CN115818601A - Titanium-doped battery-grade iron phosphate and preparation method thereof - Google Patents
Titanium-doped battery-grade iron phosphate and preparation method thereof Download PDFInfo
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- CN115818601A CN115818601A CN202211557232.8A CN202211557232A CN115818601A CN 115818601 A CN115818601 A CN 115818601A CN 202211557232 A CN202211557232 A CN 202211557232A CN 115818601 A CN115818601 A CN 115818601A
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- titanium
- iron
- ferrous sulfate
- phosphate
- iron phosphate
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- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 title claims abstract description 74
- 229910000398 iron phosphate Inorganic materials 0.000 title claims abstract description 66
- 238000002360 preparation method Methods 0.000 title claims abstract description 16
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 116
- 239000010936 titanium Substances 0.000 claims abstract description 104
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims abstract description 86
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 82
- 235000003891 ferrous sulphate Nutrition 0.000 claims abstract description 69
- 239000011790 ferrous sulphate Substances 0.000 claims abstract description 69
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims abstract description 69
- 229910000359 iron(II) sulfate Inorganic materials 0.000 claims abstract description 69
- 238000000034 method Methods 0.000 claims abstract description 48
- 229910052742 iron Inorganic materials 0.000 claims abstract description 39
- 238000006243 chemical reaction Methods 0.000 claims abstract description 37
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 33
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 18
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000001301 oxygen Substances 0.000 claims abstract description 18
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 18
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 17
- 229910019142 PO4 Inorganic materials 0.000 claims abstract description 16
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims abstract description 16
- 239000010452 phosphate Substances 0.000 claims abstract description 16
- IXQWNVPHFNLUGD-UHFFFAOYSA-N iron titanium Chemical compound [Ti].[Fe] IXQWNVPHFNLUGD-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000006227 byproduct Substances 0.000 claims abstract description 14
- 238000000926 separation method Methods 0.000 claims abstract description 14
- 239000003054 catalyst Substances 0.000 claims abstract description 13
- 230000003197 catalytic effect Effects 0.000 claims abstract description 13
- 239000007789 gas Substances 0.000 claims abstract description 13
- 238000004519 manufacturing process Methods 0.000 claims abstract description 13
- 239000007787 solid Substances 0.000 claims abstract description 13
- 239000004408 titanium dioxide Substances 0.000 claims abstract description 13
- 238000001035 drying Methods 0.000 claims abstract description 10
- 239000007788 liquid Substances 0.000 claims abstract description 10
- 238000005406 washing Methods 0.000 claims abstract description 6
- 229910000403 monosodium phosphate Inorganic materials 0.000 claims description 7
- 235000019799 monosodium phosphate Nutrition 0.000 claims description 7
- AJPJDKMHJJGVTQ-UHFFFAOYSA-M sodium dihydrogen phosphate Chemical compound [Na+].OP(O)([O-])=O AJPJDKMHJJGVTQ-UHFFFAOYSA-M 0.000 claims description 7
- LPXPTNMVRIOKMN-UHFFFAOYSA-M sodium nitrite Chemical group [Na+].[O-]N=O LPXPTNMVRIOKMN-UHFFFAOYSA-M 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 3
- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 claims description 3
- 229910000387 ammonium dihydrogen phosphate Inorganic materials 0.000 claims description 3
- 239000001257 hydrogen Substances 0.000 claims description 3
- 229910052739 hydrogen Inorganic materials 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- 235000019837 monoammonium phosphate Nutrition 0.000 claims description 3
- 239000002893 slag Substances 0.000 claims description 3
- 235000010288 sodium nitrite Nutrition 0.000 claims description 3
- 229910052698 phosphorus Inorganic materials 0.000 claims description 2
- 239000011574 phosphorus Substances 0.000 claims description 2
- 239000000243 solution Substances 0.000 abstract description 89
- 239000012535 impurity Substances 0.000 abstract description 17
- 235000010215 titanium dioxide Nutrition 0.000 abstract description 16
- 239000000463 material Substances 0.000 abstract description 11
- 239000000047 product Substances 0.000 abstract description 11
- 239000002994 raw material Substances 0.000 abstract description 11
- 239000002253 acid Substances 0.000 abstract description 9
- 239000011259 mixed solution Substances 0.000 abstract description 5
- 230000008569 process Effects 0.000 description 17
- 230000000052 comparative effect Effects 0.000 description 15
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 15
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 11
- 239000000126 substance Substances 0.000 description 11
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 10
- 229910001448 ferrous ion Inorganic materials 0.000 description 10
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 8
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 239000005955 Ferric phosphate Substances 0.000 description 7
- 229940032958 ferric phosphate Drugs 0.000 description 7
- 229910000399 iron(III) phosphate Inorganic materials 0.000 description 7
- 230000003647 oxidation Effects 0.000 description 7
- 238000000746 purification Methods 0.000 description 7
- 229910010413 TiO 2 Inorganic materials 0.000 description 6
- 238000001914 filtration Methods 0.000 description 6
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 6
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 5
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 5
- 229910001416 lithium ion Inorganic materials 0.000 description 5
- 229910010710 LiFePO Inorganic materials 0.000 description 4
- 229910010707 LiFePO 4 Inorganic materials 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 4
- WDIHJSXYQDMJHN-UHFFFAOYSA-L barium chloride Chemical compound [Cl-].[Cl-].[Ba+2] WDIHJSXYQDMJHN-UHFFFAOYSA-L 0.000 description 4
- 229910001626 barium chloride Inorganic materials 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- YDZQQRWRVYGNER-UHFFFAOYSA-N iron;titanium;trihydrate Chemical compound O.O.O.[Ti].[Fe] YDZQQRWRVYGNER-UHFFFAOYSA-N 0.000 description 4
- 229910052744 lithium Inorganic materials 0.000 description 4
- 238000001000 micrograph Methods 0.000 description 4
- 239000012071 phase Substances 0.000 description 4
- 239000002244 precipitate Substances 0.000 description 4
- 238000011084 recovery Methods 0.000 description 4
- 238000006722 reduction reaction Methods 0.000 description 4
- 238000001878 scanning electron micrograph Methods 0.000 description 4
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 4
- 239000000725 suspension Substances 0.000 description 4
- 238000005303 weighing Methods 0.000 description 4
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 3
- 238000000498 ball milling Methods 0.000 description 3
- 230000005587 bubbling Effects 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 239000000706 filtrate Substances 0.000 description 3
- 229910021645 metal ion Inorganic materials 0.000 description 3
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- 230000009467 reduction Effects 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 description 3
- JUWGUJSXVOBPHP-UHFFFAOYSA-B titanium(4+);tetraphosphate Chemical compound [Ti+4].[Ti+4].[Ti+4].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O JUWGUJSXVOBPHP-UHFFFAOYSA-B 0.000 description 3
- BZSXEZOLBIJVQK-UHFFFAOYSA-N 2-methylsulfonylbenzoic acid Chemical compound CS(=O)(=O)C1=CC=CC=C1C(O)=O BZSXEZOLBIJVQK-UHFFFAOYSA-N 0.000 description 2
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 239000010405 anode material Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000005660 chlorination reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910001447 ferric ion Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 2
- 229910052808 lithium carbonate Inorganic materials 0.000 description 2
- 238000013508 migration Methods 0.000 description 2
- 230000005012 migration Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000004321 preservation Methods 0.000 description 2
- 238000010992 reflux Methods 0.000 description 2
- 239000012266 salt solution Substances 0.000 description 2
- 235000010344 sodium nitrate Nutrition 0.000 description 2
- 239000004317 sodium nitrate Substances 0.000 description 2
- 239000007790 solid phase Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- 229910012465 LiTi Inorganic materials 0.000 description 1
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- -1 barium-activated lithium iron phosphate Chemical class 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000013065 commercial product Substances 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
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- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
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- SZVJSHCCFOBDDC-UHFFFAOYSA-N ferrosoferric oxide Chemical compound O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- 229960002089 ferrous chloride Drugs 0.000 description 1
- 229940062993 ferrous oxalate Drugs 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000008103 glucose Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 238000001027 hydrothermal synthesis Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 1
- OWZIYWAUNZMLRT-UHFFFAOYSA-L iron(2+);oxalate Chemical compound [Fe+2].[O-]C(=O)C([O-])=O OWZIYWAUNZMLRT-UHFFFAOYSA-L 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 231100000956 nontoxicity Toxicity 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 239000010450 olivine Substances 0.000 description 1
- 229910052609 olivine Inorganic materials 0.000 description 1
- SOQBVABWOPYFQZ-UHFFFAOYSA-N oxygen(2-);titanium(4+) Chemical compound [O-2].[O-2].[Ti+4] SOQBVABWOPYFQZ-UHFFFAOYSA-N 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- DPTATFGPDCLUTF-UHFFFAOYSA-N phosphanylidyneiron Chemical compound [Fe]#P DPTATFGPDCLUTF-UHFFFAOYSA-N 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
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- 239000011734 sodium Substances 0.000 description 1
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- 238000006467 substitution reaction Methods 0.000 description 1
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- 229910000349 titanium oxysulfate Inorganic materials 0.000 description 1
- 238000001291 vacuum drying Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Images
Classifications
-
- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Compounds Of Iron (AREA)
Abstract
The invention relates to the technical field of battery materials, in particular to titanium-doped battery-grade iron phosphate and a preparation method thereof. The preparation method of the titanium-doped battery-grade iron phosphate comprises the following steps: adding iron-containing titanium ore into a ferrous sulfate solution to obtain a first mixed system; then adding the mixed solution and a phosphate solution into a reaction container in a shunting manner to obtain a second mixed system, adding a catalyst, introducing oxygen-containing gas to perform catalytic oxidation reaction to obtain a third mixed system, performing solid-liquid separation, collecting solid matters, washing and drying; ferrous sulfate is a byproduct in the production process of titanium dioxide by a sulfuric acid method; the ferrous sulfate solution also contains titanium element; the adding time of the iron-titanium containing ore is 4-8 min. The method takes the ferrous sulfate byproduct produced in the production process of titanium white by a sulfuric acid method as a raw material, removes impurities in the preparation process of the iron phosphate through the operation, retains a small amount of titanium and the iron phosphate to be uniformly co-precipitated, realizes the doping of the ortho-acid, and obtains a uniform and stable product.
Description
Technical Field
The invention relates to the technical field of battery materials, in particular to titanium-doped battery-grade iron phosphate and a preparation method thereof.
Background
Olivine structured LiFePO was discovered in 1997 by Goodenough et al 4 Li at a potential value of 3.4V (vs. Li) + Li), the lithium ion can be reversibly inserted and removed, and the lithium ion battery becomes a widely used anode material of the current lithium battery due to the advantages of low synthesis cost, no toxicity, good safety and stability and the like.
The technical route for industrially producing lithium iron phosphate includes an iron oxide red route, a ferrous oxalate route, a hydrothermal synthesis route and an iron orthophosphate route according to different raw materials. Through practice and verification of the industry and the market, the lithium iron phosphate prepared by the ferric phosphate route has the outstanding advantages of good electrical property, low impurity content, simple process steps and the like, and gradually becomes a technical trend of industry unification.
Due to LiFePO 4 LiFePO is used in the charge and discharge process of the material 4 And FePO 4 In order to obtain a final two-phase structure (the crystal structures of the two are basically consistent, and the unit cell parameters are not greatly changed), ferric phosphate is used as a basic raw material to prepare LiFePO 4 Ferric phosphate FePO 4 The composition, structure and morphology characteristics of the polymer will directly affect the properties of the final product.
The pure-phase lithium iron phosphate has low electronic conductivity, so that the charge-discharge efficiency and the discharge specific capacity of the pure-phase lithium iron phosphate are low, particularly the rate capability is poor, and the wide application of the pure-phase lithium iron phosphate is greatly limited. At present, the electrochemical performance of lithium iron phosphate is mainly improved through surface carbon coating and ion doping.
The surface carbon coating can improve the electronic conductivity of the material, promote the migration of lithium ions, improve the charge-discharge efficiency and improve the rate discharge performance; the crystal structure of the lithium iron phosphate can be changed by ion doping, so that crystal lattices are distorted, a lithium ion migration channel is enlarged, and the discharge specific capacity of the material is improved.
In 2002, chiang Yet-Mi, a labor force of MassachusettsThe first report by professor ng et al that LiFePO can be greatly improved by doping modification at lithium site 4 Electron conductivity. They carry out high valence metal ions (Mg) at the lithium site 2+ 、Al 3+ 、Ti 4+ 、Zr 4+ 、Nb 5+ And W 6+ ) Solid solution doping, electron conductivity improved by 8 orders of magnitude. Research shows that lithium site doping can improve the conductivity of the material, but doping atoms can block the diffusion of lithium ions in a one-dimensional channel, so that the high-rate charge and discharge performance of the material is not improved, and iron site doping can improve LiFePO 4 The multiplying power charge-discharge performance of the battery is improved, and the cycle performance is improved.
The improvement of material performance by titanium-doped ferric phosphate/lithium iron phosphate has attracted attention, for example, CN102361076A adopts solid phase ball milling technology to prepare titanium and barium-activated lithium iron phosphate LiTi x Ba y FePO 4 However, the solid phase ball milling process cannot ensure uniform dispersion of Ti therein; CN 108083330A uses titanium tetrachloride as a titanium source, dissolves metallic iron in hydrochloric acid solution to prepare a mixed solution of ferrous chloride and titanium tetrachloride, the mixed solution is added into a high-temperature sealing furnace in a spraying manner at 700-800 ℃ for reaction, and ferroferric oxide solid particles doped with nano titanium dioxide are collected, wherein the corrosion resistance of equipment is very high due to hydrogen chloride gas which is a high-temperature byproduct; CN 111498825A proposes that titanium tetrachloride reacts with phosphoric acid solution to prepare titanium phosphate solid, and then the titanium phosphate solid reacts with lithium carbonate and ferrous sulfate, but chloride ions in the titanium phosphate are difficult to remove fully in the process, and the performance of the final lithium iron phosphate anode material is affected by high chlorine content.
In conclusion, the development of the preparation method of the iron phosphate with simple process operation, wide raw material source and stable titanium element doping is very important.
In view of the above, the present invention is particularly proposed.
Disclosure of Invention
An object of the present invention is to provide a method for preparing titanium-doped battery-grade iron phosphate, so as to solve the above technical problems.
The invention also aims to provide the titanium-doped battery-grade iron phosphate prepared by the preparation method of the titanium-doped battery-grade iron phosphate.
In order to achieve the above purpose of the present invention, the following technical solutions are adopted:
a preparation method of titanium doped battery grade iron phosphate comprises the following steps:
adding iron-containing titanium ore into a ferrous sulfate solution to obtain a first mixed system; shunting and adding the first mixed system and a phosphate solution into a reaction container to obtain a second mixed system; adding a catalyst into the second mixed system, and introducing oxygen-containing gas to perform catalytic oxidation reaction to obtain a third mixed system; carrying out solid-liquid separation on the third mixed system, collecting solid matters, washing and drying;
the ferrous sulfate is a byproduct in the production process of titanium dioxide by a sulfuric acid method; the ferrous sulfate solution also contains titanium element;
the adding time of the iron-titanium containing ore is 4-8 min.
In one embodiment, the adding the iron-containing titanium ore to the ferrous sulfate solution specifically includes: adding iron-containing titanium ore into the ferrous sulfate solution within 1-2 min until the adding amount of the iron-containing titanium ore is 30-50% of the total amount of the iron-containing titanium ore; adding the rest ferruginous titanium ore at constant speed for 3-6 min.
In one embodiment, the concentration of ferrous sulfate in the ferrous sulfate solution is 0.5 to 2mol/L.
In one embodiment, the ferrous sulfate solution has a pH of 0.3 to 0.7.
In one embodiment, the ferrous sulfate solution has a mass ratio of iron element to titanium element of (480 to 520): 1.
in one embodiment, the amount of the titaniferous ore added is (1.05 to 1.60) in terms of a molar ratio of titanium dioxide in the titaniferous ore to hydrogen in the ferrous sulfate solution: 1.
in one embodiment, the phosphate salt solution comprises ammonium dihydrogen phosphate and/or sodium dihydrogen phosphate.
In one embodiment, the phosphate solution has a concentration of 0.5 to 2mol/L.
In one embodiment, the flow ratio of the first mixed system to the phosphate solution is 1: (0.5-2).
In one embodiment, the temperature within the reaction vessel is controlled to be in the range of 60 to 100 ℃.
In one embodiment, the first mixed system and the phosphate solution are added to the reaction vessel in separate flows for 1 to 3 hours.
In one embodiment, the catalyst is sodium nitrite.
In one embodiment, the amount of the catalyst added is 0.05% to 0.5% by mass of the iron element in the second mixed system.
In one embodiment, before adding the catalyst to the second mixed system, the method further comprises: adjusting the pH of the second system to 0.48-0.55.
In one embodiment, the oxygen-containing gas comprises oxygen in an amount of 33% to 35% by volume.
In one embodiment, the mass of the oxygen-containing gas introduced is 1 to 1.5 times the mass of the iron element in the second mixed system.
In one embodiment, the temperature of the catalytic oxidation reaction is 80 to 120 ℃; the time of the catalytic oxidation reaction is 24-30 h.
In one embodiment, the iron-titanium bearing ore comprises high titanium slag and/or reduced titanomagnetite.
The titanium-doped battery-grade iron phosphate is prepared by the preparation method of the titanium-doped battery-grade iron phosphate.
In one embodiment, the doped amount of titanium is 1813 to 2000ppm.
In one embodiment, the titanium-doped battery grade iron phosphate has an average particle size of 1 to 10 μm;
in one embodiment, the titanium-doped battery grade iron phosphate has a tap density of 0.7 to 1.2g/cm 3 。
Preferably, the iron-to-phosphorus ratio of the titanium-doped battery-grade iron phosphate is 0.955 to 1.02.
Compared with the prior art, the invention has the beneficial effects that:
(1) The method takes the byproduct ferrous sulfate containing titanium in the production process of titanium white by a sulfuric acid method as a raw material, obtains a source containing the titaniferous iron by removing other impurities, realizes the optimal utilization of byproduct resources, and also realizes the uniform mixing of iron phosphate and titanium; by adjusting the system acidity, impurities are removed directionally, part of titanium is reserved, the high-efficiency separation of target impurities is realized, and the high purity of the iron phosphate is also ensured; reducing H by using iron-containing titanium ore as reducing agent + And Fe 3+ After the reduction reaction, the acidity is reduced, fe 2+ The concentration is increased, and the yield of the iron phosphate is improved; meanwhile, in the reduction process, the Fe simple substance in the reduced titanium ore is consumed, the Ti content is improved to more than 85 percent, the grade requirement of the raw material synthesized rutile titanium produced by the titanium dioxide produced by the chloride process of a company is met, and the reduced titanium ore can be used as the raw material titanium ore produced by the chloride process to realize the comprehensive utilization of Fe resources; the air catalytic oxidation process is not suitable for oxidants such as hydrogen peroxide/sodium chlorate and the like, so that the material consumption is reduced, the oxidation efficiency is ensured, and the process is convenient to scale up.
(2) The invention solves the problem of solid waste treatment in the traditional titanium dioxide production, improves the grade of titanium ore which is a raw material for producing titanium dioxide by a chlorination method, and obtains an iron phosphate product with high economic value; the method has the advantages of environmental protection, low cost and the like, and has great industrial application value; the obtained titanium doped battery grade iron phosphate is uniform and stable in doping and high in purity.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a scanning electron microscope image of titanium doped battery grade iron phosphate in example 1 of the present invention under a condition of 5000 times magnification;
fig. 2 is a scanning electron microscope image of the titanium-doped battery grade iron phosphate in example 1 of the present invention under a magnification of 30000 times;
FIG. 3 is a scanning electron micrograph of iron phosphate according to comparative example 2 of the present invention magnified 5000 times;
fig. 4 is a scanning electron micrograph of the iron phosphate according to comparative example 2 of the present invention magnified 30000 times.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.
According to one aspect of the invention, the invention relates to a method for preparing titanium doped battery grade iron phosphate, which comprises the following steps:
adding iron-containing titanium ore into the ferrous sulfate solution to obtain a first mixed system; shunting and adding the first mixed system and a phosphate solution into a reaction container to obtain a second mixed system; adding a catalyst into the second mixed system, and introducing oxygen-containing gas to perform a catalytic oxidation reaction to obtain a third mixed system; carrying out solid-liquid separation on the third mixed system, collecting solid matters, washing and drying;
the ferrous sulfate is a byproduct in the production process of titanium dioxide by a sulfuric acid method; the ferrous sulfate solution also contains titanium element;
the adding time of the iron-titanium containing ore is 4-8 min.
The method takes the ferrous sulfate byproduct produced in the production process of titanium white by a sulfuric acid method as a raw material, removes impurities in the preparation process of the iron phosphate through the operation, retains a small amount of titanium and the iron phosphate to be uniformly co-precipitated, realizes the doping of the ortho-acid, has mild reaction conditions and low cost, and meets the requirements of industrial production.
The invention relates to a method for preparing iron-containing titanium oreFe simple substance of (1) and H in ferrous sulfate solution + Reacting, reducing the acidity of the solution, increasing the pH value to 2.3-4.5, promoting the hydrolysis of a small part of Ti, and then carrying out settling separation. The iron-containing titanium ore needs to be rapidly added into ferrous sulfate solution, so that a large amount of iron simple substances in the reduced titanium can reduce part of Ti into Ti 3+ Ions of Ti 3+ The Ti is uniformly distributed in the ferrous sulfate solution, so that the Ti is prevented from being completely hydrolyzed, and the doping amount of the Ti is reduced; reducing Fe in titanium ore 3+ Avoiding Fe (OH) 3 Generation and reduction of Fe (OH) in the product 3 Impurities; and Mg, al and the like form hydroxide precipitates after the pH value of the solution is increased, and can be removed through settling separation; in addition, in the reaction, the Fe content in the reduced titanium can be reduced, the titanium grade of the reduced titanium of a company is improved to more than 85 percent, and the reduced titanium ore with the improved titanium grade can be used as a raw material for producing titanium dioxide by a chlorination process of the company to synthesize rutile.
In one embodiment, the adding the iron-containing titanium ore to the ferrous sulfate solution specifically includes: adding iron-containing titanium ore into the ferrous sulfate solution within 1-2 min until the adding amount of the iron-containing titanium ore is 30-50% of the total amount of the iron-containing titanium ore; the rest iron-titanium ore is added at a constant speed, and the time for adding at the constant speed is 3-6 min.
Due to iron simple substance and H + The reaction will form H 2 In the reaction process, attention is paid to emptying because the reaction cannot be closed; in one embodiment, the mass content of elemental iron in the ilmenite is 30% to 40%; the addition of the ilmenite is controlled through the specific feeding rate, and the ilmenite is quickly added in the early stage of the reaction, so that the iron elementary substance part in the ilmenite and the H in the ferrous sulfate solution can be enabled + The TiO in the ferrous sulfate solution can be quickly reacted when the iron simple substance which cannot react with the iron simple substance 2 Reduction to Ti 3+ Thereby ensuring that the pH is raised while the TiO is simultaneously 2 May be made of Ti 3+ Is present in solution, and Al 3+ And other metal ions form hydroxide precipitate in the process of increasing the pH value, so that the aim of removing other metal ion impurities in the ferrous sulfate is fulfilled, and the aim of retaining Ti is fulfilled.
In one embodiment, the ferrous sulfate solution has a pH of 0.3 to 0.7, e.g., 0.4, 0.5, 0.6, 0.7, etc.
In one embodiment, the concentration of the ferrous sulfate in the ferrous sulfate solution is 0.5 to 2mol/L, preferably 1 to 1.5mol/L; for example, 0.6mol/L, 0.7mol/L, 0.8mol/L, 0.9mol/L, 1mol/L, 1.2mol/L, 1.5mol/L, 1.8mol/L, or 2mol/L. The low concentration of the ferrous sulfate solution affects the production efficiency, and the high concentration of the ferrous sulfate solution is easy to cause Fe precipitation. In one embodiment, the mixed solution containing ferrous sulfate is obtained by dissolving ferrous sulfate crystals which are a byproduct in titanium dioxide production. In one embodiment, the mixed liquor containing ferrous sulfate is a ferrous sulfate solution from spent acid leaching, thereby ensuring that the ferrous solution contains a portion of titanyl sulfate.
In one embodiment, the iron-containing titaniferous ore includes at least one of commercially available reduced titaniferous ore, high-titanium slag, reduced titanomagnetite.
In one embodiment, the iron-containing titanium ore contains 26-30% of simple substance iron and TiO 2 52 to 62 percent of (A), 5 to 8 percent of FeO, 1.5 to 2.5 percent of MnO, and Al 2 O 3 The mass content of (A) is 1-1.5%.
In one embodiment, the ferrous sulfate solution has a mass ratio of iron element to titanium element of (480 to 520): 1.
in one embodiment, the amount of the iron-titanium-containing ore added is (1.05 to 1.60) in terms of a molar ratio of titanium dioxide in the iron-titanium-containing ore to hydrogen in the ferrous sulfate solution: 1, e.g. 1.05.
In one embodiment, the phosphate salt solution comprises ammonium dihydrogen phosphate and/or sodium dihydrogen phosphate. The invention adopts acid salt as raw material to ensure that the pH value of the system is between 1.8 and 3.5, which is beneficial to the stability of the whole system.
In one embodiment, the phosphate solution has a concentration of 0.5 to 2mol/L, preferably 1 to 1.5mol/L. In one embodiment, the phosphate solution concentration includes, but is not limited to, 0.6, 0.7, 0.8, 0.9, 1, 1.2, 1.5, 1.8, or 2mol/L, and the like.
In one embodiment, the flow ratio of the first mixed system to the phosphate solution is 1: (0.5-2).
The invention can directionally remove impurities by adjusting the system acidity, retain partial titanium, realize high-efficiency separation of target impurities and ensure the high purity of the iron phosphate.
In one embodiment, the temperature within the reaction vessel is controlled to be 60 to 100 ℃, such as 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 100 ℃ and the like.
In one embodiment, the first mixed system and the phosphate solution are added to the reaction vessel in divided streams for 1 to 3 hours, such as 1.2 hours, 1.5 hours, 1.8 hours, 2 hours, 2.5 hours, 3 hours, and the like.
In one embodiment, the catalyst is sodium nitrite.
In one embodiment, the amount of the catalyst added is 0.05% to 0.5% by mass of the iron element in the second mixed system. For example, 0.1%, 0.15%, 0.2%, 2.5%, 0.3%, 0.35%, 0.4%, 0.5%, etc.
In one embodiment, before adding the catalyst to the second mixed system, the method further comprises: adjusting the pH of the second system to 0.48 to 0.55.
The invention adopts oxygen-containing gas to carry out catalytic oxidation process, does not use oxidants such as hydrogen peroxide/sodium chlorate and the like, reduces material consumption, ensures oxidation efficiency and is convenient for large-scale process amplification.
In one embodiment, the oxygen-containing gas comprises oxygen in an amount of 33% to 35% by volume, such as 33%, 33.5%, 34%, 34.5%, 35%, or the like.
In one embodiment, the oxygen-containing gas is air.
In one embodiment, the mass of the oxygen-containing gas introduced is 1 to 1.5 times, for example, 1 time, 1.2 times, 1.3 times, 1.5 times, or the like, the mass of the iron element in the second mixed system.
In one embodiment, the temperature of the catalytic oxidation reaction is 80 to 120 ℃, such as 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, 110 ℃, 120 ℃ and the like. In one embodiment, the time for the catalytic oxidation reaction is 24 to 30 hours. Such as 24h, 25h, 26h, 27h, 28h, 29h, 30h, etc. Through proper reaction temperature and time, the materials are ensured to fully react, the reaction efficiency is improved, and the purity of the product is improved.
According to another aspect of the invention, the invention also relates to the titanium doped battery grade iron phosphate prepared by the preparation method of the titanium doped battery grade iron phosphate.
In one embodiment, the titanium doped battery grade iron phosphate has an average particle size of 1 to 10 μm. For example, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, etc.
In one embodiment, the tap density of the titanium-doped battery grade iron phosphate is 2.35 to 2.4g/cm 3 。
The titanium-doped battery-grade iron phosphate prepared by the method has dispersed particles and uniform size.
In the titanium-doped battery-grade iron phosphate obtained by the invention, by mass percentage, the content of Fe is 35.8-36.6%, the content of P is 20.5-21.1%, and the content of Fe/P is 0.955-1.02; the doping amount of Ti is 1813-2000 ppm; ca is less than or equal to 100ppm, mg is less than or equal to 100ppm, zn is less than or equal to 10ppm, cu is less than or equal to 10ppm, mn is less than or equal to 100ppm, cr is less than or equal to 50ppm, K is less than or equal to 50ppm, co is less than or equal to 50ppm, al is less than or equal to 50ppm. In one embodiment, the amount of Ti doped is 1815ppm, 1850ppm, 1880ppm, 1900ppm, and the like.
The following is a further explanation with reference to specific examples and comparative examples.
Example 1
The preparation method of the titanium-doped battery-grade iron phosphate comprises the following steps:
(1) Weighing 1000g of titanium-containing ferrous sulfate (Fe is 17.92%) which is a byproduct in the production process of titanium white by a sulfuric acid method to prepare a 1mol/L solution, heating the solution at a water bath temperature of 50 ℃, and adding Mornebick reduced titanium ore (the molar ratio of the added reduced titanium ore is H: H) + ：TiO 2 1.05, and the adding time of the iron-titanium-containing ore is 5min, wherein the iron-titanium-containing ore is added into the ferrous sulfate solution within the first 2min to the iron-titanium-containing oreThe adding amount is 50 percent of the total amount; adding the rest iron-containing titanium ore at constant speed; the mass content of simple substance iron in the reduced titanium ore is 28.85 percent, and TiO 2 56.53% by mass of (1), 7% by mass of FeO, 2.047% by mass of MnO, and Al 2 O 3 The mass content of the titanium dioxide is 1.087 percent, a large amount of bubbles in the ferrous sulfate solution in the adding process need to be reacted by a container with larger volume, the ferrous sulfate solution gradually changes to blue-purple, 1mL of the solution is taken for dilution, the solution is a clear solution, namely, the impurity Ti is reduced into Ti 3+ Continuously stirring at 70 deg.C, controlling pH of reaction system to 3.58, filtering to remove unreacted titanium ore, reacting the filtrate at 70 deg.C for 1.5 hr to obtain Al in the solution 3+ And a small amount of soluble titanium is gradually hydrolyzed into metatitanic acid (H) at high temperature 2 TiO 3 ) And Al (OH) 3 Precipitating, gradually generating white precipitate in the reaction solution in the heat preservation process, standing for 4h, filtering to remove impurities to obtain a clear ferrous sulfate solution, measuring the concentration of ferrous ions in the ferrous sulfate purification, and calculating the recovery rate of Fe in the purification process to be 96.37%.
(2) Preparing 1mol/L sodium dihydrogen phosphate solution, wherein the ratio of the total Fe to the total P is 1.05:1 adding two groups of liquid into a reaction kettle at the same time according to a certain flow rate ratio; adjusting the pH value to 0.50 by using phosphoric acid, adding 0.1 percent of sodium nitrate by taking the mass content of Fe element in the solution as a reference, and bubbling into oxygen-enriched air (O) which is a byproduct of a cryogenic air separation unit 2 Content of 34%), the input amount is 1.2 times of the total amount of Fe, the temperature of the reaction system is raised to 100 ℃, the reaction is carried out for 30 hours at constant temperature, suspension of hydrated iron phosphate is obtained, liquid-solid separation is carried out, pure water is washed until barium chloride solution is detected to have no sulfate ions, and the hydrated iron phosphate product is obtained after drying. The sample was taken for ICP full component detection, fe/P was calculated, tap density was measured, and the results are shown in Table 1.
The scanning electron microscope image of the titanium-doped cell-grade iron phosphate in example 1 under the condition of 5000 times magnification is shown in fig. 1, and the scanning electron microscope image under the condition of 30000 times magnification is shown in fig. 2.
Example 2
The preparation method of the titanium-doped battery-grade iron phosphate comprises the following steps:
(1) Weighing 1000g of titanium-containing ferrous sulfate (Fe is 17.92%) which is a byproduct in the production process of titanium white by a sulfuric acid method to prepare a solution with the concentration of 1mol/L, heating the solution at a water bath temperature of 50 ℃, adding Mosangbicg reduced titanium ore, and adding the molar ratio of the reduced titanium ore: h + ：TiO 2 1.05, the mass content of the simple substance iron in the reduced titanium ore is 28.85%, and the mass content of the simple substance iron in the reduced titanium ore is TiO 2 56.53 percent of mass content, 7 percent of FeO mass content, 2.047 percent of MnO mass content, and Al 2 O 3 The mass content is 1.087%, the adding time of the reduced titanium ore is 5min, wherein the iron-containing titanium ore is added into the ferrous sulfate solution within the first 2min until the adding amount of the iron-containing titanium ore is 30% of the total amount of the iron-containing titanium ore; adding the rest iron-containing titanium ore at constant speed; a large amount of bubbles in the ferrous sulfate solution in the adding process need to be reacted by a container with larger volume; the ferrous sulfate solution gradually changes to bluish purple, and after 1mL of the solution is diluted, the solution is a clear solution, namely the impurity Ti is reduced to Ti 3+ Continuously stirring at 70 deg.C, adjusting pH to 3.55, filtering to remove unreacted titanium ore, reacting the filtrate at 70 deg.C for 1.5 hr to obtain Al in the solution 3+ And a small amount of soluble titanium is gradually hydrolyzed into metatitanic acid (H) at high temperature 2 TiO 3 ) And Al (OH) 3 Precipitating, gradually generating white precipitates in the reaction solution in the heat preservation process, filtering and removing impurities to obtain a clear ferrous sulfate solution, measuring the concentration of ferrous ions in the ferrous sulfate purification, and calculating the recovery rate of Fe in the purification process to be 96.24%.
(2) Preparing 1mol/L sodium dihydrogen phosphate solution, wherein the ratio of the total Fe to the total P is 1.05:1, simultaneously adding two groups of liquid into a reaction kettle according to a certain flow rate ratio; adjusting the pH value to 0.52 by using phosphoric acid, adding 0.1 percent of sodium nitrate based on the mass content of Fe element in the solution, and bubbling the solution into oxygen-enriched air (O) which is a byproduct of a cryogenic air separation unit 2 Content of 34%), the input amount is 1.2 times of the total amount of Fe, the temperature of the reaction system is raised to 100 ℃, the reaction is carried out for 30 hours at constant temperature, suspension of hydrated iron phosphate is obtained, liquid-solid separation is carried out, pure water is washed until barium chloride solution is detected to have no sulfate ions, and the hydrated iron phosphate product is obtained after drying. Sampling, detecting ICP all-component, calculating Fe/P, tap density was measured, and the results are shown in Table 1.
Comparative example 1
Weighing 1000g of ferrous sulfate (17.92% of Fe) to prepare a 1mol/L solution, heating the solution at 70 ℃ in a hot water bath, adding reduced titanium ore, wherein the molar ratio of the added reduced titanium ore is as follows: h + ：TiO 2 1.05, adding reduced titanium ore for 30min, wherein a small amount of bubbles in a ferrous sulfate solution are adopted in the adding process, the ferrous sulfate solution gradually becomes turbid, the tyndall effect appears after flashlight irradiation, namely impurities such as Ti, al and the like start to hydrolyze, stirring is continuously carried out in the process, the temperature is 70 ℃, the pH value of a reaction system is adjusted to be 3.78, unreacted titanium ore is removed by filtration, and the filtrate is subjected to constant temperature reaction for 1.5h at 70 ℃ so as to enable soluble Titanium (TiOSO) in the solution to be dissolved 4 Mainly) is gradually hydrolyzed into metatitanic acid (H) at high temperature 2 TiO 3 ) Separating liquid from solid to obtain ferrous sulfate purified liquid; the concentration of ferrous ions in the ferrous sulfate purification is measured, and the recovery rate of Fe in the purification process is calculated to be 95.83%.
Preparing 1mol/L sodium dihydrogen phosphate solution, wherein the ratio of the total Fe to the total P is 1.05:1, adding two groups of liquid into a reaction kettle at the same time according to a certain flow rate ratio, dropwise adding 30 percent hydrogen peroxide solution with the ferrous ion total amount being 1.2 times of that of the ferrous ion to oxidize the ferrous ion into the ferric ion, and keeping the reaction temperature at 45 +/-2 ℃. Adjusting the pH value to 0.51 by using 85% phosphoric acid, raising the temperature of a reaction system to 95 ℃, carrying out constant-temperature reflux reaction for 24 hours to obtain a suspension of hydrated iron phosphate, carrying out liquid-solid separation, washing with pure water until barium chloride solution detects no sulfate ions, and drying to obtain a hydrated iron phosphate product. The sample was taken for ICP full component detection, fe/P was calculated, tap density was measured, and the results are shown in Table 1.
Comparative example 2
Weighing 1000g ferrous sulfate (Fe is 17.92%) to prepare 1mol/L solution, heating in hot water bath at 70 deg.C and pH of 2.37, and reacting at constant temperature for 1.5 hr to make soluble Titanium (TiOSO) in the solution 4 Mainly) of Al 3+ Gradually hydrolyzed into metatitanic acid (H) at high temperature 2 TiO 3 ) And Al (OH) 3 Precipitating, filtering to remove impurities to obtain clear ferrous sulfate solution, and measuring the concentration of ferrous ions in ferrous sulfate purificationThe calculated recovery of Fe in the purification process was 97.88%.
Preparing 1mol/L sodium dihydrogen phosphate solution, wherein the ratio of the total Fe to the total P is 1.05:1, simultaneously adding two groups of liquid into a reaction kettle at a certain flow rate ratio, dropwise adding 30% hydrogen peroxide solution with the ferrous ion amount being 1.2 times of the total ferrous ion amount to oxidize ferrous ions into ferric ions, adjusting the pH value to be 0.49 by using phosphoric acid, raising the temperature of a reaction system to 95 ℃, carrying out constant-temperature reflux reaction for 28 hours to obtain suspension of hydrated ferric phosphate, carrying out liquid-solid separation, washing with pure water until barium chloride solution detects that sulfate ions are not contained, and drying to obtain a hydrated ferric phosphate product. The sample was taken for ICP full component detection, fe/P was calculated, tap density was measured, and the results are shown in Table 1.
The scanning electron micrograph of the iron phosphate in this comparative example at 5000 times magnification is shown in fig. 3, and the scanning electron micrograph at 30000 times magnification is shown in fig. 4.
Examples of the experiments
1. The index results of iron phosphate in examples and comparative examples are shown in table 1.
TABLE 1 index test results for titanium-doped iron phosphate
| Index (I) | Example 1 | Example 2 | Comparative example 1 | Comparative example 2 | Commercially available LB-01 |
| Fe％ | 36.59 | 35.73 | 36.62 | 36.01 | 36.64 |
| P％ | 20.55 | 19.59 | 20.94 | 20.90 | 20.91 |
| Fe/P | 0.987 | 1.012 | 0.969 | 0.956 | 0.972 |
| Tap density g/cm 3 | 0.98 | 0.83 | 0.91 | 0.94 | 0.87 |
| Ca(ppm) | 9 | 13 | 18 | 35 | 5 |
| Mg(ppm) | 18 | 45 | 53 | 39 | 51 |
| Na(ppm) | 11 | 17 | 33 | 18 | 2 |
| Ni(ppm) | Not detected out | Not detected out | Not detected out | Not detected out | Not detected out |
| Zn(ppm) | 4 | 1 | 3 | 4 | 18 |
| Cu(ppm) | 3 | 4 | 6 | 4 | 8 |
| Mn(ppm) | 30 | 37 | 29 | 43 | 26 |
| Pb(ppm) | Not detected out | Not detected out | Not detected out | Not detected out | Not detected out |
| Cr(ppm) | 6 | 4 | 7 | 6 | 2 |
| K(ppm) | 29 | 26 | 34 | 23 | 24 |
| Co(ppm) | 1 | 5 | 3 | 1 | 10 |
| Al(ppm) | 14 | 27 | 18 | 968 | 31 |
| Ti(ppm) | 1856 | 1813 | 39 | 1915 | 22 |
2. Respectively preparing lithium iron phosphate from the iron phosphate obtained in the embodiment and the comparative example, and respectively preparing button cells from the lithium iron phosphate, wherein the specific methods are as follows:
preparing lithium iron phosphate: drying the obtained iron phosphate (Fe PO) 4 ) Solid, glucose (C) 6 H 12 O 6 ) And mixing the lithium carbonate, pouring the mixture into absolute ethyl alcohol, and performing ball milling for 20 hours by using a planetary ball mill. Taking out the slurry, drying, grinding, roasting at 700 ℃ for 10h in a tubular furnace under the nitrogen atmosphere, and performing carbothermic reduction to obtain LiFePO 4 。
Preparing a button cell: PVDF, acetylene black, and LiFePO were mixed in a mass ratio of 1 4 Adding N-methyl pyrrolidone into the powder to prepare slurry, uniformly coating the slurry on an aluminum foil, carrying out vacuum drying, taking out, rolling and punching to form a circular electrode plate with the diameter of 12 mm. The button cell was assembled in a glove box (high purity Ar atmosphere) with an electrolyte comprising: 1mol/L LiPF 6 The volume ratio of the mixed solution of DCM, EC and EMC is 1. And (3) carrying out constant current charge-discharge cycle test on the button cell, wherein the charge-discharge voltage is 2.5-4.2V. The results are shown in Table 2.
Table 2 electrochemical performance test results of lithium iron phosphate prepared in examples and comparative examples
As can be seen from Table 1, in the preparation method of iron phosphate, the doping amount of Ti can be effectively controlled by setting the addition rate of the reduced titanium ore, al impurities are removed, the prepared iron phosphate meets the requirements of the market, and the contents of Al and Ti in comparative example 1 and comparative example 2 do not reach the expectation; meanwhile, in the oxidation precipitation stage, a bubbling oxygen-enriched air catalytic oxidation mode is adopted, the oxidation effect is achieved, the iron-phosphorus ratio is ensured, and compared with the comparative example 1, the use amount of hydrogen peroxide is reduced, and the cost is reduced.
As can be seen from table 2, the rate performance of the lithium iron phosphate prepared in the embodiments 1 and 2 of the present invention is significantly improved and is superior to that of the commercially available product, and the compaction density is equivalent to that of the commercially available product; the rate performance of the comparative examples 1 and 2 is obviously lower than that of the commercial product, and the rate performance of the lithium iron phosphate can be effectively improved after the ferric phosphate is subjected to ortho-acid doping with Ti.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A preparation method of titanium doped battery grade iron phosphate is characterized by comprising the following steps:
adding iron-containing titanium ore into a ferrous sulfate solution to obtain a first mixed system; shunting and adding the first mixed system and a phosphate solution into a reaction container to obtain a second mixed system; adding a catalyst into the second mixed system, and introducing oxygen-containing gas to perform catalytic oxidation reaction to obtain a third mixed system; carrying out solid-liquid separation on the third mixed system, collecting solid matters, washing and drying;
the ferrous sulfate is a byproduct in the production process of titanium dioxide by a sulfuric acid method; the ferrous sulfate solution also contains titanium element;
the adding time of the iron-titanium containing ore is 4-8 min.
2. The method for preparing titanium-doped battery-grade iron phosphate according to claim 1, wherein the adding of the iron-containing titanium ore to the ferrous sulfate solution specifically comprises: adding iron-containing titanium ore into the ferrous sulfate solution within 1-2 min until the adding amount of the iron-containing titanium ore is 30-50% of the total amount of the iron-containing titanium ore; the rest iron-titanium ore is added at a constant speed, and the time for adding at the constant speed is 3-6 min.
3. The method of preparing titanium-doped battery grade iron phosphate according to claim 1, characterized by comprising at least one of the following features (1) to (4):
(1) In the ferrous sulfate solution, the concentration of ferrous sulfate is 0.5-2 mol/L;
(2) The pH value of the ferrous sulfate solution is 0.3-0.7;
(3) In the ferrous sulfate solution, the mass ratio of the iron element to the titanium element is (480-520): 1;
(4) The addition amount of the iron-titanium-containing ore is (1.05-1.60) in terms of the molar ratio of titanium dioxide in the iron-titanium-containing ore to hydrogen in the ferrous sulfate solution: 1.
4. the method of preparing titanium-doped battery grade iron phosphate according to claim 1, characterized by comprising at least one of the following features (1) to (3):
(1) In the phosphate solution, the phosphate comprises ammonium dihydrogen phosphate and/or sodium dihydrogen phosphate;
(2) The concentration of the phosphate solution is 0.5-2 mol/L;
(3) The flow ratio of the first mixing system to the phosphate solution is 1: (0.5-2).
5. The method of preparing titanium-doped battery grade iron phosphate according to claim 1, characterized by comprising at least one of the following features (1) to (2):
(1) Controlling the temperature in the reaction container to be 60-100 ℃;
(2) The time for shunting and adding the first mixed system and the phosphate solution into the reaction container is 1-3 h.
6. The method for preparing titanium-doped battery grade iron phosphate according to claim 1, characterized by comprising at least one of the following features (1) to (3):
(1) The catalyst is sodium nitrite;
(2) The addition amount of the catalyst is 0.05-0.5% of the mass of the iron element in the second mixed system;
(3) Before adding the catalyst into the second mixed system, the method further comprises the following steps: adjusting the pH of the second system to 0.48-0.55.
7. The method of preparing titanium-doped battery grade iron phosphate according to claim 1, characterized by comprising at least one of the following features (1) to (3):
(1) In the oxygen-containing gas, the volume content of oxygen is 33-35%;
(2) The mass of the oxygen-containing gas is 1 to 1.5 times of the mass of the iron element in the second mixed system.
8. The method for preparing titanium-doped battery-grade iron phosphate according to claim 1, wherein the temperature of the catalytic oxidation reaction is 80-120 ℃; the time of the catalytic oxidation reaction is 24-30 h.
9. The method of making titanium-doped battery-grade iron phosphate according to claim 1, wherein the iron-titanium-bearing ore comprises high-titanium slag and/or reduced titanomagnetite.
10. The titanium-doped battery-grade iron phosphate prepared by the method for preparing titanium-doped battery-grade iron phosphate according to any one of claims 1 to 9;
preferably, the doping amount of the titanium is 1813-2000 ppm;
preferably, the average particle size of the titanium-doped battery-grade iron phosphate is 1-10 μm;
preferably, the tap density of the titanium-doped battery-grade iron phosphate is 0.7-1.2 g/cm 3 ；
Preferably, the iron-to-phosphorus ratio of the titanium-doped battery-grade iron phosphate is 0.955 to 1.02.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116287785A (en) * | 2023-03-24 | 2023-06-23 | 甘肃佰利联化学有限公司 | Method for preparing trivalent titanium by reduction of ferric phosphate-titanium co-production process |
| CN117756076A (en) * | 2023-12-22 | 2024-03-26 | 湖北虹润高科新材料有限公司 | Titanium-doped anhydrous ferric phosphate material, and preparation method and application thereof |
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| CN101531355A (en) * | 2009-04-22 | 2009-09-16 | 广西大学 | Method for preparing high purity ferric phosphate using ferrous sulfate as by-product of white titanium pigment |
| CN113611863A (en) * | 2021-07-30 | 2021-11-05 | 中南大学 | Cation-doped lithium iron phosphate positive electrode material and preparation method and application thereof |
| CN114671421A (en) * | 2022-04-29 | 2022-06-28 | 中国科学院过程工程研究所 | Method and system for preparing iron phosphate by recycling iron-containing hydrochloric acid pickling waste liquid |
| CN115367725A (en) * | 2022-08-29 | 2022-11-22 | 广东邦普循环科技有限公司 | Doped lithium iron phosphate and preparation method and application thereof |
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| CN101531355A (en) * | 2009-04-22 | 2009-09-16 | 广西大学 | Method for preparing high purity ferric phosphate using ferrous sulfate as by-product of white titanium pigment |
| CN113611863A (en) * | 2021-07-30 | 2021-11-05 | 中南大学 | Cation-doped lithium iron phosphate positive electrode material and preparation method and application thereof |
| CN114671421A (en) * | 2022-04-29 | 2022-06-28 | 中国科学院过程工程研究所 | Method and system for preparing iron phosphate by recycling iron-containing hydrochloric acid pickling waste liquid |
| CN115367725A (en) * | 2022-08-29 | 2022-11-22 | 广东邦普循环科技有限公司 | Doped lithium iron phosphate and preparation method and application thereof |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116287785A (en) * | 2023-03-24 | 2023-06-23 | 甘肃佰利联化学有限公司 | Method for preparing trivalent titanium by reduction of ferric phosphate-titanium co-production process |
| CN117756076A (en) * | 2023-12-22 | 2024-03-26 | 湖北虹润高科新材料有限公司 | Titanium-doped anhydrous ferric phosphate material, and preparation method and application thereof |
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