Sorption of Uranium and Radium by Biotite, Muscovite, and Phlogopite

Lloyd L. Ames, Jeffery E. McGarrah and Becky A. Walker
Battelle, Pacific Northwest Laboratories, P.O. Box 999, Richland, Washington 99352

Abstract: The sorption of U and Ra on finely ground biotite, muscovite, and phlogopite was adequately described by the Freundlich adsorption equation, (x/m) = KCn, at low U and Ra concentrations despite Ra precipitation at the higher temperature. Radium and U sorption-efficiency curves derived from the Freundlich constants generally showed decreased distribution coefficients in response to increasing temperature and increasing Ra or U concentrations. Temperatures investigated were 5°C, 25°C, and 65°C. Solution compositions used were 0.1 M NaCl and 0.01 M NaHCO3 for U, and 0.01 M NaCl for Ra. Uranium initial solution concentrations ranged from 1.00 × 10−4 M to 4.00 × 10−7 M; the Ra initial solution concentration range was 6.80 × 10−7 M to 8.60 × 10−9 M.

In 0.01 M NaHCO3 solutions, anionic uranyl carbonate complexes were prevalent, and because they are weakly sorbed relative to free uranyl ion and uranyl hydroxy complexes, the result was a relatively low U sorption efficiency on biotite and phlogopite and excellent sorption efficiency on muscovite. Uranyl carbonate complexes decreased in solubility with increasing temperature, so that U sorption efficiency on biotite increased with increasing temperature. Sorption of uranyl ion and uranyl hydroxy cations on biotite decreased with incresaing temperature.

Key Words: Anion exchange • Biotite • Cation exchange • Muscovite • Phlogopite • Radium • Sorption • Uranium

Clays and Clay Minerals; October 1983 v. 31; no. 5; p. 343-351; DOI: 10.1346/CCMN.1983.0310503
© 1983, The Clay Minerals Society
Clay Minerals Society (www.clays.org)