be moved up to approach or move out of the leaching cylinder 2, which facilitates cleaning and maintenance of the stirring and feeding component 4. During operation, the depth of the blades 43 in the sulfuric acid solution can be adjusted, so that stirring and mixing can be carried out at different positions, thereby improving the mixing effect.

[0091] In this embodiment, the lifting cylinder 31 can be electrically driven, pneumatic, or hydraulic. Each of the four corners of the top of the mounting bracket 32 ​​is provided with a sliding rod, the top of which passes through the top of the bracket 1 to form a sliding connection, thereby making the lifting movement of the motor 41 more stable.

[0092] As another optional approach in this embodiment, when the lifting device 3 is not provided, a separate bracket can be provided to support the motor 41, so that the motor 41 is suspended above the feed cylinder 5.

[0093] Please see Figure 1 As an optional embodiment, the leaching cylinder 2 further includes a liquid outlet pipe 21, which is installed on the side of the leaching cylinder 2 and at one end away from the cylinder cover 22.

[0094] When discharging the leachate, the upper portion of the leachate in the leaching cylinder 2 can be quickly discharged through the outlet pipe 21 first. Finally, the remaining leachate and leaching residue can be discharged from the leaching cylinder 2 by opening the discharge pipe 23. The leachate is discharged through the filter screen, and the leaching residue is located on the filter screen. The discharge pipe 21 is set to speed up the discharge of the leachate.

[0095] The height of the outlet pipe is set higher than the sedimentation height of the leaching residue above the sealing component 6. The outlet pipe 21 is connected to the delivery pipeline (not shown in the figure) through a valve. The end of the pipeline away from the outlet pipe 21 is connected to the container for holding the leaching liquid. Preferably, a filter screen is installed in the outlet pipe 21 to prevent a small amount of leaching residue from being discharged.

[0096] 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.

[0097] In this embodiment, the L-shaped sealing plate 64 is slidably connected to the mounting box 61.

[0098] 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;

[0099] 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.

[0100] The push cylinder 62 can be a pneumatic cylinder, a hydraulic cylinder, or an electric push rod.

[0101] 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.

[0102] 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.

[0103] 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 6In (b), the pusher 66 then pushes down the pressing frame 65, which can squeeze the filter to quickly discharge the undischarged leachate contained in the filter residue and accelerate the discharge of leachate.

[0104] The L-shaped sealing plate 64 has a sliding groove on its side wall, and the pressure frame 65 has a corresponding slider on its side. The slider slides into the sliding groove to form a sliding connection. Alternatively, the L-shaped sealing plate 64 can have a slider on its side wall, and the pressure frame 65 can have a corresponding sliding groove.

[0105] Please see Figure 4 As an optional embodiment, the pusher 66 includes a threaded sleeve 661, a threaded shaft 662, and a square shaft 663. The top end of the threaded sleeve 661 passes through and is rotatably mounted on the top of the L-shaped sealing plate 64. The square shaft 663 is mounted on the top end of the threaded sleeve 661. The threaded shaft 662 is fixedly connected to the pressure frame 65. The threaded shaft 662 is threadedly connected to the threaded sleeve 661. The top of the pressure frame 65 is sleeved on the threaded sleeve 661.

[0106] A square groove 421 is provided at the bottom end of the stirring shaft 42.

[0107] In this embodiment, the top of the threaded sleeve 661 is sealed.

[0108] When it is necessary to push down the pressure frame 65 to squeeze the filter residue and accelerate the discharge of leachate, the lifting device 3 pushes down the motor 41. The motor 41 drives the stirring shaft 42 to move down, so that the square groove 421 is fitted onto the square shaft 663. Figure 6 (a) to Figure 6 In (b), 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 and the square shaft 663. Since the pressure frame 65 is slidably set on the L-shaped sealing plate 64, it will not rotate axially. That is, the threaded shaft 662 will not rotate axially relative to the threaded sleeve 661. At this time, the threaded shaft 662 drives the pressure frame 65 to move down, squeeze the filter residue, and accelerate the discharge of leachate.

[0109] The subsequent motor 41 drives the stirring shaft 42 to rotate counterclockwise, thereby moving the pressure frame 65 to its original position.

[0110] As another optional embodiment, the threaded sleeve 661 is fixed on the L-shaped sealing plate 64, with an open top. The bottom end of the threaded shaft 662 is rotatably connected to the pressure frame 65, and the top end of the threaded shaft 662 is threadedly connected to the threaded sleeve 661. The square shaft 663 is installed on the top of the threaded shaft 662. When the square groove 421 is fitted onto the square shaft 663, the stirring shaft 42 drives the threaded shaft 662 to rotate through the square shaft 663. The threaded shaft 662 interacts with the threaded sleeve 661, pushing down the pressure frame 65 to squeeze the filter residue. During this process, the lifting device 3 drives the motor 41 to move down, keeping the square groove 421 and the square shaft 663 assembled.

[0111] Preferably, a sealing block 642 is installed on the L-shaped sealing plate 64. The sealing block 642 is embedded in the top of the side wall of the discharge pipe 23 and is slidably connected to the mounting box 61. The sealing block 642 and the square shaft 663 are aligned in the direction of movement of the L-shaped sealing plate 64. A corresponding groove is opened on the top of the inner wall of the mounting box 61, and an embedding groove is opened on the side wall of the discharge pipe 23. The embedding groove is aligned with the groove.

[0112] By setting the sealing block 642, when the L-shaped sealing plate 64 is opened, the L-shaped sealing plate 64 can be completely retracted into the mounting box 61, offset from the bottom discharge end of the leaching cylinder 2. During this process, the square shaft 663 slides into the mounting box 61 through the embedded groove and the sliding groove. When the L-shaped sealing plate 64 blocks the bottom discharge end of the leaching cylinder 2, the sealing block 642 is embedded in the embedded groove to achieve the blockage, preventing the solution from entering the mounting box 61. A sealing sleeve is fitted on the surface of the sealing block 642 to ensure the sealing performance.

[0113] Alternatively, the L-shaped sealing plate 64 can be opened partially, i.e., stopped when the square shaft 663 abuts against the top of the side wall of the discharge pipe 23. At this time, the part of the top of the L-shaped sealing plate 64 that is not retracted into the mounting box 61 is set as an inclined surface, which facilitates the filter residue to enter the discharge pipe 23.

[0114] Please refer to it again. Figure 4 and Figure 5 As a preferred embodiment, the equipment for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene further includes a pushing structure 8. The pushing structure 8 includes a pushing plate 81 and an assembly plate 82. The pushing plate 81 is disposed against the side wall of the discharge pipe 23 and is located between the pressure frame 65 and the filter element 7. The assembly plate 82 is connected to the top of the pressure frame 65. A sleeve plate 651 is installed at the end of the pressure frame 65 and above the assembly plate 82. A slag discharge door 231 is detachably installed on the discharge pipe 23 and below the mounting box 61.

[0115] In this embodiment, the discharge pipe 23 is a square pipe, and the L-shaped sealing plate 64, pressure frame 65, push plate 81, etc. are all correspondingly provided. The sleeve plate 651 has an assembly cavity adapted to the assembly plate 82.

[0116] As the pressing frame 65 pushes down the filter residue to accelerate the discharge of leachate, the sleeve 651 moves down and is fitted onto the assembly plate 82. When the filter residue needs to be discharged later, the discharge door 231 is disassembled. Figure 7In step (b), the lifting device 3 raises the motor 41 to separate the stirring shaft 42 from the square shaft 663. Then, the pusher cylinder 62 drives the L-shaped sealing plate 64 towards the slag discharge gate 231 via the connecting arm 63. The L-shaped sealing plate 64 drives the pressure frame 65 to move along with it via the pusher 66. The pressure frame 65 drives the pusher plate 81 to move along with it via the sleeve plate 651 and the assembly plate 82. The pusher plate 81 pushes the filter residue out of the discharge pipe 23 into the preset collection container (not shown). After the discharge is completed, the pusher cylinder 62 pushes the L-shaped sealing plate 64 to seal the top of the discharge pipe 23 again. Subsequently, the stirring shaft 42 is reassembled with the square shaft 663, so that the top of the pressure frame 65 fits against the L-shaped sealing plate 64, and the sleeve plate 651 separates from the assembly plate 82.

[0117] Thus, during the process of pressing the filter residue under the pressure frame 65 to accelerate the discharge of leachate, the sealing component 6 can be switched to the pushing state, which facilitates the discharge of the filter residue.

[0118] The sleeve plate 651 is installed on the top of one end of the pressure frame 65, so that when the pressure frame 65 moves down, the sleeve plate 651 can move down a certain distance along the assembly plate 82, which can accommodate filter residue at different heights in the discharge pipe 21 within a certain range. The volume of the discharge pipe 23 is set according to the amount of filter residue that can be generated by the conventional reaction of the leaching cylinder 2.

[0119] Among them, such as Figure 4 The height of the L-shaped sealing plate 64 is the same as the inner cavity height of the mounting box 61. The height of the pressure frame 65 is preferably half the height of the mounting box 61. The maximum height of the pressure frame 65 when it descends is such that its bottom is flush with the bottom of the inner cavity of the mounting box 61. The side of the pressure frame 65 away from the slag discharge door 231 has a gap with the inner wall of the discharge pipe 23. The gap is the same as the thickness of the push plate 81. The thickness of the assembly plate 82 is less than the thickness of the push plate 81.

[0120] In this embodiment, the filter element 7 comprises a filter plate and a flexible filter screen. The filter plate provides support and has filter holes, while the flexible filter screen provides filtration. Both the filter plate and the flexible filter screen are treated with sulfuric acid resistant materials or are made of sulfuric acid resistant materials.

[0121] Please see Figure 3 The cap 22 has multiple insert shafts arranged around its sides, and the corresponding leaching cylinder 2 has positioning ears on its sides. The insert shafts are inserted into the positioning ears to achieve detachable assembly of the cap 22 and the leaching cylinder 2. Alternatively, the insert shafts can be threaded to be further secured with nuts.

[0122] A drive block 422 is provided on the stirring shaft 42 and below the cylinder cover 22. When the lifting device 3 drives the stirring and feeding assembly 4 to move upward, the drive block 422 can automatically drive the cylinder cover 22 to be lifted and separated from the leaching cylinder 2.

[0123] The feeding cylinder 5 is preferably equipped with a sealing cover (not shown in the figure) to seal the feeding cylinder 5 after feeding. The central opening of the sealing cover is fitted onto the stirring shaft 42, and a mechanical seal is preferably formed between the opening of the sealing cover and the stirring shaft 42.

[0124] The leaching cylinder 2 is equipped with a liquid inlet pipe for adding sulfuric acid solution into the leaching cylinder 2. Alternatively, the sulfuric acid solution can be added after opening the cylinder cover 22.

[0125] The leaching cylinder 2 is equipped with a heating jacket (not shown) to regulate the temperature of the leaching cylinder 2. It is also equipped with thermometers, barometers and other devices to detect the temperature, pressure and other conditions of the leaching cylinder 2 during operation.

[0126] Please see Figure 8 and Figure 9 As a preferred embodiment, the equipment for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene further includes a pressing structure 9, which includes a threaded tube 91, an extrusion sleeve 92, an extrusion section 94, and four L-shaped rods 93.

[0127] Four L-shaped rods 93 are arranged around the stirring shaft 42 inside the feeding cylinder 5, with one end connected to the feeding cylinder 5 and the other end parallel to it. Mounting rings connect the multiple L-shaped rods 93. The top end of the threaded tube 91 is rotatably connected to the mounting rings, and the threaded tube 91 is sleeved on the stirring shaft 42 and keyed to the stirring shaft 42. An extrusion sleeve 92 is threadedly connected to the threaded tube 91, and the threaded tube 91 has reciprocating threads. An extrusion part 94 is installed at the bottom of the extrusion sleeve 92, and a feeding gap is left between the extrusion sleeve 92 and the inner wall of the feeding cylinder 5. A key block 423 is provided on the stirring shaft 42, and a corresponding groove is opened on the threaded tube 91. The key block 423 slides into the groove to form a keyed connection. The extrusion part 94 is a pressure ring.

[0128] When the stirring shaft 42 rotates, it drives the threaded tube 91 to rotate. Since the threaded tube 91 is provided with reciprocating threads, the extrusion sleeve 92 moves up and down along the threaded tube 91. When the extrusion sleeve 92 moves down, it drives the extrusion part 94 at its bottom to extrude the solid product, so as to avoid the solid product from clumping or having excessively large particles, which would block the outlet of the feed cylinder 5 and cause insufficient contact with the sulfuric acid solution, thus affecting the reaction rate.

[0129] When the lifting device 3 lowers or raises the stirring shaft 42 to separate the key block 423 from the threaded tube 91, the rotation of the stirring shaft 42 will not drive the threaded tube 91 to rotate.

[0130] The working principle of the method and equipment for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene provided by this invention is as follows:

[0131] Then, the calcined solid product is added into the feeding cylinder 5. At the same time, the stirring and feeding component 4 works, and the motor 41 drives the stirring shaft 42 to rotate the blades 43, slowly stirring the sulfuric acid solution. Meanwhile, the screw conveyor 44 rotates with the stirring shaft 42. The solid material inside the feeding cylinder 5 enters the screw conveyor 44 through the discharge port. The solid material flows into the sulfuric acid solution along the screw conveyor 44. After entering the sulfuric acid solution, the blades 43 rotate so that the material can be evenly mixed with the sulfuric acid solution. Thus, by setting the feeding cylinder 5 in conjunction with the screw conveyor 44 located on the stirring shaft 42, the solid material can be automatically and slowly added to the sulfuric acid solution, and the feeding operation is simple.

[0132] 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;

[0133] 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. Then, the lifting device 3 pushes down the motor 41, and the motor 41 drives the stirring shaft 42 to move down, so that the square groove 421 is fitted onto the square shaft 663. Figure 6 (a) to Figure 6 In (b), 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 and the square shaft 663. Since the pressure frame 65 is slidably set on the L-shaped sealing plate 64, it will not rotate axially. That is, the threaded shaft 662 will not rotate axially relative to the threaded sleeve 661. At this time, the threaded shaft 662 drives the pressure frame 65 to move down, squeeze the filter residue, and accelerate the discharge of leachate.

[0134] Furthermore, during the process of the lower push frame 65 pressing down the filter residue to accelerate the discharge of leachate, the sleeve plate 651 moves down and is fitted onto the assembly plate 82. When the filter residue needs to be discharged later, the slag discharge door 231 is disassembled. Figure 7 In (b), the lifting device 3 raises 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 towards the slag discharge door 231 through the connecting arm 63. The L-shaped sealing plate 64 drives the pressure frame 65 to move along through the pusher 66. The pressure frame 65 drives the push plate 81 to move along through the sleeve plate 651 and the assembly plate 82. The push plate 81 pushes the filter residue out of the discharge pipe 23 into the preset collection container (not shown).

[0135] Thus, during the process of pressing the filter residue under the pressure frame 65 to accelerate the discharge of leachate, the sealing component 6 can be switched to the pushing state, which facilitates the discharge of the filter residue.

[0136] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene, characterized in that, include: S1. Ore pretreatment: Lithium mica with a particle size of less than 5 mm is mixed with spodumene at a mass ratio of 1:(1-3), and the mixed ore is finely ground to make the particle size less than 75 μm. S2. Additive mixing: Add composite additives to finely ground mixed ore and mix them evenly with the ore. The composite additives consist of fluorides, sulfates and fluxes. S3. Coordinated roasting: The mixed materials are fed into a rotary kiln for roasting; S4. Leaching and solid-liquid separation: After cooling, the calcined solid product is added to a sulfuric acid solution with a mass fraction of 5% - 25% for leaching, and solid-liquid separation is achieved by filtration to obtain lithium-containing leaching solution and leaching residue, wherein the liquid-solid ratio is (2-6):

1. S5. Leachate purification: Add a preset amount of hydrogen peroxide to the lithium-containing leachate, then adjust the pH of the solution to 4-5, filter the precipitate, and finally use the ion exchange resin method to remove the residual impurity ions in the solution to obtain the purified lithium-containing solution. S6. Preparation of lithium carbonate: Add sodium carbonate or ammonium carbonate solution to the purified lithium-containing solution, control the reaction pH value at 8-11, and generate lithium carbonate precipitate. Then, after filtration, washing and drying, lithium carbonate is obtained.

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

3. The method and equipment for producing Li₂CO₃ based on the coordinated roasting of lepidolite and spodumene according to claim 1, characterized in that, In step S3, a segmented heating and roasting method is adopted. First, the temperature is preheated at 300-400℃ for 30-60 minutes to allow the additives to react initially with the ore, and then the temperature is raised to 700-850℃ for roasting for 1-2 hours.

4. An apparatus for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene, characterized in that, The method for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene as described in any one of claims 1-3 includes: a support; The leaching cylinder has a detachable cap installed on its top and a discharge pipe installed at its bottom. A sealing assembly is installed on the discharge pipe, and a filter element is installed inside the discharge pipe and below the sealing assembly. A feeding cylinder is installed on the cylinder cover, and a through hole is provided in the center of the cylinder cover corresponding to the discharge port of the feeding cylinder; The mixing and feeding assembly includes a motor, a mixing shaft, blades, and a spiral conveyor. The motor is suspended above the feeding cylinder. One end of the mixing shaft is connected to the output shaft of the motor, and the other end passes through the feeding cylinder and the cylinder cover in sequence and extends into the interior of the leaching cylinder. The blades are installed on the mixing shaft and located inside the leaching cylinder. The spiral conveyor is installed on the mixing shaft, and the top end of the spiral conveyor is located inside the discharge port of the feeding cylinder.

5. The equipment for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene according to claim 4, characterized in that, The equipment for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene also includes a lifting device, which includes a lifting cylinder and a mounting frame. The lifting cylinder is mounted on the bracket and located above the motor. The mounting frame is mounted on the output end of the lifting cylinder, and the motor is mounted on the mounting frame.

6. The equipment for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene according to claim 4, characterized in that, The leaching cylinder also includes a liquid outlet pipe, which is installed on the side of the leaching cylinder and at one end away from the cylinder cover.

7. The equipment for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene according to claim 4, characterized in that, The sealing assembly includes a mounting box, a push cylinder, a connecting arm, and an L-shaped sealing plate. The mounting box is connected to the discharge pipe, the L-shaped sealing plate is slidably mounted on the mounting box, the push cylinder is mounted on the mounting box, and the connecting arm connects the output end of the push cylinder to the L-shaped sealing plate.

8. The equipment for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene according to claim 7, characterized in that, The sealing assembly further includes a pressure frame and a pusher. The pressure frame is slidably connected within the L-shaped sealing plate, and the pusher connects the pressure frame and the L-shaped sealing plate. The pusher is used to drive the pressure frame to move vertically.

9. The equipment for producing Li2CO3 based on the coordinated roasting of lepidolite and spodumene according to claim 8, characterized in that, 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.

10. The equipment 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 also includes a pushing structure, which includes a pushing plate and an assembly plate. The pushing plate is fitted to 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.

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