Patent ID: 9677153
Date: 2017-06-13
CPC Classifications: B01D,C01B,C01D,C22B,Y02P

Claim:
1. A method for the hydrometallurgical recovery of lithium from a lithium-iron-phosphate-containing fraction of used galvanic cells comprising the steps of: introducing the lithium-iron-phosphate-containing fraction having an aluminum content of up to 5% by weight, and having a particle size of up to 500 μm, 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 lithium-iron-phosphate-containing fraction and in a solid-to-liquid ratio in the range of 100 to 750 g/l; and solubilizing the lithium contained in the lithium-iron-phosphate-containing fraction at temperatures of between 25-70° C. with addition of hydrogen peroxide in an amount that is at least stoichiometric relative to the iron content of the lithium-iron-phosphate-containing fraction, wherein a lithium sulfate solution is formed; separating the lithium sulfate solution from a remaining residue; and washing the remaining residue at least twice, wherein a wash solution containing lithium sulfate is formed; wherein the separated lithium sulfate solution and the wash solution containing lithium sulfate are combined and are converted to lithium hydroxide by means of electrodialysis with bipolar membranes.