A process for the recovery of lithium from waste lithium ion batteries or parts thereof is disclosed. The process comprising the steps of (a) providing a particulate material containing a transition metal compound and/or transition metal, wherein the transition metal is selected from the group consisting of Mn, Ni and Co, and wherein further at least a fraction of said Ni and/or Co, if present, are in an oxidation state lower than +2, and at least a fraction of said Mn, if present, is manganese(II)oxide; which particulate material further contains a lithium salt and a fluoride salt, and which particulate material optionally contains calcium provided that the element ratio calcium to fluorine is 1.7 or less or is zero; (b) treating the material provided in step (a) with a polar solvent and an alkaline earth hydroxide; and (c) separating the solids from the liquid, optionally followed by washing the solid residue with a polar solvent such as water provides good separation of lithium in high purity, and recovery of valuable transition metals.