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The transformation of high molecular weight components present in heavy oils into useable liquid fuels requires their decomposition by means of a variety of processes. The low molecular weight species produced recombine under controlled conditions to generate synthetic fuels. However, an important fraction undergo further recombination into higher molecular weight components, leading to the formation of coke. The optical texture of the coke can be related to its originating components. Those with high sulfur and oxygen content tend to produce cokes with small optical texture or fine mosaic, whereas compounds with relatively high hydrogen content are likely to produce large optical texture or domains. In addition, the structure of the parent chemical components, planar or nonplanar, determines the isotropic or anisotropic character of the coke. Planar molecules have a tendency to align in an approximately parallel arrangement to initiate the formation of the nematic mesophase leading to the formation of anisotropic coke. Nonplanar highly alkylated compounds and/or those rich in polar groups form isotropic coke. The aliphatic branches produce steric hindrance to alignment, whereas the polar groups participate in cross-linking reactions.

Froth quality is determined by the water and solids content in the extracted froth. Decreasing the water and solids in the froth minimizes the need for their removal in the downstream processes. The quality of froth is related to the formation mechanism and thus the physical structure of air bubbles, bitumen, water, and solids in the froth layer. Understanding the interactions between these components in the froth layer will lead to improved froth handling technologies. A cryogenic sampling method was devised at CANMET's Western Research Centre and was successfully tested at Syncrude's pilot plant. Samples for microscopic observations were collected from the primary separation vessel which was operated at 80°C (Clark and OSLO processes) and at 30°C and 10°C (OSLO process). The results were used to develop a froth structure model.

Improved froth handling technologies in primary and secondary oil sands flotation are important, especially as new extraction technologies for future projects may require the operation to be carried out at lower temperatures. One approach to reducing the ratio of solids or minerals to bitumen in "dirty" froth is by intimately contacting or washing it with clean water. The solids may be either oil-wet, water-wet, or bi-wet; their partitioning in the flotation vessel is determined by their wettability. In addition, the water chemistry can be studied by 180 and 2H isotopes to determine whether the water found in oil emulsions during various processing stages originates from the oil sands feed, the conditioning step, or the flood water addition and subsequent froth handling. Froth washing results indicated that a small amount of solids (-8%) remained in the froth. The solids wettability may be probed by direct microscopy or calorimetry. Finally, the preliminary isotope study shows promising results in determining the origin of the water in oil sands processing emulsions.