CN115947353A - Method for preparing lithium carbonate and iron phosphate by using lithium iron phosphate waste material and application thereof - Google Patents
Method for preparing lithium carbonate and iron phosphate by using lithium iron phosphate waste material and application thereof Download PDFInfo
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- CN115947353A CN115947353A CN202211603746.2A CN202211603746A CN115947353A CN 115947353 A CN115947353 A CN 115947353A CN 202211603746 A CN202211603746 A CN 202211603746A CN 115947353 A CN115947353 A CN 115947353A
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- lithium
- iron phosphate
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- carbonate
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- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 title claims abstract description 90
- 239000002699 waste material Substances 0.000 title claims abstract description 81
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 title claims abstract description 57
- 229910052808 lithium carbonate Inorganic materials 0.000 title claims abstract description 56
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 title claims abstract description 54
- 229910000398 iron phosphate Inorganic materials 0.000 title claims abstract description 51
- 238000000034 method Methods 0.000 title claims abstract description 45
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 55
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 54
- 239000003792 electrolyte Substances 0.000 claims abstract description 44
- 238000006243 chemical reaction Methods 0.000 claims abstract description 36
- 238000005868 electrolysis reaction Methods 0.000 claims abstract description 34
- 239000007788 liquid Substances 0.000 claims abstract description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 22
- 239000000460 chlorine Substances 0.000 claims abstract description 20
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims abstract description 13
- 238000001556 precipitation Methods 0.000 claims abstract description 13
- 239000000463 material Substances 0.000 claims abstract description 11
- 238000000926 separation method Methods 0.000 claims abstract description 11
- 238000002156 mixing Methods 0.000 claims abstract description 4
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical group [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 40
- 229910001416 lithium ion Inorganic materials 0.000 claims description 32
- 239000003014 ion exchange membrane Substances 0.000 claims description 26
- 239000001257 hydrogen Substances 0.000 claims description 17
- 229910052739 hydrogen Inorganic materials 0.000 claims description 17
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 16
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 10
- 229910052801 chlorine Inorganic materials 0.000 claims description 10
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 claims description 10
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 9
- 239000002245 particle Substances 0.000 claims description 9
- 230000008021 deposition Effects 0.000 claims description 7
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 6
- 239000011780 sodium chloride Substances 0.000 claims description 5
- 239000001569 carbon dioxide Substances 0.000 claims description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 238000002386 leaching Methods 0.000 abstract description 19
- 239000012535 impurity Substances 0.000 abstract description 10
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 abstract description 7
- 239000002253 acid Substances 0.000 abstract description 6
- 239000003513 alkali Substances 0.000 abstract description 6
- 238000011084 recovery Methods 0.000 abstract description 4
- 239000005955 Ferric phosphate Substances 0.000 abstract description 3
- 229940032958 ferric phosphate Drugs 0.000 abstract description 3
- 229910000399 iron(III) phosphate Inorganic materials 0.000 abstract description 3
- 239000000243 solution Substances 0.000 description 17
- 229910052751 metal Inorganic materials 0.000 description 12
- 239000002184 metal Substances 0.000 description 12
- 238000005406 washing Methods 0.000 description 11
- 238000001035 drying Methods 0.000 description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 7
- 238000001914 filtration Methods 0.000 description 7
- 239000000047 product Substances 0.000 description 7
- 238000001291 vacuum drying Methods 0.000 description 7
- 238000001514 detection method Methods 0.000 description 6
- 239000010439 graphite Substances 0.000 description 5
- 229910002804 graphite Inorganic materials 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 4
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- QWPPOHNGKGFGJK-UHFFFAOYSA-N hypochlorous acid Chemical compound ClO QWPPOHNGKGFGJK-UHFFFAOYSA-N 0.000 description 4
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 150000001768 cations Chemical class 0.000 description 3
- 239000012043 crude product Substances 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- BZSXEZOLBIJVQK-UHFFFAOYSA-N 2-methylsulfonylbenzoic acid Chemical compound CS(=O)(=O)C1=CC=CC=C1C(O)=O BZSXEZOLBIJVQK-UHFFFAOYSA-N 0.000 description 2
- 229910000929 Ru alloy Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 150000001450 anions Chemical class 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 238000010924 continuous production Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- -1 hydroxyl ions Chemical class 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 229910021645 metal ion Inorganic materials 0.000 description 2
- 150000007522 mineralic acids Chemical class 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- 238000009853 pyrometallurgy Methods 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 229910010707 LiFePO 4 Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229910002835 Pt–Ir Inorganic materials 0.000 description 1
- 229910002848 Pt–Ru Inorganic materials 0.000 description 1
- QSNQXZYQEIKDPU-UHFFFAOYSA-N [Li].[Fe] Chemical compound [Li].[Fe] QSNQXZYQEIKDPU-UHFFFAOYSA-N 0.000 description 1
- 238000007605 air drying Methods 0.000 description 1
- 239000008151 electrolyte solution Substances 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 230000003446 memory effect Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000012452 mother liquor Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 229910001414 potassium ion Inorganic materials 0.000 description 1
- 238000013404 process transfer Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
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- 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
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/84—Recycling of batteries or fuel cells
Landscapes
- Processing Of Solid Wastes (AREA)
- Electrolytic Production Of Metals (AREA)
Abstract
The invention relates to the technical field of waste lithium battery resource recovery, in particular to a method for preparing lithium carbonate and iron phosphate by using lithium iron phosphate waste and application thereof. The method comprises the following steps: the anode and the cathode are respectively arranged in Cl-containing electrolyte to form an anode region and a cathode region, and the electrolyte in the anode region also comprises lithium iron phosphate waste; electrifying the anode and the cathode for electrolysis, reacting the chlorine gas generated in the anode region with the water in the electrolyte and the lithium iron phosphate waste to generate the ferric phosphate and the Li + ；Li + Entering the cathode region from the anode region and enriching in the cathode region; after the electrolysis is finished, carrying out solid-liquid separation on the mixed material in the anode area to obtain iron phosphate; and mixing the lithium-containing liquid in the cathode region with carbonate, performing lithium precipitation reaction, and performing solid-liquid separation to obtain lithium carbonate. The invention realizes the leaching of lithium in the lithium iron phosphate waste material through electrolysis without consuming acid or alkali or removing impurities and simultaneously electrolyzes the lithiumAnd reacting the chlorine gas with the lithium iron phosphate waste to generate the iron phosphate.
Description
Technical Field
The invention relates to the technical field of waste lithium battery resource recovery, in particular to a method for preparing lithium carbonate and iron phosphate by using lithium iron phosphate waste and application thereof.
Background
The lithium iron phosphate battery has the advantages of long cycle life, good safety performance, no memory effect, environmental protection and the like, and is widely applied to the fields of electric automobiles and energy storage. With the rapid increase of the number of lithium iron phosphate batteries, the method means that a large number of lithium iron phosphate batteries are scrapped in the future, so that the method has important significance in recycling lithium in the lithium iron phosphate batteries.
At present, lithium iron phosphate can be recovered to obtain lithium through two modes of pyrometallurgy and wet leaching. The lithium content in the lithium iron phosphate is lower than 5%, and the pyrometallurgy has high energy consumption and low recovery rate. The wet leaching process transfers valuable metals in the lithium iron phosphate into a liquid phase for recycling through chemical, physical and other reactions, and although the method has the advantages of low energy consumption, high metal recycling rate, high purity of recycled products and the like, the method has large acid and alkali consumption, high impurities in the obtained lithium-rich mother liquor, large amount of generated slag and high impurities.
For example, CN104953200a is charged with lithium iron phosphateThe lithium in (1) is transferred to the negative electrode graphite to form Li x C, highly active Li x And C can react with water to prepare lithium hydroxide, and then lithium carbonate powder is obtained. However, lithium in the lithium iron phosphate cannot be fully recovered by the method, and the charging, full-electricity disassembly and water reaction of the recovered battery have great potential safety hazards.
For another example, in patents CN102903985a and CN104953200a, lithium iron phosphate positive electrode pieces to be recovered are subjected to heat treatment at high temperature, and finally, lithium carbonate is recovered by using acid, alkali, and the like. Although the method can effectively remove organic matters, carbon and other substances and oxidize ferrous iron, the heat treatment not only increases the energy consumption and the cost, but also the product generated after oxidation is not beneficial to leaching, thereby influencing the recovery rate.
For another example, CN107352524A prepared Li by wet leaching process 2 CO 3 And FePO 4 However, in the whole process, a large amount of inorganic acid and alkali are consumed, a large amount of new anions and cations are introduced, the difficulty of impurity removal is increased, and finally the obtained lithium carbonate product has high impurity content and unstable properties.
In view of the above, the present invention is particularly proposed.
Disclosure of Invention
The invention aims to provide a method for preparing lithium carbonate and iron phosphate by using lithium iron phosphate waste, which is characterized in that the lithium in the lithium iron phosphate waste is leached through electrolysis without consuming acid or alkali or removing impurities, and chlorine generated by electrolysis reacts with the lithium iron phosphate waste to generate the iron phosphate.
The second purpose of the present invention is to provide the application of lithium carbonate and iron phosphate prepared by the method for preparing lithium carbonate and iron phosphate by using lithium iron phosphate waste material in a lithium ion battery.
In order to achieve the above purpose of the present invention, the following technical solutions are adopted:
the invention provides a method for preparing lithium carbonate and iron phosphate by utilizing lithium iron phosphate waste, which comprises the following steps:
placing the anode and the cathode in an electrolyte respectively, wherein the electrolyte comprises Cl - A lithium ion exchange membrane disposed between the anode and the cathode, the lithium ion exchange membrane separating the anode and the cathode to form an anode region and a cathode region; the electrolyte in the anode region also comprises a lithium iron phosphate waste material; the anode region is arranged in a closed manner;
electrifying the anode and the cathode for electrolysis, and reacting the chlorine generated in the anode region with water in the electrolyte and the lithium iron phosphate waste to generate iron phosphate and Li + ；
Under the action of electric potential and the lithium ion exchange membrane, the Li + Entering the cathode region from the anode region, and enriching in the cathode region;
after the electrolysis is finished, carrying out solid-liquid separation on the mixed material in the anode area to obtain the iron phosphate; and mixing the lithium-containing liquid in the cathode region with carbonate or introducing carbon dioxide into the lithium-containing liquid in the cathode region to carry out lithium deposition reaction, and carrying out solid-liquid separation after the lithium deposition reaction is finished to obtain the lithium carbonate.
Preferably, a filter screen is further arranged between the anode and the cathode, and the filter screen is arranged in the anode region and attached to the lithium ion exchange membrane;
preferably, the aperture of the filter screen is smaller than the particle size of the lithium iron phosphate waste material.
Preferably, the electrolyte comprises at least one of a LiCl solution, a NaCl solution, and a KCl solution;
preferably, the molar concentration of the electrolyte is 0.01-1 mol/L.
Preferably, the mass ratio of the electrolyte to the lithium iron phosphate waste material is 2-5: 1.
preferably, the voltage of the electrolysis is 0.1-5V;
preferably, the time of the electrolysis is 0.5 to 10 hours.
Preferably, the top end of the cathode region is provided with a hydrogen collecting device for collecting the hydrogen generated by the cathode region.
Preferably, the carbonate comprises Na 2 CO 3 And/or NaHCO 3 ；
Preferably, the molar ratio of lithium element in the lithium-containing solution to carbonate in carbonate is 1.8-2: 1.
preferably, the temperature of the lithium deposition reaction is 35-95 ℃, and the time of the lithium deposition reaction is 10-60 min.
Preferably, the purity of the lithium carbonate is more than or equal to 99%.
The invention also provides application of the lithium carbonate and the iron phosphate prepared by the method for preparing the lithium carbonate and the iron phosphate by utilizing the lithium iron phosphate waste material in the lithium ion battery.
Compared with the prior art, the invention has the beneficial effects that:
(1) The method for preparing lithium carbonate and iron phosphate by using the lithium iron phosphate waste material provided by the invention comprises the step of electrolyzing Cl-containing - And the mixed solution of the lithium iron phosphate waste realizes the leaching of lithium in the lithium iron phosphate waste. In the whole process, oxidants such as hydrogen peroxide or sodium chlorate and the like are not used, acid or alkali is not consumed, and the cost is obviously reduced.
(2) According to the method for preparing lithium carbonate and iron phosphate by using the lithium iron phosphate waste, impurity removal treatment is not needed, and impurity ions in the product can be removed only by washing.
(3) The method for preparing lithium carbonate and iron phosphate by using the lithium iron phosphate waste material has the advantages of high purity of the prepared lithium carbonate, simplicity, low cost, environmental protection, continuous production and the like.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic diagram illustrating the principle of the method for preparing lithium carbonate and iron phosphate by using lithium iron phosphate waste material according to the present invention.
Detailed Description
The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and the detailed description, but those skilled in the art will understand that the following described embodiments are a part of the embodiments of the present invention, rather than all of the embodiments, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are conventional products which are not indicated by manufacturers and are commercially available.
In a first aspect, the invention provides a method for preparing lithium carbonate and iron phosphate by using lithium iron phosphate waste, which comprises the following steps:
the anode and cathode are placed separately in an intervening) electrolyte comprising Cl - A lithium ion exchange membrane disposed between the anode and the cathode, the lithium ion exchange membrane separating the anode and the cathode to form an anode region and a cathode region; the electrolyte in the anode region also comprises a lithium iron phosphate waste material (called LEP waste material for short); the anode area is arranged in a closed mode.
The lithium ion exchange membrane can only pass through lithium metal ions, but cannot pass through other metal ions and anions, and cannot pass through gas. I.e. only Li is allowed between the anode region and the cathode region + And (4) passing. The lithium ion exchange membrane is used for making Li + Enter the cathode region from the anode region and isolate other metal ions from entering the cathode region.
The lithium ion exchange membrane separates the anode and the cathode to form an anode region and a cathode region, namely, the lithium ion exchange membrane is used as a boundary, one side close to the anode is the anode region, and one side close to the cathode is the cathode region.
The anode region is arranged in a closed manner, namely, the gas in the anode region cannot escape into the air, and the external gas cannot enter into the anode region, so that the chlorine generated after electrolysis can be prevented from escaping, and the chlorine is ensured to be sufficient, so that the reaction is fully carried out. However, li is allowed between the anode region and the cathode region + And (4) passing.
The cathode region is electrolytically generated hydrogen, so that the cathode region can be arranged in a closed manner or in an open manner, preferably in a closed manner, and a container or a device which can collect hydrogen is provided for recovering hydrogen.
Electrifying the anode and the cathode for electrolysis, reacting the chlorine generated in the anode region with water in electrolyte and the lithium iron phosphate waste (acid leaching) to generate iron phosphate and Li + 。
Wherein the reaction occurring at the anode region comprises at least one of:
2Cl - -2e - →Cl 2 。
Cl 2 +H 2 O→2H + +Cl - +ClO - 。
2LiFePO 4 +2H + +ClO - →2FePO 4 +2Li + +Cl - +H 2 O。
that is, under the action of electrolysis, cl-in the electrolyte in the anode region loses electrons to generate chlorine, and the chlorine dissolves in water and reacts to generate HCl, HClO and HClO 3 Simultaneously, the lithium iron phosphate waste is mixed with HCl, HClO and HClO 3 The reaction produces iron phosphate and leaches lithium.
Under the action of electric potential and the lithium ion exchange membrane, the Li + You YangThe polar region enters the cathode region and is enriched in the cathode region, so that the purpose of concentration is achieved.
The reaction taking place in the cathode region comprises: 2H 2 O+2e - →H 2 ↑+2OH-。
After the electrolysis is finished, the main components of the mixed material in the anode region comprise iron phosphate, and the main components of the lithium-containing liquid in the cathode region comprise lithium ions and hydroxyl ions.
After the electrolysis is finished, carrying out solid-liquid separation on the mixed material in the anode region (after reaction) to obtain the iron phosphate; and mixing the lithium-containing liquid in the cathode region with carbonate, or introducing carbon dioxide gas into the lithium-containing liquid in the cathode region to carry out lithium precipitation reaction, and carrying out solid-liquid separation after the lithium precipitation reaction is finished to obtain the lithium carbonate.
The method realizes the leaching of lithium in the lithium iron phosphate waste material by electrolyzing the mixed solution containing Cl < - > and the lithium iron phosphate waste material. In the whole process, oxidants such as hydrogen peroxide or sodium chlorate and the like are not used, and inorganic acids or alkalis such as hydrochloric acid, concentrated sulfuric acid, nitric acid and the like are not consumed. In addition, impurity removal treatment is not needed, and impurity ions in the product can be removed only by washing with water.
The method for preparing lithium carbonate and iron phosphate by using the lithium iron phosphate waste material has the advantages of high purity of the prepared lithium carbonate, simplicity, low cost, environmental protection, continuous production and the like.
In some specific embodiments of the present invention, the waste lithium iron phosphate includes at least one of an unqualified material generated in a production process of lithium iron phosphate, a waste lithium iron phosphate cathode generated in a production process of a lithium battery, and a waste lithium iron phosphate cathode after disassembly of a scrapped lithium battery.
In some embodiments of the present invention, the metal cations in the electrolyte include active metal cations, such as potassium ions, sodium ions, lithium ions, and the like, but are not limited thereto.
By taking an electrolyte as a NaCl solution as an example, a schematic diagram of the method for preparing lithium carbonate and iron phosphate by using a lithium iron phosphate waste material provided by the present invention is shown in fig. 1.
Preferably, a filter screen is further arranged between the anode and the cathode, and the filter screen is arranged in the anode area and attached to the lithium ion exchange membrane.
Preferably, the aperture of the filter screen is smaller than the particle size of the lithium iron phosphate waste.
The filter screen is used for filtering the lithium iron phosphate waste and the generated iron phosphate so as to prevent the waste from entering the lithium ion exchange membrane to damage the lithium ion exchange membrane.
In some specific embodiments of the invention, the pore size of the filter screen is 0.2 to 1 μm, including but not limited to values of any one or a range between any two of 0.3 μm, 0.5 μm, 0.7 μm, 0.9 μm; the particle size of the lithium iron phosphate waste material is larger than 1 mu m.
Preferably, the electrolyte includes at least one of a LiCl solution, a NaCl solution, and a KCl solution.
The solvent used in the electrolyte is water.
Preferably, the electrolyte has a molar concentration of 0.01 to 1mol/L, including but not limited to any one of 0.05mol/L, 0.1mol/L, 0.3mol/L, 0.5mol/L, 0.7mol/L, 0.9mol/L or a range between any two.
In which the concentration of the electrolyte, that is, the concentration of chloride ions, is too high, resulting in the inhibition of the generation of Cl 2 And reacting with water, thereby influencing the leaching of lithium in the lithium iron phosphate.
Preferably, the mass ratio of the electrolyte to the lithium iron phosphate waste material is 2-5: 1, including but not limited to, any one of 2:1, 3:1, 4:1, 5:1, or a range of values between any two.
The use of the above mass ratio and the above molar concentration is advantageous for the reaction to proceed smoothly.
Preferably, the voltage of the electrolysis is 0.1-5V; including but not limited to, a point value of any one of 0.5V, 1V, 2V, 3V, 4V, or a range of values between any two.
Preferably, the time of electrolysis is 0.5 to 10 hours, including but not limited to any one of 1 hour, 3 hours, 5 hours, 7 hours, 9 hours or a range between any two.
In some embodiments of the invention, the anode comprises at least one of a metal Pt, a metal Ir, a metal Ru, a Pt-Ir alloy, an Ir-Ru alloy, a Pt-Ru alloy, and a Pt-Ir-Ru alloy.
In some specific embodiments of the invention, the cathode comprises at least one of metal Pt, metal Ni, metal Cu, metal Ru, metal Ti, and a carbon electrode (e.g., a graphite electrode).
Preferably, the top end of the cathode region is provided with a hydrogen collecting device for collecting the hydrogen generated by the cathode region. See figure 1 in particular.
The collected hydrogen can be used as fuel, and the added value is improved.
Preferably, the carbonate comprises Na 2 CO 3 And/or NaHCO 3 。
Preferably, the molar ratio of the lithium element in the lithium-containing solution to the carbonate in the carbonate is 1.8-2: 1, including but not limited to 1.8.
Preferably, the temperature of the lithium precipitation reaction is 35 to 95 ℃, including but not limited to any one of 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃ or a range between any two; the time of the lithium precipitation reaction is 10-60 min, including but not limited to the point value of any one of 20min, 30min, 40min and 50min or the range value between any two.
In some specific embodiments of the present invention, after the solid-liquid separation is completed after the lithium deposition reaction, the method further comprises the steps of sequentially performing washing and drying. Preferably, the washing is carried out by using water, the temperature of the water is 40-95 ℃, and the washing times are 1-3.
In some specific embodiments of the present invention, after the solid-liquid separation of the mixed material in the anode region, the method further comprises the step of washing and drying the solid material obtained after the solid-liquid separation. Preferably, the washing is performed with water. More preferably, the drying comprises: drying for 4-12 h at 60-150 ℃ in a vacuum drying oven or a forced air drying oven.
Preferably, the lithium carbonate has a purity of 99% or more, including but not limited to any one of 99.1%, 99.3%, 99.5%, 99.7%, 99.8%, 99.9%, 99.93%, 99.94%, or a range between any two.
In a second aspect, the invention provides an application of lithium carbonate and iron phosphate prepared by the method for preparing lithium carbonate and iron phosphate by using lithium iron phosphate waste material in a lithium ion battery.
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 illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are conventional products which are commercially available, and are not indicated by manufacturers.
Example 1
The method for preparing lithium carbonate and iron phosphate by using lithium iron phosphate waste material provided by the embodiment comprises the following steps:
(1) Pt is used as an anode, graphite is used as a cathode, a NaCl aqueous solution with the molar concentration of 0.1mol/L is used as an electrolyte, the anode and the cathode are respectively inserted into the electrolyte, and the mass ratio of the electrolyte to the lithium iron phosphate waste is 3.5:1, and a lithium ion exchange membrane is arranged between the cathode and the anode, and the anode and the cathode are separated to form an anode region and a cathode region. The anode region is closed to prevent chlorine gas from escaping. And arranging a filter screen in the anode region, enabling the filter screen to be attached to the lithium ion exchange membrane, and then adding the lithium iron phosphate waste into the electrolyte in the anode region, wherein the aperture of the filter screen is smaller than the particle size of the lithium iron phosphate waste.
(2) Electrifying the anode and the cathode, applying a voltage of 0.25V for electrolysis, and reacting the chlorine gas generated in the anode region with the water in the electrolyte and the lithium iron phosphate waste to generate the iron phosphate and the Li + . Under the action of potential and lithium ion exchange membrane, li + Enters the cathode region from the anode region and is enriched in the cathode region. The top end of the cathode region is provided with a hydrogen collecting device for collecting hydrogen generated by the cathode during electrolysis. Wherein the electrolysis time is 4h.
(3) And after the electrolysis is finished, filtering the reacted mixed material in the anode area, washing filter residues twice by using pure water, and drying the filter residues in a vacuum drying oven at 90 ℃ for 4 hours to obtain a crude product of iron phosphate.
(4) And (2) adding anhydrous sodium carbonate into the lithium-containing liquid after reaction in the cathode region to perform lithium precipitation reaction, wherein the molar ratio of the lithium element in the lithium-containing liquid to the anhydrous sodium carbonate is 1.9:1, the reaction temperature is 95 ℃, the reaction time is 40min, after the lithium precipitation reaction is finished, filtering is carried out, then filter residue is washed twice by pure water at 70 ℃, and then the filter residue is placed in a vacuum drying oven to be dried for 4h at 90 ℃ to obtain lithium carbonate.
Through detection, li in the waste lithium iron phosphate in the embodiment + The leaching rate (the calculation formula is: the mass of lithium element in the lithium-containing solution obtained after the reaction in the cathode region after the electrolysis/the mass of lithium element in the lithium iron phosphate waste material before the electrolysis × 100%, and the same applies to the following examples) was 95.37%, and the purity of lithium carbonate produced in this example was 99.39%.
Example 2
The method for preparing lithium carbonate and iron phosphate by using lithium iron phosphate waste material provided by the embodiment comprises the following steps:
(1) Taking Pt as an anode, graphite as a cathode, taking a LiCl aqueous solution with the molar concentration of 0.1mol/L as an electrolyte, respectively inserting the anode and the cathode into the electrolyte, wherein the mass ratio of the electrolyte to the lithium iron phosphate waste material is 3.5. The anode region is closed to prevent chlorine gas from escaping. And arranging a filter screen in the anode region, enabling the filter screen to be attached to the lithium ion exchange membrane, and then adding the lithium iron phosphate waste into the electrolyte in the anode region, wherein the aperture of the filter screen is smaller than the particle size of the lithium iron phosphate waste.
(2) Electrifying the anode and cathode, applying 4V voltage for electrolysis, and generating chlorine gas in the anode regionThen reacts with water in electrolyte and lithium iron phosphate waste to generate ferric phosphate and Li + . Under the action of electric potential and the lithium ion exchange membrane, the Li + Enters the cathode region from the anode region and is enriched in the cathode region. The top end of the cathode region is provided with a hydrogen collecting device for collecting hydrogen generated by the cathode during electrolysis. Wherein the electrolysis time is 1h.
(3) And after the electrolysis is finished, filtering the reacted mixed material in the anode area, washing filter residues twice by using pure water, and drying the filter residues in a vacuum drying oven at 90 ℃ for 4 hours to obtain a crude product of iron phosphate.
(4) And (2) adding anhydrous sodium carbonate into the lithium-containing liquid after reaction in the cathode region to perform lithium precipitation reaction, wherein the molar ratio of the lithium element in the lithium-containing liquid to the anhydrous sodium carbonate is 1.9:1, reacting at 50 ℃ for 60min, filtering after the lithium precipitation reaction is finished, washing filter residues twice with pure water at 70 ℃, and drying in a vacuum drying oven at 90 ℃ for 4h to obtain lithium carbonate.
Through detection, li in the waste lithium iron phosphate in the embodiment + The leaching rate of (2) was 95.44%, and the purity of the lithium carbonate prepared in this example was 99.43%.
Example 3
The method for preparing lithium carbonate and iron phosphate by using lithium iron phosphate waste material provided by the embodiment comprises the following steps:
(1) Taking Pt as an anode, graphite as a cathode, taking a KCl aqueous solution with the molar concentration of 0.1mol/L as electrolyte, and respectively inserting the anode and the cathode into the electrolyte, wherein the mass ratio of the electrolyte to the lithium iron phosphate waste is 3.5:1, and a lithium ion exchange membrane is arranged between the cathode and the anode, and the anode and the cathode are separated to form an anode region and a cathode region. The anode region is closed to prevent chlorine gas from escaping. And arranging a filter screen in the anode region, enabling the filter screen to be attached to the lithium ion exchange membrane, and then adding the lithium iron phosphate waste into the electrolyte in the anode region, wherein the aperture of the filter screen is smaller than the particle size of the lithium iron phosphate waste.
(2) Electrifying the anode and the cathode, applying 2V voltage for electrolysis, generating chlorine in the anode region, and reacting with the electrolyteThe water and the lithium iron phosphate waste react to generate ferric phosphate and Li + . Under the action of electric potential and the lithium ion exchange membrane, the Li + Enters the cathode region from the anode region and is enriched in the cathode region. The top end of the cathode region is provided with a hydrogen collecting device for collecting hydrogen generated by the cathode during electrolysis. Wherein the electrolysis time is 8h.
(3) And after the electrolysis is finished, filtering the reacted mixed material in the anode area, washing filter residues twice by using pure water, and drying the filter residues in a vacuum drying oven at 90 ℃ for 4 hours to obtain a crude product of iron phosphate.
(4) Adding NaHCO into lithium-containing liquid after reaction in a cathode region 3 Performing a lithium precipitation reaction, wherein lithium element in the lithium-containing liquid and NaHCO 3 In a molar ratio of 1.9:1, the reaction temperature is 70 ℃, the reaction time is 20min, after the lithium precipitation reaction is finished, filtering is carried out, then filter residue is washed twice by pure water at 70 ℃, and then the filter residue is placed in a vacuum drying oven to be dried for 4h at 90 ℃ to obtain the lithium carbonate.
Through detection, li in the waste lithium iron phosphate in the embodiment + The leaching rate of (d) was 95.53%, and the purity of lithium carbonate obtained in this example was 99.41%.
Example 4
The method for preparing lithium carbonate and iron phosphate from lithium iron phosphate scrap provided in this example is substantially the same as that of example 2, except that in step (1), the molar concentration of the aqueous LiCl solution is replaced with 3mol/L.
Through detection, li in the waste lithium iron phosphate in the embodiment + The leaching rate of (d) was 75.36%, and the purity of lithium carbonate prepared in this example was 99.39%.
Example 5
The method for preparing lithium carbonate and iron phosphate by using the lithium iron phosphate waste material provided in this example is substantially the same as that in example 2, except that in step (1), the mass ratio of the electrolyte to the lithium iron phosphate waste material is replaced by 2:1.
through detection, li in the waste lithium iron phosphate in the embodiment + The leaching rate of (1) was 84.79%, and the purity of the lithium carbonate prepared in this example was 99.38%.
As can be seen by comparing the purity detection results of the lithium carbonate in the embodiments, the lithium carbonate prepared by the method provided by the present invention has a higher purity.
By comparing Li of example 1 and example 4 + As a result of the leaching rate, the concentration of the electrolyte solution was determined for Li + The leaching rate of (A) has a more significant influence.
By comparing Li of example 1 and example 5 + The leaching rate results show that the mass ratio (solid-to-liquid ratio) of the electrolyte to the lithium iron phosphate scrap also affects Li + The leaching rate of (A). This is because, in the solid-liquid heterogeneous reaction, when the solid-liquid ratio is large (i.e., example 5), the newly formed solid phase is inevitably wrapped in the original LiFePO 4 The surface of the solid particles prevents the solid particles from fully contacting with the liquid phase, thus inhibiting the reaction and reducing Li + The leaching rate of (A).
While particular embodiments of the present invention have been illustrated and described, it will be appreciated that the above embodiments are merely illustrative of the technical solution of the present invention and are not restrictive; those of ordinary skill in the art will understand that: modifications may be made to the above-described embodiments, or equivalents may be substituted for some or all of the features thereof without departing from the spirit and scope of the present invention; the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention; it is therefore intended to cover in the appended claims all such alternatives and modifications that are within the scope of the invention.
Claims (10)
1. The method for preparing lithium carbonate and iron phosphate by using the lithium iron phosphate waste material is characterized by comprising the following steps:
respectively placing an anode and a cathode in electrolyte, wherein the electrolyte comprises Cl < - >, a lithium ion exchange membrane is arranged between the anode and the cathode, and the lithium ion exchange membrane separates the anode and the cathode to form an anode region and a cathode region; the electrolyte in the anode region also comprises a waste lithium iron phosphate material; the anode area is arranged in a closed mode;
electrifying the anode and the cathode for electrolysis, and reacting the chlorine generated in the anode region with water in the electrolyte and the lithium iron phosphate waste to generate iron phosphate and Li + ；
Under the action of electric potential and the lithium ion exchange membrane, the Li + Entering the cathode region from the anode region, and enriching in the cathode region;
after the electrolysis is finished, carrying out solid-liquid separation on the mixed material in the anode area to obtain the iron phosphate; and mixing the lithium-containing liquid in the cathode region with carbonate or introducing carbon dioxide into the lithium-containing liquid in the cathode region to carry out lithium deposition reaction, and carrying out solid-liquid separation after the lithium deposition reaction is finished to obtain the lithium carbonate.
2. The method for preparing lithium carbonate and iron phosphate by using lithium iron phosphate waste material according to claim 1, wherein a filter screen is further arranged between the anode and the cathode, and the filter screen is arranged in the anode region and attached to the lithium ion exchange membrane;
preferably, the aperture of the filter screen is smaller than the particle size of the lithium iron phosphate waste.
3. The method for preparing lithium carbonate and iron phosphate using lithium iron phosphate waste material according to claim 1, wherein the electrolyte comprises at least one of a LiCl solution, a NaCl solution, and a KCl solution;
preferably, the molar concentration of the electrolyte is 0.01-1 mol/L.
4. The method for preparing lithium carbonate and iron phosphate by using the lithium iron phosphate waste material as claimed in claim 1, wherein the mass ratio of the electrolyte to the lithium iron phosphate waste material is 2-5: 1.
5. the method for preparing lithium carbonate and iron phosphate by using lithium iron phosphate waste material according to claim 1, wherein the voltage of the electrolysis is 0.1-5V;
preferably, the time of the electrolysis is 0.5 to 10 hours.
6. The method for preparing lithium carbonate and iron phosphate by using the lithium iron phosphate waste material as claimed in claim 1, wherein a hydrogen collecting device is arranged at the top end of the cathode region, and the hydrogen collecting device is used for collecting hydrogen generated in the cathode region.
7. The method for preparing lithium carbonate and iron phosphate by using lithium iron phosphate waste material according to claim 1, wherein the carbonate comprises Na 2 CO 3 And/or NaHCO 3 ；
Preferably, the molar ratio of the lithium element in the lithium-containing solution to the carbonate in the carbonate is 1.8-2: 1.
8. the method for preparing lithium carbonate and iron phosphate by using the lithium iron phosphate waste material as claimed in claim 1, wherein the temperature of the lithium precipitation reaction is 35-95 ℃, and the time of the lithium precipitation reaction is 10-60 min.
9. The method for preparing lithium carbonate and iron phosphate from lithium iron phosphate waste according to any one of claims 1 to 8, wherein the purity of the lithium carbonate is not less than 99%.
10. The use of lithium carbonate and iron phosphate produced by the method for producing lithium carbonate and iron phosphate using lithium iron phosphate waste material according to any one of claims 1 to 9 in a lithium ion battery.
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| CN111484043A (en) * | 2020-03-05 | 2020-08-04 | 赣州龙凯科技有限公司 | Comprehensive recovery method of waste lithium manganate and lithium iron phosphate cathode material |
| CN111653846A (en) * | 2020-07-27 | 2020-09-11 | 中南大学 | Treatment method of waste lithium iron phosphate battery |
| CN112981433A (en) * | 2021-02-04 | 2021-06-18 | 中南大学 | Method for recycling waste lithium iron phosphate anode material by electrolyzing cation membrane pulp and recycled lithium hydroxide |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2017215282A1 (en) * | 2016-06-17 | 2017-12-21 | 天齐锂业股份有限公司 | Method for recycling lithium in anode material of lithium battery by means of electrochemical process |
| CN111484043A (en) * | 2020-03-05 | 2020-08-04 | 赣州龙凯科技有限公司 | Comprehensive recovery method of waste lithium manganate and lithium iron phosphate cathode material |
| CN111653846A (en) * | 2020-07-27 | 2020-09-11 | 中南大学 | Treatment method of waste lithium iron phosphate battery |
| CN112981433A (en) * | 2021-02-04 | 2021-06-18 | 中南大学 | Method for recycling waste lithium iron phosphate anode material by electrolyzing cation membrane pulp and recycled lithium hydroxide |
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