A new process for extracting lithium from salt lake with energy-efficient balanced utilization

Abstract

The application discloses a new process for extracting lithium from salt lakes with energy-efficient balanced utilization, and belongs to the technical field of new energy material preparation.The process comprises the following heat recycling steps: S1. low-grade heat recovery: using production water raw water as cooling water to recycle heat in the following processes: the adsorption lithium extraction process, the electrodialysis process and the nanofiltration reverse osmosis process; S2. medium-grade heat recovery: sending production water with recycled low-grade heat or / and reverse osmosis fresh water by-produced in the nanofiltration reverse osmosis process into the following processes to continue absorbing heat: the lithium carbonate process cooling section, the air compression process, the concentration process and the mother liquor recovery process; and S3. heat utilization: sending production water with recycled medium-grade heat or / and reverse osmosis fresh water as thermal desorption water into the adsorption lithium extraction process. The application realizes the application of a non-circulating water cooling system in the lithium extraction process from salt lakes for the first time, reduces investment cost and land occupation area, and realizes a revolutionary innovation on the traditional process.

Description

Technical Field

[0001] This invention belongs to the field of new energy material preparation technology, specifically relating to a new process for lithium extraction from salt lakes that utilizes energy efficiently and in a balanced manner. Background Technology

[0002] Lithium extraction from brine lakes is currently the primary source of basic lithium salts for battery-grade applications. Its core process involves extracting lithium from lithium-containing brine of a certain grade using techniques such as adsorption and extraction, for use in the production of battery-grade lithium carbonate and other products. The brine lithium extraction process requires cooling at multiple stages, including adsorption lithium extraction, nanofiltration reverse osmosis, electrodialysis, cooling of the finished product after lithium carbonate drying and calcination, lithium extraction from the lithium carbonate precipitation mother liquor, and air compressor cooling. The heat generated in these processes must be effectively removed. Simultaneously, significant heating is required by users in the brine lithium extraction process, such as heating the desorption water in the adsorption lithium extraction stage. Therefore, the energy balance of the brine lithium extraction system is crucial and a key factor in energy conservation and emission reduction.

[0003] Current lithium extraction processes from salt lakes typically employ a circulating water cooling system to cool the materials, while simultaneously using steam to heat the liquid. However, this approach increases investment costs and operating energy consumption, and also wastes water and energy resources, especially in arid and cold northern regions.

[0004] Therefore, developing a new process for lithium extraction from salt lakes with efficient and balanced energy utilization is of great significance for reducing production costs and improving resource utilization efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a new process for lithium extraction from salt lakes that utilizes energy efficiently and in a balanced manner, thereby improving resource utilization efficiency and reducing production costs.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] This invention discloses a novel energy-efficient and balanced lithium extraction process from salt lakes, comprising an adsorption lithium extraction step, an electrodialysis step, a nanofiltration reverse osmosis step, a lithium carbonate step, an air compression step, a concentration step, and a mother liquor recovery step. The process includes the following heat recovery and utilization steps:

[0008] S1. Low-grade heat recovery: Using raw production water as cooling water, heat is recovered from at least one of the following processes: adsorption lithium extraction process, electrodialysis process, and nanofiltration reverse osmosis process;

[0009] S2. Medium-grade heat recovery: The production water and / or the reverse osmosis desalination water byproduct of the nanofiltration reverse osmosis process that has recovered low-grade heat are sent to at least one of the following processes to continue absorbing heat: lithium carbonate process, air compression process, concentration process and mother liquor recovery process;

[0010] S3. Heat utilization: The production water and / or reverse osmosis desalination water that has recovered medium-grade heat is sent to the adsorption lithium extraction process as pyrolysis water.

[0011] In some embodiments of the present invention, the production water with recovered low-grade heat is sent to the cooling section of the lithium carbonate process and the air compression process to recover medium-grade heat; the reverse osmosis desalination water generated in the nanofiltration reverse osmosis process is sent to the concentration process and the mother liquor recovery process to recover medium-grade heat; the production water with recovered medium-grade heat and the reverse osmosis desalination water are combined and sent to the adsorption lithium extraction process as pyrolysis water.

[0012] In some embodiments of the present invention, during low-grade heat recovery, in the heat recovery step of the adsorption lithium extraction process, the raw production water and the qualified adsorption liquid are exchanged for heat to reduce the qualified adsorption liquid to 25~30°C before entering the nanofiltration reverse osmosis process; preferably, the raw production water and the qualified adsorption liquid are exchanged for heat via a heat exchanger.

[0013] In the heat recovery step of the nanofiltration reverse osmosis process, heat exchange is performed between the raw production water and the brine to reduce the temperature of the brine to 25~30℃; preferably, the raw production water and the brine are heat exchanged using a heat exchanger.

[0014] In the heat recovery step of the electrodialysis process, heat exchange is carried out between the raw production water and the electrodialysis concentrate. The raw production water cools the electrodialysis concentrate to 30~35℃. Preferably, a heat exchanger is installed on the electrodialysis concentrate side, and the raw production water and the electrodialysis concentrate exchange heat through the heat exchanger.

[0015] In some embodiments of the present invention, during the recovery of medium-grade heat, in the heat recovery step of the cooling section of the lithium carbonate process, the production water that has recovered low-grade heat and / or the reverse osmosis fresh water generated by the nanofiltration reverse osmosis process are indirectly heat-exchanged with high-temperature lithium carbonate to cool the lithium carbonate solid to 60°C; preferably, the medium-grade heat is recovered through indirect heat exchange in the lithium carbonate solid conveying spiral, cooling drum, or powder flow cooler.

[0016] In the heat recovery step of the air compressor process, the compression heat of the air compressor is removed by production water that has recovered low-grade heat or reverse osmosis desalination water produced by the nanofiltration reverse osmosis process, and the compressed air is cooled to 30~50℃, thereby recovering medium-grade heat.

[0017] In the heat recovery step of the concentration process, the production water with recovered low-grade heat and / or the reverse osmosis desalination water generated from the nanofiltration reverse osmosis process are used to cool the concentration evaporation tail gas, steam compressor lubricating oil, and vacuum pump liquid ring through a heat exchanger, thereby recovering medium-grade heat; preferably, the concentration evaporation tail gas is cooled to 30~40°C, and the vacuum pump liquid ring is cooled to 30~50°C; preferably, the concentration evaporation tail gas and vacuum pump liquid ring are cooled via a plate heat exchanger;

[0018] In the heat recovery step of mother liquor recovery, the production water with recovered low-grade heat and / or the reverse osmosis fresh water generated by the nanofiltration reverse osmosis process are used to exchange heat with the high-temperature lithium precipitation mother liquor through a heat exchanger to recover medium-grade heat; preferably, the heat exchange with the high-temperature lithium precipitation mother liquor is carried out through a plate heat exchanger.

[0019] In some embodiments of the present invention, the temperature of the production water in which low-grade heat has been recovered is 25~32°C.

[0020] In some embodiments of the present invention, the temperature of the production water in which medium-grade heat has been recovered is 30~40°C.

[0021] In some embodiments of the present invention, the pyrolysis water absorption temperature is 30~42℃, preferably 30~38℃.

[0022] In some embodiments of the present invention, the temperature of the reverse osmosis freshwater produced by the nanofiltration reverse osmosis process is 25~35°C.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This invention is scientifically designed and ingeniously conceived. For the first time, this invention has achieved the application of a non-circulating water cooling system in the lithium extraction process from salt lakes, reducing investment costs and floor space requirements, and realizing a disruptive innovation to traditional processes.

[0025] This invention uses production water and reverse osmosis desalination water as cooling water, and high-temperature water after heat recovery as pyrolysis water, thus achieving efficient and balanced utilization of energy.

[0026] This invention first recovers low-grade heat, then recovers medium-grade heat, and through a stepped cooling method, maximizes the utilization of cooling water and improves cooling efficiency.

[0027] This invention improves the operating efficiency of the entire lithium extraction system from salt lakes, achieving the goals of energy conservation and emission reduction. It has great potential for promotion in areas lacking water and steam resources.

[0028] In summary, the process of this invention not only reduces investment costs and land area, but also improves resource utilization efficiency, reduces energy consumption and production costs, and has great potential for promotion in areas lacking water and steam resources. Attached Figure Description

[0029] Appendix Figure 1 This is a process flow diagram of the present invention.

[0030] The corresponding names for the attached figures are: 101-first conveying pipe, 102-second conveying pipe. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] Example 1

[0033] As attached Figure 1 As shown, this invention discloses a novel energy-efficient and balanced lithium extraction process from salt lakes, comprising an adsorption lithium extraction step, an electrodialysis step, a nanofiltration reverse osmosis step, a lithium carbonate step, an air compression step, a concentration step, and a mother liquor recovery step, including the following steps:

[0034] S1. Low-grade heat recovery

[0035] The raw production water (temperature 9~20℃) is used as cooling water to recover heat from at least one of the following processes: adsorption lithium extraction process, electrodialysis process, and nanofiltration reverse osmosis process.

[0036] In the heat recovery step of the adsorption lithium extraction process, the raw production water and the qualified adsorption liquid are exchanged through a heat exchanger to cool the qualified adsorption liquid to 25~30℃ before entering the nanofiltration reverse osmosis process.

[0037] In the heat recovery step of the nanofiltration reverse osmosis process, the production water and brine are exchanged through a heat exchanger to reduce the temperature of the brine to 25~30℃.

[0038] In the heat recovery step of the electrodialysis process, heat exchange is carried out between the raw production water and the electrodialysis concentrate. The raw production water cools the electrodialysis concentrate to 30~35℃. Specifically, a heat exchanger is installed on the electrodialysis concentrate side, and the raw production water and the electrodialysis concentrate exchange heat through the heat exchanger.

[0039] S2. Medium-grade heat recovery

[0040] The production water (temperature 25~32℃) that has recovered low-grade heat is sent to at least one of the following processes to continue absorbing heat: lithium carbonate process, air compression process, concentration process and mother liquor recovery process;

[0041] In the heat recovery step of the lithium carbonate process, the production water with recovered low-grade heat is indirectly heat-exchanged with high-temperature lithium carbonate; preferably, the medium-grade heat is recovered through indirect heat exchange in the lithium carbonate solid conveying screw, cooling drum, or powder flow cooler.

[0042] In the heat recovery step of the air compressor process, the compression heat of the air compressor is removed by production water that has recovered low-grade heat, thereby recovering medium-grade heat.

[0043] In the heat recovery step of the concentration process, the production water with recovered low-grade heat is used to cool the concentration evaporation tail gas and the liquid ring of the vacuum pump through a plate heat exchanger, thereby recovering medium-grade heat.

[0044] In the heat recovery step of mother liquor recovery, production water with recovered low-grade heat is used to exchange heat with high-temperature lithium precipitation mother liquor through a plate heat exchanger to recover medium-grade heat.

[0045] S3. Heat utilization: Add a small amount of low-temperature raw water (9-20°C) to the production water (temperature 30-40°C) that has recovered medium-grade heat, mix and send it as thermal desorption desorption water (temperature 30-38°C) to the adsorption lithium extraction process.

[0046] Example 2

[0047] As attached Figure 1 As shown, this invention discloses a novel energy-efficient and balanced lithium extraction process from salt lakes, comprising an adsorption lithium extraction step, an electrodialysis step, a nanofiltration reverse osmosis step, a lithium carbonate step, an air compression step, a concentration step, and a mother liquor recovery step, including the following steps:

[0048] S1. Low-grade heat recovery

[0049] Raw production water (temperature 9~20℃) is used as cooling water to recover heat from the following processes: adsorption lithium extraction process, electrodialysis process, and nanofiltration reverse osmosis process.

[0050] In the heat recovery step of the adsorption lithium extraction process, the raw production water and the qualified adsorption liquid are exchanged through a heat exchanger to cool the qualified adsorption liquid to 25~30℃; the cooled qualified adsorption liquid enters the nanofiltration reverse osmosis process.

[0051] In the heat recovery step of the nanofiltration reverse osmosis process, the production water (temperature of 9~20℃) and the brine are exchanged through a heat exchanger to reduce the temperature of the brine to 25~30℃.

[0052] In the heat recovery step of the electrodialysis process, the raw production water (temperature 9~20℃) is used to exchange heat with the electrodialysis concentrate to cool the electrodialysis concentrate to 30~35℃. Specifically, a heat exchanger is set on the electrodialysis concentrate side, and the raw production water and the electrodialysis concentrate exchange heat through the heat exchanger.

[0053] S2. Medium-grade heat recovery

[0054] The production water (temperature 25~32℃) from which low-grade heat has been recovered is sent to the following processes to continue absorbing heat: lithium carbonate process and air compression process; the reverse osmosis desalination water (temperature 25~35℃) generated in the nanofiltration reverse osmosis process is sent to the concentration process and mother liquor recovery process to recover medium-grade heat;

[0055] In the heat recovery step of the lithium carbonate process, the production water with recovered low-grade heat is indirectly heat-exchanged with high-temperature lithium carbonate; specifically, medium-grade heat is recovered through indirect heat exchange in the lithium carbonate solid conveying screw, cooling drum, or powder flow cooler.

[0056] In the heat recovery step of the air compressor process, the compression heat of the air compressor is removed by production water that has recovered low-grade heat, and the compressed air is cooled to 30~50℃, thereby recovering medium-grade heat.

[0057] In the heat recovery step of the concentration process, reverse osmosis fresh water is used to cool the concentrated evaporation tail gas and the vacuum pump liquid ring through a plate heat exchanger to recover medium-grade heat; specifically, the concentrated evaporation tail gas is cooled to 30~40℃ and the vacuum pump liquid ring is cooled to 30~50℃.

[0058] In the heat recovery step of mother liquor recovery, reverse osmosis fresh water is used to exchange heat with high-temperature lithium precipitation mother liquor through a plate heat exchanger to cool the lithium precipitation mother liquor to 35~40℃ in order to recover medium-grade heat.

[0059] S3. Heat Utilization: The production water (temperature 30~40℃) and reverse osmosis fresh water (temperature 30~40℃) that have recovered medium-grade heat are combined and a small amount of low-temperature production water (temperature 9~20℃) is added before being sent to the adsorption lithium extraction process as thermal desorption water (temperature 30~38℃).

[0060] Example 3

[0061] As attached Figure 1 As shown, this invention discloses a novel energy-efficient and balanced lithium extraction process from salt lakes, comprising an adsorption lithium extraction step, an electrodialysis step, a nanofiltration reverse osmosis step, a lithium carbonate step, an air compression step, a concentration step, and a mother liquor recovery step, including the following steps:

[0062] S1. Low-grade heat recovery

[0063] Raw production water (temperature 9~20℃) is used as cooling water to recover heat from the following processes: adsorption lithium extraction process, electrodialysis process, and nanofiltration reverse osmosis process.

[0064] In the heat recovery step of the adsorption lithium extraction process, the raw production water and the qualified adsorption liquid are exchanged through a heat exchanger to cool the qualified adsorption liquid to 25~30℃; the cooled qualified adsorption liquid enters the nanofiltration reverse osmosis process.

[0065] In the heat recovery step of the nanofiltration reverse osmosis process, the production water (temperature of 9~20℃) and the brine are exchanged through a heat exchanger to reduce the temperature of the brine to 25~30℃.

[0066] In the heat recovery step of the electrodialysis process, the raw production water (temperature 9~20℃) is used to exchange heat with the electrodialysis concentrate to cool the electrodialysis concentrate to 30~35℃. Specifically, a heat exchanger is set on the electrodialysis concentrate side, and the raw production water and the electrodialysis concentrate exchange heat through the heat exchanger.

[0067] S2. Medium-grade heat recovery

[0068] The production water, after recovering low-grade heat, enters the following processes via the first conveying pipe 101: lithium carbonate process, air compression process, concentration process, and mother liquor recovery process; the reverse osmosis desalination water produced by the nanofiltration reverse osmosis process is discharged from the nanofiltration reverse osmosis process via the second conveying pipe 102, which is connected to the first conveying pipe 101. Valves are installed on both the first conveying pipe 101 and the second conveying pipe 102.

[0069] The lithium carbonate process, air compressor process, concentration process, and mother liquor process can switch the type of cooling water used and adjust its flow rate according to the cooling water consumption and water quality. The specific types of cooling water are as follows: production water with recovered low-grade heat, or reverse osmosis desalination water, or a mixture of production water with recovered low-grade heat and reverse osmosis desalination water;

[0070] Specifically:

[0071] In the heat recovery step of the lithium carbonate process, cooling water is indirectly exchanged with high-temperature lithium carbonate; specifically, intermediate-grade heat is recovered through indirect heat exchange in a lithium carbonate solid conveying screw, cooling drum, or powder flow cooler.

[0072] In the heat recovery step of the air compressor process, cooling water is used to remove the heat of compression from the air compressor and cool the compressed air to 30~50℃, thereby recovering medium-grade heat.

[0073] In the heat recovery step of the concentration process, cooling water is used to cool the concentrated evaporation tail gas and the vacuum pump liquid ring through a plate heat exchanger to recover medium-grade heat; specifically, the concentrated evaporation tail gas is cooled to 30~40℃ and the vacuum pump liquid ring is cooled to 30~50℃.

[0074] In the heat recovery step of mother liquor recovery, cooling water is used to exchange heat with the high-temperature lithium precipitated mother liquor through a plate heat exchanger to cool the lithium precipitated mother liquor to 35~40℃ in order to recover medium-grade heat.

[0075] S3. Heat Utilization: Cooling water (temperature 30~40℃) that has recovered medium-grade heat is combined and a small amount of low-temperature production water (temperature 9~20℃) is added before being sent to the adsorption lithium extraction process as thermal desorption water (temperature 30~38℃).

[0076] This invention uses the makeup water from lithium adsorption desorption, namely production water and desalinated water from reverse osmosis, as the source. It indirectly exchanges heat with materials requiring heat exchange in the process. The temperature of the production water and reverse osmosis desalinated water reaches the temperature requirement of the desorption water, thus avoiding the consumption of circulating water. Simultaneously, the materials requiring cooling are cooled, achieving two benefits at once. In this invention's process, potentially wasteful thermal energy is effectively utilized in stages, maximizing energy recovery and reuse. It ensures the rational use of cooling water and thermal desorption water, reducing dependence on external cooling water and steam resources, and lowering energy consumption and production costs.

[0077] Using the process of this embodiment, taking the extraction of lithium from brine with a lithium concentration of 0.2 g / L as an example, for every 10,000 tons of lithium carbonate produced, approximately 4.18 million tons of circulating cooling water and approximately 72,000 tons of steam can be saved.

[0078] The above description is merely a preferred embodiment of the invention and does not constitute any limitation on the invention. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments based on the technical essence of the invention and within the spirit and principles of the invention shall still fall within the protection scope of the invention's technical solution.

Claims

1. A new process for extracting lithium from salt lakes with energy-efficient balanced utilization, comprising an adsorption lithium extraction process, an electrodialysis process, a nanofiltration reverse osmosis process, a lithium carbonate process, an air compression process, a concentration process, and a mother liquor recovery process, characterized in that, The process comprises the following heat recovery steps: S1. Low-grade heat recovery: using production water raw water as cooling water, recovering heat in at least one of the following processes: lithium adsorption process, electrodialysis process, nanofiltration reverse osmosis process; S2. Medium-grade heat recovery: sending production water recovered from low-grade heat or / and reverse osmosis fresh water produced in the nanofiltration reverse osmosis process into at least one of the following processes to continue to absorb heat: lithium carbonate process, air compression process, concentration process and mother liquor recovery process; S3. Heat utilization: sending production water recovered from medium-grade heat or / and reverse osmosis fresh water as thermal desorption water into the lithium adsorption process. 2.The salt lake lithium extraction process with energy-efficient balanced utilization according to claim 1, characterized in that, Production water recovered from low-grade heat is sent into the cooling section of the lithium carbonate process and the air compression process to recover medium-grade heat; reverse osmosis fresh water produced in the nanofiltration reverse osmosis process is sent into the concentration process and the mother liquor recovery process to recover medium-grade heat; production water and reverse osmosis fresh water recovered from medium-grade heat are combined and sent into the lithium adsorption process as thermal desorption water. 3.The salt lake lithium extraction process of claim 1 or 2, wherein, In the heat recovery step of the lithium adsorption process, production water raw water is used to exchange heat with adsorption qualified liquid to reduce the temperature of the adsorption qualified liquid to 25-30℃ for entering the nanofiltration reverse osmosis process; In the heat recovery step of the nanofiltration reverse osmosis process, production water raw water is used to exchange heat with bittern to reduce the temperature of the bittern to 25-30℃; In the heat recovery step of the electrodialysis process, production water raw water is used to exchange heat with electrodialysis concentrated liquid to reduce the temperature of the electrodialysis concentrated liquid to 30-35℃.

4. The new process for extracting lithium from salt lakes with energy-efficient balanced utilization according to claim 3, characterized in that, Production water raw water and adsorption qualified liquid are exchanged through a heat exchanger.

5. The new process for extracting lithium from salt lakes with energy-efficient balanced utilization according to claim 3, characterized in that, Production water raw water and bittern are exchanged through a heat exchanger.

6. The new process for extracting lithium from salt lakes with energy-efficient balanced utilization according to claim 3, characterized in that, A heat exchanger is arranged on the side of the electrodialysis concentrated liquid, and production water raw water and electrodialysis concentrated liquid are exchanged through the heat exchanger.

7. The new process for extracting lithium from salt lakes with energy-efficient balanced utilization according to claim 2, characterized in that, In the heat recovery step of the cooling section of the lithium carbonate process, production water recovered from low-grade heat or / and reverse osmosis fresh water produced in the nanofiltration reverse osmosis process is used to exchange heat with high-temperature lithium carbonate indirectly to reduce the temperature of the lithium carbonate solid to 60℃; In the heat recovery step of the air compression process, production water recovered from low-grade heat or / and reverse osmosis fresh water produced in the nanofiltration reverse osmosis process is used to remove the compression heat of the air compressor to reduce the temperature of the air compression gas to 30-50℃, thereby recovering medium-grade heat; In the heat recovery step of the concentration process, production water recovered from low-grade heat or / and reverse osmosis fresh water produced in the nanofiltration reverse osmosis process is used to cool the concentrated evaporation tail gas, steam compressor lubricating oil system and vacuum pump liquid ring through a heat exchanger, thereby recovering medium-grade heat, cooling the concentrated evaporation tail gas to 30-40℃ and cooling the vacuum pump liquid ring to 30-50℃; In the heat recovery step of the mother liquor recovery, production water recovered from low-grade heat or / and reverse osmosis fresh water produced in the nanofiltration reverse osmosis process is used to exchange heat with high-temperature lithium precipitation mother liquor through a heat exchanger to cool the lithium precipitation mother liquor to 35-40℃ to recover medium-grade heat. 8.The salt lake lithium extraction process of claim 7, wherein, Medium-grade heat is recovered indirectly through the exchange between the lithium carbonate solid conveying screw or the cooling roller or the powder flow cooler. 9.The salt lake lithium extraction process of claim 7, wherein, The concentrated evaporation tail gas and the vacuum pump liquid ring are cooled through a plate heat exchanger or a shell-and-tube cooler.

10. The new process for extracting lithium from salt lakes with energy-efficient balanced utilization according to claim 7, characterized in that, Heat exchange with high-temperature lithium precipitation mother liquor through plate heat exchanger.

11. The new process for lithium extraction from salt lakes with energy-efficient balanced utilization according to claim 1, characterized by the fact that The temperature of the production water recovering low-grade heat is 25-32℃.

12. The new process for lithium extraction from salt lakes with energy-efficient balanced utilization according to claim 1, characterized by the fact that The temperature of the production water recovering medium-grade heat is 30-40℃.

13. The new process for lithium extraction from salt lakes with energy-efficient balanced utilization according to claim 1, characterized by the fact that The temperature of the thermal desorption water is 30-42℃.

14. The new process for lithium extraction from salt lakes with energy-efficient balanced utilization according to claim 13, characterized by the fact that The temperature of the thermal desorption water is 30-38℃.

15. The new process for lithium extraction from salt lakes with energy-efficient balanced utilization according to claim 1, characterized by the fact that The temperature of the reverse osmosis fresh water produced by the nanofiltration reverse osmosis process is 25-35℃.

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