Image Processing For Quantitative Analysis of Fluid Fine Tailing’s, Dosed With Anionic Polyamide Based Flocculant

Muhammad Hissan khattak, Paul Simms, Muhammad Asif

Dans les comptes rendus d’articles de la conférence: GeoEdmonton 2018: 71st Canadian Geotechnical Conference; 13th joint with IAH-CNC

Session: Geoenvironmental Engineering I

ABSTRACT: Understanding long-term dewatering behaviour of oil sands tailings is significant to the success and optimization of tailings reclamation plans. Long term dewatering, of tailings is somewhat complex due to mechanical creep and or structuration driven by electrochemical forces, between clay particles. To modernize conceptual models of tailings dewatering, fabric evolution, of tailings over months has been studied using, Porosmetry, SEM, ESEM, as well as optical microscopy. Morphological, information is extracted from various images using a variety of image processing techniques. In this context, -Image fabric investigation and quantitative analysis, of the amended fluid fine tailings (FFT). The long-term fabric evolution in an initially 0.10 m thick sample suggests growth in aggregate size, increase in average pore-size, although decrease in porosity.

RÉSUMÉ: Comprendre le comportement d'assèchement à long terme des résidus de sables bitumineux est important pour le succès et l'optimisation des plans de remise en état des résidus miniers. La déshydratation à long terme des résidus est quelque peu complexe en raison du fluage mécanique et / ou de la structuration entraînée par les forces électrochimiques, entre les particules d'argile. Afin de moderniser les modèles conceptuels de l'assèchement des résidus, l'évolution des tissus, des résidus au fil des mois a été étudiée à l'aide de la porosmétrie, du MEB, de l'ESEM et de la microscopie optique. Morphologique, l'information est extraite des diverses images en utilisant une variété de techniques de traitement d'image. Dans ce contexte, l'idée principale de cette étude était d'utiliser le logiciel "Image processing", principalement "Fiji-Image J" pour l'étude des tissus et l'analyse quantitative de la FFT modifiée. L'évolution à long terme du tissu dans un m échantillon épais suggère une croissance de la taille des agrégats, augmentation de la taille moyenne des pores, bien que la diminution de la porosité. INTRODUCTION Dewatering of oil sands tailings to facilitate reclamation and ecological restoration of tailings disposal areas remains quite challenging. Tailings disposal technologies and practices certainly are open to further optimization to increase effectiveness of dewatering and to reduce costs (COSIA 2015). Oil sands tailings are initially composed of water, residual bitumen, sands, and fines (silts and clays). The coarser particles i.e. >44um, settle and segregate from the remaining tailings quickly after deposition. The fine particles remain suspended and termed FFT (fluid fine tailings). After few years of placement in the tailings ponds, FFT only settles to about 30% or 35%, and thereafter do not appreciably dewater (Beier et al. 2009, Chalaturnyk et al. 2002). Consequently, oil sands operators have developed several technologies to accelerate dewatering, such as centrifugation and in-line flocculation. Polymer induced flocculation of fines is incorporated in many of the new tailings technologies. Such technologies can increase the solid content to 50- 55% by mass, in hours to days. (Matthews et al., 2011, Wells, 2011). However, dry land reclamation may require upwards of 70% solids content. Therefore, understanding the long-term dewatering, behavior of oil sands tailings is important to the success and optimization of tailings reclamation plans. The processes involved in the dewatering, of oil sands tailings over a longer time (months to years), not only incudes consolidation, but may be influenced by creep or thixotropy /structuration. Recent laboratory work (Salam et al. 2017) suggests that such time-dependent behavior may bear substantially on the dewatering behavior of polymer amended FFT deposits. The work in this paper complements the investigations of Salam et al (2017) and others, by attempting to visualize physical changes in the fabric of tailings as they progress through different stags of dewatering, from scales of hours to months. To this end, Images are obtained using SEM/ ESEM and a high-power optical microscope. The images are analyzed using freeware Image J and digital image processing techniques, to quantify fabric evolution in polymer amended tailings. The long-term goal of the work is to improve conceptual models of tailings dewatering that could allow for further optimization of polymer does, type, and application. MATERIALS PREPEARTION AND SAMPLING This FFT had a sand to fine ratio of 0.25, an MBI estimate clay content of 28 % to 32%. An anionic polyamide-based flocculant was prepared in a 0.4 % stock solution and applied to the tailings at a dosage of 600 ppm. The tailings

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