A device for recovering lithium carbonate from lithium extraction solution in salt lake

Abstract

The present application relates to the technical field of lithium extraction from salt lakes, and in particular to a device for recovering lithium carbonate from lithium extraction solutions from salt lakes, which includes a pretreatment device, an extraction phase separation tank, a storage tank, a pump group, a stripping phase separation tank, an oil removal device, a lithium precipitation crystallization device, a separation device and a drying device, which are connected in sequence through pipelines; the top of the stripping phase separation tank is connected to an extractant tank, the extractant tank is connected to the lithium solution inlet end of the extraction phase separation tank, and the bottom of the stripping phase separation tank is connected to the oil removal device; it also includes waste gas treatment equipment, cleaning equipment and wastewater collection equipment, a vent pipe is provided at the top of the extraction phase separation tank, and the waste gas treatment equipment is connected to the vent pipe; the cleaning equipment is respectively connected to the lithium solution inlet end of the extraction phase separation tank and the inlet end of the storage tank, and the bottom of the extraction phase separation tank and the stripping phase separation tank are both provided with a wastewater discharge pipe, and the wastewater discharge pipe is connected to the wastewater collection equipment. The present application has the effect of reducing environmental pollution and safety hazards.

Description

Technical Field

[0001] The present application relates to the technical field of lithium extraction from salt lakes, and in particular to a device for recovering lithium carbonate from lithium extraction solutions from salt lakes. Background Art

[0002] With the rapid development of the new energy industry, the demand for lithium has increased year by year, and lithium extraction and separation technology has also received more and more attention. my country's salt lake lithium resources are rich, but due to the high magnesium-lithium ratio and the difficulty of separation, they have not yet been effectively developed and utilized. The development of lithium extraction and separation technology suitable for my country's high magnesium-lithium ratio salt lake brine has important research value and strategic significance.

[0003] The main technologies for extracting lithium from salt lakes with high magnesium / lithium ratios include nanofiltration and electrodialysis, extraction and adsorption. Among them, the extraction method can extract lithium from brine with a high Mg / Li ratio, and can produce battery-grade lithium carbonate with a purity of up to 99.9%, with the advantages of short process, high efficiency and low consumption of raw materials. However, this process has high requirements for the corrosion resistance of the equipment. During the industrialization process, it is urgent to study the equipment structure, mass transfer and amplification. The risks brought by residual extractants to the subsequent processing of old brine magnesium resources in salt lakes should be taken seriously. The new extraction process using ion wave bodies as solvents and membrane extraction processes have certain advantages in environmental protection, but due to the short development time, less research and relatively high cost, there are no industrial application examples.

[0004] In addition, during the extraction operation, the organic solvent may form insoluble precipitates with water or other solvents, which may block the pipeline or reduce the accuracy of the experimental results; and the organic solvents used in the extraction operation are flammable, explosive and toxic, which will not only pollute the surrounding environment, but also pose serious safety hazards. Utility Model Content

[0005] In order to reduce environmental pollution and potential safety hazards, the present application provides a device for recovering lithium carbonate from a lithium extraction solution from a salt lake.

[0006] The present application provides a device for recovering lithium carbonate from a lithium extraction solution from a salt lake, which adopts the following technical solution:

[0007] A device for recovering lithium carbonate from a lithium extraction solution in a salt lake comprises a pretreatment device, an extraction phase separation tank, a storage tank, a pump group, a stripping phase separation tank, an oil removal device, a lithium precipitation crystallization device, a separation device and a drying device, wherein the pretreatment device, the extraction phase separation tank, the storage tank, the pump group, the stripping phase separation tank, the oil removal device, the lithium precipitation crystallization device, the separation device and the drying device are connected in sequence through pipelines; the top of the extraction phase separation tank is connected to the storage tank, and the bottom of the extraction phase separation tank is connected to an oil separator; the top of the stripping phase separation tank is connected to an extractant tank, the extractant tank is connected to a lithium solution inlet end of the extraction phase separation tank, and the bottom of the stripping phase separation tank is connected to the oil removal device; the device also comprises an exhaust gas treatment device, a cleaning device and a wastewater collection device, the top of the extraction phase separation tank is provided with an air venting pipe, and the exhaust gas treatment device is connected to the air venting pipe; the cleaning device is respectively connected to the lithium solution inlet end of the extraction phase separation tank and the inlet end of the storage tank, and the bottoms of the extraction phase separation tank and the stripping phase separation tank are both provided with wastewater discharge pipes, and the wastewater discharge pipes are connected to the wastewater collection device.

[0008] By adopting the above technical solution, since some dissolved gas will be released from the solution during the oscillation process, the gas pressure will increase, and the organic reagent is easy to volatilize, a vent pipe is set on the top of the extraction phase separation tank. The vent pipe is connected to the waste gas treatment equipment to treat the released gas, which not only prevents the occurrence of explosion accidents, but also reduces pollution to the surrounding environment.

[0009] In addition, cleaning equipment is installed at the lithium solution inlet of the extraction phase separation tank and the inlet of the storage tank to regularly clean the pipes and equipment to avoid the formation of sediment. The wastewater collection equipment can collect the wastewater generated by cleaning to reduce pollution to the environment and reduce many safety hazards.

[0010] Optionally, the exhaust gas treatment equipment includes a gas collector, a gas purifier and a gas recoverer, the gas collector is connected to the exhaust pipe, one end of the gas purifier is connected to the gas collector, and the other end is connected to the gas recoverer.

[0011] By adopting the above technical solution, the gas is collected and then purified by a gas purifier, and then the pure gas is collected by a gas collector for standby use, thereby realizing gas recycling and reducing the pollution of the surrounding environment by the gas generated by the extraction.

[0012] Optionally, a stirring mechanism is provided in both the extraction phase separation tank and the back extraction phase separation tank, a driving mechanism is provided on the top of both the extraction phase separation tank and the back extraction phase separation tank, the stirring mechanism is fixedly connected to the driving mechanism, and sieve holes are provided on the stirring mechanism.

[0013] By adopting the above technical scheme, a stirring mechanism is set in the extraction phase separation tank and the back extraction phase separation tank, and the driving mechanism drives the stirring mechanism to rotate to play a stirring role, which can not only make the two phases mixed evenly in the early stage, but also eliminate the "foam" at the interface caused by mild emulsification and promote stratification; and after the solution enters from the connecting pipe, it can freely penetrate from the sieve hole of the stirring mechanism, thereby reducing the impact caused by the stirring mechanism.

[0014] Optionally, the outlet end of the oil separator is connected to an adsorption tank, one end of the adsorption tank is connected to an extraction phase separation tank, and the other end of the adsorption tank is connected to a raffinate treatment device.

[0015] By adopting the above technical scheme, after the residual oil produced after the raffinate is isolated and extracted by the oil separator, the unextracted lithium ions in the raffinate are adsorbed by the adsorption tank, and then sent back to the extraction phase separation tank for re-extraction, so as to collect the residual lithium ions and reduce resource waste. The remaining raffinate is treated by the raffinate treatment equipment and then discharged to achieve environmentally friendly discharge standards.

[0016] Optionally, an alkali liquid tank is provided at the outlet end of the pretreatment equipment, and the alkali liquid tank is connected to a pipeline at the outlet end of the pretreatment equipment.

[0017] By adopting the above technical solution, the alkali liquid tank provides the required alkali for the extraction phase separation tank. The addition of alkali during the extraction process can neutralize the acidic substances, turning them into neutral or slightly alkaline conditions, thereby promoting the extraction of compounds; in addition, the addition of alkali can change the pH value of the extract, thereby increasing or decreasing the solubility of specific compounds and promoting the extraction of target compounds.

[0018] Optionally, a pressure regulating pump is provided at the outlet end of the cleaning equipment, and a water pump is provided on the wastewater discharge pipe.

[0019] By adopting the above technical solution, a pressure regulating pump is arranged at the outlet end of the cleaning equipment, which can increase or decrease the hydraulic pressure of the cleaning liquid, thereby realizing pressure washing of the extraction phase separation tank, the stripping phase separation tank, pipelines and other equipment; and a pumping pump is arranged on the wastewater discharge channel to extract the cleaning liquid in the extraction phase separation tank and the stripping phase separation tank and transport it to the wastewater collection equipment.

[0020] Optionally, flow meters are provided at the solution inlet ends of the extraction phase separation tank and the stripping phase separation tank.

[0021] By adopting the above technical solution, the flow meter can measure the flow rate in the pipeline at any time, and then adjust the addition rate of the solution at the inlet end of the extraction phase separation tank and the stripping phase separation tank, so that the solution enters the extraction phase separation tank and the stripping phase separation tank at an appropriate speed.

[0022] Optionally, both the extraction phase separation tank and the back extraction phase separation tank are provided with temperature controllers.

[0023] By adopting the above technical solution, the boiling point of the organic solvent used in the extraction operation is relatively high, so it is necessary to operate at a relatively high temperature. However, too high a temperature may cause the organic solvent to decompose or explode, so a temperature controller is provided to control the temperature in the tank within a certain range.

[0024] Optionally, observation windows are provided on the surfaces of the extraction phase separation tank and the back extraction phase separation tank along the vertical direction.

[0025] By adopting the above technical solution, observation windows are set on the surfaces of the extraction phase separation tank and the back extraction phase separation tank, so that the operator can observe the phase stratification in the tank with the naked eye at any time and make a favorable judgment.

[0026] In summary, the present application includes at least one of the following beneficial technical effects:

[0027] 1. By setting a vent pipe at the top of the extraction phase separation tank and connecting the vent pipe to the waste gas treatment equipment, the released gas can be treated, which not only prevents the occurrence of explosion accidents, but also reduces the pollution to the surrounding environment. In addition, cleaning equipment is set at the lithium solution inlet end of the extraction phase separation tank and the inlet end of the storage tank to regularly clean the pipeline and equipment to avoid the formation of sediments, and the wastewater collection equipment is set to collect the wastewater generated by cleaning to reduce pollution to the environment and reduce many safety hazards.

[0028] 2. By setting a stirring mechanism in the extraction phase separation tank and the back extraction phase separation tank, the driving mechanism drives the stirring mechanism to rotate to play a stirring role, which can not only make the two phases mixed evenly in the early stage, but also eliminate the "foam" at the interface caused by mild emulsification and promote stratification.

[0029] 3. By setting up an adsorption tank, when the raffinate is separated from the residual oil produced after extraction by the oil separator, the unextracted lithium ions in the raffinate are adsorbed by the adsorption tank, and then sent back to the extraction phase separation tank for re-extraction, so as to collect the residual lithium ions and reduce resource waste. The remaining raffinate is treated by the raffinate treatment equipment and then discharged to achieve environmentally friendly discharge standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of a device for recovering lithium carbonate from a lithium extraction solution from a salt lake in the present application.

[0031] Figure 2 It is a partial schematic diagram of a device for recovering lithium carbonate from a lithium extraction solution from a salt lake in the present application.

[0032] Explanation of the reference numerals: 1. pretreatment equipment; 2. extraction phase separation tank; 201. vent pipe; 3. storage tank; 4. pump group; 5. stripping phase separation tank; 6. oil removal equipment; 7. lithium precipitation crystallization equipment; 8. separation equipment; 9. drying equipment; 10. oil separator; 11. extractant tank; 12. waste gas treatment equipment; 121. gas collector; 122. gas purifier; 123. gas recovery device; 13. cleaning equipment; 14. waste water collection equipment; 15. stirring mechanism; 151. sieve hole; 16. driving mechanism; 17. adsorption tank; 18. raffinate treatment equipment; 19. alkali liquid tank; 20. pressure regulating pump; 21. water pump; 22. flow meter; 23. temperature controller; 24. observation window; 25. stripping agent tank; 26. tee. DETAILED DESCRIPTION

[0033] The following is combined with Figure 1-2 This application is described in further detail.

[0034] The present application embodiment discloses a device for recovering lithium carbonate from a lithium extraction solution from a salt lake. Figure 1 , a device for recovering lithium carbonate from a lithium extraction solution in a salt lake comprises a pretreatment device 1, an extraction phase separation tank 2, a storage tank 3, a pump group 4, a stripping phase separation tank 5, an oil removal device 6, a lithium precipitation crystallization device 7, a separation device 8 and a drying device 9, wherein the pretreatment device 1, the extraction phase separation tank 2, the storage tank 3, the pump group 4, the stripping phase separation tank 5, the oil removal device 6, the lithium precipitation crystallization device 7, the separation device 8 and the drying device 9 are sequentially connected by pipelines. The top outlet end of the extraction phase separation tank 2 is connected to the storage tank 3 through a pipeline, and the bottom outlet end of the extraction phase separation tank 2 is connected to the oil separator 10 through a pipeline; the phase loaded with the extractant at the top outlet end of the extraction phase separation tank 2 enters the storage tank 3 and is transported to the stripping phase separation tank 5 by the pump group 4. In addition, a stripping agent tank 25 is also provided on one side of the pump group 4, and the stripping agent tank 25 is connected to the pump group 4 through a pipeline, and the stripping agent is transported to the stripping phase separation tank 5 through the pump group 4. The top outlet of the stripping phase separation tank 5 is connected to the extractant tank 11, and the extractant tank 11 is connected to the lithium solution inlet of the extraction phase separation tank 2, and the unloaded extractant obtained after stripping is returned to the extraction phase separation tank 2 for recycling, and the bottom outlet of the stripping phase separation tank 5 is connected to the inlet of the oil removal device 6, and the outlet of the oil removal device 6 is connected to the inlet of the separation device 8, and the outlet of the separation device 8 is connected to the inlet of the drying device 9. After drying by the drying device 9, a lithium carbonate product is finally obtained. In the present application, the pretreatment device 1 performs preliminary pretreatment on the lithium-containing solution to remove impurities that are unnecessary for extraction, and the oil removal device uses an oil removal resin.

[0035] In addition, a device for recovering lithium carbonate from a lithium extraction solution in a salt lake also includes a waste gas treatment device 12, a cleaning device 13 and a waste water collection device 14. A vent pipe 201 is provided at the top of the extraction phase separation tank 2, and the waste gas treatment device 12 is connected to the vent pipe 201, so as to treat the toxic gas generated by the extraction. The cleaning device 13 is respectively connected to the lithium solution inlet end of the extraction phase separation tank 2 and the inlet end of the storage tank 3, and the bottom of the extraction phase separation tank 2 and the back extraction phase separation tank 5 are both provided with a waste water discharge pipe, and the waste water discharge pipe is connected to the waste water collection device 14. That is, the pipe intersection of the lithium solution inlet end of the phase separation tank and the inlet end of the storage tank 3 is connected by a tee 26, and the cleaning liquid of the cleaning device 13 enters the extraction phase separation tank 2 and the storage tank 3 respectively, and the cleaning liquid passing through the storage tank 3 passes through the pump group 4 and the back extraction phase separation tank 5 in turn, and finally the cleaning liquid enters the waste water collection device 14 through the waste water discharge pipe to reduce the pollution of the surrounding environment by waste water.

[0036] Reference Figure 1 and Figure 2 The waste gas treatment equipment 12 includes a gas collector 121, a gas purifier 122 and a gas recovery device 123. The gas collector 121 is connected to the vent pipe 201. One end of the gas purifier 122 is connected to the gas collector 121, and the other end is connected to the gas recovery device 123. During the extraction operation, the gas generated by the extraction enters the gas collector 121 through the vent pipe 201, and then is purified by the gas purifier 122 and recovered by the gas recovery device 123 for standby use, thereby realizing the recycling of toxic gases and reducing pollution to the surrounding environment.

[0037] Reference Figure 1 The outlet end of the oil separator 10 is connected to an adsorption tank 17, one end of the adsorption tank 17 is connected to the extraction phase separation tank 2, and the other end is also connected to the raffinate treatment equipment 18. Since the raffinate discharged by the extraction contains a small amount of oil layer, the oil separator 10 isolates these oil layers and then transports the raffinate to the adsorption tank 17. The adsorption tank 17 is provided with an aluminum-based adsorbent or an ion sieve-type oxide adsorbent with high selectivity and adsorption capacity for lithium, which can adsorb the unextracted lithium ions in the raffinate and send them back to the extraction phase separation tank 2 for secondary extraction. The remaining raffinate is then treated by the raffinate treatment equipment 18 and discharged to reduce pollution.

[0038] An alkali liquid tank 19 is provided at the outlet of the pretreatment device 1, and the alkali liquid tank 19 is connected to a pipeline at the outlet of the pretreatment device 1. Before the lithium-containing solution enters the extraction phase separation tank 2, the alkali liquid in the alkali liquid tank 19 is added to neutralize the acidic lithium-containing solution or change the pH of the lithium-containing solution.

[0039] A pressure regulating pump 20 is provided at the outlet of the cleaning device 13 to achieve high-pressure flushing of the device and pipelines; a pumping pump 21 is provided on the wastewater discharge pipeline to promptly pump out the wastewater generated by cleaning from the device and pipelines.

[0040] Reference Figure 1 and Figure 2 , the extraction phase separation tank 2 and the back extraction phase separation tank 5 are both provided with a stirring mechanism 15, the stirring mechanism 15 is vertically arranged in the extraction phase separation tank 2 and the back extraction phase separation tank 5, and the top of the extraction phase separation tank 2 and the back extraction phase separation tank 5 are fixedly provided with a driving mechanism 16, the stirring mechanism 15 is fixedly connected to the driving mechanism 16, and the driving mechanism 16 drives the stirring mechanism 15 to rotate, thereby achieving stirring. In addition, a sieve hole 151 is provided on the stirring mechanism 15 to enable the solution to freely penetrate from the sieve hole 151 during the stirring process, so that the extractant and the lithium-containing solution are mixed more fully. In the present application, the driving mechanism 16 is preferably a motor.

[0041] The solution inlet ends of the extraction phase separation tank 2 and the stripping phase separation tank 5 are both provided with flow meters 22, and the extraction phase separation tank 2 and the stripping phase separation tank 5 are both provided with temperature controllers 23 to achieve flow control and temperature control to prevent excessive flow rate, excessive high or low temperature.

[0042] Observation windows 24 are provided on the surfaces of the extraction phase separation tank 2 and the stripping phase separation tank 5 in the vertical direction, so that the operator can observe the conditions in the tank at any time to judge the degree of phase separation.

[0043] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A device for recovering lithium carbonate from a lithium extraction solution in a salt lake, comprising a pretreatment device (1), an extraction phase separation tank (2), a storage tank (3), a pump group (4), a stripping phase separation tank (5), an oil removal device (6), a lithium precipitation crystallization device (7), a separation device (8) and a drying device (9), wherein the pretreatment device (1), the extraction phase separation tank (2), the storage tank (3), the pump group (4), the stripping phase separation tank (5), the oil removal device (6), the lithium precipitation crystallization device (7), the separation device (8) and the drying device (9) are connected in sequence through pipelines; the top of the extraction phase separation tank (2) is connected to the storage tank (3), and the bottom of the extraction phase separation tank (2) is connected to an oil separator (10); the top of the stripping phase separation tank (5) is connected to an extractant tank (11), and the extractant tank (11) is connected to a lithium solution inlet of the extraction phase separation tank (2), and the bottom of the stripping phase separation tank (5) is connected to the oil removal device (6), characterized in that: It also includes waste gas treatment equipment (12), cleaning equipment (13) and waste water collection equipment (14); the top of the extraction phase separation tank (2) is provided with a vent pipe (201), and the waste gas treatment equipment (12) is connected to the vent pipe (201); the cleaning equipment (13) is respectively connected to the lithium solution inlet end of the extraction phase separation tank (2) and the inlet end of the storage tank (3); the bottoms of the extraction phase separation tank (2) and the stripping phase separation tank (5) are both provided with waste water discharge pipes, and the waste water discharge pipes are connected to the waste water collection equipment (14).

2. A device for recovering lithium carbonate from a salt lake lithium extraction solution according to claim 1, characterized in that: The waste gas treatment equipment (12) comprises a gas collector (121), a gas purifier (122) and a gas recovery device (123); the gas collector (121) is in communication with a gas discharge pipe (201); one end of the gas purifier (122) is connected to the gas collector (121) and the other end is connected to the gas recovery device (123).

3. The device for recovering lithium carbonate from a lithium extraction solution from a salt lake according to claim 1, characterized in that: A stirring mechanism (15) is provided in each of the extraction phase separation tank (2) and the stripping phase separation tank (5); a driving mechanism (16) is provided on the top of each of the extraction phase separation tank (2) and the stripping phase separation tank (5); the stirring mechanism (15) is fixedly connected to the driving mechanism (16); and a sieve hole (151) is provided on the stirring mechanism (15).

4. The device for recovering lithium carbonate from a lithium extraction solution from a salt lake according to claim 1, characterized in that: The outlet end of the oil separator (10) is connected to an adsorption tank (17); one end of the adsorption tank (17) is connected to an extraction phase separation tank (2), and the other end is connected to a raffinate treatment device (18).

5. The device for recovering lithium carbonate from a lithium extraction solution from a salt lake according to claim 1, characterized in that: An alkali liquid tank (19) is provided at the outlet end of the pretreatment equipment (1), and the alkali liquid tank (19) is connected to a pipeline at the outlet end of the pretreatment equipment (1).

6. The device for recovering lithium carbonate from a lithium extraction solution from a salt lake according to claim 1, characterized in that: A pressure regulating pump (20) is provided at the outlet end of the cleaning equipment (13), and a water pump (21) is provided on the wastewater discharge pipeline.

7. The device for recovering lithium carbonate from a lithium extraction solution from a salt lake according to claim 1, characterized in that: The solution inlet ends of the extraction phase separation tank (2) and the stripping phase separation tank (5) are both provided with flow meters (22).

8. The device for recovering lithium carbonate from a lithium extraction solution from a salt lake according to claim 1, characterized in that: The extraction phase separation tank (2) and the stripping phase separation tank (5) are both provided with a temperature controller (23).

9. The device for recovering lithium carbonate from a lithium extraction solution from a salt lake according to claim 1, characterized in that: Observation windows (24) are provided on the surfaces of the extraction phase separation tank (2) and the back extraction phase separation tank (5) along the vertical direction.

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