Circular 90—A correlation between surface phenomena and flotation in silicates

By R. A. Deju and R. B. Bhappu, 1967, 22 pp., 4 tables, 15 figs.

Experimental studies on the flotation of silicate minerals go back at least 30 or 40 years. These investigations for the most part have been empirical and have failed to give detailed information on the nature of the silicate-solution interface. Also, very little has been reported about the sorptive properties of silicate minerals in the presence of various collector systems. Deju and Bhappu have made a theoretical and experimental study of the sorptive properties of representative silicate minerals in an aqueous solution. The present study extends the previous work to include the surface phenomena occurring in a silicate-sulfonate system and in a silicate-amine system. Efforts were made to correlate the surface sorption in the presence of a sulfonate or an amine to the surface sorption in the presence of only deionized water. The term sorption rather than adsorption is used because both ion exchange and physical adsorption play important roles in the surface phenomena occurring in solid-liquid systems. Experiments were also conducted varying the collector concentration to examine its effect both on the total surface sorption and the rate of sorption. These experimental results are compared to a theoretical model based on a Langmuir-type sorption isotherm. Finally, the behavior of some silicate minerals in flotation was predicted from these sorption studies and an explanation for the flotation of silicate minerals was postulated on the basis both of theoretical predictions and experimental results.