Abstract: Electrokinetics and flotation of diaspore in solutions of different alkylamine hydrochlorides (with 12,14 and 16 carbon atoms) were studied. The point of zero charge (PZC) of diaspore was determined by measuring zeta potential (streaming potential method) as a function of pH. Dodecyl, tetradecyl- and hexadecylamine hydrochloride ions seem to be strongly adsorbed on the interface because they make the zeta potential more positive as the concentration increases. The PZC of diaspore is determined at pH 5.7. Flotation of diaspore was studied and shown to be influenced by the chain length of collectors and both collector and hydrogen ion concentration. The optimal experimental flotation conditions as pH and concentrations agreed well with that predicted from solution chemistry calculations, and the floatability of diaspore is poor while the pH value of flotation system is too high or low. The results of calculation also predict a wide pH range of effective flotation with increasing collector concentration.

Key words:  flotation; alkyl amine; diaspore