POLYMER DOSE EFFECTS ON FILTRATION FOLLOWED BY EXPRESSION OF CLAY SLURRIES

Filtration followed by expression characteristics of cationic polymer conditioned clay slurries are reported for the first time in this work . As the polymer dosage increases, the resistance to filtration greatl y decreases until a specific dose has been reached, where the zeta pot ential is close to zero. And further increase in polymer dose converse ly raises the resistance. The expression data are interpreted by the T erzaghi-Voigt combined model, from which the model parameters are eval uated. The polymer conditioning has only a mild effect on the primary consolidation process but has, however, a considerable influence on se condary consolidation characteristics. When zeta potential changes fro m negative to positive, both the easiness of creeping of constituent p articles within the sludge cake and the fraction of moisture removal b y the secondary consolidation attain a maximum., The optimal polymer d ose criterion considering the filtration and expression stages separat ely, or in combination, is (sic). (C) 1997 Academic Press