The surface properties and flotation behaviour of aluminosilicates including kaolinite, illite and pyrophyllite, using N-(3-aminopropyl)-dodecanamide as a collector, have been investigated. The best recoveries of kaolinite, illite and pyrophyllite were respectively 91.5%, 90.6%, and 96.3%. On the basis of FT-IR spectra and zeta potential, the ionization of surface hydroxyl, as well as isomorphic exchange of surface ions, accounts for the mineral surface charges. The mechanisms of interactions of the mineral surface with collectors depend on the pH of the pulp. In the acidic region, the interactions of the mineral surfaces with the collector were mainly electrostatic, but in the alkaline region, the interactions are mainly due to hydrogen bonding. It can be seen from SEM photographs of aluminosilicates that pyrophyllite takes the shape of thin slices, but kaolinite and illite have irregular porous structures. Specific surface area and particle size distributions of aluminosilicates also indicate that kaolinite and illite are relatively large porous particles with larger external as well as internal surface areas. (C) 2003 Elsevier Ltd. All rights reserved.