Fundamental understanding of secondary processing aids in bitumen extraction from mined oil sands

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The water based bitumen extraction processes currently being used in the oil sand industry were mainly designed to process ores that are relatively high in bitumen content and low in fines content. However, there exist a large amount of low-grade high-fines ores which alone yield poor bitumen recovery. These poor ores need to be blended with a high proportion of high-grade, low-fines good ores to achieve desired extraction performance. In some mines, however, there are not enough good ores for blending. A solution is urgently needed to enable the processing of poor ores without or with limited ore blending. To this end, Syncrude Canada Ltd. developed a new technology that significantly improves bitumen recovery, especially for poor ores. The core of this patented technology is to use the synergy of sodium hydroxide (caustic) as the primary process aid (PPA) and a selected chemical as the Secondary Process Aid (SPA). It was found that the combined use of caustic and sodium citrate as SPA not only significantly improved both bitumen recovery and froth quality, but also increased bitumen production rate. This invention enables more bitumen to be recovered from the Alberta oil sands resources. It has been successfully implemented at Syncrude for a full scale commercialapplication. However, the fundamental science regarding why and how the SPA works in bitumen extraction remains to be investigated.This proposed research is to advance our fundamental understanding of secondary processing aid (SPA) in bitumen extraction. The proposed research program will provide the scientific leadership to the oil sands industry for the development of next generation of secondary processing aid to improve the bitumen extraction performance.