Method for recovering lithium from waste lithium iron phosphate battery and preparing iron phosphate

The invention discloses a method for recovering lithium from a waste lithium iron phosphate battery and preparing iron phosphate. The method for recovering lithium from the waste lithium iron phosphate battery and preparing the iron phosphate comprises the following steps of: (1) after soaking positive electrode powder of a scrapped battery in alkali liquor, roasting the positive electrode powder to obtain an intermediate product; (2) leaching the intermediate product by using an acid solution, and crystallizing or precipitating a leaching solution to obtain a lithium salt product; (3) adding the leaching residues to a phosphoric acid solution, adding high-purity iron powder for a reaction, and obtaining a Fe(H2PO4)2 solution; (4) introducing an oxidizing agent into the Fe(H2PO4)2 solution to carry out oxidation reaction to obtain iron phosphate dihydrate slurry; and (5) carrying out post-treatment on the iron phosphate dihydrate slurry to obtain an iron phosphate product. According to the method for recoveri