A lithium precipitation mother liquor acidification device

Abstract

The utility model relates to lithium carbonate production technical field, concretely relates to a lithium precipitation mother liquor acidification device, through setting up the circulation pipeline that is communicated by circulation export, circulating pump, circulation pipe and circulation inlet forms makes the mixed mother liquor that is not fully reacted in acidification cavity refluxes again to acidification cavity through circulation pipeline, and then makes the mixed mother liquor that flows through circulation inlet such as more fully reacts, through setting up the PH meter in circulation loop close to circulation inlet one end real -time monitoring the PH value of mixed mother liquor that flows through the place more fully reacts after, improves the PH value measurement precision of mixed mother liquor after acidification treatment, and then according to the measured PH value of mixed mother liquor after acidification treatment more accurate control and regulation the flow of concentrated acid that adds in acidification cavity. In addition, improve the acidity and alkalinity measurement precision of mixed mother liquor after acidification treatment also can more accurate control and regulation the alkali amount in subsequent neutralization process, guarantee the acidity and alkalinity of neutralization mother liquor in the evaporation concentrated acid process time to meet the requirements, improve the recovery quality of lithium precipitation mother liquor.

Description

Technical Field

[0001] This utility model relates to the field of lithium carbonate production technology, specifically to an acidification device for lithium precipitation mother liquor. Background Technology

[0002] In the process of preparing lithium carbonate using sodium carbonate and lithium sulfate as the main reactants for lithium precipitation, a large amount of sodium sulfate solution, i.e., lithium precipitation mother liquor, is generated. This mother liquor contains a large amount of sulfate, sodium ions, carbonate ions, and unreacted lithium ions, therefore, it needs to be recovered. There are two conventional methods for recovering lithium precipitation mother liquor: one is evaporation and concentration, where the supernatant is recovered for slurry preparation and the condensate is used for sodium carbonate preparation; the other is secondary lithium precipitation. This invention mainly uses evaporation and concentration to recover the lithium precipitation mother liquor. To avoid carbonate formation during evaporation and concentration, which can lead to scaling in the evaporator and affect evaporation efficiency, concentrated sulfuric acid is added before evaporation to break down the carbonate ions. Concentrated sulfuric acid is usually added in excess to ensure complete removal of carbonate ions. To prevent the acidified lithium precipitation mother liquor from becoming highly acidic and corroding equipment after evaporation and concentration, alkali is added before evaporation to adjust its pH to 7-8.

[0003] Existing lithium precipitation mother liquor acidification equipment includes an acidification tank and a pH meter installed at the outlet of the acidification tank. The pH meter, or acid-base meter, is used to monitor the pH value of the acidified lithium precipitation mother liquor flowing through the outlet of the acidification tank. Based on the pH value monitored by the pH meter, the amount of acid added is adjusted to ensure that the pH value of the acidified lithium precipitation mother liquor is below 4, and the amount of alkali added in the subsequent neutralization process is adjusted to ensure that the pH value of the mother liquor at the evaporation potential is 7-8. Therefore, the measurement of the pH value of the acidified lithium precipitation mother liquor is particularly important. While the above methods can adjust the pH of the lithium precipitation mother liquor after acidification, in actual production, due to cost considerations, the volume of the acidification tank is generally 30-60 m³, resulting in a small acidification reaction space. This leads to a short residence time of the lithium precipitation mother liquor and concentrated acid solution in the acidification reactor. The lithium precipitation mother liquor flows out of the acidification tank outlet before the acidification reaction is fully completed. Consequently, the pH data measured by the pH meter at the outlet is not the pH value after the lithium precipitation mother liquor is fully acidified, and cannot accurately reflect the pH of the lithium precipitation mother liquor. This, in turn, leads to inaccurate control of the amount of acid added during the acidification reaction. Fluctuations in the amount of acid added will also lead to fluctuations in the amount of alkali added during the subsequent mother liquor neutralization process, resulting in unstable pH of the lithium precipitation mother liquor after the concentrated acid is evaporated, thus affecting the quality of lithium precipitation mother liquor recovery. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide an acidification device for lithium precipitation mother liquor, thereby improving the control accuracy of the pH of the lithium precipitation mother liquor after acidification.

[0005] The technical solution adopted by this utility model to solve its technical problem is: a lithium precipitation mother liquor acidification device, including an acidification tank with an acidification chamber, an acid injection port and a mother liquor inlet connected to the acidification chamber at the upper part of the acidification tank, and a drain port connected to the acidification chamber at the lower part of the acidification tank; it also includes a circulation pipe, a circulation pump and a pH meter;

[0006] The acidification tank is also provided with a circulation outlet and a circulation inlet connected to the acidification chamber. The circulation outlet is located at the lower part of the acidification tank, and the circulation inlet is located at the upper part of the acidification tank. The inlet of the circulation pump is connected to the circulation outlet, the outlet of the circulation pump is connected to the inlet of the circulation pipe, and the outlet of the circulation pipe is connected to the circulation inlet.

[0007] The pH meter has a monitoring end and an output end, and the monitoring end of the pH meter is located at one end of the circulation tube near the circulation inlet.

[0008] Furthermore, it also includes a drive motor disposed at the top of the acidification tank, a stirring shaft connected to the drive shaft of the drive motor, and stirring blades fixedly connected to the outer wall of the stirring shaft; the stirring shaft and the stirring blades are both disposed in the acidification chamber, and the stirring shaft is rotatably connected to the acidification tank;

[0009] The stirring blades are provided in multiple quantities, and the multiple stirring blades are evenly distributed along the circumference of the stirring shaft.

[0010] Furthermore, the mother liquor inlet, acid injection port, and circulation inlet are all located on the top wall of the acidification tank, while the drain port and circulation outlet are located on the lower part of the side wall of the acidification tank.

[0011] Furthermore, the inlet of the circulation pipe is connected to the circulation outlet, the inlet of the circulation pump is connected to the outlet of the circulation pipe, and the outlet of the circulation pump is connected to the circulation inlet.

[0012] Furthermore, it also includes a delivery pump and a drain pipe, wherein the inlet of the delivery pump is connected to the drain outlet, and the inlet of the drain pipe is connected to the outlet of the delivery pump.

[0013] Furthermore, it also includes a mother liquor delivery pipe, an acid injection pipe, a first flow meter, a second flow meter, and a flow control valve;

[0014] The outlet of the mother liquor delivery pipe is connected to the mother liquor inlet, and the outlet of the acid injection pipe is connected to the acid injection port; the first flow meter is installed on the mother liquor delivery pipe, and the second flow meter and the flow control valve are both installed on the acid injection pipe;

[0015] The first flow meter is used to monitor the flow rate of the mother liquor delivery pipe, the second flow meter is used to monitor the flow rate of the acid injection pipe, and the flow control valve is used to adjust the flow rate of the acid injection pipe.

[0016] Furthermore, it also includes the controller;

[0017] The output terminal of the pH meter, the first flow meter, the second flow meter, and the flow control valve are all electrically connected to the controller.

[0018] Furthermore, the top wall of the acidification tank is provided with a liquid inlet that communicates with the acidification chamber, and the mother liquor inlet and the acid injection port are the same liquid inlet; a liquid inlet pipe is connected to the liquid inlet, and the outlets of the mother liquor delivery pipe and the acid injection pipe are both connected to the liquid inlet of the liquid inlet pipe.

[0019] Compared with existing technologies, the beneficial effects of this utility model are as follows: It provides a lithium precipitation mother liquor acidification device. By setting up a circulation pipeline connecting a circulation outlet, a circulation pump, a circulation pipe, and a circulation inlet, the unreacted mixed mother liquor in the acidification chamber is returned to the acidification chamber via the circulation pipeline, thereby allowing the mixed mother liquor flowing through the circulation inlet to react more fully. By placing a pH meter at one end of the circulation loop near the circulation inlet to monitor the pH value of the more fully reacted mixed mother liquor in real time, the accuracy of pH value measurement of the mixed mother liquor after acidification is improved. This allows for more precise control of the flow rate of concentrated acid added to the acidification chamber based on the measured pH value of the mixed mother liquor after acidification. Furthermore, increasing the pH of the mixed mother liquor after acidification also allows for more precise control of the amount of alkali added in the subsequent neutralization process, ensuring that the pH of the neutralized mother liquor meets the requirements during the concentrated acid evaporation process, thus improving the recovery quality of the lithium precipitation mother liquor. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of this utility model;

[0021] Figure reference numerals: 1-Acidification tank; 10-Acidification chamber; 11-Acid injection port; 12-Mother liquor inlet; 13-Drain port; 14-Circulation outlet; 15-Circulation inlet; 2-Circulation pipe; 3-Circulation pump; 4-pH meter; 5-Stirring mechanism; 51-Drive motor; 52-Rotating shaft; 53-Stirring blade; 61-Mother liquor delivery pipe; 62-Acid injection pipe; 63-Inlet pipe; 64-Transfer pump; 65-Drain pipe; 71-First flow meter; 72-Second flow meter; 73-Flow control valve; 8-Controller. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0023] like Figure 1 As shown, a lithium precipitation mother liquor acidification device includes an acidification tank 1 with an acidification chamber 10. The upper part of the acidification tank 1 is provided with an acid injection port 11 and a mother liquor inlet 12 connected to the acidification chamber 10, and the lower part of the acidification tank 1 is provided with a drain port 13 connected to the acidification chamber 10. It also includes a circulation pipe 2, a circulation pump 3, and a pH meter 4. The acidification tank 1 is also provided with a circulation outlet 14 and a circulation inlet 15 connected to the acidification chamber 10. The circulation outlet 14 is located at the lower part of the acidification tank 1, and the circulation inlet 15 is located at the upper part of the acidification tank 1. The inlet of the circulation pump 3 is connected to the circulation outlet 14, the outlet of the circulation pump 3 is connected to the inlet of the circulation pipe 2, and the outlet of the circulation pipe 2 is connected to the circulation inlet 15. The pH meter 4 has a monitoring end and an output end. The monitoring end of the pH meter 4 is located in the circulation pipe 2 near the circulation inlet 15.

[0024] Lithium precipitation mother liquor is injected into the acidification chamber 10 of acidification tank 1 through mother liquor inlet 12, and concentrated sulfuric acid is injected into the acidification chamber 10 through acid injection port 11. The lithium precipitation mother liquor and concentrated sulfuric acid are mixed in the acidification chamber 10 to form a mixed mother liquor. The circulation pump 3 is started so that a small part of the mixed mother liquor in the acidification chamber 10 flows back to the acidification chamber 10 through the circulation pipeline formed by the circulation outlet 14, circulation pump 3, circulation pipe 2 and circulation inlet 15. Most of the mixed mother liquor in the acidification chamber 10 is discharged from the drain port 13 to the neutralization device to neutralize with the alkali solution. Because the acidification chamber 10 is relatively small, the lithium precipitation mother liquor and concentrated sulfuric acid have a short reaction time in the acidification chamber 10. The mixed mother liquor in the acidification chamber 10 may have to be discharged before it has fully reacted. However, the mixed liquor needs a certain amount of time to flow back to the circulation inlet 15 through the circulation pipeline. This provides more sufficient reaction time for the mixed mother liquor. That is, the mixed mother liquor that flows back to the circulation inlet 15 reacts more fully. Therefore, the pH meter 4 of this invention is set at one end of the circulation loop near the circulation inlet 1 to monitor the pH value of the mixed mother liquor flowing through that point in real time. This is the pH value of the mixed mother liquor after more complete reaction, which improves the pH measurement accuracy of the mixed mother liquor after acidification. Furthermore, based on the measured pH value of the mixed mother liquor after acidification, the flow rate of concentrated acid added to the acidification chamber 10 can be more accurately controlled to ensure that the carbonic acid in the mixed mother liquor is completely destroyed. In addition, improving the accuracy of pH measurement of the mixed mother liquor after acidification treatment can more precisely control the amount of alkali added in the subsequent neutralization process, ensuring that the pH of the neutralization mother liquor during the concentrated acid evaporation process meets the requirements, and improving the recovery quality of the lithium precipitation mother liquor. The concentration of concentrated sulfuric acid is generally 98%.

[0025] The acidification tank 1 is mainly used to contain concentrated sulfuric acid and lithium precipitation mother liquor and provide reaction space for their reaction. Preferably, it also includes a drive motor 51 located at the top of the acidification tank 1, a stirring shaft 52 connected to the drive shaft of the drive motor 51, and stirring blades 53 fixedly connected to the outer wall of the stirring shaft 52; the stirring shaft 52 and the stirring blades 53 are both located within the acidification chamber 10, and the stirring shaft 52 is rotatably connected to the acidification tank 1; multiple stirring blades 53 are provided, and the multiple stirring blades 53 are evenly distributed along the circumference of the stirring shaft 52. Generally, the stirring shaft 52 is arranged in the vertical direction, and the drive motor 51 is located at the upper end of the stirring shaft 52. The stirring blades have various structural forms, such as anchor-type stirring blades, spiral stirring blades, curved blade disc turbine-type stirring blades, ribbon-type stirring blades, etc. The stirring blades are generally welded or bolted to the stirring shaft 52. During the acidification of lithium precipitation mother liquor, the drive motor 51 drives the stirring shaft 52 to rotate relative to the acidification tank 1. The stirring shaft 52 drives the stirring blade 53 to rotate synchronously, stirring the sulfuric acid and lithium precipitation mother liquor in the acidification chamber 10 evenly, improving the reaction efficiency and degree of reaction of the two in the acidification chamber 10, thereby making the reaction of the mixed mother liquor flowing through the circulation pipeline near the circulation inlet 15 more complete, and further improving the accuracy of the pH value measured by the pH meter 4 at that location.

[0026] The mother liquor inlet 12 is used to inject lithium precipitation mother liquor into the acidification chamber 10, and the acid injection port 11 is used to inject concentrated sulfuric acid into the acidification chamber 10. The mother liquor inlet 12 and the acid injection port 11 can be located on the side wall or the top wall of the acidification tank 1, requiring that the liquid level in the acidification chamber 10 be lower than the height of the mother liquor inlet 12 and the acid injection port 11. The drain port 13 is used to discharge the mixed mother liquor in the acidification chamber 10 to the neutralization device in the next process, and the circulation outlet 14 is used to discharge the mixed mother liquor in the acidification chamber 10 into the circulation pipeline for sufficient reaction. The drain port 13 and the circulation outlet 14 are generally located at the bottom of the side wall of the acidification tank 1, which facilitates pipeline installation and also facilitates the discharge of the mixed mother liquor. The circulation inlet 15 is used to return the more fully reacted mixed mother liquor in the circulation pipeline to the acidification chamber 10. Its height displacement should be higher than the liquid level in the acidification chamber 10, and it can be located on the top wall or upper side wall of the acidification tank 1. Preferably, the mother liquor inlet 12, acid injection port 11, and circulation inlet 15 are all located on the top wall of the acidification tank 1, and the drain port 13 and circulation outlet 14 are all located on the lower part of the side wall of the acidification tank 1. This avoids the backflow of lithium precipitation mother liquor and concentrated sulfuric acid due to a high liquid level in the acidification chamber 10, ensuring that the mixed mother liquor at the bottom of the acidification chamber 10 is smoothly discharged into the circulation pipeline for full reaction and pH monitoring before smoothly flowing back to the upper part of the acidification chamber 10.

[0027] Specifically, it also includes a transfer pump 64 and a drain pipe 65. The inlet of the transfer pump 64 is connected to the drain port 13, and the inlet of the drain pipe 65 is connected to the outlet of the transfer pump 64. The transfer pump 64 is used to extract the mixed mother liquor from the acidification chamber 10, and the drain pipe 65 is used to transport the mixed mother liquor extracted by the transfer pump 64 to the subsequent neutralization device for neutralization reaction.

[0028] The circulation pipe 2 is the main structure of the circulation pipeline, connecting the circulation outlet 14 and the circulation inlet 15. The circulation pump 3 mainly provides driving force for the mixed mother liquor to flow back from the lower part of the acidification chamber 10 to the upper part of the acidification chamber 10 via the circulation pipeline. The pH meter 4 is used to continuously monitor the pH value of the mixed mother liquor flowing through the circulation pipeline near the circulation inlet 15 in real time. In addition to the above arrangement, as another embodiment, the inlet of the circulation pipe 2 is connected to the circulation outlet 14, the inlet of the circulation pump 3 is connected to the outlet of the circulation pipe 2, and the outlet of the circulation pump 3 is connected to the circulation inlet 15. That is, the mixed mother liquor in the acidification chamber 10 flows back into the acidification chamber 10 through the circulation pipeline formed by the circulation outlet 14, circulation pipe 2, circulation pump 3, and circulation inlet 15.

[0029] Generally, the mother liquor inlet 12 is connected to a mother liquor delivery pipe 61, which in turn connects to the lithium precipitation reaction device. The acid injection port 11 is connected to an acid injection pipe 62, which in turn connects to the sulfuric acid storage tank. Preferably, the system also includes a mother liquor delivery pipe 61, an acid injection pipe 62, a first flow meter 71, a second flow meter 72, and a flow control valve 73. The outlet of the mother liquor delivery pipe 61 is connected to the mother liquor inlet, and the outlet of the acid injection pipe 62 is connected to the acid injection port 11. The first flow meter 71 is installed on the mother liquor delivery pipe 61, and the second flow meter 72 and the flow control valve 73 are both installed on the acid injection pipe 62. The first flow meter 71 is used to monitor the flow rate of the mother liquor delivery pipe 61, the second flow meter 72 is used to monitor the flow rate of the acid injection pipe 62, and the flow control valve 73 is used to adjust the flow rate of the acid injection pipe 62. The first flow meter 71 is used to monitor the flow rate of the lithium precipitation mother liquor injected into the acidification chamber 10 through the mother liquor delivery pipe 61, and the second flow meter 72 is used to monitor the flow rate of the lithium precipitation mother liquor injected into the acidification chamber 10 through the acid injection pipe 62. The flow control valve 73 is adjusted by combining the pH value measured by the pH meter 4 with the flow values ​​of the first flow meter 71 and the second flow meter 72, thereby realizing the flow regulation of the acid injection pipe 62 and ensuring that the pH value of the mixed mother liquor after acidification is within the preset range.

[0030] As a further preferred embodiment, a controller 8 is also included; the output terminal of the pH meter 4, the first flow meter 71, the second flow meter 72, and the flow control valve 73 are all electrically connected to the controller 8. The pH meter 4 transmits the monitored pH value to the controller 8 in real time, and the first flow meter 71 and the second flow meter 72 also transmit their monitored flow data to the controller 8 in real time. After analyzing and judging the returned pH value, the controller 8 automatically controls and adjusts the flow control valve 73 to regulate the flow of the acid injection pipe 62, thereby regulating the flow of sulfuric acid injected into the acidification chamber 10, until the pH value monitored by the pH meter 4 is less than 4. The controller 8 replaces manual analysis of the pH data of the pH meter 4 and automatically completes the flow regulation of sulfuric acid injected into the acidification chamber 10, saving manpower and improving the efficiency of sulfuric acid flow regulation. The flow control valve 73 can be a speed control valve. The controller 8 can be an industrial computer, a programmable logic controller (PLC), etc.

[0031] As a further preferred embodiment, the top wall of the acidification tank 1 is provided with an inlet connected to the acidification chamber 10, and the mother liquor inlet 12 and the acid injection port 11 are the same inlet. An inlet pipe 63 is connected to the inlet, and the outlets of the mother liquor delivery pipe 61 and the acid injection pipe 62 are both connected to the inlet of the inlet pipe 63. The lithium-precipitated mother liquor in the mother liquor delivery pipe 61 and the concentrated sulfuric acid in the acid injection pipe 62 must sequentially enter the acidification chamber 10 through the inlet pipe 63 and the inlet. That is, the lithium-precipitated mother liquor and concentrated sulfuric acid can begin to react in the inlet pipe 63 before entering the acidification chamber 10, and will react more fully after entering the acidification chamber 10. Therefore, the reaction of the mixed mother liquor in the circulation pipeline will be more complete, further improving the measurement accuracy of the pH meter 4.

[0032] The embodiments described herein are preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape, and principle of this utility model should be included within the scope of protection of this utility model.

Claims

1. A lithium precipitation mother liquor acidification device, comprising an acidification tank (1) having an acidification chamber (10), wherein the upper part of the acidification tank (1) is provided with an acid injection port (11) and a mother liquor inlet (12) communicating with the acidification chamber (10), and the lower part of the acidification tank (1) is provided with a drain port (13) communicating with the acidification chamber (10); characterized in that: It also includes a circulation pipe (2), a circulation pump (3), and a pH meter (4); The acidification tank (1) is also provided with a circulation outlet (14) and a circulation inlet (15) connected to the acidification chamber (10). The circulation outlet (14) is located at the lower part of the acidification tank (1), and the circulation inlet (15) is located at the upper part of the acidification tank (1). The inlet of the circulation pump (3) is connected to the circulation outlet (14), the outlet of the circulation pump (3) is connected to the inlet of the circulation pipe (2), and the outlet of the circulation pipe (2) is connected to the circulation inlet (15). The pH meter (4) has a monitoring end and an output end. The monitoring end of the pH meter (4) is located at one end of the circulation tube (2) near the circulation inlet (15).

2. The lithium precipitation mother liquor acidification device according to claim 1, characterized in that, It also includes a drive motor (51) disposed on the top of the acidification tank (1), a stirring shaft (52) connected to the drive shaft of the drive motor (51), and a stirring blade (53) fixedly connected to the outer wall of the stirring shaft (52); the stirring shaft (52) and the stirring blade (53) are both disposed in the acidification chamber (10), and the stirring shaft (52) is rotatably connected to the acidification tank (1); The stirring blades (53) are provided in multiple ways, and the multiple stirring blades (53) are evenly distributed along the circumference of the stirring shaft (52).

3. The lithium precipitation mother liquor acidification device according to claim 1, characterized in that, The mother liquor inlet (12), acid injection port (11) and circulation inlet (15) are all located on the top wall of the acidification tank (1), and the liquid outlet (13) and circulation outlet (14) are all located on the lower part of the side wall of the acidification tank (1).

4. The lithium precipitation mother liquor acidification device according to claim 1, characterized in that, The inlet of the circulation pipe (2) is connected to the circulation outlet (14), the inlet of the circulation pump (3) is connected to the outlet of the circulation pipe (2), and the outlet of the circulation pump (3) is connected to the circulation inlet (15).

5. The lithium precipitation mother liquor acidification device according to claim 1, characterized in that, It also includes a delivery pump (64) and a drain pipe (65), the inlet of the delivery pump (64) being connected to the drain port (13), and the inlet of the drain pipe (65) being connected to the outlet of the delivery pump (64).

6. The lithium precipitation mother liquor acidification apparatus according to any one of claims 1-5, characterized in that, It also includes a mother liquor delivery pipe (61), an acid injection pipe (62), a first flow meter (71), a second flow meter (72), and a flow control valve (73). The outlet of the mother liquor delivery pipe (61) is connected to the mother liquor inlet, and the outlet of the acid injection pipe (62) is connected to the acid injection port (11); the first flow meter (71) is installed on the mother liquor delivery pipe (61), and the second flow meter (72) and the flow control valve (73) are both installed on the acid injection pipe (62); The first flow meter (71) is used to monitor the flow rate of the mother liquor delivery pipe (61), the second flow meter (72) is used to monitor the flow rate of the acid injection pipe (62), and the flow control valve (73) is used to adjust the flow rate of the acid injection pipe (62).

7. The lithium precipitation mother liquor acidification device according to claim 6, characterized in that, It also includes the controller (8); The output end of the pH meter (4), the first flow meter (71), the second flow meter (72) and the flow control valve (73) are all electrically connected to the controller (8).

8. The lithium precipitation mother liquor acidification device according to claim 7, characterized in that, The top wall of the acidification tank (1) is provided with an inlet that communicates with the acidification chamber (10). The mother liquor inlet (12) and the acid injection port (11) are the same inlet. An inlet pipe (63) is connected to the inlet. The outlets of the mother liquor delivery pipe (61) and the acid injection pipe (62) are connected to the inlet of the inlet pipe (63).

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