Role of mineral flotation technology in improving bitumen extraction from mined Athabasca oil sands III. Next generation of water‐based oil sands extraction

Abstract

AbstractCurrent water‐based oil sands extraction operations are unsustainable, due to their consumption of large quantities of water and energy, generation of large volumes of fluid fine tailings, and rapid expansion of tailing ponds. From a brief analysis of the historical evolution of water‐based oil sands extraction, it has been identified that the use of conventional dispersed air flotation to recover liberated bitumen from oil sand slurries is mainly responsible for the high consumption of water required and the fluid fine tailings generated. Based on mineral flotation principles, a new concept is proposed, whereby water‐based oil sands extraction is simplified as a process of transferring hydrophobic bitumen from hydrophilic surfaces (sands) to hydrophobic surfaces (bitumen carriers). Compared to existing bitumen extraction technologies, bitumen liberation from sands is accelerated by attrition/scrubbing, and the liberated bitumen is recovered from the oil sand slurry by hydrophobic coagulation and heavy media separation. This concept is verified from preliminary laboratory tests for processing (above) average grade oil sands. The water required is significantly reduced from 100 to 150 wt% of the ores processed (as seen in current commercial operations) to 30‐40 wt% of the ores. Virtually no fluid fine tailings are generated, with the potential of eliminating tailing ponds. The tailings produced after bitumen extraction are paste‐like, containing >60 wt% solids, which can be directly disposed of in the mining pit, with little or no further treatment. Future research is needed to justify and refine the concept in large‐scale tests and engineer it into commercial operations.