Flocculants: The finest particles firmly fixedUltra-finely dispersed solids may still be present in water, even if the solution appears transparent to the naked eye. These solids must be removed from the water if surface water, for instance, is to be used for preparation of drinking water. Purely mechanical filtration is not capable of cleaning such colloidally dispersed solutions, containing particle sizes just below the level of microscopic visibility. These suspended impurities must be agglomerated to form larger filterable flakes before they can be removed from the water. This process is referred to as flocculation.
Due to their like electrical charge, the finely dispersed suspended particles do not agglomerate to form larger flakes, but instead mutually repel each other. The coagulation of the suspended impurities has to be artificially induced. Sachtleben Wasserchemie flocculants eliminate the electrical charges of the colloidally dispersed solids either partially or completely. The repellent forces between the suspended particles are reduced; micro-flakes are formed. Visible macro-flakes, which can be removed from the water by means of filtration, are then produced as a result of chemical reactions on the surface. (Primary) flocculants based on polyaluminium chlorides (PACs) are able to initiate flocculation directly, whereas flocculation aids are capable of agglomerating suspended matter from the water only in combination with a flocculant.
We use polyaluminium-chloride-based primary flocculants not only for cleaning of polluted water, however. Our broad range of Sachtoklar-, Sachtopur- and Ekozid- range flocculants assists in optimally fixing anionic trash in the papermaking process and provide excellent effectiveness and cost-efficiency. Paper-PAC-N is used effectively for the fixing of coatings and starch, as a retention agent and for improvement of screen dewatering processes. This contributes to the achievement of significantly improved paper strength, thus enhancing machine productivity.