CN114204021A - Preparation method of low-cost lithium iron manganese phosphate - Google Patents
Preparation method of low-cost lithium iron manganese phosphate Download PDFInfo
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- CN114204021A CN114204021A CN202111307829.2A CN202111307829A CN114204021A CN 114204021 A CN114204021 A CN 114204021A CN 202111307829 A CN202111307829 A CN 202111307829A CN 114204021 A CN114204021 A CN 114204021A
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- DVATZODUVBMYHN-UHFFFAOYSA-K lithium;iron(2+);manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[Fe+2].[O-]P([O-])([O-])=O DVATZODUVBMYHN-UHFFFAOYSA-K 0.000 title claims abstract description 48
- 238000002360 preparation method Methods 0.000 title claims abstract description 14
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 claims abstract description 81
- 239000000463 material Substances 0.000 claims abstract description 62
- 239000002002 slurry Substances 0.000 claims abstract description 62
- 238000000034 method Methods 0.000 claims abstract description 61
- 238000006243 chemical reaction Methods 0.000 claims abstract description 57
- 239000002244 precipitate Substances 0.000 claims abstract description 50
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 claims abstract description 35
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 30
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 30
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 claims abstract description 30
- 229910000616 Ferromanganese Inorganic materials 0.000 claims abstract description 29
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 claims abstract description 27
- 229910052808 lithium carbonate Inorganic materials 0.000 claims abstract description 27
- MCDLETWIOVSGJT-UHFFFAOYSA-N acetic acid;iron Chemical compound [Fe].CC(O)=O.CC(O)=O MCDLETWIOVSGJT-UHFFFAOYSA-N 0.000 claims abstract description 26
- 238000005245 sintering Methods 0.000 claims abstract description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 19
- 238000000227 grinding Methods 0.000 claims abstract description 18
- GFNGCDBZVSLSFT-UHFFFAOYSA-N titanium vanadium Chemical compound [Ti].[V] GFNGCDBZVSLSFT-UHFFFAOYSA-N 0.000 claims abstract description 17
- 239000002245 particle Substances 0.000 claims abstract description 16
- 238000001694 spray drying Methods 0.000 claims abstract description 16
- 239000004254 Ammonium phosphate Substances 0.000 claims abstract description 13
- 229910000148 ammonium phosphate Inorganic materials 0.000 claims abstract description 13
- 235000019289 ammonium phosphates Nutrition 0.000 claims abstract description 13
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 claims abstract description 13
- 238000004806 packaging method and process Methods 0.000 claims abstract description 13
- 238000012216 screening Methods 0.000 claims abstract description 13
- 239000011261 inert gas Substances 0.000 claims abstract description 7
- 238000010902 jet-milling Methods 0.000 claims abstract description 7
- 239000012798 spherical particle Substances 0.000 claims abstract description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 62
- 239000000428 dust Substances 0.000 claims description 42
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 40
- 229910052757 nitrogen Inorganic materials 0.000 claims description 31
- 238000001035 drying Methods 0.000 claims description 28
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 23
- 239000010936 titanium Substances 0.000 claims description 23
- 229910052719 titanium Inorganic materials 0.000 claims description 23
- 229910052720 vanadium Inorganic materials 0.000 claims description 23
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 23
- 238000001354 calcination Methods 0.000 claims description 21
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 20
- 239000007789 gas Substances 0.000 claims description 20
- 229910052742 iron Inorganic materials 0.000 claims description 20
- 229910052744 lithium Inorganic materials 0.000 claims description 20
- 238000004321 preservation Methods 0.000 claims description 19
- 230000000630 rising effect Effects 0.000 claims description 18
- 238000003756 stirring Methods 0.000 claims description 18
- 239000000919 ceramic Substances 0.000 claims description 13
- 238000001914 filtration Methods 0.000 claims description 13
- 239000004744 fabric Substances 0.000 claims description 12
- 239000000706 filtrate Substances 0.000 claims description 12
- 239000007921 spray Substances 0.000 claims description 12
- CPSYWNLKRDURMG-UHFFFAOYSA-L hydron;manganese(2+);phosphate Chemical compound [Mn+2].OP([O-])([O-])=O CPSYWNLKRDURMG-UHFFFAOYSA-L 0.000 claims description 9
- 238000005406 washing Methods 0.000 claims description 9
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 claims description 7
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 claims description 7
- 235000012538 ammonium bicarbonate Nutrition 0.000 claims description 7
- 239000001099 ammonium carbonate Substances 0.000 claims description 7
- UNTBPXHCXVWYOI-UHFFFAOYSA-O azanium;oxido(dioxo)vanadium Chemical compound [NH4+].[O-][V](=O)=O UNTBPXHCXVWYOI-UHFFFAOYSA-O 0.000 claims description 7
- 229910000349 titanium oxysulfate Inorganic materials 0.000 claims description 7
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims description 6
- 229920002472 Starch Polymers 0.000 claims description 6
- CZMRCDWAGMRECN-UGDNZRGBSA-N Sucrose Chemical compound O[C@H]1[C@H](O)[C@@H](CO)O[C@@]1(CO)O[C@@H]1[C@H](O)[C@@H](O)[C@H](O)[C@@H](CO)O1 CZMRCDWAGMRECN-UGDNZRGBSA-N 0.000 claims description 6
- 229930006000 Sucrose Natural products 0.000 claims description 6
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 claims description 6
- 229910052921 ammonium sulfate Inorganic materials 0.000 claims description 6
- 235000011130 ammonium sulphate Nutrition 0.000 claims description 6
- 229910010293 ceramic material Inorganic materials 0.000 claims description 6
- 238000001816 cooling Methods 0.000 claims description 6
- 238000007599 discharging Methods 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- 230000002093 peripheral effect Effects 0.000 claims description 6
- 239000008107 starch Substances 0.000 claims description 6
- 235000019698 starch Nutrition 0.000 claims description 6
- 239000005720 sucrose Substances 0.000 claims description 6
- 238000009461 vacuum packaging Methods 0.000 claims description 6
- 235000012431 wafers Nutrition 0.000 claims description 3
- 229910002096 lithium permanganate Inorganic materials 0.000 description 6
- 150000001450 anions Chemical class 0.000 description 5
- 239000011572 manganese Substances 0.000 description 5
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 3
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000005056 compaction Methods 0.000 description 3
- 229910000398 iron phosphate Inorganic materials 0.000 description 3
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 description 3
- 238000011068 loading method Methods 0.000 description 3
- 229910052748 manganese Inorganic materials 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- 239000011574 phosphorus Substances 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000011164 primary particle Substances 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- 239000002351 wastewater Substances 0.000 description 3
- 238000004065 wastewater treatment Methods 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- QSNQXZYQEIKDPU-UHFFFAOYSA-N [Li].[Fe] Chemical compound [Li].[Fe] QSNQXZYQEIKDPU-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 150000001768 cations Chemical class 0.000 description 2
- 238000000975 co-precipitation Methods 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 230000001186 cumulative effect Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 239000002243 precursor Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 230000002860 competitive effect Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 229910001448 ferrous ion Inorganic materials 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000007709 nanocrystallization Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 239000007774 positive electrode material Substances 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/626—Metals
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- 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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- General Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention discloses a preparation method of low-cost lithium iron manganese phosphate. Carrying out synthetic reaction on a ferrous acetate solution, a high lithium manganate solution, lithium carbonate slurry and a lithium hydroxide solution in a synthetic kettle to obtain ferromanganese precipitate slurry; adding ammonium phosphate, a carbon source and a titanium vanadium precipitate into the ferromanganese precipitate slurry, adding water for slurrying, grinding, and grinding until the particle size is 0.2-0.3 mu m; spray drying the ground slurry to prepare a spherical particle material; putting the materials into a sintering furnace to be sintered under the protection of inert gas atmosphere to obtain a sintered material; and (3) performing jet milling, grading, screening, deferrization and packaging to obtain the carbon-coated lithium manganese iron phosphate material. The invention can prepare the lithium manganese iron phosphate of high-rate material, the processing cost in the whole process is lower than 1.5 ten thousand, and the cost of the whole lithium manganese iron phosphate is lower than that of the conventional process by more than 0.7 ten thousand yuan/ton.
Description
Technical Field
The invention relates to a preparation method of low-cost lithium iron manganese phosphate, belonging to the technical field of new energy materials.
Background
The field of power batteries is increasingly diversified, competition is continuously upgraded, and the power batteries are the leading ones in the future, are liked to be the heart power batteries of new energy automobiles, and are concerned with the temperature rise of the new energy automobile market. At present, due to the continuous change of technology and the factors of raw material price fluctuation and the like, the field of power batteries is undergoing new changes.
In the past, lithium manganese iron phosphate batteries (LFPs) and ternary lithium batteries (NCMs, the positive electrode material is three materials of nickel, cobalt and manganese) have been very competitive. At present, lithium manganese iron phosphate batteries are firmly positioned in domestic power batteries for many years, but are caught up with ternary lithium batteries in recent years, are surpassed by the ternary lithium batteries for the first time in 2018, and have a growing gap year by year. In the first half of 2020, the proportion of the ternary lithium battery in the market of power batteries at the peak period even exceeds seven per second.
However, the market became unrealistic. After nearly three years, the yield of the iron-manganese phosphate lithium battery is the first anti-super ternary lithium battery in 5 months in 2021. According to the prediction of the industry, the loading amount of the iron phosphate manganese lithium battery is expected to exceed that of a ternary lithium battery in 6 months, and the iron phosphate manganese lithium battery can be taken back to the champion Bao seat in the power battery market. The lithium iron power battery loading amount is expected to be equal to that of the ternary power battery in autumn all the year in 2021, and the lithium iron power battery loading amount is expected to be more comprehensive than that of the ternary power battery in 2022.
Why does lithium manganese iron phosphate battery realize a retrograde attack? Lithium manganese iron phosphate batteries are being pulled back by price advantage and technology for improving energy density and endurance. In 2021, in 5 months, the output of the power battery in China is 13.8GWH, and the output is increased by 165.8% on a par with the output. Wherein the 5-month yield of the lithium ferric manganese phosphate battery is 8.8GWH, which accounts for 63.6 percent of the total yield, the year-on-year yield is increased by 317.3 percent, and the ring ratio is increased by 41.6 percent; the yield of the ternary lithium battery is 5.0GWH, which accounts for 36.2 percent of the total yield, the homologous increase is 62.9 percent, and the ring ratio is reduced by 25.4 percent. Due to the rapid increase in the month 5 this year, the yield of the iron-manganese phosphate lithium battery is the first super ternary lithium battery since 2018, the cumulative yield in the month 1-5 this year is 29.9GWH, which accounts for 50.3% of the total yield; meanwhile, the cumulative yield of the ternary lithium battery is 29.5GWh, which accounts for 49.6% of the total yield. However, since the cost of lithium manganese iron phosphate is greatly affected by the increase in the price of lithium sources and the like, there is a strong demand for continuously reducing the processing cost of lithium manganese iron phosphate to maintain the price of lithium manganese iron phosphate.
At present, the conventional process is that iron phosphate is prepared by a liquid phase, and then is washed, dried and calcined to obtain anhydrous iron phosphate, wastewater containing ammonia nitrogen, sulfate radical and phosphate radical is generated at the same time, wastewater treatment is needed, and the obtained anhydrous iron phosphate is added with a lithium source, a carbon source and the like for grinding, drying and calcining. However, the process of the flow is long, and according to estimation, the total processing cost from the iron raw material to the final lithium manganese iron phosphate is estimated to be about 2 ten thousand yuan/ton, so that the processing cost is high.
Disclosure of Invention
Aiming at the existing problems, the invention provides a preparation method of low-cost lithium iron manganese phosphate, which obtains ferromanganese precipitate slurry through synthesis, the anions contained in the water-soluble organic acid are all decomposable anions without additionally introducing other impurity cations, then mixing phosphorus source, carbon source, additive, etc. and directly grinding and spray-drying, and can produce no waste water and need no waste water treatment, and the steps of washing, drying, calcining, dehydrating and the like of precursors are not needed, and the invention obtains the ferro-manganese coprecipitation by synthesis, then introduces titanium and vanadium by doping, can realize ion doping, improve the conductivity of the lithium ferric manganese phosphate and improve the capacity, can prepare the lithium ferric manganese phosphate of high-rate materials, and the processing cost in the whole process is lower than 1.5 ten thousand per ton, and the cost of the whole lithium manganese iron phosphate is lower than that of the conventional process by more than 0.7 ten thousand yuan per ton.
The invention solves the technical problems by the following technical means:
the invention relates to a preparation method of low-cost lithium iron manganese phosphate, which comprises the following steps:
(1) carrying out synthetic reaction on a ferrous acetate solution, a high lithium manganate solution, lithium carbonate slurry and a lithium hydroxide solution in a synthetic kettle to obtain ferromanganese precipitate slurry;
(2) adding ammonium phosphate, a carbon source and a titanium vanadium precipitate into the ferromanganese precipitate slurry, adding water for slurrying, grinding, and grinding until the particle size is 0.2-0.3 mu m;
(3) spray drying the ground slurry to prepare a spherical particle material;
(4) putting the materials into a sintering furnace, sintering for 5-7h at the temperature of 720 ℃ and 750 ℃ under the protection of inert gas atmosphere to obtain sintered materials;
(5) and (3) carrying out jet milling, grading, screening, deferrization and packaging on the sintered material to obtain the carbon-coated lithium ferric manganese phosphate material.
In the step (1), the concentrations of a ferrous acetate solution, a high lithium manganate solution, a lithium carbonate slurry and a lithium hydroxide solution are 1-2mol/L, the molar ratio of the ferrous acetate to the high lithium manganate to the lithium carbonate to the lithium hydroxide is 4:1:1.5-1.75:0.5-1, the ferrous acetate solution, the high lithium manganate solution, the lithium carbonate slurry and the lithium hydroxide solution are added into a reaction kettle together, the pH value in the process is maintained to be 10.2-10.7, the reaction temperature is 50-65 ℃, the stirring speed in the reaction process is 400-550r/min, the feeding time is 45-75min, and after the materials are added, the stirring reaction is continued for 30-45 min.
The ratio of the total moles of ferromanganese in the ferromanganese precipitate slurry to the moles of ammonium phosphate to the total moles of titanium and vanadium in the titanium and vanadium precipitate in the step (2) is 1:1.01-1.03:0.003-0.005, and the ratio of the moles of titanium and vanadium in the titanium and vanadium precipitate is 0.3-0.4: 0.6-0.7;
adding an ammonium metavanadate solution, a titanyl sulfate solution and ammonium bicarbonate into a reaction kettle together, maintaining the pH value of the process to be 5-6.5, the adding time to be 20-30min, the temperature of the feeding process to be 50-60 ℃, continuing to react for 15-20min, filtering and washing, calcining at the calcining temperature of 600-700 ℃ for 4-6h to obtain a titanium vanadium precipitate, and concentrating and crystallizing the filtered filtrate to obtain ammonium sulfate.
In the spray drying process in the step (3), a pressure type spray dryer is adopted, compressed air is used as a gas source, the ratio of the volume flow of the gas to the volume flow of the slurry is 50-100:1, the particle size of the fog drops is 15-25 mu m, hot air is used as a heat source, the temperature of a drying tower in the spray dryer is maintained at 130-plus-150 ℃, the pressure in the drying tower is 0.01-0.02MPa lower than the external atmospheric pressure, the volume in a dust collecting tower is 1.2-1.5 times of the volume of the drying tower, the mesh number of dust collecting cloth bags in the dust collecting tower is 400-plus-800 meshes, the area of the dust collecting cloth bags is 5-10 times of the sectional area of the dust collecting tower, the drying tower is communicated with the dust collecting tower, and the dust collecting tower is communicated with a draught fan.
In the calcining process in the step (4), an induced draft fan is adopted to continuously pump away the gas in the furnace, nitrogen is continuously supplied in the furnace, the purity of the nitrogen is more than or equal to 99.999%, the mass fraction of water in the nitrogen is less than 0.1ppm, the period of material feeding and discharging is 16-18h, two heat preservation sections are arranged in the material temperature rising stage, the heat preservation is respectively carried out for 1.5h at 200 ℃, 1h at 550 ℃, the temperature rising speed of the rest temperature rising section is 120-150 ℃/h, the humidity content of the heat preservation section is maintained to be less than 0.3%, and the furnace pressure in the whole sintering furnace is 20-40 Pa.
In the step (5), in the air flow crushing process, hot nitrogen with the temperature of 150-180 ℃ is adopted for crushing, the pressure of the nitrogen is 0.4-0.6MPa, the crushed nozzles are ceramic nozzles with the diameter of 4-6mm, the nozzles are arranged on the upper peripheral wall of the crushing cavity, 16 nozzles are arranged in total and then enter the grading cavity for grading, grading is carried out by adopting a grading wheel with the diameter of 18cm, 60 impellers are uniformly distributed on the grading wheel, the diameters of the impellers and the grading wheel are 5-10 degrees, the thickness of the grading wheel is 1-1.5cm, the rotating speed of the grading wheel is 100-500r/min, the grading cavity is communicated with an induced draft fan, the rotating speed of the induced draft fan is fixed, ceramic wafers are pasted in the crushing cavity and the grading cavity, and the grading wheel are both made of ceramic materials.
In the step (5), 100-mesh 200-mesh ultrasonic vibration sieves are adopted for screening, 2-level electromagnetic iron removal is carried out on iron removal by adopting an electromagnetic iron remover, and vacuum packaging is adopted for packaging.
Adding pure water into layered lithium manganate to prepare slurry, pouring the slurry into a sealed reaction kettle, introducing ozone at the temperature of 60-80 ℃ under the condition of stirring to enable the pressure in the reaction kettle to be 2-5 atmospheric pressures, reacting for 10-20 hours, then decompressing, cooling and filtering to obtain filtrate, namely the high lithium manganate solution, and returning the obtained filter residue to continue the reaction.
The carbon source is a mixture of sucrose and starch, and the carbon content of the finally obtained lithium manganese iron phosphate is 1.8-2.5%.
According to the invention, the ferrous acetate solution, the high lithium manganate solution, the lithium carbonate slurry and the lithium hydroxide solution are added into the reaction kettle together, the pH is controllable through the matching of lithium carbonate and lithium hydroxide, and the oxidation-reduction reaction is realized through the oxidability of high manganese acid radicals and the reducibility of ferrous ions, so that the ferro-manganese coprecipitation is obtained.
Then introducing a phosphorus source, a carbon source and a doping agent, performing sand grinding and spray drying to realize nanocrystallization and drying, and then performing calcination, wherein in the calcination step, the material is provided with two heat preservation sections at a temperature rise stage, the temperature is respectively kept at 200 ℃ for 1.5h and at 550 ℃ for 1h, the temperature rise speed of the remaining temperature rise section is 120-.
Meanwhile, the decomposition of anions such as acetate and the like can also generate a large amount of gas, so that the fusion growth among particles is further avoided.
The titanium vanadium precipitate is prepared by adding ammonium metavanadate solution, titanyl sulfate solution and ammonium bicarbonate into a reaction kettle, maintaining the pH value of the process at 5-6.5 for 20-30min, keeping the temperature of the feeding process at 50-60 ℃, continuing to react for 15-20min, filtering, washing, calcining at 600-700 ℃ for 4-6h, and obtaining the titanium vanadium precipitate. Thereby further improving the rate capability, and the 10C discharge of the material can be 140 mAh/g.
The invention has the beneficial effects that:
the ferromanganese precipitate slurry is obtained through synthesis, anions contained in the ferromanganese precipitate slurry are all decomposable anions without additionally introducing other impurity cations, then a phosphorus source, a carbon source, an additive and the like are mixed, grinding and spray drying are directly carried out, wastewater can not be generated, wastewater treatment is not required, and the steps of washing, drying, calcining, dehydrating and other precursors are not required.
Drawings
FIG. 1 is a SEM of example 1 of the invention.
Fig. 2 is a charge and discharge curve of example 1 of the present invention.
Fig. 3 is an XRD of example 1 of the present apparatus.
Detailed Description
The invention will be described in detail below with reference to the accompanying figure 1 and specific examples: the preparation method of low-cost lithium iron manganese phosphate of the embodiment is as follows:
(1) carrying out synthetic reaction on a ferrous acetate solution, a high lithium manganate solution, lithium carbonate slurry and a lithium hydroxide solution in a synthetic kettle to obtain ferromanganese precipitate slurry;
(2) adding ammonium phosphate, a carbon source and a titanium vanadium precipitate into the ferromanganese precipitate slurry, adding water for slurrying, grinding, and grinding until the particle size is 0.2-0.3 mu m;
(3) spray drying the ground slurry to prepare a spherical particle material;
(4) putting the materials into a sintering furnace, sintering for 5-7h at the temperature of 720 ℃ and 750 ℃ under the protection of inert gas atmosphere to obtain sintered materials;
(5) and (3) carrying out jet milling, grading, screening, deferrization and packaging on the sintered material to obtain the carbon-coated lithium ferric manganese phosphate material.
In the step (1), the concentrations of a ferrous acetate solution, a high lithium manganate solution, a lithium carbonate slurry and a lithium hydroxide solution are 1-2mol/L, the molar ratio of the ferrous acetate to the high lithium manganate to the lithium carbonate to the lithium hydroxide is 4:1:1.5-1.75:0.5-1, the ferrous acetate solution, the high lithium manganate solution, the lithium carbonate slurry and the lithium hydroxide solution are added into a reaction kettle together, the pH value in the process is maintained to be 10.2-10.7, the reaction temperature is 50-65 ℃, the stirring speed in the reaction process is 400-550r/min, the feeding time is 45-75min, and after the materials are added, the stirring reaction is continued for 30-45 min.
The ratio of the total moles of ferromanganese in the ferromanganese precipitate slurry to the moles of ammonium phosphate to the total moles of titanium and vanadium in the titanium and vanadium precipitate in the step (2) is 1:1.01-1.03:0.003-0.005, and the ratio of the moles of titanium and vanadium in the titanium and vanadium precipitate is 0.3-0.4: 0.6-0.7;
adding an ammonium metavanadate solution, a titanyl sulfate solution and ammonium bicarbonate into a reaction kettle together, maintaining the pH value of the process to be 5-6.5, the adding time to be 20-30min, the temperature of the feeding process to be 50-60 ℃, continuing to react for 15-20min, filtering and washing, calcining at the calcining temperature of 600-700 ℃ for 4-6h to obtain a titanium vanadium precipitate, and concentrating and crystallizing the filtered filtrate to obtain ammonium sulfate.
In the spray drying process in the step (3), a pressure type spray dryer is adopted, compressed air is used as a gas source, the ratio of the volume flow of the gas to the volume flow of the slurry is 50-100:1, the particle size of the fog drops is 15-25 mu m, hot air is used as a heat source, the temperature of a drying tower in the spray dryer is maintained at 130-plus-150 ℃, the pressure in the drying tower is 0.01-0.02MPa lower than the external atmospheric pressure, the volume in a dust collecting tower is 1.2-1.5 times of the volume of the drying tower, the mesh number of dust collecting cloth bags in the dust collecting tower is 400-plus-800 meshes, the area of the dust collecting cloth bags is 5-10 times of the sectional area of the dust collecting tower, the drying tower is communicated with the dust collecting tower, and the dust collecting tower is communicated with a draught fan.
In the calcining process in the step (4), an induced draft fan is adopted to continuously pump away the gas in the furnace, nitrogen is continuously supplied in the furnace, the purity of the nitrogen is more than or equal to 99.999%, the mass fraction of water in the nitrogen is less than 0.1ppm, the period of material feeding and discharging is 16-18h, two heat preservation sections are arranged in the material temperature rising stage, the heat preservation is respectively carried out for 1.5h at 200 ℃, 1h at 550 ℃, the temperature rising speed of the rest temperature rising section is 120-150 ℃/h, the humidity content of the heat preservation section is maintained to be less than 0.3%, and the furnace pressure in the whole sintering furnace is 20-40 Pa.
In the step (5), in the air flow crushing process, hot nitrogen with the temperature of 150-180 ℃ is adopted for crushing, the pressure of the nitrogen is 0.4-0.6MPa, the crushed nozzles are ceramic nozzles with the diameter of 4-6mm, the nozzles are arranged on the upper peripheral wall of the crushing cavity, 16 nozzles are arranged in total and then enter the grading cavity for grading, grading is carried out by adopting a grading wheel with the diameter of 18cm, 60 impellers are uniformly distributed on the grading wheel, the diameters of the impellers and the grading wheel are 5-10 degrees, the thickness of the grading wheel is 1-1.5cm, the rotating speed of the grading wheel is 100-500r/min, the grading cavity is communicated with an induced draft fan, the rotating speed of the induced draft fan is fixed, ceramic wafers are pasted in the crushing cavity and the grading cavity, and the grading wheel are both made of ceramic materials. In the step of the invention, the moisture in the material can be reduced through the arrangement of hot nitrogen, and meanwhile, the material is in contact with the ceramic in the whole process, so that the contact between the material and the metal is avoided, and the metal foreign matter is brought. The invention is provided with 16 nozzles, and the diameter of the nozzles is smaller, so that the gas flow rate and the impact force can be greatly improved, and the crushing efficiency is improved. And a grading wheel is adopted for grading, the diameter of the grading wheel is 18cm, 60 impellers are uniformly distributed on the grading wheel, the diameters of the impellers and the grading wheel are 5-10 degrees, the thickness of the grading wheel is 1-1.5cm, and the rotating speed of the grading wheel is 100 plus 500r/min, so that the particle size distribution of the lithium manganese iron phosphate can be more uniform, and the particle size of the lithium manganese iron phosphate can be regulated and controlled by adjusting the rotating speed of the grading wheel.
In the step (5), 100-mesh 200-mesh ultrasonic vibration sieves are adopted for screening, 2-level electromagnetic iron removal is carried out on iron removal by adopting an electromagnetic iron remover, and vacuum packaging is adopted for packaging.
Adding pure water into layered lithium manganate to prepare slurry, pouring the slurry into a sealed reaction kettle, introducing ozone at the temperature of 60-80 ℃ under the condition of stirring to enable the pressure in the reaction kettle to be 2-5 atmospheric pressures, reacting for 10-20 hours, then decompressing, cooling and filtering to obtain filtrate, namely the high lithium manganate solution, and returning the obtained filter residue to continue the reaction.
The carbon source is a mixture of sucrose and starch, and the carbon content of the finally obtained lithium manganese iron phosphate is 1.8-2.5%.
Example 1
A preparation method of low-cost lithium iron manganese phosphate comprises the following steps:
(1) carrying out synthetic reaction on a ferrous acetate solution, a high lithium manganate solution, lithium carbonate slurry and a lithium hydroxide solution in a synthetic kettle to obtain ferromanganese precipitate slurry;
(2) adding ammonium phosphate, a carbon source and a titanium vanadium precipitate into the ferromanganese precipitate slurry, adding water for slurrying, grinding, and grinding until the particle size is 0.21 mu m;
(3) spray drying the ground slurry to prepare a spherical particle material;
(4) putting the materials into a sintering furnace, and sintering for 7 hours at 720 ℃ under the protection of inert gas atmosphere to obtain a sintered material;
(5) and (3) carrying out jet milling, grading, screening, deferrization and packaging on the sintered material to obtain the carbon-coated lithium ferric manganese phosphate material.
In the step (1), the concentrations of the ferrous acetate solution, the high lithium manganate solution, the lithium carbonate slurry and the lithium hydroxide solution are 1.5mol/L, the molar ratio of the ferrous acetate solution to the high lithium manganate, the lithium carbonate and the lithium hydroxide is 4:1:1.5:1, the ferrous acetate solution, the high lithium manganate solution, the lithium carbonate slurry and the lithium hydroxide solution are added into a reaction kettle together, the pH value in the process is maintained to be 10.7, the reaction temperature is 55 ℃, the stirring speed in the reaction process is 550r/min, the feeding time is 75min, and after the materials are added, the stirring reaction is continued for 45 min.
The ratio of the total moles of ferromanganese in the ferromanganese precipitate slurry to the moles of ammonium phosphate to the total moles of titanium and vanadium in the titanium and vanadium precipitate in the step (2) is 1:1.01:0.005, and the ratio of the moles of titanium and vanadium in the titanium and vanadium precipitate is 0.3: 0.7;
adding an ammonium metavanadate solution, a titanyl sulfate solution and ammonium bicarbonate into a reaction kettle together, maintaining the pH value of the process to be 6.5, adding for 30min, controlling the temperature of the feeding process to be 60 ℃, continuing to react for 20min, filtering, washing, calcining at 700 ℃ for 6h to obtain a titanium vanadium precipitate, and concentrating and crystallizing the filtered filtrate to obtain ammonium sulfate.
In the spray drying process in the step (3), a pressure type spray dryer is adopted, compressed air is used as a gas source, the ratio of the volume flow of gas to the volume flow of slurry is 100:1, the particle size of fog drops is 15 microns, hot air is used as a heat source, the temperature of a drying tower in the spray dryer is maintained at 130 ℃, the pressure in the drying tower is lower than the external atmospheric pressure by 0.02MPa, the volume in a dust collecting tower is 1.5 times of the volume of the drying tower, the mesh number of dust collecting cloth bags in the dust collecting tower is 800 meshes, the area of the dust collecting cloth bags is 9 times of the sectional area of the dust collecting tower, the drying tower is communicated with the dust collecting tower, and the dust collecting tower is communicated with a draught fan.
In the calcining process in the step (4), an induced draft fan is adopted to continuously pump away gas in the furnace, nitrogen is continuously supplied in the furnace, the purity of the nitrogen is more than or equal to 99.999%, the mass fraction of water in the nitrogen is less than 0.1ppm, the period of material feeding and discharging is 18h, two heat preservation sections are arranged in the material temperature rising stage, the heat preservation is respectively carried out for 1.5h at 200 ℃ and 1h at 550 ℃, the temperature rising speed of the rest temperature rising section is 145 ℃/h, the humidity content of the heat preservation section is kept to be less than 0.3%, and the furnace pressure in the whole sintering furnace is 30 Pa.
In the step (5), the hot nitrogen with the temperature of 155 ℃ is adopted for crushing in the air flow crushing process, the pressure of the nitrogen is 0.5MPa, the ceramic nozzles with the diameter of 5mm are adopted for the crushed nozzles, the nozzles are arranged on the peripheral wall of the upper part of the crushing cavity, 16 nozzles are arranged in total and then enter the grading cavity for grading, the grading is carried out by adopting a grading wheel for grading, the diameter of the grading wheel is 18cm, 60 impellers are uniformly distributed on the grading wheel, the diameters of the impellers and the grading wheel are 5 degrees, the thickness of the grading wheel is 1.5cm, the rotating speed of the grading wheel is 100r/min, the grading cavity is communicated with an induced draft fan, the rotating speed of the induced draft fan is fixed, ceramic plates are pasted in the crushing cavity and the grading cavity, and the impeller and the grading wheel are both made of ceramic materials.
In the step (5), a 100-mesh ultrasonic vibration sieve is adopted for screening, 2-level electromagnetic iron removal is carried out on iron removal by adopting an electromagnetic iron remover, and vacuum packaging is adopted for packaging.
The preparation process of the lithium permanganate comprises the steps of adding pure water into layered lithium manganate to pulp, then pouring the pulp into a sealed reaction kettle, then introducing ozone at the temperature of 60 ℃ under the condition of stirring to enable the pressure in the reaction kettle to be 3 atmospheric pressures, reacting for 12 hours, then decompressing, cooling and filtering to obtain filtrate, namely the lithium permanganate solution, and returning the obtained filter residue to continue the reaction.
The carbon source is a mixture of sucrose and starch, and the carbon content of the finally obtained lithium manganese iron phosphate is 2.1%.
The detection data of the lithium manganese iron phosphate finally prepared are as follows:
| index (I) | Li | Fe | Mn | P |
| Data of | 4.45％ | 27.38％ | 6.84％ | 19.62％ |
| Ti | V | C | BET | Tap density |
| 367ppm | 855ppm | 2.1％ | 17.57m2/g | 0.92g/mL |
| Density of compaction | 0.1C charge capacity | 0.1C discharge capacity | First discharge efficiency | 5C charging capacity |
| 2.1g/mL | 161.7mAh/g | 158.5mAh/g | 98％ | 147mAh/g |
| 10C charging capacity | Internal resistance of powder | Magnetic substance | Primary particle diameter | D10 |
| 141mAh/g | 7.2Ω.cm | 0.08ppm | 30nm | 1.1μm |
| D50 | D90 | Ca | Mg | pH |
| 1.8μm | 3.2μm | 21ppm | 12ppm | 8.9 |
Remarking: the compaction density was measured at a pressure of 5T and the internal resistance of the powder was measured at a pressure of 10 MPa.
As shown in fig. 1, the SEM of lithium manganese iron phosphate of the present example shows that the primary particle size is very small and relatively uniform. Fig. 2 is a charge-discharge curve of the present embodiment, which is a charge-discharge curve of 0.1C, 1C, 5C and 10C of the lithium manganese iron phosphate material from right to left, respectively, and the rate capability is very excellent. Fig. 3 shows XRD of this example, which is XRD phase of lithium manganese iron phosphate, and the crystallinity is good and the phase is pure.
Example 2
A preparation method of low-cost lithium iron manganese phosphate comprises the following steps:
(1) carrying out synthetic reaction on a ferrous acetate solution, a high lithium manganate solution, lithium carbonate slurry and a lithium hydroxide solution in a synthetic kettle to obtain ferromanganese precipitate slurry;
(2) adding ammonium phosphate, a carbon source and a titanium vanadium precipitate into the ferromanganese precipitate slurry, adding water for slurrying, grinding, and grinding until the particle size is 0.3 mu m;
(3) spray drying the ground slurry to prepare a spherical particle material;
(4) putting the materials into a sintering furnace, and sintering for 7 hours at 750 ℃ under the protection of inert gas atmosphere to obtain a sintered material;
(5) and (3) carrying out jet milling, grading, screening, deferrization and packaging on the sintered material to obtain the carbon-coated lithium ferric manganese phosphate material.
In the step (1), the concentrations of a ferrous acetate solution, a high lithium manganate solution, a lithium carbonate slurry and a lithium hydroxide solution are 2mol/L, the molar ratio of the ferrous acetate to the high lithium manganate to the lithium carbonate to the lithium hydroxide is 4:1:1.75:0.5, the ferrous acetate solution, the high lithium manganate solution, the lithium carbonate slurry and the lithium hydroxide solution are added into a reaction kettle together, the pH value during the process is maintained at 10.2, the reaction temperature is 65 ℃, the stirring speed during the reaction process is 550r/min, the feeding time is 75min, and after the materials are added, the stirring reaction is continued for 45 min.
The ratio of the total moles of ferromanganese in the ferromanganese precipitate slurry to the moles of ammonium phosphate to the total moles of titanium and vanadium in the titanium and vanadium precipitate in the step (2) is 1:1.03:0.005, and the ratio of the moles of titanium and vanadium in the titanium and vanadium precipitate is 0.4: 0.6;
adding an ammonium metavanadate solution, a titanyl sulfate solution and ammonium bicarbonate into a reaction kettle together, maintaining the pH value of the process to be 6.5, adding for 30min, controlling the temperature of the feeding process to be 60 ℃, continuing to react for 20min, filtering, washing, calcining at 700 ℃ for 6h to obtain a titanium vanadium precipitate, and concentrating and crystallizing the filtered filtrate to obtain ammonium sulfate.
In the spray drying process in the step (3), a pressure type spray dryer is adopted, compressed air is used as a gas source, the ratio of the volume flow of gas to the volume flow of slurry is 100:1, the particle size of fog drops is 15 microns, hot air is used as a heat source, the temperature of a drying tower in the spray dryer is maintained at 150 ℃, the pressure in the drying tower is lower than the external atmospheric pressure by 0.02MPa, the volume in a dust collecting tower is 1.5 times of the volume of the drying tower, the mesh number of dust collecting cloth bags in the dust collecting tower is 800 meshes, the area of the dust collecting cloth bags is 10 times of the sectional area of the dust collecting tower, the drying tower is communicated with the dust collecting tower, and the dust collecting tower is communicated with a draught fan.
In the calcining process in the step (4), an induced draft fan is adopted to continuously pump away gas in the furnace, nitrogen is continuously supplied in the furnace, the purity of the nitrogen is more than or equal to 99.999%, the mass fraction of water in the nitrogen is less than 0.1ppm, the period of material feeding and discharging is 18h, two heat preservation sections are arranged in the material temperature rising stage, the heat preservation is respectively carried out for 1.5h at 200 ℃ and 1h at 550 ℃, the temperature rising speed of the rest temperature rising section is 150 ℃/h, the humidity content of the heat preservation section is kept to be less than 0.3%, and the furnace pressure in the whole sintering furnace is 40 Pa.
In the step (5), the hot nitrogen with the temperature of 180 ℃ is adopted for crushing in the air flow crushing process, the pressure of the nitrogen is 0.6MPa, the ceramic nozzles with the diameter of 6mm are adopted for the crushed nozzles, the nozzles are arranged on the peripheral wall of the upper part of the crushing cavity, 16 nozzles are arranged in total and then enter the grading cavity for grading, the grading is carried out by adopting a grading wheel for grading, the diameter of the grading wheel is 18cm, 60 impellers are uniformly distributed on the grading wheel, the diameters of the impellers and the grading wheel are 10 degrees, the thickness of the grading wheel is 1.5cm, the rotating speed of the grading wheel is 500r/min, the grading cavity is communicated with an induced draft fan, the rotating speed of the induced draft fan is fixed, ceramic plates are pasted in the crushing cavity and the grading cavity, and the impeller and the grading wheel are both made of ceramic materials.
In the step (5), a 100-mesh ultrasonic vibration sieve is adopted for screening, 2-level electromagnetic iron removal is carried out on iron removal by adopting an electromagnetic iron remover, and vacuum packaging is adopted for packaging.
The preparation process of the lithium permanganate comprises the steps of adding pure water into layered lithium manganate to pulp, then pouring the pulp into a sealed reaction kettle, then introducing ozone at the temperature of 70 ℃ under the condition of stirring to enable the pressure in the reaction kettle to be 3 atmospheric pressures, reacting for 15 hours, then decompressing, cooling and filtering to obtain filtrate, namely the lithium permanganate solution, and returning the obtained filter residue to continue the reaction.
The carbon source is a mixture of sucrose and starch, and the carbon content of the finally obtained lithium manganese iron phosphate is 2.0%.
The detection data of the lithium manganese iron phosphate finally prepared are as follows:
example 3
A preparation method of low-cost lithium iron manganese phosphate comprises the following steps:
(1) carrying out synthetic reaction on a ferrous acetate solution, a high lithium manganate solution, lithium carbonate slurry and a lithium hydroxide solution in a synthetic kettle to obtain ferromanganese precipitate slurry;
(2) adding ammonium phosphate, a carbon source and a titanium vanadium precipitate into the ferromanganese precipitate slurry, adding water for slurrying, grinding, and grinding until the particle size is 0.25 mu m;
(3) spray drying the ground slurry to prepare a spherical particle material;
(4) putting the materials into a sintering furnace, and sintering for 6h at 740 ℃ under the protection of inert gas atmosphere to obtain a sintered material;
(5) and (3) carrying out jet milling, grading, screening, deferrization and packaging on the sintered material to obtain the carbon-coated lithium ferric manganese phosphate material.
In the step (1), the concentrations of a ferrous acetate solution, a high lithium manganate solution, a lithium carbonate slurry and a lithium hydroxide solution are 1.5mol/L, the molar ratio of the ferrous acetate to the high lithium manganate to the lithium carbonate to the lithium hydroxide is 4:1:1.6:0.8, the ferrous acetate solution, the high lithium manganate solution, the lithium carbonate slurry and the lithium hydroxide solution are added into a reaction kettle together, the pH value in the process is maintained to be 10.55, the reaction temperature is 60 ℃, the stirring speed in the reaction process is 500r/min, the feeding time is 65min, and after the materials are added, the stirring reaction is continued for 40 min.
The ratio of the total moles of manganese and iron in the manganese-iron precipitate slurry to the moles of ammonium phosphate to the total moles of titanium and vanadium in the titanium-vanadium precipitate in the step (2) is 1:1.02:0.004, and the ratio of the moles of titanium and vanadium in the titanium-vanadium precipitate is 0.3: 0.7;
adding an ammonium metavanadate solution, a titanyl sulfate solution and ammonium bicarbonate into a reaction kettle together, maintaining the pH value of the process to be 5.5, adding for 25min, keeping the temperature of the feeding process to be 55 ℃, continuing to react for 15min, filtering, washing, calcining at the temperature of 650 ℃ for 5h to obtain a titanium vanadium precipitate, and concentrating and crystallizing the filtered filtrate to obtain ammonium sulfate.
In the spray drying process in the step (3), a pressure type spray dryer is adopted, compressed air is used as a gas source, the ratio of the volume flow of gas to the volume flow of slurry is 80:1, the particle size of fog drops is 20 microns, hot air is used as a heat source, the temperature of a drying tower in the spray dryer is maintained at 140 ℃, the pressure in the drying tower is lower than the external atmospheric pressure by 0.015MPa, the volume in a dust collecting tower is 1.4 times of the volume of the drying tower, the mesh number of dust collecting cloth bags in the dust collecting tower is 600 meshes, the area of the dust collecting cloth bags is 7 times of the sectional area of the dust collecting tower, the drying tower is communicated with the dust collecting tower, and the dust collecting tower is communicated with a draught fan.
In the calcining process in the step (4), an induced draft fan is adopted to continuously pump away gas in the furnace, nitrogen is continuously supplied in the furnace, the purity of the nitrogen is more than or equal to 99.999%, the mass fraction of water in the nitrogen is less than 0.1ppm, the period of material feeding and discharging is 18h, two heat preservation sections are arranged in the material temperature rising stage, the heat preservation is respectively carried out for 1.5h at 200 ℃ and 1h at 550 ℃, the temperature rising speed of the rest temperature rising section is 140 ℃/h, the humidity content of the heat preservation section is kept to be less than 0.3%, and the furnace pressure in the whole sintering furnace is 30 Pa.
In the step (5), the hot nitrogen with the temperature of 160 ℃ is adopted for crushing in the air flow crushing process, the pressure of the nitrogen is 0.5MPa, the ceramic nozzles with the diameter of 5mm are adopted for the crushed nozzles, the nozzles are arranged on the peripheral wall of the upper part of the crushing cavity, 16 nozzles are arranged in total and then enter the grading cavity for grading, the grading is carried out by adopting a grading wheel for grading, the diameter of the grading wheel is 18cm, 60 impellers are uniformly distributed on the grading wheel, the diameters of the impellers and the grading wheel are 10 degrees, the thickness of the grading wheel is 1.2cm, the rotating speed of the grading wheel is 300r/min, the grading cavity is communicated with an induced draft fan, the rotating speed of the induced draft fan is fixed, ceramic plates are pasted in the crushing cavity and the grading cavity, and the impeller and the grading wheel are both made of ceramic materials.
In the step (5), a 100-mesh ultrasonic vibration sieve is adopted for screening, 2-level electromagnetic iron removal is carried out on iron removal by adopting an electromagnetic iron remover, and vacuum packaging is adopted for packaging.
The preparation process of the lithium permanganate comprises the steps of adding pure water into layered lithium manganate to pulp, then pouring the pulp into a sealed reaction kettle, then introducing ozone at the temperature of 70 ℃ under the condition of stirring to enable the pressure in the reaction kettle to be 3 atmospheric pressures, reacting for 15 hours, then decompressing, cooling and filtering to obtain filtrate, namely the lithium permanganate solution, and returning the obtained filter residue to continue the reaction.
The carbon source is a mixture of sucrose and starch, and the carbon content of the finally obtained lithium manganese iron phosphate is 2.5%.
| Index (I) | Li | Fe | Mn | P |
| Data of | 4.41％ | 27.21％ | 6.79％ | 19.51％ |
| Ti | V | C | BET | Tap density |
| 321ppm | 812ppm | 2.5％ | 17.99m2/g | 0.86g/mL |
| Density of compaction | 0.1C charge capacity | 0.1C discharge capacity | First discharge efficiency | 5C charging capacity |
| 2.0g/mL | 161.6mAh/g | 159.2mAh/g | 98.5％ | 146mAh/g |
| 10C charging capacity | Internal resistance of powder | Magnetic substance | Primary particle diameter | D10 |
| 141mAh/g | 5.3Ω.cm | 0.03ppm | 31nm | 1.0μm |
| D50 | D90 | Ca | Mg | pH |
| 1.4μm | 3.1μm | 20ppm | 10ppm | 8.6 |
Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.
Claims (9)
1. A preparation method of low-cost lithium iron manganese phosphate is characterized by comprising the following steps: comprises the following steps:
(1) carrying out synthetic reaction on a ferrous acetate solution, a high lithium manganate solution, lithium carbonate slurry and a lithium hydroxide solution in a synthetic kettle to obtain ferromanganese precipitate slurry;
(2) adding ammonium phosphate, a carbon source and a titanium vanadium precipitate into the ferromanganese precipitate slurry, adding water for slurrying, grinding, and grinding until the particle size is 0.2-0.3 mu m;
(3) spray drying the ground slurry to prepare a spherical particle material;
(4) putting the materials into a sintering furnace, sintering for 5-7h at the temperature of 720 ℃ and 750 ℃ under the protection of inert gas atmosphere to obtain sintered materials;
(5) and (3) carrying out jet milling, grading, screening, deferrization and packaging on the sintered material to obtain the carbon-coated lithium ferric manganese phosphate material.
2. The method for preparing low-cost lithium iron manganese phosphate according to claim 1, wherein the method comprises the following steps: in the step (1), the concentrations of a ferrous acetate solution, a high lithium manganate solution, a lithium carbonate slurry and a lithium hydroxide solution are 1-2mol/L, the molar ratio of the ferrous acetate to the high lithium manganate to the lithium carbonate to the lithium hydroxide is 4:1:1.5-1.75:0.5-1, the ferrous acetate solution, the high lithium manganate solution, the lithium carbonate slurry and the lithium hydroxide solution are added into a reaction kettle together, the pH value in the process is maintained to be 10.2-10.7, the reaction temperature is 50-65 ℃, the stirring speed in the reaction process is 400-550r/min, the feeding time is 45-75min, and after the materials are added, the stirring reaction is continued for 30-45 min.
3. The method for preparing low-cost lithium iron manganese phosphate according to claim 1, wherein the method comprises the following steps: the ratio of the total moles of ferromanganese in the ferromanganese precipitate slurry to the moles of ammonium phosphate to the total moles of titanium and vanadium in the titanium and vanadium precipitate in the step (2) is 1:1.01-1.03:0.003-0.005, and the ratio of the moles of titanium and vanadium in the titanium and vanadium precipitate is 0.3-0.4: 0.6-0.7;
adding an ammonium metavanadate solution, a titanyl sulfate solution and ammonium bicarbonate into a reaction kettle together, maintaining the pH value of the process to be 5-6.5, the adding time to be 20-30min, the temperature of the feeding process to be 50-60 ℃, continuing to react for 15-20min, filtering and washing, calcining at the calcining temperature of 600-700 ℃ for 4-6h to obtain a titanium vanadium precipitate, and concentrating and crystallizing the filtered filtrate to obtain ammonium sulfate.
4. The method for preparing low-cost lithium iron manganese phosphate according to claim 1, wherein the method comprises the following steps: in the spray drying process in the step (3), a pressure type spray dryer is adopted, compressed air is used as a gas source, the ratio of the volume flow of the gas to the volume flow of the slurry is 50-100:1, the particle size of the fog drops is 15-25 mu m, hot air is used as a heat source, the temperature of a drying tower in the spray dryer is maintained at 130-plus-150 ℃, the pressure in the drying tower is 0.01-0.02MPa lower than the external atmospheric pressure, the volume in a dust collecting tower is 1.2-1.5 times of the volume of the drying tower, the mesh number of dust collecting cloth bags in the dust collecting tower is 400-plus-800 meshes, the area of the dust collecting cloth bags is 5-10 times of the sectional area of the dust collecting tower, the drying tower is communicated with the dust collecting tower, and the dust collecting tower is communicated with a draught fan.
5. The method for preparing low-cost lithium iron manganese phosphate according to claim 1, wherein the method comprises the following steps: in the calcining process in the step (4), an induced draft fan is adopted to continuously pump away the gas in the furnace, nitrogen is continuously supplied in the furnace, the purity of the nitrogen is more than or equal to 99.999%, the mass fraction of water in the nitrogen is less than 0.1ppm, the period of material feeding and discharging is 16-18h, two heat preservation sections are arranged in the material temperature rising stage, the heat preservation is respectively carried out for 1.5h at 200 ℃, 1h at 550 ℃, the temperature rising speed of the rest temperature rising section is 120-150 ℃/h, the humidity content of the heat preservation section is maintained to be less than 0.3%, and the furnace pressure in the whole sintering furnace is 20-40 Pa.
6. The method for preparing low-cost lithium iron manganese phosphate according to claim 1, wherein the method comprises the following steps: in the step (5), in the air flow crushing process, hot nitrogen with the temperature of 150-180 ℃ is adopted for crushing, the pressure of the nitrogen is 0.4-0.6MPa, the crushed nozzles are ceramic nozzles with the diameter of 4-6mm, the nozzles are arranged on the upper peripheral wall of the crushing cavity, 16 nozzles are arranged in total and then enter the grading cavity for grading, grading is carried out by adopting a grading wheel with the diameter of 18cm, 60 impellers are uniformly distributed on the grading wheel, the diameters of the impellers and the grading wheel are 5-10 degrees, the thickness of the grading wheel is 1-1.5cm, the rotating speed of the grading wheel is 100-500r/min, the grading cavity is communicated with an induced draft fan, the rotating speed of the induced draft fan is fixed, ceramic wafers are pasted in the crushing cavity and the grading cavity, and the grading wheel are both made of ceramic materials.
7. The method for preparing low-cost lithium iron manganese phosphate according to claim 1, wherein the method comprises the following steps: in the step (5), 100-mesh 200-mesh ultrasonic vibration sieves are adopted for screening, 2-level electromagnetic iron removal is carried out on iron removal by adopting an electromagnetic iron remover, and vacuum packaging is adopted for packaging.
8. The method for preparing low-cost lithium iron manganese phosphate according to claim 1, wherein the method comprises the following steps: adding pure water into layered lithium manganate to prepare slurry, pouring the slurry into a sealed reaction kettle, introducing ozone at the temperature of 60-80 ℃ under the condition of stirring to enable the pressure in the reaction kettle to be 2-5 atmospheric pressures, reacting for 10-20 hours, then decompressing, cooling and filtering to obtain filtrate, namely the high lithium manganate solution, and returning the obtained filter residue to continue the reaction.
9. The method for preparing low-cost lithium iron manganese phosphate according to claim 1, wherein the method comprises the following steps: the carbon source is a mixture of sucrose and starch, and the carbon content of the finally obtained lithium manganese iron phosphate is 1.8-2.5%.
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