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Ion Selectivity of Micas as Influenced by Degree of Potassium Depletion
Author(s) -
Le Roux J.,
Rich C. I.
Publication year - 1969
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1969.03615995003300050020x
Subject(s) - mica , muscovite , vermiculite , potassium , selectivity , ion , biotite , chemistry , mineralogy , analytical chemistry (journal) , inorganic chemistry , materials science , quartz , chromatography , metallurgy , biochemistry , organic chemistry , composite material , catalysis
The Rb/Sr selectivity coefficient of muscovite and biotite reached a maximum at an intermediate degree of K‐depletion of these micas. The Rb/Sr ratio of ions absorbed from a solution, initially containing equivalent amounts of Rb and Sr, was determined for the two micas altered to different degrees to Mg‐vermiculite. X‐ray diffraction of the Rb‐Sr treated vermiculites gave nonintegral peaks for the basal reflections, indicating random interstratification of Rb and Sr + Mg saturated layers. The results support previous proposals that selective sites for K are probably situated at wedge‐shaped zones occurring at frayed edges and deeper within the altered mica particles. As K is removed from mica, the number of such wedges should first increase and then decrease. Selectivity of K and other large monovalent ions should also follow this same trend.