Method for preparing lithium iron phosphate by recycling waste batteries

A method of preparing lithium iron phosphate by recycling and utilizing waste batteries, comprising:

• pre-processing a waste lithium iron phosphate battery to obtain lithium iron phosphate powder, adding alkaline liquid to the lithium iron phosphate powder, and filtering the lithium iron phosphate powder after adding the alkaline liquid to obtain a filter residue;
• adding an iron source, a lithium source or a phosphorus source to the filter residue, and performing ball milling on the filter residue obtained by adding the iron source, the lithium source or the phosphorous source to obtain a ball-milled product;
• preparing a carbon source solution, and adding a surfactant to the carbon source solution to obtain a mixed solution;
• mixing the ball-milled product and the mixed solution, performing spray pyrolysis on a mixture obtained by mixing the ball-milled product and the mixed solution to obtain a high-temperature powder, spraying atomized water to the high-temperature powder to remove impurities, and then calcining the high-temperature powder after impurity removal to obtain a finished product of lithium iron phosphate;
• wherein a pressure of the spray pyrolysis is 0.3-0.8 MPa and a temperature of the spray pyrolysis is 500-750° C., and wherein a temperature of the calcining is 500-700° C. with a heating rate of 1-5° C./min and a duration of the calcining is 2-10 h.