Production method of battery-grade iron phosphate

Abstract

The invention relates to an ultrasonic production method of high-purity battery-grade iron phosphate. The production method comprises steps as follows: preparing a solution A with the concentration of 0.5-6 mol / L by mixing an iron source, an acid compound and a surfactant in a reaction kettle, preparing a solution B with the concentration of 0.5-6 mol / L by mixing phosphate and an oxidizing agent, adding the solution B to the reaction kettle, heating the solution B and the solution A, introducing the ultrasonic means, after a period of reaction, adding phosphoric acid or mixed acid of the phosphoric acid and other acids for transformation crystallization for several hours until the mixed solution turns milk white, and then filtering, washing, drying and crushing the mixed solution to obtain the battery-grade iron phosphate product. The ultrasonic synthesis method has the advantages that the product yield is high, the iron-to-phosphorus ratio is 0.96-1.00, the particle size is uniform and controllable (D50 is smaller than or equal to 15 mu m), the specific surface is 30.0-85.0 m<2> / g, the impurity content is low, the crystallinity is good, and the like, and the battery-grade iron phosphate is an ideal raw material for manufacturing lithium iron phosphate cathode materials of lithium-ion batteries.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery material production, and in particular relates to a method for producing high-purity battery-grade iron phosphate by ultrasonic waves. Background technique [0002] At present, lithium iron phosphate batteries have been widely used in energy storage equipment, electric tools, electric buses, electric vehicles, recreational vehicles, medical equipment start-ups, military power supplies, etc., especially in electric vehicles and electric buses. High performance, long cycle life, excellent cost performance and so on. For the manufacture of lithium iron phosphate cathode materials, the main raw materials (battery-grade ferrous oxalate, iron red or iron phosphate), lithium salt and phosphorus salt are mixed for solid-phase production at home and abroad. Other methods such as sol-gel method, The disadvantages of liquid phase precipitation, ultrasonic and microwave methods are high impurity ...

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Problems solved by technology

There are many ways to synthesize iron phosphate: (1) Hydrothermal method: For example, Guo Xuefeng, MAL, Kandori, etc. of Nanjing University use this method to prepare iron phosphate. The disadvantage is that the feeding is one-time, and the size of the crystal growth cannot be observed during the whole growth process. Due to the limitation of the size of the autoclave container, it is difficult to realize industrial production; (2) Homogeneous precipitation method: Ye Huanying of Nanchang University, Gong Fuzhong of Guangxi University, etc. use this method to prepare iron phosphate. The disadvantage is that the particle size and specific area are uncontrollable, Poor crystallinity, high impurity content, etc.; (3) Sol-gel method: Lu Yingjun of Lanzhou University adopts this method to prepare iron phosphate. The disadvantages are that the preparation process takes a long time, there are a lot of micropores in the gel, and the drying process product It is easy to produce shrinkage, etc.; (4) Air oxidation method: Liu Lang of Beijing University of Chemical Technology uses this method to prepare iron phosphate, and its disadvantages are high temperature of 150-350 ° C, high energy consumption, high production cost, and difficulty in industrialization; (5) Control Crystallization method: Zhang Zhen of Tsinghua University used this method to prepare iron phosphate. Its disadvantages are serious ammonia pollution in the industrial production site environment, uncontrollable particle size and specific surface area; (6) microemulsion method: the introduction of oil phase impurities, etc., is in theoretical research (7) Microwave radiation crystallization method: in the stage of laboratory research, lack of industrial equipment matching the technology

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