Effect of Comminution on the Cation-Exchange Capacity of Talc and Chlorite from Trimouns, France
J. Yvon, J. M. Cases, R. Mercier, J. F. Delon, 1985. "Effect of Comminution on the Cation-Exchange Capacity of Talc and Chlorite from Trimouns, France", Proceedings of the International Clay Conference Denver, 1985, Leonard G. Schultz, H. van Olphen, Frederick A. Mumpton
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From an analysis of cation-exchange capacity (CEC), surface area, and structural data of talc-chlorite mixtures from Trimouns, France, ground in various manners, the talc component appears to have surface properties that can be predicted from its ideal structure. The CEC of 0.15 to 0.35 meq/100 g results only from the dissociation of silanol groups on lateral surfaces. The experimental equivalent size of an exchangeable site is 15 ± 8 Å compared with the theoretical value of 19.5 Å.
The CEC of the chlorite component, ranging from 7 to 10 meq/100 g, has three different origins: (1) structural CEC of about 5.8 meq/100 g; (2) CEC resulting from Si-OH and IVAl-OH dissociation on lateral surfaces, where the equivalent size of an exchange site is 29.5 Å2; and CEC resulting from hydroxide-sheet leaching. Estimates show that half of the Mg is leached from a basal face if it consists of a hydroxide sheet and that the contribution of Mg leaching from lateral surfaces leads to a CEC three times that of the tetrahedral border CEC These results suggest that the surface properties of chlorite cannot be understood if the mineral is assumed to be stable and in electrostatic equilibrium.
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Proceedings of the International Clay Conference Denver, 1985
The papers included in this proceedings volume are representative of the research on clays being conducted in all parts of the world at the time of publication. Many of the subjects treated are controversial, and although some ideas expressed may not necessarily represent the views of the editors, the referees, or the publisher, they deserve to be brought to the attention of the international clay community.