A Century Of Unraveling The Chemistry Of Flotation

Some historical sketches of the early development of froth flotation are presented. Flotation technology involves several aspects: chemical control of mineral hydrophobicity, selectivity in flotation, flotation kinetics, flotation machines, and process optimization and control. However, only some aspects of the regulation of mineral flotability by the addition of chemical collectors in some selected cases are discussed. The early contributions to flotation science by Langmuir, Gaudin, Wark, and Taggart are briefly outlined. With a firmer understanding of surface chemistry, electrochemistry, and the electrical double layer, progress has been made in understanding the fundamentals of flotation chemistry, although sound theoretical underpinnings still are needed in these very complex systems. Flotation chemistry is related very directly to the type of mineral being floated since the systems depend strongly on the chemical and physical characteristics of the minerals. Full discussion of chemical reagent phenomena would be in terms of the behavior of naturally flotable minerals, sulfides, oxides, silicates and alumino-silicates, and salt-type minerals. At this time, citing a few cases involving salt-type minerals and oxides, the dependence of their flotation surface chemistry will be discussed in terms of the role of adsorption, surface reaction, and the hydrophobic effect.