Role of macromolecules in kaolinite flotation

Flotation tests show that the floatability of kaolinite is much better in an acidic than in an alkaline medium containing cationic collectors. The (001) basal planes of kaolinite are found to adsorb cationic collectors favorably, which render the surface hydrophobic. The (00 (1) over bar) planes interact with macromolecules carrying groups containing -O-, -N-, and/or -F- of high electronegativity, and the resultant flocculation minimizes the exposure of hydrophilic (00 (1) over bar) planes. As a result, the cationic flotation of kaolinite is enhanced by the addition of these types of macromolecules. The zeta potential measurement and macromolecule adsorption study indicate that the adsorption of anionic PAM on kaolinite is dominated mainly by hydrogen bonding interactions. (C) 2004 Elsevier Ltd. All rights reserved.