Lithium precipitation mother liquor recovery device

Abstract

The utility model discloses a lithium precipitation mother liquor recovery device, and belongs to the technical field of lithium salt recovery. Comprising an acidification pool used for acidifying lithium precipitation mother liquor flowing into the pool; the aging tank is used for carrying out aging treatment on the acidified lithium-containing solution; the ultrafiltration membrane is used for performing ultrafiltration treatment on the aged lithium-containing solution; an adsorption column of the adsorption system is filled with a lithium adsorbent, and the adsorption system is used for adsorbing and extracting lithium from the lithium-containing clear liquid obtained after ultrafiltration; the nanofiltration membrane is used for carrying out nanofiltration treatment on the desorption liquid obtained in the adsorption system; the concentration device is used for concentrating the nanofiltration water; the hardness removal reactor is used for removing hardness of the concentrated water after concentration; the boron removal resin bed is used for carrying out adsorption boron removal treatment on the hardness removal water phase; and the precipitation reaction kettle is used for adding a precipitator into the boron-removed produced water to generate lithium carbonate precipitate.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium salt recovery, in particular to a lithium precipitation mother liquor recovery device. Background Art

[0002] As the metal element with the lowest density in nature, lithium is widely used in many fields such as nuclear industry, new energy, new materials, and medicine due to its excellent properties. The level of lithium production affects the development of emerging industries to a certain extent and restricts the emergence of new technologies. In recent years, with the rapid development of the lithium battery industry, the development and extraction of lithium resources has gradually received attention. However, due to the solubility limitation of lithium carbonate, the single-pass yield of lithium precipitation is only about 80%, and about 20% of lithium ions remain in the lithium precipitation mother liquor and cannot be recovered to make lithium carbonate products.

[0003] The lithium precipitation mother liquor is Na + , Li + , CO 3 2- Mainly (Li + The content is about 1-2g / L, Na + The content is about 50-60g / L, the carbonate content is about 10-20g / L), and it also contains some B and Cl - 、SO 4 2- High-salinity alkaline brine system.

[0004] At present, the commonly used method for treating lithium immersion mother liquor in the industry is to first add sulfuric acid to neutralize carbonate, then evaporate and concentrate to separate sodium sulfate, and then return the mother liquor to the lithium leaching system. This traditional lithium immersion mother liquor recovery process has the following disadvantages: the sodium sulfate (or sodium chloride) solid separated by evaporation and concentration will carry lithium, causing lithium loss; the Na in the concentrated lithium immersion mother liquor is + , K + High concentration will further affect the purity of the prepared lithium carbonate product; the process repeatedly circulates the lithium precipitation mother liquor, the direct yield is low, the acid consumption is high, and the production cost is high.

[0005] In view of the shortcomings of the traditional method, the process was subsequently improved accordingly. The improved method is to first freeze the lithium mother liquor to precipitate sodium sulfate, then evaporate and concentrate lithium carbonate, and then freeze the mother liquor again and circulate the precipitation. However, the use of such traditional processes not only has high energy consumption, but also has a low lithium recovery rate.

[0006] Chinese patent CN 102249471 B proposes a method for treating battery-grade lithium carbonate mother liquor, wherein the lithium precipitation mother liquor is first acidified, sodium is precipitated to obtain a lithium chloride solution, and then lithium is precipitated again to obtain a lithium carbonate product. This method can improve the utilization rate of the lithium precipitation mother liquor, but the purity of the sodium carbonate obtained by the secondary precipitation is significantly different from that of the primary precipitation, and the purity of the lithium carbonate obtained by the secondary precipitation is not high.

[0007] Therefore, it is necessary to develop a new method for extracting lithium from lithium precipitation mother liquor, which can achieve high-quality lithium recovery with low energy consumption and controllable costs. Summary of the invention

[0008] The purpose of the utility model is to provide a lithium precipitation mother liquor recovery device to address the problems of long process, high power consumption, and high additional investment and construction costs of existing lithium precipitation mother liquor recovery technologies. The lithium precipitation mother liquor is first acidified, then ultrafiltration is performed to separate the lithium precipitation clear liquor, and finally the existing or newly built adsorption system is used to efficiently recover lithium.

[0009] The technical solution of the utility model is: a lithium precipitation mother liquor recovery device, comprising:

[0010] Acidification tank, used to acidify lithium precipitation mother liquor flowing into the tank, industrial hydrochloric acid flows into the tank from the bottom liquid inlet end;

[0011] An aging tank, connected to the acidification tank, for aging the acidified lithium-containing solution;

[0012] An ultrafiltration membrane, connected to the aging tank, for ultrafiltration treatment of the aged lithium-containing solution;

[0013] The adsorption system is connected to the ultrafiltration membrane, and the adsorption column is filled with a lithium adsorbent, which is used to adsorb and extract lithium from the lithium-containing clear liquid obtained after ultrafiltration;

[0014] A nanofiltration membrane is connected to the adsorption system and is used to perform nanofiltration treatment on the desorption liquid obtained in the adsorption system;

[0015] A concentration device, connected to the nanofiltration membrane, for concentrating the nanofiltration water;

[0016] A hardness removal reactor is connected to the concentration device and is used to remove hardness from concentrated concentrated water;

[0017] The boron removal resin bed is connected to the hardness removal reactor and is used for adsorption and boron removal treatment of the hardness removal water phase;

[0018] The precipitation reactor is connected to the boron removal resin bed and is used to add a precipitant to the produced water to generate lithium carbonate precipitation.

[0019] Furthermore, a stirring device is provided in the acidification tank to accelerate the acidification process, and the stirring speed is 100-600 rpm.

[0020] Furthermore, a water absorption tank is connected to the top of the acidification tank for recovering HCl gas generated during the acidification process by water absorption.

[0021] Preferably, the number of water absorption pools is set to three, and the three water absorption pools are connected in series.

[0022] Furthermore, a concentration detector is provided on the terminal liquid outlet pipe of the water absorption tank, the terminal liquid outlet pipe is connected to a three-way electronic valve, one liquid outlet of the three-way electronic valve is directly connected to the liquid inlet end at the top of the acidification tank through a pipeline, and the other liquid outlet end is connected to a concentrator, the liquid outlet of the concentrator is connected to the liquid inlet end at the top of the acidification tank, and a flow meter is provided at the liquid inlet end at the top of the acidification tank for controlling the inflow of the HCl recovery liquid.

[0023] As an alternative to the water absorption tank, the top outlet pipe of the acidification tank is connected to the condenser to condense and recover the HCl gas produced during the acidification process. The real-time concentration of the HCl solution after condensation is monitored by a concentration meter, and the concentration of the condensed solution is adjusted through an external water pipe. After reaching the concentration requirement, it is re-introduced into the acidification tank for acidification of the lithium precipitation mother liquor. A flow meter is provided at the top liquid inlet end of the acidification tank.

[0024] Furthermore, a filter is provided downstream of the precipitation reactor to separate the wet lithium carbonate generated after the precipitation reaction, and the filtrate merges with the lithium precipitation mother liquor and flows into the acidification tank again.

[0025] Furthermore, a slurry washing tank is provided downstream of the filter for slurry washing of wet lithium carbonate, and the slurry washing liquid merges with the lithium precipitation mother liquor and flows into the acidification tank again for treatment.

[0026] Furthermore, the washed lithium carbonate is placed in a drying oven for drying and then crushed by a crusher.

[0027] Furthermore, a flow meter is provided at the bottom liquid inlet end of the acidification tank for controlling the amount of industrial hydrochloric acid flowing into the tank.

[0028] The beneficial effects of the utility model are:

[0029] 1. The present application discloses a lithium precipitation mother liquor recovery device, which is designed for the lithium extraction process of lithium precipitation mother liquor, and proposes a scheme of first passing the lithium precipitation mother liquor into an acidification tank for acidification, which can consume the high-content carbonate and most of the bicarbonate in the solution and convert them into chloride ions, which can significantly improve the recovery rate of lithium in the lithium precipitation mother liquor;

[0030] 2. The adsorption system used in the lithium precipitation mother liquor recovery device disclosed in the present application is an existing aluminum-based lithium extraction adsorption system. After lithium extraction by adsorption, nanofiltration, concentration, hardness removal, and boron removal, lithium carbonate precipitation can be performed. The overall process is relatively simple, which solves the problems of long recovery technology process, high power consumption, and high additional investment and construction costs in the prior art;

[0031] 3. In the present application, the slurry washing liquid, filtrate and lithium precipitation mother liquor generated in the lithium extraction process are circulated into the adsorption section, thereby realizing the recovery of lithium, improving the total lithium recovery rate of the system, and recovering the water resources and energy generated in the system, which fully plays the role of reducing energy consumption, realizing the recycling of water resources and improving the lithium recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural diagram of the lithium extraction device for lithium precipitation mother liquor disclosed in this application;

[0033] Figure 2 For Figure 1 A structural diagram of a lithium extraction device for lithium precipitation mother liquor after adding a waste gas treatment device on the basis of the lithium precipitation mother liquor;

[0034] Figure 3 For Figure 1 The structural diagram of the lithium extraction device of lithium precipitation mother liquor after adding another waste gas treatment equipment on the basis of the above;

[0035] Among them, 1-acidification tank, 2-aging tank, 3-ultrafiltration membrane, 4-adsorption system, 5-nanofiltration membrane, 6-concentration device, 7-hardness removal reactor, 8-boron removal resin bed, 9-precipitation reactor, 10-filter, 11-slurry washing tank, 12-drying box, 13-pulverizer, 14-water absorption tank, 15-concentration detector, 16-three-way electronic valve, 17-concentrator, 18-flow meter, 19-condenser, 20-stirring device. DETAILED DESCRIPTION

[0036] The following examples further illustrate the content of the utility model, but should not be construed as limiting the utility model. Without departing from the essence of the utility model, modifications and replacements made to the methods, steps or conditions of the utility model are within the scope of the utility model.

[0037] The lithium precipitation mother liquor belongs to a high-salinity alkaline brine system, and its pH is generally between 8 and 11. The ion composition of the lithium precipitation mother liquor is complex, and the concentrations of various ions are Li + :1~2g / L,Na + :40~70g / L,K + :0~10g / L,Ca 2+ :0~100mg / L,Mg 2+: 0~100mg / L, B: 0~2000mg / L, Si: 0~100mg / L, Cl - :50~200g / L,SO 4 2- :0~40g / L,CO 3 2- :10~20g / L,HCO 3 - :0~10g / L,OH - : 0~5g / L.

[0038] Since the content of carbonate and bicarbonate in the lithium precipitation mother liquor is relatively high, the present application chooses to first pass the lithium precipitation mother liquor into an acidification tank for acidification, and industrial hydrochloric acid is passed into the acidification tank. The mass percentage of industrial hydrochloric acid is 20wt% to 36wt%. The amount of hydrochloric acid is determined according to the alkalinity content in the lithium precipitation mother liquor, wherein n(CO 3 2- ):n(HCl)=1:1-3、n(HCO 3 - ):n(HCl)=1:0.5-1.5、n(OH - ):n(HCl)=1:0.5-1.5, and then add them together to get the theoretical amount. The actual amount of industrial hydrochloric acid added is 0.8 to 1.3 times the theoretical value.

[0039] In order to speed up the acidification process, a stirring device is installed in the acidification tank to stir the mixed liquid at a speed of 100 to 600 rpm to accelerate the acidification process. Of course, the acidification tank can also be connected to a blower to accelerate the acidification process by continuously blowing air into the acidification tank. However, the process of accelerating the acidification by blowing air should be carried out when CO can be discharged. 2 In this case, the acidification tank should be connected to CO 2 Exhaust pipe, in CO 2 Set up CO in the exhaust pipe 2 Selective filtration membrane, air blowing rate should be theoretical CO 2 0.5 to 1.5 times the generation rate.

[0040] HCl gas will also be produced during the acidification process. If it is not treated accordingly, it will not only cause a waste of raw materials, but also cause waste gas pollution. Therefore, a condenser is connected to the acidification tank to condense and recover the HCl gas. The concentration of the HCl solution after condensation is monitored by a concentration meter. The concentration of the condensed solution can be adjusted through an external water pipe. After reaching the concentration requirement, it is re-introduced into the acidification tank for acidification of lithium precipitation mother liquor.

[0041] As another embodiment, the present application connects a three-stage water absorption tank to the acidification tank, and utilizes the water absorption method to perform three-stage series recovery of HCl gas. The recovered HCl solution can be directly introduced into the acidification tank for acidification of the lithium precipitation mother liquor. Alternatively, a concentrator can be provided between the three-stage water absorption tank and the acidification tank, and the recovered HCl solution is concentrated to meet the concentration requirement, and then reintroduced into the acidification tank for acidification of the lithium precipitation mother liquor.

[0042] After removing HCl gas, CO 2 It is collected for lithium carbonate carbonization related experiments or directly discharged.

[0043] The pH of the lithium-containing solution after acidification should reach 4 to 8, preferably 4 to 6. However, when there is a large amount of buffer system in the solution, the acidification process cannot make the pH of the lithium-containing solution reach 4 to 8, which will cause adsorbent poisoning. Therefore, the acidification tank is connected to the aging tank, and the acidified lithium precipitation mother liquor is aged for 0.5 to 3 hours. A pH detector is connected to the aging tank to monitor the pH change of the aging liquid online and control the reaction endpoint.

[0044] When the aging is completed, the lithium-containing solution should be relatively clear. At this time, the lithium-containing solution is passed into a filtering device for filtering to remove suspended particles in the solution. The filtering device used here may refer to an ultrafiltration membrane, and the filtering accuracy of the ultrafiltration membrane is controlled at 50,000-300,000 Da.

[0045] After being filtered by the filter device, the turbidity of the lithium-containing clear solution is low, generally 0-3 NTU. The concentration of various ions in the lithium-containing clear solution is generally Li + :1~2g / L,Na + :40~70g / L,K + :0~10g / L,Ca 2+ :0~100mg / L,Mg 2+ : 0~100mg / L, B: 0~2000mg / L, Si: 0~100mg / L, Cl - :50~200g / L,SO 4 2- :0~40g / L,HCO 3 - : 0~200mg / L.

[0046] The lithium-containing clear liquid is passed into the adsorption system for adsorption and lithium extraction. The adsorption system is a 20-column or 30-column ion exchange system. The lithium extraction agent loaded in the adsorption column is an aluminum-based lithium extraction agent. The packing density of the aluminum-based lithium extraction agent in a single adsorption column is 0.3-0.6 kg / L.

[0047] The qualified liquid desorbed from the adsorption system flows into the nanofiltration membrane, which is connected to the adsorption system to filter the desorbed liquid from the adsorption system. Its function is to intercept the divalent salt in the eluent and make Li + through.

[0048] After that, you can choose to continue concentrating the nanofiltration water. After removing the divalent ions during the nanofiltration process, continue to concentrate the permeate through reverse osmosis to further increase the ion concentration. The reverse osmosis concentrated water continues to flow through the hardness removal reactor for hardness removal. The reverse osmosis fresh water can return to the adsorption column analysis liquid for desorption of the lithium adsorbent.

[0049] The reverse osmosis concentrated water after hardness removal is treated by an adsorption boron removal system to obtain a boron-removed lithium-rich solution.

[0050] The boron-removed lithium-rich solution is sent to a lithium precipitation device to precipitate lithium, and the wet lithium carbonate and the mother liquor after lithium precipitation are obtained by filtration. The mother liquor after lithium precipitation is merged with the mother liquor after lithium precipitation, and the wet lithium carbonate is washed 2 to 5 times (the amount of water used for each washing is 1 to 3 times the mass of the wet lithium carbonate), dried, and crushed to obtain a lithium carbonate product, the purity of the lithium carbonate product is ≥99%. The slurry of the wet lithium carbonate is also merged with the mother liquor after lithium precipitation for cyclic treatment.

[0051] Example 1

[0052] Based on the above process, the device structure provided by the utility model is as follows Figure 1-2 As shown, including:

[0053] Acidification tank 1, industrial hydrochloric acid is filled into the tank from the bottom liquid inlet end to acidify the inflowing lithium precipitation mother liquor.

[0054] The stirring device 20 is arranged in the acidification tank 1 to accelerate the acidification process, and the stirring speed is 100-600 rpm.

[0055] The water absorption tank 14 is connected to the top of the acidification tank 1 and is used to recover the HCl gas generated in the acidification process by using a water absorption method.

[0056] In this embodiment, the number of the water absorption pools 14 is set to three, and the three water absorption pools are connected in series.

[0057] A concentration detector 15 is provided on the terminal liquid outlet pipe of the water absorption tank, and the terminal liquid outlet pipe is connected to a three-way electronic valve 16. One liquid outlet of the three-way electronic valve 16 is directly connected to the acidification tank 1 through a pipeline, and the other liquid outlet end is connected to a concentrator 17. The liquid outlet of the concentrator 17 is connected to the acidification tank 1. A flow meter 18 is provided at the top liquid inlet end of the acidification tank 1 for controlling the inflow of the HCl recovery liquid.

[0058] A flow meter 18 is also provided at the bottom liquid inlet end of the acidification tank 1 for controlling the amount of industrial hydrochloric acid flowing into the tank.

[0059] The aging tank 2 is connected to the acidification tank 1 and is used for aging the acidified lithium-containing solution.

[0060] The ultrafiltration membrane 3 is connected to the aging tank 2 and is used for ultrafiltration treatment of the aged lithium-containing solution.

[0061] The adsorption system 4 is a 30-column ion exchange system, in which the adsorption columns are filled with lithium adsorbents for adsorbing and extracting lithium from the lithium-containing clear solution obtained after ultrafiltration.

[0062] The nanofiltration membrane 5 is connected to the adsorption system 4 and is used for performing nanofiltration treatment on the desorption liquid obtained in the adsorption system.

[0063] The concentrator 6 is connected to the nanofiltration membrane 5. The concentrator 6 refers to a reverse osmosis membrane and is used to concentrate the nanofiltration water.

[0064] The hardness removal reactor 7 is connected to the concentration device 6 and is used to remove hardness from the reverse osmosis concentrated water.

[0065] The boron removal resin bed 8 is connected to the hardness removal reactor 7 and is used for adsorbing and removing boron from the hardness removal water phase.

[0066] The precipitation reactor 9 is connected to the boron removal resin bed 8 and is used to add a precipitant to the produced water to generate lithium carbonate precipitation.

[0067] The filter 10 is connected to the precipitation reactor 9 and is used to filter out the wet lithium carbonate. The filtrate and the lithium precipitation mother liquor merge and flow into the acidification tank 1 again for treatment.

[0068] The pulp washing tank 11 is connected to the filter 10 and is used for pulp washing wet lithium carbonate. The pulp washing liquid and the lithium precipitation mother liquor merge and flow into the acidification tank 1 again for treatment.

[0069] The drying box 12 is connected to the pulp washing tank 11 and is used for drying the washed lithium carbonate.

[0070] The pulverizer 13 is connected to the drying box 12 and is used to pulverize the dried lithium carbonate.

[0071] Example 2

[0072] refer to Figure 3 The difference between this embodiment and embodiment 1 is that, as an alternative, the acidification tank 1 is not connected to the water absorption tank 14, but is connected to a condenser 19 to condense and recover the HCl gas. The real-time concentration of the HCl solution after the condensation treatment is monitored by a concentration meter 15, and the concentration of the condensed solution can be adjusted through an external water pipe. After reaching the concentration requirement, it is re-introduced into the acidification tank 1 for acidification of the lithium precipitation mother liquor.

[0073] Application Example 1

[0074] 200L lithium precipitation mother liquor was recovered, and the composition of lithium precipitation mother liquor was Li + :1.6g / L、Na + :45g / L、Cl - :60g / L、CO 3 2- :13g / L、HCO 3 - :2g / L. Acidification was carried out at room temperature, and ultrasound was used to accelerate the reaction rate. The ultrasonic frequency was 30kHz, and the amount of 30wt% industrial hydrochloric acid added was 10L. Stirring and acidification was carried out for 1h, and aging was carried out for 0.5h to ensure sufficient reaction of the hydrochloric acid. After acidification, the pH of the lithium-containing solution was 6.5, and the volume was 210L. During the acidification process, HCl was recovered by water absorption. The water absorption recovery method was a three-stage series recovery. The solution after acidification was relatively clear. After acidification, the lithium-containing solution was passed through a 50nm ceramic membrane for solid-liquid separation. The volume of the obtained lithium-containing clear liquid was 200L, and the turbidity was 1NTU. The composition of the lithium-containing clear liquid is Li + :1.5g / L、Na + :43g / L、Cl - :57g / L、HCO 3 - :200mg / L. The lithium-containing clear liquid is used as the inlet water to enter the 30-column ion exchange adsorption system, and the aluminum-based lithium extracting agent is used to extract lithium. The rotation interval of the adsorption system is 10min, the lithium concentration of the tail water is 10-20mg / L, and the treatment rate is 0.65g / L / h; the lithium carbonate product is obtained by subsequent filtration, pulp washing, drying and crushing.

[0075] Application Example 2

[0076] Recycle 100L lithium precipitation mother liquor, which contains Li + :1.5g / L、Na + :50g / L, K + :10g / L、Ca 2+ :10mg / L、Mg 2+ : 10mg / L, B: 1000mg / L, Si: 50mg / L, Cl - :65g / L、SO 4 2- :10g / L、CO 3 2- :15g / L、HCO 3 -:3g / L. Acidification was carried out at room temperature, and stirring was used to accelerate the reaction rate. The stirring rate was 300rpm, and the amount of 30wt% industrial hydrochloric acid added was 6.5L. Stirring and acidification were carried out for 2h, and aging was carried out for 2h to ensure that the hydrochloric acid fully reacted. The pH of the lithium-containing solution after acidification was 5, and the volume was 106L. HCl vapor was condensed and recovered during the acidification process. The solution was turbid after acidification. The acidified lithium-containing solution was passed through a 50nm ceramic membrane for solid-liquid separation. The volume of the obtained lithium-containing clear liquid was 101L and the turbidity was 2NTU. The composition of the lithium-containing clear liquid is Li + :1.4g / L、Na + :47g / L, K + :9.3g / L、Ca 2+ :9mg / L、Mg 2+ : 9mg / L, B: 900mg / L, Si: 50mg / L, Cl - :60g / L、SO 4 2- : 9g / L, HCO 3 - :100mg / L. The lithium-containing clear liquid is used as the inlet water to enter the 30-column ion exchange adsorption system, and the aluminum-based lithium extracting agent is used to extract lithium. The rotation interval of the adsorption system is 10min, the lithium concentration of the tail water is 20-30mg / L, and the treatment rate is 0.6g / L / h; the lithium carbonate product is obtained by subsequent filtration, pulp washing, drying and crushing.

[0077] The above shows and describes the basic principles, main features and advantages of the utility model. However, the above is only a specific embodiment of the utility model, and the technical features of the utility model are not limited thereto. Any other implementation methods derived by any technician in the field without departing from the technical solution of the utility model should be included in the patent scope of the utility model.

Claims

1. A lithium precipitation mother liquor recovery device, characterized in that: include: Acidification tank, used to acidify lithium precipitation mother liquor flowing into the tank, industrial hydrochloric acid flows into the tank from the bottom liquid inlet end; An aging tank, connected to the acidification tank, for aging the acidified lithium-containing solution; An ultrafiltration membrane, connected to the aging tank, for ultrafiltration treatment of the aged lithium-containing solution; The adsorption system is connected to the ultrafiltration membrane, and the adsorption column is filled with a lithium adsorbent, which is used to adsorb and extract lithium from the lithium-containing clear liquid obtained after ultrafiltration; A nanofiltration membrane is connected to the adsorption system and is used to perform nanofiltration treatment on the desorption liquid obtained in the adsorption system; A concentration device, connected to the nanofiltration membrane, for concentrating the nanofiltration water; A hardness removal reactor is connected to the concentration device and is used to remove hardness from concentrated concentrated water; The boron removal resin bed is connected to the hardness removal reactor and is used for adsorption and boron removal treatment of the hardness removal water phase; The precipitation reactor is connected to the boron removal resin bed and is used to add a precipitant to the produced water to generate lithium carbonate precipitation.

2. A lithium precipitation mother liquor recovery device as claimed in claim 1, characterized in that: A stirring device is provided in the acidification tank to accelerate the acidification process, and the stirring speed is 100~600 rpm.

3. A lithium precipitation mother liquor recovery device as claimed in claim 1, characterized in that: The top of the acidification tank is connected to a water absorption tank for recovering the HCl gas generated in the acidification process by water absorption.

4. A lithium precipitation mother liquor recovery device as claimed in claim 3, characterized in that: The number of water absorption pools is set to three, and the three water absorption pools are connected in series.

5. A lithium precipitation mother liquor recovery device as claimed in claim 3, characterized in that: A concentration detector is provided on the terminal liquid outlet pipe of the water absorption tank, and the terminal liquid outlet pipe is connected to a three-way electronic valve, one liquid outlet of the three-way electronic valve is directly connected to the liquid inlet end at the top of the acidification tank through a pipeline, and the other liquid outlet end is connected to a concentrator, and the liquid outlet of the concentrator is connected to the liquid inlet end at the top of the acidification tank. A flow meter is provided at the liquid inlet end at the top of the acidification tank for controlling the inflow of the HCl recovery liquid.

6. A lithium precipitation mother liquor recovery device as claimed in claim 1, characterized in that: The gas outlet pipe at the top of the acidification tank is connected to the condenser, which is used to condense and recover the HCl gas generated during the acidification process. The real-time concentration of the HCl solution after condensation is monitored by a concentration meter, and the concentration of the condensed solution is adjusted through an external water pipe. After reaching the concentration requirement, it is re-introduced into the acidification tank for acidification of lithium precipitation mother liquor. A flow meter is provided at the top liquid inlet end of the acidification tank.

7. A lithium precipitation mother liquor recovery device as claimed in claim 1, characterized in that: A filter is provided downstream of the precipitation reactor to separate the wet lithium carbonate generated after the precipitation reaction. The filtrate merges with the lithium precipitation mother liquor and flows into the acidification tank again.

8. A lithium precipitation mother liquor recovery device as claimed in claim 7, characterized in that: A slurry washing tank is provided downstream of the filter for slurry washing of wet lithium carbonate. The slurry washing liquid merges with the lithium precipitation mother liquor and then flows into the acidification tank again for treatment.

9. A lithium precipitation mother liquor recovery device as claimed in claim 8, characterized in that: The washed lithium carbonate is placed in a drying oven for drying and then crushed by a crusher.

10. The lithium precipitation mother liquor recovery device according to claim 1, characterized in that: A flow meter is provided at the bottom liquid inlet of the acidification tank to control the amount of industrial hydrochloric acid flowing into the tank.

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