The oil sands industry is currently facing a challenge by regulators to develop dewatering technologies that can halt any further growth in the massive size of existing tailings ponds and also reclaim the contents of those ponds. The most recent technology involves in-tank and/or in-line addition of flocculants followed by a dewatering step (e.g. centrifugation, thin-lift dewatering). This work has focused on three different dewatering technologies. Firstly, a high-throughput method was developed to investigate the effects of ionic composition adjustment on MFTs dewatering through a centrifugation process. As a result, it was found that samples with different concentrations and valency of cations had different settling kinetic and higher concentrations and valency of cations caused faster settling. Also, changes in the ionic composition of samples suggest that there is a strong interaction (ion exchanging) between MFTs and added solution. Secondly, the effects of different factors (e.g. freezing time and temperature) on freeze-thaw dewatering of MFTs were studied using a temperature monitoring setup. It was found that partial freezing causes less dewatering compared to complete freezing after thawing. Finally, a lab-scale unit of low-speed rotary filtration was built and it was implemented to dewater polymer amended MFTs. By using this unit, effects of different factors were investigated on the dewatering efficiency of the rotary filtration unit through a DOE study. The DOE results showed that the flocculation conditions have a big impact on performance of the rotary filtration and for some of the DOE conditions, cakes were formed with more than 47 wt% which couldn’t be reached by just gravity settling of polymer amended MFTs. Also, freeze-thaw of the cakes after rotary filtration could increase the solids content. / Thesis / Master of Applied Science (MASc) / The oil sands industry has been challenged by regulators to develop dewatering technologies that can stop any further growth in the massive size of existing tailings ponds and also reclaim the contents of those ponds. The current dewatering technologies have different challenges that were tried to address in this study. At the first part of the research, it was tried to develop a method for rapid investigation of the effects of salt addition followed by a mechanical method (centrifugation) on dewaterability of MFTs. In the second part it was tried to investigate freeze-thaw as a natural dewatering technique and also to investigate the possibility of mechanizing this process. In the last part, an alternative dewatering technology (rotary filtration), that is predicted to be cheaper than centrifugation, was used to dewater MFTs (amended by polymer). Therefore, a lab-scale version was made and used for polymer amended MFTs dewatering. By using this technology the solids content of MFT had around 20 wt% increase (compare to the untreated MFTs).
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/19129 |
| Date | January 2016 |
| Creators | Zafari, Farhad |
| Contributors | Latulippe, David, Chemical Engineering |
| Source Sets | McMaster University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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