Application of coagulants in paint and varnish factories
The main pollutants of wastewater are residues of paintwork materials, including film-forming polymeric resins, lacquers, enamels, paint pigments, fillers, plasticizers, solvents and other auxiliary materials. Effluents from the production of synthetic resin varnish are cleaned by flotation or sedimentation using a coagulant together with flocculant. This allows to eliminate 88 to 99% of suspended solids. Coagulants are also used to purify pigment production containing fine suspended titanium dioxide, iron oxide, lithopone, ultramarine, etc. Its use in combination with flocculant provides 2.5-fold improvement of fluid quality and decreased sedimentation.