Method for the hydrometallurgical recovery of lithium from the fraction of used galvanic cells containing lithium, iron and phosphate

The invention relates to a method for the hydrometallurgical recovery of lithium from the fraction of used galvanic cells containing lithium, iron and phosphate. According to the invention, a fraction containing lithium, iron and phosphate having an aluminum content of up to 5% by weight, and having a particle size of up to 150 mu m, is introduced into sulfuric acid having a concentration of 0.5 to 3 mol/l in an amount that is at least stoichiometric relative to the lithium content of the fraction containing lithium, iron and phosphate and in a solid-to-liquid ratio in the range of 100 to 750 g/l, hydrogen peroxide is added in an amount that is at least stoichiometric relative to the iron content which is to be oxidized of the lithium iron phosphate-containing fraction or a lithium iron phosphate-containing fraction having an aluminum content of up to 5% by weight, and having a particle size of up to 500 mu m, is introduced into hydrochloric acid having a concentration of 0.5 to 3 mol/l in an amount that is at least stoichiometric relative to the lithium content of the lithium iron phosphate-containing fraction and in a solid-to-liquid ratio in the range of 50 to 450 g/l, hydrogen peroxide is solublized at temperature of between 25-70 DEG C in an amount that is at least stoichiometric relative to the iron content which is to be oxidised of the lithium iron phosphate-containing fraction or a lithium iron phosphate-containing fraction, the solution that contains the lithium sulphate solution or lithium chloride solution is separated off and the remaining residue is washed at least twice, the wash solution containing the separated lithium sulphate and the lithium sulphate and the wash solutions containing the lithium chloride and the lithium chloride are combined, and are converted to lithium hydroxide by electrodialysis on bipolar membranes.