Robust Aqueous–Nonaqueous Hybrid Process for Bitumen Extraction from Mineable Athabasca Oil Sands

Mining and processing of Athabasca oil sands in Alberta, Canada, is a great success story of government–industry collaboration, fulfilling increased domestic and worldwide demands for oil. However, economic and environmental incentives still exist in the oil sands industry to enhance oil recovery and reduce energy consumption and water use, while minimizing green-house gas emissions and tailings ponds. The current industrial bitumen extraction processes, after surface mining, are exclusively water-based and operate at elevated temperatures, typically between 45 and 50 °C. Robust low-temperature processes, with reduced in-take of feedwater, that are less sensitive to ore characteristics are in a strong demand from both environmental and economical point of views. In response to this demand, we propose a robust aqueous–nonaqueous hybrid bitumen extraction process, in which diluent such as kerosene and naphtha is added to the oil sands prior to oil sands slurry preparation to decrease bitumen viscosity and enhance bitumen liberation. With the proposed hybrid bitumen extraction process, the oil sand processing temperature can be reduced to ambient temperature. To prove this concept, bitumen recovery tests were carried out on four Athabasca oil sand ores of good to poor processability, using a Denver flotation cell operated at ambient temperature. Adding kerosene or naphtha to oil sands at 4–11 wt % of the bitumen content was found to significantly enhance flotation recovery of bitumen and bitumen froth quality, especially for poor processing ores. It was found that kerosene addition not only increased bitumen liberation kinetics determined using our novel in situ bitumen liberation visualization flow cell (BLVFC) but also improved bitumen aeration measured by induction time apparatus.