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Effects of Sodium Citrate on Slime Coatings in Bitumen Extraction
- Author / Creator
- Zhang, Dingfang
Albertan oil sands ores are becoming more difficult to process efficiently as the clay content of the ore increases and the grade of the ore worsens. A key to improving the extraction of bitumen from low-grade oil sands, thereby increasing the longevity of this critical resource, is reducing the formation of slime coating. Slime coating, which refers to the coverage of fine particles on the surface of bitumen droplets, can have a significant impact on the performance of flotation and hence on bitumen extraction recovery from oil sand ores.
Recently, addition of sodium citrate during the alkaline hot-water extraction process was shown to improve bitumen recovery and froth quality. Along with increased bitumen extraction efficiency, the addition of sodium citrate generated considerable environmental benefits, including less bitumen contained in tailings, more efficient water usage, and reduced energy intensity involved in the separation process.
The objective of the current study was to advance the fundamental understanding of the role sodium citrate has on reducing bitumen slime coating in the aeration stage of oil sands processing. Methods employed were zeta potential distribution measurements using Zetaphoremeter, the measurements of interactions between bitumen and clay particles using QCM-D in various model electrolyte solutions, and the analysis of calcium adsorption on montmorillonite particles using inductively coupled plasma (ICP) analysis. It was shown that sodium citrate can prevent slime coating from occurring, but sodium citrate cannot remove slime coating once it has occurred. Therefore, the addition of sodium citrate at the beginning of the bitumen extraction process can lead to a more efficient and environmentally-friendly processing of a valuable energy resource.
- Graduation date
- Spring 2020
- Type of Item
- Master of Science
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