Method for synthesizing iron phosphate by utilizing titanium dioxide byproduct ferrous sulfate

Abstract

The invention discloses a method for synthesizing iron phosphate by utilizing a titanium dioxide byproduct ferrous sulfate. According to the method, the titanium dioxide byproduct ferrous sulfate is used as a raw material, through pretreatment, oxidation of ferrous sulfate in advance, partial substitution of phosphoric acid with sulfuric acid or hydrogen chloride and other inorganic acids to serveas acidizing fluid, generation of Mn3(PO4)2 and Mg3(PO4)2 precipitates in the iron phosphate preparation process is effectively inhibited, therefore the iron phosphate finished product with the low impurity Mn, Mg and S element content is prepared. Meanwhile, the utilization rate of iron ions is increased, and the iron-phosphorus ratio of the prepared iron phosphate is obviously higher than thatof the related technology. According to the method, complex and tedious operations such as extraction, recrystallization and sulfide precipitation are avoided, the titanium dioxide byproduct ferrous sulfate is successfully utilized to prepare the iron phosphate with low impurity content and high iron-phosphorus ratio, the process is simple, and the effect is remarkable.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery materials, in particular to a method for synthesizing ferric phosphate by using ferrous sulfate, a by-product of titanium dioxide. Background technique [0002] Due to the advantages of large theoretical discharge capacity, long cycle life, high safety, and environmental friendliness, lithium iron phosphate is considered to be one of the most promising cathode materials for lithium-ion batteries, and is widely used in various mobile communication devices and vehicles. . Among them, iron phosphate is an important precursor for the production of lithium iron phosphate, and the purity and quality of iron phosphate have an extremely important impact on the electrochemical performance of lithium iron phosphate batteries. For iron phosphate production enterprises, in the face of the plight of continuous rising raw material prices, how to reduce the cost of raw and auxiliary materials and en...

AI Technical Summary

Problems solved by technology

The precipitation method is to remove the impurity manganese and magnesium in ferrous sulfate by adding sulfide and fluoride respectively, and realize the removal of magnesium ions by using the low solubility of manganese sulfide. Poor, at the same time improper operation will also produce hydrogen sulfide gas, this method has serious potential safety hazards; resin adsorption method is to use resin to different ion adsorption capacity difference to ferrous sulfate to remove impurities, but due to a large amount of divalent Iron ions will be preferentially adsorbed by the resin, and impurities such as manganese and magnesium cannot be effectively removed

Though said method can reduce impurity manganese, magnesium content in ferrous sulfate to a certain extent, thereby make the lower ferric phosphate finished product of manganese, magnesium content, but most methods (as countercurrent extraction, recrystallization, sulfide impurity removal, etc.) has the disadvantages of cumbersome steps and complicated operations

At the same time, these methods only focus on the control of impurity manganese and magnesium in the finished product of iron phosphate, while ignoring the control of sulfur content

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