Surface Chemistry of Radionuclide-Mineral Interactions

Abstract

Surface chemical changes of the feldspars labradorite and microcline, after hydrothermal reaction in saline solution, have been studied using spectroscopic techniques. The interaction of cesium ions with the feldspar surfaces, both before and after hydrothermal alteration, has been followed, and the nature of reactions between the mineral surfaces and the cesium ions has been examined. In saline solution, all of the feldspar surfaces were shown to alter to a smectictic-clay layer. In the hydrothermal reaction between the feldspars and cesium, a secondary cesium aluminosilicate species, pollucite (CsA1Si20 6 ) was formed. Under ambient conditions, cesium was poorly sorbed onto unaltered feldspar surfaces, but more strongly onto altered ones,