METHOD FOR PREPARING LITHIUM IRON PHOSPHATE FROM FERRIC HYDROXYPHOSPHATE, AND USE THEREOF

The present disclosure provides a method for preparing lithium iron phosphate from ferric hydroxyphosphate, including: purifying ferrous sulfate to form a ferrous sulfate solution, adding hydrogen peroxide, phosphoric acid, an ammonium dihydrogen phosphate solution and ammonia water into the ferrous sulfate solution and then reacting to form a mixed slurry, holding the mixed slurry at a temperature for a period of time, and then washing with water and subjecting to press filtration to form ferric hydroxyphosphate precursors with different iron-phosphorus ratios; then flash drying, sintering at a high temperature, and pulverizing to obtain ferric hydroxyphosphate precursors with different iron-phosphorus ratios and different specific surface areas; pulverizing and mixing the ferric hydroxyphosphate precursors to obtain finished products of ferric hydroxyphosphate, mixing the ferric hydroxyphosphate with a high iron-phosphorus ratio with the ferric hydroxyphosphate with a low iron-phosphorus ratio according to a certain proportion, then proportioning with a lithium source and an iron source according to a certain proportion, and adding a carbon source and an additive to form a mixed material; and subjecting the aforementioned mixed material to ball milling, sanding, spray drying, sintering, pulverizing, sieving, blending, packaging and the like procedures to obtain a finished product of lithium iron phosphate.