Journal of Chemical Technology and Biotechnology, Vol.60, No.4, 405-411, 1994
Dispersion Flocculation Studies on a Goethite-Clay System
Dispersion-flocculation studies on a Goethite-clay system using flocculants were carried out as a function of flocculant concentrations, pH of slurry, time of agitation and dispersant dosage. Also, the effects of pH and polymer concentrations on the adsorption behaviour of the system were investigated. Results show that well flocculated goethite was preferentially obtained from 4% goethite/kaolinite clay suspensions, with 50 ppm causticised starch in the slurry at pH values of 3-11.5 and with 50 ppm polyacrylamide at pH values of 3-8. Good flocs were also obtained on flocculation of the goethite suspension with 50 ppm polyacrylamide at pH values of 5-7, while the kaolinite suspension did not respond to the same dosage of causticised starch in the same pH range. Results further reveal that for the goethite/kaolinite suspension, the best result was obtained with 50 ppm polyacrylamide at pH values of 7-10. Based on the data generated in the study, it was concluded that causticised starch is a better flocculant than polyacrylamide for goethite suspensions although polyacrylamide is an excellent flocculant for kaolinite suspensions.