Process for treating contaminated cleaning solutions from printing and varnishing processes by means of cross-flow ultrafiltration and rotary filtration

摘要

Process for the treatment of cleaning solutions contaminated with paints, lacquers and similar products, as they occur in the production of the same and in printing and coating processes, wherein the contaminated solution is prepared in a multi-stage process consisting of sedimentation, ultrafiltration and spray drying such that the recovered solution, if necessary after caching, can be reused for its original purpose. In the first process step impurities are separated by sedimentation whose density is greater or less than that of the cleaning solution. In the second process step, the remaining impurities are separated by cross-flow ultrafiltration. In the third process step, the liquid residue of the ultrafiltration is converted by rotary filtration into a solid state. In this method, a recovery rate of cleaning solutions of more than 99% and a solids content of the residue of more than 60% is achieved.