The invention relates to an improved process for the preparation of pharmaceutical active ingredients and also to high purity salts and pharmaceutical compositions prepared by said process. More particularly the invention relates to an economical process for the preparation of the compound having the international non-proprietary name (INN) vortioxetine and the chemical nomenclature 1-[2-(2,4-dimethyl-phenylsulfanyl)-phenyl]-piperazine. Vortioxetine corresponds to the following Formula Still more particularly the invention relates to the preparation of high purity vortioxetine L-(+)-mandelate salt of the Formula IX, the conversion of this salt into other highly pure salts and also to the formulation of said salts.