Clay minerals in nonaqueous extraction of bitumen from Alberta oil sands: Part 1. Nonaqueous extraction procedure

A non-aqueous bitumen extraction process was studied where only toluene and heptane, with no water additions, were used to extract bitumen from two Alberta oil sands ore samples. One sample had a high bitumen (13.5 wt.%) and low fines (5.3 wt.% < 45 μm) contents, while the other sample had an intermediate bitumen (10.5 wt.%) and high fines (23.3 wt.%) contents. Bitumen recovery and product quality were measured under different process conditions such as the ratio of toluene to heptane and settling time. The Dean Stark procedure was used to determine the solids, bitumen and water contents of the extraction products. In addition, the water content was determined by the Karl Fischer titration method. High bitumen recovery was obtained for both oil sands ore samples although the high fines ore sample was more sensitive to the extraction conditions, especially the toluene to heptane ratio. A product with high purity, containing more than 99.5 wt.% bitumen on a solvent-free basis, was produced at room temperature under the optimum extraction conditions tested. The optimum settling time to achieve a pure product was less than 10 min, based on solids and water contents in the supernatant.