Treatment system for lithium-containing wastewater

Abstract

The invention discloses a lithium-containing wastewater treatment system, and relates to the field of sewage treatment.The lithium-containing wastewater treatment system comprises a reaction liquid discharging mechanism, a mixing mechanism and a spiral girdling gas injection mechanism, the reaction liquid discharging mechanism comprises a first liquid containing part and a liquid control assembly, a plurality of liquid leakage holes are formed in the bottom of the first liquid containing part in a penetrating mode, and a liquid discharging ball is installed in each liquid leakage hole in a rolling mode; the liquid control assembly drives the liquid drainage ball to turn over so as to adapt the speed of the reaction liquid falling into a target object according to the rotating speed, the spiral girdling gas injection mechanism comprises a gas bin body, and a plurality of gas outlet nozzles and elastic spiral guide plates are distributed and mounted on the outer side end face of the gas bin body at equal intervals. Lithium ions are fixed preferentially, influence on subsequent lithium carbonate crystallization caused by premature precipitation of calcium ions and magnesium ions is avoided, and in the later period, sodium carbonate is used for precipitation leading and carbon dioxide is used as assistance to form turbulent flow to promote solution mixing, prevent crystal sedimentation or agglomeration and take away tiny crystal nucleuses.

Description

Technical Field

[0001] The present invention relates to the field of sewage treatment, and specifically to a treatment system for lithium-containing wastewater. Background Art

[0002] With the wide application of lithium-ion batteries in the fields of new energy vehicles, energy storage devices, and consumer electronics, the demand for lithium resources has surged, and the efficient recovery of lithium-containing wastewater has become a key link in resource recycling. At present, the sodium carbonate precipitation method is generally used in industry to recover lithium from lithium-containing wastewater, but this process has significant defects: under alkaline conditions, impurity ions such as calcium and magnesium in the wastewater are easily combined with carbonate ions to form precipitates, co-crystallize with lithium carbonate, resulting in a decrease in product purity; At the same time, traditional processes mostly rely on high-temperature and high-alkali environments, with high energy consumption and prone to local supersaturation, promoting the co-precipitation of microcrystals or impurities, forming fine particles, and affecting the subsequent filtration and washing efficiency. Summary of the Invention

[0003] The purpose of the present invention is to provide a treatment system for lithium-containing wastewater, which utilizes the synergistic effect of carbon dioxide and sodium carbonate, adopts different reaction dominances at different stages, strengthens the mass transfer efficiency and realizes impurity inhibition, so as to improve the lithium recovery rate, reduce the production cost and improve the product quality, and solve the problems raised in the above background art.

[0004] To achieve the above purpose, the present invention provides the following technical solution: A treatment system for lithium-containing wastewater, including a reaction liquid discharge mechanism, a mixing mechanism, and a spiral circumferential cutting gas injection mechanism. The reaction liquid discharge mechanism includes a first liquid loading member and a liquid control component. A number of liquid leakage holes are distributed and penetrated at the bottom of the first liquid loading member, and a liquid discharge ball is rotatably installed in each liquid leakage hole. The liquid control component drives the liquid discharge ball to flip to adapt the falling speed of the reaction liquid to the target according to the rotation speed. The spiral circumferential cutting gas injection mechanism includes a gas storage body, and a number of gas outlet nozzles and elastic spiral guide plates are equidistantly distributed and installed on the outer end face of the gas storage body. The gas outlet nozzles are interconnected with the internal gas cavity of the gas storage body, and the gas outlet of the gas outlet nozzle faces the elastic spiral guide plate. An angle adjustment component is provided between the mixing mechanism and the spiral circumferential cutting gas injection mechanism. The angle adjustment component adjusts the inclination angle of the elastic spiral guide plate in real time according to the rotation speed of the spiral circumferential cutting gas injection mechanism, so as to adapt the injection angle of the reaction gas into the target at different rotation speeds, and dynamically adjust and control the synergy between the reaction liquid and the reaction gas by using the rotation speed.

[0005] Preferably, the liquid control assembly includes a liquid control frame. Connecting rods are distributed and installed on the lower end surface of the liquid control frame. A double-ring drive is fixedly installed at the bottom of the connecting rod. The double-ring drive is in close contact with the outer end surface of the liquid discharge ball. A slot is provided at the top of the liquid discharge ball. The rotation of the double-ring drive drives the liquid discharge ball to flip, so that the slot is flipped to the bottom to realize the fall of the reaction liquid.

[0006] Preferably, the mixing mechanism includes a central cylinder and an outer fixed ring. Connecting parts are respectively arranged at the bottom end and the top end of the central cylinder. A number of stirring parts are equidistantly distributed and connected between the connecting parts and the outer fixed ring.

[0007] Preferably, the spiral cutting gas injection mechanism further includes a connecting sleeve ring part. A fixed connection is made between the outer end surface of the connecting sleeve ring part and the inner end surface of the top of each elastic spiral guide plate.

[0008] Preferably, the angle adjustment assembly includes a guide slide bar fixedly installed between the central cylinder and the outer fixed ring. A counterweight is slidably connected to the guide slide bar. A slide plate part is slidably connected to the connecting part at the bottom end of the central cylinder. A connecting part is connected between the hinge part of the slide plate part and the counterweight. The bottom end of the slide plate part is fixedly installed on the upper end surface of the connecting sleeve ring part.

[0009] Preferably, the stirring part includes a mixing and stirring part on the upper side and a bubble dispersing part on the lower side.

[0010] Preferably, the mixing and stirring part has a columnar structure with a fan-shaped cross-section, and the bubble dispersing part has an intertwined mesh plate structure. The bubble dispersing part is fixed on the mixing and stirring part.

[0011] Preferably, a top cover is installed on the upper end surface of the first liquid loading part. A liquid supplement pipe is installed on the upper end of the top cover. The bottom of the liquid supplement pipe penetrates into the inner cavity of the first liquid loading part, and the reaction liquid is supplemented through the liquid supplement pipe.

[0012] Preferably, a servo motor is fixedly installed on the upper end surface of the top cover. The output end of the servo motor is fixedly connected to a main shaft. A fixed connection is made between the liquid control frame and the main shaft.

[0013] Preferably, it further includes a stirring kettle. An air injection pipe is installed at the bottom of the stirring kettle. The air injection pipe extends upward and penetrates into the air cavity of the air storage body.

[0014] In summary, the beneficial effects of the present invention are: 1. In the initial stage of lithium carbonate production, the present invention mainly fixes lithium ions by carbonating with carbon dioxide first, avoiding premature precipitation of impurities such as calcium ions and magnesium ions, which may affect subsequent lithium carbonate crystallization. At the same time, it can also reduce the retention of sodium to a certain extent. Subsequently, it switches to precipitation mainly with sodium carbonate solution, and high-speed stirring is assisted by carbon dioxide to significantly improve the mass transfer efficiency. The sodium carbonate solution and the lithium-rich solution are quickly mixed, and lithium ions are rapidly precipitated directly through the reaction, shortening the reaction time. At the same time, carbon dioxide is used to maintain the pH of the reaction system, promoting each other with the low-speed stirring in the initial stage, accurately avoiding the precipitation windows of CaCO3 and MgCO3, thus greatly reducing the precipitation of impurities into the lithium carbonate precipitate. Moreover, CO2 bubbles quickly rise under high-speed stirring, forming turbulence, promoting solution mixing, preventing crystal sedimentation or aggregation, and taking away tiny crystal nuclei, inhibiting secondary nucleation. The CO2 microenvironment can adjust the crystal surface energy, guiding the growth of lithium carbonate along specific crystal planes, forming regular rhombic or flaky crystals, improving the product processing performance, and making the particles of lithium carbonate crystals all distributed as large particles; 2. Resource recycling and cost advantages: Unreacted carbon dioxide is recovered through top exhaust, dried and compressed, and then reinjected, reducing gas procurement costs; The carbonation path replaces part of the sodium carbonate demand, reducing the consumption of sodium carbonate by 0.3 - 0.5 tons per ton of lithium carbonate; The carbonation stage operates at room temperature, saving 20% - 30% energy compared with the traditional high-temperature and high-alkali process. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 It is a schematic structural diagram of a treatment system for lithium-containing wastewater according to the present invention; Figure 2 It is a front sectional view structural diagram of a treatment system for lithium-containing wastewater according to the present invention; Figure 3 It is a schematic structural diagram of a reaction liquid discharge mechanism, a mixing mechanism and a spiral circumferential cutting gas injection mechanism in a treatment system for lithium-containing wastewater according to the present invention; Figure 4 It is a bottom perspective view structural diagram of a reaction liquid discharge mechanism, a mixing mechanism and a spiral circumferential cutting gas injection mechanism in a treatment system for lithium-containing wastewater according to the present invention; Figure 5 It is an enlarged structural diagram of a spiral circumferential cutting gas injection mechanism in a treatment system for lithium-containing wastewater according to the present invention; Figure 6 This is a partially enlarged structural schematic diagram of the reaction liquid discharge mechanism in a lithium-containing wastewater treatment system of the present invention; Figure 7 This is an unfolded structural schematic diagram of the reaction liquid discharge mechanism in a lithium-containing wastewater treatment system of the present invention; Figure 8 This is a partially enlarged structural schematic diagram of the tank hole in a lithium-containing wastewater treatment system of the present invention; Figure 9 This is a structural schematic diagram of the stirring member in a lithium-containing wastewater treatment system of the present invention.

[0017] The reference numerals in the drawings are described separately as follows: reaction liquid discharge mechanism 2; mixing mechanism 3; spiral cutting and gas injection mechanism 4; stirring kettle 10; support frame 11; top cover 12; liquid supply pipe 13; servo motor 14; liquid discharge pipe 15; gas injection pipe 16; main shaft 17; first liquid loading member 20; liquid control frame 21; double-ring driving member 22; connecting rod 23; liquid leakage hole 24; liquid discharge ball 25; tank hole 26; central cylinder 30; outer ring fixing ring 31; stirring member 32; guiding slide bar 33; counterweight member 34; connecting member 35; sliding plate member 36; gas storage body 40; gas outlet nozzle 41; elastic spiral guide plate 42; connecting sleeve ring member 44. Detailed Description of the Invention

[0018] Now, the present invention will be further described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. These drawings are all simplified schematic diagrams, only illustrating the basic structure of the present invention in a schematic manner, and therefore only showing the components related to the present invention.

[0019] To facilitate the understanding of the present invention, the present invention will be described more comprehensively with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0020] All the features disclosed in this specification, or all the steps in the disclosed methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

[0021] Any feature disclosed in this specification (including any additional claims, abstract, and drawings), unless specifically stated, can be replaced by other equivalent or similar-purpose alternative features. That is, unless specifically stated, each feature is only an example of a series of equivalent or similar features.

[0022] In the present invention, unless otherwise clearly specified or limited, terms such as "installation", "connection", "linkage", "fixation", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, and it may be the communication inside at least two elements or the interaction relationship between at least two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] The following will Figures 1-9 describe the present invention in detail. For the convenience of narration, the orientations mentioned below are defined as follows: the up-down, left-right, front-back directions mentioned below are the same as the front-back, left-right, up-down directions of the Figure 2 viewing direction, Figure 2 which is the front view of the device of the present invention, Figure 2 and the directions shown are the same as the front-back, left-right, up-down directions of the front view direction of the device of the present invention.

[0024] Please refer to Figures 1-9 , an embodiment provided by the present invention: the main pollutants in lithium-containing wastewater are lithium ions, other coexisting ions (such as Na + , K + , Ca 2+ , Mg 2+ ), organic matter, suspended solids, etc. In the process of treating lithium-containing wastewater, impurities need to be removed by pretreatment first, and then lithium ions are selectively enriched to form a high-concentration lithium solution. To form lithium carbonate crystals, a saturated sodium carbonate solution needs to be added. Lithium carbonate is used as the cathode material for manufacturing lithium-ion batteries, such as lithium cobaltate, nickel cobalt manganese ternary material, nickel cobalt aluminum ternary material, etc. With the rapid development of electric vehicles, portable electronic devices and energy storage systems, the demand for lithium carbonate continues to grow. In the traditional process of using sodium carbonate solution to produce lithium carbonate, we found that during low-speed stirring, it is easy for the sodium carbonate solution to be locally over-concentrated in the enriched lithium-ion solution, leading to rapid nucleation, forming microcrystals or impurity co-precipitation. During high-speed stirring, the sodium carbonate solution can be quickly dispersed, avoiding local supersaturation and resulting in too many crystal nuclei and generating fine particles. These phenomena will seriously affect the production of lithium carbonate. Therefore, a treatment system for lithium-containing wastewater is used to double-cooperate to produce lithium carbonate by introducing carbon dioxide at the bottom of the solution enriched with lithium ions and adding a saturated sodium carbonate solution at the top; Refer to Figure 1 and Figure 2, specifically including a stirring kettle 10, a reaction liquid discharging mechanism 2, a mixing mechanism 3 and a spiral circumferential cutting gas injection mechanism 4. A top cover 12 is installed at the opening position at the top of the stirring kettle 10. A servo motor 14 is installed on the upper end surface of the top cover 12. The output end of the servo motor 14 is fixedly connected to a main shaft 17. The servo motor 14 serves as the main power output for mixing and stirring. The reaction liquid discharging mechanism 2, the mixing mechanism 3 and the spiral circumferential cutting gas injection mechanism 4 are all connected to the main shaft 17. The reaction liquid discharging mechanism 2 is installed at the top, the spiral circumferential cutting gas injection mechanism 4 is installed at the bottom, and the mixing mechanism 3 is installed between the reaction liquid discharging mechanism 2 and the spiral circumferential cutting gas injection mechanism 4. The enriched lithium-ion solution to be processed is introduced into the inner cavity of the stirring kettle 10. The saturated sodium carbonate solution is added as the reaction liquid from the surface of the lithium-ion solution. Carbon dioxide is used as the reaction gas in the spiral circumferential cutting gas injection mechanism 4 at the bottom and is injected into the lithium-ion solution along the circumferential cutting direction. When the mixing speed is relatively slow, the circumferential cutting angle of the carbon dioxide injected from the bottom is small, ensuring the residence time of the carbon dioxide in the lithium-ion solution. When the mixing speed is low, the addition amount of the sodium carbonate solution at the top is also small. Thus, the reaction mainly relies on carbon dioxide and is supplemented by the reaction of the sodium carbonate solution. During the process of the carbon dioxide gradually rising in the lithium-ion solution, it will disturb the solution, promote mass transfer, reduce crystal agglomeration, and promote the growth of large-sized crystals. At the same time, it can effectively inhibit the formation of CaCO3 and MgCO3 precipitates, generate LiHCO3 through the CO2 carbonization path, and then pyrolyze to Li2CO3 while also generating carbon dioxide. The carbon dioxide generated by pyrolysis will be added to the reaction when the mixing and stirring speed increases in the later stage. When the mixing speed is increased in the later stage, the addition amount of the sodium carbonate solution added in the reaction liquid discharging mechanism 2 at the top also increases with the increase in speed. At this time, the circumferential cutting angle of the carbon dioxide injection in the spiral circumferential cutting gas injection mechanism 4 at the bottom becomes larger with the faster speed, reducing the residence time of the carbon dioxide in the lithium-ion solution. Thus, a situation where the sodium carbonate solution is the main component and the carbon dioxide reaction is the auxiliary component is formed. Utilizing the rapid rise of the carbon dioxide bubbles further promotes mass transfer and inhibits the adsorption of impurities onto the crystal surface, greatly accelerating the reaction efficiency, increasing the unit production capacity while obtaining large-sized lithium carbonate crystals with uniform distribution, thus facilitating the subsequent filtration and washing.

[0025] Reference Figure 3 , Figure 7 , Figure 8 And Figure 9, It is worth mentioning that, in this embodiment, the reaction liquid discharging mechanism 2 includes a first liquid loading member 20, the top cover 12 is installed on the top of the first liquid loading member 20, and a number of liquid leakage holes 24 are distributed and penetrated through the bottom of the first liquid loading member 20. A liquid discharging ball 25 is rotatably installed in each liquid leakage hole 24. The saturated sodium carbonate reaction liquid for the reaction is in the inner cavity of the first liquid loading member 20. The sodium carbonate solution is brought to the bottom position of the first liquid loading member 20 by the rolling of the liquid discharging ball 25 and then falls. In order to further ensure the falling of the solution, a slot hole 26 is provided on the liquid discharging ball 25. During the rolling cycle of the liquid discharging ball 25, when the slot hole 26 is in the sodium carbonate solution, it will collect the solution. When it rolls to the bottom, due to the action of centrifugal force and gravity, the sodium carbonate solution will be put into the solution enriched with lithium ions. A liquid control frame 21 is fixedly installed on the main shaft 17. Connecting rods 23 are distributed and installed on the lower end surface of the liquid control frame 21. A double-ring driving member 22 is fixedly installed at the bottom of the connecting rod 23. The double-ring driving member 22 is in close contact with the outer end surface of the liquid discharging ball 25. The rotation of the double-ring driving member 22 drives the liquid discharging ball 25 to turn over, so that the slot hole 26 is turned to the bottom to realize the falling of the reaction liquid. When the stirring speed is faster, the rolling and turning speed of the liquid discharging ball 25 is also faster, so that the falling speed of the reaction liquid is also faster, so that the amount of the reaction liquid can always match the stirring speed at any time.

[0026] Reference Figure 3 , Figure 4 And Figure 5, It is also worth mentioning that in this embodiment, the spiral circumferential cutting gas injection mechanism 4 includes a gas storage body 40. The top of the gas storage body 40 is fixedly connected to the main shaft 17. The gas storage body 40 is installed at the bottom of the stirring kettle 10. A gas injection pipe 16 is installed at the bottom of the stirring kettle 10. The gas injection pipe 16 extends upward and penetrates into the gas cavity inside the gas storage body 40 to provide a sufficient amount of carbon dioxide reaction gas for the reaction. A number of gas outlet nozzles 41 and elastic spiral guide plates 42 are equidistantly distributed and installed on the outer end face of the gas storage body 40. A connecting collar 44 is slidably connected to the main shaft 17. The outer end face of the connecting collar 44 is fixedly connected to the inner end face of the top of each elastic spiral guide plate 42. The gas outlet nozzles 41 communicate with the internal gas cavity of the gas storage body 40. The gas outlet of the gas outlet nozzle 41 faces the elastic spiral guide plate 42, so that carbon dioxide gas is guided along the elastic spiral guide plate 42 and injected into the solution. An angle adjustment component is provided between the mixing mechanism 3 and the spiral circumferential cutting gas injection mechanism 4. The angle adjustment component adjusts the inclination angle of the elastic spiral guide plate 42 in real time according to the rotation speed of the spiral circumferential cutting gas injection mechanism 4, so as to realize the angle at which the reaction gas is adaptively injected into the target object at different rotation speeds, and use the rotation speed to dynamically adjust and control the coordinated cooperation of the reaction liquid and the reaction gas.

[0027] Reference Figure 3 , Figure 4 And Figure 9 , It should be noted that in this embodiment, the mixing mechanism 3 includes a central cylinder 30 and an outer fixed ring 31. Connecting parts are respectively arranged at the bottom end and the top end of the central cylinder 30. A number of stirring parts 32 are equidistantly distributed and connected between the connecting parts and the outer fixed ring 31, so that the stirring parts 32 are inclined at both upper and lower positions, and can be fully mixed and stirred to accelerate the reaction.

[0028] Reference Figure 3 , Figure 4 And Figure 5, It should also be noted that in this embodiment, the angle adjustment assembly includes a guiding slide bar 33 fixedly installed between the central cylinder 30 and the outer ring fixing ring 31. A counterweight 34 is slidably connected to the guiding slide bar 33. A sliding plate member 36 is slidably connected to the connecting portion at the bottom end of the central cylinder 30. A connecting member 35 is connected between the hinged portion of the sliding plate member 36 and the counterweight 34. The bottom end of the sliding plate member 36 is fixedly installed on the upper end surface of the connecting sleeve member 44. When the rotation speed during mixing becomes faster, the counterweight 34 will slide outward along the guiding slide bar 33 due to centrifugal force, thereby pulling the sliding plate member 36 to slide upward, causing the elastic spiral guide plate 42 to lift upward. After the elastic spiral guide plate 42 is lifted, the inclination angle of the entire end becomes larger, so that the circumferential cutting angle of carbon dioxide injection becomes larger, allowing carbon dioxide to quickly pass through the lithium ion solution, reducing the residence time in the solution, and then being discharged through the gas outlet pipe at the top for recycling. Since the elastic spiral guide plate 42 itself has elasticity, when the rotation speed decreases, the elastic spiral guide plate 42 will reset.

[0029] Reference Figure 9 , and in order to further disperse the carbon dioxide gas to improve the contact with the lithium ion solution, in this embodiment, the stirring member 32 includes a mixing and stirring part on the upper side and a bubble dispersing part on the lower side. The mixing and stirring part has a columnar structure with a fan-shaped cross-section, and the bubble dispersing part has an intertwined mesh plate structure. The mesh plate structure is exactly located above the injection of carbon dioxide gas. During the mixing and stirring process, the stirring member 32 rotates, and the mesh is used to disperse carbon dioxide to ensure the reaction surface of carbon dioxide.

[0030] In addition, in one embodiment, a top cover 12 is installed on the upper end surface of the first liquid loading member 20. A liquid supplement pipe 13 is installed on the upper end of the top cover 12. The bottom of the liquid supplement pipe 13 penetrates into the inner cavity of the first liquid loading member 20, and the reaction liquid is supplemented through the liquid supplement pipe 13.

[0031] During specific operation: Initial parameters and preparation stage Raw materials: Lithium-containing wastewater: Li + Concentration 12 g / L, containing Na + 3 g / L, Ca 2+ 50 mg / L, suspended solids 200 mg / L; After pretreatment: After precipitation, filtration, and ion exchange, a large amount of Ca 2+ , Mg 2+ are removed, and the concentration of Li + is increased to 18 g / L, and the pH is adjusted to 3.0 (acidic leaching solution); The volume of the stirring kettle 10 is 2000 L; The initial stirring speed is controlled at 50 rpm (low-speed stage), and the temperature is controlled at 25 °C (room temperature), with carbonization being the dominant process; CO2 flow rate: 0.8 L / min. It enters the gas storage body 40 through the injection pipe 16 and is injected into the solution spirally along the guide plate through the outlet nozzle 41. At this time, due to the relatively low speed, the inclination angle of the elastic spiral guide plate 42 is approximately 15°. At this time, the residence time of CO2 in the solution is about 5 minutes, and the reaction path with the lithium-ion solution is as follows: ; The pH rises from the initial 3.0 to 6.5, and it is still in a weakly acidic environment. At the same time, the reaction liquid discharge mechanism 2 at the top injects saturated sodium carbonate solution. The rolling speed of the drainage ball 25 is about 5 revolutions per minute, and the addition amount of sodium carbonate solution is 0.6 times the theoretical value (about 1.8 L / h). The mesh bubble breakup part of the stirring member 32 cuts and breaks up the CO2 bubbles, increasing the gas-liquid contact area, and at the same time mixing and stirring, making the lithium-ion solution gradually turbid and generating LiHCO3 intermediate. Since it is in a weakly acidic environment, Ca 2+ is not easy to precipitate, inhibiting the formation of CaCO3.

[0032] When the concentration of LiHCO3 reaches 15 g / L detected by on-line conductivity monitoring, the system automatically increases the speed to 300 rpm, enters the later high-speed mixing and stirring stage, and switches to precipitation being the dominant process; At this time, the rolling speed of the drainage ball 25 is increased to 15 revolutions per minute, and the dosing amount of sodium carbonate solution is increased to 1.2 times the theoretical value (about 3.6 L / h). At the same time, the increase in speed causes the counterweight member 34 to move outward due to centrifugal force, pulling the sliding plate member 36 upward, and the inclination angle of the elastic spiral guide plate 42 increases to about 45°; The CO2 flow rate is adjusted to 2.5 L / min, and the bubble rising time is shortened to 1 minute, greatly reducing the residence time of carbon dioxide in the solution. At the same time, the heating system is started, and the solution temperature rises from 25 °C to 95 °C. Since the amount of sodium carbonate added increases, the pH of the solution rises to 10.5, and the reaction path switches to: ; The carbon dioxide generated by pyrolysis is collected through the top exhaust pipe for unreacted CO2, and after condensation and drying, it is reinjected into the gas storage body 40. During the mixing and stirring process, the fan-shaped mixing and stirring part generates strong shear force, evenly dispersing sodium carbonate to prevent local supersaturation. When the light transmittance of the solution > 95% is detected, it indicates that the precipitation is complete, then the stirring is stopped, the discharge valve at the bottom is opened, and the liquid is discharged through the drain pipe 15, and finally filtration and washing are carried out.

[0033] In the initial stage of the mixed reaction, since there is still a certain amount of calcium ions and magnesium ions in the lithium ion solution, carbonation with carbon dioxide is the dominant reaction in the initial stage to improve lithium selectivity and reduce impurity coprecipitation. Under low-speed stirring, the residence time of carbon dioxide in the solution is extended, and it is fully dissolved to form bicarbonate, which combines with lithium ions to form lithium bicarbonate. This reaction is less sensitive to impurity ions such as calcium and magnesium because their carbonates are not easily precipitated under acidic to neutral conditions. Therefore, lithium can be preferentially fixed in the carbonation stage + , avoiding premature coprecipitation of impurities and effectively reducing the introduction of sodium ions. In the later stage, the stirring is switched to high speed, and precipitation with sodium carbonate is the dominant reaction, supplemented by the synergistic effect of carbon dioxide. High-speed stirring significantly enhances the mass transfer efficiency. The sodium carbonate solution and the lithium-rich solution are quickly mixed, and the rapid precipitation of lithium ions is directly achieved through the reaction, shortening the reaction time (the single-batch production cycle can be shortened by 30%-50%). With the assistance of carbon dioxide, it prevents the pH from being too high (>12) from causing precipitation of impurities such as 3+ Al 2- and SiO3.

[0034] Maintaining the reaction system within the optimal range of pH 10-11, thus promoting each other with the low-speed stirring in the initial stage, precisely avoiding the precipitation windows of CaCO3 and MgCO3, thereby greatly reducing the precipitation of impurities mixed into the lithium carbonate precipitate. Moreover, the CO2 bubbles quickly rise under high-speed stirring, forming turbulence, promoting solution mixing, preventing crystal settlement or agglomeration, and at the same time carrying away tiny crystal nuclei and inhibiting secondary nucleation. The CO2 microenvironment can adjust the crystal surface energy, guiding the growth of lithium carbonate along specific crystal planes to form regular rhombic or flaky crystals (SEM observation results), improving the product processing performance and making the particles of lithium carbonate crystals all large-particle distributions.

[0035] As described above, it is only the specific implementation manner of the invention, but the protection scope of the invention is not limited thereto. Any change or substitution that comes to mind without creative labor should be covered within the protection scope of the invention. Therefore, the protection scope of the invention should be subject to the protection scope defined by the claims.

Claims

1. A treatment system for lithium-containing wastewater, characterized in that: It includes a reaction liquid discharging mechanism (2), a mixing mechanism (3) and a spiral cutting injection gas mechanism (4). The reaction liquid discharging mechanism (2) includes a first liquid loading member (20) and a liquid control component. A number of liquid leakage holes (24) penetrate through the bottom of the first liquid loading member (20). A liquid discharging ball (25) is rotatably installed in each liquid leakage hole (24). The liquid control component drives the liquid discharging ball (25) to flip to adapt the falling speed of the reaction liquid to the target according to the rotation speed. The spiral cutting injection gas mechanism (4) includes a gas storage body (40). A number of gas outlet nozzles (41) and elastic spiral guide plates (42) are equidistantly distributed and installed on the outer end face of the gas storage body (40). The gas outlet nozzles (41) are communicated with the internal gas cavity of the gas storage body (40). The gas outlet of the gas outlet nozzle (41) faces the elastic spiral guide plate (42). An angle adjustment component is arranged between the mixing mechanism (3) and the spiral cutting injection gas mechanism (4). The angle adjustment component adjusts the inclination angle of the elastic spiral guide plate (42) in real time according to the rotation speed of the spiral cutting injection gas mechanism (4) to realize the angle at which the reaction gas is adapted to be injected into the target at different rotation speeds, and uses the rotation speed to dynamically adjust and control the coordinated cooperation of the reaction liquid and the reaction gas.

2. The treatment system for lithium-containing wastewater according to claim 1, characterized in that: The liquid control component includes a liquid control frame (21). Connecting rods (23) are distributed and installed on the lower end face of the liquid control frame (21). A double-ring driving member (22) is fixedly installed at the bottom of the connecting rod (23). The double-ring driving member (22) is in close contact with the outer end face of the liquid discharging ball (25). A slot hole (26) is opened at the top of the liquid discharging ball (25). The rotation of the double-ring driving member (22) drives the liquid discharging ball (25) to flip, so that the slot hole (26) flips to the bottom to realize the falling of the reaction liquid.

3. The treatment system for lithium-containing wastewater according to claim 2, wherein: The mixing mechanism (3) includes a central cylinder (30) and an outer ring fixing ring (31). Connecting parts are respectively arranged at the bottom end and the top end of the central cylinder (30). A number of stirring parts (32) are equidistantly distributed and connected between the connecting parts and the outer ring fixing ring (31).

4. The treatment system for lithium-containing wastewater according to claim 3, wherein: The spiral cutting injection gas mechanism (4) further includes a connecting sleeve ring part (44). The outer end face of the connecting sleeve ring part (44) is fixedly connected to the inner end face of the top of each elastic spiral guide plate (42).

5. The treatment system for lithium-containing wastewater according to claim 4, wherein: The angle adjustment component includes a guiding slide rod (33) fixedly installed between the central cylinder (30) and the outer ring fixing ring (31). A counterweight member (34) is slidably connected to the guiding slide rod (33). A slide plate part (36) is slidably connected to the connecting part at the bottom end of the central cylinder (30). A connecting member (35) is connected between the hinged part of the slide plate part (36) and the counterweight member (34). The bottom end of the slide plate part (36) is fixedly installed on the upper end face of the connecting sleeve ring part (44).

6. The treatment system for lithium-containing wastewater according to claim 5, wherein: The stirring part (32) includes a mixing and stirring part on the upper side and a bubble dispersing part on the lower side.

7. A treatment system for lithium-containing wastewater according to claim 6, characterized in that: The mixing and stirring part has a columnar structure with a fan-shaped cross-section, and the bubble dispersing part has an intertwined net plate structure, and the bubble dispersing part is fixed on the mixing and stirring part.

8. The treatment system for lithium-containing wastewater according to claim 1, wherein: A top cover (12) is installed on the upper end surface of the first liquid storage part (20), a liquid supplement pipe (13) is installed on the upper end of the top cover (12), and the bottom of the liquid supplement pipe (13) penetrates into the inner cavity of the first liquid storage part (20), and the reaction liquid is supplemented through the liquid supplement pipe (13).

9. The treatment system for lithium-containing wastewater according to claim 1, wherein: It further includes a stirring kettle (10), and an air injection pipe (16) is installed at the bottom of the stirring kettle (10), and the air injection pipe (16) extends upward and penetrates into the air cavity of the air storage body (40).

10. The treatment system for lithium-containing wastewater according to claim 1, wherein: A servo motor (14) is fixedly installed on the upper end surface of the top cover (12), the output end of the servo motor (14) is fixedly connected to a main shaft (17), and the liquid control frame (21) is fixedly connected to the main shaft (17).

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