ABSTRACT
The major groups of anionic surfactants used as collectors are the carboxylates, sulfates, sulfonates, phosphates, phosphonates, and hydroxamates. These ionic surfactants have common characteristics. They are prone to dissociation, ionization, and hydrolysis, the extent of which depends on the pH of the aqueous environment. Collector adsorption at the mineral surface may involve physical or chemical forces or both. The key to optimizing the selectivity of sulfide or nonsulfide mineral flotation is usually through controlled surface modifications of the economic or gangue minerals. For nonsulfide mineral flotation in particular, where both physical and chemisorption can be the mode of collector adsorption at the mineral surface, surface chemical properties of the mineral play an important role. The inorganic electrolytes common in the anionic flotation of nonsulfide minerals include sodium silicates, polyphosphates, and hydrogen fluoride. There are various simple organic compounds, such as citric acid, tartaric acid, and oxalic acid, which are quite often used as modifying agents in nonsulfide mineral flotation systems.
