Formation and Characterization of Clay Complexes with Bitumen from Athabasca Oil Sand

Eliza Czarnecka and J. E. Gillott
Department of Civil Engineering, The University of Calgary, Calgary, Alberta T2N 1N4, Canada

Abstract: Montmorillonite, kaolinite, illite, and chlorite were found to adsorb bitumen and its pentane-soluble and pentane-insoluble fractions. The formation of clay-bitumen complexes is influenced by the nature of the exchangeable cation on the clay and by the solvent carrier which stabilizes the bituminous compounds. Ca-clays adsorb organic compounds more strongly than sodium forms except in the presence of nitrobenzene. Solvents of high dielectric constant, such as nitrobenzene, promote ionization so that the ion-exchange mechanism of adsorption is favored, whereas solvents of lower dielectric constant, such as chloroform, tend to solvate rather than to dissociate bitumens. The behavior of the montmorillonite-bitumen complex in variable relative humidity indicates that organic molecules adsorb primarily on external surfaces and cause the clay to become less hydrophilic than prior to treatment. Clay-organic complexes are sufficiently stable to resist powerful organic solvents. The clay-organic complex separated from the Athabasca oil sand behaves similarly during chemical treatment to complexes formed between bitumen and the four reference clay minerals.

Key Words: Bitumen • Clay-organic complex • Infrared • Montmorillonite • Oil sand • X-ray powder diffraction

Clays and Clay Minerals; June 1980 v. 28; no. 3; p. 197-203; DOI: 10.1346/CCMN.1980.0280305
© 1980, The Clay Minerals Society
Clay Minerals Society (www.clays.org)