Preparation and Handling of Dithionite-Reduced Smectite Suspensions

Joseph W. Stucki1, D. C. Golden1 and Charles B. Roth2
1 Department of Agronomy, University of Illinois, Urbana, Illinois 61801
2 Department of Agronomy, Purdue University, West Lafayette, Indiana 47901

Abstract: Using Garfield, Washington, nontronite as the model mineral system, methods and apparatus were developed to prepare reduced suspensions in citrate-bicarbonate-dithionite (CBD) solution. These techniques were effective in removing excess, undesired solutes from reduced suspensions while maintaining a high Fe2+ content. They also enabled the preparation of dried, reduced films preferentially oriented with respect to the crystallographic c-axis. Supernatant solutions were collected and analyzed for Fe, Al, and Si, from which the extent of dissolution of the clay as a result of CBD treatment was assessed. Results indicated that very little Fe and Si were released to solution, but as much as about 8% of the total Al was solubilized. The highest levels of Al in solution Were observed in CB treatments without dithionite.

Key Words: Dithionite • Iron • Nontronite • Reduction • Reoxidation • Smectite

Clays and Clay Minerals; June 1984 v. 32; no. 3; p. 191-197; DOI: 10.1346/CCMN.1984.0320306
© 1984, The Clay Minerals Society
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