Composition dependence of cyclohexane‐extracted gangue drying at ambient conditions

Abstract

The drying of residue cyclohexane in a series of reconstituted gangue samples at ambient conditions was studied. The reconstituted gangue samples contained controlled amounts of residual bitumen, water, and fines (solid particles <45 μm). Regardless of the gangue composition, the initial drying flux was constant, and more than 90% of the residual cyclohexane was removed in this stage. The initial drying was driven by the liquid film flow induced by the differences in liquid film's radii of curvature along the pore channels. The liquid was a diluted bitumen solution that was transported to the surface, where cyclohexane evaporated with a rate comparable to that of pure cyclohexane evaporation. Upon the solvent evaporation, the dissolved bitumen was deposited on the sample surface. The residual bitumen content exerted an adverse effect on the initial drying flux because the dissolved bitumen significantly increased the solution viscosity, thereby reducing the liquid film flow rate.There existed an optimum water content range (3.9-6.0 wt%) that facilitated the formation of bitumen solution film in the pores, favouring drying. When there was a high concentration of water or no water, the initial drying flux was decreased remarkably. The initial drying flux was insensitive to the fines content. Adding fines may have two counteracting effects on the drying process.Fines decreased the mean pore size, thereby lowering the liquid film flow rate. However, the hydrophobicity of the pore surfaces was increased as fines are usually covered by asphaltenes. This favours liquid film formation.

Microwave-Assisted Removal of Cyclohexane from Oil Sands Gangue

“…A rich oil sands ore sample provided by Syncrude Canada Ltd. was used. The ore sample was extracted using cyclohexane (purity 99.0%, certified ACS grade, Fischer Scientific, United States) in a Dean–Stark extraction apparatus . The solvent was condensed in the trap and allowed to overflow back over the sample placed in a thimble, to dissolve and to extract the bitumen.…”

“…In our previous work, we have demonstrated that cyclohexane is probably the most ideal organic solvent to be used for the nonaqueous extraction of bitumen. − Also, we have showed how the key gangue compositions affect the effectiveness of removing cyclohexane by an air-drying method under ambient conditions. , The major advantage and drawback of the air-drying method are minimal energy required and being slow, respectively. The process is slow because liquid cyclohexane in the gangue first flows upward due to capillary pressure to the gangue surface before it vaporizes.…”