Preparation method for lithium iron phosphate precursor without wastewater discharge

The invention provides a preparation method for a lithium iron phosphate precursor without wastewater discharge. The preparation method comprises the steps of diluting concentrated phosphoric acid with deionized water, mixing with pre-activated Fe2O3, or further adding a carbon nanotube to obtain a mixed liquid; performing wet grinding after ultrasonic dispersion on the mixed liquid, performing sieving, and adding a dispersing agent for heating, stirring and dispersing; performing heating reaction on the dispersed paste under an N2 environment, and obtaining a precipitant and a solution aftercooling; and performing high-speed separation on the precipitant and the solution, and drying the precipitant, thereby obtaining an iron phosphate (or iron phosphate/carbon nanotube) precursor. The Fe2O3 and phosphoric acid are used as raw materials, the carbon nanotube can be combined, the lithium iron phosphate precursor is prepared by a hydrothermal method, the preparation process is simple, isshort in time and low in