CN116770096A - Method for recycling lithium from lithium iron phosphate waste - Google Patents
Method for recycling lithium from lithium iron phosphate waste Download PDFInfo
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- CN116770096A CN116770096A CN202310667290.4A CN202310667290A CN116770096A CN 116770096 A CN116770096 A CN 116770096A CN 202310667290 A CN202310667290 A CN 202310667290A CN 116770096 A CN116770096 A CN 116770096A
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- lithium
- iron phosphate
- lithium iron
- phosphate waste
- partial pressure
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- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 83
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 79
- 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 65
- 238000000034 method Methods 0.000 title claims abstract description 62
- 239000002699 waste material Substances 0.000 title claims abstract description 49
- 238000004064 recycling Methods 0.000 title abstract description 6
- 239000002253 acid Substances 0.000 claims abstract description 30
- 238000006243 chemical reaction Methods 0.000 claims abstract description 27
- 238000002386 leaching Methods 0.000 claims abstract description 27
- 230000001590 oxidative effect Effects 0.000 claims abstract description 21
- 239000007864 aqueous solution Substances 0.000 claims abstract description 18
- 239000007788 liquid Substances 0.000 claims abstract description 10
- 239000002002 slurry Substances 0.000 claims abstract description 10
- 238000000926 separation method Methods 0.000 claims abstract description 5
- 239000007789 gas Substances 0.000 claims description 41
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 16
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 claims description 16
- 229910052760 oxygen Inorganic materials 0.000 claims description 13
- 239000000243 solution Substances 0.000 claims description 12
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 11
- 239000001301 oxygen Substances 0.000 claims description 11
- 239000007787 solid Substances 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 10
- 239000001569 carbon dioxide Substances 0.000 claims description 8
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 4
- 239000000460 chlorine Substances 0.000 claims description 3
- 229910052731 fluorine Inorganic materials 0.000 claims description 3
- 239000011737 fluorine Substances 0.000 claims description 3
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 claims description 3
- 229910000041 hydrogen chloride Inorganic materials 0.000 claims description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 2
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 claims description 2
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims description 2
- 229910052801 chlorine Inorganic materials 0.000 claims description 2
- 229910000037 hydrogen sulfide Inorganic materials 0.000 claims description 2
- 238000012805 post-processing Methods 0.000 claims description 2
- 230000035484 reaction time Effects 0.000 claims description 2
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 claims 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract description 10
- 229910052698 phosphorus Inorganic materials 0.000 abstract description 9
- 229910052742 iron Inorganic materials 0.000 abstract description 7
- 238000011084 recovery Methods 0.000 abstract description 6
- 239000003153 chemical reaction reagent Substances 0.000 abstract description 5
- 239000012535 impurity Substances 0.000 abstract description 5
- 230000000052 comparative effect Effects 0.000 description 41
- 239000000047 product Substances 0.000 description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 12
- 239000011268 mixed slurry Substances 0.000 description 10
- 239000000843 powder Substances 0.000 description 10
- 239000008367 deionised water Substances 0.000 description 8
- 229910021641 deionized water Inorganic materials 0.000 description 8
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 description 7
- 238000001027 hydrothermal synthesis Methods 0.000 description 6
- 239000002245 particle Substances 0.000 description 6
- 229910010707 LiFePO 4 Inorganic materials 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 229910000398 iron phosphate Inorganic materials 0.000 description 5
- 238000005406 washing Methods 0.000 description 5
- 229910010710 LiFePO Inorganic materials 0.000 description 4
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-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
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 239000011230 binding agent Substances 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- 238000001914 filtration Methods 0.000 description 4
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 4
- 229910052808 lithium carbonate Inorganic materials 0.000 description 4
- 229910003002 lithium salt Inorganic materials 0.000 description 4
- 159000000002 lithium salts Chemical class 0.000 description 4
- 239000007800 oxidant agent Substances 0.000 description 4
- 238000001556 precipitation Methods 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 229910001882 dioxygen Inorganic materials 0.000 description 3
- 239000003792 electrolyte Substances 0.000 description 3
- 238000000605 extraction Methods 0.000 description 3
- 238000010335 hydrothermal treatment Methods 0.000 description 3
- -1 hydroxide ions Chemical class 0.000 description 3
- 238000009616 inductively coupled plasma Methods 0.000 description 3
- 239000007791 liquid phase Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 3
- 238000006479 redox reaction Methods 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 230000000087 stabilizing effect Effects 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 239000005955 Ferric phosphate Substances 0.000 description 2
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000029087 digestion Effects 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 229940032958 ferric phosphate Drugs 0.000 description 2
- 235000019253 formic acid Nutrition 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 229910000399 iron(III) phosphate Inorganic materials 0.000 description 2
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- 150000005838 radical anions Chemical class 0.000 description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 description 2
- 239000010926 waste battery Substances 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- JQMFQLVAJGZSQS-UHFFFAOYSA-N 2-[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]piperazin-1-yl]-N-(2-oxo-3H-1,3-benzoxazol-6-yl)acetamide Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)N1CCN(CC1)CC(=O)NC1=CC2=C(NC(O2)=O)C=C1 JQMFQLVAJGZSQS-UHFFFAOYSA-N 0.000 description 1
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 1
- 229910018091 Li 2 S Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- QZPSXPBJTPJTSZ-UHFFFAOYSA-N aqua regia Chemical compound Cl.O[N+]([O-])=O QZPSXPBJTPJTSZ-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000004993 emission spectroscopy Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 238000009854 hydrometallurgy Methods 0.000 description 1
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 description 1
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 description 1
- 229910000360 iron(III) sulfate Inorganic materials 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 125000000896 monocarboxylic acid group Chemical group 0.000 description 1
- 239000010450 olivine Substances 0.000 description 1
- 229910052609 olivine Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- DHCDFWKWKRSZHF-UHFFFAOYSA-L thiosulfate(2-) Chemical compound [O-]S([S-])(=O)=O DHCDFWKWKRSZHF-UHFFFAOYSA-L 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B26/00—Obtaining alkali, alkaline earth metals or magnesium
- C22B26/10—Obtaining alkali metals
- C22B26/12—Obtaining lithium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
- C22B7/006—Wet processes
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
The invention discloses a method for recycling lithium from lithium iron phosphate waste, and relates to the technical field of batteries. A method for recovering lithium from lithium iron phosphate waste material, comprising the steps of: the slurry containing lithium iron phosphate waste reacts under the conditions that the partial pressure of oxidizing gas is more than or equal to 0.2MPa, the partial pressure of acid gas is more than or equal to 0.4MPa and the reaction temperature is 90-150 ℃, and solid-liquid separation is carried out, so as to obtain lithium-containing aqueous solution. The method can efficiently recover lithium from the lithium iron phosphate waste, does not need to add chemical reagents in the leaching process, has high lithium recovery rate, almost does not leach out impurities such as Fe, P and the like, and has short time consumption.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to a method for recycling lithium from lithium iron phosphate waste.
Background
Lithium iron phosphate (LiFePO) 4 ) The method has the advantages of higher theoretical capacity, energy density, working voltage, excellent thermal safety and the like, and is widely applied to the fields of electric automobiles and energy storage. In order to lighten the environmental pressure generated by the waste batteries and fully utilize lithium-containing resources, it is important to recycle the waste batteries. However, since lithium iron phosphate is low-value-added material, except lithium, the remaining components are low-value-added materials. Thus, low cost LiFePO was developed 4 The cathode material has great significance in high efficiency and green lithium extraction technology.
Hydrometallurgy is currently processing LiFePO 4 The main method of the material can be summarized into four steps of leaching, impurity removal, separation and product preparation. Wherein the co-leaching from LiFePO can be achieved by an acid/oxidant co-leaching 4 And the selective extraction of lithium, thereby saving the consumption of acid/alkali reagents. The oxidizing agents reported so far mainly comprise hydrogen peroxide (H 2 O 2 ) Thiosulfate (Na/K/NH) 4 -S 2 O 8 ) Ferric sulfate (Fe) 2 (SO 4 ) 3 ) Etc.; the acid mainly comprises sulfuric acid (H) 2 SO 4 ) Formic acid (HCOOH), acetic acid (CH) 3 COOH) and the like. By H 2 SO 4 /H 2 O 2 For example, although selective leaching reduces the consumption of acid to some extent, excessive acid and oxidant are still needed to ensure certain leaching kinetics under homogeneous reaction, H 2 SO 4 The consumption is generally 3 to 5 times of the theoretical consumption, H 2 O 2 The consumption is generally 7 to 10 times the theoretical consumption. Unreacted acid or oxidant, etc., eventually enters the wastewater to form high salt wastewater, and the cost of the recovery process is increased.
Therefore, it is very important to provide a green extraction method that has low cost, high leaching rate and short time for recovering lithium from lithium iron phosphate waste.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the method for recycling lithium from the lithium iron phosphate waste material provided by the invention has the advantages that no synthetic chemical reagent is required to be introduced, the lithium can be efficiently recycled from the lithium iron phosphate waste material, the time consumption is short, and the recycling rate is high.
According to an embodiment of the first aspect of the present invention, a method for recovering lithium from lithium iron phosphate waste material comprises the steps of:
the slurry containing lithium iron phosphate waste reacts under the conditions that the partial pressure of oxidizing gas is more than or equal to 0.2MPa, the partial pressure of acid gas is more than or equal to 0.4MPa and the reaction temperature is 90-150 ℃, and solid-liquid separation is carried out, so as to obtain lithium-containing aqueous solution.
The method according to the embodiment of the invention has at least the following beneficial effects:
oxidative-The solubility of the acid gas in the solution is very low, and the oxidizing/acid gas is introduced into the slurry by a bubbling method, liFePO 4 The contact time of the particles and the oxidizing/acid gas is short, and the chemical reaction rate is low; in addition, oxidizing/acid gases and LiFePO 4 The chemical reaction between particles involves a gas-liquid-solid three-phase reaction interface, and the dynamics are slow; liFePO 4 The surface layer of the particles can react with oxidizing gas, and FePO can be formed on the surface of the particles after selective lithium removal 4 Shell layer, block LiFePO 4 Contact with oxidizing gas to cause LiFePO 4 The interior of the particles is difficult to contact and react with the gas, resulting in low leaching efficiency of lithium.
The invention can improve the solubility of the oxidizing/acid gas in water, improve the oxidation potential of the solution, improve the rate of oxidation-reduction reaction and effectively solve the problems of gas and LiFePO by adopting a pressurizing mode 4 A problem of contact between particles; by introducing acid gas (applying pressure) into the system, weak acid condition can be created for the system, thereby reducing Al and FePO 4 And the dissolution of the like, the continuous progress of the oxidation-reduction reaction is ensured, the recovery efficiency of Li is improved, and impurities such as Fe, P and the like are hardly leached out. When the acid gas is CO 2 When the method is used, any synthetic chemical reagent is not required to be introduced, impurity anions are not required to be introduced, the lithium carbonate product is directly obtained, and the purity of the recovered product is not influenced.
The specific reaction process is as follows: the oxidizing gas and the acid gas are simultaneously introduced into the solution, the oxidizing gas dissolved in the liquid phase is in contact reaction with the lithium iron phosphate powder, and the ferrous iron in the lithium iron phosphate is oxidized into trivalent iron. To maintain charge balance, lithium migrates from the lattice into solution. The oxidizing gas generates hydroxide ions when reduced, resulting in an increase in the pH of the solution, which is detrimental to the continued progress of the redox reaction. The acidic gas is dissolved to ionize hydrogen ions and neutralize hydroxide ions, thereby promoting continuous precipitation of lithium. The obtained leaching solution contains lithium ions and acid radical anions. After the lithium is extracted from the olivine lattice, the iron and phosphorus exist in the form of iron phosphate. And (3) separating iron phosphate filter residues through solid-liquid separation to obtain a liquid phase mainly containing lithium ions and acid radical anions, so as to form soluble lithium salt. The final lithium salt product can be obtained after direct heating, evaporation and drying.
The method of the embodiment has no requirement on the pH of the slurry, the pH of the slurry is not required to be further regulated by adding acid or alkali, and only the lithium iron phosphate powder is required to be added into water.
According to some embodiments of the invention, the source of lithium iron phosphate waste material comprises at least one of battery factory tailings and retired power battery recycle.
According to some embodiments of the invention, the lithium iron phosphate waste material comprises at least one of a binder, carbon, aluminum in addition to the lithium iron phosphate.
According to some embodiments of the invention, the method further comprises a pre-reaction treatment. The pretreatment of the reaction comprises: washing lithium iron phosphate waste with an organic solvent N-methylpyrrolidone (NMP) at 60 ℃ for 2 hours; the repetition times are 2 to 4 times. Thus, impurities such as a binder (e.g., PVDF), residual lithium salt, and an electrolyte (e.g., a fluorine-containing electrolyte) can be removed. After washing with the organic solvent, washing with water is continued for 1-2 times.
According to some embodiments of the invention, the oxidizing gas comprises oxygen (O 2 ) Ozone (O) 3 ) Chlorine (Cl) 2 ) Fluorine gas (F) 2 ) At least one of them. For example: specifically, O may be 2 。
According to some embodiments of the invention, the acid gas comprises carbon dioxide (CO 2 ) Hydrogen sulfide (H) 2 S), hydrogen chloride (HCl), sulfur dioxide (SO) 2 ) At least one of them. For example: in particular CO 2 。
According to some embodiments of the invention, the liquid phase of the slurry is water.
According to some embodiments of the invention, the slurry has a solids to liquid ratio of 1g:5 mL-100 mL. Further 1g:20 mL-90 mL. For example: specifically, 1g:20mL, 1g:5mL or 1g:90mL. If the solid-to-liquid ratio is too large, the stirring of the slurry and the contact of gas and lithium iron phosphate waste are affected; if the solid-to-liquid ratio is too low, the lithium concentration in the filtrate and the subsequent precipitation efficiency are affected.
According to some embodiments of the invention, the partial pressure of the oxidizing gas is between 0.2MPa and 2MPa. Further 0.2MPa to 1.5MPa. Further, the pressure may be 0.4MPa to 1MPa. Still further, the pressure may be 0.4MPa to 0.6MPa.
According to some embodiments of the invention, the acid gas partial pressure is between 0.4MPa and 2MPa. Further 0.4MPa to 1.5MPa. Further, the pressure may be 0.4MPa to 1.2MPa. Still further, the pressure may be 0.4MPa to 1MPa.
According to some embodiments of the invention, the reaction temperature is 90 ℃ to 120 ℃. Further, the temperature may be 90℃to 100 ℃.
According to some embodiments of the invention, the reaction time is 1h to 10h. Further, the time may be 1 to 8 hours. Still further, the time may be 1 to 6 hours. Still further, the time may be 1.5 to 2.5 hours.
According to some embodiments of the invention, the pH of the lithium-containing aqueous solution after the reaction is between 8.0 and 10. After hydrothermal reaction, the pH of the aqueous solution containing lithium at normal temperature and normal pressure is alkalescent, and the rising degree of the pH is positively correlated with the leaching rate of lithium iron phosphate. The method can ensure that a small amount of metal aluminum powder remained in the lithium iron phosphate waste is not dissolved without further manual adjustment of the pH value of the lithium-containing aqueous solution, and the purity of the final Li-containing product is not affected.
According to some embodiments of the invention, the method further comprises post-treating the aqueous lithium-containing solution. The post-processing includes: and carrying out heat treatment on the lithium-containing aqueous solution or mixing the lithium-containing aqueous solution with carbonate to obtain a lithium-containing product. Post-treatment of the lithium-containing product may also be included. The post-treatment comprises filtration, washing and drying.
With the acid gas as CO 2 For example, the specific reaction mechanism is as follows:
when the acid gases are H respectively 2 S, HCl or SO 2 When the soluble lithium salts in the lithium-containing aqueous solution are respectively Li 2 S、LiCl、Li 2 SO 4 The subsequent lithium precipitation treatment common in the field, such as adding sodium carbonate, can separate and obtain high-purity Li 2 CO 3 。
According to some embodiments of the invention, the temperature of the heat treatment is 80 ℃ to 180 ℃. Further, the temperature may be 80℃to 120 ℃. And further may be 90℃to 110 ℃.
According to some embodiments of the invention, the heat treatment may be a stirred heat treatment. The stirring speed is 400 r/min-1000 r/min. Further, the ratio may be 400 to 800r/min. Further, the ratio may be 500 to 700r/min.
According to some embodiments of the invention, the heat treatment is for a time period of 0.5h to 4h. Further, the time may be 1 to 3 hours. For example: may be 2h.
According to some embodiments of the invention, the lithium leaching rate of the method is equal to or greater than 75%. Can be more than or equal to 90 percent. Further can be more than or equal to 95 percent. Further, the content of the active components is more than or equal to 98 percent. Still more, the content of the active components is more than or equal to 99 percent.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Detailed Description
The conception and the technical effects produced by the present invention will be clearly and completely described in conjunction with the embodiments below to fully understand the objects, features and effects of the present invention. It is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments, and that other embodiments obtained by those skilled in the art without inventive effort are within the scope of the present invention based on the embodiments of the present invention.
The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
In the description of the present invention, the terms "comprises" and "comprising," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Unless otherwise indicated, the term "normal temperature" in the present invention means 25.+ -. 2 ℃.
The lithium iron phosphate powder used in the following examples (84.4 wt% of lithium iron phosphate, 0.7wt% of binder PVDF, 14.25wt% of carbon, 0.65wt% of aluminum) was treated by the following pretreatment method:
100g of lithium iron phosphate waste (composed of 70wt% of lithium iron phosphate, 4.5wt% of PVDF4.5wt% of binder, 6wt% of electrolyte, 2wt% of metal copper scraps and 2wt% of aluminum scraps) was mixed with 100mL of NMP (N-methylpyrrolidone), stirred at 60℃for 2 hours, and filtered; repeatedly treating the filter residue for 2 times under the above conditions to obtain solid; and then washing the obtained solid with 100mL of deionized water for 1 time at normal temperature, and drying the obtained solid to obtain the lithium iron phosphate powder.
Example 1
The embodiment provides a method for recovering lithium from lithium iron phosphate waste, which comprises the following steps:
10g of lithium iron phosphate powder was mixed with 200mL of deionized water to prepare a mixed slurry (pH 6.9); the mixed slurry was placed in a pressurized reaction kettle and stirred at a constant rate (600 r/min). Sealing the reaction system, raising the temperature to 120 ℃, and respectively introducing O after the pressure gauge is stable 2 And CO 2 . First let in O 2 Controlling the partial pressure of oxygen to be 0.4MPa; after the partial pressure of oxygen is stable, introducing CO into the system 2 The partial pressure of carbon dioxide was controlled to 0.4MPa. Continuously stabilizing O during the reaction 2 And CO 2 And (3) after the pressure and hydrothermal treatment for 2 hours, filtering to obtain a lithium-containing aqueous solution and ferric phosphate solid respectively.
Example 2
This example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 1, except that: the temperature was replaced by 150℃from 120 ℃.
Example 3
10g of lithium iron phosphate powder was mixed with 200mL of deionized water to prepare a mixed slurry (pH 6.9); the mixed slurry was placed in a pressurized reaction kettle and stirred at a constant rate (600 r/min). Sealing the reaction system, raising the temperature to 90 ℃, and respectively introducing O after the pressure gauge is stable 2 And CO 2 . First let in O 2 Controlling the partial pressure of oxygen to be 0.2MPa; after the partial pressure of oxygen is stable, introducing CO into the system 2 The partial pressure of carbon dioxide was controlled to 0.4MPa. Continuously stabilizing O during the reaction 2 And CO 2 And (3) after the pressure and hydrothermal treatment for 2 hours, filtering to obtain a lithium-containing aqueous solution and ferric phosphate solid respectively.
Example 4
This example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 3, except that: the partial pressure of oxygen was replaced by 1MPa from 0.2MPa.
Example 5
The embodiment provides a method for recovering lithium from lithium iron phosphate waste, which comprises the following steps:
s1, mixing 10g of lithium iron phosphate powder with 200mL of deionized water to prepare mixed slurry (pH is 6.9); placing the mixed slurry into a pressurized reaction kettle, sealing the reaction system, heating to 90 ℃, and respectively introducing O after a pressure gauge is stable 2 And CO 2 . First let in O 2 Controlling the partial pressure of oxygen to be 0.4MPa; after the partial pressure of oxygen is stable, introducing CO into the system 2 The partial pressure of carbon dioxide was controlled to 1MPa. Continuously stabilizing O during the reaction 2 And CO 2 After 2h of pressure and hydrothermal treatment, filtration gave lithium-containing aqueous solution (pH 9.94) and iron phosphate solids, respectively.
S2, heating and evaporating the lithium-containing aqueous solution at the temperature of 100 ℃ and stirring at the speed of 600r/min to obtain a crystal product. The obtained crystal product is washed by deionized water, filtered by vacuum suction, dried in a blast drying oven at 80 ℃ to obtain the final lithium carbonate (Li) 2 CO 3 ) And (5) a product.
Example 6
This example provides a method for recovering lithium from lithium iron phosphate waste material, substantially the same as in example 5The only differences are: by oxidizing gas species from O 2 Replaced by O 3 。
Example 7
This example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 5, except that: acid gas species from CO 2 Replacement by SO 2 。
Example 8
This example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 5, except that: acid gas species from CO 2 Replaced by H 2 S。
Example 9
This example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 5, except that: the time of the hydrothermal reaction was replaced by 1.0h from 2h.
Example 10
This example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 5, except that: the time of the hydrothermal reaction was replaced by 1.5h from 2h.
Example 11
This example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 5, except that: the time of the hydrothermal reaction was replaced by 2.5h.
Example 12
This example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 5, except that: the solid-to-liquid ratio was set at 1g:20mL was increased to 1g:5mL.
Example 13
This example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 5, except that: the solid-to-liquid ratio was set at 1g:20mL was reduced to 1g:90mL.
Comparative example 1
This comparative example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 1, except that: the temperature was replaced by 30℃from 120 ℃.
Comparative example 2
This comparative example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 1, except that: the temperature was replaced by 60℃from 120 ℃.
Comparative example 3
This comparative example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 1, except that: the temperature was replaced by 180℃from 120 ℃.
Comparative example 4
This comparative example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 1, except that: the temperature was replaced by 210℃from 120 ℃.
Comparative example 5
This comparative example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 5, except that: the partial pressure of carbon dioxide was replaced by 0.0MPa from 1MPa.
Comparative example 6
This comparative example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 5, except that: the partial pressure of carbon dioxide was replaced by 0.2MPa from 1MPa.
Comparative example 7
This comparative example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to example 5, except that: the time of the hydrothermal reaction was replaced by 0.5h from 2h.
Comparative example 8
This comparative example provides a method for recovering lithium from lithium iron phosphate waste material, comprising the steps of:
10g of lithium iron phosphate powder was mixed with 200mL of deionized water to prepare a mixed slurry (pH 6.9); introducing O into the mixed slurry 2 (gas flow rate was 0.5L/min), stirred at a constant rate (600 r/min), reacted at 25℃for 12 hours, and filtered to obtain an aqueous lithium-containing solution and an iron phosphate solid, respectively.
Comparative example 9
This comparative example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to comparative example 8, except that: the oxygen gas flow was replaced by 0.75L/min from 0.5L/min.
Comparative example 10
This comparative example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to comparative example 8, except that: the oxygen gas flow was replaced with 1.0L/min from 0.5L/min.
Comparative example 11
This comparative example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to comparative example 8, except that: the oxygen gas flow was replaced with 1.5L/min from 0.5L/min.
Comparative example 12
This comparative example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to comparative example 8, except that: the reaction temperature was replaced by 90℃from 25 ℃.
Comparative example 13
This comparative example provides a method for recovering lithium from lithium iron phosphate waste material, comprising the steps of:
mixing 10g of lithium iron phosphate powder with 200mL of deionized water to prepare mixed slurry; simultaneously introducing O into the mixed slurry 2 (gas flow rate of 0.75L/min) and CO 2 (gas flow rate was 0.8L/min), stirred at a constant rate (600 r/min), reacted at 25℃for 12 hours, and filtered to obtain an aqueous lithium-containing solution and an iron phosphate solid, respectively.
Comparative example 14
This comparative example provides a method for recovering lithium from lithium iron phosphate waste material, substantially identical to comparative example 13, except that: the reaction temperature was replaced by 90℃from 25 ℃.
Detection example 1
This test example was conducted to examine the leaching rates of Li, fe and P elements in the lithium-containing aqueous solutions of examples 1 to 13 and comparative examples 1 to 14. The detection method comprises the following steps:
and after the lithium-containing aqueous solution is subjected to ICP test, the concentration of Li, fe and P elements is obtained. And calculating the leaching rate of each element according to the content of Li, fe and P elements in the raw materials. The leaching rate calculation formula is specifically as follows:
the test results are shown in Table 1.
TABLE 1
As is clear from examples 1 to 2 and comparative examples 1 to 4, the leaching rate of Li gradually increased with an increase in temperature within a certain range. When the temperature is raised to more than 150 ℃, part of P element is leached out. This may be due to LiFePO 4 The instability of the structure at high temperatures results in a lower purity of the recovered lithium carbonate product.
As is clear from comparative examples 3 to 4, the leaching rate of Li gradually increases with an increase in the partial pressure of oxygen, while the leaching rates of Fe and P are not affected. However, it can be seen from the data that the effect of the partial pressure of oxygen on the Li leaching rate is not particularly pronounced.
As is clear from examples 5 and comparative examples 5 to 6, the leaching rate of Li gradually increases with an increase in the partial pressure of carbon dioxide, while the leaching rates of Fe and P are not affected.
As is clear from examples 5 to 8, different types of oxidizing gases (O 3 ) And acid gas (H) 2 S、SO 2 ) Can obtain higher leaching rate without affecting the leaching of Li.
As is evident from examples 5, 9 to 11 and comparative example 7, the leaching rate of Li gradually increases as the time of the hydrothermal reaction increases, while the leaching rates of Fe and P are not affected.
As is clear from comparative examples 8 to 11, O was directly introduced 2 The recovery of lithium in the lithium iron phosphate waste is performed in the form of (1) and a good Li recovery effect cannot be obtained, and the change of the gas flow rate does not significantly affect the Li leaching rate. Even if the reaction temperature is increasedIt is also difficult to significantly enhance the Li leaching rate up to 90 ℃ (comparative example 12).
As is clear from comparative examples 13 to 14, O was introduced directly 2 And CO 2 The form of (2) is used for recovering lithium in lithium iron phosphate waste, the good Li recovery effect can not be obtained under the conditions of 25 ℃ and 90 ℃,
detection example 2
This test example is conducted on Li prepared in example 5 2 CO 3 The purity of the product is detected by the following method:
weigh 50mg Li 2 CO 3 The product was added to 20mL aqua regia (concentrated HCl: concentrated HNO) 3 =3:1), digesting for 3 hours at 130 ℃, observing the solid-free powder, and adding deionized water to fix the volume to 100mL to obtain a digestion solution. The content of each element in the digestion solution was tested by inductively coupled plasma emission spectrometry (ICP-OES).
The test results are shown in Table 2.
TABLE 2
| Element(s) | Li | Fe | P | Al | Cu |
| Concentration/mg L -1 | 93.42 | 1.35 | 0.4 | 0.05 | 0.95 |
| Mass fraction/% | 18.68 | 0.27 | 0.08 | 0.01 | 0.19 |
Failure to detect Li due to ICP 2 CO 3 C, O element content in the product, li 2 CO 3 The product purity was determined from the measured mass fraction of Li. Li (Li) 2 CO 3 The theoretical mass fraction of Li in the alloy is 18.79%, and Li is calculated 2 CO 3 The product purity was 99.41% (18.68%/18.79% ×100% = 99.41%).
Lithium iron phosphate waste materials were recovered by the methods of examples 1 to 16 to obtain lithium-containing aqueous solutions, and further heat treatment or precipitation of lithium by adding sodium carbonate, high-purity lithium carbonate having a purity of >99.25% was obtained.
The embodiments of the present invention have been described in detail with reference to the embodiments, but the present invention is not limited to the embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present invention.
Claims (10)
1. A method for recovering lithium from lithium iron phosphate waste material, comprising the steps of:
the slurry containing lithium iron phosphate waste reacts under the conditions that the partial pressure of oxidizing gas is more than or equal to 0.2MPa, the partial pressure of acid gas is more than or equal to 0.4MPa and the reaction temperature is 90-150 ℃, and solid-liquid separation is carried out, so as to obtain lithium-containing aqueous solution.
2. The method of claim 1, wherein the oxidizing gas comprises at least one of oxygen, ozone, chlorine, fluorine.
3. The method of claim 1, wherein the acid gas comprises at least one of carbon dioxide, hydrogen sulfide, hydrogen chloride, and sulfur dioxide.
4. The method of claim 1, wherein the reaction temperature is from 90 ℃ to 120 ℃.
5. The method of claim 1, wherein the partial pressure of the oxidizing gas is between 0.2MPa and 2MPa.
6. The method of claim 1, wherein the slurry has a solids to liquid ratio of 1g:5 mL-100 mL.
7. The method according to claim 1, wherein the reaction time is 1 to 10 hours; preferably 1.5 to 8 hours.
8. The method of claim 1, further comprising post-treating the aqueous lithium-containing solution; the post-processing includes: and carrying out heat treatment on the lithium-containing aqueous solution or mixing the lithium-containing aqueous solution with carbonate to obtain a lithium-containing product.
9. The method of claim 1, wherein the acid gas partial pressure is between 0.4MPa and 2MPa.
10. The method of claim 1, wherein the lithium leaching rate of the method is greater than or equal to 75%.
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