Preparation method of battery-grade anhydrous iron phosphate

An anhydrous phosphoric acid, battery-level technology, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problem of high iron source cost, affecting the performance of lithium iron phosphate and lithium iron phosphate batteries, high impurity content in iron phosphate, etc. problems, to achieve the effect of improving performance and eliminating differences in microscopic components

Active Publication Date: 2019-11-22
安徽丰原锂电能源有限公司 +1
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Problems solved by technology

[0004] The cost of the iron source used in the above ferric phosphate preparation method is relatively high, and there is also the problem of high content of impurities such as potassium, sodium, magnesium and heavy metals in the prepared ferric phosphate, the existence of these impurities will affect the further prepared lithium iron phosphate And the performance of lithium iron phosphate battery

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  • Preparation method of battery-grade anhydrous iron phosphate
  • Preparation method of battery-grade anhydrous iron phosphate
  • Preparation method of battery-grade anhydrous iron phosphate

Examples

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Embodiment 1

[0032] The preparation method of battery-grade anhydrous iron phosphate of the present embodiment, process flow chart sees figure 1 As shown, the scraps of cold-rolled iron plates for automobiles are used as the iron source, reacted with a dilute sulfuric acid solution with a concentration of 20%, and reacted for 3 hours under stirring conditions to generate a ferrous sulfate solution, which is added with a decontamination agent Impurity removal, settling filtration, and the obtained filtrate is the purified ferrous sulfate solution;

[0033] Adjust the pH value of the purified ferrous sulfate solution to 2.0 with phosphoric acid-urea mixed solution, and then add a flocculant to remove impurities. The amount of the flocculant is 0.05% of the mass of the ferrous sulfate solution. A mixture of iron and EDTA at a weight ratio of 2:1, after adding the flocculant, the stirring speed is 100r / min, the stirring time is 5min, and then the residue is removed by filtration to obtain a gr...

Embodiment 2

[0041] The preparation method of the battery-grade anhydrous iron phosphate in this embodiment uses ferrous sulfate, a by-product of producing titanium dioxide by the sulfuric acid method, as the iron source. Specifically, Ti(SO 4 ) 2 and TiOSO 4 , while producing FeSO 4 and Fe 2 (SO 4 ) 3 , TiOSO produced by acid hydrolysis 4 and FeSO 4 After leaching and sedimentation to remove insoluble impurities, the solution is added to the waste iron sheet for reduction reaction after removing impurities, so that the ferric ions in the solution exist in the form of ferrous ions, TiOSO 4 to Ti 2 (SO 4 ) 3 form exists. After purification and reduction treatment, the titanium liquid is concentrated and cooled in vacuum to make the ferrous sulfate 4 ·7H 2 Form O was crystallized and dried by centrifugation, which was the raw material of this example.

[0042] Add water to dissolve the ferrous sulfate produced by the sulfuric acid method to produce titanium dioxide, then filter...

Embodiment 3

[0049] The preparation method of the battery-grade anhydrous iron phosphate in this embodiment uses the scraps of cold-rolled iron plates for automobiles as the iron source, reacts with a dilute sulfuric acid solution with a concentration of 20%, and reacts for 3 hours under stirring conditions to generate ferrous sulfate solution, the ferrous sulfate solution is added with a decontamination agent for decontamination, sedimentation and filtration, and the filtrate obtained is the purified ferrous sulfate solution;

[0050] Adjust the pH value of the purified ferrous sulfate solution to 2.0 with phosphoric acid-urea mixed solution, then add flocculant to remove impurities, the amount of flocculant is 0.05% of the mass of ferrous sulfate solution, the flocculant is a mixed flocculant, specifically No. A mixture of flocculant and EDTA in a weight ratio of 2:1, after adding the flocculant, the stirring speed is 100r / min, the stirring time is 5min, and then the residue is removed by...

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Abstract

The invention belongs to the technical field of battery material preparation, and particularly discloses a preparation method of battery-grade anhydrous iron phosphate. The method includes preparing aferrous solution by adopting cold-rolled iron plate leftover materials and/or beneficiation reduced iron powder as an iron source, or preparing a ferrous solution by adopting by-product ferrous sulfate of sulfuric acid method titanium dioxide production; then removing impurities by using a flocculating agent; then oxidizing ferrous ions into ferric ions; mixing the ferric ions with a solution containing phosphate ions; adding a dispersing agent; carrying out crystallization reaction to obtain iron phosphate crystals; subjecting the iron phosphate crystals to drying and roasting to obtain thebattery-grade anhydrous iron phosphate. According to the preparation method, low-cost cold-rolled iron plate leftover materials, beneficiation reduced iron powder or byproduct ferrous sulfate in a sulfuric acid method titanium dioxide production process is used as an iron source for preparation; the flocculating agent is adopted for impurity removal, and then crystallization is performed to prepare the battery-grade anhydrous iron phosphate. The method has the advantages of low raw material cost, high product purity and high tap density, is of a spherical structure, and can be used as a precursor of lithium iron phosphate with high tap density.

Description

technical field [0001] The invention relates to the technical field of battery material preparation, in particular to a method for preparing battery-grade anhydrous iron phosphate. Background technique [0002] Lithium iron phosphate (LiFePO 4 ) The lithium battery assembled with positive electrode material has the advantages of excellent cycle performance, good thermal stability, wide source of raw materials and no pollution. LiFePO 4 It is considered to be a good cathode material for lithium-ion batteries. However, compared with other positive electrode materials, lithium iron phosphate has a lower tap density, resulting in lower energy density and volume specific capacity, so it cannot meet the requirements of high-energy and high-density battery materials. Therefore, how to increase the tap density of lithium iron phosphate has become a hot spot for lithium iron phosphate manufacturers to explore. After research, it has been found that if the particle size of lithium ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/37
CPCC01B25/375C01P2004/03C01P2004/32C01P2004/61C01P2006/11C01P2006/12C01P2006/82
Inventor 王立卓王宇飞周知斌王宝璐孙浩
Owner 安徽丰原锂电能源有限公司
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