Oil sands fluid fine tailings deposits are challenging to reclaim due to their inherently high natural water content, low permeability, and low strength. Combinations of polymers and/or coagulants are used by operators to improve the dewatering and strength properties of the tailings. However, considerably more work has been done to evaluate polymer performance with short-term dewatering metrics rather than with long-term metrics such as consolidation properties. This paper evaluates the potential of four novel polymers for use in fluid fine tailings treatment compared to a commercially available polymer and untreated tailings specimen. The performance of the polymers was assessed through initial screening with respect to short-term dewatering, evaluation of the consolidation and strength properties using large strain consolidation tests, shear sensitivity in pipeline transport, and finally, large strain consolidation modelling to appraise the relative potential performance under different strategies, such as terrestrial or aquatic reclamation options. One polymer exhibits remarkably fast dewatering at high void ratios, while another demonstrates dense and shear-resistant flocs. The paper discusses each polymer's distinctive tailings fabrics and how their unique merits and limitations would benefit different reclamation eventualities. Finally, potential improvements of the polymers are suggested for future assessment.
The result mentioned in the title of this paper was first proved by RADO [1]; a proof can also be found in [2]. The idea for the present proof is that of the first-named author, who discovered it while investigating the possibilities of engulfing in low dimensions. It is shorter than previous proofs, and is presented in the interests of economy.We commence by listing a few familiar facts from geometric topology:The Jordan-Schoenflies Theorem. A simple closed curve J in E ~ separates E 2 into two regions. There exists a self-homeomorphism of E 2 under which J is mapped onto a circle. Thickening an Arc. Each arc in the interior of a 2-manifoM lies in the interior of a 2-cell. This 2-cell can be chosen to be disjoint from anypreassigned compact set in the complement of the are. Cellularity and Quotients. For our purposes, a cellular set K is one that can be written as the intersection of a sequence of 2-cells oo K= 0 E~, where E~cIntE~_ 1 (i=2,3 .... ). i=l If K is a cellular subset of a 2-manifoM M, then M/K is homeomorphic to M. (The corresponding statement also holds in n dimensions; see [3], for example.) We shall also have need for the following Lemma. Let M be a closed 2-manifold, and let C be a connected subset of M which is the union of n simple closed curves, C= U c i. i=1 Let A be a compact, totally-disconnected subset of C. Then .4 lies in the interior of a closed 2-cell in M. (A totally-disconnected set is characterized by the property that each of its connected subsets consists of at most one point.)Proof. Since A is compact and totally-disconnected, some subarc S of C1 contains no points of A. Thicken C1-S to obtain a closed 2-cell D1 whose interior contains A n C 1.
Mature fine tailings (MFT) are one of the major environmental problems associated with the oil sands industry in Canada. To help mitigate the negative impact tailings have on the environment, we prepared MFT/starch composites and studied their morphology, water resistance, and mechanical properties as a function of filler percentage. The motivation behind this approach is to turn waste tailings into a source of potentially useful materials. We compared the MFT/starch composites to similar composites made with montmorillonite (MMT), cellulose nanocrystals (CNC), and Dean Stark solids (DS). The water resistance of MFT/starch and DS/starch composites improved 6 % at the highest filler content. MFT/starch and DS/starch composites had similar mechanical properties, but performed better than plasticized starch, with an increasing tensile modulus with increasing filler content. Despite the higher modulus increase in intercalated MMT/starch and CNC/starch composites (up to 5 % filler), the MFT/starch composites with filler contents higher than 10 % achieved the same tensile modulus values; since our objective was to transform as much MFT as possible into useable materials, this can be seen as a positive feature of these composites. The dynamic mechanical analysis of the composites showed they were heterogeneous and identified a plasticizer‐rich phase and a starch‐rich phase.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.