Energy & Fuels, Vol.32, No.7, 7451-7457, 2018
Probing Bitumen Liberation by a Quartz Crystal Microbalance with Dissipation
The detachment of bitumen from sand grains in oil sands processing is known as bitumen liberation. In this study, a quartz crystal microbalance with dissipation (QCM-D) was applied to study the bitumen liberation process under various process conditions. Bitumen was coated on the surface of silica sensors to simulate the oil sands ore. By recording the change of frequency and dissipation of the coated sensor, QCM-D allows for a real-time quantitative analysis of the bitumen detachment process. The effects of solid wettability, solution pH, and operation temperature on bitumen liberation were investigated using QCM-D. The effects of different solution pH values and temperatures on bitumen liberation were conducted with untreated hydrophilic silica sensors. It was found that the degree of bitumen liberation (DBL) was improved from 32 to 98% when the solution pH was increased from 7.8 to 11, indicating the importance of solution pH in the water-based bitumen extraction process. An increasing temperature enhanced not only the degree of bitumen liberation but also the rate of bitumen detachment. The DBL from a hydrophobic silica surface was about 1.2% at pH 11.5 and 22 degrees C, which is much lower than the hydrophilic silica surface. QCM-D is a powerful tool in studying the bitumen liberation from both hydrophobic and hydrophilic surfaces.