Preparation method of battery-grade iron phosphate

Abstract

The invention provides a preparation method of battery-grade iron phosphate. The preparation method comprises the following steps: adding high-purity iron powder into hydrochloric acid with a proper concentration, and carrying out a reaction until the iron powder is not dissolved any more; filtering, adding a proper amount of hydrogen peroxide, and reacting until no ferrous ions exist in the reaction solution; adding phosphoric acid, uniformly stirring, and carrying out spray drying to obtain iron phosphate dihydrate; and sintering at a high temperature to remove crystal water to obtain anhydrous iron phosphate. According to the invention, the method comprises the steps of ferrous solution synthesis, oxidation, ferric phosphate dihydrate synthesis and high-temperature sintering, so that the procedures of ferric phosphate precipitation, aging, filtering, washing and the like are reduced, the procedures are reduced, the flow is shortened, the production period is shortened, the production efficiency is improved, water resources are saved, and the cost is low; the raw materials are recycled, no solid waste is generated, and the cost is reduced; and a neutralizer is not needed, the useof raw materials is reduced, the opportunity of impurity introduction is reduced, the obtained product is high in purity and low in impurity content, and the market requirements of battery-grade rawmaterials can be well met.

Description

technical field [0001] The invention belongs to the technical field of preparation of lithium-ion battery materials, and in particular relates to a method for preparing battery-grade iron phosphate. Background technique [0002] The synthesis process routes of lithium iron phosphate, the cathode material of lithium ion batteries, include hydrothermal process, ferrous oxalate process, iron red process, and iron phosphate process. The iron phosphate process has gradually become the mainstream route for lithium iron phosphate production due to its good batch stability and excellent electrochemical performance. The ferric phosphate in the prior art is a conventional chemical precipitation method, and the production process is: batching—ferrous oxidation—ferric phosphate precipitation—filtering and washing—low temperature drying—high temperature sintering, etc. For example, CN201910630953.9 discloses a method for preparing battery-grade iron phosphate. The preparation method co...

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Problems solved by technology

[0003] In the prior art, the iron phosphate production process is relatively complicated, the energy consumption is high, and the water consumption during washing is large, and the cost of sewage treatment is high; secondly, the raw materials cannot be reused, such as neutralizer liquid alkali or ammonia water, which cannot be reused, and finally form a solid Salt, or even if it is reused, a large amount of calcium sulfate will be produced, and the amount of solid waste will be large; moreover, due to the use of more raw materials in the prior art, and the complicated process, there are many opportunities to introduce impurities, resulting in the purity of the product not tall

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