Preparation method of battery-grade iron phosphate with low sulfur content

Abstract

The invention discloses a preparation method of battery-grade iron phosphate with a low sulfur content. The preparation method comprises the following steps: S1, adding a ferric sulfate solution intoa phosphate solution, heating the mixed solution under stirring, carrying out synthetic reaction, carrying out filter pressing on the reaction slurry when the reaction slurry becomes pure white, and collecting the filter cake; S2, dispersing the obtained filter cake into water, heating and maintaining the temperature to obtain phosphoric acid slurry; and S3, washing, carrying out filter pressing,removing water on the surface, and calcining to obtain an iron phosphate finished product. Compared with a desulfurization technology in the prior art, no surfactant is needed, use of emulsifiers suchas sodium hexadecyl sulfonate and sodium stearate is avoided, the pressure of environment-friendly treatment is greatly relieved, the technical problem that the sulfur content is difficult to controlin an existing iron phosphate preparation technology is solved, the washing water consumption in the washing process can be reduced, and the load of wastewater treatment is reduced.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a method for preparing battery-grade iron phosphate with low sulfur content. Background technique [0002] With the rapid development of lithium-ion batteries in the world and the increasing demand for lithium-ion batteries in the domestic market, research on lithium-ion batteries has become a hot topic. Due to its large theoretical discharge capacity, long cycle life, high safety, and environmental friendliness, lithium iron phosphate is considered to be one of the most promising lithium-ion cathode materials, and has been widely used in various mobile communication devices, transportation tool. Iron phosphate is an important precursor for the synthesis of lithium iron phosphate, and its purity and quality have an extremely important impact on the electrochemical performance of lithium iron phosphate batteries. [0003] At present, the method for preparing ferric pho...

AI Technical Summary

Problems solved by technology

Although these measures can effectively reduce the sulfur content in the finished product of iron phosphate, the introduction of macromolecular surfactants such as sodium cetylbenzenesulfonate has increased the pressure on environmental protection wastewater treatment; citric acid, ethanol and hot water The three-stage washing method is too complicated and not conducive to large-scale promotion; in addition, the product pre-crushing treatment will also greatly increase production energy consumption

Therefore, it is very necessary to find a sulfur reduction method that is easy to operate and does not require the introduction of surfactants, so as to effectively solve the technical problems of ferrous sulfate and high sulfur content in ferric phosphate products

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