CN115490247A - Battery-grade lithium carbonate prepared by coupling film technology and method thereof - Google Patents
Battery-grade lithium carbonate prepared by coupling film technology and method thereof Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 41
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 title claims abstract description 21
- 229910052808 lithium carbonate Inorganic materials 0.000 title claims abstract description 21
- 238000005516 engineering process Methods 0.000 title claims abstract description 18
- 230000008878 coupling Effects 0.000 title abstract description 4
- 238000010168 coupling process Methods 0.000 title abstract description 4
- 238000005859 coupling reaction Methods 0.000 title abstract description 4
- 239000012528 membrane Substances 0.000 claims abstract description 90
- 238000000909 electrodialysis Methods 0.000 claims abstract description 80
- 238000001728 nano-filtration Methods 0.000 claims abstract description 77
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 68
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 67
- 239000012267 brine Substances 0.000 claims abstract description 57
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 claims abstract description 57
- 239000007788 liquid Substances 0.000 claims abstract description 39
- GCICAPWZNUIIDV-UHFFFAOYSA-N lithium magnesium Chemical compound [Li].[Mg] GCICAPWZNUIIDV-UHFFFAOYSA-N 0.000 claims abstract description 26
- 238000000605 extraction Methods 0.000 claims abstract description 21
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229910052700 potassium Inorganic materials 0.000 claims abstract description 17
- 239000011591 potassium Substances 0.000 claims abstract description 17
- 238000000926 separation method Methods 0.000 claims abstract description 17
- 239000000047 product Substances 0.000 claims abstract description 14
- 238000010612 desalination reaction Methods 0.000 claims abstract description 13
- 239000002244 precipitate Substances 0.000 claims abstract description 6
- 230000001376 precipitating effect Effects 0.000 claims abstract description 6
- 238000007865 diluting Methods 0.000 claims abstract 2
- 239000012535 impurity Substances 0.000 claims abstract 2
- 239000000243 solution Substances 0.000 claims description 70
- 238000011033 desalting Methods 0.000 claims description 41
- 238000005341 cation exchange Methods 0.000 claims description 30
- 229910001416 lithium ion Inorganic materials 0.000 claims description 20
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 15
- 229920002873 Polyethylenimine Polymers 0.000 claims description 12
- 238000010790 dilution Methods 0.000 claims description 11
- 239000012895 dilution Substances 0.000 claims description 11
- 239000002957 persistent organic pollutant Substances 0.000 claims description 9
- 239000007787 solid Substances 0.000 claims description 9
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 7
- 239000012465 retentate Substances 0.000 claims description 7
- 238000001035 drying Methods 0.000 claims description 6
- 238000005406 washing Methods 0.000 claims description 6
- 150000002500 ions Chemical class 0.000 claims description 5
- 238000000108 ultra-filtration Methods 0.000 claims description 5
- YQUVCSBJEUQKSH-UHFFFAOYSA-N 3,4-dihydroxybenzoic acid Chemical compound OC(=O)C1=CC=C(O)C(O)=C1 YQUVCSBJEUQKSH-UHFFFAOYSA-N 0.000 claims description 4
- 238000000262 chemical ionisation mass spectrometry Methods 0.000 claims description 4
- LNTHITQWFMADLM-UHFFFAOYSA-N gallic acid Chemical compound OC(=O)C1=CC(O)=C(O)C(O)=C1 LNTHITQWFMADLM-UHFFFAOYSA-N 0.000 claims description 4
- 150000008442 polyphenolic compounds Chemical class 0.000 claims description 4
- 235000013824 polyphenols Nutrition 0.000 claims description 4
- 238000010992 reflux Methods 0.000 claims description 4
- QAIPRVGONGVQAS-DUXPYHPUSA-N trans-caffeic acid Chemical compound OC(=O)\C=C\C1=CC=C(O)C(O)=C1 QAIPRVGONGVQAS-DUXPYHPUSA-N 0.000 claims description 4
- 239000012141 concentrate Substances 0.000 claims description 3
- ACEAELOMUCBPJP-UHFFFAOYSA-N (E)-3,4,5-trihydroxycinnamic acid Natural products OC(=O)C=CC1=CC(O)=C(O)C(O)=C1 ACEAELOMUCBPJP-UHFFFAOYSA-N 0.000 claims description 2
- 102000015863 Nuclear Factor 90 Proteins Human genes 0.000 claims description 2
- 108010010424 Nuclear Factor 90 Proteins Proteins 0.000 claims description 2
- 150000001408 amides Chemical class 0.000 claims description 2
- 229940074360 caffeic acid Drugs 0.000 claims description 2
- 235000004883 caffeic acid Nutrition 0.000 claims description 2
- QAIPRVGONGVQAS-UHFFFAOYSA-N cis-caffeic acid Natural products OC(=O)C=CC1=CC=C(O)C(O)=C1 QAIPRVGONGVQAS-UHFFFAOYSA-N 0.000 claims description 2
- 229940074391 gallic acid Drugs 0.000 claims description 2
- 235000004515 gallic acid Nutrition 0.000 claims description 2
- WQGWDDDVZFFDIG-UHFFFAOYSA-N pyrogallol Chemical compound OC1=CC=CC(O)=C1O WQGWDDDVZFFDIG-UHFFFAOYSA-N 0.000 claims description 2
- 238000000746 purification Methods 0.000 abstract description 13
- 230000008901 benefit Effects 0.000 abstract description 6
- 239000003795 chemical substances by application Substances 0.000 abstract 1
- 239000011777 magnesium Substances 0.000 description 22
- 230000008569 process Effects 0.000 description 21
- 239000012527 feed solution Substances 0.000 description 12
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 7
- 239000008367 deionised water Substances 0.000 description 7
- 229910021641 deionized water Inorganic materials 0.000 description 7
- 238000005265 energy consumption Methods 0.000 description 7
- 229910052749 magnesium Inorganic materials 0.000 description 7
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 4
- 239000013505 freshwater Substances 0.000 description 4
- 229910001425 magnesium ion Inorganic materials 0.000 description 4
- 238000011084 recovery Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000003204 osmotic effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000001223 reverse osmosis Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 239000002910 solid waste Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D15/00—Lithium compounds
- C01D15/08—Carbonates; Bicarbonates
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
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- Inorganic Chemistry (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The invention discloses a method for preparing battery-grade lithium carbonate by adopting a coupling membrane technology, which comprises the following steps: (1) pretreatment: diluting the salt lake potassium extraction brine, removing impurities, and adjusting the pH value; (2) nanofiltration: most of Mg in the feed liquid 2+ Is trapped, li + The magnesium-lithium separation is realized through a nanofiltration membrane; (3) first stage selective electrodialysis: mg in feed liquid 2+ Is trapped, and Li + Can enter a concentration chamber to synchronously realize the primary purification and concentration of lithium; (4) second stage selective electrodialysis: mg in feed liquid 2+ Is trapped, and Li + Can enter a concentration chamber to realize the deep purification and concentration of lithium; and (5) obtaining a product: adding Na 2 CO 3 As a precipitating agent, the precipitate is cleaned and dried to obtain Li 2 CO 3 And (5) producing the product. The invention also discloses the battery-grade lithium carbonate prepared by the method. The invention can fully utilize the advantages of nanofiltration and electrodialysis so as to synchronously realize the purification of lithium and the concentration of lithium, and the desalination chamber and the concentration are changed during the electrodialysisThe volume ratio of the chambers can accurately regulate and control the concentration multiplying power of the concentration chamber.
Description
Technical Field
The invention relates to the field of membrane separation, in particular to battery-grade lithium carbonate prepared by adopting a coupled membrane technology and a method thereof.
Background
Lithium and its compounds have many industrial applications including nuclear fusion, pharmaceutical industry, metallurgical industry, chemical industryIndustry, etc. In recent years, the development of new energy industries such as electronic products, electric automobiles, rechargeable lithium ion batteries and the like greatly increases the market demand of lithium raw materials, so that the global demand for lithium resources is increasing, and the lithium resources become important strategic resources. At present, the concentration of sub-ppm lithium ions in seawater is too low, the extraction difficulty is high, the energy consumption is high, and the method is not feasible economically. The lithium resource reserves in the salt lake brine in China are rich, and if the salt lake lithium resources are extracted efficiently, the development of new energy industry can be promoted, and the international competitiveness of lithium batteries and downstream industrial chains in China can be improved. It is worth noting that the composition of the brine of the Qinghai salt lake is complex (containing Mg) 2+ /Li + /Na + /K + /Cl - Borate, etc.), especially high mg/li ratio salt lake brines, can result in increased energy consumption for the lithium ion extraction process and limit lithium ion recovery purity. Therefore, the new process for extracting lithium with high lithium-magnesium separation selectivity, high flux and low energy consumption is established, and theoretical support is provided for extracting the lithium resource in the salt lake, so that the new process has important strategic significance on the lithium resource supply capacity, the lithium resource storage and the sustainable development in China.
In south America 'lithium triangle' (Chilean, argentina and Bolivia), 80% of lithium resource can be recovered by treating brine (0.1-10) with low Mg/Li ratio by lime-soda-evaporation process. More than 80% of lithium resources exist in the Chinese salt lake brine, and the storage capacity of lithium carbonate in the Qinghai salt lake brine is more than 1000 ten thousand tons. However, the magnesium-lithium ratio of the salt lake water in Qinghai China is as high as 40-300, and the traditional lithium extraction process of lime-soda-precipitation is not feasible in consideration of the cost of solid wastes, low efficiency, negative environmental influence and the like. The difficulty in lithium magnesium separation is: they have similar ionic radii (including the naked and hydrated states), e.g., the hydrated radii of lithium and magnesium ions are 0.38nm and 0.43nm, respectively; during nanofiltration, high magnesium ion content (above 100 g/L) leads to equipment that needs to overcome osmotic pressure differences that are much higher than the operating pressure range of conventional nanofiltration membranes. Aiming at the characteristics of high magnesium and low lithium of the Qinghai salt lake brine in China, the membrane technology shows unique advantages, and nanofiltration and electrodialysis are two most common membrane separation lithium extraction technologies at present.
At present, two key problems of extracting lithium from salt lake brine with high magnesium-lithium ratio are respectively reducing magnesium-lithium ratio and concentrating lithium (reaching 10 g/L). Currently, common nanofiltration technologies can effectively reduce the magnesium-lithium ratio, but usually require a multi-stage nanofiltration membrane process, and require an additional reverse osmosis process or an electrodialysis process to concentrate the product, which increases the equipment area and the process energy consumption. The selective electrodialysis process can be used to reduce the magnesium-lithium ratio, but high magnesium-lithium ratio and high magnesium concentration in salt lakes can reduce the service life and separation efficiency of monovalent selective membranes in the selective electrodialysis process, and the energy consumption is very high. In addition, the volume of the desalting chamber is the same as that of the concentrating chamber in the current selective electrodialysis process, so that the concentrating rate is limited, and the selective electrodialysis is only suitable for lithium-magnesium separation. In summary, nanofiltration membranes are suitable for treating high magnesium to lithium ratio salt lake water, while selective electrodialysis is more suitable for treating low magnesium to lithium ratio salt lake water.
Disclosure of Invention
In order to fully utilize the advantages of nanofiltration and selective electrodialysis, a nanofiltration process is firstly utilized to treat salt lake brine with high magnesium-lithium ratio and remove most magnesium ions to obtain nanofiltration water production with low magnesium-lithium ratio, and then the magnesium-lithium ratio is further reduced by designing the volume ratio of a desalting chamber and a concentrating chamber and utilizing the monovalent selectivity of a monovalent selective cation exchange membrane in the multistage selective electrodialysis process to realize the purification and concentration of lithium. The specific method is as follows.
A method for preparing battery-grade lithium carbonate by adopting a coupled film technology comprises the following steps:
step (1) pretreatment: injecting fresh water into the salt lake potassium extraction brine to dilute the brine, carrying out pretreatment in the early stage to remove insoluble solids and organic pollutants, and adjusting the pH value of the salt lake potassium extraction brine after dilution to obtain diluted brine serving as a nanofiltration feed liquid;
nanofiltration in step (2): diluted brine is injected into a nanofiltration membrane component with monovalent ion separation function as feed liquid, and most of Mg in the feed liquid 2+ Is trapped, li + Magnesium-lithium separation is realized through a nanofiltration membrane, nanofiltration leachate with low magnesium-lithium ratio is obtained and is used as feed liquid of a first-stage selective electrodialyzer, and nanofiltration retentate flows back to a pretreatment device and is mixed with the diluted brine in the step (1);
step (3), first stage selective electrodialysis: the nanofiltration percolate as a feed liquid enters a first-stage selective electrodialyzer, a monovalent selective cation exchange membrane is arranged between a desalting chamber and a concentrating chamber of the first-stage selective electrodialyzer, the feed liquid is injected into the desalting chamber, and Mg in the feed liquid 2+ Intercepted by a monovalent selective cation exchange membrane, li + Enabling the monovalent selective cation exchange membrane to enter a concentration chamber to obtain a first-stage selective electrodialysis concentrated solution, using the first-stage selective electrodialysis concentrated solution as a feeding solution for second-stage selective electrodialysis, synchronously realizing primary purification and concentration of lithium, and enabling a first-stage selective electrodialysis desalination solution in a desalination chamber to flow back to a pretreatment device to be mixed with the diluted brine in the step (1);
step (4) second stage selective electrodialysis: the first stage selective electrodialysis concentrated solution is used as feed solution to enter a second stage selective electrodialyzer, the structure of the second stage selective electrodialyzer is the same as that of the first stage selective electrodialyzer, the feed solution is injected into a desalting chamber, and Mg in the feed solution 2+ Trapped by monovalent selective cation exchange membranes, while Li + Enabling the second-stage selective electrodialysis concentrated solution to enter a concentration chamber through a monovalent selective cation exchange membrane to achieve deep purification and concentration of lithium, and enabling the second-stage selective electrodialysis desalted solution in a desalting chamber to flow back to a pretreatment device to be mixed with the diluted brine in the step (1);
and (5) obtaining a product: mixing Na 2 CO 3 Adding into the second stage selective electrodialysis concentrated solution, and adding Li to Li 2 CO 3 Precipitating in the form of (1), washing and drying the precipitate to obtain Li 2 CO 3 And (5) producing the product.
The process flow diagram of the invention is shown in figure 1.
During the pretreatment in the early stage in the step (1), removing insoluble solids and organic pollutants in water by using ultrafiltration and a cartridge filter, wherein the dilution multiple of the salt lake potassium extraction brine is 5-20 times, the content of lithium ions after dilution is not lower than 0.2g/L, the pH of the diluted brine is adjusted by using HCl and NaOH, and the adjusted pH is 3-10.
The nanofiltration membrane in the step (2) is an NF90, NF270, DK nanofiltration membrane or polypiperazine amide nanofiltration membrane, the magnesium-lithium ratio of the nanofiltration leachate is lower than 3:1, and the lithium concentration is higher than 0.2g/L.
And (3) the volume ratio of the desalting chamber to the concentrating chamber in the step (3) to the step (4) is 1-20. Under the ideal state of the operation process, cations in the desalting chamber can be completely transferred to the concentrating chamber, taking the ratio of the volume of the desalting chamber to the volume of the concentrating chamber as 10. The operation process is simple, and the lithium ion concentration can be realized only by controlling the volumes of the desalting chamber and the concentrating chamber.
The monovalent selective cation exchange membrane in the step (3) and the step (4) is a CSO membrane, a CIMS membrane or a polyphenol/polyethyleneimine positively charged assembled membrane, wherein the polyphenol/polyethyleneimine positively charged assembled membrane is a gallic acid/polyethyleneimine positively charged assembled membrane, pyrogallic acid/polyethyleneimine positively charged assembled membrane, caffeic acid/polyethyleneimine positively charged assembled membrane or protocatechuic acid/polyethyleneimine positively charged assembled membrane, and the electrodialysis current density is 1-20 mA-cm -2 The flow rate is adjusted to 10-100 LPH, naCl solution with the concentration of 0.1-1.0 g/L is filled in the concentration chamber, and Na is filled in the polar chamber 2 SO 4 The solution with the concentration of 10-30 g/L is used for adjusting the pH value of the desalting chamber to 3-10.
In the step (3), the purity of lithium in the first-stage selective electrodialysis concentrated solution is not lower than 87%, and the concentration of lithium is not lower than 2g/L.
In the step (4), the purity of lithium in the second-stage selective electrodialysis concentrated solution is not lower than 99%, and the concentration of lithium is not lower than 5g/L.
The conductivity of the deionized water selected in the step (5) is lower than 5us/cm, the washing and precipitation times are not lower than 3 times, and the drying temperature is 70-120 ℃.
The invention also relates to battery-grade lithium carbonate prepared by the method for preparing the battery-grade lithium carbonate by adopting the coupling film technology.
The invention has the following advantages:
1. the invention can fully utilize the advantages of nanofiltration and electrodialysis, thereby synchronously realizing the purification of lithium and the concentration of lithium.
2. The concentration multiplying power of the concentration chamber can be accurately regulated and controlled by changing the volume ratio of the desalting chamber to the concentration chamber.
3. The invention can effectively reduce the process energy consumption and the occupied area.
4. The method has simple process and easy operation, can effectively reduce the equipment use area, reduce the process energy consumption, improve the separation efficiency, can improve the service life of the membrane, and has the advantage of industrial amplification.
Drawings
FIG. 1 is a process flow diagram of the present invention;
FIG. 2 is a graph showing the relationship between the water recovery rate and the lithium ion recovery rate, and the magnesium-lithium ratio of the nanofiltration leachate and the water permeation flux in the nanofiltration process in example 1;
FIG. 3 is a graph showing the performance of the first stage selective electrodialysis separation in example 1 as a function of time;
figure 4 is a graphical representation of the performance of the second stage selective electrodialysis separation in example 1 as a function of time.
Detailed Description
The technical solutions of the present invention are further described below with reference to the following examples, but the present invention is not limited thereto, and any modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Example 1:
step (1) pretreatment: injecting fresh water into the salt lake potassium extraction brine to dilute the brine, carrying out pretreatment in the early stage to remove insoluble solids and organic pollutants, and adjusting the pH value of the salt lake potassium extraction brine after dilution to obtain diluted brine serving as a nanofiltration feed liquid; during the pretreatment in the step (1), removing insoluble solids and organic pollutants in water by using ultrafiltration and a cartridge filter, wherein the dilution multiple of the salt lake potassium extraction brine is 15 times, the content of the diluted lithium ions is 0.35g/L, the pH of the diluted brine is adjusted by using HCl and NaOH, and the adjusted pH is 8.
Nanofiltration in step (2): diluted brine is used as feed liquid to be injected into nanofiltration membrane group with monovalent ion separation functionMember, most of Mg in feed liquid 2+ Is trapped, li + And (2) separating magnesium from lithium by using a nanofiltration membrane to obtain nanofiltration leachate with low magnesium-lithium ratio, taking the nanofiltration leachate as feed liquid of the first-stage selective electrodialyzer, refluxing the nanofiltration retentate to a pretreatment device, mixing the nanofiltration retentate with the diluted brine obtained in the step (1), wherein the nanofiltration membrane is a DK nanofiltration membrane, the magnesium-lithium ratio of the nanofiltration leachate is 1:1, and the lithium concentration is 0.4g/L.
Step (3) first stage selective electrodialysis: the nanofiltration percolate as feed liquid enters a first stage selective electrodialyzer, a monovalent selective cation exchange membrane is arranged between a desalting chamber and a concentrating chamber of the first stage selective electrodialyzer, the feed liquid is injected into the desalting chamber, and Mg in the feed liquid 2+ Trapped by monovalent selective cation exchange membranes, while Li + The first-stage selective electrodialysis concentrated solution can be obtained by allowing a monovalent selective cation exchange membrane to enter a concentration chamber and be used as a feeding solution for second-stage selective electrodialysis, primary purification and concentration of lithium are synchronously realized, the first-stage selective electrodialysis desalinated solution in a desalting chamber flows back to a pretreatment device and is mixed with the diluted brine in the step (1), the volume ratio of the desalting chamber to the concentration chamber is 10 -2 The flow rate is adjusted to 60LPH, naCl solution is contained in the concentration chamber, the concentration is 0.5g/L, and Na is contained in the polar chamber 2 SO 4 And (3) adjusting the pH value of the desalting chamber to 8, wherein the concentration of the solution is 20g/L, the purity of lithium in the first-stage selective electrodialysis concentrated solution is 91.2%, and the concentration of lithium is 2.5g/L.
Step (4) second stage selective electrodialysis: the first stage selective electrodialysis concentrated solution is used as feed solution to enter a second stage selective electrodialyzer, the structure of the second stage selective electrodialyzer is the same as that of the first stage selective electrodialyzer, the feed solution is injected into a desalting chamber, and Mg in the feed solution 2+ Trapped by monovalent selective cation exchange membranes, while Li + The second-stage selective electrodialysis concentrated solution can be obtained by allowing a monovalent selective cation exchange membrane to enter a concentration chamber, the deep purification and concentration of lithium are realized, the second-stage selective electrodialysis desalted solution in a desalting chamber flows back to a pretreatment device, and the steps are carried outMixing the diluted brine in the step (1), wherein the volume ratio of the desalting chamber to the concentrating chamber is 10 -2 The flow rate is adjusted to 60LPH, naCl solution is contained in the concentration chamber, the concentration is 0.5g/L, and Na is contained in the polar chamber 2 SO 4 The concentration of the solution is 20g/L, the pH value of the desalting chamber is adjusted to be 8, the purity of lithium in the concentrated solution of the second-stage selective electrodialysis is 99.2%, and the concentration of lithium is 9.8g/L.
And (5) obtaining a product: na is mixed with 2 CO 3 Adding the lithium ion solution as a precipitant into the second-stage selective electrodialysis concentrated solution to make the lithium be Li 2 CO 3 Is precipitated, and the precipitate is repeatedly washed, filtered and dried with deionized water to obtain Li with purity higher than 99.2% 2 CO 3 The product is prepared by selecting deionized water with the conductivity of 5us/cm, washing and precipitating for 3 times and drying at 90 ℃.
Test results for example 1:
as can be seen from FIG. 2, through the nanofiltration process, the Mg/Li ratio is significantly reduced to be less than 3:1, and the recovery rate of Li can reach more than 90%. As can be seen from fig. 3, the first stage selective electrodialysis can effectively achieve the separation of lithium ions and magnesium ions, and the purity of the lithium ions is higher than 91.2%, and the lithium ions are concentrated to 2.3g/L. As can be seen from FIG. 4, the magnesium-lithium ratio can be further reduced by the second stage selective electrodialysis, the concentration of lithium ions can reach 9.8g/L, the purity of lithium ions is 99.2%, and after concentration and crystallization, the grade of battery-grade lithium carbonate can be reached.
Example 2:
(1) Pretreatment: injecting fresh water into the salt lake potassium extraction brine to dilute the salt lake potassium extraction brine, pre-treating the salt lake potassium extraction brine to remove insoluble solids and organic pollutants, and adjusting the pH value of the salt lake potassium extraction brine after dilution to obtain diluted brine serving as a nanofiltration feed liquid; during the pretreatment in the step (1), removing insoluble solids and organic pollutants in water by using ultrafiltration and a cartridge filter, wherein the dilution multiple of the salt lake potassium extraction brine is 10 times, the content of the diluted lithium ions is 0.53g/L, the pH of the diluted brine is adjusted by using HCl and NaOH, and the adjusted pH is 6.
(2) And (4) nanofiltration: diluted brine is injected into a nanofiltration membrane component with monovalent ion separation function as feed liquid, and most of Mg in the feed liquid 2+ Is trapped, li + And (2) separating magnesium and lithium by using a nanofiltration membrane to obtain nanofiltration leachate with low magnesium-lithium ratio, taking the nanofiltration leachate as feed liquid of the first-stage selective electrodialyzer, refluxing nanofiltration retentate to the pretreatment device, mixing the nanofiltration retentate with the diluted brine obtained in the step (1), wherein the nanofiltration membrane is a DK nanofiltration membrane, the magnesium-lithium ratio of the nanofiltration leachate is 2:1, and the lithium concentration is 0.6g/L.
(3) First-stage selective electrodialysis: the nanofiltration percolate as a feed liquid enters a first-stage selective electrodialyzer, a monovalent selective cation exchange membrane is arranged between a desalting chamber and a concentrating chamber of the first-stage selective electrodialyzer, the feed liquid is injected into the desalting chamber, and Mg in the feed liquid 2+ Trapped by monovalent selective cation exchange membranes, while Li + The first-stage selective electrodialysis concentrated solution can be obtained by allowing a monovalent selective cation exchange membrane to enter a concentration chamber and be used as a feeding solution for second-stage selective electrodialysis, primary purification and concentration of lithium are synchronously realized, the first-stage selective electrodialysis desalted solution in a desalting chamber flows back to a pretreatment device and is mixed with the diluted brine in the step (1), the volume ratio of the desalting chamber to the concentration chamber is 5:1, the monovalent selective cation exchange membrane is a CIMS membrane, and the electrodialysis current density is 5 mA-cm -2 The flow rate is adjusted to 80LPH, naCl solution is contained in the concentration chamber, the concentration is 0.5g/L, and Na is contained in the polar chamber 2 SO 4 And (3) adjusting the pH value of the desalting chamber to 8 by using the solution with the concentration of 20g/L, wherein the purity of lithium in the first-stage selective electrodialysis concentrated solution is 87.8%, and the concentration of lithium is 2.1g/L.
(4) Second stage selective electrodialysis: the first stage selective electrodialysis concentrated solution is used as feed solution to enter a second stage selective electrodialyzer, the structure of the second stage selective electrodialyzer is the same as that of the first stage selective electrodialyzer, the feed solution is injected into a desalting chamber, and Mg in the feed solution 2+ Is trapped by a monovalent selective cation exchange membrane, while Li + The second stage selective electrodialysis concentrated solution can be obtained by entering a concentration chamber through a monovalent selective cation exchange membraneAnd (2) realizing deep purification and concentration of lithium, wherein a second-stage selective electrodialysis desalination solution in a desalination chamber flows back to a pretreatment device to be mixed with the diluted brine in the step (1), the volume ratio of the desalination chamber to the concentration chamber is 5:1, a monovalent selective cation exchange membrane is a CIMS membrane, and the electrodialysis current density is 5 mA-cm -2 The flow rate is adjusted to 80LPH, naCl solution is contained in the concentration chamber, the concentration is 0.5g/L, and Na is contained in the polar chamber 2 SO 4 And (3) adjusting the pH value of the desalting chamber to 8 by using the solution with the concentration of 20g/L, wherein the purity of lithium in the concentrated solution of the second-stage selective electrodialysis is 99.1%, and the concentration of lithium is 5.3g/L.
(5) Obtaining a product: na is mixed with 2 CO 3 Adding the lithium ion solution as a precipitant into the second-stage selective electrodialysis concentrated solution to make the lithium be Li 2 CO 3 Is precipitated out, and the precipitate is repeatedly washed, filtered and dried by deionized water to obtain Li with the purity of 99.1 percent 2 CO 3 The product is prepared by selecting deionized water with the conductivity of 5us/cm, washing and precipitating for 3 times and drying at 100 ℃.
Example 3:
(1) Pretreatment: injecting fresh water into the salt lake potassium extraction brine to dilute the brine, carrying out pretreatment in the early stage to remove insoluble solids and organic pollutants, and adjusting the pH value of the salt lake potassium extraction brine after dilution to obtain diluted brine serving as a nanofiltration feed liquid; during the pretreatment in the step (1), removing insoluble solids and organic pollutants in water by using ultrafiltration and a cartridge filter, wherein the dilution multiple of the salt lake potassium extraction brine is 20 times, the content of the diluted lithium ions is 0.26g/L, the pH of the diluted brine is adjusted by using HCl and NaOH, and the adjusted pH is 6.
(2) And (4) nanofiltration: diluted brine is injected into a nanofiltration membrane component with monovalent ion separation function as feed liquid, and most of Mg in the feed liquid 2+ Is trapped, li + Separating magnesium and lithium by a nanofiltration membrane to obtain nanofiltration leachate with low magnesium-lithium ratio, taking the nanofiltration leachate as feed liquid of a first-stage selective electrodialyzer, refluxing nanofiltration raffinate to a pretreatment device, mixing the nanofiltration retentate with the diluted brine in the step (1), wherein the nanofiltration membrane is a DK nanofiltration membrane, the magnesium-lithium ratio of the nanofiltration leachate is 1:1, and lithium is obtainedThe concentration was 0.26g/L.
(3) First-stage selective electrodialysis: the nanofiltration percolate as a feed liquid enters a first-stage selective electrodialyzer, a monovalent selective cation exchange membrane is arranged between a desalting chamber and a concentrating chamber of the first-stage selective electrodialyzer, the feed liquid is injected into the desalting chamber, and Mg in the feed liquid 2+ Is trapped by a monovalent selective cation exchange membrane, while Li + The first-stage selective electrodialysis concentrated solution can be obtained by allowing a monovalent selective cation exchange membrane to enter a concentration chamber and be used as a feeding solution for second-stage selective electrodialysis, primary purification and concentration of lithium are synchronously achieved, the first-stage selective electrodialysis desalinated solution in a desalination chamber flows back to a pretreatment device and is mixed with diluted brine in the step (1), the volume ratio of the desalination chamber to the concentration chamber is 20 -2 The flow rate is adjusted to 100LPH, naCl solution is contained in the concentration chamber, the concentration is 0.5g/L, and Na is contained in the polar chamber 2 SO 4 And (3) adjusting the pH value of the desalting chamber to 8, wherein the concentration of the solution is 20g/L, the purity of lithium in the first-stage selective electrodialysis concentrated solution is 90.2%, and the concentration of lithium is 3.7g/L.
(4) Second-stage selective electrodialysis: the first stage selective electrodialysis concentrated solution is used as feed solution to enter a second stage selective electrodialyzer, the structure of the second stage selective electrodialyzer is the same as that of the first stage selective electrodialyzer, the feed solution is injected into a desalting chamber, and Mg in the feed solution 2+ Is trapped by a monovalent selective cation exchange membrane, while Li + The second-stage selective electrodialysis concentrated solution can be obtained by allowing a monovalent selective cation exchange membrane to enter a concentration chamber, deep purification and concentration of lithium are achieved, the second-stage selective electrodialysis desalinated solution in a desalting chamber flows back to a pretreatment device and is mixed with the diluted brine in the step (1), the volume ratio of the desalting chamber to the concentration chamber is 20 -2 The flow rate is adjusted to 100LPH, naCl solution is contained in the concentration chamber, the concentration is 0.5g/L, and Na is contained in the polar chamber 2 SO 4 And (3) adjusting the pH value of the desalting chamber to 8 by using the solution with the concentration of 20g/L, wherein the purity of lithium in the concentrated solution of the second-stage selective electrodialysis is 99.4%, and the concentration of lithium is 13.2g/L.
(5) Obtaining a product: mixing Na 2 CO 3 Adding the lithium ion solution as a precipitant into the second-stage selective electrodialysis concentrated solution to make the lithium be Li 2 CO 3 Is precipitated, and the precipitate is repeatedly washed with deionized water, filtered and dried to obtain Li with a purity of 99.4% 2 CO 3 The product is prepared by selecting deionized water with the conductivity of 5us/cm, washing and precipitating for 3 times, and drying at 110 ℃.
Claims (10)
1. A method for preparing battery-grade lithium carbonate by adopting a coupled film technology comprises the following steps:
step (1) pretreatment: diluting the salt lake potassium extraction brine, removing impurities, and adjusting the pH value to obtain a feed liquid for nanofiltration;
nanofiltration in step (2): diluted brine is injected into a nanofiltration membrane component with monovalent ion separation function as feed liquid, and Mg in the feed liquid 2+ Is trapped, li + Obtaining nanofiltration leachate with low magnesium-lithium ratio through a nanofiltration membrane, taking the nanofiltration leachate as feed liquid of a first-stage selective electrodialyzer, and refluxing nanofiltration retentate to a pretreatment device to be mixed with the diluted brine in the step (1);
step (3), first stage selective electrodialysis: the nanofiltration percolate as feed liquid enters a first-stage selective electrodialyzer, a monovalent selective cation exchange membrane is arranged between a desalting chamber and a concentrating chamber of the first-stage selective electrodialyzer, the feed liquid is injected into the desalting chamber, and Mg is added into the desalting chamber 2+ Intercepted by a monovalent selective cation exchange membrane, li + Enabling the concentrated solution to enter a concentration chamber through a monovalent selective cation exchange membrane to obtain a first-stage selective electrodialysis concentrated solution and using the concentrated solution as a feeding solution for second-stage selective electrodialysis, and enabling the first-stage selective electrodialysis desalination solution in a desalination chamber to flow back to a pretreatment device and be mixed with the diluted brine in the step (1);
step (4) second stage selective electrodialysis: the concentrated solution of the first stage selective electrodialysis enters the second stage selective electrodialysis as feed solutionThe structure of the dialyzer and the second stage selective electrodialyzer is the same as that of the first stage selective electrodialyzer, the feed liquid is injected into the desalting chamber, and Mg in the feed liquid 2+ Intercepted by a monovalent selective cation exchange membrane, li + Enabling the second-stage selective electrodialysis concentrated solution to enter a concentration chamber through a monovalent selective cation exchange membrane to obtain second-stage selective electrodialysis concentrated solution, enabling the second-stage selective electrodialysis desalination solution in a desalination chamber to flow back to a pretreatment device, and mixing the second-stage selective electrodialysis desalination solution with the diluted brine in the step (1);
and (5) obtaining a product: mixing Na 2 CO 3 Adding into the second stage selective electrodialysis concentrated solution, and adding Li to Li 2 CO 3 Precipitating in the form of (1), washing and drying the precipitate to obtain Li 2 CO 3 And (5) producing the product.
2. The method for preparing the battery-grade lithium carbonate by using the coupled membrane technology as claimed in claim 1, wherein the volume ratio of the desalting chamber to the concentrating chamber is 1-20.
3. The method for preparing battery-grade lithium carbonate by using the coupled membrane technology according to claim 1, wherein during the preliminary pretreatment in step (1), an ultrafiltration module and a cartridge filter are used for removing insoluble solids and organic pollutants in water, the dilution multiple of the salt lake potassium extraction brine is 5-20 times, the content of lithium ions after dilution is not less than 0.2g/L, and the pH of the diluted brine is adjusted by using HCl and NaOH, and the adjusted pH is 3-10.
4. The method for preparing the battery-grade lithium carbonate by using the coupled membrane technology as claimed in claim 1, wherein the nanofiltration membrane in the step (2) is a NF90 nanofiltration membrane, a NF270 nanofiltration membrane, a DK nanofiltration membrane or a polypiperazine amide nanofiltration membrane.
5. The method for preparing the battery-grade lithium carbonate by using the coupled membrane technology as claimed in claim 1, wherein the magnesium-lithium ratio of the nanofiltration leachate in the step (2) is lower than 3:1, and the lithium concentration is higher than 0.2g/L.
6. The method for preparing battery grade lithium carbonate by using the coupled membrane technology as claimed in claim 1, wherein the monovalent selective cation exchange membrane is a CSO membrane, a CIMS membrane or a polyphenol/polyethyleneimine positively charged assembled membrane.
7. The method for preparing battery grade lithium carbonate by using the coupled membrane technology according to claim 6, wherein the polyphenol/polyethyleneimine positively charged assembled membrane is a gallic acid/polyethyleneimine positively charged assembled membrane, pyrogallic acid/polyethyleneimine positively charged assembled membrane, caffeic acid/polyethyleneimine positively charged assembled membrane or protocatechuic acid/polyethyleneimine positively charged assembled membrane.
8. The method for preparing battery-grade lithium carbonate by using the coupled membrane technology as claimed in claim 1, wherein the electrodialysis current density in the steps (3) and (4) is 1-20 mA-cm -2 The flow rate is adjusted to 10-100 LPH, naCl solution with the concentration of 0.1-1.0 g/L is filled in the concentration chamber, and Na is filled in the polar chamber 2 SO 4 The solution with the concentration of 10-30 g/L is used for adjusting the pH value of the desalting chamber to 3-10.
9. The method for preparing the battery-grade lithium carbonate by adopting the coupled membrane technology as claimed in claim 1, wherein the purity of lithium in the concentrate of the first-stage selective electrodialysis in the step (3) is not lower than 87%, and the concentration of lithium is not lower than 2g/L, and the purity of lithium in the concentrate of the second-stage selective electrodialysis in the step (4) is not lower than 99%, and the concentration of lithium is not lower than 5g/L.
10. A battery grade lithium carbonate prepared by the method of preparing battery grade lithium carbonate according to any one of claims 1 to 9 using coupled film technology.
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| CN106629786A (en) * | 2016-12-08 | 2017-05-10 | 华东理工大学 | High selectivity method of extracting lithium from salt lake brine |
| CN107720785A (en) * | 2017-10-18 | 2018-02-23 | 中国科学院青海盐湖研究所 | A kind of LITHIUM BATTERY lithium hydroxide preparation method based on UF membrane coupled method |
| CN108793516A (en) * | 2018-06-25 | 2018-11-13 | 合肥科佳高分子材料科技有限公司 | A kind of method that two-stage electrodialysis concentrates hydrochloric waste water |
| CN110065958A (en) * | 2019-03-27 | 2019-07-30 | 浙江工业大学 | A kind of method that integrated selection electrodialysis and selective bipolar membrane electrodialysis treatment salt lake bittern prepare lithium hydroxide |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106629786A (en) * | 2016-12-08 | 2017-05-10 | 华东理工大学 | High selectivity method of extracting lithium from salt lake brine |
| CN107720785A (en) * | 2017-10-18 | 2018-02-23 | 中国科学院青海盐湖研究所 | A kind of LITHIUM BATTERY lithium hydroxide preparation method based on UF membrane coupled method |
| CN108793516A (en) * | 2018-06-25 | 2018-11-13 | 合肥科佳高分子材料科技有限公司 | A kind of method that two-stage electrodialysis concentrates hydrochloric waste water |
| CN110065958A (en) * | 2019-03-27 | 2019-07-30 | 浙江工业大学 | A kind of method that integrated selection electrodialysis and selective bipolar membrane electrodialysis treatment salt lake bittern prepare lithium hydroxide |
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