layer silicates preferably from the group of montmorillonites bentonites hectorites or kaolins c ethylene acrylic acid copolymers which contain 8 to 25 by weight of acrylic acid units and 92 to 75 by weight of ethylene units based on the acid form of the copolymer and which are present as the salt of an inorganic or organic base preferably in the form of an aqueous concentrate g water soluble alkali metal and or ammonium salts of molybdic acid and or isopolymolybdic acid and h polyelectrolytes based on quaternary methacrylates for example those of the rohafloc u00ae series rohm gmbh in another preferred embodiment of the invention the coagulants mentioned above additionally contain at least one of the following components i to k i a compound from the group consisting of cyanamide dicyanodiamide or cyanamide salts preferably dicyanodiamide k active substances and or auxiliaries typical of paint coagulants preferably biocides ph regulators corrosion inhibitors antifoam agents or solubilizers the production of the paint coagulants from the individual components is familiar to the expert from the prior art the coagulants are introduced either continuously by means of suitable optionally automatable metering systems or discontinuously for example once a day the coagulants are added to the circuit water in a quantity of 0 5.