Process for the separation of cadmium (Cd++)-ions from sewage, waste water and aqueous solutions

Claim 1

A process for the separation of cadmium (Cd ++ )-ions from aqueous liquids in which said cadmium ions are present as complexes of nitrilotriacetic acid, ethylenediamine tetraacetic acid and/or diethylenetriamino pentaacetic acid or their anionic salts, comprising contacting salt liquids with an HS-containing triazine compound of the general formula ##STR3## in which: R is hydrogen, the same or different alkyl with 1 to 3 carbons, --NR 1 R 2 or --OR 3 ; R 1 , r 2 and R 3 are hydrogen, the same or different alkyl with 1 to 6 carbons or phenyl; n is a whole number from 0 to 2; or a water-soluble salt thereof to precipitate said cadmium ions and wherein said compound is contacted in an amount such that at least one equivalent of mercapto or mercaptide groups is present per equivalent of cadmium ions the precipitation of the Cd +++ -ions takes place in the presence of an at least equivalent quantity of Fe +++ -ions, based on said complexing agent in said liquid, wherein said precipitation takes place at a pH value between 4 and 10, and separating the precipitate from the aqueous liquid.