VERFAHREN ZUR ENTSCHLAMMUNG VON PHOSPHATIERUNGSBAEDERN UND VORRICHTUNG FUER DIESES VERFAHREN.

摘要

Phosphating baths are treated to prevent the formation of iron phosphate mud by continuously drawing off a part of the bath and feeding it to a device having an oxidn. chamber where oxygen is introduced to produce iron phosphate, a mud conditioning chamber where the suspension is stirred and a sedimentation chamber where the mud is sepd. from the phosphate soln. which is then returned to the bath. 10-30 Vol.% of the bath is treated in a continuous fashion. The three chambers in the treatment device have a volume ratio of 1:0.5:10 to 1:1:1 pref. 1:0.5:5. The oxygen is added to the oxidn. chamber using a gasing unit made of a sintered polypropylene tubing of average pore size 0.1-5.0 micro-m, pref. 0.12-0.30 micro-m. The gas is O2, air or O2 enriched air which ensures an O2 feed of 0.01-100 mol O2 per hr. The stirring speed in the conditioning chamber is 100-300 rotations/min.