Release Rate of Potassium and Structural Cations from Micas to Ion Exchangers in Dilute Solutions

Abstract

Abstract The rate of release of K and structural cations from three micas (biotite, phlogopite, and muscovite) was measured in two‐particle size ranges (5 – 20µm and 20 – 50µm), in dilute electrolyte solutions (0.001 N ), and at pH 3.0 and 7.0. The rate of K release from phlogopite and biotite was similar to the rate of release of structural cations under acidic conditions and significantly higher under neutral conditions. These findings indicate that structural decomposition of phlogopite and biotite is dominant in acidic conditions, and that the role of interdiffusion increases in neutral conditions. Decomposition was more sensitive than interdiffusion to particle size. The rate of K‐release from muscovite was about 5 and 15% that from biotite and phlogopite, respectively. The rate of K release from muscovite was higher than the rate of Al release. This indicates that muscovite is the most stable of the three micas and that the decomposition mechanism for K‐release in muscovite was less important.