A treatment system for lithium-containing wastewater

Abstract

The present invention discloses a treatment system for lithium-containing wastewater, which relates to the field of sewage treatment. The system comprises a reaction liquid discharge mechanism, a mixing mechanism and a spiral annular cutting gas injection mechanism. The reaction liquid discharge mechanism comprises a first liquid-filling part and a liquid control component. A plurality of leakage holes are distributed and passed through the bottom of the first liquid-filling part. A drainage ball is installed in each leakage hole in a rolling manner. The liquid control component drives the drainage ball to flip to adapt the speed of the reaction liquid falling into the target object according to the rotation speed. The spiral annular cutting gas injection mechanism comprises a gas storage body. A plurality of gas outlet nozzles and elastic spiral guide plates are evenly distributed and installed on the outer end surface of the gas storage body. In the initial stage, the present invention adopts carbon dioxide carbonization as the main method to preferentially fix lithium ions and avoid premature precipitation of calcium ions and magnesium ions to affect subsequent lithium carbonate crystallization. In the later stage, sodium carbonate is used as the main method for precipitation, and carbon dioxide is used as an auxiliary method to form turbulence to promote solution mixing, prevent crystal sedimentation or agglomeration, and take away tiny crystal nuclei.

Description

Technical Field

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

[0002] With the widespread application of lithium-ion batteries in 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. Currently, the sodium carbonate precipitation method is widely used in industry to recover lithium from lithium-containing wastewater, but this process has significant drawbacks: under alkaline conditions, impurity ions such as calcium and magnesium in the wastewater easily combine with carbonate ions to form precipitates, which co-crystallize with lithium carbonate, resulting in reduced product purity;

[0003] At the same time, traditional processes mostly rely on high-temperature and high-alkali environments, which have high energy consumption and are prone to cause local oversaturation, prompting the co-precipitation of microcrystals or impurities to form fine particles, affecting the subsequent filtration and washing efficiency. Summary of the Invention

[0004] 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 leaders at different stages, enhances mass transfer efficiency and achieves impurity suppression, so as to improve lithium recovery rate, reduce production costs and improve product quality, so as to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a treatment system for lithium-containing wastewater, comprising a reaction liquid discharge mechanism, a mixing mechanism and a spiral annular cutting gas injection mechanism, wherein the reaction liquid discharge mechanism comprises a first liquid-filling part and a liquid control component, wherein the bottom of the first liquid-filling part is provided with a plurality of leakage holes, wherein a liquid discharge ball is installed in a rolling manner in each of the leakage holes, and the liquid control component drives the liquid discharge ball to flip so as to adapt the speed of the reaction liquid falling into the target object according to the rotation speed, and the spiral annular cutting gas injection mechanism comprises a gas storage body, wherein the outer end surface of the gas storage body is evenly distributed with liquid discharge holes. Several gas outlet nozzles and elastic spiral guide plates are installed. The gas outlet nozzles are connected to the internal air cavity of the gas storage body. 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 annular 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 annular cutting gas injection mechanism, so as to realize the angle of the reaction gas adapted to be injected into the target object at different rotation speeds, and utilizes the rotation speed to dynamically adjust and control the coordinated cooperation between the reaction liquid and the reaction gas.

[0006] Preferably, the liquid control component includes a liquid control frame, the lower end surface of the liquid control frame is distributedly installed with a connecting rod, the bottom of the connecting rod is fixedly installed with a double-ring driving member, the double-ring driving member is tightly abutted against the outer end surface of the drainage ball, and a slot is provided on the top of the drainage ball. The rotation of the double-ring driving member drives the drainage ball to flip, so that the slot flips to the bottom to realize the falling of the reaction liquid.

[0007] Preferably, the mixing mechanism includes a central tube and an outer fixing ring, the bottom and top ends of the central tube are respectively provided with connecting parts, and a plurality of stirring members are equidistantly connected between the connecting parts and the outer fixing ring.

[0008] Preferably, the spiral annular cutting gas injection mechanism further comprises a connecting collar, the outer end surface of the connecting collar being fixedly connected to the inner end surface of the top of each elastic spiral guide plate.

[0009] Preferably, the angle adjustment assembly includes a guide slide rod fixedly mounted between the center tube and the outer ring fixing ring, a counterweight member is slidably connected to the guide slide rod, a slide plate member is slidably connected to the connecting portion at the bottom end of the center tube, a connecting member is connected between the hinged portion of the slide plate member and the counterweight member, and the bottom end of the slide plate member is fixedly mounted on the upper end surface of the connecting collar member.

[0010] Preferably, the stirring element includes a mixing and stirring portion on the upper side and a bubble breaking portion on the lower side.

[0011] Preferably, the mixing and stirring portion is a columnar structure with a fan-shaped cross section, the bubble breaking portion is an interwoven mesh plate structure, and the bubble breaking portion is fixed on the mixing and stirring portion.

[0012] Preferably, a top cover is installed on the upper end surface of the first liquid-containing part, and a liquid infusion tube is installed on the upper end of the top cover. The bottom of the liquid infusion tube passes through the inner cavity of the first liquid-containing part, and the reaction liquid is replenished through the liquid infusion tube.

[0013] Preferably, a servo motor is fixedly mounted on the upper end surface of the top cover, an output end of the servo motor is fixedly connected to a main shaft, and the liquid control frame is fixedly connected to the main shaft.

[0014] Preferably, a stirring kettle is further included, wherein an air injection pipe is installed at the bottom of the stirring kettle, and the air injection pipe extends upward and passes through the air cavity of the gas storage body.

[0015] In summary, the beneficial effects of the present invention are:

[0016] 1. The present invention adopts carbon dioxide carbonization as the leading method to fix lithium ions in the early stage of generating lithium carbonate, thereby avoiding premature precipitation of impurities such as calcium ions and magnesium ions to affect the subsequent lithium carbonate crystallization, and at the same time reducing the sodium production to a certain extent, and subsequently switches to sodium carbonate solution for precipitation, and the high-speed stirring with the synergistic effect of carbon dioxide significantly improves the mass transfer efficiency, the sodium carbonate solution and the lithium-rich solution are rapidly mixed, and the rapid precipitation of lithium ions is directly achieved through reaction, shortening the reaction time, and at the same time, carbon dioxide is used to maintain the pH of the reaction system, which promotes each other with the initial low-speed stirring, accurately avoids the CaCO3 and MgCO3 precipitation windows, thereby greatly reducing the precipitation of impurities into the lithium carbonate precipitate, and CO2 bubbles rise rapidly under high-speed stirring to form turbulence, promote solution mixing, prevent crystal sedimentation or agglomeration, and take away tiny crystal nuclei to inhibit secondary nucleation. The CO2 microenvironment can adjust the crystal surface energy, guide the lithium carbonate to grow along a specific crystal plane, form regular rhombus or flaky crystals, improve the product processing performance, and make the lithium carbonate crystal particles all large particles.

[0017] 2. Resource recycling and cost advantages: Unreacted carbon dioxide is recovered through top exhaust, dried and compressed, and then reinjected, reducing gas procurement costs;

[0018] The carbonization pathway replaces part of the sodium carbonate demand, reducing sodium carbonate consumption by 0.3-0.5 tons per ton of lithium carbonate;

[0019] The carbonization stage is operated at room temperature, which saves 20%-30% energy compared with the traditional high-temperature and high-alkali process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is a schematic structural diagram of a lithium-containing wastewater treatment system according to the present invention;

[0022] Figure 2 This is a schematic diagram of the main cross-sectional structure of a lithium-containing wastewater treatment system of the present invention;

[0023] Figure 3 This is a schematic structural diagram of a reaction liquid discharge mechanism, a mixing mechanism, and a spiral annular gas injection mechanism in a lithium-containing wastewater treatment system of the present invention;

[0024] Figure 4This is a schematic structural diagram from a bottom perspective of a reaction liquid discharge mechanism, a mixing mechanism, and a spiral annular gas injection mechanism in a lithium-containing wastewater treatment system of the present invention;

[0025] Figure 5 This is an enlarged structural schematic diagram of a spiral annular gas injection mechanism in a lithium-containing wastewater treatment system of the present invention;

[0026] Figure 6 This is a partially enlarged structural schematic diagram of a reaction liquid discharge mechanism in a lithium-containing wastewater treatment system of the present invention;

[0027] Figure 7 This is a schematic diagram of the expanded structure of a reaction liquid discharge mechanism in a lithium-containing wastewater treatment system of the present invention;

[0028] Figure 8 This is a partially enlarged structural schematic diagram of a slot in a lithium-containing wastewater treatment system of the present invention;

[0029] Figure 9 This is a schematic structural diagram of a stirring component in a lithium-containing wastewater treatment system of the present invention.

[0030] The symbols in the accompanying drawings are described as follows: reaction liquid discharge mechanism 2; mixing mechanism 3; spiral annular cutting gas injection mechanism 4; stirring kettle 10; support frame 11; top cover 12; liquid infusion tube 13; servo motor 14; drainage pipe 15; gas injection pipe 16; main shaft 17; first liquid loading part 20; liquid control frame 21; double-ring drive part 22; connecting rod 23; leakage hole 24; drainage ball 25; slot 26; center tube 30; outer ring fixing ring 31; stirring part 32; guide slide rod 33; counterweight part 34; connecting part 35; slide plate part 36; gas chamber body 40; gas outlet nozzle 41; elastic spiral guide plate 42; connecting collar part 44. DETAILED DESCRIPTION

[0031] The present invention will now be further described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection of the present invention. These drawings are all simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic way, and therefore only show the structures related to the present invention.

[0032] To facilitate understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are shown 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.

[0033] All features disclosed in this specification, or all steps in the disclosed methods or processes, except mutually exclusive features and / or steps, can be combined in any manner.

[0034] Any feature disclosed in this specification (including any appended claims, abstract, and drawings), unless otherwise stated, may be replaced by other equivalent or similar features. In other words, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0035] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connected," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; they can refer to mechanical connection, direct connection, or indirect connection through an intermediate medium; they can refer to internal communication between at least two elements or interaction between at least two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0036] The following combination Figures 1-9 The present invention is described in detail. For the convenience of description, the directions mentioned below are defined as follows: the up, down, left, right, front and back directions mentioned below are the same as Figure 2 The front, back, left, right, up and down directions of the view are consistent. Figure 2 It is a front view of the device of the present invention, Figure 2 The directions shown are consistent with the front, back, left, right, up and down directions of the device of the present invention when viewed from the front.

[0037] See also Figures 1-9 The present invention provides an embodiment in which the main pollutants in lithium-containing wastewater are lithium ions and other coexisting ions (such as Na + , K + , Ca 2+ Mg 2+), organic matter, suspended solids, etc. In the treatment process of lithium-containing wastewater, pretreatment is first required to remove impurities, and then selectively enrich lithium ions to form a high-concentration lithium solution. To form lithium carbonate crystals, saturated sodium carbonate solution needs to be added. Lithium carbonate is used to manufacture the positive electrode material of lithium-ion batteries, such as lithium cobalt oxide, nickel-cobalt-manganese ternary materials, and nickel-cobalt-aluminum ternary materials. 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 production of lithium carbonate using sodium carbonate solution, we found that when stirring at low speed, the sodium carbonate solution is prone to local overconcentration in the lithium ion-enriched solution, triggering rapid nucleation, forming microcrystals or impurity co-precipitation. When stirring at high speed, the sodium carbonate solution can be quickly dispersed, avoiding local oversaturation that leads to excessive crystal nuclei and the formation of fine particles. These phenomena will have a serious impact on the production of lithium carbonate. Therefore, a lithium-containing wastewater treatment system is used to introduce carbon dioxide into the bottom of the lithium ion-enriched solution and add saturated sodium carbonate solution to the top to achieve dual synergistic production of lithium carbonate.

[0038] refer to Figure 1 and Figure 2, specifically including a stirring tank 10, a reaction liquid discharge mechanism 2, a mixing mechanism 3 and a spiral circumferential cutting gas injection mechanism 4, a top cover 12 is installed at the top opening position of the stirring tank 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 the main shaft 17, the servo motor 14 serves as the main power output for mixing and stirring, the reaction liquid discharge 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 discharge mechanism 2 is installed at the top, the spiral circumferential cutting gas injection mechanism 4 is installed at the bottom, the mixing mechanism 3 is installed between the reaction liquid discharge mechanism 2 and the spiral annular cutting gas injection mechanism 4, the enriched lithium ion solution to be treated is introduced into the inner cavity of the stirring tank 10, and the saturated sodium carbonate solution is added from the surface of the lithium ion solution as the reaction liquid, and the spiral annular cutting gas injection mechanism 4 at the bottom uses carbon dioxide as the reaction gas and injects it into the lithium ion solution along the annular cutting direction. When the mixing speed is slow, the annular cutting angle of carbon dioxide injected from the bottom is small, which ensures the residence time of carbon dioxide in the lithium ion solution. When the mixing speed is low, the top The amount of sodium carbonate solution added is also small, so the reaction of carbon dioxide is mainly based on the reaction of carbon dioxide, and the reaction of sodium carbonate solution is auxiliary. In the process of 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 also effectively inhibit the precipitation of CaCO3 and MgCO3, and rely on the CO2 carbonization path to generate LiHCO3. The subsequent thermal decomposition into Li2CO3 will also produce carbon dioxide. The carbon dioxide produced by thermal decomposition will join the reaction when the speed of mixing and stirring is accelerated in the later stage. When the mixing speed is increased in the later stage, the sodium carbonate solution added to the top reaction liquid discharge mechanism 2 also increases with the acceleration of the speed. At this time, the annular cutting angle of carbon dioxide injection in the spiral annular cutting gas injection mechanism 4 at the bottom becomes larger with the faster speed, reducing the residence time of carbon dioxide in the lithium ion solution, thereby forming a situation in which sodium carbonate solution is mainly used and carbon dioxide reaction is auxiliary. The rapid rise of carbon dioxide bubbles is used to further promote mass transfer and inhibit impurities from being adsorbed on the crystal surface, which greatly accelerates the reaction efficiency, improves unit production capacity, and obtains uniformly distributed large-sized lithium carbonate crystals, which is convenient for subsequent filtration and washing.

[0039] refer to Figure 3 、 Figure 7 、 Figure 8 and Figure 9It is worth mentioning that in this embodiment, the reaction liquid discharge mechanism 2 includes a first liquid-containing part 20, the top cover 12 is installed on the top of the first liquid-containing part 20, and the bottom of the first liquid-containing part 20 is distributed and penetrated with a plurality of leakage holes 24. A drainage ball 25 is installed in each leakage hole 24 in a rolling manner. The saturated sodium carbonate reaction liquid undergoing reaction is in the inner cavity of the first liquid-containing part 20. The sodium carbonate solution is brought to the bottom position of the first liquid-containing part 20 by the rolling of the drainage ball 25, and then falls. In order to further ensure the falling of the solution, a slot 26 is provided on the drainage ball 25. During the rolling circulation of the drainage ball 25, the slot 26 will collect the solution when it is located in the sodium carbonate solution and roll. When it reaches the bottom, the sodium carbonate solution will be put into the solution enriched with lithium ions due to the action of centrifugal force and gravity, and a liquid control frame 21 is fixedly installed on the main shaft 17, and a connecting rod 23 is distributed on the lower end surface of the liquid control frame 21. A double-ring driving member 22 is fixedly installed on the bottom of the connecting rod 23. The double-ring driving member 22 is tightly abutted against the outer end surface of the drainage ball 25. The rotation of the double-ring driving member 22 drives the drainage ball 25 to flip, and the slot 26 flips to the bottom to realize the falling of the reaction liquid. When the stirring speed is faster, the rolling and flipping speed of the drainage ball 25 is also faster, so that the falling speed of the reaction liquid is also faster, so that a sufficient amount of reaction liquid can be matched at the same time as the stirring speed.

[0040] refer to Figure 3 、 Figure 4 and Figure 5It is also worth mentioning that in this embodiment, the spiral annular 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, and the bottom of the stirring kettle 10 is installed with a gas injection pipe 16, which extends upward through the air cavity of the gas storage body 40 to provide a sufficient amount of carbon dioxide reaction gas for the reaction, and a number of gas outlet nozzles 41 and elastic spiral guide plates 42 are evenly distributed on the outer end surface of the gas storage body 40, and a connecting ring member 44 is slidably connected to the main shaft 17, and the outer end surface of the connecting ring member 44 is connected to each of the elastic spiral guide plates The inner end surfaces of the tops of the gas chambers 42 are fixedly connected, the gas outlet nozzle 41 and the internal air cavity of the gas chamber body 40 are communicated with each other, the gas outlet of the gas outlet nozzle 41 is directed toward the elastic spiral guide plate 42, so that the 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 annular 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 annular cutting gas injection mechanism 4, so as to realize the angle of the reaction gas adapted to be injected into the target at different rotation speeds, and utilizes the rotation speed to dynamically adjust and control the coordinated cooperation between the reaction liquid and the reaction gas.

[0041] refer to Figure 3 、 Figure 4 and Figure 9 It should be noted that, in this embodiment, the mixing mechanism 3 includes a central tube 30 and an outer fixing ring 31. The bottom and top ends of the central tube 30 are respectively provided with connecting parts. A number of stirring members 32 are equidistantly connected between the connecting parts and the outer fixing ring 31, so that the stirring members 32 are inclined at both the upper and lower positions, which can fully mix and stir and accelerate the reaction.

[0042] refer to Figure 3 、 Figure 4 and Figure 5It should also be noted that, in this embodiment, the angle adjustment assembly includes a guide slide 33 fixedly mounted between the center tube 30 and the outer ring fixing ring 31, a counterweight 34 is slidably connected to the guide slide 33, a slide plate 36 is slidably connected to the connecting portion at the bottom end of the center tube 30, a connecting member 35 is connected between the hinged portion of the slide plate 36 and the counterweight 34, and the bottom end of the slide plate 36 is fixedly mounted on the upper end surface of the connecting collar 44. When the speed of mixing becomes faster, the counterweight 34 is slidably connected to the guide slide 33 due to the centrifugal force. It will slide outward along the guide slide bar 33, thereby pulling the slide plate 36 to slide upward, so that the elastic spiral guide plate 42 is lifted up. After the elastic spiral guide plate 42 is lifted up, the inclination angle of the entire end becomes larger, thereby increasing the annular cutting angle of carbon dioxide injection, allowing carbon dioxide to quickly pass through the lithium ion solution, reducing the residence time in the solution, and thus being discharged from the top outlet pipe for recycling. Since the elastic spiral guide plate 42 itself is elastic, it will reset when the speed decreases.

[0043] refer to Figure 9 In order to further disperse the carbon dioxide gas to improve its contact with the lithium ion solution, in this embodiment, the stirring member 32 includes a mixing and stirring portion on the upper side and a bubble dispersing portion on the lower side. The mixing and stirring portion is a columnar structure with a fan-shaped cross section, and the bubble dispersing portion is an interwoven mesh plate structure. The mesh plate structure is located just above the injection of carbon dioxide gas. During the mixing and stirring process, the stirring member 32 rotates and uses the mesh to disperse the carbon dioxide to ensure the reaction surface of the carbon dioxide.

[0044] In addition, in one embodiment, a top cover 12 is installed on the upper end surface of the first liquid-containing part 20, and a liquid infusion tube 13 is installed on the upper end of the top cover 12. The bottom of the liquid infusion tube 13 passes through the inner cavity of the first liquid-containing part 20, and the reaction liquid is replenished through the liquid infusion tube 13.

[0045] Specific runtime:

[0046] Initial parameters and preparation phase

[0047] raw material:

[0048] Lithium-containing wastewater: Li + Concentration 12 g / L, containing Na + 3 g / L, Ca 2+ 50 mg / L, suspended solids 200 mg / L;

[0049] After pretreatment: a large amount of Ca is removed through precipitation, filtration, and ion exchange 2+ Mg 2+ , Li +The concentration was increased to 18 g / L and the pH was adjusted to 3.0 (acidic leachate);

[0050] The volume of the stirred tank 10 is 2000 L;

[0051] The initial stirring speed was controlled at 50 rpm (low speed stage), the temperature was controlled at 25 °C (normal temperature), and carbonization was dominant;

[0052] The CO2 flow rate is 0.8 L / min. It enters the gas chamber 40 through the gas injection pipe 16 and is injected into the solution along the guide plate through the gas outlet nozzle 41. At this time, due to the low rotation speed, the inclination angle of the elastic spiral guide plate 42 is about 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:

[0053] ;

[0054] The pH value rises from the initial 3.0 to 6.5, and is still in a weakly acidic environment. At the same time, the reaction liquid discharge mechanism 2 at the top adds a saturated sodium carbonate solution. The discharge ball 25 rolls at a speed of about 5 rpm, and the amount of sodium carbonate solution added is 0.6 times the theoretical value (about 1.8 L / h). The mesh bubble breaking part of the stirring member 32 cuts and breaks up the CO2 bubbles, increasing the gas-liquid contact area, and mixing and stirring at the same time, making the lithium ion solution gradually turbid, generating LiHCO3 intermediates. Due to the weakly acidic environment, Ca 2+ It is not easy to precipitate and inhibits the formation of CaCO3.

[0055] When the LiHCO3 concentration reaches 15 g / L through online conductivity monitoring, the system automatically increases the speed to 300 rpm, enters the later stage of high-speed mixing and stirring, and switches to precipitation-dominated mode;

[0056] At this time, the rolling speed of the drainage ball 25 is increased to 15 rpm, and the dosage of the 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 34 to move outward due to centrifugal force, pulling the slide 36 upward, and the inclination angle of the elastic spiral guide plate 42 increases to about 45°;

[0057] The CO2 flow rate was adjusted to 2.5 L / min, and the bubble rise time was shortened to 1 minute, which greatly reduced the residence time of carbon dioxide in the solution. At the same time, the heating system was started, and the solution temperature rose from 25°C to 95°C. Due to the increase in the amount of sodium carbonate added, the pH in the solution rose to 10.5, and the reaction path switched to:

[0058] ;

[0059] The carbon dioxide produced by pyrolysis is collected through the top exhaust pipe, and the unreacted CO2 is returned to the gas tank body 40 after condensation and drying. During the mixing and stirring process, the fan-shaped mixing and stirring part generates strong shear force to evenly disperse the sodium carbonate and prevent local oversaturation. When the solution transmittance is detected to be greater than 95%, it indicates that the precipitation is complete, so the stirring is stopped, the discharge valve at the bottom is opened, and the solution is discharged through the discharge pipe 15, and finally filtered and washed.

[0060] In the early stage of the mixing reaction, since there are still a certain amount of calcium ions and magnesium ions in the lithium ion solution, the carbonization of carbon dioxide is the dominant reaction in the early stage, which improves the lithium selectivity and reduces the co-precipitation of impurities. Under low-speed stirring, the residence time of carbon dioxide in the solution is prolonged, 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 easy to precipitate under acidic to neutral conditions. Therefore, the carbonization stage can give priority to fixing Li + , avoid premature co-precipitation of impurities, and effectively reduce the introduction of sodium ions,

[0061] In the later stage, high-speed stirring is switched to sodium carbonate and precipitation as the main method, supplemented by carbon dioxide synergistic effect. 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%). The assistance of carbon dioxide prevents the pH from being too high (>12) to cause Al 3+ 、SiO3 2- Impurities are precipitated and the reaction system is maintained in the optimal range of pH 10-11, which promotes each other with the initial low-speed stirring and accurately avoids the precipitation window of CaCO3 and MgCO3, thereby greatly reducing the precipitation of impurities mixed into the lithium carbonate precipitation. Moreover, CO2 bubbles rise rapidly under high-speed stirring to form turbulence, promote solution mixing, prevent crystal sedimentation or agglomeration, and take away tiny crystal nuclei to inhibit secondary nucleation. The CO2 microenvironment can adjust the crystal surface energy and guide lithium carbonate to grow along specific crystal planes to form regular rhombus or flaky crystals (SEM observation results), thereby improving the product processing performance and making the lithium carbonate crystals have large particle distribution.

[0062] Compared with traditional lithium carbonate production, the initial carbonization effectively reduces the loss of lithium ions in lithium ion recovery, thereby increasing the lithium ion recovery rate by 5% and significantly improving the product purity.

[0063] The above description is merely a specific embodiment of the invention, but the scope of protection of the invention is not limited thereto. Any changes or substitutions that are not conceived through creative effort should be included within the scope of protection of the invention. Therefore, the scope of protection of the invention should be based on the scope of protection defined in the claims.

Claims

1. A lithium-containing wastewater treatment system, characterized in that: The invention comprises a reaction liquid discharge mechanism (2), a mixing mechanism (3) and a spiral annular cutting gas injection mechanism (4), wherein the reaction liquid discharge mechanism (2) comprises a first liquid-containing part (20) and a liquid control component, wherein a plurality of liquid leakage holes (24) are distributed and penetrated at the bottom of the first liquid-containing part (20), and a liquid discharge ball (25) is installed in each of the liquid leakage holes (24) in a rolling manner, and the liquid control component drives the liquid discharge ball (25) to flip so as to adapt the speed of the reaction liquid falling into the target object according to the rotation speed, and the spiral annular cutting gas injection mechanism (4) comprises a gas chamber body (40) and a connecting member. The outer end surface of the gas chamber body (40) is evenly distributed with a plurality of gas outlet nozzles (41) and elastic spiral guide plates (42). The outer end surface of the connecting collar (44) is fixedly connected to the inner end surface of the top of each elastic spiral guide plate (42). The gas outlet nozzles (41) and the internal air cavity of the gas chamber body (40) are communicated with each other. The gas outlet of the gas outlet nozzles (41) faces the elastic spiral guide plate (42). The mixing mechanism (3) includes a central tube (30) and an outer ring fixed to the central tube (30). The center tube (30) is provided with a connecting portion at the bottom and top, respectively, and a plurality of stirring members (32) are connected to the outer ring fixing ring (31) at equal intervals. An angle adjustment assembly is provided between the mixing mechanism (3) and the spiral ring cutting and gas injection mechanism (4), and the angle adjustment assembly includes a guide slide (33) fixedly installed between the center tube (30) and the outer ring fixing ring (31), and a counterweight (34) is slidably connected to the guide slide (33). The connecting portion at the bottom of the center tube (30) is provided with a plurality of stirring members (32) at equal intervals. A slide member (36) is slidably connected to the connecting portion, a connecting member (35) is connected between the hinged portion of the slide member (36) and the counterweight member (34), and the bottom end of the slide member (36) is fixedly mounted on the upper end surface of the connecting collar member (44). The angle adjustment component adjusts the tilt angle of the elastic spiral guide plate (42) in real time according to the rotation speed of the spiral ring cutting gas injection mechanism (4), so as to achieve the angle at which the reaction gas is adapted to be injected into the target at different rotation speeds, and utilizes the rotation speed to dynamically adjust and control the coordinated cooperation between the reaction liquid and the reaction gas.

2. A lithium-containing wastewater treatment system according to claim 1, characterized in that: The liquid control assembly comprises a liquid control frame (21), a connecting rod (23) is distributedly installed on the lower end surface of the liquid control frame (21), a double-ring driving member (22) is fixedly installed on the bottom of the connecting rod (23), the double-ring driving member (22) is tightly abutted against the outer end surface of the liquid drainage ball (25), a slot hole (26) is opened on the top of the liquid drainage ball (25), and the rotation of the double-ring driving member (22) drives the liquid drainage ball (25) to flip, so that the slot hole (26) flips to the bottom to realize the falling of the reaction liquid.

3. A lithium-containing wastewater treatment system according to claim 2, characterized in that: The stirring member (32) comprises a mixing and stirring portion on the upper side and a bubble breaking portion on the lower side.

4. A lithium-containing wastewater treatment system according to claim 3, characterized in that: The mixing and stirring part is a columnar structure with a fan-shaped cross section, the bubble breaking part is an interwoven mesh plate structure, and the bubble breaking part is fixed on the mixing and stirring part.

5. A lithium-containing wastewater treatment system according to claim 4, characterized in that: The upper end surface of the first liquid-containing part (20) is provided with a top cover (12), the upper end of the top cover (12) is provided with a liquid replenishing tube (13), the bottom of the liquid replenishing tube (13) passes through and enters the inner cavity of the first liquid-containing part (20), and the reaction liquid is replenished through the liquid replenishing tube (13).

6. A lithium-containing wastewater treatment system according to claim 5, characterized in that: It also includes a stirring kettle (10), wherein a gas injection pipe (16) is installed at the bottom of the stirring kettle (10), and the gas injection pipe (16) extends upward and passes through the interior of the gas cavity of the gas chamber body (40).

7. A lithium-containing wastewater treatment system according to claim 6, characterized in that: A servo motor (14) is fixedly mounted on the upper end surface of the top cover (12), an 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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