A lithium sulfate and sodium carbonate liquid-liquid continuous lithium precipitation mixed reaction system

Abstract

The present application relates to lithium salt production equipment technical field, especially to a kind of lithium sulfate and sodium carbonate liquid-liquid continuous lithium precipitation mixed reaction system.The technical scheme thereof includes: lithium sulfate liquid supply unit and sodium carbonate liquid supply unit are connected with online metering control unit respectively, online metering control unit is communicated with continuous lithium precipitation reaction unit respectively, the outlet of continuous lithium precipitation reaction unit is communicated with continuous discharge unit, and continuous lithium precipitation reaction unit includes reactor shell, and reactor shell is equipped with first feed inlet, second feed inlet and discharge outlet, and first feed inlet and second feed inlet are communicated with online metering control unit respectively, and reactor shell inside is sequentially equipped with flow guide mixing component, shear dispersion component and continuous discharge component.The present application is realized by collaborative design, and continuous stable lithium precipitation reaction of lithium sulfate and sodium carbonate is realized, equipment scaling and blockage are effectively reduced, and production continuity, product yield and operation reliability are improved.

Description

Technical Field

[0001] This invention relates to the field of lithium salt production equipment technology, and in particular to a continuous liquid-liquid lithium precipitation mixing reaction system of lithium sulfate and sodium carbonate. Background Technology

[0002] Lithium carbonate is a crucial raw material for industries such as new energy batteries, ceramics, glass, and fine chemicals. Currently, the industrial production of lithium carbonate commonly employs a metathesis reaction between lithium sulfate solution and sodium carbonate solution. In traditional production processes, the two liquid raw materials are typically added in batches or mixed using ordinary stirring. Due to the simultaneous presence of high concentrations of sulfate and carbonate in the reaction system, localized supersaturation zones can easily form during the reaction. This causes the generated lithium carbonate crystals to preferentially adhere to the inner walls of the equipment, stirring components, and the discharge point, gradually forming scale. This leads to problems such as reduced reactor volume utilization, pipeline blockage, decreased heat transfer efficiency, and frequent equipment shutdowns for cleaning, affecting production continuity and product yield.

[0003] Furthermore, existing continuous lithium deposition equipment mostly employs a conventional stirring structure, resulting in insufficient mixing uniformity after the two liquid streams enter the reactor. This easily leads to localized concentration gradients within the reaction system, causing uneven lithium carbonate crystal particle size distribution and significant crystal agglomeration, which is detrimental to subsequent solid-liquid separation and stable product quality control. Simultaneously, existing equipment lacks effective anti-clogging measures for material conveying and discharge areas during the reaction process. As operating time increases, crystal accumulation and blockage easily occur at the discharge end, making it difficult to meet the requirements of continuous, long-cycle industrial production.

[0004] Therefore, providing a continuous lithium sulfate and sodium carbonate liquid-liquid lithium precipitation mixing reaction system that can achieve continuous and precise feeding of two liquids, rapid mixing reaction, reduced crystal adhesion, and stable continuous operation has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the background art by proposing a continuous liquid-liquid lithium precipitation mixing reaction system of lithium sulfate and sodium carbonate.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a continuous lithium sulfate and sodium carbonate liquid precipitation mixing reaction system, comprising a lithium sulfate supply unit, a sodium carbonate supply unit, an online metering and control unit, a continuous lithium precipitation reaction unit, and a continuous discharge unit; The lithium sulfate supply unit and the sodium carbonate supply unit are respectively connected to the online metering control unit, the online metering control unit is respectively connected to the continuous lithium precipitation reaction unit, and the outlet of the continuous lithium precipitation reaction unit is connected to the continuous discharge unit. The continuous lithium deposition reaction unit includes a reactor shell, which is provided with a first inlet, a second inlet and an outlet, and the first inlet and the second inlet are respectively connected to the online metering and control unit; The reactor shell is provided with a flow guiding and mixing component, a shearing and dispersing component and a continuous discharge component in sequence along the material flow direction. The flow guiding and mixing component is used to guide the lithium sulfate solution entering from the first inlet and the sodium carbonate solution entering from the second inlet to form a confluence and mix. The shearing and dispersing component is used to continuously shear and disperse the mixed material. The continuous discharge component is used to continuously transport the reaction slurry to the discharge port.

[0007] Furthermore, the lithium sulfate supply unit includes a lithium sulfate storage tank, a precision filter, a heat exchanger, and a first metering pump arranged in sequence. The precision filter is used to remove mechanical impurities from the lithium sulfate solution, and the heat exchanger is used to preheat the lithium sulfate solution before delivering it to the online metering control unit.

[0008] Furthermore, the sodium carbonate supply unit includes a sodium carbonate storage tank, a precision filter, a heat exchanger, and a second metering pump arranged in sequence. The precision filter is used to remove mechanical impurities from the sodium carbonate solution, and the heat exchanger is used to preheat the sodium carbonate solution before delivering it to the online metering control unit.

[0009] Furthermore, the online metering control unit includes a first mass flow meter and a second mass flow meter respectively installed on the lithium sulfate delivery pipeline and the sodium carbonate delivery pipeline. The first mass flow meter is configured in conjunction with a first metering pump, and the second mass flow meter is configured in conjunction with a second metering pump to detect the delivery flow of the two materials respectively and adjust the delivery volume of the corresponding metering pump. Downstream of the first mass flow meter and the second mass flow meter, and upstream of the continuous lithium deposition reaction unit, a first proportional regulating valve and a second proportional regulating valve are respectively provided. The first proportional regulating valve and the second proportional regulating valve are used to adjust the instantaneous flow of their respective pipelines according to the feedback signals of the first mass flow meter and the second mass flow meter, so that the two materials continuously and synchronously enter the continuous lithium deposition reaction unit.

[0010] Furthermore, the flow guiding and mixing assembly includes a spiral flow guiding component disposed within the reactor shell. The spiral flow guiding component extends spirally along the material flow direction to guide the two liquid flows entering the reactor to form a continuous swirling flow and complete the initial mixing.

[0011] Furthermore, the shearing dispersion assembly includes a rotating shaft rotatably disposed within the reactor shell and a plurality of shearing teeth fixedly disposed on the outer periphery of the rotating shaft and spaced apart along the axial direction, with adjacent shearing teeth staggered to form a continuous shearing channel.

[0012] Furthermore, the shearing and dispersing assembly also includes a guide wheel disposed on the outer periphery of the rotating shaft. The guide wheel is coaxially and linked with the shearing teeth, and the guide wheel is correspondingly disposed with the continuous discharge assembly.

[0013] Furthermore, the inner surface of the reactor shell in contact with the material is provided with a nano anti-fouling coating. The nano anti-fouling coating is formed on the surface of a 316L stainless steel substrate. The thickness of the nano anti-fouling coating is 50-100 μm, the surface roughness Ra≤0.2 μm, and it has low surface energy and acid and alkali corrosion resistance.

[0014] Furthermore, the continuous lithium deposition reaction unit is equipped with an online monitoring module, which includes a temperature detection component at the feed end, a pressure detection component inside the reactor, and a differential pressure detection component at the discharge end. The discharge end is also equipped with an ultrasonic anti-clogging component. The temperature detection component is signal-connected to the heat exchanger, and the differential pressure detection component is signal-connected to the ultrasonic anti-clogging component.

[0015] Furthermore, the nano anti-fouling coating covers the inner surface of the reactor shell that comes into contact with the material, and the material contact surfaces of the flow guiding mixing component, the shearing dispersion component, and the continuous discharge component are all made of FPK26 high-strength anti-sticking material.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: By setting up a lithium sulfate supply unit, a sodium carbonate supply unit, an online metering and control unit, a continuous lithium precipitation reaction unit, and a continuous discharge unit, the two liquid raw materials can be continuously and synchronously introduced into the continuous lithium precipitation reaction unit for reaction, which is beneficial to improve the uniformity of material mixing, reduce local oversaturation, and improve the stability of continuous production. This invention, by sequentially arranging a flow-guiding mixing component, a shearing dispersion component, and a continuous discharge component within a continuous lithium deposition reaction unit, enables the material to sequentially complete flow-guiding mixing, shearing dispersion, and continuous discharge, thereby reducing lithium carbonate crystal agglomeration and material retention, and improving the continuity and stability of the reaction process. This invention effectively reduces the adhesion of lithium carbonate crystals to the inner wall of the reactor by setting a nano anti-fouling coating on the inner surface of the reactor shell in contact with the material, and working in conjunction with the flow guiding and mixing component, the shearing and dispersing component and the continuous discharge component, thereby reducing equipment scaling and reducing equipment maintenance frequency. This invention, by setting up an online monitoring module, monitors the temperature, pressure, and discharge pressure difference in real time during the reaction process. Combined with an ultrasonic anti-clogging component, it helps to detect abnormal material flow in a timely manner, reduce discharge blockage, and improve the reliability of continuous system operation. The present invention has a reasonable structural layout and high integration, which can realize the continuous liquid-liquid mixing reaction of lithium sulfate and sodium carbonate. It is suitable for the continuous production process of lithium carbonate, which is conducive to improving product yield and production efficiency, and reducing equipment operation and maintenance costs. Attached Figure Description

[0017] Figure 1 This is a system block diagram of the present invention. Detailed Implementation

[0018] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] like Figure 1 As shown, the present invention proposes a continuous lithium precipitation reaction system for lithium sulfate and sodium carbonate, comprising a lithium sulfate supply unit, a sodium carbonate supply unit, an online metering and control unit, a continuous lithium precipitation reaction unit, and a continuous discharge unit.

[0020] The lithium sulfate supply unit and sodium carbonate supply unit are respectively connected to the online metering control unit, which is in turn connected to the continuous lithium precipitation reaction unit. The outlet of the continuous lithium precipitation reaction unit is connected to the continuous discharge unit. The continuous lithium precipitation reaction unit includes a reactor shell with a first inlet, a second inlet, and a discharge outlet. The first and second inlets are respectively connected to the online metering control unit. Inside the reactor shell, along the material flow direction, a flow guiding and mixing component, a shearing and dispersing component, and a continuous discharge component are arranged sequentially. The flow guiding and mixing component guides the lithium sulfate solution entering from the first inlet and the sodium carbonate solution entering from the second inlet to form a confluence and mix. The shearing and dispersing component continuously shears and disperses the mixed material. The continuous discharge component continuously conveys the reaction slurry to the discharge outlet. After the two phases come into contact in the reactor, they react to rapidly generate lithium carbonate crystals, which are then quickly discharged to the downstream process through the discharge outlet. This integrated structure design, which allows for simultaneous liquid-liquid mixing, fundamentally changes the drawbacks of traditional processes, such as batch addition of materials, uneven mixing, and the formation of localized oversaturation zones on the inner wall of the equipment. It enables the two reactants to come into contact and react the moment they enter the reactor, significantly increasing the reaction rate.

[0021] The lithium sulfate supply unit comprises a lithium sulfate storage tank, a precision filter, a heat exchanger, and a first metering pump, connected in sequence. In actual operation, the lithium sulfate solution obtained by acid leaching is introduced into the lithium sulfate storage tank and diluted with deionized water to a lithium concentration of 25–30 g / L. This concentration range ensures high reaction efficiency and production capacity while preventing excessively rapid crystal precipitation and localized agglomeration due to excessive concentration. The pH of the solution is then adjusted to 7.5–9.0 to create a weakly alkaline environment, which is beneficial for the subsequent carbonation reaction. After adjustment, the lithium sulfate solution is filtered through a precision filter (5 μm filtration accuracy) to remove residual mechanical impurities and insoluble particles from the acid leaching process. This prevents impurities from entering the reactor and becoming a substrate for heterogeneous nucleation of lithium carbonate crystals, thus avoiding scale formation induced by impurities and affecting the anti-scaling effect of the coating. The filtered clear liquid is then preheated to 60–75°C through a heat exchanger before being delivered to the online metering and control unit. This preheating temperature satisfies the heat input requirements of the reaction while avoiding excessively high temperatures that could cause lithium carbonate to precipitate prematurely in the pipeline.

[0022] The sodium carbonate supply unit comprises a sodium carbonate storage tank, a precision filter, a heat exchanger, and a second metering pump, connected in sequence. In actual operation, sodium carbonate powder is added to the sodium carbonate storage tank (dissolving tank), and a 20% (w / w) sodium carbonate solution is prepared using deionized water. This concentration ensures an effective supply of carbonate ions while maintaining the solution's fluidity and stability, preventing sodium carbonate from crystallizing and clogging the pipeline at low temperatures. The prepared sodium carbonate solution is then filtered through a precision filter (5μm filtration accuracy) to remove mechanical impurities and insoluble substances from the sodium carbonate raw material. After preheating to 55°C via the heat exchanger, it is delivered to the online metering control unit, with the excess sodium carbonate coefficient controlled at 1.10–1.20. The reason for controlling the excess sodium carbonate is that the presence of excess carbonate ions promotes a more complete lithium sulfate conversion reaction towards lithium carbonate formation, thereby effectively reducing the residual lithium ion content in the mother liquor and improving the overall recovery rate of lithium resources. Preheating the sodium carbonate solution to 55°C serves two purposes: firstly, it keeps the temperature difference between the sodium carbonate solution and the lithium sulfate solution within a reasonable range, preventing sudden temperature changes due to excessive temperature differences during mixing and thus ensuring uniform crystal growth; secondly, it prevents crystallization from occurring in the sodium carbonate solution before it enters the reactor due to excessively low temperatures.

[0023] The online metering control unit includes a first mass flow meter and a second mass flow meter, respectively installed on the lithium sulfate delivery pipeline and the sodium carbonate delivery pipeline. The first mass flow meter is configured in conjunction with a first metering pump, and the second mass flow meter is configured in conjunction with a second metering pump, to detect the delivery flow of the two materials respectively. The control system adjusts the delivery rate of the corresponding metering pump in real time. A first proportional regulating valve and a second proportional regulating valve are respectively installed downstream of the first and second mass flow meters and upstream of the continuous lithium precipitation reaction unit. The first and second proportional regulating valves are used to finely adjust the instantaneous flow rate of their respective pipelines based on the flow detection signals fed back by the first and second mass flow meters in real time.

[0024] Through this closed-loop linkage control method of mass flow meter and metering pump, combined with the rapid and accurate response of proportional control valve to instantaneous flow, the feed control accuracy of lithium sulfate solution and sodium carbonate solution can reach ≤0.1%. The molar ratio of the two materials is precisely controlled between 1:1.1 and 1:1.20, ensuring that carbonate ions are always in excess throughout the reaction process, thereby promoting complete reaction. The setting of proportional control valve makes flow regulation no longer solely dependent on the frequency adjustment of the metering pump itself, but forms a two-stage regulation mode of "coarse adjustment of metering pump + fine adjustment of proportional control valve". This significantly improves the response speed and steady-state accuracy of flow control. Even when there are pressure fluctuations or changes in pipeline resistance in the liquid supply unit, the proportional control valve can still act quickly based on the instantaneous feedback of the mass flow meter to stabilize the instantaneous flow near the set value, thereby ensuring the real-time synchronization and ratio accuracy of the feed rates of the two materials.

[0025] Precise metering control not only ensures the stability of the stoichiometric ratio of the reaction, but also provides a prerequisite for the stable achievement of product purity standards.

[0026] The core equipment of the continuous lithium deposition reactor is a coated anti-scaling reactor. The reactor shell is made of 316L stainless steel, a material with excellent resistance to acid and alkali corrosion, capable of withstanding long-term chemical erosion from lithium sulfate solution, sodium carbonate solution, and high-salt materials generated during the reaction. All internal surfaces of the reactor in contact with the materials are coated with a nano-anti-scaling coating. This coating is 50–100 μm thick, with a surface roughness Ra ≤ 0.2 μm, exhibiting low surface energy and resistance to acid and alkali corrosion. The low surface energy of the nano-anti-scaling coating significantly reduces the adhesion work of lithium carbonate crystals to its surface, making it difficult for crystals to adhere stably to the coating surface, thus fundamentally inhibiting heterogeneous nucleation and wall growth of lithium carbonate crystals. Simultaneously, the extremely low surface roughness (Ra ≤ 0.2 μm) eliminates microscopic protrusions and depressions on the coating surface, severing the physical anchor points for crystal mechanical adhesion, further enhancing the anti-scaling effect. Even when the reactor is in a highly supersaturated crystallization environment during long-term continuous operation, lithium carbonate crystals can only nucleate and grow homogeneously in the bulk solution phase, and will not form a solid scale layer on the inner wall of the reactor.

[0027] The internal flow-guiding mixing assembly of the reactor includes a spiral flow-guiding component disposed within the reactor shell. This spiral flow-guiding component extends spirally along the material flow direction to guide the two liquid streams entering the reactor to form a continuous swirling flow and complete the initial mixing. When the lithium sulfate solution and sodium carbonate solution enter the reactor from the first and second inlets, respectively, under the forced guidance of the spiral flow-guiding component, the two liquid streams rapidly form a high-speed rotating confluence. During the swirling process, the two phases are repeatedly folded, stretched, and interwoven, achieving efficient mass exchange and mixing. This spiral flow-guiding mixing method differs from the local mixing mode of traditional stirred tank reactors. It maintains effective mixing intensity along the entire axial length of the reactor, avoiding short-circuiting and dead zones, ensuring that the two materials reach a uniform mixing state before entering the shear dispersion zone.

[0028] The shearing and dispersing assembly includes a rotating shaft rotatably mounted inside the reactor shell and multiple axially spaced shearing teeth fixedly mounted on the outer periphery of the shaft. Adjacent shearing teeth are staggered to form a continuous shearing channel. The shaft rotates at high speed under the drive of a driving device, with an adjustable speed range of 1450–3000 r / min. During high-speed rotation, the staggered shearing teeth perform multi-stage, continuous cutting and dispersing of the initially mixed material. When the mixture flows through the channel between adjacent staggered shearing teeth, it is subjected to a strong shearing force field, effectively breaking up the already formed lithium carbonate crystal aggregates. Simultaneously, supersaturated micro-regions that may form in the reaction system due to localized concentration unevenness are rapidly eliminated, thus avoiding crystal agglomeration and uneven particle size distribution problems caused by localized nucleation. The shearing teeth are specially designed with strong cutting power, capable of forcibly breaking up any crystalline agglomerates that may form in the reaction system, allowing them to redisperse in the liquid phase to continue participating in the crystal growth process.

[0029] Specifically, the spiral guide plate in the flow-guiding mixing component and the staggered cutting teeth in the shearing dispersion component are both made of high-strength, anti-adhesion FPK26 material. FPK26 material has extremely high hardness and excellent anti-adhesion properties, making it difficult for lithium carbonate crystals in the material to form a firm adhesion layer on its surface. Even under long-term operation under high-speed rotation and strong shearing conditions, the surfaces of the guide plate and cutting teeth maintain a good smoothness and do not change their flow-guiding and shearing geometry due to crystal adhesion, thus ensuring the consistency of mixing and shearing effects during long-term reactor operation. The shearing dispersion component also includes guide wheels set on the outer periphery of the rotating shaft. The guide wheels are coaxially linked with the shearing teeth and correspond to the continuous discharge component. As the guide wheels rotate with the shaft, they generate axial thrust, continuously pushing the reacted and generated lithium carbonate slurry in the reactor towards the discharge port. This, combined with the continuous discharge component, achieves forced material output, avoiding the risk of slurry stagnation and accumulation at the reactor discharge end, thus preventing blockage. By combining the nano-anti-scaling coating on the inner wall of the reactor with the high-hardness anti-adhesion material of the high-speed rotating parts, a full-coverage anti-scaling protection system is formed inside the reactor, from the wall to the rotating parts, achieving continuous and stable operation without scaling throughout the entire reaction process.

[0030] During the reaction, two raw materials (lithium sulfate solution and sodium carbonate solution) simultaneously enter the coated anti-scaling reactor through the first and second inlets. The reactor is started at a speed of 1450–3000 r / min, achieving instantaneous inflow and outflow under conditions of 85–95℃ and 0.3–0.6 MPa. The reaction temperature is controlled within the range of 85–95℃. This temperature range provides sufficient activation energy to promote rapid carbonation and also allows the generated lithium carbonate crystals to have suitable crystal growth kinetics, which is beneficial for obtaining lithium carbonate products with complete crystal shape and uniform particle size. The reaction pressure is maintained at 0.3–0.6 MPa. The moderately high-pressure environment helps to suppress the escape of carbon dioxide from the reaction system, ensuring the effective concentration of carbonate ions in the liquid phase, thereby ensuring that the carbonation reaction can be fully completed. The continuous flow reaction mode of "in and out" results in an extremely short average residence time and uniform distribution of materials in the reactor. Once the lithium carbonate crystals generated by the reaction reach the discharge end, they are quickly discharged by the continuous discharge component, avoiding excessive growth or secondary agglomeration of crystals due to prolonged residence in the reactor.

[0031] The continuous lithium deposition reaction unit is also equipped with an online monitoring module, which includes a temperature detection component at the feed end, a pressure detection component inside the reactor, and a differential pressure detection component at the discharge end. An ultrasonic anti-clogging component is also installed at the discharge end. The temperature detection component is connected to the heat exchanger; a temperature probe at the reactor inlet monitors the feed temperature in real time and feeds the temperature signal back to the control system. The control system automatically adjusts the heating power of the front-end heat exchanger according to a preset temperature range (70–80°C) to ensure that the temperature of the material entering the reactor remains stable within the process requirements. The pressure detection component monitors the internal pressure of the reactor in real time. When the pressure inside the reactor exceeds the control range of 0.3–0.6 MPa, the control system automatically adjusts the feed rate or the opening of the exhaust valve to bring the reaction pressure back to the set range. The differential pressure detection component is connected to the ultrasonic anti-clogging component. A differential pressure sensor at the discharge port monitors changes in the pressure difference across the discharge end to determine the material flow status. When the differential pressure increases to a preset threshold, it indicates potential slight stagnation or localized accumulation at the discharge end. At this point, the control system automatically activates the ultrasonic anti-clogging device, using high-frequency ultrasonic vibration to disperse and peel away the material adhering to or accumulated at the discharge port, restoring unobstructed discharge and effectively preventing blockages. Real-time data feedback from the reactor's temperature and pressure sensors allows the control system to automatically adjust the feed rate and reaction parameters, ensuring the entire reaction process remains within the optimal process window and guaranteeing long-term stable production.

[0032] The system also includes a centralized control cabinet, which serves as the central hub for signal collection and command issuance for the entire system. It is electrically and communicatively connected to the aforementioned process equipment and online monitoring modules via signal cables.

[0033] The above system is used for continuous liquid-liquid lithium precipitation reaction of lithium sulfate and sodium carbonate. Due to the anti-scaling properties of the coating and the cutting and guiding design, the equipment can operate continuously for 30 to 60 days without shutdown for cleaning. Even if maintenance is required after long-term operation, operators only need to rinse the inside of the reactor with deionized water. With the low surface energy self-cleaning function of the coating itself, the small amount of floating powder adhering to the wall can be easily washed away without mechanical scraping or chemical cleaning, which greatly reduces the operation and maintenance costs and labor intensity. The product yield after processing by this system can reach over 95%, and the product purity is stable between 99.2% and 99.5%. The lithium solid-liquid ratio can reach 1:6 to 1:9, indicating that the solid lithium carbonate has excellent settling performance during the reaction, which is conducive to the efficient implementation of subsequent solid-liquid separation processes. The residual lithium content in the lithium precipitation mother liquor is lower than 1.6 to 4.8 g / L, indicating that the lithium resources are fully recovered and utilized with a low loss rate. The sodium sulfate concentration in the mother liquor is lower than 210 g / L, and the salt content of the system is less than 21%, with the composition of the mother liquor within a relatively ideal range, creating favorable conditions for the subsequent recovery or discharge treatment of sodium sulfate in the mother liquor. This application ensures accurate raw material ratio and rapid mixing through the "liquid-liquid online mixing" design, with strong controllability of reaction parameters. The anti-scaling coating technology and the high-hardness anti-adhesion rotating components work synergistically to effectively solve the scaling and clogging problem caused by the sulfate and carbonate system in the traditional lithium sulfate to lithium carbonate conversion process, significantly improving production continuity and product yield, and providing an efficient, stable, and long-cycle technical solution for the industrial production of lithium carbonate from lithium sulfate.

[0034] The above specific embodiments are merely several further embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

[0035] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A continuous liquid-liquid lithium precipitation mixing reaction system using lithium sulfate and sodium carbonate, characterized in that, It includes a lithium sulfate supply unit, a sodium carbonate supply unit, an online metering and control unit, a continuous lithium precipitation reaction unit, and a continuous discharge unit; The lithium sulfate supply unit and the sodium carbonate supply unit are respectively connected to the online metering control unit, the online metering control unit is respectively connected to the continuous lithium precipitation reaction unit, and the outlet of the continuous lithium precipitation reaction unit is connected to the continuous discharge unit. The continuous lithium deposition reaction unit includes a reactor shell, which is provided with a first inlet, a second inlet and an outlet, and the first inlet and the second inlet are respectively connected to the online metering and control unit; The reactor shell is provided with a flow guiding and mixing component, a shearing and dispersing component and a continuous discharge component in sequence along the material flow direction. The flow guiding and mixing component is used to guide the lithium sulfate solution entering from the first inlet and the sodium carbonate solution entering from the second inlet to form a confluence and mix. The shearing and dispersing component is used to continuously shear and disperse the mixed material. The continuous discharge component is used to continuously transport the reaction slurry to the discharge port.

2. The lithium sulfate and sodium carbonate liquid-liquid continuous lithium precipitation mixing reaction system according to claim 1, characterized in that: The lithium sulfate supply unit includes a lithium sulfate storage tank, a precision filter, a heat exchanger, and a first metering pump arranged in sequence. The precision filter is used to remove mechanical impurities from the lithium sulfate solution, and the heat exchanger is used to preheat the lithium sulfate solution before delivering it to the online metering control unit.

3. The lithium sulfate and sodium carbonate liquid-liquid continuous lithium precipitation mixing reaction system according to claim 1, characterized in that: The sodium carbonate supply unit includes a sodium carbonate storage tank, a precision filter, a heat exchanger, and a second metering pump arranged in sequence. The precision filter is used to remove mechanical impurities from the sodium carbonate solution, and the heat exchanger is used to preheat the sodium carbonate solution before delivering it to the online metering control unit.

4. The lithium sulfate and sodium carbonate liquid-liquid continuous lithium precipitation mixing reaction system according to claim 1, characterized in that: The online metering control unit includes a first mass flow meter and a second mass flow meter respectively installed on the lithium sulfate delivery pipeline and the sodium carbonate delivery pipeline. The first mass flow meter is configured in conjunction with a first metering pump, and the second mass flow meter is configured in conjunction with a second metering pump to detect the delivery flow of the two materials respectively and adjust the delivery volume of the corresponding metering pump. Downstream of the first mass flow meter and the second mass flow meter, and upstream of the continuous lithium precipitation reaction unit, a first proportional regulating valve and a second proportional regulating valve are respectively provided. The first proportional regulating valve and the second proportional regulating valve are used to adjust the instantaneous flow of their respective pipelines according to the feedback signals of the first mass flow meter and the second mass flow meter, so that the two materials continuously and synchronously enter the continuous lithium precipitation reaction unit.

5. The lithium sulfate and sodium carbonate liquid-liquid continuous lithium precipitation mixing reaction system according to claim 1, characterized in that: The flow guiding and mixing assembly includes a spiral flow guiding component disposed within the reactor shell. The spiral flow guiding component extends spirally along the material flow direction to guide the two liquid flows entering the reactor to form a continuous swirling flow and complete the initial mixing.

6. The lithium sulfate and sodium carbonate liquid-liquid continuous lithium precipitation mixing reaction system according to claim 1, characterized in that: The shearing and dispersing assembly includes a rotating shaft rotatably disposed within the reactor shell and a plurality of shearing teeth fixedly disposed on the outer periphery of the rotating shaft and spaced apart along the axial direction, with adjacent shearing teeth arranged in a staggered manner to form a continuous shearing channel.

7. The lithium sulfate and sodium carbonate liquid-liquid continuous lithium precipitation mixing reaction system according to claim 6, characterized in that: The shearing and dispersing assembly further includes a guide wheel disposed on the outer periphery of the rotating shaft. The guide wheel is coaxially and linked with the shearing teeth, and the guide wheel is correspondingly disposed with the continuous discharge assembly.

8. The lithium sulfate and sodium carbonate liquid-liquid continuous lithium precipitation mixing reaction system according to claim 1, characterized in that: The inner surface of the reactor shell that comes into contact with the material is provided with a nano anti-fouling coating. The nano anti-fouling coating is formed on the surface of a 316L stainless steel substrate. The nano anti-fouling coating has a thickness of 50-100 μm, a surface roughness Ra≤0.2 μm, and has low surface energy and resistance to acid and alkali corrosion.

9. A continuous liquid-liquid lithium precipitation mixing reaction system for lithium sulfate and sodium carbonate according to any one of claims 1 to 3, characterized in that: The continuous lithium deposition reaction unit is equipped with an online monitoring module, which includes a temperature detection component at the feed end, a pressure detection component inside the reactor, and a differential pressure detection component at the discharge end. The discharge end is also equipped with an ultrasonic anti-clogging component. The temperature detection component is signal-connected to the heat exchanger, and the differential pressure detection component is signal-connected to the ultrasonic anti-clogging component.

10. The lithium sulfate and sodium carbonate liquid-liquid continuous lithium precipitation mixing reaction system according to claim 8, characterized in that: The nano anti-fouling coating covers the inner surface of the reactor shell that comes into contact with the material. The material contact surfaces of the flow guiding mixing component, the shearing dispersion component, and the continuous discharge component are all made of FPK26 high-strength anti-sticking material.

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