<寄書>浮選法に於ける界面電位の意義について

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In aqueous solutions with substantial conductivity, such as the pulp solutions encountered in flotation, electrostatic charges are almost impossible. But air bubbles and mineral particles can be charged in pure water or in aqueous solutions. These charges may be ionic rather than electrostatic. The validity of electrostatic theory in flotation hitherto proposed is very unreliable from the above viewpoint.The ζ-potential of air bubbles and mineral particles was measured by the cataphoretic method. The sign and the absolute value of ζ-potential have no serious effect on the attachment of air bubbles and mineral paricles, so to speak, electrical forces such as repulsion or attraction are not responsible for air-mineral contacts. The electrical surface energy is represented as follows : [numerical formula] The electrical surface energy of a comparatively flat surface can be calculated by this equation. In the case of aqueous solution, dE=0.0129 dyne/cm (C=1×10^<-4> mol/l, T=291°K, ζ=90mV). Therefore, it may be recognized that an electric charge has no serious effect on the change of the wettability of mineral particles. Gaudin and Sun have proposed the Zeta Coefficient to explain the variation of floatability of mineral particles, but this coefficient does not always hold reasonable relationship with the variation of floatability. The author has derived the theoretical relationship between ζ-potential and floatability from the viewpoint of adsorption : [numerical formula] And, in the case of quartz, the above equation can be simplified as follows : [numerical formula] It is proved that these eguations can indicate the variation of floatability of mineral particles and that author's theory is theoretically inclusive of Gaudin and Sun's. Floatability of minerals is influenced not only by ζ-potential but also by the kind of ions. Therefore, we cannot anticipate the change of floatability of minerals only from ζ-potential data. In the case of mineral particles in the solutions of univalent ion, it is shown that the variation of ε-potential and ζ-potential agrees well with the Stern's theory of the electrical double layer, but this is not true in aqueous solutions of bivalent and trivalent ions. Although the theoretical consideration has not been accomplished, both ε-and ζ-potentials seem to have the same role in the consideration of the bubble-mineral contacts.
東北大学の論文
1953-09-10

著者

城温三
山口大學工學部鑛山學教室

<寄書>浮選法に於ける界面電位の意義について

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