Abstract
In current mine-based operations in the oil sands of northern Alberta, the production of a given volume of bitumen generates the equivalent volume of mature fine tailings (MFT), a mixture of water, fines, and residual organics. The clay mineralogy of the oil sand is thought to have a major influence on settling behaviour of MFT. In order to develop methods of handling the growing problem of oil sands tailings containment and reclamation, it is critical to understand the nature and role of the fine suspended clay particles.
Most studies have identified the major clay minerals in the oil sands to be kaolinite and illite. The reported bulk surface area is far larger, however, than would be possible through contributions from kaolinite and illite alone. More recent x-ray diffraction studies have reported a low degree of interstratified smectite in kaolinite and illite to account for the observed surface area. The present work applies transmission electron microscopy lattice fringe imaging, and electron diffraction to evaluate the fundamental particle size of the clay minerals. Our investigations show that the mean fundamental particle thicknesses of kaolinite and illite in the minus 2-μm fraction are less than 10nm, which would explain the large surface areas reported in the literature.
