Lithium-rich liquid treatment system

Abstract

The utility model relates to the technical field of efficient utilization of lithium resources, in particular to a lithium-rich liquid treatment system. The lithium-rich liquid treatment system comprises a lithium precipitation mother liquid treatment unit, a bipolar membrane acid-base preparation unit and a sodium carbonate preparation unit which are connected in sequence; and an outlet of the sodium carbonate preparation unit is communicated with a feeding hole of the lithium precipitation mother liquor treatment unit. According to the utility model, the lithium-rich liquid is firstly subjected to lithium precipitation, the lithium precipitation mother liquor is neutralized, and the bipolar membrane acid-base preparation process is organically combined, so that on one hand, the treatment cost of bipolar membrane raw materials is reduced, and on the other hand, the acid generated by the bipolar membrane is returned to the neutralizing tank to be neutralized with the lithium precipitation mother liquor; alkali is sent to a CO2 absorption device to be used for absorbing CO2 to prepare a carbonate solution; the carbonate solution is sent to a sodium carbonate preparation device to generate sodium carbonate and is sent to a lithium precipitation reaction kettle for lithium precipitation. And the produced substances are recycled, so that the production cost of the system and the treatment cost of the lithium-rich liquid are greatly reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of efficient utilization of lithium resources, and particularly relates to a treatment system for lithium-rich liquid. Background Art

[0002] According to different raw materials, the lithium extraction process can be divided into two process routes: lithium extraction from ore and lithium extraction from brine. The lithium extraction from ore is the earliest adopted process route. Due to the relatively small total lithium reserves in ore, high energy consumption, and the depletion of high-quality resources after hundreds of years of mining, the production cost is relatively high. While the lithium resources in salt lake brine account for 71% of China's lithium resource reserves, and the process of lithium extraction from brine is relatively simple and the cost is relatively low. Therefore, lithium extraction from brine has become the mainstream research process.

[0003] In the process of producing lithium carbonate products by the adsorption method, since the solubility of lithium carbonate is 1.01g / 100gH2O (60°C), 0.72g / 100gH2O (80°C), the lithium ion concentration in the mother liquor of lithium precipitation generated in the lithium precipitation step is about 1.0 - 2.5g / L, which is a multi-component complex brine system, and also contains a large amount of sodium ions (40 - 65g / L), carbonate ions (10 - 30g / L), and impurity ions such as sulfate or chloride ions.

[0004] If the mother liquor of lithium precipitation is recycled back to the system, it will cause the enrichment of impurity ions in the system, and discharging it will result in a large amount of waste of lithium ions. Traditional methods for treating the mother liquor of lithium precipitation include acidification, causticization followed by evaporation to remove sodium, freezing nitre followed by evaporation to remove sodium, evaporation to remove sodium followed by freezing nitre, and introducing phosphate radicals to prepare lithium phosphate, etc. However, all of them have relatively high costs and cannot effectively recover useful resources. Content of the Utility Model

[0005] The purpose of the utility model is to provide a treatment system for lithium-rich liquid with low production cost.

[0006] In order to achieve the above purpose, the technical solution of the utility model is as follows:

[0007] A treatment system for lithium-rich liquid includes a mother liquor of lithium precipitation treatment unit, a bipolar membrane for preparing acid and alkali unit, and a soda ash preparation unit connected in sequence; the outlet of the soda ash preparation unit is communicated with the feed inlet of the mother liquor of lithium precipitation treatment unit.

[0008] In one of the preferred embodiments, the mother liquor of lithium precipitation treatment unit includes a lithium precipitation reaction kettle, a lithium precipitation slurry pump, a filter press, a neutralization tank, and a neutralization pump connected in sequence.

[0009] In one of the preferred embodiments, the soda ash preparation unit includes a CO2 absorption device and a soda ash preparation device.

[0010] In one preferred embodiment, the bipolar membrane acid and alkali production unit includes a bipolar membrane device.

[0011] In one preferred embodiment, the lithium-rich liquid treatment system includes a lithium precipitation reactor, a lithium precipitation slurry pump, a filter press, a neutralization tank, a neutralization pump, a bipolar membrane device, a CO2 absorption device, and a soda ash preparation device connected in sequence; the outlet of the soda ash preparation device is communicated with the inlet of the lithium precipitation reactor; the acid outlet of the bipolar membrane device is communicated with the inlet of the neutralization tank, and the alkali outlet of the bipolar membrane device is communicated with the inlet of the CO2 absorption device.

[0012] The lithium-rich liquid is obtained through the adsorption process of high-lithium-concentration brine. The lithium-rich liquid is first subjected to lithium precipitation, and the lithium precipitation mother liquor is obtained after filtering the lithium precipitation cake; the lithium precipitation mother liquor is neutralized to produce a neutralization mother liquor; the neutralization mother liquor is used for bipolar membrane acid and alkali production, the acid returns to the neutralization tank to neutralize the lithium precipitation mother liquor, and the alkali is sent to the CO2 absorption device to absorb CO2 to prepare a carbonate solution; the carbonate solution is sent to the soda ash preparation device for treatment to obtain a sodium carbonate mixed solution; the sodium carbonate mixed solution is sent to the lithium precipitation reactor for lithium precipitation.

[0013] Since the neutralization mother liquor basically does not contain solid insoluble substances and calcium and magnesium ions, the salt dissolution can save the impurity removal and refining process and can be directly used as the raw material for bipolar membrane acid and alkali production. The main cations are Na + , and the main anions are Cl - , and a small amount of K + , Li + will also enter the dilute alkali, which will not affect the bipolar membrane process, and is especially suitable for remote areas where acids and alkalis are difficult to obtain. The dilute acid produced by the bipolar membrane is directly returned to the lithium precipitation mother liquor to adjust the acid, and the dilute alkali solution is directly used for CO2 absorption and recycled within the system, greatly reducing the material cost.

[0014] In one preferred embodiment, the gas outlet of the neutralization tank is communicated with the inlet of the CO2 absorption device.

[0015] CO2 is generated during the neutralization of the lithium precipitation mother liquor; the CO2 is sent to the CO2 absorption device to prepare a carbonate solution.

[0016] In one preferred embodiment, the outlet of the neutralization pump is also communicated with the concentration evaporation recovery system.

[0017] A part of the neutralization mother liquor generated in the neutralization tank is sent to the evaporation system through the neutralization pump to evaporate and recycle the neutralization mother liquor.

[0018] In one preferred embodiment, the lithium-rich liquid treatment system further includes a slurry washing filtrate recovery unit, and the slurry washing filtrate recovery unit is respectively communicated with the lithium precipitation mother liquor treatment unit and the soda ash preparation unit.

[0019] In one preferred embodiment, the sizing filtrate recovery unit includes a sizing tank, a sizing pump, and a centrifuge that are connected in sequence.

[0020] In one preferred embodiment, the filter press is connected to the sizing tank, the sizing pump, the centrifuge, and the soda ash preparation device in sequence, and the solid phase outlet of the filter press is connected to the sizing tank.

[0021] The lithium-rich solution is subjected to lithium precipitation and filtration to obtain a lithium precipitation cake and a lithium precipitation mother liquor; the lithium precipitation cake is sized with pure water and then centrifuged to obtain lithium carbonate and sizing filtrate. The main component of the sizing filtrate is a sodium carbonate mixed solution, and the sizing filtrate is transported to the soda ash preparation device for soda ash preparation, effectively reducing the dosage of sodium carbonate reagent and production cost.

[0022] In one preferred embodiment, the solid phase outlet of the centrifuge is connected to the lithium carbonate drying system.

[0023] The lithium carbonate obtained by centrifugation is purified and then sold externally.

[0024] The beneficial effects of the present utility model are as follows:

[0025] The present utility model organically combines the processes of first performing lithium precipitation on the lithium-rich solution, neutralizing the lithium precipitation mother liquor, and producing acid and alkali using a bipolar membrane. On the one hand, it reduces the processing cost of the bipolar membrane raw materials. On the other hand, the acid generated by the bipolar membrane returns to the neutralization tank to neutralize the lithium precipitation mother liquor, and the alkali is sent to the CO2 absorption device to absorb CO2 to prepare a carbonate solution; the carbonate solution is sent to the soda ash preparation device to produce sodium carbonate, which is then sent to the lithium precipitation reactor for lithium precipitation. At the same time, the CO2 generated by the neutralization of the lithium precipitation mother liquor is sent to the CO2 absorption device to prepare a carbonate solution. On the other hand, the sizing filtrate obtained after sizing the lithium precipitation cake is also sent to the soda ash preparation device for soda ash preparation. All the produced substances are recycled, greatly reducing the production cost of the system and the processing cost of the lithium-rich solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the equipment connection diagram of the lithium-rich solution treatment system of the present utility model;

[0027] Figure 2 It is the unit connection diagram of the lithium-rich solution treatment system of the present utility model;

[0028] Figure 3 It is the process flow diagram of the lithium-rich solution treatment system of the present utility model;

[0029] Among them, S-1 is the lithium precipitation reactor, S-2 is the lithium precipitation slurry pump, S-3 is the filter press, S-7 is the neutralization tank, S-8 is the neutralization pump, S-9 is the bipolar membrane device, S-10 is the CO2 absorption device, and S-11 is the soda ash preparation device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The technical solution of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present utility model, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present utility model without creative efforts belong to the scope of protection of the present utility model.

[0031] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0032] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0033] Embodiment 1

[0034] As Figure 1 and Figure 2 shown, a treatment system for lithium-rich liquid includes a lithium precipitation mother liquor treatment unit, a bipolar membrane acid-base production unit, and a soda ash preparation unit connected in sequence; the outlet of the soda ash preparation unit is communicated with the feed inlet of the lithium precipitation mother liquor treatment unit.

[0035] Furthermore, the lithium-rich liquid treatment system includes a lithium precipitation reactor S-1, a lithium precipitation slurry pump S-2, a filter press S-3, a neutralization tank S-7, a neutralization pump S-8, a bipolar membrane device S-9, a CO2 absorption device S-10, and a soda ash preparation device S-11 connected in sequence; the outlet of the soda ash preparation device S-11 is communicated with the feed inlet of the lithium precipitation reactor S-1; the acid liquid outlet of the bipolar membrane device S-9 is communicated with the feed inlet of the neutralization tank S-7, and the alkali liquid outlet of the bipolar membrane device S-9 is communicated with the feed inlet of the CO2 absorption device S-10. The gas outlet of the neutralization tank S-7 is communicated with the inlet of the CO2 absorption device S-10. The outlet of the neutralization pump S-8 is also communicated with the concentration evaporation recovery system.

[0036] The lithium-rich liquid treatment system further includes a pulp washing filtrate recovery unit, and the pulp washing filtrate recovery unit is respectively communicated with the mother liquor treatment unit for lithium precipitation and the soda ash preparation unit.

[0037] The pulp washing filtrate recovery unit includes a pulp washing tank S-4, a pulp washing pump S-5 and a centrifuge S-6 that are connected in sequence.

[0038] The filter press S-3 is connected to the pulp washing tank S-4, the pulp washing pump S-5, the centrifuge S-6 and the soda ash preparation device S-11 in sequence, and the solid phase outlet of the filter press S-3 is communicated with the inlet of the pulp washing tank S-4. The solid phase outlet of the centrifuge S-6 is communicated with the lithium carbonate drying system.

[0039] As Figure 3 shown, the lithium-rich liquid is obtained through the adsorption process of high-lithium-concentration brine, and the adsorption process of high-lithium-concentration brine refers to the prior art CN 116855763 A or CN 116240397 A. The lithium-rich liquid first undergoes lithium precipitation in the lithium precipitation reactor S-1, and then is transported to the filter press S-3 by the lithium precipitation slurry pump S-2. After the lithium precipitation filter cake is filtered by the filter press S-3, a mother liquor for lithium precipitation and a lithium precipitation filter cake are obtained. The mother liquor for lithium precipitation undergoes neutralization in the neutralization tank S-7 to produce a neutralized mother liquor and CO2; the CO2 is sent to the CO2 absorption device S-10 for preparing a carbonate solution. The neutralized mother liquor is sent to the bipolar membrane device S-9 by the neutralization pump S-8 for bipolar membrane acid and alkali production. The acid returns to the neutralization tank S-7 to neutralize with the mother liquor for lithium precipitation, and the alkali is sent to the CO2 absorption device S-10 for absorbing CO2 to prepare a carbonate solution; the carbonate solution is sent to the soda ash preparation device S-11 for treatment to obtain a sodium carbonate mixed solution; the sodium carbonate mixed solution is sent to the lithium precipitation reactor S-1 for lithium precipitation. The lithium precipitation filter cake is washed with pure water in the pulp washing tank S-4 and then sent to the centrifuge S-6 by the pulp washing pump S-5 for centrifugation. Lithium carbonate and pulp washing filtrate are obtained by centrifugation. The main component of the pulp washing filtrate is the sodium carbonate mixed solution, and the pulp washing filtrate is transported to the soda ash preparation device S-11 for soda ash preparation, effectively reducing the dosage of sodium carbonate reagent and reducing production costs.

[0040] Since the neutralized mother liquor basically does not contain solid-phase insoluble substances and calcium and magnesium ions, the salt dissolution can save the impurity removal and refining process and can be directly used as the raw material for bipolar membrane acid and alkali production. The main cations therein are Na + , and the main anions are Cl - , with a small amount of K + , Li +It will also enter the dilute alkali without affecting the bipolar membrane process, making it particularly suitable for remote areas where acids and alkalis are difficult to obtain. The dilute acid produced by the bipolar membrane is directly returned to the lithium precipitation mother liquor for acid adjustment, and the dilute alkali solution is directly used for CO2 absorption and recycled within the system, greatly reducing the material cost. Part of the neutralization mother liquor generated in the neutralization tank is sent to the evaporation system through a neutralization pump for evaporation and reuse.

[0041] Obviously, the above embodiments are merely examples for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. The obvious changes or modifications derived therefrom still fall within the protection scope of the present invention.

Claims

1. A treatment system for a lithium-rich liquid, characterized in that, It includes a lithium precipitation mother liquor treatment unit, a bipolar membrane acid and alkali production unit, and a soda ash preparation unit connected in sequence; the outlet of the soda ash preparation unit is communicated with the feed inlet of the lithium precipitation mother liquor treatment unit.

2. The treatment system for lithium-rich liquid according to claim 1, characterized in that, The lithium precipitation mother liquor treatment unit includes a lithium precipitation reactor, a lithium precipitation slurry pump, a filter press, a neutralization tank, and a neutralization pump connected in sequence.

3. The treatment system for lithium-rich liquid according to claim 1, characterized in that, The soda ash preparation unit includes a CO2 absorption device and a soda ash preparation device; the bipolar membrane acid and alkali production unit includes a bipolar membrane device.

4. The treatment system for the lithium-rich solution according to claim 1, wherein, The lithium-rich liquid treatment system includes a lithium precipitation reactor, a lithium precipitation slurry pump, a filter press, a neutralization tank, a neutralization pump, a bipolar membrane device, a CO2 absorption device, and a soda ash preparation device connected in sequence; the outlet of the soda ash preparation device is communicated with the feed inlet of the lithium precipitation reactor; the acid liquid outlet of the bipolar membrane device is communicated with the feed inlet of the neutralization tank, and the alkali liquid outlet of the bipolar membrane device is communicated with the feed inlet of the CO2 absorption device.

5. The treatment system for the lithium-rich solution according to claim 4, wherein, The gas outlet of the neutralization tank is communicated with the inlet of the CO2 absorption device.

6. The treatment system for lithium-rich liquid according to claim 4, characterized in that, The outlet of the neutralization pump is also communicated with the concentration evaporation recovery system.

7. The treatment system for the lithium-rich liquid according to any one of claims 1-6, characterized in that, The lithium-rich liquid treatment system further includes a slurry washing filtrate recovery unit, and the slurry washing filtrate recovery unit is communicated with the lithium precipitation mother liquor treatment unit and the soda ash preparation unit respectively.

8. The treatment system for the lithium-rich liquid according to any one of claims 2, 4-6, characterized in that The filter press is communicated with a slurry washing tank, a slurry washing pump, a centrifuge, and a soda ash preparation device in sequence, and the solid phase outlet of the filter press is communicated with the slurry washing tank.

9. The treatment system for the lithium-rich solution according to claim 8, wherein, The solid phase outlet of the centrifuge is communicated with the lithium carbonate drying system.

Images