A kind of preparation method of battery grade iron phosphate with low sulfur content

Abstract

The invention discloses a method for preparing battery-grade iron phosphate with low sulfur content, which comprises the following steps: S1, adding ferric sulfate solution into phosphate solution, heating under stirring, and performing synthesis reaction, when the reaction slurry is transformed into Pure white, press filter the reaction slurry to collect the filter cake; S2, disperse the filter cake obtained by the above operation into water, heat and keep warm, and obtain the phosphoric acid slurry; S3, wash and filter to remove the surface water, Calcined iron phosphate products. Compared with the desulfurization technology in the prior art, the solution of the present invention does not need to add any surfactant, avoids the use of emulsifiers such as sodium cetyl sulfonate and sodium stearate, and greatly eases the pressure of environmental protection treatment. It not only solves the technical problem that the sulfur content is difficult to control in the existing iron phosphate preparation technology, but also reduces the amount of washing water in the washing process and relieves the pressure of wastewater treatment.

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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