WASTE-WATER-REDUCED PHOSPHATING METHOD BY REPROCESSING A SOLUTION FOR REMOVING FAT AND/OR RINSING WATER

摘要

The invention relates to a method for phosphating metal surfaces. The metal surfaces are cleaned according to an injection method and/or immersion method comprising the following steps a) cleaning by means of at least one cleaning solution, b) rinsing with at least one rinsing water after cleaning, c) phosphatation with a phosphating solution which contains 3 to 50 g/I phosphate ions, calculated as PO4<3->, 0,2 to 3 g/I zinc ions, optionally, additional metal ions and, optionally, accelerators d) rinsing with at least one second rinsing water after phosphation, and e) withdrawing, in a continuous or discontinuous manner, at least one part of the cleaning solution and/or one part of the first rinsing water, introducing it into an intermediate container and subjecting it to ultrafiltration, in order to obtain a first retentate and a first permeate. The invention is characterised in that f1) the first permeate is at least partially evaporated and/or f2) the first permeate is at least partially subjected to reverse osmosis, enabling a second retentate and a second permeate to be obtained. The second retentate is, preferably, fractionated or completely evaporated. Reusable materials are recovered.