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

目前油砂工业中采用的水基提沥青工艺主要是为了处理沥青含量较高、细粒含量较低的矿石。但存在大量低品位高细粒矿石，单独开采沥青回收率较差。这些差矿石需要与高比例的高品位、低细度的好矿石混合，以达到理想的萃取性能。然而，在一些矿山中，没有足够的优质矿石用于混合。迫切需要一种解决办法，使贫矿石的加工不需要或限制矿石混合。为此，加拿大辛克鲁德有限公司开发了一种新技术，可以显著提高沥青的采收率，特别是对于劣质矿石。这项专利技术的核心是利用氢氧化钠（苛性钠）作为一级工艺助剂（PPA）和选定的化学品作为二级工艺助剂（SPA）的协同作用。结果表明，烧碱与柠檬酸钠复合使用不仅能显著提高沥青的回收率和泡沫质量，还能提高沥青的产量。这项发明可以从阿尔伯塔省的油砂资源中回收更多的沥青。该系统已成功在Syncrude进行了全面的商业应用。然而，关于SPA为何以及如何在沥青提取中起作用的基础科学仍有待研究。本研究旨在增进我们对沥青提取中二次加工助剂的基本认识。拟议的研究计划将为油砂行业提供科学领导，以开发下一代二次加工助剂，以提高沥青的提取性能。

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.