A method for extracting lithium from lepidolite based on sodium sulfide

Abstract

This invention provides a method for extracting lithium from lepidolite using sodium sulfide, relating to the field of resource utilization technology. The method includes the following steps: Step S1, lepidolite is fed into a planetary ball mill for grinding and crushing; the crushed material is then screened to obtain screened material; Step S2, the screened material is uniformly mixed with anhydrous sodium sulfide at a weight ratio of 1:1 to 3; the mixture is then subjected to high-intensity grinding, and mechanical energy triggers a chemical reaction between the lepidolite and anhydrous sodium sulfide to obtain reactant material. When using a combination of mixed grinding and water leaching to extract lithium from lepidolite, sulfation and defluorination heat treatment are eliminated, effectively improving lithium extraction efficiency; and the lithium precipitation mother liquor is recycled back to the "sodium sulfide preparation" step, achieving resource recycling of sodium, which conforms to energy-saving and environmentally friendly development standards.

Description

Technical Field

[0001] This invention relates to the field of resource utilization technology, and in particular to a method for extracting lithium from lepidolite based on sodium sulfide. Background Technology

[0002] With the anticipated continued and substantial growth in demand for lithium batteries used in hybrid and pure electric vehicles, relying solely on natural brine will be insufficient to meet future needs. Therefore, recent research has focused on extracting lithium from minerals such as lepidolite, lepidolite, and zeolite. Among these minerals, the extraction process from lepidolite has received significant attention due to its widespread distribution, low iron content, and the presence of rare metals such as rubidium (Rb) and cesium (Cs), making it highly valuable for comprehensive utilization.

[0003] The process of extracting lithium from lepidolite mainly includes two stages: sulfation and water leaching. Sulfation can be carried out using either the sulfuric acid method or the lime method.

[0004] However, the sulfuric acid method for lithium extraction requires the use of high-concentration acid, which not only increases the cost of raw materials but also makes the subsequent purification process more complex and affects the extraction efficiency. The lime method requires the use of limestone and has high energy consumption, which is not conducive to energy conservation and environmental protection. In addition, in order to improve the lithium extraction rate from lepidolite through water leaching, steam heating must be introduced to remove fluoride, which also increases the complexity and cost of the process.

[0005] Therefore, it is necessary to provide a method for extracting lithium from lepidolite based on sodium sulfide to solve the above-mentioned technical problems. Summary of the Invention

[0006] This invention provides a method for extracting lithium from lepidolite based on sodium sulfide, which solves the problem in related technologies where how to reduce lithium extraction costs while ensuring lithium extraction efficiency requires further research.

[0007] To address the aforementioned technical problems, this invention provides a method for extracting lithium from lepidolite based on sodium sulfide, comprising the following steps:

[0008] Step S1: The lithium mica is fed into a planetary ball mill for grinding and crushing. The crushed material is then screened to obtain screened material.

[0009] Step S2: The screened material and anhydrous sodium sulfide are uniformly mixed in a weight ratio of 1:1 to 3; the mixture is then subjected to high-intensity grinding, and the chemical reaction between lepidolite and anhydrous sodium sulfide is initiated by mechanical energy to obtain the reactant material.

[0010] Step S3: Add the reactants to deionized water at a slurry density of 20 g / L, and perform leaching to dissolve the activated lithium into the aqueous solution; separate the leachate and filter residue using a filtration device.

[0011] Step S4: Add H2O2 solution to the leachate at a volume ratio of 1:30~50, stir for 30 minutes, and remove Fe. 2+ Oxidized to Fe 3+ Adjust the pH with ammonia, let stand for 1 hour, and allow the Fe... 3+ Hydrolysis produces a flocculent precipitate of Fe(OH)3, which is filtered to remove impurities and then settled.

[0012] Step S5: Add saturated Na2CO3 solution to the settling solution and adjust the pH to 7-8, so that Ca... 2+ Mg 2+ CaCO3 and MgCO3 precipitates are generated and removed; then CO2 is introduced to adjust the pH to 6-7, so that Al... 3+ Al(OH)3 precipitate is generated and removed; both precipitates need to be aged at 80℃ for 1 hour, and the purified solution is obtained after filtration and separation;

[0013] Step S6: First, pass the impurity removal solution into the resin column, and then elute the resin with 0.5 mol / L HCl to obtain a high-concentration lithium chloride solution.

[0014] Step S7: Heat the high-concentration lithium chloride solution to 90°C, add saturated Na2CO3 solution at a constant speed while stirring, react to generate Li2CO3 precipitate, keep warm and age for 2 hours; then use a material conveying device to transport and discharge the Li2CO3 precipitate.

[0015] Preferably, in step S1, minerals that pass through a 200-mesh standard sieve during screening are returned to the planetary ball mill for recycling and grinding if they do not reach 200 mesh or less.

[0016] Preferably, the method for preparing anhydrous sodium sulfide in step S2 is to perform a dehydration process on sodium sulfide nonahydrate to remove water of crystallization and obtain anhydrous sodium sulfide.

[0017] Preferably, the dehydration process involves calcination at 120°C for 6 hours.

[0018] Preferably, the reaction leaching conditions in step S3 are room temperature, magnetic stirring speed of 500~600 rpm, and leaching time of 30 minutes.

[0019] Preferably, in step S4, the pH is adjusted to 4.0 ± 0.3.

[0020] Preferably, the resin column in step S6 is a lithium-ion chelating resin column.

[0021] Preferably, in step S7, during the material conveying and discharging process, the precipitate is washed three times with deionized water at 60°C, and then dried in a vacuum drying oven at 110°C for 4 hours.

[0022] Preferably, the material conveying device includes:

[0023] Support components;

[0024] A conveying pipe is installed on the support assembly. A flushing nozzle is provided at the top of the conveying pipe, and an isolation filter screen is provided at the bottom of the conveying pipe. The flushing nozzle and the isolation filter screen are aligned vertically. A connection hole is provided on the conveying pipe.

[0025] A conveying assembly includes a first driving component, a connecting slide shaft, a spiral conveying sleeve, and a docking slide. The fixing part of the first driving component is fixedly disposed at one end of the conveying pipe. One end of the connecting slide shaft passes through the conveying pipe and is fixedly connected to the driving part of the first driving component. The spiral conveying sleeve is keyed on the connecting slide shaft. The docking slide is fixed on the spiral conveying sleeve and slidably disposed inside the conveying pipe. A limit groove is formed on the docking slide.

[0026] A feed pipe is provided at the top of the conveying pipe, and a feed impeller is rotatably installed inside the feed pipe. The output end of the feed pipe is connected to the inside of the conveying pipe.

[0027] A transmission component, which passes through the connecting hole and drives the connecting slide shaft and the feeding impeller;

[0028] The locking assembly includes a connecting frame, a second telescopic member, and a locking plug. The connecting frame is fixed on the conveying pipe, the fixing part of the second telescopic member is fixed on the connecting frame, the bottom of the locking plug is fixedly connected to the telescopic part of the second telescopic member, and the top of the locking plug penetrates the conveying pipe and is inserted into the limiting groove.

[0029] Preferably, the material conveying device further includes a liquid supply assembly, which includes a liquid storage box, a liquid supply pump, and a diversion box. The liquid storage box is fixed at the bottom of the conveying pipe and is aligned with the lower part of the isolation filter. The liquid supply pump is installed inside the liquid storage box, and its input end is connected to the inside of the liquid storage box. The diversion box is fixed on the liquid storage box, and its output end passes through the liquid storage box and is connected to one end of a first connecting pipe. The other end of the first connecting pipe is connected to the input end of the diversion box, and the output end of the diversion box is connected to the input end of the flushing nozzle through a second connecting pipe.

[0030] Compared with related technologies, the method for extracting lithium from lepidolite based on sodium sulfide provided by the present invention has the following beneficial effects:

[0031] When lithium is extracted from lepidolite using a combination of grinding and water immersion, sulfation and defluorination heat treatment are not required, which can effectively improve the extraction efficiency of lithium. Furthermore, the lithium precipitation mother liquor is recycled to the "sodium sulfide preparation" step, realizing the resource recycling of sodium, which is in line with the development standards of energy conservation and environmental protection. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0033] Figure 1 A system flow diagram of a method for extracting lithium from lepidolite based on sodium sulfide is provided for this invention;

[0034] Figure 2 A three-dimensional view of a first embodiment of the material transfer device provided by the present invention;

[0035] Figure 3 for Figure 2 A schematic diagram of the cross-sectional structure of section AA shown;

[0036] Figure 4 for Figure 3 A cross-sectional structural diagram of the locking plug connection portion is shown;

[0037] Figure 5 for Figure 3 A schematic diagram of the three-dimensional cross-sectional structure of the feed impeller section shown;

[0038] Figure 6 for Figure 1 A 3D view of the entire conveying pipe from another perspective;

[0039] Figure 7 for Figure 6 A plan view of the liquid supply assembly section shown in the top section;

[0040] Figure 8 for Figure 7 The diagram shown illustrates the structure of the liquid supply assembly adjusted to self-circulation mode.

[0041] Figure 9 A three-dimensional view of a second embodiment of the material conveying device provided by the present invention;

[0042] Figure 10 for Figure 9 An enlarged schematic diagram of part A shown;

[0043] Figure 11 for Figure 9 A schematic diagram of the cross-sectional structure of the distribution box section shown;

[0044] Figure 12 This is a schematic diagram of a second embodiment of the material conveying device provided by the present invention, wherein, Figure 12 (a) in the diagram is the state diagram during the downward movement of the locking plug-in. Figure 12 (b) in the diagram shows the state of the locking plug about to disengage from the limit slide. Figure 12 (c) in the diagram shows the state where the locking plug is completely withdrawn from the limit slide. Figure 12 (d) in the middle is Figure 12 The orientation diagram of the mating holes in state (a) is shown. Figure 12 (e) in the middle is Figure 12 The orientation diagram of the mating holes in state (b) is shown. Figure 12 (f) in the middle is Figure 12 Orientation diagram of the mating hole in state (c).

[0045] Explanation of icon numbers:

[0046] 1. Support component; 11. Base; 12. Support frame; 13. First telescopic component;

[0047] 2. Delivery pipe; 201. Connection hole; 21. Flushing nozzle; 22. Isolation filter screen;

[0048] 3. Conveying assembly; 31. First driving component; 32. Connecting slide shaft; 33. Screw conveyor sleeve; 34. Docking slide; 341. Limiting slide groove;

[0049] 4. Feed pipe; 41. Feed impeller;

[0050] 5. Transmission components;

[0051] 6. Liquid supply assembly; 61. Liquid storage box; 611. Liquid replacement pipe; 62. Liquid supply pump; 621. First connecting pipe; 63. Diverter box; 631. Second connecting pipe; 64. Rotating cover; 641. Connecting hole; 65. Second driving component; 66. Activated carbon filter column;

[0052] 7. Locking component; 71. Connecting bracket; 72. Second telescopic component; 73. Locking insert;

[0053] 651. Synchronous shaft; 652. Gear;

[0054] 731. Gear rack.

[0055] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0056] 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.

[0057] This invention provides a method for extracting lithium from lepidolite based on sodium sulfide.

[0058] Please see Figure 1 In this invention, a method for extracting lithium from lepidolite based on sodium sulfide includes the following steps:

[0059] Step S1: The lithium mica is fed into a planetary ball mill for grinding and crushing. The crushed material is then screened to obtain screened material.

[0060] Step S2: The screened material and anhydrous sodium sulfide are uniformly mixed in a weight ratio of 1:1 to 3; the mixture is then subjected to high-intensity grinding, and the chemical reaction between lepidolite and anhydrous sodium sulfide is initiated by mechanical energy to obtain the reactant material.

[0061] Step S3: Add the reactants to deionized water at a slurry density of 20 g / L, and perform leaching to dissolve the activated lithium into the aqueous solution; separate the leachate and filter residue using a filtration device.

[0062] Step S4: Add H2O2 solution to the leachate at a volume ratio of 1:30~50, stir for 30 minutes, and remove Fe. 2+ Oxidized to Fe 3+ Adjust the pH with ammonia (NH3·H2O), let stand for 1 hour, and allow the Fe... 3+ Hydrolysis produces a flocculent precipitate of Fe(OH)3, which is filtered to remove impurities and then settled.

[0063] Step S5: Add saturated Na2CO3 solution to the settling solution and adjust the pH to 7-8, so that Ca... 2+ Mg 2+ CaCO3 and MgCO3 precipitates are generated and removed; then CO2 is introduced to adjust the pH to 6-7, so that Al... 3+ Al(OH)3 precipitate is generated and removed; both precipitates need to be aged at 80℃ for 1 hour, and the purified solution is obtained after filtration and separation;

[0064] Step S6: First, pass the impurity removal solution into the resin column, and then elute the resin with 0.5 mol / L HCl to obtain a high-concentration lithium chloride solution.

[0065] Step S7: Heat the high-concentration lithium chloride solution to 90°C, add saturated Na2CO3 solution at a constant speed while stirring, react to generate Li2CO3 precipitate, keep warm and age for 2 hours; then use a material conveying device to transport and discharge the Li2CO3 precipitate.

[0066] In this embodiment, the mechanical energy can be the shearing / impact mode of ball milling or vibratory milling.

[0067] After obtaining the leachate in step S3, the lithium concentration in the leachate is directly measured. The filter residue is chemically digested, such as by boiling and dissolving it with strong acid, and then the residual lithium concentration is measured.

[0068] Specifically, in step S1, minerals that pass through a 200-mesh standard sieve but do not reach 200 mesh are returned to the planetary ball mill for recycling and grinding.

[0069] Specifically, the method for preparing anhydrous sodium sulfide in step S2 is to perform a dehydration process on sodium sulfide nonahydrate to remove water of crystallization and obtain anhydrous sodium sulfide.

[0070] Specifically, the dehydration process involves calcining at 120°C for 6 hours.

[0071] Specifically, the reaction leaching conditions in step S3 are room temperature, magnetic stirring speed of 500~600 rpm, and leaching time of 30 minutes.

[0072] Specifically, in step S4, the pH is adjusted to 4.0 ± 0.3.

[0073] Specifically, in step S6, the resin preferentially adsorbs Li. + , while Na + K + 、Rb + It will be discharged with the waste liquid later.

[0074] Specifically, the resin column in step S6 is a lithium-ion chelating resin column. It can be LSC-800, CH-90Na, HPL700, D401, etc.

[0075] Specifically, in step S7, during the material conveying and discharging process, the precipitate is washed three times with deionized water at 60°C, and then dried in a vacuum drying oven at 110°C for 4 hours.

[0076] Beneficial effects:

[0077] When lithium is extracted from lepidolite using a combination of grinding and water immersion, sulfation and defluorination heat treatment are not required, which can effectively improve the extraction efficiency of lithium. Furthermore, the lithium precipitation mother liquor is recycled to the "sodium sulfide preparation" step, realizing the resource recycling of sodium (reducing Na2S procurement costs by more than 30%), which is in line with the development standards of energy conservation and environmental protection.

[0078] Using low-grade lepidolite as a raw material for lithium production provides a new technological approach and is expected to further promote the development of the lithium extraction industry.

[0079] Comparative Example 1:

[0080] The raw lepidolite ore is crushed to ≤2mm using a jaw crusher, and then ground to 200 mesh using a ball mill. The undersize material is collected for later use.

[0081] Weigh out sodium sulfide nonahydrate (Na2S・9H2O) and dehydrate it in a vacuum drying oven at 120℃ for 6 hours to obtain anhydrous Na2S.

[0082] Weigh out 2.5g of Na2S + 2.5g of lepidolite (Group G1), 3.333g of Na2S + 1.667g of lepidolite (Group G2), and 3.75g of Na2S + 1.25g of lepidolite (Group G3) according to Na2S:lepidolite ratios of 1:1, 2:1, and 3:1 respectively.

[0083] Premix the materials separately for 3 minutes using an agate mortar and pestle to ensure that each batch of materials is evenly dispersed.

[0084] Each mixture was added separately to a ball mill jar and ground at 300 rpm for 6 hours to obtain three groups of ground materials (G1, G2, and G3).

[0085] Take 5.0g of ground material for each group and mix it with 50mL of deionized water. The water bath temperature is 80℃, the stirring speed is 300rpm, and the soaking time is 2 hours.

[0086] Filter while hot and collect the leachate (containing Li). + The lithium concentration in the three filtrates (including impurities) and filter residue was measured. The filter residue was chemically digested by boiling with strong acid to dissolve it, and then the residual lithium concentration was measured.

[0087] The lithium leaching rate was measured to be 82.4% for group G1, 90.06% for group G2, and 91.2% for group G3.

[0088] Take 50 mL of leachate from each group and add 1 mL of 30% H2O2 solution to the leachate, then stir for 30 minutes.

[0089] Adjust the pH to 4.0 with 25% NH3·H2O, let stand for 1 hour, and allow Fe to...3+ Hydrolysis produces Fe(OH)3 precipitate, and the Fe content of the filtrate is detected by filtration.

[0090] First, add a saturated Na2CO3 solution to adjust the pH to 8.5. CaCO3 and MgCO3 precipitates will be generated and removed. Then, keep the solution at 80℃ for 1 hour.

[0091] Then, CO2 is introduced to adjust the pH to 7.5, so that Al 3+ The Al(OH)3 precipitate was generated and removed, and the mixture was aged at 80℃ for 1 hour.

[0092] Two filtrations were performed to obtain three sets of purified solutions, and the Ca, Mg, and Al contents of the filtrates were measured.

[0093] The three groups of impurity removal solutions were respectively passed into LSC-800 ion exchange resin columns, with the flow rate controlled at 1 BV / h (1 column volume / hour), so that Li + It is preferentially adsorbed by the resin.

[0094] The high-concentration LiCl solution was collected by eluting with 0.5 mol / L HCl at a flow rate of 1 BV / h.

[0095] Heat the LiCl solution to 90°C, add a saturated Na2CO3 solution (10% excess) at a constant rate while stirring, and keep it warm for 2 hours.

[0096] After filtration, the precipitate was collected, washed three times with deionized water at 60℃, and dried under vacuum at 110℃ for 4 hours to obtain three groups of Li2CO3.

[0097] Comparative Example 2:

[0098] The experimental steps and conditions were exactly the same as those in Comparative Example 1. The only difference was that Na2S was not added when grinding the lepidolite. The final lithium leaching rate was 4.53%.

[0099] When lithium was extracted from lepidolite using a combination of grinding and water immersion, the experimental results showed clear patterns and significant effects. In the experimental setup, the mixing ratio (by weight) of sodium sulfide and lepidolite was controlled within the range of 1:1 to 3:1.

[0100] The comparison revealed that regardless of the adjustment of the ratio within this range, the lithium leaching rate of the mixed ground material with added sodium sulfide was significantly improved after water immersion; while the lithium extraction rate of pure lepidolite without added sodium sulfide was only 4.53% after grinding alone. The difference between the two was extremely obvious, which fully demonstrates the key role of sodium sulfide in the extraction process.

[0101] Meanwhile, the experiment also observed that the lithium leaching rate gradually increased with the extension of grinding time. When the weight ratio of sodium sulfide to lepidolite reached 3:1, the lithium leaching rate could reach as high as 92% after mixing, grinding, and then extraction by water leaching, achieving the ideal effect. Furthermore, the lithium precipitation mother liquor (containing NaCl) was recycled to the "sodium sulfide preparation (dehydration)" or "mixing step," realizing the resource recycling of sodium (reducing Na2S procurement costs by more than 30%), which is in line with the development standards of energy conservation and environmental protection.

[0102] Overall, this process, by introducing sodium sulfide and optimizing the mixing ratio and grinding time, achieves the goal of efficiently extracting lithium from lepidolite, providing a simple and efficient technical path for the resource utilization of lepidolite.

[0103] The present invention also provides a material conveying device for conveying and discharging materials in the method for extracting lithium from lepidolite based on sodium sulfide.

[0104] First embodiment:

[0105] Please refer to the following: Figures 2 to 5 In this invention, a material conveying device includes:

[0106] Support component 1;

[0107] The conveying pipe 2 is installed on the support assembly 1. A flushing nozzle 21 is provided at the top of the conveying pipe 2, and an isolation filter screen 22 is provided at the bottom of the conveying pipe 2. The flushing nozzle 21 and the isolation filter screen 22 are aligned vertically. A connection hole 201 is provided on the conveying pipe 2.

[0108] The conveying assembly 3 includes a first driving member 31, a connecting slide shaft 32, a spiral conveying sleeve 33, and a docking slide 34. The fixing part of the first driving member 31 is fixedly disposed at one end of the conveying pipe 2. One end of the connecting slide shaft 32 passes through the conveying pipe 2 and is fixedly connected to the driving part of the first driving member 31. The spiral conveying sleeve 33 is keyedly mounted on the connecting slide shaft 32. The docking slide 34 is fixedly disposed on the spiral conveying sleeve 33 and is slidably mounted inside the conveying pipe 2. A limiting groove 341 is formed on the docking slide 34.

[0109] Feed pipe 4 is disposed at the top of conveying pipe 2. A feeding impeller 41 is rotatably installed inside the feed pipe 4. The output end of the feed pipe 4 is connected to the inside of the conveying pipe 2.

[0110] Transmission component 5, which passes through the connection hole 201 and is connected to the connecting slide shaft 32 and the feeding impeller 41;

[0111] The locking component 7 includes a connecting frame 71, a second telescopic member 72, and a locking plug 73. The connecting frame 71 is fixed on the conveying pipe 2, the fixing part of the second telescopic member 72 is fixed on the connecting frame 71, the bottom of the locking plug 73 is fixedly connected to the telescopic part of the second telescopic member 72, and the top of the locking plug 73 penetrates the conveying pipe 2 and is inserted into the limiting slide groove 341.

[0112] In this embodiment, "sliding key connection" means that the spiral conveying sleeve 33 and the connecting sliding shaft 32 can be adjusted horizontally, and the connecting sliding shaft 32 can drive the spiral conveying sleeve 33 to rotate synchronously, providing support for quick replacement of the spiral conveying sleeve 33.

[0113] In this embodiment, at least three rinsing nozzles 21 are provided to meet the requirement of three water washings in the method for extracting lithium from lepidolite based on sodium sulfide.

[0114] In this embodiment, the spiral conveying sleeve 33 has two usage states:

[0115] In the locked state, the top of the locking plug 73 is fully inserted into the range of the limiting slide groove 341, and the docking slide 34 and the spiral conveying sleeve 33 cannot slide left or right relative to the connecting slide shaft 32, ensuring the stability of the spiral conveying sleeve 33 when it is installed on the connecting slide shaft 32 for rotational adjustment, so as to facilitate the stable transmission of materials by the spiral conveying sleeve 33.

[0116] In the unlocked state, the top of the locking plug 73 is completely withdrawn from the range of the limiting slide groove 341, and the docking slide 34 and the spiral conveying sleeve 33 can slide left and right relative to the connecting slide shaft 32. The spiral conveying sleeve 33 can be removed from the connecting slide shaft 32, which facilitates the maintenance and management of the spiral conveying sleeve 33.

[0117] In this embodiment, after the locking plug 73 is inserted into the limiting slide groove 341, it can lock the docking slide 34 so that the docking slide 34 and the spiral conveying sleeve 33 are stably installed on the connecting slide shaft 32; however, it will not affect the rotation of the docking slide 34 and the spiral conveying sleeve 33 inside the conveying pipe 2.

[0118] During material transfer, the material is first fed into the inside of the feed pipe 4. During the process of the first drive component 31 controlling the spiral conveying sleeve 33 to rotate and convey, the connecting slide shaft 32 drives the feeding impeller 41 to rotate synchronously through the transmission component 5. The feeding impeller 41 feeds the material in batches downward into the rotational conveying range of the spiral conveying sleeve 33, avoiding the phenomenon of accumulation caused by direct feeding.

[0119] During the process of the spiral conveying sleeve 33 driving the material toward the output port of the conveying pipe 2, the washing liquid is sprayed through the flushing nozzle 21 to wash the material; the washed material continues to be conveyed toward the output port of the conveying pipe 2; the washing liquid passes through the isolation filter screen 22 and is discharged downwards; so that during the material conveying process, the material can be fed in batches on the one hand, and the material can be washed on the other hand.

[0120] Meanwhile, the second telescopic member 72 facilitates the downward movement of the locking plug 73. As the locking plug 73 moves downward, it is pulled away from the range of the limiting slide groove 341, so that the spiral conveying sleeve 33 switches from the locked state to the unlocked state, so that the spiral conveying sleeve 33 can be removed and replaced on the connecting slide shaft 32, thereby facilitating the quick removal and maintenance of the spiral conveying sleeve 33.

[0121] Please refer to the following: Figure 6 and Figure 7 The material conveying device further includes a liquid supply assembly 6, which includes a liquid storage box 61, a liquid supply pump 62, and a diversion box 63. The liquid storage box 61 is fixed at the bottom of the conveying pipe 2 and is aligned and connected to the lower part of the isolation filter screen 22. The liquid supply pump 62 is installed inside the liquid storage box 61, and the input end of the liquid supply pump 62 is connected to the inside of the liquid storage box 61. The diversion box 63 is fixed on the liquid storage box 61. The output end of the liquid supply pump 62 passes through the liquid storage box 61 and is connected to one end of the first connecting pipe 621. The other end of the first connecting pipe 621 is connected to the input end of the diversion box 63. The output end of the diversion box 63 is connected to the input end of the flushing nozzle 21 through the second connecting pipe 631.

[0122] In this embodiment, the second connecting pipe 631 is configured in a one-to-one correspondence with the flushing nozzle 21.

[0123] In this embodiment, the liquid storage box 61 is pre-filled with a washing solution, which can be deionized water.

[0124] In this embodiment, the liquid supply pump 62 is an existing water pump used to directly draw the washing liquid in the storage box 61, and spray the washing liquid into the range of the delivery pipe 2 through the diversion box 63, the second connecting pipe 631 and the rinsing nozzle 21, so as to spray and wash the material.

[0125] During the material conveying process in the conveying pipe 2, the washing liquid is sprayed through the rinsing nozzle 21. After the sprayed washing liquid washes the material, it flows back into the storage box 61 after passing through the isolation filter 22, realizing the circulation of the washing liquid so that it can be reused.

[0126] Please refer to the following: Figure 6 and Figure 7 The liquid supply assembly 6 further includes a rotating cover 64, a second driving member 65, and an activated carbon filter column 66. The rotating cover 64 is rotatably installed inside the distribution box 63. The rotating cover 64 has a docking hole 641, which faces and communicates with the input end of the second connecting pipe 631. The open end of the rotating cover 64 faces and communicates with the first connecting pipe 621. The second driving member 65 is installed on the distribution box 63 and is used to drive the rotating cover 64 to rotate and adjust within the distribution box 63. The input end of the activated carbon filter column 66 passes through the liquid storage box 61 and the distribution box 63 in sequence, and the input end of the activated carbon filter column 66 is aligned with the rotation range of the docking hole 641.

[0127] In this embodiment, the liquid storage box 61 includes two operating modes:

[0128] Circulating liquid supply mode, such as Figure 7 As shown, the docking hole 641 faces the input end of the second connecting pipe 631. After the liquid supply pump 62 draws the washing liquid from the liquid storage box 61, it injects the washing liquid into the rinsing nozzle 21 through the second connecting pipe 631. The rinsing nozzle 21 sprays the washing liquid into the inside of the delivery pipe 2. The washing liquid after rinsing then flows back down into the inside of the liquid storage box 61 through the isolation filter screen 22.

[0129] Circulating purification mode, such as Figure 8 As shown, the docking hole 641 faces the input end of the activated carbon filter column 66. After the liquid supply pump 62 draws the washing liquid from the storage box 61, it filters and purifies the washing liquid through the activated carbon filter column 66 and circulates it, so as to facilitate the self-circulation purification treatment of the washing liquid in the storage box 61.

[0130] When the rotating cover 64 is connected to the second connecting pipe 631, the liquid supply pump 62 can conveniently control the water washing liquid in the liquid storage box 61 to enter the rinsing nozzle 21. The rinsing nozzle 21 sprays the water washing liquid into the conveying pipe 2 to facilitate the washing of materials during the transmission process. The washed solution flows downward through the isolation filter screen 22 into the interior of the liquid storage box 61 to facilitate the circulation and spraying of the water washing liquid.

[0131] When the rotating cover 64 is connected to the activated carbon filter column 66, the water washing liquid in the storage box 61 can be easily controlled to circulate through the liquid supply pump 62. During the flow, the water washing liquid is self-cleaned and maintained through the activated carbon filter column 66, which extends the service life of the circulating water washing liquid, reduces the discharge of waste liquid, and helps to promote energy conservation and environmental protection.

[0132] In this embodiment, the second driving component 65 can be a motor structure, used to directly drive the rotating cover 64 to rotate and adjust, thereby facilitating the switching of the working mode of the liquid storage box 61.

[0133] In an optional embodiment of this example, two activated carbon filter columns 66 are provided, and the two activated carbon filter columns 66 are respectively aligned within the rotation range of the two docking holes 641.

[0134] Please refer to the following: Figure 3 and Figure 7 The bottom of the liquid storage box 61 is provided with a liquid exchange pipe 611, and the liquid exchange pipe 611 is provided with an independent control valve.

[0135] The washing solution can be easily replaced and maintained via the fluid exchange tube 611.

[0136] Please refer to the following: Figure 1 and Figure 2 The support assembly 1 includes a base 11, a support frame 12, and a first telescopic member 13. The bottom of the support frame 12 is fixed on the base 11. One end of the conveying pipe 2 is rotatably mounted on the support frame 12. The fixed part of the first telescopic member 13 is hinged to the base 11, and the telescopic part of the first telescopic member 13 is hinged to the other end of the conveying pipe 2.

[0137] In this embodiment, the first telescopic member 13 can be a hydraulic telescopic cylinder, used to directly drive the conveying pipe 2 to rotate and adjust on the support frame 12, so as to adjust the tilt angle of the conveying pipe 2.

[0138] The first telescopic member 13 allows the output end of the conveying pipe 2 to be lifted upwards, so that the conveying pipe 2 is used in an inclined state, preventing the washing liquid from flowing out of the output end of the conveying pipe 2 and ensuring the stability of the washing liquid flowing back into the liquid storage box 61 through the isolation filter 22.

[0139] The working principle of the material conveying device provided in this embodiment is as follows:

[0140] Let's define it as follows: In the initial state, the spiral conveying sleeve 33 is in a locked state, and the liquid storage box 61 is in a circulating liquid supply mode;

[0141] A1, Material transfer: The material to be washed is put into the inside of the feed pipe 4, the first drive unit 31 is started, the first drive unit 31 drives the connecting slide shaft 32 to rotate, the connecting slide shaft 32 drives the spiral conveying sleeve 33 to rotate, and the spiral conveying sleeve 33 can carry the material entering the conveying pipe 2 for transfer when it rotates.

[0142] While the connecting slide shaft 32 rotates, the transmission component 5 also drives the feeding impeller 41 to rotate. The feeding impeller 41 drives the material in the feed pipe 4 to rotate downward and be conveyed, which facilitates the material to be fed in batches.

[0143] A2, material washing: Start the liquid supply pump 62. The liquid supply pump 62 draws the washing liquid in the liquid storage box 61 and transfers it into the first connecting pipe 621. The washing liquid enters the interior of the rotating cover 64 and enters the interior of the rinsing nozzle 21 after passing through the docking hole 641 and the second connecting pipe 631. The rinsing nozzle 21 sprays the washing liquid into the interior of the conveying pipe 2. After the washing liquid is sprayed, the material is washed.

[0144] The washed material continues to be conveyed to the output port of the conveying pipe 2 through the spiral conveyor sleeve 33;

[0145] After rinsing, the washing liquid flows back down through the isolation filter 22 to the interior of the liquid storage box 61, so as to realize the circulation and return of the washing liquid in the liquid storage box 61;

[0146] A3, please refer to the reference. Figures 7 to 8 The washing liquid is purified, the second driving component 65 is activated, the second driving component 65 drives the rotating cover 64 to rotate, the rotating cover 64 drives the docking hole 641 to rotate, so that the docking hole 641 rotates toward the input end of the activated carbon filter column 66 and is connected, so that the liquid storage box 61 switches from the circulating liquid supply mode to the circulating purification mode.

[0147] Purification principle: The liquid supply pump 62 draws the washing liquid from the liquid storage box 61. The washing liquid passes through the first connecting pipe 621, the rotating cover 64, the docking hole 641 and the activated carbon filter column 66 in sequence. The activated carbon filter column 66 filters and purifies the washing liquid, reduces impurities in the washing liquid, extends the service life of the washing liquid, and facilitates the self-circulation and purification of the washing liquid.

[0148] A4, Maintenance of the spiral conveying sleeve 33: Activate the second telescopic member 72, which drives the locking plug 73 to move downwards. The locking plug 73 moves downwards and gradually moves away from the range of the limiting slide groove 341 until the locking plug 73 is completely pulled out of the limiting slide groove 341, so that the spiral conveying sleeve 33 switches from the locked state to the unlocked state, so that the spiral conveying sleeve 33 can be pulled out from the output direction of the conveying pipe 2. After being pulled out, the surface of the spiral conveying sleeve 33 can be maintained.

[0149] Second embodiment:

[0150] Please refer to the following: Figures 9 to 10 Based on the material conveying device provided in the first embodiment of the present invention, the second embodiment of the present invention proposes another material conveying device. The second embodiment is merely a preferred embodiment of the first embodiment, and the implementation of the second embodiment will not affect the separate implementation of the first embodiment.

[0151] Specifically, the difference in the material conveying device provided in the second embodiment of the present invention is that the second driving member 65 may not be a motor structure.

[0152] The second driving component 65 includes a synchronous shaft 651 and a gear 652. One end of the synchronous shaft 651 passes through the distributor box 63 and is fixedly connected to the rotating cover 64. The other end of the synchronous shaft 651 is fixedly connected to the gear 652.

[0153] A rack 731 is fixedly provided on the locking plug 73, and the rack 731 is meshed with the gear 652. The rack 731 has an L-shaped structure.

[0154] When the second telescopic member 72 controls the locking plug 73 to move downward, the locking plug 73 can also drive the rack 731 to move downward. The rack 731 drives the gear 652 to rotate, the gear 652 drives the synchronous shaft 651 to rotate, and the synchronous shaft 651 drives the rotating cover 64 to rotate, so that the rotating cover 64 drives the docking hole 641 to rotate adaptively.

[0155] So that during the process of the locking plug 73 switching from the locked state to the unlocked state, the liquid storage box 61 can be controlled to switch from the circulating liquid supply mode to the circulating purification mode; so that the state switching power of the locking plug 73 can be used to realize the switching of the liquid storage box 61 mode.

[0156] The working principle of a material conveying device provided in this embodiment is as follows:

[0157] Let's define it as follows: In the initial state, the locking plug 73 is in a locked state, and the liquid storage box 61 is in a circulating liquid supply mode.

[0158] When only the operating mode of the liquid storage box 61 needs to be controlled, refer to the following: Figure 12 (a) to Figure 12 (b) and Figure 12 (d) to Figure 12 In step (f), the second telescopic member 72 is activated, which drives the locking plug 73 to move downward. Simultaneously, the locking plug 73 moves downward, driving the rack 731 to move downward. The rack 731 drives the gear 652 to rotate, and the gear 652 drives the rotating cover 64 to rotate synchronously through the synchronous shaft 651. The docking hole 641 rotates and separates from the second connecting pipe 631, causing the second connecting pipe 631 to close automatically.

[0159] The docking hole 641 faces and is connected to the input end of the activated carbon filter column 66, so that the washing liquid flows back to the interior of the liquid storage box 61 after being filtered by the activated carbon filter column 66. However, the locking plug 73 is not completely withdrawn from the limiting slide groove 341 to maintain the locking of the docking slide 34.

[0160] When it is necessary to remove the spiral conveyor sleeve 33, refer to the following: Figure 12 (b) to Figure 12 (c) and Figure 12 (e) to Figure 12 In (f), the second telescopic member 72 is activated again. The second telescopic member 72 drives the locking plug 73 to move down. The locking plug 73 moves down and is completely pulled out of the range of the limiting slide groove 341, so that the spiral conveying sleeve 33 switches from the locked state to the unlocked state, so that the spiral conveying sleeve 33 can be quickly removed from the connecting slide shaft 32.

[0161] As the locking plug 73 moves downward, the gear 652 drives the rotating cover 64 to rotate synchronously through the synchronous shaft 651, and the rotating cover 64 drives the docking hole 641 to maintain communication with the activated carbon filter column 66.

[0162] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for extracting lithium from lepidolite based on sodium sulfide, characterized in that, Includes the following steps: Step S1: The lithium mica is fed into a planetary ball mill for grinding and crushing. The crushed material is then screened to obtain screened material. Step S2: Mix the screening material and anhydrous sodium sulfide evenly at a weight ratio of 1:1 to 3. The mixture is subjected to high-intensity grinding, and the chemical reaction between lepidolite and anhydrous sodium sulfide is initiated by mechanical energy to obtain the reactant material; Step S3: Add the reactants to deionized water at a slurry density of 20 g / L, and perform leaching to dissolve the activated lithium into the aqueous solution; separate the leachate and filter residue using a filtration device. Step S4: Add H2O2 solution to the leachate at a volume ratio of 1:30~50, stir for 30 minutes, and remove Fe. 2+ Oxidized to Fe 3+ Adjust the pH with ammonia, let stand for 1 hour, and allow the Fe... 3+ Hydrolysis produces a flocculent precipitate of Fe(OH)3, which is filtered to remove impurities and then settled. Step S5: Add saturated Na2CO3 solution to the settling solution and adjust the pH to 7-8, so that Ca... 2+ Mg 2+ CaCO3 and MgCO3 precipitates are generated and removed; then CO2 is introduced to adjust the pH to 6-7, so that Al... 3+ Al(OH)3 precipitate is generated and removed; both precipitates need to be aged at 80℃ for 1 hour, and the purified solution is obtained after filtration and separation. Step S6: First, pass the impurity removal solution into the resin column, and then elute the resin with 0.5 mol / L HCl to obtain a high-concentration lithium chloride solution. Step S7: Heat the high-concentration lithium chloride solution to 90°C, add saturated Na2CO3 solution at a constant speed while stirring, react to generate Li2CO3 precipitate, keep warm and age for 2 hours; then use a material conveying device to transport and discharge the Li2CO3 precipitate.

2. The method for extracting lithium from lepidolite based on sodium sulfide according to claim 1, characterized in that, In step S1, minerals that pass through a 200-mesh standard sieve but do not reach 200 mesh are returned to the planetary ball mill for cyclic grinding.

3. The method for extracting lithium from lepidolite based on sodium sulfide according to claim 1, characterized in that, The method for preparing anhydrous sodium sulfide in step S2 is to dehydrate sodium sulfide nonahydrate to remove water of crystallization and obtain anhydrous sodium sulfide.

4. The method for extracting lithium from lepidolite based on sodium sulfide according to claim 3, characterized in that, The dehydration process involves calcining at 120°C for 6 hours.

5. The method for extracting lithium from lepidolite based on sodium sulfide according to claim 1, characterized in that, The reaction leaching conditions in step S3 are room temperature, magnetic stirring speed of 500~600 rpm, and leaching time of 30 minutes.

6. The method for extracting lithium from lepidolite based on sodium sulfide according to claim 1, characterized in that, In step S4, the pH is adjusted to 4.0 ± 0.

3.

7. The method for extracting lithium from lepidolite based on sodium sulfide according to claim 1, characterized in that, In step S6, the resin column is a lithium-ion chelating resin column.

8. The method for extracting lithium from lepidolite based on sodium sulfide according to claim 1, characterized in that, In step S7, during the material conveying and discharging process, the precipitate is washed three times with deionized water at 60°C, and then dried in a vacuum drying oven at 110°C for 4 hours.

9. The method for extracting lithium from lepidolite based on sodium sulfide according to claim 1, characterized in that, The material conveying device includes: Support components; A conveying pipe is installed on the support assembly. A flushing nozzle is provided at the top of the conveying pipe, and an isolation filter screen is provided at the bottom of the conveying pipe. The flushing nozzle and the isolation filter screen are aligned vertically. A connection hole is provided on the conveying pipe. A conveying assembly includes a first driving component, a connecting slide shaft, a spiral conveying sleeve, and a docking slide. The fixing part of the first driving component is fixedly disposed at one end of the conveying pipe. One end of the connecting slide shaft passes through the conveying pipe and is fixedly connected to the driving part of the first driving component. The spiral conveying sleeve is keyed on the connecting slide shaft. The docking slide is fixed on the spiral conveying sleeve and slidably disposed inside the conveying pipe. A limit groove is formed on the docking slide. A feed pipe is provided at the top of the conveying pipe, and a feed impeller is rotatably installed inside the feed pipe. The output end of the feed pipe is connected to the inside of the conveying pipe. A transmission component, which passes through the connecting hole and drives the connecting slide shaft and the feeding impeller; The locking assembly includes a connecting frame, a second telescopic member, and a locking plug. The connecting frame is fixed on the conveying pipe, the fixing part of the second telescopic member is fixed on the connecting frame, the bottom of the locking plug is fixedly connected to the telescopic part of the second telescopic member, and the top of the locking plug penetrates the conveying pipe and is inserted into the limiting groove.

10. A method for extracting lithium from lepidolite based on sodium sulfide according to claim 9, characterized in that, The material conveying device further includes a liquid supply assembly, which includes a liquid storage box, a liquid supply pump, and a diversion box. The liquid storage box is fixed at the bottom of the conveying pipe and is aligned with the lower part of the isolation filter. The liquid supply pump is installed inside the liquid storage box, and its input end is connected to the inside of the liquid storage box. The diversion box is fixed on the liquid storage box, and its output end passes through the liquid storage box and is connected to one end of a first connecting pipe. The other end of the first connecting pipe is connected to the input end of the diversion box, and the output end of the diversion box is connected to the input end of the flushing nozzle through a second connecting pipe.

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