Coagulation and flocculation characteristics of talc by different flocculants in the presence of cations

The coagulation and flocculation characteristics of talc, using anionic, cationic and non-ionic flocculants in distilled and fresh water containing Ca2+, Mg2+, Na+. and K+ ions were investigated. It was shown that the stability of the talc suspension remained almost constant in distilled water at all pH values, while it was strongly coagulated with these cations at pH values greater than 10.5. In fresh water, anionic and non-ionic flocculants were very effective on the talc suspensions at pH 7.2 and at pH values greater than 10.5. Flocculation of the talc suspension was assisted by the coagulation effect at pH levels greater than 10.5. The cationic flocculant was ineffective on the talc suspensions in the presence of cations at almost all pH levels. However, the cationic flocculant caused weak aggregation of the suspension with distilled water in acidic conditions. (C) 2003 Elsevier Science Ltd. All rights reserved.