Non-aqueous extraction of Alberta oil sands is of great interest to developing an alternative to the current hot-water extraction process to eliminate the tailing ponds. Investigations have been conducted to evaluate the performance of solvent mixtures to extract bitumen from a high-grade oil sands ore. Solvent mixtures of cycloalkane and n-alkanes were studied on the basis of their Hildebrand solubility parameters, which affect bitumen recovery and fine solids migration during the extraction process, and the results were compared to single solvents. Cyclohexane, cyclopentane, and methylcyclopentane were selected as the cycloalkane solvents, and they were studied in combination with n-alkane solvents, such as n-heptane, n-hexane, or n-pentane, to make up a final solubility parameter between 16.65 and 16.45 MPa1/2 for the final solvent mixture. It was observed that the solubility parameter of the solvent mixture has more impact on the migration of fine solids in bitumen than the recovery of bitumen. The amount of fine solids migrating into the bitumen product followed the order of cycloalkane/n-heptane > cycloalkane/n-hexane > cycloalkane/n-pentane.

Solvent extraction of bitumen from the Alberta oil sands has the potential to overcome the shortcomings of the current aqueous extraction process by reducing fresh water demand and eliminating tailings ponds. Bitumen is recovered as a solution, leaving behind the solids (or gangue) with a residual solvent and water from the original ore. Removing the solvent from the gangue is a crucial step that involves evaporation of volatile material (cyclohexane) from a porous matrix in the presence of a less volatile immiscible phase (water). In this study, we examined the effects of relative humidity, temperature, and the addition of water during cyclohexane extraction on the extent of cyclohexane removal from the extraction gangue. The drying curves showed two constant‐rate periods, with the initial period mainly removing cyclohexane, and the second mainly removing water. The initial drying rate of gangue in an environmental chamber was 2.7 times faster than drying in a fume hood due to the stronger convective currents in the chamber produced by its fan. The initial drying rate was independent of the relative humidity, which was in the range of 30–90 %, but the residual cyclohexane content in the gangue increased at high relative humidity. The addition of water to oil sands prior to cyclohexane extraction increased the residual cyclohexane in the gangue, likely by forming a barrier to efficient evaporation.

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Solvent‐based extraction has the potential to give higher bitumen recovery from mined oil sands without further accumulation of tailings ponds. A crucial aspect of this technology is the recovery of solvent from the solid waste stream, or gangue. Experiments were performed on gangue after cyclohexane extraction from high‐ and low‐grade oil sand ores to determine the effects of drying temperatures from 25 to 105 °C and pressures from 30 to 95 kPa. Increasing temperature and decreasing pressure both increased the mass flux of evaporating cyclohexane. The maximum mass flux of cyclohexane correlated strongly with cyclohexane vapour pressure at the oven temperature. The total time required to reach a target residual cyclohexane concentration of 250 mg/kg followed a power law relationship with both temperature and pressure, ranging from 300 to 9000 s depending on oven temperature and pressure. Evaporation of solvent was slower from the gangue from low‐grade ore, with a total completion time 3.2 ± 0.9 (n = 33) times longer compared to gangue from high‐grade ore at the same temperature and pressure. The higher water and fines contents of the gangue from low‐grade ore likely contributed to this result.