A steam condensation adsorption device and production process for extracting lithium from salt lake brine

Abstract

A steam condensation adsorption tower device system for extracting lithium from plateau salt lake brine belongs to the technical field of salt lake lithium extraction process. The condenser of the multi-effect evaporation system and the traditional adsorption tower are coupled into one, achieving the optimal temperature for the salt lake brine lithium adsorption process and improving the adsorption efficiency of the adsorption tower for lithium ions. The secondary steam generated in the last-effect evaporator is condensed in the multi-process tube bundle to release the latent heat of vaporization, which directly heats the salt lake brine adsorption and desorption process, which not only enhances the adsorption rate of the salt lake brine lithium, but also preheats the fresh water required for the subsequent desorption process, thereby reducing the energy consumption cost of salt lake lithium extraction. The condensation heat exchange tube bundle process is rationally arranged to optimize the temperature of the adsorbent and salt lake brine at different positions in the adsorption tower, so that the temperature of the adsorbent and salt lake brine gradually increases from top to bottom in the adsorption tower. The temperature increase from top to bottom in the adsorption tower compensates for the decrease in adsorption rate caused by the decrease in lithium ion concentration.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium extraction technology from salt lakes, and in particular relates to a steam condensation adsorption device for extracting lithium from salt lake brine and a production process for lithium extraction and adsorption using the device. Background Art

[0002] The main lithium extraction technologies for salt lake brine include precipitation, adsorption, solvent extraction, membrane separation, electrochemical method, calcination, and solar pond method. Compared with other lithium extraction technologies, adsorption has the advantages of low requirements for the magnesium-to-lithium ratio of the brine, high elution rate, simple process, strong stability, high product purity, low energy consumption and cost, and environmental protection. It is suitable for salt lake brines with low lithium content and high magnesium-to-lithium ratio. Therefore, this method has become the most promising lithium extraction technology for plateau salt lake brines.

[0003] The key technologies for the adsorption method are the selection of lithium ion adsorbents and the optimization of adsorption operating parameters. Research on the adsorption method focuses on developing high-capacity, low-cost, and recyclable adsorbents. The optimal temperature for lithium ion adsorption and desorption is required to be above 50°C. However, for the low-temperature salt lake brine of the Qinghai-Tibet Plateau, with an average annual temperature of 4°C, achieving this optimal adsorption temperature requires a significant amount of heat. The lack of electricity and fossil fuels on the Qinghai-Tibet Plateau makes existing adsorption lithium extraction methods energy-intensive and cost-prohibitive. Developing an adsorption device and production process suitable for lithium extraction from salt lake brine on the Qinghai-Tibet Plateau is a pressing challenge.

[0004] Chinese patent publication number CN213313473U discloses a novel lithium extraction system for adsorption and concentration of lithium-containing brine. The system integrates the adsorption, desorption, and concentration of lithium ions. Chinese patent publication number CN219058781U discloses a lithium extraction assembly for lithium-containing salt lake brine. This assembly overcomes the single function of salt lake brine solar pools and implements multiple processes including evaporation, crystallization, and filtration. Chinese patent publication number CN110606499A discloses a lithium extraction assembly for lithium-containing salt lake brine. This assembly combines evaporation crystallization, nanofiltration, ion exchange, and monovalent electrodialysis to separate magnesium and lithium. The above invention patents are an integration of existing salt lake lithium extraction processes. They do not consider operating parameters such as brine temperature and concentration during the adsorption lithium extraction process, do not involve reducing the energy consumption of the adsorption process, and cannot be used to reduce the energy consumption cost of lithium extraction from plateau salt lake brine.

[0005] Chinese Patent Publication No. CN118813977A discloses a method and adsorption tower for extracting lithium from carbonate-type salt lake brine, which improves the recovery efficiency of lithium adsorbents by adjusting the pH value of the salt lake brine. Chinese Patent Publication No. CN118812040A discloses a lithium extraction adsorption and desorption tower device, which uses two or more towers of the same structure to extract lithium from oil and gas field produced water. Chinese Patent Publication No. CN111621640B discloses an adsorption tower and method for extracting lithium from salt lake brine, which shortens the adsorption time by introducing liquid from the bottom of the adsorption tower and discharging liquid from the top. Chinese Patent Publication No. CN221740387U discloses an adsorption device for efficiently extracting lithium from lithium-precipitated mother liquor using titanium-based adsorbents, which solves problems such as adsorbent bed compaction, solidification, and wear, and significantly reduces the production cost of adsorbent replenishment. The above patents on lithium extraction adsorption towers do not address the temperature of the adsorption process, but only optimize the adsorption tower process or adsorbent loading structure.

[0006] Chinese patent publication number CN215444173U discloses a coupled system for supercritical carbon dioxide cycle power generation and brine lithium extraction. This system utilizes waste heat from the supercritical carbon dioxide cycle, which is then upgraded through an absorption heat pump for use in the lithium extraction process. However, the supercritical carbon dioxide cycle power generation system requires a high-temperature heat source, and the absorption heat pump consumes electricity. Increasing the temperature of the adsorption process requires high-quality electricity and heat energy, making it unsuitable for the actual situation of the Qinghai-Tibet Plateau where there is a shortage of electricity and fossil fuels.

[0007] To summarize the above: In the prior art, the problems existing in the salt lake brine lithium extraction adsorption tower device and production process are as follows:

[0008] (1) The adsorption process of salt lake brine in the adsorption tower is an endothermic reaction. The optimal adsorption temperature of commonly used aluminum salt adsorbents is 50-60°C. The annual average temperature of salt lake brine in the Qinghai-Tibet Plateau is 4°C. The efficiency of direct adsorption of salt lake brine in the adsorption tower is too low. The Qinghai-Tibet Plateau lacks fossil fuels and electricity. The energy consumption cost of directly consuming electricity and fuel to heat salt lake brine is too high.

[0009] (2) In the process of lithium extraction from salt lakes, the adsorbed lithium solution is concentrated through a multi-effect evaporation system. The 55°C secondary steam generated by the last evaporator in the multi-effect evaporation system is condensed by the adsorbed lithium solution in the condenser. The adsorbed lithium solution is preheated and then enters the evaporator for evaporation, thereby improving the thermal efficiency of the multi-effect evaporation system. The improvement of the thermal efficiency of the multi-effect evaporation system is at the expense of the temperature of the lithium ion adsorption process of the salt lake brine. The lithium ion adsorption efficiency of the low-temperature salt lake brine is too low, making it difficult to effectively reduce the total energy consumption cost of lithium extraction from salt lakes.

[0010] (3) If the 55°C secondary steam generated by the final evaporator does not enter the condenser but directly enters the heat exchanger to preheat the salt lake brine, the preheated salt lake brine enters the adsorption tower and contacts the adsorbent at ambient temperature to complete the adsorption process. Due to the temperature difference at the heat transfer end of the preheater, the temperature of the salt lake brine after preheating in the preheater is below 50°C. The adsorption reaction temperature between the preheated salt lake brine and the adsorbent at ambient temperature in the adsorption tower is lower than the lower limit of the optimal adsorption temperature of 50°C. Therefore, using secondary steam to directly heat the salt lake brine cannot guarantee the temperature conditions for the adsorption reaction.

[0011] (4) As the salt lake brine enters from the upper part of the adsorption tower and flows downward, the lithium ions in the salt lake brine are adsorbed by the adsorbent, and its lithium ion concentration gradually decreases, and the adsorption rate of the salt lake brine gradually decreases. As a result, when the adsorbent in the upper part of the adsorption tower reaches saturation, the adsorbent in the lower part has not yet reached saturation, which reduces the overall adsorption rate of the adsorption tower. Summary of the Invention

[0012] In order to overcome the shortcomings of the existing technology, the present invention proposes a steam condensation adsorption device and production process for extracting lithium from salt lake brine.

[0013] The characteristics of the present invention are: developing a steam condensation adsorption tower device that couples the final secondary steam condensation process in the lithium solution multi-effect evaporation system with the salt lake lithium extraction adsorption process, utilizing the vaporization latent heat released by the condensation of the secondary steam generated by the final evaporator to directly act on the salt lake brine adsorption and desorption process, and the vaporization latent heat released by the condensation of the 55°C secondary steam in the tube is used to heat the aluminum salt adsorbent in the adsorption tower outside the tube and spray the salt lake brine, so that the lithium adsorption process of the salt lake brine is maintained at an optimal temperature of above 50°C; in the adsorption tower, the salt lake brine flows downward and collides with the heat exchange tube and the adsorbent particles, so that The size of the salt lake brine spray droplets is reduced and they are suspended with the adsorbent particles, which increases the contact area of ​​the adsorption reaction and strengthens the heat transfer between the steam condensation in the tube and the brine droplets and adsorbent particles outside the tube, thereby improving the adsorption efficiency of lithium extraction from the salt lake; a multi-process steam condensation heat exchange tube bundle is arranged in the steam condensation adsorption tower device, and the overall adsorption efficiency in the adsorption tower is improved by reasonably arranging the heat exchange tube bundle process; the waste heat of the hot salt lake brine after the adsorption is completed is used to preheat the fresh water in the subsequent desorption process, and the preheated fresh water is used to leach the hot saturated adsorbent, which is beneficial to reducing the energy consumption cost of lithium extraction from the salt lake.

[0014] The specific technical solution of the present invention is described as follows: A steam condensation adsorption device for extracting lithium from salt lake brine, which includes an adsorption tower unit and a lithium solution concentration unit, wherein the adsorption tower unit includes a salt lake water pump, a four-way stopcock, a steam condensation adsorption tower, a hot brine tank, a heat exchanger, a fresh water tank, a fresh water pump and a three-way stopcock; the steam condensation adsorption tower includes a sprayer, a plurality of process tube bundles, and each process tube bundle is provided with a pipe box, a terminal condensation water tank and an adsorbent; the salt lake water pump is connected to the four-way stopcock. The steam condensing adsorption tower is connected to the lithium solution concentration unit through a steam pipeline, and several stages of tube bundles are connected to the pipe box and then to the terminal condensate water tank. Multiple pipe boxes and the terminal condensate water tank are connected to the fresh water tank. The outlet of the steam condensing adsorption tower is connected to the three-way plug valve, which is also connected to the hot brine tank. The hot brine tank is connected to the heat exchanger, and the heat exchanger is also connected to the fresh water tank.

[0015] The lithium solution concentration unit includes a booster pump, a nanofiltration membrane device, a two-stage evaporator, a lithium carbonate precipitation device, a three-way stopcock and a magnesium solution tank; the three-way stopcock is connected to the booster pump, the booster pump is connected to the nanofiltration membrane device, the nanofiltration membrane device is connected to the second evaporator through a pipeline, and the nanofiltration membrane device is also connected to the magnesium solution tank; a first evaporator heat exchange tube bundle is arranged in the first evaporator, the first evaporator exhaust hole is connected to the first evaporator secondary steam outlet, the second evaporator heating steam inlet and the second evaporator heat exchange tube bundle through a pipeline, the second evaporator concentrated liquid outlet is connected to the first evaporator sprayer through the first evaporator feed liquid inlet, the first evaporator concentrated liquid outlet is connected to the lithium carbonate precipitation device, the second evaporator feed liquid inlet is connected to the second evaporator sprayer, the second evaporator exhaust hole is connected to the second evaporator secondary steam outlet and the steam inlet pipe box of the adsorption tower device in sequence through a pipeline, and the second evaporator condensate outlet and the first evaporator condensate outlet are connected to the lower inlet of the fresh water tank through the three-way stopcock.

[0016] A production process for extracting lithium from salt lake brine, comprising the following steps:

[0017] Step 1: The salt lake brine is pressurized by the salt lake water pump and enters the sprayer through the four-way plug valve. The salt lake brine is sprayed onto the surface of the adsorbent in the steam condensation adsorption tower through the sprayer;

[0018] Step 2: Constant-temperature steam enters several process tube bundles and pipe boxes in series step by step; the condensate in the process tube bundle at the end enters the end pipe box through the end condensate tank; the outlets of each pipe box and the end pipe box are collected, and the collected condensate enters the fresh water tank;

[0019] Step 3: The aluminum salt adsorbent in the steam condensation absorption tower and several process tube bundles form a fluidized bed heat exchanger. During the adsorption process, the salt lake brine sprayed by the sprayer sequentially impacts the several process tube bundles, and the aluminum salt adsorbent exchanges heat with the impacted process tube bundles, and the aluminum salt adsorbent adsorbs magnesium and lithium ions in the salt lake brine. The hot brine that has completed the adsorption process is collected at the bottom of the steam condensation absorption tower and enters the hot brine tank through a three-way stopcock.

[0020] Step 4: The hot brine in the hot brine tank forms a hot brine closed circulation loop between the hot brine tank and the heat exchanger, and the cold fresh water in the fresh water tank forms a cold fresh water closed circulation loop between the fresh water tank and the heat exchanger; the hot brine in the hot brine closed circulation loop of the heat exchanger heats the fresh water in the cold fresh water closed circulation loop, and the fresh water temperature rises to 45-47°C;

[0021] Step 5: During the desorption process, the preheated fresh water in the fresh water tank is pressurized by the fresh water pump and then enters the sprayer through a four-way stopcock valve. The sprayed fresh water and aluminum salt adsorbent form a thin liquid film on the outside of the heat exchange tube walls of several process tube bundles. Under the impact of the fresh water, the collision between the aluminum salt adsorbent and the heat exchange tube wall realizes heat exchange. The fresh water and aluminum salt adsorbent outside the tube bundle absorb the latent heat of vaporization released by the condensation of steam in the tube bundle, and the temperature rises to 50-52°C. The magnesium and lithium ions adsorbed by the aluminum salt adsorbent are desorbed from the fresh water. After desorption, the magnesium and lithium solution at 50-52°C is collected at the bottom of the steam condensation adsorption tower.

[0022] Step 6: The magnesium and lithium solutions at 50-52° C. sequentially pass through the outlet of the steam condensation adsorption tower into the three-way stopcock, are pressurized by the booster pump, and enter the nanofiltration membrane device to complete the separation of magnesium ions. The lithium solution after the magnesium ions are removed is used as the feed liquid and passes through the nanofiltration membrane device and the second evaporator. The solution rich in magnesium ions flows into the magnesium solution tank through the concentrated solution outlet of the nanofiltration membrane device;

[0023] Step 7: The lithium solution is sprayed onto the outer surface of the second evaporator heat exchange tube bundle, and the liquid film outside the tube bundle absorbs the heat released by the condensation of steam in the tubes of the second evaporator heat exchange tube bundle; the evaporated and concentrated lithium solution is collected at the bottom of the second evaporator, flows into the first evaporator sprayer through the second evaporator, and the concentrated lithium solution from the first evaporator sprayer is sprayed onto the outer surface of the first evaporator heat exchange tube bundle to form a uniform liquid film. The liquid film outside the tube bundle absorbs the heat released by the condensation of steam in the tubes of the first evaporator heat exchange tube bundle. The further evaporated and concentrated saturated lithium solution is collected at the bottom of the first evaporator and flows into the lithium carbonate precipitation device;

[0024] Step 8: 65℃ heating steam is used as the heat source for evaporating and concentrating the lithium solution. oneThe evaporator enters the first evaporator heat exchange tube bundle to condense and release heat. The steam generated by the evaporation of the lithium solution outside the first evaporator heat exchange tube bundle mixes with the uncondensed steam in the first evaporator heat exchange tube bundle through the first evaporator exhaust hole. The mixed steam enters the second evaporator heat exchange tube bundle through the first evaporator secondary steam outlet and the second evaporator heating steam inlet, serving as a heat source for evaporating the lithium solution in the second evaporator. The steam generated by the evaporation of the lithium solution outside the second evaporator heat exchange tube bundle mixes with the uncondensed steam in the second evaporator heat exchange tube bundle through the second evaporator exhaust hole. The mixed steam enters the steam inlet pipe box through the second evaporator secondary steam outlet. The condensate in the second evaporator and the first evaporator flows into the fresh water tank respectively through three-way stopcocks.

[0025] Step 9: The saturated concentrated lithium solution flowing out of the first evaporator is dehydrated in a lithium carbonate precipitation device to obtain high-purity lithium carbonate solid.

[0026] Beneficial effects of the present invention:

[0027] (1) Develop a steam condensation adsorption tower for lithium extraction from plateau salt lakes. This device integrates the condenser of a multi-effect evaporation system with a traditional adsorption tower, and has both steam condensation and lithium adsorption functions. Without increasing equipment investment and energy consumption, it ensures the adsorption temperature and adsorption reaction rate of the salt lake brine lithium extraction adsorption tower. After the salt lake brine and aluminum salt adsorbent are heated, the salt lake lithium extraction adsorption temperature is increased, and the optimal adsorption temperature is guaranteed without additional consumption of electricity and heat energy. The collision between the salt lake brine and the heat exchange tube wall reduces the size of the salt lake brine spray droplets and increases the surface area of ​​the droplets. The collision between the adsorbent particles and the heat exchange tube wall causes the adsorbent to become suspended, increasing the solid-liquid contact area between the adsorbent particle surface and the salt lake brine, strengthening the steam condensation inside the tube and the heat transfer between the salt lake brine droplets outside the tube and the adsorbent particles, ensuring the optimal temperature of the adsorption reaction, and improving the salt lake brine lithium extraction adsorption rate.

[0028] (2) The final secondary steam condensation is coupled with the adsorption process, that is, the latent heat of vaporization released by the condensation of the secondary steam generated in the final evaporator is used to heat the salt lake brine adsorption and desorption process, and the heat released by the condensation of the steam in the tube is used to heat the aluminum salt adsorbent in the adsorption tower outside the tube and the sprayed salt lake brine, so that the optimal adsorption temperature of the salt lake brine lithium adsorption process is above 50 ° C; the hot brine after adsorption is preheated by a plate heat exchanger for the subsequent desorption process. The preheated fresh water is used to elute the hot saturated adsorbent, and the hot lithium solution obtained from the bottom of the adsorption tower is used as the feed liquid of the multi-effect evaporation system after the nanofiltration process. That is, the heat of the secondary steam condensation in the final evaporator is used to achieve the dual effects of heating the adsorption and desorption processes and preheating the feed liquid of the multi-effect evaporation process.

[0029] (3) By rationally arranging the condensation heat exchange tube bundle process, the temperature of the adsorbent and salt lake brine at different positions in the adsorption tower is optimized. That is, the temperature of the adsorbent and salt lake brine gradually increases from top to bottom in the adsorption tower. By increasing the temperature of the adsorbent and salt lake brine at the bottom of the tower, the adsorption rate of lithium in the salt lake brine is increased. A multi-process design is adopted, with the steam inlet at the top of the tower. The first process has the largest number of tube rows and a large condensation heat exchange capacity. The temperature of the adsorbent and salt lake brine rises to the lower limit of the optimal adsorption temperature. The number of tube rows in the second and third processes decreases in turn, the condensation heat exchange capacity decreases, and the temperature of the adsorbent and salt lake brine increases slightly in turn. The adsorption rate decreases due to the decrease in lithium ion concentration by increasing the temperature from top to bottom in the adsorption tower. The overall adsorption rate in the adsorption tower is improved through the rational design of the condensation heat exchange device. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a steam condensation adsorption device and production process diagram for extracting lithium from plateau salt lake brine disclosed in the present invention.

[0031] In the picture:

[0032] 1. Salt lake water pump;

[0033] 2. Four-way plug valve, 21. Four-way plug valve for salt lake brine inlet, 22. Four-way plug valve for salt lake brine outlet, 23. Four-way plug valve for fresh water outlet, 24. Four-way plug valve for fresh water inlet;

[0034] 3. Sprinkler, 31. Water inlet of the sprinkler, 32. Water outlet of the sprinkler;

[0035] 4. Steam inlet pipe box;

[0036] 5. One-process management;

[0037] 6. Second process pipe box, 61. Second process pipe box inlet, 62. Second process pipe box steam outlet, 63. Second process pipe box condensate outlet;

[0038] 7. Three-process pipe box, 71. Three-process pipe box inlet, 72. Three-process pipe box steam outlet, 73. Three-process pipe box condensate outlet;

[0039] 8. Second process control;

[0040] 9. Three-process management;

[0041] 10. Terminal pipe box, 101. Terminal pipe box inlet, 102. Terminal pipe box outlet;

[0042] 11. steam condensation absorption tower, 111. water outlet of the steam condensation absorption tower;

[0043] 12. Aluminum salt adsorbent;

[0044] 13. Hot brine tank, 131. Upper inlet of hot brine tank, 132. Lower outlet of hot brine tank, 133. Lower inlet of hot brine tank;

[0045] 14. Heat exchanger, 141. Heat exchanger hot brine side inlet, 142. Heat exchanger hot brine side outlet, 143. Heat exchanger fresh water side inlet, 144. Heat exchanger fresh water side outlet;

[0046] 15. Fresh water tank, 151. Middle fresh water tank inlet, 152. Upper fresh water tank outlet, 153. Upper fresh water tank inlet, 154. Lower fresh water tank outlet, 155. Lower fresh water tank inlet;

[0047] 16. Fresh water pump;

[0048] 17. Three-way plug valve I, 171. Three-way plug valve inlet, 172. Three-way plug valve hot brine outlet, 173. Three-way plug valve magnesium-lithium solution outlet;

[0049] 18. Booster pump;

[0050] 19. Nanofiltration membrane device, 191. Nanofiltration membrane device inlet, 192. Nanofiltration membrane device outlet, 193. Nanofiltration membrane device concentrate outlet;

[0051] 20. Second evaporator, 201. Second evaporator feed liquid inlet, 202. Second evaporator concentrated liquid outlet, 203. Second evaporator heating steam inlet, 204. Second evaporator secondary steam outlet, 205. Second evaporator condensate outlet, 206. Second evaporator sprayer, 207. Second evaporator heat exchange tube bundle, 208. Second evaporator steam exhaust port;

[0052] 25. Magnesium solution tank; 26. Three-way stopcock valve II; 27. Lithium carbonate precipitation device;

[0053] 28. First evaporator, 281. Feed liquid inlet of first evaporator, 282. Concentrated liquid outlet of first evaporator, 283. Secondary steam outlet of first evaporator, 284. Heating steam inlet of first evaporator, 285. Condensate outlet of first evaporator, 286. Sprayer of first evaporator, 287. Heat exchange tube bundle of first evaporator, 288. Exhaust hole of first evaporator. DETAILED DESCRIPTION

[0054] The present invention is described in detail below through specific embodiments. Those familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. However, it should be noted that the following specific embodiments do not limit the technical solution. Those skilled in the art can make further technical extensions under the guidance of the following technical solution. The scope of protection of this patent application shall be based on the claims.

[0055] Example 1: (Connection structure of the adsorption device)

[0056] Figure 1 The device is a steam condensation adsorption device for extracting lithium from plateau salt lake brine, which includes an adsorption tower device unit on the left and a lithium solution concentration unit on the right; the adsorption tower device unit on the left includes a salt lake water pump 1, a four-way plug valve 2, a steam condensation adsorption tower 11, a hot brine tank 13, a heat exchanger 14, a fresh water tank 15, a fresh water pump 16 and a three-way plug valve I 17; the steam condensation adsorption tower 11 includes a sprayer 3, a steam inlet pipe box 4, a first process tube bundle 5, a second process tube bundle 8, a third process tube bundle 9, and a second process tube bundle 10. Tube bundle 9, second process pipe box 6, third process pipe box 7, terminal condensate water tank 10 and aluminum salt adsorbent 12; the salt lake water pump 1 is connected to the salt lake water inlet 21 of the four-way plug valve, the fresh water outlet 22 of the four-way plug valve and the salt lake water outlet 23 of the four-way plug valve are connected to the sprinkler 3 and the sprinkler outlet 32 ​​through the pipeline through the sprinkler water inlet 31, and the lower outlet 154 of the fresh water tank is connected to the fresh water inlet 24 of the four-way plug valve through the fresh water pump 16; the steam inlet pipe box in the steam condensation adsorption tower 11 4 is connected to the lithium solution concentration unit through a pipeline, the first process tube bundle 5 is connected to the second process tube box inlet 61, the second process tube box steam outlet 62 is connected to the second process tube bundle 8 and then to the third process tube box inlet 71, the third process tube box steam outlet 72 is connected to the third process tube bundle 9 and then to the terminal tube box inlet 101, the second process tube box condensate outlet 63, the third process tube box condensate outlet 73 and the terminal tube box outlet 102 are connected to the middle inlet 151 of the fresh water tank, and the steam condensation type suction The auxiliary tower outlet 111 is connected to the three-way stopcock inlet 171, the three-way stopcock hot brine outlet 172 is connected to the upper inlet 131 of the hot brine tank through a pipeline, the lower outlet 132 of the hot brine tank is connected to the hot brine side inlet 141 of the heat exchanger, the lower inlet 133 of the hot brine tank is connected to the hot brine side outlet 142 of the heat exchanger, the fresh water side inlet 143 of the heat exchanger is connected to the upper outlet 152 of the fresh water tank, and the fresh water side outlet 144 of the heat exchanger is connected to the upper inlet 153 of the fresh water tank.

[0057] The lithium solution concentration unit on the right side includes a booster pump 18, a nanofiltration membrane device 19, a second evaporator 20, a first evaporator 28, a lithium carbonate precipitation device 27, a three-way stopcock II 26 and a magnesium solution tank 25; the magnesium-lithium solution outlet 173 of the three-way stopcock is connected to the nanofiltration membrane device inlet 191 through the booster pump 18, the nanofiltration membrane device outlet 192 is connected to the second evaporator 20 through a pipeline, and the nanofiltration membrane device concentrated solution outlet 193 is connected to the magnesium solution tank 25; the first evaporator heating steam inlet 284 is connected to the first evaporator heat exchange tube bundle 287, and the first evaporator exhaust hole 288 is connected to the first evaporator secondary steam outlet 283, the second evaporator heating steam outlet 284 and the second evaporator heating steam outlet 285 in sequence through a pipeline. The hot steam inlet 203 and the second evaporator heat exchange tube bundle 207, the second evaporator concentrated liquid outlet 202 is connected to the first evaporator sprayer 286 via the first evaporator feed liquid inlet 281, the first evaporator concentrated liquid outlet 282 is connected to the lithium carbonate precipitation device 27, the second evaporator feed liquid inlet 201 is connected to the second evaporator sprayer 206, the second evaporator steam exhaust hole 208 is connected to the second evaporator secondary steam outlet 204 and the steam inlet pipe box 4 of the adsorption tower device unit in sequence through pipelines, the second evaporator condensate outlet 205 and the first evaporator condensate outlet 285 are connected to the lower inlet 155 of the fresh water tank via a three-way stopcock II 26.

[0058] Example 2 A production process for a steam condensation adsorption device for extracting lithium from plateau salt lake brine using the method of Example 1 comprises the following steps:

[0059] Step 1: Salt lake brine with a temperature of 0-5°C and a lithium ion mass concentration of 0.05% is pressurized by a salt lake water pump 1 and sequentially enters the sprayer 3 through the salt lake water inlet 21 of the four-way plug valve, the salt lake water outlet 23 of the four-way plug valve, and the sprayer water inlet 31. The salt lake brine is evenly sprayed onto the adsorption layer surface of the aluminum salt adsorbent 12 in the steam condensation adsorption tower 11 through the sprayer water outlet 32;

[0060] Step 2: Secondary steam at 55℃ enters the inlet of the first process tube bundle 5 from the steam inlet pipe box 4. 60% to 75% of the steam condenses in the first process tube bundle 5 to release the latent heat of vaporization. The condensate and uncondensed steam in the tube flow out from the outlet of the first process tube bundle 5 and enter the second process tube box 6 through the second process tube box inlet 61. The uncondensed steam enters the inlet of the second process tube bundle 8 through the second process tube box steam outlet 62. 70% to 80% of the inlet steam in the second process condenses in the second process tube bundle 8 to release the latent heat of vaporization and then flows through the third process. The process box inlet 71 enters the third process box 7. The uncondensed steam enters the third process tube bundle 9 through the third process box steam outlet 72 to continue condensing and releasing heat. The condensate in the third process tube bundle 9 enters the terminal box 10 through the terminal box inlet 101. The condensate at the bottom of the second process box 6, the third process box 7 and the terminal box 10 is collected through the second process box condensate outlet 63, the third process box condensate outlet 73 and the terminal box outlet 102 respectively. The collected condensate enters the fresh water tank 15 through the middle inlet 151 of the fresh water tank.

[0061] Step 3: The granular aluminum salt adsorbent 12 with a diameter of about 1mm in the steam condensation absorption tower 11 forms a fluidized bed structure heat exchanger with the first process tube bundle 5, the second process tube bundle 8 and the third process tube bundle 9. During the adsorption process, the salt lake brine sprayed by the sprayer 3 forms a thin liquid film on the outside of the heat exchange tube wall of the first process tube bundle 5 through the aluminum salt adsorbent 12. Under the impact of the salt lake brine, the collision between the aluminum salt adsorbent 12 and the heat exchange tube wall realizes heat exchange. The salt lake brine outside the tube bundle and the aluminum salt adsorbent 12 absorb the latent heat of vaporization released by the condensation of steam in the first process tube bundle 5, and the temperature rises to 50°C. The aluminum salt adsorbent 12 adsorbs magnesium and lithium ions in the salt lake brine; in the second process heat tube bundle 8 and the third process tube bundle 9 On the outer wall, the temperature of the aluminum salt adsorbent 12 and the salt lake brine continues to rise to 52-53°C. After the initial adsorption outside the first-process tube bundle 5, the salt lake brine with a reduced lithium ion concentration continues to undergo adsorption reaction with the aluminum salt adsorbent 12. The hot brine that has completed the adsorption process is collected at the bottom of the steam condensation absorption tower 11 and enters the hot brine tank 13 in sequence through the steam condensation absorption tower outlet 111, the three-way plug valve inlet 171, the three-way plug valve hot brine outlet 172 and the hot brine tank upper inlet 131.

[0062] Step 4: The hot brine in the hot brine tank 13 flows sequentially through the lower outlet 132 of the hot brine tank, the hot brine side inlet 141 of the heat exchanger, the heat exchanger 14, the hot brine side outlet 142 of the heat exchanger and the lower inlet 133 of the hot brine tank to form a hot brine closed circulation loop. The cold fresh water in the fresh water tank 15 flows sequentially through the upper outlet 152 of the fresh water tank, the fresh water side inlet 143 of the heat exchanger, the heat exchanger 14, the fresh water side outlet 144 of the heat exchanger and the upper inlet 153 of the fresh water tank to form a cold fresh water closed circulation loop. The hot brine in the hot brine closed circulation loop of the heat exchanger 14 heats the fresh water in the cold fresh water closed circulation loop, and the temperature of the fresh water in the fresh water tank 15 rises to 45-47°C.

[0063] Step 5: During the desorption process, preheated fresh water in the fresh water tank 15 flows out from the lower outlet 154 of the fresh water tank, and after being pressurized by the fresh water pump 16, enters the sprinkler 3 in sequence through the fresh water inlet 24 of the four-way stopcock, the salt lake water outlet 23 of the four-way stopcock, and the sprinkler inlet 31. The fresh water sprayed through the sprinkler outlet 32 ​​passes through the aluminum salt adsorbent 12 and forms a thin liquid film on the outer walls of the heat exchange tubes of the first-process tube bundle 5, the second-process tube bundle 8, and the third-process tube bundle 9. Under the impact of the fresh water, the collision between the aluminum salt adsorbent 12 and the heat exchange tube wall realizes heat exchange. The fresh water outside the tube bundle and the aluminum salt adsorbent 12 absorb the latent heat of vaporization released by the condensation of steam in the tube bundle, and the temperature rises to 50-52°C. The magnesium and lithium ions adsorbed by the aluminum salt adsorbent 12 are desorbed with the fresh water. After desorption, the magnesium and lithium solution at 50-52°C is collected at the bottom of the steam condensation adsorption tower 11.

[0064] Step 6: The magnesium-lithium solution at 50-52° C. passes through the steam condensation adsorption tower outlet 111, the three-way stopcock inlet 171, and the three-way stopcock magnesium-lithium solution outlet 173 in sequence, and after being pressurized by the booster pump 18, enters the nanofiltration membrane device 19 through the nanofiltration membrane device inlet 191 to complete the separation of magnesium ions. The lithium solution after the magnesium ions are removed is used as the feed liquid through the nanofiltration membrane device outlet 192 and the second evaporator feed liquid inlet 201 to enter the second evaporator sprayer 206. The magnesium ion-rich solution flows into the magnesium solution tank 25 through the nanofiltration membrane device concentrate outlet 193;

[0065] Step 7: The lithium solution is sprayed onto the outer surface of the second evaporator heat exchange tube bundle 20g through the second evaporator sprayer 20f. The liquid film outside the tube bundle absorbs the heat released by the condensation of the steam in the tube of the second evaporator heat exchange tube bundle 20g. The evaporated and concentrated lithium solution is collected at the bottom of the second evaporator 20 and flows into the first evaporator sprayer 286 through the second evaporator concentrated liquid outlet 202 and the first evaporator feed liquid inlet 281. The concentrated lithium solution from the first evaporator sprayer 286 is sprayed onto the outer surface of the first evaporator heat exchange tube bundle 287 to form a uniform liquid film. The liquid film outside the tube bundle absorbs the heat released by the condensation of the steam in the tube of the first evaporator heat exchange tube bundle 287. The saturated lithium solution that is further evaporated and concentrated is collected at the bottom of the first evaporator 28 and flows into the lithium carbonate precipitation device 27 through the first evaporator concentrated liquid outlet 282.

[0066] Step 8: 65℃ heating steam is used as the heat source for evaporating the concentrated lithium solution. The heating steam enters the first evaporator heat exchange tube bundle 287 through the first evaporator heating steam inlet 284 to condense and release heat. The secondary steam generated by the evaporation of the lithium solution outside the first evaporator heat exchange tube bundle 287 passes through the first evaporator exhaust hole 288 and mixes with the uncondensed steam in the first evaporator heat exchange tube bundle 287. The mixed steam enters the second evaporator heat exchange tube bundle 207 through the first evaporator secondary steam outlet 283 and the second evaporator heating steam inlet 203 as the second evaporator. The heat source of the lithium solution in the second evaporator 20; the steam generated by the evaporation of the lithium solution outside the second evaporator heat exchange tube bundle 207 is mixed with the uncondensed steam in the second evaporator heat exchange tube bundle 207 through the second evaporator exhaust hole 208, and the mixed steam enters the steam inlet pipe box 4 through the second evaporator secondary steam outlet 204, and the condensate in the second evaporator 20 and the first evaporator 28 flows out through the second evaporator condensate outlet 205 and the first evaporator condensate outlet 285 respectively, and flows into the fresh water tank 15 through the three-way stopcock II 26 and the lower inlet 155 of the fresh water tank.

[0067] Step 9: The saturated concentrated lithium solution flowing out of the concentrated liquid outlet 282 of the first evaporator is dehydrated in the lithium carbonate precipitation device 27 to obtain high-purity lithium carbonate solid.

[0068] The above technical solution is adopted to extract lithium from plateau salt lakes through a steam condensation adsorption tower device, which couples the condenser of the multi-effect evaporation system and the traditional adsorption tower into one, and has both steam condensation and lithium adsorption functions. The heat exchange efficiency is improved by the collision between the aluminum salt adsorbent and the salt lake brine and the tube bundle. In the three-process tube bundle of the steam condensation adsorption tower, the heat released by the condensation of the 55°C secondary steam generated in the second evaporator is used to heat the aluminum salt adsorbent outside the tube bundle and the sprayed salt lake brine to 52-53°C, reaching the optimal adsorption temperature for the lithium adsorption process of the salt lake brine, thereby improving the overall adsorption efficiency in the adsorption tower. The added brine after adsorption is preheated through a heat exchanger to preheat the fresh water required for the subsequent desorption process. After heating, the fresh water is used to leach the adsorbent saturated with adsorption to complete the desorption process, saving the amount of heating steam in the three-process tube bundle and reducing the energy consumption cost of lithium extraction from salt lakes. The heat exchange tube bundle is arranged in three processes to optimize the temperature of the adsorbent and salt lake brine at different positions in the adsorption tower, that is, the temperature of the adsorbent and salt lake brine gradually increases from top to bottom in the adsorption tower, corresponding to the decrease in the lithium concentration of the salt lake brine from top to bottom in the adsorption tower. The adsorption rate of lithium in the salt lake brine is enhanced by increasing the temperature of the adsorbent and salt lake brine at the bottom of the adsorption tower.

Claims

1. A steam condensation adsorption device for extracting lithium from salt lake brine, characterized by: It includes an adsorption tower unit and a lithium solution concentration unit. The adsorption tower unit includes a salt lake water pump, a four-way plug valve, a steam condensation adsorption tower, a hot brine tank, a heat exchanger, a fresh water tank, a fresh water pump and a three-way plug valve; the steam condensation adsorption tower includes a sprayer, several process tube bundles, and each process tube bundle is provided with a pipe box, a terminal condensation water tank and an adsorbent; the salt lake water pump is connected to the four-way plug valve, and the fresh water tank is also connected to the four-way plug valve through the fresh water pump. The four-way plug valve guides the fresh water and salt water into the sprayer; the steam condensation adsorption tower is connected to the lithium solution concentration unit through a steam pipeline, several The stage tube bundle is connected to the pipe box and then to the terminal condensate water tank. Multiple pipe boxes and the terminal condensate water tank are connected to the fresh water tank. The outlet of the steam condensation adsorption tower is connected to the three-way plug valve, which is also connected to the hot brine tank. The hot brine tank is connected to the heat exchanger, and the heat exchanger is also connected to the fresh water tank. The lithium solution concentration unit includes a booster pump, a nanofiltration membrane device, a two-stage evaporator, a lithium carbonate precipitation device, a three-way plug valve and a magnesium solution tank. The three-way plug valve is connected to the booster pump, the booster pump is connected to the nanofiltration membrane device, the nanofiltration membrane device is connected to the second evaporator through a pipeline, and the nanofiltration membrane device is also connected to the magnesium solution tank.

2. The steam condensation adsorption device for extracting lithium from salt lake brine according to claim 1, characterized in that: A first evaporator heat exchange tube bundle is arranged in the first evaporator, the first evaporator steam exhaust hole is connected to the first evaporator secondary steam outlet, the second evaporator heating steam inlet and the second evaporator heat exchange tube bundle through a pipeline, the second evaporator concentrated liquid outlet is connected to the first evaporator sprayer through the first evaporator feed liquid inlet, the first evaporator concentrated liquid outlet is connected to the lithium carbonate precipitation device, the second evaporator feed liquid inlet is connected to the second evaporator sprayer, the second evaporator steam exhaust hole is connected to the second evaporator secondary steam outlet and the steam inlet pipe box of the adsorption tower device in sequence through a pipeline, the second evaporator condensate outlet and the first evaporator condensate outlet are connected to the lower inlet of the fresh water tank through a three-way stopcock.

3. A production process for extracting lithium from salt lake brine, using the steam condensation adsorption device for extracting lithium from salt lake brine according to claim 2, characterized in that: The steps include: Step 1: The salt lake brine is pressurized by the salt lake water pump and enters the sprayer through the four-way plug valve. The salt lake brine is sprayed onto the surface of the adsorbent in the steam condensation adsorption tower through the sprayer; Step 2: Constant-temperature steam enters several process tube bundles and pipe boxes in series step by step; the condensate in the process tube bundle at the end enters the end pipe box through the end condensate tank; the outlets of each pipe box and the end pipe box are collected, and the collected condensate enters the fresh water tank; Step 3: The aluminum salt adsorbent in the steam condensation absorption tower and several process tube bundles form a fluidized bed heat exchanger. During the adsorption process, the salt lake brine sprayed by the sprayer sequentially impacts the several process tube bundles, and the aluminum salt adsorbent exchanges heat with the impacted process tube bundles, and the aluminum salt adsorbent adsorbs magnesium and lithium ions in the salt lake brine. The hot brine that has completed the adsorption process is collected at the bottom of the steam condensation absorption tower and enters the hot brine tank through a three-way stopcock. Step 4: The hot brine in the hot brine tank forms a hot brine closed circulation loop between the hot brine tank and the heat exchanger, and the cold fresh water in the fresh water tank forms a cold fresh water closed circulation loop between the fresh water tank and the heat exchanger; the hot brine in the hot brine closed circulation loop of the heat exchanger heats the fresh water in the cold fresh water closed circulation loop, and the fresh water temperature rises to 45-47°C; Step 5: During the desorption process, the preheated fresh water in the fresh water tank is pressurized by the fresh water pump and then enters the sprayer through a four-way stopcock valve. The sprayed fresh water and aluminum salt adsorbent form a thin liquid film on the outside of the heat exchange tube walls of several process tube bundles. Under the impact of the fresh water, the collision between the aluminum salt adsorbent and the heat exchange tube wall realizes heat exchange. The fresh water and aluminum salt adsorbent outside the tube bundle absorb the latent heat of vaporization released by the condensation of steam in the tube bundle, and the temperature rises to 50-52°C. The magnesium and lithium ions adsorbed by the aluminum salt adsorbent are desorbed from the fresh water. After desorption, the magnesium and lithium solution at 50-52°C is collected at the bottom of the steam condensation adsorption tower. Step 6: The magnesium and lithium solutions at 50-52° C. sequentially pass through the outlet of the steam condensation adsorption tower into the three-way stopcock, are pressurized by the booster pump, and enter the nanofiltration membrane device to complete the separation of magnesium ions. The lithium solution after the magnesium ions are removed is used as the feed liquid and passes through the nanofiltration membrane device and the second evaporator. The solution rich in magnesium ions flows into the magnesium solution tank through the concentrated solution outlet of the nanofiltration membrane device; Step 7: The lithium solution is sprayed onto the outer surface of the second evaporator heat exchange tube bundle, and the liquid film outside the tube bundle absorbs the heat released by the condensation of steam in the tubes of the second evaporator heat exchange tube bundle; the evaporated and concentrated lithium solution is collected at the bottom of the second evaporator, flows into the first evaporator sprayer through the second evaporator, and the concentrated lithium solution from the first evaporator sprayer is sprayed onto the outer surface of the first evaporator heat exchange tube bundle to form a uniform liquid film. The liquid film outside the tube bundle absorbs the heat released by the condensation of steam in the tubes of the first evaporator heat exchange tube bundle. The further evaporated and concentrated saturated lithium solution is collected at the bottom of the first evaporator and flows into the lithium carbonate precipitation device; Step 8: 65° C. heating steam is used as a heat source for evaporating and concentrating the lithium solution. The heating steam enters the first evaporator heat exchange tube bundle through the first evaporator to condense and release heat. Steam generated by evaporation of the lithium solution outside the first evaporator heat exchange tube bundle mixes with the uncondensed steam in the first evaporator heat exchange tube bundle through the first evaporator exhaust port. The mixed steam enters the second evaporator heat exchange tube bundle through the first evaporator secondary steam outlet and the second evaporator heating steam inlet, serving as a heat source for evaporating the lithium solution in the second evaporator. Steam generated by evaporation of the lithium solution outside the second evaporator heat exchange tube bundle mixes with the uncondensed steam in the second evaporator heat exchange tube bundle through the second evaporator exhaust port. The mixed steam enters the steam inlet pipe box through the second evaporator secondary steam outlet. Condensate in the second evaporator and the first evaporator respectively flows into the fresh water tank through three-way stopcocks. Step 9: The saturated concentrated lithium solution flowing out of the first evaporator is dehydrated in a lithium carbonate precipitation device to obtain high-purity lithium carbonate solid.

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