CN112225190A - Preparation method of battery-grade anhydrous iron phosphate - Google Patents
Preparation method of battery-grade anhydrous iron phosphate Download PDFInfo
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- CN112225190A CN112225190A CN202011137749.2A CN202011137749A CN112225190A CN 112225190 A CN112225190 A CN 112225190A CN 202011137749 A CN202011137749 A CN 202011137749A CN 112225190 A CN112225190 A CN 112225190A
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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 86
- 229910000398 iron phosphate Inorganic materials 0.000 title claims abstract description 38
- 238000002360 preparation method Methods 0.000 title claims abstract description 12
- 239000000463 material Substances 0.000 claims abstract description 95
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims abstract description 92
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims abstract description 70
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 65
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 64
- 229910000399 iron(III) phosphate Inorganic materials 0.000 claims abstract description 50
- 238000003756 stirring Methods 0.000 claims abstract description 49
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims abstract description 46
- 239000005955 Ferric phosphate Substances 0.000 claims abstract description 45
- 229940032958 ferric phosphate Drugs 0.000 claims abstract description 45
- 238000005406 washing Methods 0.000 claims abstract description 43
- 239000000706 filtrate Substances 0.000 claims abstract description 35
- 238000001914 filtration Methods 0.000 claims abstract description 32
- 229910052742 iron Inorganic materials 0.000 claims abstract description 31
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 28
- 239000010959 steel Substances 0.000 claims abstract description 28
- 238000000034 method Methods 0.000 claims abstract description 22
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims abstract description 21
- 239000004202 carbamide Substances 0.000 claims abstract description 21
- 238000007599 discharging Methods 0.000 claims abstract description 20
- 238000001354 calcination Methods 0.000 claims abstract description 14
- 238000001035 drying Methods 0.000 claims abstract description 14
- 238000012216 screening Methods 0.000 claims abstract description 14
- 238000006243 chemical reaction Methods 0.000 claims abstract description 12
- 238000010438 heat treatment Methods 0.000 claims abstract description 7
- 238000009461 vacuum packaging Methods 0.000 claims abstract description 7
- 239000012452 mother liquor Substances 0.000 claims description 14
- 239000007788 liquid Substances 0.000 claims description 13
- 238000005303 weighing Methods 0.000 claims description 12
- 239000004254 Ammonium phosphate Substances 0.000 claims description 10
- 229910000148 ammonium phosphate Inorganic materials 0.000 claims description 10
- 235000019289 ammonium phosphates Nutrition 0.000 claims description 10
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 claims description 10
- 238000001704 evaporation Methods 0.000 claims description 9
- 230000008020 evaporation Effects 0.000 claims description 9
- 238000005554 pickling Methods 0.000 claims description 8
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 7
- 238000001816 cooling Methods 0.000 claims description 6
- 230000000694 effects Effects 0.000 claims description 6
- 229910021645 metal ion Inorganic materials 0.000 claims description 6
- 238000009826 distribution Methods 0.000 abstract description 8
- 239000002245 particle Substances 0.000 abstract description 8
- 238000002156 mixing Methods 0.000 abstract description 6
- 239000010865 sewage Substances 0.000 abstract description 5
- 238000010902 jet-milling Methods 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 36
- 229910019142 PO4 Inorganic materials 0.000 description 6
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- 150000001450 anions Chemical class 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 3
- -1 ammonium ions Chemical class 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 239000003337 fertilizer Substances 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
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 150000004683 dihydrates Chemical class 0.000 description 2
- YPJKMVATUPSWOH-UHFFFAOYSA-N nitrooxidanyl Chemical compound [O][N+]([O-])=O YPJKMVATUPSWOH-UHFFFAOYSA-N 0.000 description 2
- 238000004537 pulping Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical group [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- DPTATFGPDCLUTF-UHFFFAOYSA-N phosphanylidyneiron Chemical compound [Fe]#P DPTATFGPDCLUTF-UHFFFAOYSA-N 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 229910001414 potassium ion Inorganic materials 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 239000001488 sodium phosphate Substances 0.000 description 1
- 229910000162 sodium phosphate Inorganic materials 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
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Classifications
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/26—Phosphates
- C01B25/37—Phosphates of heavy metals
- C01B25/375—Phosphates of heavy metals of iron
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/26—Phosphates
- C01B25/28—Ammonium phosphates
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05B—PHOSPHATIC FERTILISERS
- C05B11/00—Fertilisers produced by wet-treating or leaching raw materials either with acids in such amounts and concentrations as to yield solutions followed by neutralisation, or with alkaline lyes
- C05B11/04—Fertilisers produced by wet-treating or leaching raw materials either with acids in such amounts and concentrations as to yield solutions followed by neutralisation, or with alkaline lyes using mineral acid
- C05B11/10—Fertilisers produced by wet-treating or leaching raw materials either with acids in such amounts and concentrations as to yield solutions followed by neutralisation, or with alkaline lyes using mineral acid using orthophosphoric acid
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/51—Particles with a specific particle size distribution
- C01P2004/52—Particles with a specific particle size distribution highly monodisperse size distribution
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/11—Powder tap density
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/12—Surface area
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
- C01P2006/82—Compositional purity water content
Abstract
The invention discloses a preparation method of battery-grade anhydrous iron phosphate. Mixing acid-washed iron oxide red of a steel plant with a phosphoric acid solution, stirring for reaction, and filtering to obtain a filtrate and filter residues; adding urea into the obtained filtrate, then continuously heating to the temperature of 95-100 ℃, stirring for reaction until the end point pH is 2.1-2.2, then stopping stirring, pouring out the materials, and filtering to obtain a first filtrate and a first filter residue; adding hot pure water into the first filter residue, slurrying and washing, and discharging the washing material; carrying out microwave drying on the washed materials by a microwave dryer, and then screening and electromagnetically removing iron to obtain battery-grade ferric phosphate dihydrate; adding battery-grade ferric phosphate dihydrate into a rotary furnace for calcining, then discharging, screening and deironing the discharged material after jet milling, and carrying out vacuum packaging to obtain the battery-grade anhydrous ferric phosphate. The method has the advantages of short flow, low cost, simple operation and less sewage generation, and can obtain the battery-grade iron phosphate with narrow particle size distribution, good consistency and high purity.
Description
Technical Field
The invention relates to a preparation method of battery-grade anhydrous iron phosphate, belonging to the technical field of lithium batteries.
Background
Commercial iron phosphate, also known as ferric orthophosphate. The iron in the ferric phosphate is ferric iron, takes dihydrate as majority, and has a molecular formula of FePO4It is white and off-white monoclinic crystal powder. Is salt formed by the action of ferric salt solution and sodium phosphate, wherein the iron is in positive trivalent state. The method is mainly used for manufacturing lithium iron phosphate battery materials, catalysts, ceramics and the like. The color of the high-purity ferric phosphate dihydrate is white powder, the color gradually turns yellow along with the loss of crystal water, a pure anhydrous substance is yellow white powder, and the appearance of the high-purity ferric phosphate dihydrate is off-white or dark grey white when phosphorus (P) exceeds the standard; such as ironWhen overtime, the color is dark yellow. The phosphorus-iron ratio is the most critical index for measuring the quality of the iron phosphate and is also the most critical factor for determining the quality of the lithium iron phosphate. If a large amount of ferrous iron, sodium ions, potassium ions, sulfate ions and ammonium ions exist in the iron phosphate, the dihydrate of the iron phosphate is dark black or grey white.
With the development of lithium iron phosphate batteries, lithium iron phosphate is increasingly used in passenger cars, special cars, low-speed electric cars and the like due to high cyclicity, high safety, low price and the like. The annual demand for lithium iron phosphate is approximately 7-9 million tons, and the amount of battery grade iron phosphate required is also approximately 6.5-8.5 million tons per year.
The current production process of battery-grade iron phosphate is generally obtained by mixing and reacting an iron source and phosphate, but has the following problems:
1. and (3) precipitation reaction, wherein the particle size distribution of the iron phosphate is wider due to fluctuation of reaction conditions in the feeding process and the reaction process.
2. Since the iron source introduces anions, anions such as chloride, sulfate, nitrate, etc. are entrained in the iron phosphate, resulting in high anion content.
3. A large amount of sewage is generated, and the sewage treatment process is long and the cost is high.
Disclosure of Invention
In view of the above, the invention provides a preparation method of battery-grade anhydrous iron phosphate, which has the advantages of short flow, low cost, simple operation, and less sewage generation amount, and can obtain battery-grade iron phosphate with narrow particle size distribution, good consistency and high purity.
The invention solves the technical problems by the following technical means:
the invention relates to a preparation method of battery-grade anhydrous iron phosphate, which comprises the steps of mixing acid-washed iron oxide red of a steel plant with a phosphoric acid solution, stirring and reacting for 1-2 hours at the temperature of 95-100 ℃, and then filtering to obtain filtrate and filter residue;
adding urea into the obtained filtrate, then continuously heating to the temperature of 95-100 ℃, stirring for reacting for 2-3h until the end point pH is 2.1-2.2, then stopping stirring, pouring out the materials and filtering to obtain a first filtrate and a first filter residue;
adding hot pure water into the first filter residue, stirring and dispersing for primary slurrying, filtering the obtained primary slurried material, washing for 20-25min, discharging the material, adding hot pure water for secondary slurrying, filtering the obtained secondary slurried material, washing for 10-15min, and discharging the washed material;
carrying out microwave drying on the washed materials by a microwave dryer, and then screening and electromagnetically removing iron to obtain battery-grade ferric phosphate dihydrate;
adding battery-grade ferric phosphate dihydrate into a rotary furnace for calcination at the temperature of 400-420 ℃ for 9-12h, then discharging, carrying out air flow crushing on the discharged material, screening for removing iron, and carrying out vacuum packaging to obtain the battery-grade anhydrous ferric phosphate.
The pickling iron oxide red of the steel plant requires Fe2O3More than or equal to 99.2 percent, Mn less than or equal to 500ppm and other metal ions less than 50 ppm.
The concentration of the phosphoric acid solution is 5-6mol/L, the molar ratio of iron oxide red in acid-washed iron oxide red of a steel plant to phosphoric acid in the phosphoric acid solution is 1:2.1-2.2, the stirring speed of stirring reaction of the acid-washed iron oxide red of the steel plant and the phosphoric acid solution is 300-400r/min, the obtained filter residue is added with pure water for washing, and the obtained washing water is mixed with 12-15mol/L concentrated phosphoric acid solution to prepare 5-6mol/L phosphoric acid solution for returning.
The molar ratio of iron to urea in the filtrate is 1: 0.7 to 1, adding urea to react, and stirring at the rotating speed of 150 to 250 r/min.
And when the first filter residue is subjected to primary slurrying, the solid-liquid ratio is 1:2-3, the temperature of hot pure water is 50-60 ℃, stirring and dispersing are carried out for 15-30min, primary slurrying mother liquor obtained by filtering is mixed with primary washing water, then the primary slurrying mother liquor is mixed with first filtrate, triple effect evaporation is carried out to obtain ammonium phosphate, and evaporated water vapor is condensed to obtain pure water which is returned to wash the first filter residue.
During the secondary slurrying, the solid-liquid ratio is 1:1.5-2, the temperature of hot pure water is 70-85 ℃, and secondary washing water is returned for primary slurrying.
And the battery-grade ferric phosphate dihydrate is calcined in a rotary furnace until the high-temperature moisture content of the ferric phosphate is lower than 0.5%, and then the ferric phosphate is discharged.
The method for measuring the high-temperature moisture comprises the steps of weighing 5g of materials, placing the materials into a crucible, calcining the materials in a muffle furnace at 520 ℃ for 4 hours, taking the materials out, placing the materials into a drying dish for cooling, weighing the materials, and determining the ratio of the weight difference of the materials to the original weight of the materials as the high-temperature moisture.
The invention adopts pickling iron oxide red of an iron and steel plant as a raw material, the raw material is cheap and easy to obtain, the current market price is 100-200 yuan/ton, and the iron oxide red has high content, low impurity content and high yield, is a byproduct of the iron and steel plant, and has low price.
The raw material is taken as an iron source, compared with other iron sources, anions do not exist, the iron content is high, the iron source is added into a phosphoric acid solution, and iron oxide red reacts with excessive phosphoric acid at high temperature to obtain FePO4.H3PO4Filtering the solution to obtain filtrate, adding urea into the filtrate, decomposing at high temperature to obtain carbon dioxide and ammonia, dissolving ammonia in water, and reacting with phosphoric acid to gradually react FePO4.H3PO4The hydrogen ions in the catalyst are consumed, so that FePO is generated4.H3PO4Conversion to FePO4And (3) precipitating, wherein the urea can dissolve substances in water, and hydroxide ions are uniformly distributed in the solution through pyrolysis, and after the pH value reaches a certain value, the ferric phosphate can be uniformly precipitated, so that the particle size distribution of the ferric phosphate is narrow.
And filtering to obtain iron phosphate and ammonium phosphate mother liquor, concentrating and crystallizing the ammonium phosphate mother liquor to obtain ammonium phosphate, slurrying and washing the obtained iron phosphate, drying by microwave, and calcining by a rotary furnace to obtain the anhydrous iron phosphate.
The washing is divided into two-step pulping and two-step washing, the second washing liquid returns to the first-step pulping, the washing efficiency is high, and meanwhile, water is saved.
This patent is through pickling iron oxide red of steel plant as the raw materials, and the cost of the anhydrous ferric phosphate of battery grade of preparation is less than 7000 yuan, compares 8000-10000 yuan per ton cost on the current market, greatly reduced, and the waste water volume of production also reduces by conventional technology every ton product 50-100 tons and is less than 30 tons of this patent.
Meanwhile, ammonium phosphate in the fertilizer can be recovered, and the fertilizer is an agricultural compound fertilizer.
Compared with the conventional process, the method for preparing the iron phosphate by the homogeneous phase method avoids local over-concentration and condition fluctuation in the production process, and the obtained iron phosphate is narrow in particle size distribution, good in consistency and high in purity.
The invention has the beneficial effects that: the method has the advantages of short flow, low cost, simple operation and less sewage generation, and can obtain the battery grade iron phosphate with narrow particle size distribution, good consistency and high purity.
Drawings
Fig. 1 is a laser particle size distribution plot of battery grade iron phosphate of example 1 of the present invention.
Detailed Description
The invention will be described in detail with reference to the following specific drawings and examples, and the preparation method of the battery-grade anhydrous iron phosphate of the embodiment is that acid-washed iron oxide red of a steel plant is mixed with a phosphoric acid solution, stirred and reacted for 1-2 hours at the temperature of 95-100 ℃, and then filtered to obtain filtrate and filter residue;
adding urea into the obtained filtrate, then continuously heating to the temperature of 95-100 ℃, stirring for reacting for 2-3h until the end point pH is 2.1-2.2, then stopping stirring, pouring out the materials and filtering to obtain a first filtrate and a first filter residue;
adding hot pure water into the first filter residue, stirring and dispersing for primary slurrying, filtering the obtained primary slurried material, washing for 20-25min, discharging the material, adding hot pure water for secondary slurrying, filtering the obtained secondary slurried material, washing for 10-15min, and discharging the washed material;
carrying out microwave drying on the washed materials by a microwave dryer, and then screening and electromagnetically removing iron to obtain battery-grade ferric phosphate dihydrate;
adding battery-grade ferric phosphate dihydrate into a rotary furnace for calcination at the temperature of 400-420 ℃ for 9-12h, then discharging, carrying out air flow crushing on the discharged material, screening for removing iron, and carrying out vacuum packaging to obtain the battery-grade anhydrous ferric phosphate.
The pickling iron oxide red of the steel plant requires Fe2O3More than or equal to 99.2 percent, Mn less than or equal to 500ppm and other metal ions less than 50 ppm.
The concentration of the phosphoric acid solution is 5-6mol/L, the molar ratio of iron oxide red in acid-washed iron oxide red of a steel plant to phosphoric acid in the phosphoric acid solution is 1:2.1-2.2, the stirring speed of stirring reaction of the acid-washed iron oxide red of the steel plant and the phosphoric acid solution is 300-400r/min, the obtained filter residue is added with pure water for washing, and the obtained washing water is mixed with 12-15mol/L concentrated phosphoric acid solution to prepare 5-6mol/L phosphoric acid solution for returning.
The molar ratio of iron to urea in the filtrate is 1: 0.7 to 1, adding urea to react, and stirring at the rotating speed of 150 to 250 r/min.
And when the first filter residue is subjected to primary slurrying, the solid-liquid ratio is 1:2-3, the temperature of hot pure water is 50-60 ℃, stirring and dispersing are carried out for 15-30min, primary slurrying mother liquor obtained by filtering is mixed with primary washing water, then the primary slurrying mother liquor is mixed with first filtrate, triple effect evaporation is carried out to obtain ammonium phosphate, and evaporated water vapor is condensed to obtain pure water which is returned to wash the first filter residue.
During the secondary slurrying, the solid-liquid ratio is 1:1.5-2, the temperature of hot pure water is 70-85 ℃, and secondary washing water is returned for primary slurrying.
And the battery-grade ferric phosphate dihydrate is calcined in a rotary furnace until the high-temperature moisture content of the ferric phosphate is lower than 0.5%, and then the ferric phosphate is discharged.
The method for measuring the high-temperature moisture comprises the steps of weighing 5g of materials, placing the materials into a crucible, calcining the materials in a muffle furnace at 520 ℃ for 4 hours, taking the materials out, placing the materials into a drying dish for cooling, weighing the materials, and determining the ratio of the weight difference of the materials to the original weight of the materials as the high-temperature moisture.
Example 1
A preparation method of battery-grade anhydrous iron phosphate comprises the steps of mixing acid-washed iron oxide red of a steel plant with a phosphoric acid solution, stirring and reacting for 1.5 hours at the temperature of 98 ℃, and then filtering to obtain filtrate and filter residue;
adding urea into the obtained filtrate, then continuously heating to 99 ℃, stirring for reacting for 2.5h until the end point pH is 2.15, then stopping stirring, pouring out the materials and filtering to obtain a first filtrate and a first filter residue;
adding hot pure water into the first filter residue, stirring and dispersing to perform primary slurrying, filtering the obtained primary slurried material, washing for 23min, discharging the material, adding hot pure water to perform secondary slurrying, filtering the obtained secondary slurried material, washing for 13min, and discharging the washed material;
carrying out microwave drying on the washed materials by a microwave dryer, and then screening and electromagnetically removing iron to obtain battery-grade ferric phosphate dihydrate;
adding battery-grade ferric phosphate dihydrate into a rotary furnace for calcination at the temperature of 415 ℃ for 11h, then discharging, carrying out air flow crushing on the discharged material, screening for removing iron, and carrying out vacuum packaging to obtain the battery-grade anhydrous ferric phosphate.
The pickling iron oxide red of the steel plant requires Fe2O3More than or equal to 99.2 percent, Mn less than or equal to 500ppm and other metal ions less than 50 ppm.
The concentration of the phosphoric acid solution is 5.5mol/L, the molar ratio of iron oxide red in acid-washed iron oxide red of a steel plant to phosphoric acid in the phosphoric acid solution is 1:2.15, the stirring speed of the acid-washed iron oxide red of the steel plant and the phosphoric acid solution during stirring reaction is 380r/min, the obtained filter residue is added with pure water for washing, and the obtained washing water is mixed with 14mol/L concentrated phosphoric acid solution to prepare 5.5mol/L phosphoric acid solution for returning use.
The molar ratio of iron to urea in the filtrate is 1: 0.85, adding urea, reacting and stirring at the rotating speed of 225 r/min.
And when the first filter residue is subjected to primary slurrying, the solid-liquid ratio is 1:3, the temperature of hot pure water is 55 ℃, stirring and dispersing are carried out for 25min, primary slurrying mother liquor obtained by filtering is mixed with primary washing water, then the primary slurrying mother liquor is mixed with the first filtrate, ammonium phosphate is obtained through triple effect evaporation, and water vapor obtained through evaporation is condensed to obtain pure water which is returned to wash the first filter residue.
And during secondary slurrying, the solid-liquid ratio is 1:1.8, the temperature of hot pure water is 80 ℃, and secondary washing water is returned to perform primary slurrying.
And the battery-grade ferric phosphate dihydrate is calcined in a rotary furnace until the high-temperature moisture content of the ferric phosphate is lower than 0.5%, and then the ferric phosphate is discharged.
The method for measuring the high-temperature moisture comprises the steps of weighing 5g of materials, placing the materials into a crucible, calcining the materials in a muffle furnace at 520 ℃ for 4 hours, taking the materials out, placing the materials into a drying dish for cooling, weighing the materials, and determining the ratio of the weight difference of the materials to the original weight of the materials as the high-temperature moisture.
As shown in fig. 1, the particle size distribution of the iron phosphate obtained in this example is narrow, and the finally obtained detection data of the battery-grade iron phosphate are as follows:
| index (I) | Fe+PO4 | Iron to phosphorus molar ratio | Nitrate radical | Cl | Sulfate radical |
| Numerical value | 99.89％ | 0.995 | 1.1ppm | 29ppm | 8ppm |
| Zn | Cu | Ni | Cr | Pb | Ca |
| 6.1ppm | 0.1ppm | 2.7ppm | 6.1ppm | 1.2ppm | 12.4ppm |
| Mn | Mg | Cd | Co | K | NH4+ |
| 10.3ppm | 5.7ppm | 0.3ppm | 2.1ppm | 1.9ppm | 1.9ppm |
| D10 | D50 | D90 | (D90-D10)/D50 | BET | Tap density |
| 0.39 micron | 0.48 micron | 0.61 micron | 0.458 | 7.9m2/g | 1.3g/mL |
Example 2
A preparation method of battery-grade anhydrous iron phosphate comprises the steps of mixing acid-washed iron oxide red of a steel plant with a phosphoric acid solution, stirring and reacting for 1.5 hours at the temperature of 98 ℃, and then filtering to obtain filtrate and filter residue;
adding urea into the obtained filtrate, then continuously heating to the temperature of 98 ℃, stirring for reacting for 3 hours until the pH value at the end point is 2.17, then stopping stirring, pouring out the materials, and filtering to obtain a first filtrate and a first filter residue;
adding hot pure water into the first filter residue, stirring and dispersing to perform primary slurrying, filtering the obtained primary slurried material, washing for 24min, discharging the material, adding hot pure water to perform secondary slurrying, filtering the obtained secondary slurried material, washing for 14min, and discharging the washed material;
carrying out microwave drying on the washed materials by a microwave dryer, and then screening and electromagnetically removing iron to obtain battery-grade ferric phosphate dihydrate;
adding battery-grade ferric phosphate dihydrate into a rotary furnace for calcination at the temperature of 415 ℃ for 12h, discharging, carrying out air flow crushing on the discharged material, screening for removing iron, and carrying out vacuum packaging to obtain the battery-grade anhydrous ferric phosphate.
The pickling iron oxide red of the steel plant requires Fe2O3More than or equal to 99.2 percent, Mn less than or equal to 500ppm and other metal ions less than 50 ppm.
The concentration of the phosphoric acid solution is 5.8mol/L, the molar ratio of iron oxide red in acid-washed iron oxide red of a steel plant to phosphoric acid in the phosphoric acid solution is 1:2.16, the stirring speed of the acid-washed iron oxide red of the steel plant and the phosphoric acid solution during stirring reaction is 385r/min, the obtained filter residue is added with pure water for washing, and the obtained washing water and 14mol/L concentrated phosphoric acid solution are mixed to prepare 5.8mol/L phosphoric acid solution for returning use.
The molar ratio of iron to urea in the filtrate is 1: 0.9, adding urea, and stirring at the rotating speed of 220 r/min.
And when the first filter residue is subjected to primary slurrying, the solid-liquid ratio is 1:3, the temperature of hot pure water is 55 ℃, stirring and dispersing are carried out for 25min, primary slurrying mother liquor obtained by filtering is mixed with primary washing water, then the primary slurrying mother liquor is mixed with the first filtrate, ammonium phosphate is obtained through triple effect evaporation, and water vapor obtained through evaporation is condensed to obtain pure water which is returned to wash the first filter residue.
And during secondary slurrying, the solid-liquid ratio is 1:1.8, the temperature of hot pure water is 80 ℃, and secondary washing water is returned to perform primary slurrying.
And the battery-grade ferric phosphate dihydrate is calcined in a rotary furnace until the high-temperature moisture content of the ferric phosphate is lower than 0.5%, and then the ferric phosphate is discharged.
The method for measuring the high-temperature moisture comprises the steps of weighing 5g of materials, placing the materials into a crucible, calcining the materials in a muffle furnace at 520 ℃ for 4 hours, taking the materials out, placing the materials into a drying dish for cooling, weighing the materials, and determining the ratio of the weight difference of the materials to the original weight of the materials as the high-temperature moisture.
The finally obtained detection data of the battery-grade iron phosphate are as follows:
| index (I) | Fe+PO4 | Iron to phosphorus molar ratio | Nitrate radical | Cl | Sulfate radical |
| Numerical value | 99.87％ | 0.996 | 1.0ppm | 27ppm | 9ppm |
| Zn | Cu | Ni | Cr | Pb | Ca |
| 6.9ppm | 0.1ppm | 2.1ppm | 5.1ppm | 1.1ppm | 11.4ppm |
| Mn | Mg | Cd | Co | K | NH4+ |
| 10.9ppm | 5.1ppm | 0.1ppm | 2.3ppm | 1.4ppm | 1.6ppm |
| D10 | D50 | D90 | (D90-D10)/D50 | BET | Tap density |
| 0.38 micron | 0.47 micron | 0.61 micron | 0.489 | 7.7m2/g | 1.3g/mL |
Example 3
A preparation method of battery-grade anhydrous iron phosphate comprises the steps of mixing acid-washed iron oxide red of a steel plant with a phosphoric acid solution, stirring and reacting for 2 hours at the temperature of 100 ℃, and then filtering to obtain filtrate and filter residue;
adding urea into the obtained filtrate, then continuously heating to 99 ℃, stirring for reacting for 2.5h until the end point pH is 2.18, then stopping stirring, pouring out the materials and filtering to obtain a first filtrate and a first filter residue;
adding hot pure water into the first filter residue, stirring and dispersing to perform primary slurrying, filtering the obtained primary slurried material, washing for 25min, discharging the material, adding hot pure water to perform secondary slurrying, filtering the obtained secondary slurried material, washing for 14min, and discharging the washed material;
carrying out microwave drying on the washed materials by a microwave dryer, and then screening and electromagnetically removing iron to obtain battery-grade ferric phosphate dihydrate;
adding battery-grade ferric phosphate dihydrate into a rotary furnace for calcination at the temperature of 415 ℃ for 11.5h, then discharging, carrying out air flow crushing on the discharged material, screening for removing iron, and carrying out vacuum packaging to obtain the battery-grade anhydrous ferric phosphate.
The pickling iron oxide red of the steel plant requires Fe2O3More than or equal to 99.2 percent, Mn less than or equal to 500ppm and other metal ions less than 50 ppm.
The concentration of the phosphoric acid solution is 5.5mol/L, the molar ratio of iron oxide red in acid-washed iron oxide red of a steel plant to phosphoric acid in the phosphoric acid solution is 1:2.16, the stirring speed of the acid-washed iron oxide red of the steel plant and the phosphoric acid solution during stirring reaction is 350r/min, the obtained filter residue is added with pure water for washing, and the obtained washing water is mixed with 14mol/L concentrated phosphoric acid solution to prepare 5.5mol/L phosphoric acid solution for returning use.
The molar ratio of iron to urea in the filtrate is 1: 0.85, adding urea, reacting and stirring at the rotating speed of 195 r/min.
And when the first filter residue is subjected to primary slurrying, the solid-liquid ratio is 1:2.5, the temperature of hot pure water is 55 ℃, stirring and dispersing are carried out for 25min, primary slurrying mother liquor obtained by filtering is mixed with primary washing water, then the primary slurrying mother liquor is mixed with the first filtrate, triple effect evaporation is carried out to obtain ammonium phosphate, and water vapor obtained by evaporation is condensed to obtain pure water which is returned to wash the first filter residue.
And during secondary slurrying, the solid-liquid ratio is 1:1.8, the temperature of hot pure water is 80 ℃, and secondary washing water is returned to perform primary slurrying.
And the battery-grade ferric phosphate dihydrate is calcined in a rotary furnace until the high-temperature moisture content of the ferric phosphate is lower than 0.5%, and then the ferric phosphate is discharged.
The method for measuring the high-temperature moisture comprises the steps of weighing 5g of materials, placing the materials into a crucible, calcining the materials in a muffle furnace at 520 ℃ for 4 hours, taking the materials out, placing the materials into a drying dish for cooling, weighing the materials, and determining the ratio of the weight difference of the materials to the original weight of the materials as the high-temperature moisture.
The finally obtained detection data of the battery-grade iron phosphate are as follows:
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 (8)
1. A preparation method of battery-grade anhydrous iron phosphate is characterized in that acid-washed iron oxide red in a steel plant is mixed with a phosphoric acid solution, stirred and reacted for 1-2 hours at the temperature of 95-100 ℃, and then filtered to obtain filtrate and filter residue;
adding urea into the obtained filtrate, then continuously heating to the temperature of 95-100 ℃, stirring for reacting for 2-3h until the end point pH is 2.1-2.2, then stopping stirring, pouring out the materials and filtering to obtain a first filtrate and a first filter residue;
adding hot pure water into the first filter residue, stirring and dispersing for primary slurrying, filtering the obtained primary slurried material, washing for 20-25min, discharging the material, adding hot pure water for secondary slurrying, filtering the obtained secondary slurried material, washing for 10-15min, and discharging the washed material;
carrying out microwave drying on the washed materials by a microwave dryer, and then screening and electromagnetically removing iron to obtain battery-grade ferric phosphate dihydrate;
adding battery-grade ferric phosphate dihydrate into a rotary furnace for calcination at the temperature of 400-420 ℃ for 9-12h, then discharging, carrying out air flow crushing on the discharged material, screening for removing iron, and carrying out vacuum packaging to obtain the battery-grade anhydrous ferric phosphate.
2. The method of claim 1 for preparing battery grade anhydrous iron phosphate, characterized in that: the pickling iron oxide red of the steel plant requires Fe2O3More than or equal to 99.2 percent, Mn less than or equal to 500ppm and other metal ions less than 50 ppm.
3. The method of claim 1 for preparing battery grade anhydrous iron phosphate, characterized in that: the concentration of the phosphoric acid solution is 5-6mol/L, the molar ratio of iron oxide red in acid-washed iron oxide red of a steel plant to phosphoric acid in the phosphoric acid solution is 1:2.1-2.2, the stirring speed of stirring reaction of the acid-washed iron oxide red of the steel plant and the phosphoric acid solution is 300-400r/min, the obtained filter residue is added with pure water for washing, and the obtained washing water is mixed with 12-15mol/L concentrated phosphoric acid solution to prepare 5-6mol/L phosphoric acid solution for returning.
4. The method of claim 1 for preparing battery grade anhydrous iron phosphate, characterized in that: the molar ratio of iron to urea in the filtrate is 1: 0.7 to 1, adding urea to react, and stirring at the rotating speed of 150 to 250 r/min.
5. The method of claim 1 for preparing battery grade anhydrous iron phosphate, characterized in that: and when the first filter residue is subjected to primary slurrying, the solid-liquid ratio is 1:2-3, the temperature of hot pure water is 50-60 ℃, stirring and dispersing are carried out for 15-30min, primary slurrying mother liquor obtained by filtering is mixed with primary washing water, then the primary slurrying mother liquor is mixed with first filtrate, triple effect evaporation is carried out to obtain ammonium phosphate, and evaporated water vapor is condensed to obtain pure water which is returned to wash the first filter residue.
6. The method of claim 1 for preparing battery grade anhydrous iron phosphate, characterized in that: during the secondary slurrying, the solid-liquid ratio is 1:1.5-2, the temperature of hot pure water is 70-85 ℃, and secondary washing water is returned for primary slurrying.
7. The method of claim 1 for preparing battery grade anhydrous iron phosphate, characterized in that: and the battery-grade ferric phosphate dihydrate is calcined in a rotary furnace until the high-temperature moisture content of the ferric phosphate is lower than 0.5%, and then the ferric phosphate is discharged.
8. The method of claim 7, wherein the method comprises the steps of: the method for measuring the high-temperature moisture comprises the steps of weighing 5g of materials, placing the materials into a crucible, calcining the materials in a muffle furnace at 520 ℃ for 4 hours, taking the materials out, placing the materials into a drying dish for cooling, weighing the materials, and determining the ratio of the weight difference of the materials to the original weight of the materials as the high-temperature moisture.
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| CN113772734A (en) * | 2021-11-04 | 2021-12-10 | 四川省盈达锂电新材料有限公司 | Method for recovering manganese and iron resources from manganese slag |
| CN114180547A (en) * | 2021-12-31 | 2022-03-15 | 常州锂源新能源科技有限公司 | Preparation method of low-cost high-power lithium iron phosphate |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113772734A (en) * | 2021-11-04 | 2021-12-10 | 四川省盈达锂电新材料有限公司 | Method for recovering manganese and iron resources from manganese slag |
| CN114180547A (en) * | 2021-12-31 | 2022-03-15 | 常州锂源新能源科技有限公司 | Preparation method of low-cost high-power lithium iron phosphate |
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