@mastersthesis {40073,
	title = {The role of ultrafine particles in oil sands fine tailings reduction},
	volume = {Chemical Engineering},
	year = {1995},
	pages = {160},
	address = {University of Ottawa},
	abstract = {Fine tailings exhibit extremely poor dewatering characteristics. The research presented here deals with two closely related projects. The first project concentrated on finding an efficient treatment method for already existing fine tailings. The second project was to evaluate process modifications aimed at fine tailings reduction and to develop an understanding of the effect of electrolyte in the process water of the characteristics of fine tailings. The behavior of ultrafines separated from fine tailings was further investigated. A $\sp2$H NMR technique was applied to determine the gelation rates for ultrafines at different electrolyte concentrations. The gelation concentration was determined using ultrafines suspensions diluted with salt solutions. Results indicate, that while gelation time varies from minutes to weeks, the gelation concentration is always about 3-4 wt\%, even at an extremely high salt concentrations further floc densification (dewatering) is impossible. Although adequate floc densification could not be achieved using chemical treatment, dewatering was increased markedly using freeze-thaw (a physical method). To evaluate process modifications, samples of different process streams produced during comparison pilot plant runs performed at Syncrude Canada Ltd. were investigated. The aggregation state and distribution of ultrafines were determined in all stream samples. In conjunction with the characteristics of parent oil sand ores, results prove that the settling rate was different only up to the point where the gelation onset concentration of the ultrafines fraction was reached, regardless of the ionic composition of water. Modifications to the extraction process resulted only in marginal differences in the characteristics of the discharge streams. The final volume of fine tailings depends on the ultrafine content in the oil sand ore, and not on the type and concentration of the electrolyte in th process water. Although modified extraction processes resulted in faster settling, the modification produced "dirtier" (containing more clay) secondary froths, thus bringing about other process problems.},
	keywords = {oil refining},
	url = {http://search.proquest.com/docview/304214318},
	author = {Muszalski, Piotr}
}
