Abstract: The floatability of three minerals is in the sequence of barite＞celestite＞ gypsum in sodium oleate and salicylhydroxamic acid system and of gypsum＞celestite＞ barite in lauryl amine system. XPS and infrared spectrum analysis were used in studying the functional mechanism between collectors and minerals. The function between sodium oleate and the three sulfate minerals is found to be chemical adsorption; that of lauryl amine, physical adsorption; and that of salicylhydroxamic acid, chelating reaction. The theoretic calculation for the chemical bonds of mineral crystal structure indicate that the Mⁿ⁺-O^2- breakage degree in the crystal structure of these three minerals is closely related to mineral floatability.

Key words: Sulfate minerals, Flotation, Crystal chemistry