TREATMENT OF NICKEL-CONTAINING WASTE WATER ON PHOSPHATING

摘要

Method for the treatment of a nickel-containing waste water, comprising a phosphate bath overflow and/or the rinsing water after phosphating, whereby the phosphating is carried out with an acidic aqueous phosphate solution, containing 3 to 50 g/l phosphate ions, calculated as PO4-3, 0.2 to 3 g/l zinc ions, 0.01 to 2.5 g/l nickel ions, optionally further metal ions and optionally accelerator. The phosphate bath overflow and/or post-phosphating rinsing water are run over a weakly acidic ion-exchanger, characterised in that the acid groups of the ion exchanger are neutralised with alkali metal ions to no more than 15 % and that on supplying the nickel-containing aqueous solution to the ion exchanger said solution has a pH value in the range 2.5 to 6.0.