CN115611251A - Method for regenerating iron phosphate by extracting lithium slag from waste lithium iron phosphate cathode material - Google Patents
Method for regenerating iron phosphate by extracting lithium slag from waste lithium iron phosphate cathode material Download PDFInfo
- Publication number
- CN115611251A CN115611251A CN202110806701.4A CN202110806701A CN115611251A CN 115611251 A CN115611251 A CN 115611251A CN 202110806701 A CN202110806701 A CN 202110806701A CN 115611251 A CN115611251 A CN 115611251A
- Authority
- CN
- China
- Prior art keywords
- iron phosphate
- temperature
- liquid phase
- phosphate
- precipitation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 title claims abstract description 199
- 229910000398 iron phosphate Inorganic materials 0.000 title claims abstract description 156
- 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 78
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 65
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 65
- 238000000034 method Methods 0.000 title claims abstract description 65
- 239000002699 waste material Substances 0.000 title claims abstract description 64
- 239000002893 slag Substances 0.000 title claims abstract description 56
- 230000001172 regenerating effect Effects 0.000 title claims abstract description 26
- 239000010406 cathode material Substances 0.000 title claims description 34
- 238000001556 precipitation Methods 0.000 claims abstract description 59
- 239000007788 liquid Substances 0.000 claims abstract description 50
- 239000007774 positive electrode material Substances 0.000 claims abstract description 8
- 239000007791 liquid phase Substances 0.000 claims description 103
- 239000002253 acid Substances 0.000 claims description 52
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 49
- 238000001354 calcination Methods 0.000 claims description 45
- 238000000605 extraction Methods 0.000 claims description 45
- 239000005955 Ferric phosphate Substances 0.000 claims description 44
- 229940032958 ferric phosphate Drugs 0.000 claims description 44
- 229910000399 iron(III) phosphate Inorganic materials 0.000 claims description 44
- 238000010438 heat treatment Methods 0.000 claims description 43
- 239000002245 particle Substances 0.000 claims description 39
- 238000006243 chemical reaction Methods 0.000 claims description 33
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 32
- 238000004090 dissolution Methods 0.000 claims description 32
- 238000003756 stirring Methods 0.000 claims description 26
- 239000010405 anode material Substances 0.000 claims description 21
- 238000000926 separation method Methods 0.000 claims description 21
- 238000002156 mixing Methods 0.000 claims description 18
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 16
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 16
- 239000003570 air Substances 0.000 claims description 16
- 239000012298 atmosphere Substances 0.000 claims description 15
- 238000007254 oxidation reaction Methods 0.000 claims description 14
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 12
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 12
- 239000001301 oxygen Substances 0.000 claims description 12
- 229910052760 oxygen Inorganic materials 0.000 claims description 12
- 239000007800 oxidant agent Substances 0.000 claims description 11
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 claims description 10
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 8
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 8
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 8
- USHAGKDGDHPEEY-UHFFFAOYSA-L potassium persulfate Chemical compound [K+].[K+].[O-]S(=O)(=O)OOS([O-])(=O)=O USHAGKDGDHPEEY-UHFFFAOYSA-L 0.000 claims description 6
- 238000004321 preservation Methods 0.000 claims description 6
- 229910001870 ammonium persulfate Inorganic materials 0.000 claims description 5
- 230000001590 oxidative effect Effects 0.000 claims description 5
- 229910052786 argon Inorganic materials 0.000 claims description 4
- 229910052757 nitrogen Inorganic materials 0.000 claims description 4
- 239000005708 Sodium hypochlorite Substances 0.000 claims description 3
- 238000011534 incubation Methods 0.000 claims description 3
- JRKICGRDRMAZLK-UHFFFAOYSA-N peroxydisulfuric acid Chemical compound OS(=O)(=O)OOS(O)(=O)=O JRKICGRDRMAZLK-UHFFFAOYSA-N 0.000 claims description 3
- FHHJDRFHHWUPDG-UHFFFAOYSA-N peroxysulfuric acid Chemical compound OOS(O)(=O)=O FHHJDRFHHWUPDG-UHFFFAOYSA-N 0.000 claims description 3
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 claims description 3
- LCPVQAHEFVXVKT-UHFFFAOYSA-N 2-(2,4-difluorophenoxy)pyridin-3-amine Chemical compound NC1=CC=CN=C1OC1=CC=C(F)C=C1F LCPVQAHEFVXVKT-UHFFFAOYSA-N 0.000 claims description 2
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims description 2
- 229910052734 helium Inorganic materials 0.000 claims description 2
- 239000001307 helium Substances 0.000 claims description 2
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 2
- BMTOKWDUYJKSCN-UHFFFAOYSA-K iron(3+);phosphate;dihydrate Chemical compound O.O.[Fe+3].[O-]P([O-])([O-])=O BMTOKWDUYJKSCN-UHFFFAOYSA-K 0.000 claims description 2
- BAZAXWOYCMUHIX-UHFFFAOYSA-M sodium perchlorate Chemical compound [Na+].[O-]Cl(=O)(=O)=O BAZAXWOYCMUHIX-UHFFFAOYSA-M 0.000 claims description 2
- 229910001488 sodium perchlorate Inorganic materials 0.000 claims description 2
- CHQMHPLRPQMAMX-UHFFFAOYSA-L sodium persulfate Substances [Na+].[Na+].[O-]S(=O)(=O)OOS([O-])(=O)=O CHQMHPLRPQMAMX-UHFFFAOYSA-L 0.000 claims description 2
- 125000004122 cyclic group Chemical group 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 63
- 239000000047 product Substances 0.000 description 47
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 26
- 229910052698 phosphorus Inorganic materials 0.000 description 26
- 239000011574 phosphorus Substances 0.000 description 26
- 230000000052 comparative effect Effects 0.000 description 22
- 238000001914 filtration Methods 0.000 description 22
- 238000011084 recovery Methods 0.000 description 21
- 229910052742 iron Inorganic materials 0.000 description 10
- 238000005406 washing Methods 0.000 description 9
- 238000000498 ball milling Methods 0.000 description 8
- 239000013078 crystal Substances 0.000 description 7
- 239000012535 impurity Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 238000004064 recycling Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 238000005303 weighing Methods 0.000 description 6
- 239000008367 deionised water Substances 0.000 description 5
- 229910021641 deionized water Inorganic materials 0.000 description 5
- 238000005245 sintering Methods 0.000 description 5
- 239000011230 binding agent Substances 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 239000003638 chemical reducing agent Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000011261 inert gas Substances 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- 230000009466 transformation Effects 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 2
- 239000003463 adsorbent Substances 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 238000009616 inductively coupled plasma Methods 0.000 description 2
- LEAMSPPOALICQN-UHFFFAOYSA-H iron(2+);diphosphate;octahydrate Chemical compound O.O.O.O.O.O.O.O.[Fe+2].[Fe+2].[Fe+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O LEAMSPPOALICQN-UHFFFAOYSA-H 0.000 description 2
- 238000002386 leaching Methods 0.000 description 2
- 238000003801 milling Methods 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- DPTATFGPDCLUTF-UHFFFAOYSA-N phosphanylidyneiron Chemical compound [Fe]#P DPTATFGPDCLUTF-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 2
- 239000010452 phosphate Substances 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- 239000002243 precursor Substances 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- -1 separators Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 1
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 1
- 235000011130 ammonium sulphate Nutrition 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 229940116007 ferrous phosphate Drugs 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910000155 iron(II) phosphate Inorganic materials 0.000 description 1
- SDEKDNPYZOERBP-UHFFFAOYSA-H iron(ii) phosphate Chemical compound [Fe+2].[Fe+2].[Fe+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O SDEKDNPYZOERBP-UHFFFAOYSA-H 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910000403 monosodium phosphate Inorganic materials 0.000 description 1
- 235000019799 monosodium phosphate Nutrition 0.000 description 1
- 239000003960 organic solvent Substances 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
- 238000002360 preparation method Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000004537 pulping Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- AJPJDKMHJJGVTQ-UHFFFAOYSA-M sodium dihydrogen phosphate Chemical compound [Na+].OP(O)([O-])=O AJPJDKMHJJGVTQ-UHFFFAOYSA-M 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/26—Phosphates
- C01B25/37—Phosphates of heavy metals
- C01B25/375—Phosphates of heavy metals of iron
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
-
- 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
Abstract
The invention discloses a method for regenerating iron phosphate by extracting lithium slag from a waste lithium iron phosphate positive electrode material. The method has the advantages of low treatment cost, simple flow, cyclic utilization of the precipitation liquid in the treatment process, less waste generated after treatment, small influence on the environment and good industrial application prospect.
Description
Technical Field
The invention relates to the technical field of lithium battery recovery, in particular to a method for regenerating iron phosphate by extracting lithium slag from a waste lithium iron phosphate positive electrode material.
Background
The lithium iron phosphate battery is a main flow power battery in the initial development stage of the new energy automobile industry and has the outstanding advantages of good safety performance, long cycle life, low cost and the like. Influenced by factors such as industrial technology upgrading and battery aging, a large number of scrapped lithium iron phosphate batteries exist in the current market. Since lithium iron phosphate batteries contain valuable but harmful substances such as positive electrodes, negative electrodes, electrolytes, separators, binders (PVDF), and the like, it is currently the focus of research to adopt appropriate recycling techniques to utilize the valuable components therein.
The iron phosphate is a core precursor for preparing the lithium iron phosphate anode material, and the preparation process mainly comprises a one-step method and a two-step method. The lithium iron phosphate battery positive electrode material is prepared from iron source and phosphorus source with higher purity by a two-step method, and the quality of the iron phosphate can be improved by the two-step method compared with the one-step method. The two-step process includes two synthesis modes: the first synthesis mode is to first use a ferrous iron source (such as FeSO) 4 ·7H 2 O) and a phosphorus source (e.g., (NH) 4 ) 2 HPO 4 ) Adjusting the pH value to 4-5 by ammonia water, and precipitating to obtain ferrous phosphate octahydrate (Fe) 3 (PO 4 ) 2 ·8H 2 O), washing ferrous phosphate octahydrate, stirring and pulping by using aqueous solution, adding phosphoric acid and hydrogen peroxide into the pulp, heating the pulp to below 100 ℃ to obtain ferric phosphate dihydrate crystal (FePO) 4 ·2H 2 O), the ferric phosphate dihydrate crystal is washed again to improve the purity; the second synthesis mode is to make the ferrous iron source (such as FeSO) 4 ·7H 2 O) and a phosphorus source (e.g., (NH) 4 ) 2 HPO 4 ) Reacting in an aqueous solution environment in which an oxidizing agent (such as hydrogen peroxide) exists to generate amorphous ferric phosphate precipitate, washing the obtained amorphous ferric phosphate precipitate, adding the washed amorphous ferric phosphate precipitate into a phosphoric acid solution, and carrying out crystal transformation at 85-100 ℃ to obtain ferric phosphate dihydrate crystals, wherein the ferric phosphate dihydrate crystals can be washed again to remove entrained free ions.
CN111816861A discloses a method for preparing a lithium iron phosphate positive electrode material by using waste lithium iron phosphate pole pieces. The method comprises the following steps: (1) Pretreating a waste lithium iron phosphate pole piece, and placing the waste lithium iron phosphate pole piece into a sagger; (2) Placing the sagger with the waste lithium iron phosphate pole piece in a sintering furnace, and sintering for the first time in an inert gas atmosphere; (3) Taking out the lithium iron phosphate pole piece, and sieving and separating the lithium iron phosphate positive pole material and the foil; (4) Crushing the lithium iron phosphate anode material, then placing the crushed material in a sagger, and sintering for the second time in an inert gas atmosphere; and (5) crushing the lithium iron phosphate anode material to obtain a finished product. But the purity of ferric phosphate in the lithium iron phosphate positive electrode material obtained by sintering for two times is lower.
CN110422831A discloses a method for recovering iron phosphate from lithium iron phosphate batteries, which comprises leaching a raw material with an acid solution, and adding an adsorbent for impurity removal, specifically sodium dihydrogen phosphate or activated carbon, into the leaching solution, wherein the two adsorbents have good impurity removal effects on insoluble small impurities, but have not ideal removal effects on soluble impurities.
CN110828887A discloses a recovery and regeneration method of waste lithium iron phosphate anode material and the obtained lithium iron phosphate anode material. The method comprises the following steps: 1) Separating the waste lithium iron phosphate positive pole piece, and removing the aluminum current collector to obtain a powdery lithium iron phosphate positive pole recycled material; 2) Adding a lithium source, an iron source and a phosphorus source, or adding a reducing agent, adding a binder for swelling the lithium iron phosphate positive electrode recovery material, and dissolving or dispersing an organic solvent for the lithium source, the iron source, the phosphorus source and the reducing agent, uniformly mixing the materials, and drying to obtain a lithium iron phosphate precursor; 3) Sintering in a reducing or inert gas atmosphere to obtain the repaired and regenerated lithium iron phosphate cathode material. The recycling and regenerating method needs to additionally add a lithium source, an iron source, a phosphorus source, a reducing agent and a binder, and has high recycling cost.
The method recovers the iron phosphate from the waste lithium iron phosphate battery material, and does not consider the further treatment of waste residues of the waste lithium iron phosphate positive electrode material after lithium extraction treatment. The method for regenerating the iron phosphate by using the waste lithium iron phosphate cathode material lithium extraction slag, which is simple in process flow, low in treatment cost and high in iron phosphate purity and is obtained by recycling, is developed.
Disclosure of Invention
In view of the problems in the prior art, the invention aims to provide a method for regenerating iron phosphate by using waste lithium iron phosphate cathode material lithium extraction slag, which designs a method for purifying and regenerating iron phosphate based on two-time heat preservation crystallization of iron phosphate by using the characteristic that the iron phosphate can be crystallized in a wider acid range, and realizes high-value and high-efficiency recovery of iron and phosphorus in the waste lithium iron phosphate cathode material lithium extraction slag.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a method for regenerating iron phosphate by extracting lithium slag from a waste lithium iron phosphate cathode material, which comprises the following steps:
(1) Mixing the waste lithium iron phosphate anode material lithium extraction slag and an acid solution, carrying out acid dissolution reaction, and carrying out solid-liquid separation to obtain a first liquid phase;
(2) Stirring and heating the first liquid phase, then preserving heat, and performing solid-liquid separation to obtain first iron phosphate and a first precipitation solution;
(3) After the first ferric phosphate is subjected to first calcination at the temperature of 100-800 ℃, repeating the step (1) and the step (2) to obtain second ferric phosphate and a second precipitation solution;
(4) And carrying out secondary calcination on the second iron phosphate at the temperature of 300-800 ℃ to obtain an iron phosphate product.
The method of the invention carries out the first calcination at 100-800 ℃ to promote the first ferric phosphate to generate crystal form transformation and generate the quartz phosphate type ferric phosphate which is easy to dissolve in acid; and carrying out secondary calcination at the temperature of 300-800 ℃ to promote second iron phosphate to be dehydrated to obtain an iron phosphate product, wherein the iron phosphate product can be used as anhydrous iron phosphate for batteries.
The solid-liquid separation is not limited in the present invention, and any method known to those skilled in the art that can be used for solid-liquid separation, such as filtration, sedimentation, centrifugation, or the like, can be used.
In the invention, step (3) and step (2) are repeated to obtain second iron phosphate and second precipitation solution, namely:
mixing the first ferric phosphate and an acid solution, carrying out acid dissolution reaction, and carrying out solid-liquid separation to obtain a second liquid phase;
and stirring and heating the second liquid phase, preserving heat, and performing solid-liquid separation to obtain second iron phosphate and a second precipitation solution.
In the invention, in the step (3), the steps (1) and (2) are repeated, and in the operation of obtaining the second iron phosphate and the second precipitation solution, the temperature of the acid dissolution reaction, the temperature for heat preservation and the time for heat preservation can be different from the conditions for obtaining the first iron phosphate and the first precipitation solution.
Preferably, the particle size of the waste lithium iron phosphate cathode material lithium extraction residue in the step (1) is 74 μm or less, for example, 74 μm, 70 μm, 60 μm, 40 μm, 25 μm, 10 μm or 5 μm, preferably 25 μm or less, and more preferably 10 μm or less.
The invention further preferably selects the particle size of the waste lithium iron phosphate anode material lithium extraction slag to be less than 74 μm, and has the advantage of improving the acid dissolution reaction rate and the acid dissolution reaction efficiency of the waste lithium iron phosphate anode material lithium extraction slag.
Preferably, the waste lithium iron phosphate cathode material lithium extraction slag is subjected to heat treatment before acid dissolution reaction.
Preferably, the atmosphere of the heat treatment comprises air and/or oxygen.
Preferably, the temperature of the heat treatment is 150 to 500 ℃, for example, 150 ℃, 200 ℃, 250 ℃, 300 ℃, 400 ℃ or 500 ℃.
According to the method, the waste lithium iron phosphate anode material lithium extraction slag is subjected to heat treatment at the temperature of 150-500 ℃, organic matters such as a binder (PVDF) and the like in the waste lithium iron phosphate anode material are removed, the dispersion of the waste lithium iron phosphate anode material lithium extraction slag is enhanced, and the efficiency of an acid dissolution reaction is improved.
Preferably, the heat treatment time is 2 to 7 hours, and may be, for example, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 5 hours, 6 hours, or 7 hours.
Preferably, the acid solution in step (1) includes any one of a sulfuric acid solution, a hydrochloric acid solution or a phosphoric acid solution or a combination of at least two of them, wherein typical but non-limiting combinations include a sulfuric acid solution and a hydrochloric acid solution, a sulfuric acid solution and a phosphoric acid solution, a hydrochloric acid solution and a phosphoric acid solution or a combination of a sulfuric acid solution, a hydrochloric acid solution and a phosphoric acid solution.
Preferably, H in the acid solution + The concentration is 0.2 to 12mol/L, and may be, for example, 0.2mol/L, 1.0mol/L, 1.2mol/L, 1.5mol/L, 2mol/L, 3mol/L, 4mol/L, 6mol/L, 8mol/L, 10mol/L or 12mol/L, and preferably 0.5 to 10mol/Lmol/L, more preferably 0.8 to 8mol/L.
Preferably, the solid-to-liquid ratio of the heat-treated lithium-extracted slag to the acid solution in step (2) is 1 (1 to 100) g/mL, and may be, for example, 1.
Preferably, the acid dissolution reaction temperature is 20 to 100 ℃, for example, 20 ℃, 30 ℃, 40 ℃, 50 ℃, 60 ℃, 80 ℃ or 100 ℃.
In the invention, the first precipitation solution in the step (2) is returned to the acid-soluble reaction in the step (1) for recycling, and the second precipitation solution is returned to the acid-soluble reaction of the first iron phosphate for recycling.
Preferably, the concentration of the phosphorus element in the first liquid phase and the second liquid phase in step (1) is 0.05 to 2.5mol/L, and may be, for example, 0.05mol/L, 0.1mol/L, 0.15mol/L, 0.2mol/L, 0.5mol/L, 1.0mol/L, 1.5mol/L, 2.0mol/L or 2.5mol/L.
Preferably, the concentration of the iron element in the first liquid phase and the second liquid phase in step (1) is 0.05 to 2.5mol/L, and may be, for example, 0.05mol/L, 0.1mol/L, 0.15mol/L, 0.2mol/L, 0.5mol/L, 1.0mol/L, 1.5mol/L, 2.0mol/L or 2.5mol/L.
The concentrations of phosphorus and iron in the first liquid phase and the second liquid phase are both 0.05-2.5 mol/L, because when the concentrations of phosphorus and iron in the first liquid phase and the second liquid phase are lower than 0.05mol/L, the iron phosphate cannot be obtained by crystallization in the subsequent stirring, heating and heat preservation processes; when the concentrations of phosphorus and iron in the first liquid phase and the second liquid phase are lower than 2.5mol/L, the phosphorus and iron can be subjected to self-precipitation, and iron phosphate cannot be obtained subsequently.
Preferably, the first liquid phase in step (2) is subjected to oxidation reaction before being stirred and heated.
In the present invention, it is further preferable that the first liquid phase is subjected to oxidation reaction before the temperature is raised by stirring, because Fe may be present in the first liquid phase 2+ Because the solubility of the ferric phosphate is lower than that of the ferrous phosphate, the oxidation reaction is needed to react Fe before stirring and heating 2+ Oxidation to Fe 3+ To facilitate the follow-upAnd reacting to obtain first iron phosphate.
Preferably, the oxidizing agent of the oxidation reaction comprises any one of hydrogen peroxide, oxygen, air, ozone, peroxymonosulfuric acid, peroxydisulfuric acid, ammonium persulfate, sodium persulfate, potassium persulfate, sodium hypochlorite, or sodium perchlorate, or a combination of at least two thereof, wherein typical but non-limiting combinations include a combination of hydrogen peroxide and oxygen, a combination of hydrogen peroxide and peroxymonosulfuric acid, a combination of peroxydisulfuric acid and ammonium persulfate, or a combination of hydrogen peroxide, air, and sodium hypochlorite.
Preferably, the addition amount of the oxidizing agent is Fe oxide 2+ The required amount of the oxidizing agent is 1.0 to 3.0 times the theoretical amount, and may be, for example, 1.0, 1.2, 1.5, 1.8, 2.0, 2.5 or 3.0 times.
Preferably, a precipitation aid is added to the first liquid phase after the oxidation reaction of step (2).
Preferably, the precipitation aid comprises anhydrous iron phosphate and/or iron phosphate dihydrate.
According to the invention, after the oxidation reaction in the step (2), a precipitation aid, namely anhydrous iron phosphate and/or ferric phosphate dihydrate, is added into the first liquid phase, so that the energy barrier of the iron phosphate in the heat preservation separation process is overcome, and the recovery rate and purity of the iron phosphate are improved.
The amount of the precipitation aid added is preferably 0.1 to 500g/L, and may be, for example, 0.1g/L, 1g/L, 5g/L, 10g/L, 20g/L, 50g/L, 100g/L, 200g/L, 300g/L or 500g/L, preferably 1 to 300g/L, and more preferably 1 to 200g/L.
The addition amount of the precipitation aid is 0.1-500 g/L, namely 0.1-500 g of precipitation aid is added in each liter of the first liquid phase.
Preferably, the precipitation aid added to the second liquid phase has a particle size of 0.02 to 6 μm, and may be, for example, 0.02 μm, 0.05 μm, 0.1 μm, 0.2 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 4 μm, 5 μm or 6 μm.
It is further preferred in the present invention that the precipitation aid added to the second liquid phase has a particle size of 0.02 to 6 μm to induce a particle size of the second iron phosphate solid that is close to the size requirements of the iron phosphate for the battery.
Preferably, the temperature for the incubation in step (2) is 40 to 200 ℃, for example 40 ℃, 50 ℃, 60 ℃, 80 ℃, 100 ℃, 150 ℃ or 200 ℃.
Preferably, the incubation time is 0.1 to 72 hours, for example, 0.1 hour, 0.3 hour, 1 hour, 3 hours, 5 hours, 10 hours, 20 hours, 30 hours, 50 hours or 72 hours.
Preferably, the atmosphere of the first calcination in step (3) comprises any one or a combination of at least two of air, oxygen, nitrogen, argon or helium, wherein typical but non-limiting combinations include a combination of air and oxygen, a combination of air and nitrogen, a combination of argon and oxygen or a combination of nitrogen, argon and oxygen.
Preferably, the time of the first calcination is 0.5 to 12 hours, and may be, for example, 0.5 hour, 1 hour, 2 hours, 3 hours, 5 hours, 8 hours, 10 hours, or 12 hours.
Preferably, the particle size of the second iron phosphate solid is treated to 1-6 μm, for example, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 4 μm, 5 μm or 6 μm before the second calcination in step (4).
According to the invention, the second iron phosphate is further preferably washed with water to remove impurities, and then the particle size of the second iron phosphate is treated to 1-6 μm.
In the present invention, it is further preferable that the iron phosphate for a battery is obtained by treating the particle size of the second iron phosphate to 1 to 6 μm before the second calcination in step (4).
Preferably, the treatment comprises any one of ball milling, sand milling or air flow milling.
Preferably, the time of the second calcination in step (4) is 0.15 to 12 hours, and may be, for example, 0.15 hour, 0.3 hour, 0.45 hour, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours or 12 hours.
The recitation of numerical ranges herein includes not only the above-recited values, but also any values between any of the above-recited numerical ranges not recited, and for brevity and clarity, is not intended to be exhaustive of the specific values encompassed within the range.
As a preferred technical scheme of the method, the method comprises the following steps:
(1) Waste lithium iron phosphate anode material lithium extraction slag with the particle size of less than 74 mu m is subjected to heat treatment for 2 to 7 hours at the temperature of between 150 and 500 ℃, and then the waste lithium iron phosphate anode material lithium extraction slag and H are mixed according to the solid-to-liquid ratio of 1 (1 to 100) g/mL + Acid solution with the concentration of 0.2-12 mol/L is subjected to acid dissolution reaction at the temperature of 20-100 ℃, and a first liquid phase is obtained through solid-liquid separation;
(2) Adding 0.1-500 g/L of precipitation aid into the first liquid phase, stirring, heating, keeping the temperature at 40-200 ℃ for 0.1-72 h, and performing solid-liquid separation to obtain first iron phosphate and first precipitation liquid;
(3) After the first ferric phosphate is subjected to first calcination for 0.5-12 h at the temperature of 100-800 ℃, repeating the steps (1) and (2) to obtain second ferric phosphate and a second precipitation solution;
(4) And carrying out secondary calcination on the second iron phosphate at the temperature of 300-800 ℃ for 0.15-12 h to obtain an iron phosphate product.
As a preferred technical scheme of the method, the method comprises the following steps:
(1) Waste lithium iron phosphate anode material lithium extraction slag with the particle size of less than 74 mu m is subjected to heat treatment for 2 to 7 hours at the temperature of between 150 and 500 ℃, and then the waste lithium iron phosphate anode material lithium extraction slag and H are mixed according to the solid-to-liquid ratio of 1 (1 to 100) g/mL + Acid solution with the concentration of 0.2-12 mol/L is subjected to acid dissolution reaction at the temperature of 20-100 ℃, and a first liquid phase is obtained through solid-liquid separation;
(2) Adding 0.1-500 g/L of precipitation aid into the first liquid phase, stirring, heating, keeping the temperature at 40-200 ℃ for 0.1-72 h, and performing solid-liquid separation to obtain first iron phosphate and first precipitation liquid;
(3) After the first ferric phosphate is subjected to first calcination at the temperature of 100-800 ℃ for 0.5-12H, mixing the first ferric phosphate and H according to the solid-to-liquid ratio of 1 (1-100) g/mL + Acid solution with the concentration of 0.2-12 mol/L is subjected to acid dissolution reaction at the temperature of 20-100 ℃, and a second liquid phase is obtained through solid-liquid separation; adding to the second liquid phaseStirring and heating 0.1-500 g/L of precipitation aid, keeping the temperature at 40-200 ℃ for 0.1-72 h, and performing solid-liquid separation to obtain second iron phosphate and second precipitation liquid;
(4) And carrying out secondary calcination on the second iron phosphate at the temperature of 300-800 ℃ for 0.15-12 h to obtain an iron phosphate product.
Compared with the prior art, the invention has the beneficial effects that:
(1) The method for regenerating the iron phosphate by using the waste lithium iron phosphate cathode material lithium extraction residue has a good acid dissolution effect on the waste lithium iron phosphate cathode material lithium extraction residue, the recovery rate of the iron phosphate product can reach more than 85.5%, the purity of the iron phosphate product meets or is even better than the standard of iron phosphate for batteries (HG/T4701-2014), and the iron phosphate product can be used as the iron phosphate for the batteries.
(2) The method for regenerating iron phosphate by extracting lithium slag from the waste lithium iron phosphate cathode material, provided by the invention, has the advantages of simple treatment process, simplicity in operation, less waste generated after treatment and small influence on environment.
Drawings
Fig. 1 is a process flow chart of a method for regenerating iron phosphate from lithium extraction slag of a waste lithium iron phosphate positive electrode material provided by the invention.
Detailed Description
The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.
The present invention is described in further detail below. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.
The invention provides a method for regenerating iron phosphate by extracting lithium slag from a waste lithium iron phosphate cathode material, which has a process flow chart shown in figure 1 and comprises the following steps:
(1) Waste lithium iron phosphate anode material lithium extraction slag with the particle size of less than 74 mu m is subjected to heat treatment for 2 to 7 hours at the temperature of between 150 and 500 ℃, and then the waste lithium iron phosphate anode material lithium extraction slag and H are mixed according to the solid-to-liquid ratio of 1 (1 to 100) g/mL + Acid solution with the concentration of 0.2-12 mol/L is carried out at the temperature of 20-100 DEG CCarrying out acid dissolution reaction, and carrying out solid-liquid separation to obtain a first liquid phase;
(2) Adding 0.1-500 g/L of precipitation aid into the first liquid phase, stirring, heating, keeping the temperature at 40-200 ℃ for 0.1-72 h, and performing solid-liquid separation to obtain first iron phosphate and first precipitation liquid;
(3) After the first ferric phosphate is subjected to first calcination at the temperature of 100-800 ℃ for 0.5-12H, mixing the first ferric phosphate and an acid solution with the H + concentration of 0.2-12 mol/L according to the solid-to-liquid ratio of 1 (1-100) g/mL, carrying out acid dissolution reaction at the temperature of 20-100 ℃, and carrying out solid-liquid separation to obtain a second liquid phase; adding 0.1-500 g/L of precipitation aid into the second liquid phase, stirring, heating, keeping the temperature at 40-200 ℃ for 0.1-72 h, and performing solid-liquid separation to obtain second iron phosphate and a second precipitation liquid;
(4) And carrying out secondary calcination on the second iron phosphate at the temperature of 300-800 ℃ for 0.15-12 h to obtain an iron phosphate product.
Example 1
The embodiment provides a method for regenerating iron phosphate by extracting lithium slag from a waste lithium iron phosphate cathode material, which comprises the following steps:
(1) Carrying out heat treatment on waste lithium iron phosphate cathode material lithium extraction slag with the average particle size of 50 microns at 400 ℃ in an air atmosphere for 5h to obtain heat-treated lithium extraction slag;
(2) Weighing 100g of heat-treated lithium extraction slag and 120mL of H + Mixing sulfuric acid solutions with the concentration of 10mol/L, carrying out acid dissolution reaction at the temperature of 20 ℃, and filtering to obtain a first liquid phase; adding deionized water into the first liquid phase, and controlling the concentrations of the iron element and the phosphorus element to be 1.0mol/L; the first liquid phase is free of Fe 2+ ；
(3) Adding 50g/L of anhydrous iron phosphate with an average particle size of 3 mu m to the first liquid phase; stirring and heating the first liquid phase, then preserving heat for 12 hours at the temperature of 90 ℃, and filtering to obtain first iron phosphate and a first precipitation solution; the addition amount of the ammonium persulfate is Fe oxide 2+ 1.0 times the theoretical amount of oxidant required;
(4) The first phosphorAfter iron phosphate is subjected to first calcination for 2 hours at the temperature of 300 ℃ in an air atmosphere, mixing calcined first iron phosphate and H according to a solid-liquid ratio of 1 + Carrying out acid dissolution reaction on a 3mol/L sulfuric acid solution at the temperature of 60 ℃, and obtaining a second liquid phase after the solution is clarified; the concentration of the iron element and the concentration of the phosphorus element in the second liquid phase are both 1.324mol/L; adding 10g/L of anhydrous iron phosphate into the second liquid phase, transferring the second liquid phase into a precipitation reactor, stirring, heating, keeping the temperature at 120 ℃ for 4 hours, and filtering to obtain second iron phosphate and a second precipitation liquid;
(5) And after washing, ball-milling the second iron phosphate until the average particle size is 3 mu m, and carrying out second calcination at the temperature of 500 ℃ for 3h to obtain an iron phosphate product.
Example 2
The embodiment provides a method for regenerating iron phosphate by extracting lithium slag from a waste lithium iron phosphate cathode material, which comprises the following steps:
(1) Carrying out heat treatment on waste lithium iron phosphate cathode material lithium extraction slag with the average particle size of 30 mu m at the temperature of 300 ℃ in an oxygen atmosphere for 7h to obtain heat-treated lithium extraction slag;
(2) Weighing 100g of heat-treated lithium extraction slag and 1000mL of H + Mixing sulfuric acid solutions with the concentration of 3mol/L, carrying out acid dissolution reaction at the temperature of 60 ℃, and filtering to obtain a first liquid phase; the concentrations of the iron element and the phosphorus element in the first liquid phase are both 0.5mol/L; the first liquid phase is free of Fe 2+ ；
(3) Adding 50g/L of ferric phosphate dihydrate with the average particle size of 0.2 mu m to the first liquid phase; stirring and heating the first liquid phase, preserving heat for 4 hours at the temperature of 100 ℃, and filtering to obtain first iron phosphate and first precipitation liquid;
(4) After the first iron phosphate is subjected to first calcination for 1H at 500 ℃ in an air atmosphere, mixing the calcined first iron phosphate and H according to a solid-to-liquid ratio of 1 + Carrying out acid dissolution reaction on a sulfuric acid solution with the concentration of 0.2mol/L at the temperature of 70 ℃, and obtaining a second liquid phase after the solution is clarified; the concentrations of the iron element and the phosphorus element in the second liquid phase are both 0.05mol/L; adding 0.1g/L of anhydrous iron phosphate into the second liquid phase, transferring the second liquid phase into a precipitation reactor, stirring, heating, keeping the temperature at 160 ℃ for 6 hours, and filtering to obtain second iron phosphate and a second precipitation solution;
(5) And after washing, ball-milling the second iron phosphate until the average particle size is 1 mu m, and carrying out second calcination at the temperature of 800 ℃ for 2h to obtain an iron phosphate product.
Example 3
The embodiment provides a method for regenerating iron phosphate by extracting lithium slag from a waste lithium iron phosphate cathode material, which comprises the following steps:
(1) Weighing 10g of waste lithium iron phosphate cathode material lithium extraction slag with the average particle size of 74 mu m and 100mL of H + Mixing sulfuric acid solutions with the concentration of 1.5mol/L, carrying out acid dissolution reaction at the temperature of 40 ℃, and filtering to obtain a first liquid phase; the concentrations of the iron element and the phosphorus element in the first liquid phase are both 0.5mol/L; fe in the first liquid phase 2+ The concentration is 2.5g/L;
(2) After the first liquid phase is subjected to potassium sulfate oxidation reaction, 250g/L of ferric phosphate dihydrate with the average particle size of 6 mu m is added; stirring and heating the first liquid phase, preserving heat for 5 hours at the temperature of 110 ℃, and filtering to obtain first iron phosphate and first precipitation liquid; the addition amount of the potassium persulfate is Fe oxide 2+ 1.5 times the theoretical amount of oxidant required;
(3) The first iron phosphate is subjected to first calcination for 4 hours in an oxygen atmosphere at the temperature of 200 ℃, and then the calcined first iron phosphate and H are mixed according to the solid-to-liquid ratio of 1 + Carrying out acid dissolution reaction on a 1.2mol/L sulfuric acid solution at the temperature of 90 ℃, and obtaining a second liquid phase after the solution is clarified; the concentrations of the iron element and the phosphorus element in the second liquid phase are both 0.66mol/L; adding 0.1g/L of ferric phosphate dihydrate into the second liquid phase, transferring the second liquid phase into a precipitation reactor, stirring and heating, then preserving heat for 0.1h at the temperature of 200 ℃, and filtering to obtain second ferric phosphate and a second precipitation liquid;
(4) And (3) after washing the second iron phosphate, ball-milling the second iron phosphate until the average particle size is 6 mu m, and carrying out second calcination at the temperature of 800 ℃ for 0.15h to obtain an iron phosphate product.
Example 4
The embodiment provides a method for regenerating iron phosphate by extracting lithium slag from a waste lithium iron phosphate cathode material, which comprises the following steps:
(1) Weighing 100g of waste lithium iron phosphate cathode material lithium extraction slag with the average particle size of 20 mu m and 100mL of H + Mixing sulfuric acid solutions with the concentration of 8mol/L, carrying out acid dissolution reaction at the temperature of 90 ℃, and filtering to obtain a first liquid phase; adding deionized water into the first liquid phase, and controlling the concentrations of the iron element and the phosphorus element to be 1.5mol/L; fe in the first liquid phase 2+ The concentration is 4g/L;
(2) Adding 250g/L anhydrous iron phosphate with the average particle size of 4 mu m after the first liquid phase is subjected to oxidation-oxidation reaction; stirring and heating the first liquid phase, then preserving heat for 0.1h at the temperature of 200 ℃, and filtering to obtain first iron phosphate and a first precipitation solution; the addition amount of the hydrogen peroxide is Fe oxide 2+ 2.0 times the theoretical amount of oxidant required;
(3) After the first iron phosphate is subjected to first calcination for 12 hours at the temperature of 100 ℃ in a nitrogen atmosphere, mixing the calcined first iron phosphate and H according to a solid-to-liquid ratio of 1 + Carrying out acid dissolution reaction on a sulfuric acid solution with the concentration of 8mol/L at the temperature of 20 ℃, and obtaining a second liquid phase after the solution is clarified; adding a proper amount of deionized water, and controlling the concentration of iron and phosphorus to be 2.0mol/L; adding 180g/L of ferric phosphate dihydrate into the second liquid phase, transferring the second liquid phase into a precipitation reactor, stirring and heating the second liquid phase, preserving the temperature for 48 hours at the temperature of 60 ℃, and filtering the mixture to obtain second ferric phosphate and a second precipitation solution;
(4) And after washing, ball-milling the second iron phosphate until the average particle size is 4 mu m, and calcining at 300 ℃ for 9h to obtain an iron phosphate product.
Example 5
The embodiment provides a method for regenerating iron phosphate by extracting lithium slag from a waste lithium iron phosphate cathode material, which comprises the following steps:
(1) Weighing 100g of waste lithium iron phosphate cathode material lithium extraction slag with the average particle size of 10 mu m and 100mL of H + Mixing sulfuric acid solutions with the concentration of 10mol/L, carrying out acid dissolution reaction at the temperature of 20 ℃, and filtering to obtain a first liquid phase; adding deionized water into the first liquid phase, and controlling the concentrations of the iron element and the phosphorus element to be 1.0mol/L; fe in the first liquid phase 2+ The concentration is 3g/L;
(2) After the first liquid phase is oxidized by ammonium sulfate, 200g/L of dihydrate ferric phosphate with the average particle size of 3 mu m is added; stirring and heating the first liquid phase, then preserving heat for 12 hours at the temperature of 90 ℃, and filtering to obtain first iron phosphate and a first precipitation solution; the addition amount of the ammonium persulfate is Fe oxide 2+ 1.0 times the theoretical amount of oxidant required;
(3) The first iron phosphate is subjected to first calcination for 2 hours in an air atmosphere at the temperature of 300 ℃, and then the calcined first iron phosphate and H are mixed according to a solid-to-liquid ratio of 1 + Carrying out acid dissolution reaction on a hydrochloric acid solution with the concentration of 1.0mol/L at the temperature of 60 ℃, and obtaining a second liquid phase after the solution is clarified; the concentrations of the iron element and the phosphorus element in the second liquid phase are both 0.33mol/L; adding 100g/L of ferric phosphate dihydrate into the second liquid phase, transferring the second liquid phase into a precipitation reactor, stirring and heating, preserving the temperature for 15 hours at the temperature of 100 ℃, and filtering to obtain second ferric phosphate and a second precipitation solution;
(4) And after washing, ball-milling the second iron phosphate until the average particle size is 3 mu m, and carrying out second calcination at the temperature of 500 ℃ for 3h to obtain an iron phosphate product.
Example 6
The embodiment provides a method for regenerating iron phosphate by extracting lithium slag from a waste lithium iron phosphate cathode material, which comprises the following steps:
(1) Carrying out heat treatment on waste lithium iron phosphate cathode material lithium extraction slag with the average particle size of 25 mu m at 400 ℃ in an air atmosphere for 5h to obtain heat-treated lithium extraction slag;
(2) 100g of heat-treated lithium extraction slag and 100mL of H are weighed + Mixing with 10mol/L sulfuric acid solution, and processing at 20 deg.CCarrying out acid dissolution reaction under the condition, and filtering to obtain a first liquid phase; adding deionized water into the first liquid phase, and controlling the concentrations of both iron element and phosphorus element at 1.0mol/L; the first liquid phase is free of Fe 2+ ；
(3) Adding 200g/L of anhydrous iron phosphate with an average particle size of 3 mu m to the first liquid phase; stirring and heating the first liquid phase, preserving the heat for 12 hours at the temperature of 90 ℃, and filtering to obtain first iron phosphate and first precipitation liquid;
(4) After the first iron phosphate is subjected to first calcination for 2 hours in an air atmosphere at the temperature of 300 ℃, mixing the calcined first iron phosphate and H according to a solid-liquid ratio of 1 + Carrying out acid dissolution reaction on a phosphoric acid solution with the concentration of 4.5mol/L at the temperature of 80 ℃, and obtaining a second liquid phase after the solution is clarified; the concentrations of the iron element and the phosphorus element in the second liquid phase are both 1.3mol/L; adding 10g/L of ferric phosphate dihydrate into the second liquid phase, transferring the second liquid phase into a precipitation reactor, stirring, heating, keeping the temperature at 100 ℃ for 15 hours, and filtering to obtain second ferric phosphate and a second precipitation liquid;
(5) And after washing, ball-milling the second iron phosphate until the average particle size is 3 mu m, and carrying out second calcination at the temperature of 500 ℃ for 3h to obtain an iron phosphate product.
Example 7
The embodiment provides a method for regenerating iron phosphate by extracting lithium slag from a waste lithium iron phosphate cathode material, which comprises the following steps:
(1) Carrying out heat treatment on the waste lithium iron phosphate cathode material lithium extraction slag with the average particle size of 30 microns at the temperature of 150 ℃ for 2h to obtain heat-treated lithium extraction slag;
(2) Weighing 10g of heat-treated lithium extraction slag and 10mL of H + Mixing sulfuric acid solutions with the concentration of 12.0mol/L, performing acid dissolution reaction at the temperature of 100 ℃, and filtering to obtain a first liquid phase; the concentrations of the iron element and the phosphorus element in the first liquid phase are both 4mol/L; fe in the first liquid phase 2+ The concentration is 0;
(3) Adding 500g/L of anhydrous iron phosphate having an average particle size of 1 μm to the first liquid phase; stirring and heating the first liquid phase, then preserving heat for 72 hours at the temperature of 40 ℃, and filtering to obtain first iron phosphate and a first precipitation solution;
(4) After the first iron phosphate is subjected to first calcination for 0.5H at 800 ℃ in a nitrogen atmosphere, mixing the calcined first iron phosphate and H according to a solid-to-liquid ratio of 1 + Carrying out acid dissolution reaction on an acid solution with the concentration of 12mol/L at the temperature of 100 ℃, and obtaining a second liquid phase after the solution is clarified; the concentrations of the iron element and the phosphorus element in the second liquid phase are both 3.3mol/L; adding 500g/L of ferric phosphate dihydrate into the second liquid phase, transferring the second liquid phase into a precipitation reactor, stirring and heating, preserving the temperature for 72 hours at the temperature of 40 ℃, and filtering to obtain second ferric phosphate and a second precipitation solution;
(5) And after washing, ball-milling the second iron phosphate until the average particle size is 6 mu m, and carrying out second calcination at the temperature of 300 ℃ for 12h to obtain an iron phosphate product.
Example 8
The embodiment provides a method for regenerating iron phosphate from waste lithium iron phosphate cathode material lithium extraction slag, which is the same as the embodiment 1 except that no anhydrous iron phosphate is added in the step (3).
Example 9
The embodiment provides a method for regenerating iron phosphate by extracting lithium slag from a waste lithium iron phosphate cathode material, which is the same as the embodiment 3 except that no potassium persulfate is added in the step (2).
Comparative example 1
The method is the same as that in the example 1 except that the first calcining temperature in the step (4) is 50 ℃.
Comparative example 2
The method is the same as that in the example 1 except that the first calcination temperature in the step (4) is 850 ℃.
Comparative example 3
The comparative example provides a method for regenerating iron phosphate from waste lithium iron phosphate cathode material lithium extraction slag, which is the same as that in example 1 except that the second calcination temperature in step (5) is 250 ℃.
Comparative example 4
The method is the same as that in the example 1 except that the second calcination temperature in the step (5) is 850 ℃.
The impurity contents of the iron phosphate products of the above examples and comparative examples were measured using an ICP-5300 inductively coupled plasma spectrometer, the recovery rate of the iron phosphate product was calculated by measuring the iron phosphorus concentration in the raffinate, and the purity of the iron phosphate product was calculated by measuring the iron phosphorus concentration and the impurity concentration in the ICP test product, with the results shown in table 1.
TABLE 1
| Recovery (%) | Purity (%) | |
| Example 1 | 95.2％ | 99.93％ |
| Example 2 | 96.1％ | 99.95％ |
| Example 3 | 96.3％ | 99.90％ |
| Example 4 | 95.5％ | 99.92％ |
| Example 5 | 94.0％ | 99.99％ |
| Example 6 | 92.2％ | 99.99％ |
| Example 7 | 91.2％ | 99.90％ |
| Example 8 | 85.5％ | 99.92％ |
| Example 9 | 90.1％ | 99.90％ |
| Comparative example 1 | 52.0％ | 99.91％ |
| Comparative example 2 | 84.3％ | 99.92％ |
| Comparative example 3 | 95.2％ | 99.83％ |
| Comparative example 4 | 95.2％ | 99.93％ |
From table 1, the following points can be seen:
(1) It can be seen from the comprehensive examples 1 to 9 that the recovery rate of the iron phosphate product obtained by the method for regenerating iron phosphate from the waste lithium iron phosphate cathode material lithium extraction slag provided by the invention can reach more than 85.5%, and the purity can reach more than 99.90%;
(2) It can be seen from the combination of example 1 and example 8 that, when anhydrous ferric phosphate is added in step (3) of example 1, compared with the case that anhydrous ferric phosphate is not added in step (3) of example 8, the recovery rate of the ferric phosphate product in example 1 is 95.2%, the purity of the ferric phosphate product is 99.93%, the recovery rate of the ferric phosphate product in example 8 is greatly reduced to 85.5%, and the purity of the ferric phosphate product is 99.92%; therefore, the method further preferably adds the precipitation aid into the first liquid phase, so that the recovery rate of the iron phosphate product can be obviously improved;
(3) By combining example 3 with example 9, it can be seen that the addition of potassium persulfate in step (2) of example 3 results in a recovery rate of iron phosphate product of 96.3% and a purity of iron phosphate product of 99.90% in example 3, and a recovery rate of iron phosphate product of 90.1% in example 9, compared to the addition of potassium persulfate in step (2) of example 9, and the purity of iron phosphate product is the same as that of example 3; therefore, the first liquid phase is preferably subjected to oxidation reaction before being stirred and heated, and Fe in the first liquid phase is added 2+ Oxidation to Fe 3+ The recovery rate of the iron phosphate product can be obviously improved;
(4) As can be seen by combining example 1 and comparative examples 1 to 2, the temperature of the first calcination in step (4) of example 1 was 300 ℃, and the recovery rates of the iron phosphate products in comparative examples 1 to 2 were greatly reduced as compared to 50 ℃ and 850 ℃ respectively, in step (4) of comparative examples 1 to 2, the recovery rate of the iron phosphate product in comparative example 1 was only 52.0%, the recovery rate of the iron phosphate product in comparative example 2 was only 84.3%, and the purity of the iron phosphate product in comparative examples 1 to 2 was slightly reduced as compared to example 1, and was 99.91% and 99.92%, respectively; therefore, the temperature of the first calcination is controlled to be 100-800 ℃, the first iron phosphate is promoted to generate crystal form transformation, and the quartz phosphate type iron phosphate which is easily dissolved in acid is generated, so that the recovery rate of the iron phosphate product is greatly improved;
(5) As can be seen by combining example 1 and comparative examples 3 to 4, the temperature of the second calcination in step (5) of example 1 was 500 ℃, and the recovery rate of the iron phosphate product in comparative examples 3 to 4 was the same as that of example 1, compared to the temperatures of 250 ℃ and 850 ℃ in step (5) of comparative examples 3 to 4, respectively, and the purity of the iron phosphate product in comparative example 3 was slightly decreased to 99.83% compared to example 1, but the second calcination temperature had a great influence on the particle size and crystallinity of the obtained iron phosphate product, and the average particle size of the iron phosphate product in example 1 was 4 μm and the crystallinity was good, while the average particle size of the iron phosphate product in comparative example 3 was also 4 μm and the crystallinity was low, and the crystallinity of the iron phosphate product in comparative example 4 was good but the average particle size was 12 μm; therefore, the temperature of the second calcination is controlled to be 300-800 ℃, and the average particle size of the obtained iron phosphate product meets the standard of iron phosphate for batteries.
In conclusion, the recovery rate of the iron phosphate product obtained by the method for regenerating iron phosphate by extracting lithium slag from the waste lithium iron phosphate cathode material can reach more than 85.5%, the purity of the iron phosphate product meets or is even better than the standard of iron phosphate for batteries (HG/T4701-2014), and the iron phosphate product can be used as the iron phosphate for the batteries.
The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.
Claims (10)
1. A method for regenerating iron phosphate from waste lithium iron phosphate anode material lithium extraction slag is characterized by comprising the following steps:
(1) Mixing the waste lithium iron phosphate anode material lithium extraction slag and an acid solution, carrying out acid dissolution reaction, and carrying out solid-liquid separation to obtain a first liquid phase;
(2) Stirring and heating the first liquid phase, then preserving heat, and performing solid-liquid separation to obtain first iron phosphate and first precipitation liquid;
(3) After the first ferric phosphate is subjected to first calcination at the temperature of 100-800 ℃, repeating the step (1) and the step (2) to obtain second ferric phosphate and a second precipitation solution;
(4) And carrying out secondary calcination on the second iron phosphate at the temperature of 300-800 ℃ to obtain an iron phosphate product.
2. The method according to claim 1, wherein the particle size of the waste lithium iron phosphate positive electrode material lithium extraction residue in the step (1) is 74 μm or less, preferably 25 μm or less, and more preferably 10 μm or less;
preferably, the waste lithium iron phosphate cathode material lithium extraction slag is subjected to heat treatment before acid dissolution reaction;
preferably, the atmosphere of the heat treatment comprises air and/or oxygen;
preferably, the temperature of the heat treatment is 150-500 ℃;
preferably, the time of the heat treatment is 2 to 7 hours.
3. The method according to claim 1 or 2, wherein the acid solution of step (1) comprises any one of a sulfuric acid solution, a hydrochloric acid solution or a phosphoric acid solution or a combination of at least two thereof;
preferably, H in the acid solution + The concentration is 0.2 to 12mol/L, preferably 0.5 to 10mol/L, and more preferably 0.8 to 8mol/L.
4. The method according to any one of claims 1 to 3, wherein the solid-to-liquid ratio of the lithium extraction residue of the waste lithium iron phosphate cathode material in the step (1) to the acid solution is 1 (1-100) g/mL;
preferably, the temperature of the acid dissolution reaction is 20 to 100 ℃.
5. The method according to any one of claims 1 to 4, wherein the first liquid phase in step (2) is subjected to an oxidation reaction before being stirred and heated;
preferably, the oxidizing agent of the oxidation reaction comprises any one of hydrogen peroxide, oxygen, air, ozone, peroxymonosulfuric acid, peroxydisulfuric acid, ammonium persulfate, sodium persulfate, potassium persulfate, sodium hypochlorite or sodium perchlorate or a combination of at least two of the two;
preferably, the addition amount of the oxidizing agent is Fe oxide 2+ 1.0 to 3.0 times the theoretical amount of oxidant required.
6. The process according to any one of claims 1 to 5, wherein, after the oxidation reaction of step (2), a precipitation aid is added to the first liquid phase;
preferably, the precipitation aid comprises anhydrous iron phosphate and/or iron phosphate dihydrate;
preferably, the addition amount of the precipitation aid is 0.1-500 g/L.
7. The method according to any one of claims 1 to 6, wherein the temperature for the incubation in step (2) is 40 to 200 ℃;
preferably, the time for heat preservation is 0.1-72 h.
8. The method according to any one of claims 1 to 7, wherein the atmosphere of the first calcination in step (3) comprises any one or a combination of at least two of air, oxygen, nitrogen, argon or helium;
preferably, the time of the first calcination is 0.5 to 12 hours.
9. The process according to any one of claims 1 to 8, wherein the time of the second calcination in step (4) is 0.15 to 12 hours.
10. The method according to any one of claims 1 to 9, characterized in that it comprises the steps of:
(1) Waste lithium iron phosphate anode material lithium extraction slag with the particle size of less than 74 mu m is subjected to heat treatment for 2 to 7 hours at the temperature of between 150 and 500 ℃, and then the waste lithium iron phosphate anode material lithium extraction slag and H are mixed according to the solid-to-liquid ratio of 1 (1 to 100) g/mL + Acid solution with the concentration of 0.2-12 mol/L is subjected to acid dissolution reaction at the temperature of 20-100 ℃, and a first liquid phase is obtained through solid-liquid separation;
(2) Adding 0.1-500 g/L of precipitation aid into the first liquid phase, stirring, heating, keeping the temperature at 40-200 ℃ for 0.1-72 h, and performing solid-liquid separation to obtain first iron phosphate and first precipitation liquid;
(3) After the first ferric phosphate is subjected to first calcination at the temperature of 100-800 ℃ for 0.5-12 h, repeating the steps (1) and (2) to obtain second ferric phosphate and a second precipitation solution;
(4) And carrying out secondary calcination on the second iron phosphate at the temperature of 300-800 ℃ for 0.15-12 h to obtain an iron phosphate product.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110806701.4A CN115611251B (en) | 2021-07-16 | 2021-07-16 | Method for regenerating ferric phosphate by extracting lithium slag from waste lithium iron phosphate anode material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110806701.4A CN115611251B (en) | 2021-07-16 | 2021-07-16 | Method for regenerating ferric phosphate by extracting lithium slag from waste lithium iron phosphate anode material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115611251A true CN115611251A (en) | 2023-01-17 |
| CN115611251B CN115611251B (en) | 2024-03-26 |
Family
ID=84856247
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110806701.4A Active CN115611251B (en) | 2021-07-16 | 2021-07-16 | Method for regenerating ferric phosphate by extracting lithium slag from waste lithium iron phosphate anode material |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115611251B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101439427B1 (en) * | 2013-03-14 | 2014-09-11 | 한국과학기술연구원 | Recycling method of olivine-based cathode material for lithium secondary battery, cathode material fabricated therefrom, and cathode and lithium secondary battery having the same |
| WO2020134773A1 (en) * | 2018-12-29 | 2020-07-02 | 宁德时代新能源科技股份有限公司 | Method for recovering and preparing lithium iron phosphate cathode material |
| CN111646447A (en) * | 2020-06-17 | 2020-09-11 | 中国科学院宁波材料技术与工程研究所 | Method for recovering iron phosphate from iron-phosphorus slag after lithium extraction of lithium iron phosphate lithium battery |
| CN112499609A (en) * | 2020-12-03 | 2021-03-16 | 广东邦普循环科技有限公司 | Method for preparing iron phosphate by using waste lithium iron phosphate anode powder lithium extraction slag and application |
| CN112520718A (en) * | 2020-12-04 | 2021-03-19 | 南昌航空大学 | Method for selectively recovering battery-grade iron phosphate from acid leaching solution of lithium extraction slag |
-
2021
- 2021-07-16 CN CN202110806701.4A patent/CN115611251B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101439427B1 (en) * | 2013-03-14 | 2014-09-11 | 한국과학기술연구원 | Recycling method of olivine-based cathode material for lithium secondary battery, cathode material fabricated therefrom, and cathode and lithium secondary battery having the same |
| WO2020134773A1 (en) * | 2018-12-29 | 2020-07-02 | 宁德时代新能源科技股份有限公司 | Method for recovering and preparing lithium iron phosphate cathode material |
| CN111646447A (en) * | 2020-06-17 | 2020-09-11 | 中国科学院宁波材料技术与工程研究所 | Method for recovering iron phosphate from iron-phosphorus slag after lithium extraction of lithium iron phosphate lithium battery |
| CN112499609A (en) * | 2020-12-03 | 2021-03-16 | 广东邦普循环科技有限公司 | Method for preparing iron phosphate by using waste lithium iron phosphate anode powder lithium extraction slag and application |
| CN112520718A (en) * | 2020-12-04 | 2021-03-19 | 南昌航空大学 | Method for selectively recovering battery-grade iron phosphate from acid leaching solution of lithium extraction slag |
Non-Patent Citations (1)
| Title |
|---|
| 万青珂;张洋;郑诗礼;张盈;王晓健;娄文博;JAN J.WEIGAND;MARCO WENZEL;: "废旧磷酸铁锂正极粉磷酸浸出过程的优化及宏观动力学", 化工进展, no. 06, pages 2495 - 2502 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115611251B (en) | 2024-03-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113061723B (en) | Method for recovering lithium from waste lithium iron phosphate batteries and preparing iron phosphate | |
| CN112897492B (en) | Method for regenerating and recycling high-impurity lithium iron phosphate waste powder | |
| CN107739830A (en) | A kind of recovery method of positive material of waste lithium iron phosphate | |
| CN110343864B (en) | Method for recovering lithium and cobalt in waste electrode material by microwave roasting assistance | |
| CN110474123B (en) | Comprehensive recovery method of waste lithium iron phosphate battery positive electrode material | |
| CN111129632A (en) | Method for recycling anode and cathode mixed materials of waste ternary lithium ion battery | |
| CN114195112A (en) | Recovery method of waste lithium iron phosphate battery | |
| CN111392750A (en) | Method for removing impurities and recovering lithium from waste lithium ion batteries | |
| CN109179359A (en) | A method of extracting lithium and ferric phosphate from LiFePO4 waste material | |
| CN115432681B (en) | Regeneration process of waste lithium iron phosphate battery anode material | |
| CN113912033A (en) | Method for recycling anode and cathode mixed powder of waste lithium iron phosphate battery with pre-positioned lithium extraction | |
| CN113415813A (en) | Method for recovering lithium nickel cobalt manganese from waste ternary battery material | |
| CN114709504A (en) | Clean recovery method of waste lithium iron phosphate anode material | |
| WO2023029573A1 (en) | Method for extracting lithium from waste lithium battery | |
| CN114597399A (en) | Preparation method and application of vanadium iron sodium phosphate material | |
| CN114317968A (en) | Recycling method and application of waste lithium iron phosphate battery | |
| CN115893346A (en) | Method for recovering and preparing battery-grade iron phosphate after lithium extraction of waste lithium iron phosphate cathode material | |
| CN114604836A (en) | Recovery method for waste lithium iron phosphate positive and negative mixed powder through ultrasonic high-energy oxygen treatment | |
| CN112342383B (en) | Method for separating and recovering nickel, cobalt, manganese and lithium in ternary waste | |
| CN113816353A (en) | Method for removing aluminum in acid leaching solution of waste lithium iron phosphate battery through iron-aluminum coprecipitation | |
| CN115448335B (en) | Recycling method of waste lithium iron manganese phosphate battery | |
| CN115784188A (en) | Method for recycling and preparing battery-grade iron phosphate | |
| CN115611251B (en) | Method for regenerating ferric phosphate by extracting lithium slag from waste lithium iron phosphate anode material | |
| CN115216649B (en) | Method for preparing vanadium dioxide battery material by using waste vanadium-titanium-based SCR catalyst | |
| CN115535987B (en) | Method for recycling valuable elements from lithium iron manganese phosphate positive electrode waste |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |