CN116675237A - Method for co-production of lithium potassium sodium boron by using potassium-extracted old brine and application thereof - Google Patents
Method for co-production of lithium potassium sodium boron by using potassium-extracted old brine and application thereof Download PDFInfo
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- CN116675237A CN116675237A CN202310565140.2A CN202310565140A CN116675237A CN 116675237 A CN116675237 A CN 116675237A CN 202310565140 A CN202310565140 A CN 202310565140A CN 116675237 A CN116675237 A CN 116675237A
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- nanofiltration
- potassium
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- brine
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- 239000012267 brine Substances 0.000 title claims abstract description 182
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 title claims abstract description 182
- 238000000034 method Methods 0.000 title claims abstract description 89
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 61
- ICOKRIQKVQEENK-UHFFFAOYSA-N [Na].[K].[Li].[B] Chemical compound [Na].[K].[Li].[B] ICOKRIQKVQEENK-UHFFFAOYSA-N 0.000 title claims description 4
- 238000001728 nano-filtration Methods 0.000 claims abstract description 238
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 197
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 119
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 119
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims abstract description 60
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims abstract description 60
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 claims abstract description 60
- 229910052796 boron Inorganic materials 0.000 claims abstract description 60
- 239000011591 potassium Substances 0.000 claims abstract description 60
- 229910052700 potassium Inorganic materials 0.000 claims abstract description 60
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 claims abstract description 52
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims abstract description 52
- 239000003456 ion exchange resin Substances 0.000 claims abstract description 52
- 229920003303 ion-exchange polymer Polymers 0.000 claims abstract description 52
- 239000012452 mother liquor Substances 0.000 claims abstract description 43
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 claims abstract description 40
- 229910052808 lithium carbonate Inorganic materials 0.000 claims abstract description 40
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims abstract description 38
- 239000011734 sodium Substances 0.000 claims abstract description 38
- 229910052708 sodium Inorganic materials 0.000 claims abstract description 38
- 239000000243 solution Substances 0.000 claims abstract description 36
- 239000001103 potassium chloride Substances 0.000 claims abstract description 30
- 235000011164 potassium chloride Nutrition 0.000 claims abstract description 30
- 239000007788 liquid Substances 0.000 claims abstract description 29
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 claims abstract description 28
- 239000004327 boric acid Substances 0.000 claims abstract description 28
- 238000000926 separation method Methods 0.000 claims abstract description 28
- 239000011780 sodium chloride Substances 0.000 claims abstract description 26
- 238000001704 evaporation Methods 0.000 claims abstract description 25
- 230000008014 freezing Effects 0.000 claims abstract description 24
- 238000007710 freezing Methods 0.000 claims abstract description 24
- 238000002425 crystallisation Methods 0.000 claims abstract description 23
- 230000008025 crystallization Effects 0.000 claims abstract description 23
- 238000005342 ion exchange Methods 0.000 claims abstract description 19
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims abstract description 13
- 238000001223 reverse osmosis Methods 0.000 claims abstract description 9
- 239000007787 solid Substances 0.000 claims abstract description 9
- 238000002156 mixing Methods 0.000 claims abstract description 8
- 239000010413 mother solution Substances 0.000 claims abstract description 5
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 30
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 claims description 21
- 229910001425 magnesium ion Inorganic materials 0.000 claims description 21
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 claims description 20
- 229910001424 calcium ion Inorganic materials 0.000 claims description 17
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 15
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 15
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 14
- 230000008020 evaporation Effects 0.000 claims description 14
- 125000000524 functional group Chemical group 0.000 claims description 12
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 claims description 11
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 10
- 230000001105 regulatory effect Effects 0.000 claims description 10
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 8
- 230000020477 pH reduction Effects 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 7
- 238000002360 preparation method Methods 0.000 claims description 7
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 6
- 239000002253 acid Substances 0.000 claims description 6
- 238000010992 reflux Methods 0.000 claims description 6
- PTMHPRAIXMAOOB-UHFFFAOYSA-N phosphoramidic acid Chemical group NP(O)(O)=O PTMHPRAIXMAOOB-UHFFFAOYSA-N 0.000 claims description 5
- 239000002585 base Substances 0.000 claims description 4
- 239000003513 alkali Substances 0.000 claims description 3
- NBZBKCUXIYYUSX-UHFFFAOYSA-N iminodiacetic acid Chemical compound OC(=O)CNCC(O)=O NBZBKCUXIYYUSX-UHFFFAOYSA-N 0.000 claims description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 2
- 229910052799 carbon Inorganic materials 0.000 claims description 2
- 239000013522 chelant Substances 0.000 claims description 2
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 claims description 2
- 238000000605 extraction Methods 0.000 abstract description 10
- 239000012528 membrane Substances 0.000 description 25
- 239000000203 mixture Substances 0.000 description 25
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 20
- 239000011777 magnesium Substances 0.000 description 20
- 230000000052 comparative effect Effects 0.000 description 19
- 229910052749 magnesium Inorganic materials 0.000 description 19
- 239000012535 impurity Substances 0.000 description 18
- 239000000047 product Substances 0.000 description 18
- 239000000126 substance Substances 0.000 description 16
- 150000003839 salts Chemical class 0.000 description 15
- 229910001416 lithium ion Inorganic materials 0.000 description 13
- 230000008569 process Effects 0.000 description 13
- 239000012141 concentrate Substances 0.000 description 11
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 10
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 10
- 239000011575 calcium Substances 0.000 description 10
- 238000005406 washing Methods 0.000 description 9
- GLUUGHFHXGJENI-UHFFFAOYSA-N Piperazine Chemical compound C1CNCCN1 GLUUGHFHXGJENI-UHFFFAOYSA-N 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 8
- 239000013505 freshwater Substances 0.000 description 7
- 238000004064 recycling Methods 0.000 description 7
- 239000003153 chemical reaction reagent Substances 0.000 description 6
- 238000007865 diluting Methods 0.000 description 6
- 229910001414 potassium ion Inorganic materials 0.000 description 6
- 238000001556 precipitation Methods 0.000 description 6
- 238000001953 recrystallisation Methods 0.000 description 6
- 229910001415 sodium ion Inorganic materials 0.000 description 6
- 230000004907 flux Effects 0.000 description 5
- 229910052736 halogen Inorganic materials 0.000 description 5
- 150000002367 halogens Chemical class 0.000 description 5
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 5
- 235000019341 magnesium sulphate Nutrition 0.000 description 5
- 239000011347 resin Substances 0.000 description 5
- 229920005989 resin Polymers 0.000 description 5
- 229910003251 Na K Inorganic materials 0.000 description 4
- 239000003463 adsorbent Substances 0.000 description 4
- 230000032683 aging Effects 0.000 description 4
- 229910052791 calcium Inorganic materials 0.000 description 4
- 238000001914 filtration Methods 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- GCICAPWZNUIIDV-UHFFFAOYSA-N lithium magnesium Chemical compound [Li].[Mg] GCICAPWZNUIIDV-UHFFFAOYSA-N 0.000 description 4
- 239000011259 mixed solution Substances 0.000 description 4
- 239000003960 organic solvent Substances 0.000 description 4
- 238000001179 sorption measurement Methods 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 125000004122 cyclic group Chemical group 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000003912 environmental pollution Methods 0.000 description 2
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- 241001649247 Boehmeria Species 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- -1 borate ions Chemical class 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000003337 fertilizer Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 229910017053 inorganic salt Inorganic materials 0.000 description 1
- SWHAQEYMVUEVNF-UHFFFAOYSA-N magnesium potassium Chemical compound [Mg].[K] SWHAQEYMVUEVNF-UHFFFAOYSA-N 0.000 description 1
- 238000005191 phase separation Methods 0.000 description 1
- 229940072033 potash Drugs 0.000 description 1
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 description 1
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Substances [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 1
- 235000015320 potassium carbonate Nutrition 0.000 description 1
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 1
- 229910052939 potassium sulfate Inorganic materials 0.000 description 1
- 235000011151 potassium sulphates Nutrition 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 210000004243 sweat Anatomy 0.000 description 1
- 238000000108 ultra-filtration Methods 0.000 description 1
Classifications
-
- 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
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B35/00—Boron; Compounds thereof
- C01B35/08—Compounds containing boron and nitrogen, phosphorus, oxygen, sulfur, selenium or tellurium
- C01B35/10—Compounds containing boron and oxygen
- C01B35/1045—Oxyacids
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D3/00—Halides of sodium, potassium or alkali metals in general
- C01D3/04—Chlorides
- C01D3/06—Preparation by working up brines; seawater or spent lyes
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The invention relates to the technical field of brine utilization after potassium extraction, in particular to a method for co-production of lithium, potassium, sodium and boron by using old brine after potassium extraction and application thereof. The method comprises the following steps: carrying out nanofiltration on the potassium-extracted old brine to obtain first nanofiltration produced water; the first nanofiltration product water is subjected to reverse osmosis concentration to obtain concentrated brine; the purified brine is obtained after the concentrated brine is subjected to ion exchange resin; after nanofiltration, the purified brine is respectively obtained into second nanofiltration produced water and nanofiltration concentrated water; evaporating and concentrating the second nanofiltration produced water, and then carrying out solid-liquid separation to obtain a solid and a mother liquor, the main components of which are sodium chloride; after freezing crystallization, the mother liquor is subjected to solid-liquid separation to obtain solid with main components of potassium chloride and lithium-rich mother liquor respectively; removing boron from the lithium-rich mother solution by an ion exchange method to obtain refined lithium-rich solution; mixing the refined lithium-rich solution with a carbonate solution and reacting to obtain lithium carbonate; and sequentially acidizing, freezing and crystallizing the nanofiltration concentrated water, and then carrying out solid-liquid separation to obtain boric acid. The method can realize the co-production of lithium carbonate, potassium chloride, sodium chloride and boric acid.
Description
Technical Field
The invention relates to the technical field of brine utilization after potassium extraction, in particular to a method for co-production of lithium, potassium, sodium and boron by using old brine after potassium extraction and application thereof.
Background
At present, comprehensive development and utilization of salt lake brine resources are realized by performing natural tedding and evaporative crystallization on a salt pan through a salt pan phase separation technology, and finally old brine with higher lithium enrichment degree is obtained; then decomposing and converting the potassium-magnesium mixed salt and the potassium mixed salt to prepare potassium chloride or potassium sulfate products, removing magnesium from the lithium-rich old brine by a precipitation method or an adsorption method to obtain the lithium-rich old brine with lower magnesium-lithium ratio (the mass concentration ratio of magnesium ions to lithium ions), and finally deeply removing magnesium, concentrating and precipitating lithium to obtain the industrial grade lithium carbonate products and the like.
With the progress of the scientific and technical level, new wave tide appears in the technical field of lithium extraction engineering of salt lakes. The nanofiltration separation inorganic salt technology is used as a novel membrane separation technology, ions with different valence states are separated on two sides of a pressure driven membrane through electrostatic action and a southward effect, the retention rate of high valence ions is high, and the technology is a salt lake lithium extraction technology with great industrial prospect.
In the past, old brine is treated as waste by a salt pan potash fertilizer enterprise, and the old brine is discharged to a salt lake or a salt pan to cause waste of salt lake resources, so that development of a recycling process for the old brine for extracting potassium is urgently needed.
CN103074502a discloses a salt lake brine treatment method for separating lithium from salt lake brine with high magnesium-lithium ratio, which comprises the steps of evaporating salt lake brine by a multi-stage salt pan to obtain old brine, sequentially removing sulfate radical and magnesium by a chemical method to reduce the magnesium-lithium ratio, diluting brine, separating magnesium and lithium by a nanofiltration membrane to obtain lithium-rich water with low magnesium-lithium ratio, and obtaining lithium-rich brine with the lithium ion concentration of 33-38 g/L by reverse osmosis and deep magnesium removal and evaporation in the salt pan for preparing high-purity lithium carbonate, wherein the process also has the technical defects of complex flow, high reagent consumption, high pure water consumption and the like.
CN106082284a discloses a method for producing battery-grade lithium carbonate, which uses crystallization mother liquor wastewater after producing potassium chloride by using salt lake brine as raw material, and sequentially passes through ion exchange and adsorption, ultrafiltration membrane technology, segmented nanofiltration technology, ion exchange technology, reverse osmosis technology and amplitude sun precipitation lithium to obtain battery-grade high-purity lithium carbonate, and has the technical defects of high investment cost, complex process flow and the like.
CN108275703 discloses a process for preparing lithium carbonate and potassium salt by nanofiltration water containing lithium, under the condition that the pH value of nanofiltration membrane is 4.5-5.5 when separating calcium and magnesium, the process has no interception effect on boron, and the product prepared by the method is industrial grade lithium carbonate (Li 2 CO 3 The content is more than or equal to 99.2wt percent), and the preparation of the battery grade lithium carbonate can not be realized.
CN109607578 discloses a method for extracting battery grade lithium carbonate from magnesium sulfate subtype salt lake brine, wherein the boron concentration of high lithium mother liquor produced in an MVR evaporation concentration section reaches 6.5-8.5 g/L, and the high lithium mother liquor is subjected to boron removal by an ion exchange resin tower, so that the adsorption capacity of the boron removal ion exchange resin is 1.5-1.8 mmol/mL, and the concentration of boron in the high lithium mother liquor is 1m 3 The resin can only treat 3t lithium-rich mother liquor, namely adsorption saturation, and the process has no industrial operability, and meanwhile, the salt and potassium co-production process of sodium chloride and potassium chloride is not considered.
CN104528782 discloses a method for integrally separating magnesium, lithium and boron in salt lake old brine, wherein magnesium is removed by a magnesium precipitation reagent, the concentration of magnesium ions in salt lake old brine is up to 70-120 g/L, a large amount of precipitation is generated after the magnesium precipitation reagent is used, the consumption of the reagent is extremely large, the solid-liquid separation operation is difficult to complete, and the method is not applicable to industry; meanwhile, the process uses a large amount of organic extractant, so that batch environment-friendly procedures are difficult to obtain; the method does not consider a co-production process of sodium chloride and potassium chloride.
Therefore, the research of salt lake brine at present mainly comprises the steps of directly nanofiltration separation of magnesium and preparation of lithium carbonate, and a co-production process of sodium chloride, boric acid and potassium chloride is rarely considered.
In view of this, the present invention has been made.
Disclosure of Invention
The first aim of the invention is to provide a method for co-production of lithium, potassium, sodium and boron by using potassium extracting old brine, which can realize co-production of lithium carbonate, potassium chloride, sodium chloride and boric acid.
The second purpose of the invention is to provide the application of the method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old halogen in preparation of battery-grade lithium carbonate.
In order to achieve the above object of the present invention, the following technical solutions are specifically adopted:
the invention provides a method for co-production of lithium, potassium, sodium and boron by using potassium-extracted old brine, which comprises the following steps:
(a) At least once nanofiltration is carried out on the potassium-extracted old brine to remove calcium ions, magnesium ions and sulfate ions in the potassium-extracted old brine, so as to obtain first nanofiltration produced water;
(b) Concentrating the first nanofiltration produced water by reverse osmosis to obtain concentrated brine;
(c) Adding alkali into the concentrated brine until the pH value of the concentrated brine is 7-8.5, and then removing calcium ions and magnesium ions in the concentrated brine by adopting an ion exchange method to obtain purified brine;
(d) Regulating the pH value of the purified brine to 9.3-10.5, and then carrying out nanofiltration at least once to remove HBO in the purified brine 3 2- After the nanofiltration is completed, respectively obtaining second nanofiltration produced water and nanofiltration concentrated water;
(e) Evaporating and concentrating the second nanofiltration produced water, and then carrying out solid-liquid separation to obtain a solid and a mother liquor, the main components of which are sodium chloride; the mother liquor is subjected to solid-liquid separation after freezing crystallization to respectively obtain solid with main components of potassium chloride and lithium-rich mother liquor;
(f) Removing HBO from the lithium-rich mother solution by an ion exchange method 3 2- And H 2 BO 3 - Then, refined lithium-rich liquid is obtained;
(g) Mixing and reacting the refined lithium-rich solution with a carbonate solution, and obtaining lithium carbonate after the reaction is completed;
(h) And (d) sequentially acidizing, freezing and crystallizing the nanofiltration concentrated water obtained in the step (d) and then carrying out solid-liquid separation to obtain boric acid.
The invention also provides application of the method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine in preparation of battery-grade lithium carbonate.
Compared with the prior art, the invention has the beneficial effects that:
(1) The method for co-production of lithium, potassium, sodium and boron by utilizing the potassium-extracted old brine can realize co-production of lithium carbonate, potassium chloride, sodium chloride and boric acid, and has high added value.
(2) The method for co-production of lithium, potassium, sodium and boron by utilizing the potassium-extracted old brine provided by the invention has the advantages that the impurities such as calcium, magnesium, boron, sulfate radical and the like are removed by adopting a means of combining nanofiltration and an ion exchange resin method, and the impurity removal efficiency is high.
(3) The method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine does not use an organic solvent or an adsorbent, and does not have the problems of adsorbent dissolution loss and organic solvent environmental pollution.
(4) According to the method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine, provided by the invention, only fresh water is needed to be used for brine mixing in the first production, and the fresh water generated in the subsequent production link can be recycled without replenishing fresh water.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
Fig. 1 is a process flow chart of a method for co-production of lithium, potassium, sodium and boron by using potassium-extracted old brine provided in embodiment 1 of the invention.
Detailed Description
The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and detailed description, but it will be understood by those skilled in the art that the examples described below are some, but not all, examples of the present invention, and are intended to be illustrative of the present invention only and should not be construed as limiting the scope of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
In a first aspect, the invention provides a method for co-production of lithium, potassium, sodium and boron by using potassium-extracted old brine, which can be used for co-production of lithium carbonate, potassium chloride, sodium chloride and boric acid, and comprises the following steps:
(a) And carrying out nanofiltration on the potassium-extracted old brine at least once to remove calcium ions, magnesium ions and sulfate ions in the potassium-extracted old brine, thereby obtaining first nanofiltration produced water.
In the step (a), the potassium-extracted old brine refers to waste liquid (namely tail brine after potassium extraction) generated after potassium extraction and sodium extraction of salt lake water, and the main components of the potassium-extracted old brine comprise lithium ions, potassium ions, sodium ions, calcium ions, magnesium ions, borate ions, sulfate ions and chloride ions.
The tail halogen after potassium extraction has the characteristic of low sodium and lithium enrichment, and the preparation of lithium carbonate by taking the tail halogen as a raw material has the advantages of less impurities, low difficulty, low cost and the like.
In some specific embodiments of the present invention, in step (a), the potassium extracting old brine: the concentration of magnesium ions is 80-150 g/L, the concentration of lithium ions is 0.3-5.5 g/L, the mass concentration ratio of magnesium to lithium is 50-400, the concentration of sodium ions is 1.3-9.0 g/L, the concentration of potassium ions is 0.5-4.5 g/L, the concentration of calcium ions is 1-15 g/L, and the concentration of boron elements is 1.0-2.3 g/L (all are mass concentrations).
In some embodiments of the present invention, in step (a), the nanofiltration membrane used in the nanofiltration has a membrane flux of 20 to 40LMH, which has a superior nanofiltration performance. For example, but not limited to, a roll film made of a polypiperazine material having a magnesium ion rejection rate of 95% to 99%.
In some specific embodiments of the invention, in step (a), the nanofiltration water production rate (mass ratio of produced water to raw water) is 60% to 80%.
(b) And (c) concentrating the first nanofiltration product water obtained in the step (a) by reverse osmosis (namely RO concentration) to obtain concentrated brine.
In some embodiments of the invention, in step (b), the TDS of the concentrated brine obtained after reverse osmosis concentration is increased to 60-80 g/L.
(c) Adding alkali into the concentrated brine obtained in the step (b) until the pH of the concentrated brine is 7-8.5 (including but not limited to a point value of any one of 7.2, 7.5, 7.8, 8.0 and 8.3 or a range value between any two), and then removing calcium ions and magnesium ions in the concentrated brine by adopting an ion exchange method to obtain purified brine.
(d) After the pH of the purified brine obtained in step (c) is adjusted to 9.3-10.5 (including but not limited to a point value of any one of 9.5, 9.8, 10.0 and 10.3 or a range value between any two), performing at least one nanofiltration to remove HBO in the purified brine 3 2- And after the nanofiltration is completed, respectively obtaining second nanofiltration produced water and nanofiltration concentrated water.
Wherein, nanofiltration can remove HBO 3 2- Mainly depends on the pH of the inlet water, the rejection rate of boron impurities is 0% when the pH of the inlet water is less than 7, and the rejection rate of boron impurities is 80% -90% when the pH of the inlet water is more than 9.3.
(e) And (d) evaporating and concentrating the second nanofiltration produced water, and then carrying out solid-liquid separation to obtain a solid and a mother liquor with main components of sodium chloride. And (3) carrying out solid-liquid separation on the mother liquor after freezing crystallization to obtain a solid with the main component of potassium chloride and a lithium-rich mother liquor respectively.
(f) Removing HBO from the lithium-rich mother solution obtained in the step (e) by an ion exchange method 3 2- And H 2 BO 3 - And then obtaining the refined lithium-rich liquid.
(g) And (d) mixing the refined lithium-rich solution obtained in the step (f) with a carbonate solution and reacting, and obtaining lithium carbonate after the reaction is completed. Wherein the lithium carbonate is battery grade lithium carbonate.
(h) And (d) sequentially acidizing, freezing and crystallizing the nanofiltration concentrated water obtained in the step (d), and then carrying out solid-liquid separation to obtain boric acid.
The invention uses nanofiltration means (particularly a nanofiltration roll type membrane with a substance separation function) to deeply utilize the potassium-extracted old brine, purifies the potassium-extracted old brine, removes impurities by combining nanofiltration with an ion exchange resin method, realizes the recycling of potassium, sodium, lithium and boron resources in the potassium-extracted old brine by removing calcium, magnesium and boron, realizes the co-production of lithium carbonate, potassium chloride, sodium chloride and boric acid, and has high added value.
Specifically, nanofiltration is performed in the step (a), and calcium ions, magnesium ions and sulfate ions in brine are removed by a physical separation mode of intercepting divalent ions, so that brine purification is realized.
And (d) enriching and removing boron by nanofiltration to obtain refined lithium-rich liquid and nanofiltration concentrated water (namely boron-rich brine), wherein the refined lithium-rich liquid is used for preparing battery-grade lithium carbonate, and the nanofiltration concentrated water is used for extracting boric acid.
Furthermore, the method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine does not use an organic solvent or an adsorbent, and the problems of solvent loss of the adsorbent and environmental pollution of the organic solvent are avoided.
Preferably, in the step (a), the pH of the potassium-extracted old brine is 4.5-5.5; including but not limited to a point value of any one of 4.7, 4.9, 5.0, 5.2, 5.4 or a range value therebetween.
In some specific embodiments of the present invention, in step (a), in order to ensure the operation of the nanofiltration system, the potassium-extracted old brine is subjected to brine mixing (i.e. dilution), wherein the volume ratio of the brine mixing is as follows: pure water = 1:3 to 3.6.
In some embodiments of the present invention, in the step (a), the TDS (total dissolved solid matter, meaning the concentration of total dissolved matter in water) of the potassium-extracted old brine is 110 to 130g/L.
Preferably, in the step (a), the nanofiltration pressure is 1-12 MPa; including but not limited to a point value of any one of 2MPa, 3MPa, 4MPa, 5MPa, 6MPa, 7MPa, 8MPa, 9MPa, 10MPa, 11MPa, or a range value between any two.
In some embodiments of the invention, in step (a), the nanofiltration operating pressure is a variable frequency high pressure pump.
In some embodiments of the invention, in step (a), the pressure of the nanofiltration is adjusted according to the incoming water TDS.
Preferably, in step (a), the potassium-extracted old brine is subjected to at least three nanofiltration steps, more preferably at least five nanofiltration steps.
Wherein the retention rate of the nanofiltration membrane is poor after a period of use, so that at least three nanofiltration, more preferably at least five nanofiltration, can be provided in order to ensure the impurity removal effect.
Preferably, in step (a), the nanofiltration concentrate obtained after each nanofiltration except the first nanofiltration is refluxed into the nanofiltration device.
In some embodiments of the present invention, in step (a), the nanofiltration concentrate obtained by the first nanofiltration is discharged back into the salt field.
In some specific embodiments of the present invention, in step (a), after the potassium-extracted old brine is subjected to the nanofiltration, the magnesium ion removal rate is 99.65% -99.95%, the sulfate ion removal rate is 99.0% -99.9%, and the TDS of the first nanofiltration product water is reduced to between 4 and 8 g/L.
Preferably, in step (b), after the reverse osmosis concentration, pure water is obtained at the same time as the concentrated brine, and the pure water is recycled to step (a) to dilute the potassium-extracted old brine.
Preferably, in step (c), the base comprises at least one of sodium hydroxide, potassium hydroxide and lithium hydroxide.
Preferably, in step (c), the ion exchange resin used in the ion exchange process comprises a chelating ion exchange resin.
Preferably, in step (c), the functional groups of the chelating ion exchange resin comprise iminodiacetic acid or/and aminophosphonic acid groups.
In some specific embodiments of the present invention, in the step (c), when the ion exchange method is adopted, the water inflow velocity of the concentrated brine is 10-16 BV/h, and the water inflow volume is 30-180 times of the volume of the ion exchange resin.
In some specific embodiments of the present invention, in step (c), after removing calcium and magnesium ions in the concentrated brine by the ion exchange method, the content of calcium and magnesium ions is reduced to less than 5 ppm.
Preferably, in the step (d), the nanofiltration pressure is 1-12 MPa; including but not limited to a point value of any one of 2MPa, 3MPa, 4MPa, 5MPa, 6MPa, 7MPa, 8MPa, 9MPa, 10MPa, 11MPa, or a range value between any two.
In some embodiments of the invention, in step (d), an acid or base is added to adjust the pH of the purified brine, the acid comprising hydrochloric acid; the base includes at least one of sodium hydroxide, potassium hydroxide, and lithium hydroxide.
In some embodiments of the invention, in step (d), pressure adjustment is performed according to the incoming water TDS, ensuring a recovery of 12% to 17%.
In some embodiments of the invention, in step (d), adjusting the pH may also use a boron-depleted brine.
Preferably, in step (d), the purified brine is subjected to nanofiltration at least twice.
Preferably, in the step (d), the purified brine is subjected to three nanofiltration steps, after the first nanofiltration step, nanofiltration product water X and nanofiltration concentrate water Y are respectively obtained, the nanofiltration product water X is subjected to a second nanofiltration step, second nanofiltration product water and concentrate water S are respectively obtained, and the concentrate water S is refluxed into the nanofiltration equipment; and carrying out third nanofiltration on the nanofiltration concentrated water Y to obtain nanofiltration concentrated water and produced water T respectively, and refluxing the produced water T into nanofiltration equipment.
Preferably, in the step (e), the temperature of the evaporation concentration is 80-100 ℃; including but not limited to any one of the point values or range values between any two of 82 ℃, 85 ℃, 87 ℃, 90 ℃, 95 ℃, 98 ℃.
Preferably, in the step (e), the temperature of the freeze crystallization is 10-40 ℃; including but not limited to any one of the point values or range values between any two of 15 ℃, 20 ℃, 25 ℃, 30 ℃, 35 ℃. In step (e), the temperature of the freeze crystallization is a temperature at which potassium chloride crystals precipitate, and the energy consumption is large if a subzero temperature is used, so that the temperature of the freeze crystallization (even the temperature at which potassium chloride crystals precipitate) is set to 10 to 40 ℃, preferably 10 to 30 ℃ for energy saving.
In some specific embodiments of the present application, in step (e), the method further comprises the steps of cyclic evaporation concentration and freeze crystallization of the lithium-rich mother liquor, wherein the cyclic concentration of lithium ions is 18-22 g/L or the eutectoid of lithium chloride, sodium chloride and potassium chloride occurs.
Preferably, in step (e), the condensed water produced by the evaporation concentration is recycled to step (a) to dilute the potassium-extracted old brine.
In some embodiments of the application, in step (e), the evaporative concentration is performed using an MVR evaporator or a forced circulation evaporator.
Preferably, in step (f), the ion exchange resin used in the ion exchange method comprises a chelating ion exchange resin.
Preferably, in step (f), the functional groups of the chelating ion exchange resin comprise aminopolyhydroxy groups.
Preferably, in step (g), the carbonate solution comprises a sodium carbonate solution or/and a potassium carbonate solution;
preferably, in step (g), the molar ratio of lithium element in the refined lithium-rich solution to carbon element in the carbonate solution is 2:1.1 to 1.3; including but not limited to a point value of any one of 2:1.15, 2:1.2, 2:1.25, or a range value therebetween.
Preferably, in the step (g), the temperature of the mixed material is 80-100 ℃ in the reaction process; including but not limited to any one of the point values or range values between any two of 82 ℃, 85 ℃, 87 ℃, 90 ℃, 95 ℃, 98 ℃.
In some embodiments of the invention, the carbonate solution has a mass fraction of 25% to 30%.
In some embodiments of the invention, in step (g), the reaction is completed further comprising the steps of washing, drying and grinding sequentially. Preferably, the method of washing comprises a two-stage countercurrent water washing, the temperature of the washing water used for the washing being 80-100 ℃.
Preferably, in step (h), the acid used for the acidification comprises hydrochloric acid.
Preferably, in the step (h), the acidification is to control the pH of the mixture to 1.7-1.95; including but not limited to a point value of any one of 1.75, 1.8, 1.85, 1.9 or a range value between any two.
Preferably, in step (h), the temperature of the freeze crystallization is from-10 to 5 ℃, including but not limited to a point value of any one of-8 ℃, -5 ℃, -2 ℃, 0 ℃, 2 ℃, 4 ℃ or a range value between any two; the time of the freezing crystallization is 3-5 h, including but not limited to any one of 3.5h, 4h and 4.5h or a range value between any two.
Preferably, in the step (h), the boric acid is obtained after the solid-liquid separation, and meanwhile, a boron-removed brine is obtained, and the boron-removed brine is refluxed to the step (d) for carrying out the nanofiltration.
In the invention, the pure water and condensed water in the step (b) and the step (e) can be reused for extracting the potassium old brine, adding the brine or other production water.
And in the step (d), the process water which does not enter the lower working section is returned to the upper level nanofiltration for recycling, and no wastewater is discharged, so that the yield of lithium, potassium, sodium and boron can be improved.
Therefore, the method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine provided by the invention only needs to use fresh water for brine mixing in the first production process, and in the subsequent production process, the recycled fresh water in the system can meet the production requirement (the fresh water generated in the subsequent production link can be recycled) without replenishing fresh water.
In a second aspect, the invention provides an application of the method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine in preparation of battery-grade lithium carbonate.
Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
Example 1
The potassium-extracted old brine of the embodiment is the potassium-extracted old brine of Qinghai Bohr sweat salt lake in China, and the chemical composition of the potassium-extracted old brine is shown in the following table 1.
TABLE 1 chemical composition (g/L) of Qinghai Boehmeria salt lake potassium-extracted old-fashioned acid
| B | Li | Ca | Mg | Na | K | Cl | Sulfate radical | Carbonate radical | TDS |
| 1.5 | 0.3 | 9.6 | 130 | 1.52 | 0.61 | 348 | 0.042 | 0.312 | 490 |
The method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine provided by the embodiment comprises the following steps:
(1) Adding pure water into the potassium-extracted old brine until TDS=120g/L, and separating (i.e. performing nanofiltration for 3 times) by a three-stage nanofiltration membrane under the pressure drive of a high-pressure pump to obtain lithium-containing nanofiltration produced water (1) (i.e. first nanofiltration produced water), wherein the pressure of a first-stage nanofiltration high-pressure pump is 11MPa, the pressure of a second-stage nanofiltration high-pressure pump is 2.8MPa, and the pressure of the three-stage nanofiltration high-pressure pump is 1.0MPa; the first-stage nanofiltration concentrated water is discharged back to the salt field for tedding, the second-stage nanofiltration concentrated water is returned to the first-stage nanofiltration water inlet, and the third-stage nanofiltration concentrated water is returned to the second-stage nanofiltration water inlet; the nanofiltration membrane is an organic roll membrane made of a poly piperazine material with the magnesium sulfate interception rate of 98wt%, the membrane flux is 20LMH, the nanofiltration water production rate (the mass ratio of produced water to raw water) is 60%, and the pH value of the potassium-extracted old brine is 5.5; after three-stage nanofiltration, the mass concentration ratio of magnesium and lithium in the nanofiltration water (1) containing lithium is 0.109:1, and the yields of potassium ions, sodium ions and lithium ions in the step are about 80% respectively, and the boron rejection rate is 0%.
(2) And (3) introducing the lithium-containing nanofiltration produced water (1) obtained in the step (1) into RO equipment for RO concentration to obtain RO concentrated water (1) (namely concentrated brine), wherein TDS=60 g/L. Meanwhile, pure water generated after RO concentration is recycled to the step (1) of the next working procedure for diluting and extracting potassium old brine.
(3) Purifying the RO concentrated water (1) obtained in the step (2) by using an ion exchange resin tower to remove impurities (remove calcium and magnesium), regulating the pH value of the RO concentrated water to be 8.5 by using lithium hydroxide, wherein chelating ion exchange resin is arranged in the ion exchange resin tower, the functional group of the RO concentrated water is amino phosphonic acid, the water inlet volume of the RO concentrated water (1) is 40 times of the resin volume, the water inlet flow is 10BV/h, and the contents of calcium and magnesium ions are reduced to be less than 5ppm, so that purified brine is obtained.
(4) And (3) regulating the pH value of the purified brine obtained in the step (3) to 10, and performing two-stage nanofiltration to obtain nanofiltration water yield (3) (namely second nanofiltration water yield), wherein the nanofiltration concentrated water (2) subjected to the first-stage nanofiltration is subjected to three-stage nanofiltration to obtain nanofiltration concentrated water (3). The pressure of the first-stage nanofiltration high-pressure pump is 11MPa, the pressure of the second-stage nanofiltration high-pressure pump is 2.8MPa, and the pressure of the third-stage nanofiltration high-pressure pump is 1.0MPa. The concentrated water of the second level nanofiltration returns to the water of the first level nanofiltration, and the water produced by the third level nanofiltration returns to the water of the first level nanofiltration.
(5) And (3) evaporating and concentrating the nanofiltration produced water (3) obtained in the step (4) by an evaporator, and then performing solid-liquid separation to obtain sodium chloride and mother liquor, and performing solid-liquid separation to obtain potassium chloride and lithium-rich mother liquor after freezing and crystallizing the mother liquor. Wherein the temperature of evaporation concentration is 90 ℃, and the temperature of freezing crystallization is 20 ℃. And (3) recycling condensed water generated by evaporation concentration to the step (1) of the next working procedure for diluting and extracting potassium old brine.
(6) And (3) removing boron from the lithium-rich mother liquor obtained in the step (5) through an ion exchange resin tower to obtain refined lithium-containing mother liquor (namely refined lithium-rich liquor). Wherein the ion exchange resin is a chelating ion exchange resin, and the functional group of the ion exchange resin is aminopolyhydroxy.
(7) Adding the refined lithium-containing mother liquor obtained in the step (6) into a sodium carbonate solution, wherein the mass concentration of the sodium carbonate solution is 25wt%, and the temperature of the sodium carbonate solution is 90 ℃; the ratio of carbonate ions to lithium ions in the mixed solution is 1.2:2, after uniform stirring, the mixture reacts at 90 ℃ to precipitate and crystallize, the aging time is 2 hours, then 90 ℃ hot water which is 2 times of the crystallization mass is added to carry out secondary countercurrent washing, and the mixture is dried at 110 ℃ for 3 hours, and the battery grade lithium carbonate is obtained after crushing.
(8) And (3) acidifying the nanofiltration concentrated water (3) obtained in the step (4) by hydrochloric acid (the pH of the mixture is controlled to be 1.8 in the acidification process), freezing and crystallizing (-5 ℃ for 3 hours), and filtering to obtain crude boric acid and the boron-removed brine, and refluxing the boron-removed brine to the step (4) of the next working procedure for nanofiltration.
The process flow chart of the method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine provided by the embodiment is shown in fig. 1.
The purity of the sodium chloride obtained in this example was 99.1% by weight, and the potassium chloride was K 2 The calculated content of O is 59.5 weight percent, the purity of lithium carbonate is 99.6 weight percent, and the total yield of lithium is 74.1 weight percent; the purity of boric acid was 87.1wt% and after recrystallization, it was 99.0wt%.
Example 2
The potassium-extracted old brine of the embodiment is the potassium-extracted old brine of Qinghai Da Chai Dan salt lake in China, and the chemical composition of the potassium-extracted old brine is shown in the following table 2.
TABLE 2 Qinghai Da Chai Dan chemical composition (g/L) of salt lake potassium-extracted aged halogen
| B | Li | Mg | Na | K | Cl | Sulfate radical | TDS |
| 1.66 | 2.3 | 113 | 2.08 | 1.5 | 338 | 44.9 | 490 |
The method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine provided by the embodiment comprises the following steps:
(1) Adding pure water into the potassium-extracted old brine until TDS=115 g/L, and separating by a three-stage nanofiltration membrane under the pressure drive of a high-pressure pump to obtain lithium-containing nanofiltration produced water (1), wherein the pressure of the first-stage nanofiltration high-pressure pump is 10MPa, the pressure of the second-stage nanofiltration high-pressure pump is 2.4MPa, and the pressure of the three-stage nanofiltration high-pressure pump is 1.0MPa; the first-stage nanofiltration concentrated water is discharged back to the salt field for tedding, the second-stage concentrated water is returned to the first-stage nanofiltration water inlet, and the third-stage nanofiltration concentrated water is returned to the second-stage nanofiltration water inlet; the nanofiltration membrane is an organic roll membrane made of a poly piperazine material with the magnesium sulfate interception rate of 98wt%, the membrane flux is 20LMH, the nanofiltration water production rate (the mass ratio of produced water to raw water) is 60%, and the pH value of potassium-extracted old brine is 5.3; after three-stage nanofiltration, the mass concentration ratio of magnesium to lithium in nanofiltration produced water (1) is 0.012:1, the yields of potassium ions, sodium ions and lithium ions in the step are about 80%, and the boron rejection rate is 0%.
(2) And (3) introducing the lithium-containing nanofiltration produced water (1) obtained in the step (1) into RO equipment for RO concentration to obtain RO concentrated water (1), wherein TDS=60 g/L.
(3) And (3) removing impurities from the RO concentrated water (1) obtained in the step (2) by using an ion exchange resin tower, regulating the pH value of the RO concentrated water (1) to be 7.5 by using lithium hydroxide, wherein chelating ion exchange resin is arranged in the ion exchange resin tower, the functional group of the ion exchange resin is iminodiacetic acid, the water inlet volume of the RO concentrated water (1) is 70 times of the resin volume, the water inlet flow is 13BV/h, and the contents of impurity removed calcium and magnesium ions are reduced to be less than 5ppm, so that purified brine is obtained.
(4) And (3) regulating the pH value of the purified brine obtained in the step (3) to 10, and performing two-stage nanofiltration to obtain nanofiltration product water (3), wherein the nanofiltration concentrate water (2) subjected to the first-stage nanofiltration is subjected to three-stage nanofiltration to obtain nanofiltration concentrate water (3). The pressure of the first-stage nanofiltration high-pressure pump is 12MPa, the pressure of the second-stage nanofiltration high-pressure pump is 3MPa, and the pressure of the third-stage nanofiltration high-pressure pump is 1.5MPa. The concentrated water of the second level nanofiltration returns to the water of the first level nanofiltration, and the water produced by the third level nanofiltration returns to the water of the first level nanofiltration.
(5) Evaporating and concentrating nanofiltration produced water (3) obtained in the step (4) by an evaporator, and then carrying out solid-liquid separation to obtain sodium chloride and mother liquor, and carrying out solid-liquid separation to the mother liquor after freezing and crystallizing to obtain potassium chloride and lithium-rich mother liquor. Wherein the temperature of evaporation concentration is 90 ℃, and the temperature of freezing crystallization is 20 ℃. And (3) recycling condensed water generated by evaporation concentration to the step (1) of the next working procedure for diluting and extracting potassium old brine.
(6) And (3) removing boron from the lithium-rich mother liquor obtained in the step (5) through an ion exchange resin tower to obtain refined lithium-containing mother liquor (namely refined lithium-rich liquor). Wherein the ion exchange resin is a chelating ion exchange resin, and the functional group of the ion exchange resin is aminopolyhydroxy.
(7) Adding the refined lithium-containing mother liquor obtained in the step (6) into a sodium carbonate solution, wherein the mass concentration of the sodium carbonate solution is 25wt%, and the temperature of the sodium carbonate solution is 90 ℃; the ratio of carbonate ions to lithium ions in the mixed solution is 1.2:2, after uniform stirring, the mixture reacts at 90 ℃ to precipitate and crystallize, the aging time is 2 hours, then 90 ℃ hot water which is 2 times of the crystallization mass is added to carry out secondary countercurrent washing, and the mixture is dried at 110 ℃ for 3 hours, and the battery grade lithium carbonate is obtained after crushing.
(8) And (3) acidifying the nanofiltration concentrated water (3) obtained in the step (4) by hydrochloric acid (the pH of the mixture is controlled to be 1.85 in the acidification process), freezing and crystallizing (-8 ℃ for 3 hours), and filtering to obtain crude boric acid and the boron-removed brine, and refluxing the boron-removed brine to the step (4) of the next working procedure for nanofiltration.
The purity of the sodium chloride obtained in this example was 99.3wt%, and the potassium chloride was K 2 The calculated content of O is 59.7 weight percent, the purity of lithium carbonate is 99.5 weight percent, and the total yield of lithium is 75.6 weight percent; the purity of boric acid was 87.3wt% and 99.1wt% after recrystallization.
Example 3
The potassium-extracted old brine of the embodiment is the potassium-extracted old brine of Qinghai-Dongtai Ji Naier salt lake in China, and the chemical composition of the potassium-extracted old brine is shown in the following table 3.
TABLE 3 Qinghai Dongtai Ji Naier chemical composition (g/L) of salt lake potassium-extracted old-fashioned acid
| B | Li | Mg | Na | K | Cl | Sulfate radical | TDS |
| 2.0 | 5.45 | 115 | 4.01 | 2.52 | 339 | 64 | 490 |
The method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine provided by the embodiment comprises the following steps:
(1) Adding pure water into the potassium-extracted old brine until TDS=120g/L, and separating by a three-stage nanofiltration membrane under the pressure drive of a high-pressure pump to obtain lithium-containing nanofiltration produced water (1), wherein the pressure of the first-stage nanofiltration high-pressure pump is 10MPa, the pressure of the second-stage nanofiltration high-pressure pump is 2.8MPa, and the pressure of the three-stage nanofiltration high-pressure pump is 1.0MPa; the first-stage nanofiltration concentrated water is discharged back to the salt field for tedding, the second-stage concentrated water is returned to the first-stage nanofiltration water inlet, and the third-stage nanofiltration concentrated water is returned to the second-stage nanofiltration water inlet; the nanofiltration membrane is an organic roll membrane made of a poly piperazine material with the magnesium sulfate interception rate of 98wt%, the membrane flux is 20LMH, the nanofiltration water production rate (the mass ratio of produced water to raw water) is 60%, and the pH value of potassium-extracted old brine is 5.0; after three-stage nanofiltration, the mass concentration ratio of magnesium to lithium in nanofiltration produced water (1) is 0.005:1, the yields of potassium ions, sodium ions and lithium ions in the step are about 80%, and the boron rejection rate is 0%.
(2) And (3) introducing the lithium-containing nanofiltration produced water (1) obtained in the step (1) into RO equipment for RO concentration to obtain RO concentrated water (1), wherein TDS=58 g/L.
(3) And (3) removing impurities from the RO concentrated water (1) obtained in the step (2) by using an ion exchange resin tower, regulating the pH value of the RO concentrated water (1) to be 8.0 by using lithium hydroxide, wherein chelating ion exchange resin is arranged in the ion exchange resin tower, the functional group of the ion exchange resin is aminophosphonic acid, the water inlet volume of the RO concentrated water (1) is 150 times of the resin volume, the water inlet flow is 12BV/h, and the contents of impurity removed calcium and magnesium ions are reduced to be less than 5ppm, so that purified brine is obtained.
(4) And (3) regulating the pH value of the purified brine obtained in the step (3) to 9.5, and performing two-stage nanofiltration to obtain nanofiltration product water (3), wherein the nanofiltration concentrate water (2) subjected to the first-stage nanofiltration is subjected to three-stage nanofiltration to obtain nanofiltration concentrate water (3). The pressure of the first-stage nanofiltration high-pressure pump is 12MPa, the pressure of the second-stage nanofiltration high-pressure pump is 3MPa, and the pressure of the third-stage nanofiltration high-pressure pump is 1.5MPa. The concentrated water of the second level nanofiltration returns to the water of the first level nanofiltration, and the water produced by the third level nanofiltration returns to the water of the first level nanofiltration.
(5) And (3) evaporating and concentrating the nanofiltration produced water (3) obtained in the step (4) by an evaporator, and then performing solid-liquid separation to obtain sodium chloride and mother liquor, and performing solid-liquid separation to obtain potassium chloride and lithium-rich mother liquor after freezing and crystallizing the mother liquor. Wherein the evaporating concentration temperature is 85 ℃, and the freezing crystallization temperature is 15 ℃. And (3) recycling condensed water generated by evaporation concentration to the step (1) of the next working procedure for diluting and extracting potassium old brine.
(6) Removing boron from the lithium-rich mother liquor obtained in the step (5) through an ion exchange resin tower to obtain refined lithium-containing mother liquor (namely refined lithium-rich liquor), wherein the ion exchange resin is a chelate ion exchange resin, and the functional group of the ion exchange resin is aminopolyhydroxy.
(7) Adding the refined lithium-containing mother liquor obtained in the step (6) into a sodium carbonate solution, wherein the mass concentration of the sodium carbonate solution is 26wt%, and the temperature of the sodium carbonate solution is 90 ℃; the ratio of carbonate ions to lithium ions in the mixed solution is 1.2:2, after uniform stirring, the mixture reacts at 90 ℃ to precipitate and crystallize, the aging time is 2 hours, then 90 ℃ hot water which is 2 times of the crystallization mass is added to carry out secondary countercurrent washing, and the mixture is dried at 110 ℃ for 3 hours, and the battery grade lithium carbonate is obtained after crushing.
(8) And (3) acidifying the nanofiltration concentrated water (3) obtained in the step (4) by hydrochloric acid (the pH of the mixture is controlled to be 1.9 in the acidification process), freezing and crystallizing (-10 ℃ for 3 hours), and filtering to obtain crude boric acid and the boron-removed brine, and refluxing the boron-removed brine to the step (4) of the next working procedure for nanofiltration.
The purity of the sodium chloride obtained in this example was 99.0wt%, and the potassium chloride was K 2 The calculated content of O is 59.0wt%, the purity of lithium carbonate is 99.8wt%, and the total yield of lithium is 74.5wt%; the purity of boric acid was 87.5wt% and after recrystallization, it was 99.3wt%.
Example 4
The potassium-extracted old brine of the embodiment is the potassium-extracted old brine of Qinghai West Taijialin salt lake in China, and the chemical composition of the potassium-extracted old brine is shown in the following table 4.
TABLE 4 chemical composition (g/L) of Qinghai West Ji-Neel salt lake potassium-extracted aged halogen
| B | Li | Mg | Na | K | Cl | Sulfate radical | TDS |
| 2.3 | 1.836 | 106 | 6.11 | 4.18 | 286.6 | 45.77 | 450 |
The method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine provided by the embodiment comprises the following steps:
(1) Adding pure water into the potassium-extracted old brine until TDS=115 g/L, and separating by a three-stage nanofiltration membrane under the pressure drive of a high-pressure pump to obtain lithium-containing nanofiltration produced water (1), wherein the pressure of the first-stage nanofiltration high-pressure pump is 10MPa, the pressure of the second-stage nanofiltration high-pressure pump is 2.4MPa, and the pressure of the three-stage nanofiltration high-pressure pump is 1.0MPa; the first-stage nanofiltration concentrated water is discharged back to the salt field for tedding, the second-stage concentrated water is returned to the first-stage nanofiltration water inlet, and the third-stage nanofiltration concentrated water is returned to the second-stage nanofiltration water inlet; the nanofiltration membrane is an organic roll membrane made of a poly piperazine material with the magnesium sulfate interception rate of 98wt%, the membrane flux is 20LMH, the nanofiltration water production rate (the mass ratio of produced water to raw water) is 60%, and the pH value of potassium-extracted old brine is 5.2; after three-stage nanofiltration, the mass concentration ratio of magnesium to lithium in nanofiltration produced water (1) is 0.015:1, the yields of potassium ions, sodium ions and lithium ions in the step are about 80%, and the boron rejection rate is 0%.
(2) And (3) introducing the lithium-containing nanofiltration water (1) obtained in the step (1) into RO equipment for RO concentration to obtain RO concentrated water (1), wherein TDS=60 g/L.
(3) And (3) removing impurities from the RO concentrated water (1) obtained in the step (2) by using an ion exchange resin tower, regulating the pH value of the RO concentrated water (1) to be 8.5 by using lithium hydroxide, wherein chelating ion exchange resin is arranged in the ion exchange resin tower, the functional group of the ion exchange resin is aminophosphonic acid, the water inlet volume of the RO concentrated water (1) is 80 times of the resin volume, the water inlet flow is 10BV/h, and the impurity-removed calcium and magnesium ion contents are reduced to be less than 2ppm, so that purified brine is obtained.
(4) And (3) regulating the pH value of the purified brine obtained in the step (3) to 10.5, and performing two-stage nanofiltration to obtain nanofiltration product water (3), wherein the nanofiltration concentrate water (2) subjected to the first-stage nanofiltration is subjected to three-stage nanofiltration to obtain nanofiltration concentrate water (3). The pressure of the first-stage nanofiltration high-pressure pump is 12MPa, the pressure of the second-stage nanofiltration high-pressure pump is 2MPa, and the pressure of the third-stage nanofiltration high-pressure pump is 1MPa. The concentrated water of the second level nanofiltration returns to the water of the first level nanofiltration, and the water produced by the third level nanofiltration returns to the water of the first level nanofiltration.
(5) And (3) evaporating and concentrating the nanofiltration produced water (3) obtained in the step (4) by an evaporator, and then performing solid-liquid separation to obtain sodium chloride and mother liquor, and performing solid-liquid separation to obtain potassium chloride and lithium-rich mother liquor after freezing and crystallizing the mother liquor. Wherein the temperature of evaporation concentration is 95 ℃, and the temperature of freezing crystallization is 35 ℃. And (3) recycling condensed water generated by evaporation concentration to the step (1) of the next working procedure for diluting and extracting potassium old brine.
(6) Removing boron from the lithium-rich mother liquor obtained in the step (5) through an ion exchange resin tower to obtain refined lithium-containing mother liquor (namely refined lithium-rich liquor), wherein the ion exchange resin is chelating ion exchange resin, and the functional group of the ion exchange resin is aminopolyhydroxy.
(7) Adding the refined lithium-containing mother liquor obtained in the step (6) into a sodium carbonate solution, wherein the mass concentration of the sodium carbonate solution is 27wt%, and the temperature of the sodium carbonate solution is 90 ℃; the ratio of carbonate ions to lithium ions in the mixed solution is 1.2:2, after uniform stirring, the mixture reacts at 90 ℃ to precipitate and crystallize, the aging time is 2 hours, then 90 ℃ hot water which is 2 times of the crystallization mass is added to carry out secondary countercurrent washing, and the mixture is dried at 110 ℃ for 3 hours, and the battery grade lithium carbonate is obtained after crushing.
(8) And (3) acidifying the nanofiltration concentrated water (3) obtained in the step (4) by hydrochloric acid (the pH of the mixture is controlled to be 1.75 in the acidification process), freezing and crystallizing (-2 ℃ for 4 hours), and filtering to obtain crude boric acid and the boron-removed brine, and refluxing the boron-removed brine to the step (4) of the next working procedure for nanofiltration.
The purity of the sodium chloride obtained in this example was 99.4wt%, and the potassium chloride was K 2 The calculated content of O is 59.8 weight percent, the purity of lithium carbonate is 99.7 weight percent, and the total yield of lithium is 75.7 weight percent; the purity of boric acid was 87.4wt% and after recrystallization, it was 99.2wt%.
Comparative example 1
The source and chemical composition of the potassium-extracted old brine used in this comparative example were the same as in example 1.
The method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine provided in this comparative example is basically the same as that of example 1, except that nanofiltration of step (1) and RO concentration of step (2) are not performed, but the potassium-extracted old brine is directly purified by using an ion exchange resin tower (namely, the potassium-extracted old brine is directly subjected to step (3)).
Because of the large amount of magnesium and calcium ions in the potassium-extracted old brine, the ion exchange resin tower cannot operate, and therefore, each product cannot be obtained in the comparative example 1.
As is clear from the comparison between example 1 and comparative example 1, if nanofiltration and RO concentration were not performed before ion exchange, a large amount of impurity ions in the potassium-extracted old brine would clog the ion exchange resin column, and co-production of lithium, potassium, sodium and boron could not be obtained.
Comparative example 2
The source and chemical composition of the potassium-extracted old brine used in this comparative example were the same as in example 1.
The method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine provided in this comparative example is basically the same as that of example 1, except that step (3) is not provided, that is, the pH of RO concentrated water (1) obtained in step (2) is directly adjusted to 10 and nanofiltration in step (4) is performed.
The purity of the sodium chloride obtained in this comparative example was 98.3% by weight, and the potassium chloride was K 2 The calculated content of O is 55.6 weight percent, the purity of lithium carbonate is 99.0 weight percent, and the total yield of lithium is 75.1 weight percent; the purity of boric acid is 85.1wt%, and the purity of boric acid is more than 97.2wt% after recrystallization.
The method of the comparative example not only increases the impurity content in the product, but also causes scaling, clogging, frequent chemical cleaning and low equipment operation efficiency of the nanofiltration equipment used in the step (4).
As is clear from the comparison between the example 1 and the comparative example 2, if the ion exchange method is not used to remove the calcium ions and the magnesium ions in the concentrated brine, not only the impurity content in each product is increased and improved, but also the scaling, the blockage, the frequent chemical cleaning and the low running efficiency of the nanofiltration equipment used in the step (4) are caused.
Comparative example 3
The source and chemical composition of the potassium-extracted old brine used in this comparative example were the same as in example 1.
The method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine is basically the same as that of the embodiment 1, and the difference is that the step (4) is not arranged, namely, the purified brine obtained in the step (3) is directly subjected to evaporation concentration in the step (4).
The purity of the sodium chloride obtained in this comparative example was 97.8% by weight, and the potassium chloride was K 2 The calculated content of O is 55.2 weight percent, the purity of lithium carbonate is 98.7 weight percent, and the total yield of lithium is 74.8 weight percent; boric acid product is not available.
As is clear from the comparison between example 1 and comparative example 3, boric acid could not be obtained without nanofiltration after ion exchange, and the impurity content of each of the produced products was high.
Comparative example 4
The source and chemical composition of the potassium-extracted old brine used in this comparative example were the same as in example 1.
The method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine is basically the same as that of the embodiment 1, and the difference is that the step (6) is not arranged, namely, the lithium-rich mother solution obtained in the step (5) is directly added into the sodium carbonate solution for lithium precipitation reaction.
The purity of the sodium chloride obtained in this comparative example was 99.3% by weight, and the potassium chloride was K 2 The calculated content of O is 59.5 weight percent, the purity of lithium carbonate is 95.55 weight percent, and the total yield of lithium is 75.3 weight percent; the purity of boric acid is 87.2wt%, and the purity of boric acid is more than 99.1wt% after recrystallization.
As is apparent from the comparison between example 1 and comparative example 4, if the lithium-rich mother liquor is not subjected to the ion exchange process to remove boron, the purity of lithium carbonate is significantly reduced.
In summary, the method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine provided by the invention not only can realize co-production of lithium carbonate, potassium chloride, sodium chloride and boric acid, but also has high impurity removal efficiency, and the prepared lithium carbonate, potassium chloride and sodium chloride have high purity.
While the invention has been illustrated and described with reference to specific embodiments, it is to be understood that the above embodiments are merely illustrative of the technical aspects of the invention and not restrictive thereof; those of ordinary skill in the art will appreciate that: modifications may be made to the technical solutions described in the foregoing embodiments, or equivalents may be substituted for some or all of the technical features thereof, without departing from the spirit and scope of the present invention; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions; it is therefore intended to cover in the appended claims all such alternatives and modifications as fall within the scope of the invention.
Claims (10)
1. The method for co-production of lithium, potassium, sodium and boron by using the potassium-extracted old brine is characterized by comprising the following steps:
(a) At least once nanofiltration is carried out on the potassium-extracted old brine to remove calcium ions, magnesium ions and sulfate ions in the potassium-extracted old brine, so as to obtain first nanofiltration produced water;
(b) Concentrating the first nanofiltration produced water by reverse osmosis to obtain concentrated brine;
(c) Adding alkali into the concentrated brine until the pH value of the concentrated brine is 7-8.5, and then removing calcium ions and magnesium ions in the concentrated brine by adopting an ion exchange method to obtain purified brine;
(d) Regulating the pH value of the purified brine to 9.3-10.5, and then carrying out nanofiltration at least once to remove HBO in the purified brine 3 2- After the nanofiltration is completed, respectively obtaining second nanofiltration produced water and nanofiltration concentrated water;
(e) Evaporating and concentrating the second nanofiltration produced water, and then carrying out solid-liquid separation to obtain a solid and a mother liquor, the main components of which are sodium chloride; the mother liquor is subjected to solid-liquid separation after freezing crystallization to respectively obtain solid with main components of potassium chloride and lithium-rich mother liquor;
(f) Removing HBO from the lithium-rich mother solution by an ion exchange method 3 2- And H 2 BO 3 - Then, refined lithium-rich liquid is obtained;
(g) Mixing and reacting the refined lithium-rich solution with a carbonate solution, and obtaining lithium carbonate after the reaction is completed;
(h) And (d) sequentially acidizing, freezing and crystallizing the nanofiltration concentrated water obtained in the step (d) and then carrying out solid-liquid separation to obtain boric acid.
2. The method for co-production of lithium, potassium, sodium and boron by using potassium-extracted old brine according to claim 1, wherein in the step (a), the pH of the potassium-extracted old brine is 4.5-5.5;
or/and, in the step (a), the nanofiltration pressure is 1-12 MPa;
or/and, in the step (a), the potassium-extracted old brine is subjected to nanofiltration for at least three times, more preferably at least five times;
Or/and, in the step (a), the nanofiltration concentrated water obtained after each nanofiltration except the first nanofiltration is returned into the nanofiltration equipment.
3. The method for co-production of lithium, potassium, sodium and boron by utilizing potassium-extracted old brine according to claim 1, wherein in the step (b), after the reverse osmosis concentration, pure water is obtained while concentrated brine is obtained, and the pure water is recycled to the step (a) so as to dilute the potassium-extracted old brine.
4. The method for co-production of lithium potassium sodium boron using potassium extracted old brine according to claim 1, wherein in step (c), the base comprises at least one of sodium hydroxide, potassium hydroxide and lithium hydroxide;
or/and, in the step (c), the ion exchange resin used in the ion exchange method comprises a chelating ion exchange resin;
or/and, in the step (c), the functional group of the chelating ion exchange resin comprises iminodiacetic acid or/and aminophosphonic acid groups.
5. The method for co-production of lithium, potassium, sodium and boron by using potassium extracted old brine according to claim 1, wherein in the step (d), the nanofiltration pressure is 1-12 MPa;
or/and, in the step (d), the purified brine is subjected to nanofiltration at least twice;
Or/and, in the step (d), the purified brine is subjected to nanofiltration for three times, nanofiltration produced water X and nanofiltration concentrated water Y are respectively obtained after the first nanofiltration, the nanofiltration produced water X is subjected to nanofiltration for a second time, the second nanofiltration produced water and the concentrated water S are respectively obtained, and the concentrated water S is refluxed into nanofiltration equipment; and carrying out third nanofiltration on the nanofiltration concentrated water Y to obtain nanofiltration concentrated water and produced water T respectively, and refluxing the produced water T into nanofiltration equipment.
6. The method for co-production of lithium, potassium, sodium and boron by using potassium extracted old brine according to claim 1, wherein in the step (e), the evaporating concentration temperature is 80-100 ℃;
or/and, in the step (e), the temperature of the freezing crystallization is 10-40 ℃;
or/and, in the step (e), the condensed water generated by evaporation concentration is recycled to the step (a) so as to dilute the potassium-extracted old brine.
7. The method for co-production of lithium, potassium, sodium and boron by using potassium-extracted old brine according to claim 1, wherein in the step (f), the ion exchange resin used in the ion exchange method comprises a chelate ion exchange resin;
or/and, in step (f), the functional group of the chelating ion exchange resin comprises an aminopolyhydroxy group.
8. The method for co-production of lithium, potassium, sodium and boron using potassium extracted old brine according to claim 1, wherein in step (g), the carbonate solution comprises sodium carbonate solution or/and potassium carbonate solution;
or/and, in the step (g), the molar ratio of the lithium element in the refined lithium-rich solution to the carbon element in the carbonate solution is 2:1.1 to 1.3;
or/and, in the step (g), the temperature of the mixed material is 80-100 ℃ in the reaction process.
9. The method for co-production of lithium, potassium, sodium and boron using potassium extracted old brine according to claim 1, wherein in step (h), the acid used for the acidification comprises hydrochloric acid;
or/and, in the step (h), the acidification is to control the pH value of the mixed material to be 1.7-1.95;
or/and, in the step (h), the temperature of the freezing crystallization is-10-5 ℃, and the time of the freezing crystallization is 3-5 h;
or/and, in the step (h), the boric acid is obtained after the solid-liquid separation, and meanwhile, the boron-removed brine is obtained, and the boron-removed brine is refluxed to the step (d) for carrying out the nanofiltration.
10. The use of the method for co-production of lithium potassium sodium boron by means of potassium extracting old brine according to any one of claims 1 to 9 in the preparation of battery grade lithium carbonate.
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