Analytical Electron Microscopy of Carbon-Rich Mineral Aggregates in Solvent-Diluted Bitumen Products from Mined Alberta Oil Sands

Couillard, Martin; Mercier, Patrick H. J.

doi:10.1021/acs.energyfuels.6b00708

Cited by 8 publications

(15 citation statements)

References 40 publications

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“…Ti, in the form of rutile or anatase, and Ca, in the form of apatite, carbonates, and sulphates, are also present. The analysis also confirms the presence of a non-negligible amount of carbon (7.67 wt %), which is expected to be found in carbonates, as well as toluene-unextractable organic carbon in micron-sized carbonaceous particles and intermixed with clay minerals [25].…”

Section: Analytical Characterization Of Sub-2 µM Total Clay Fraction Of Contaminant Solidssupporting

confidence: 65%

“…Bulk analyses of the elemental and mineralogical compositions of the four sub-2 µm clay solid fractions isolated as explained above were obtained as described in Couillard and Mercier [25] using: (i) Rietveld analysis of the mineral contents by powder X-ray diffraction (XRD), (ii) elemental analyses of metal concentrations (Si, Al, K, Mg, Fe, Ti, Zr, Mg, Ca, and P) by X-ray fluorescence (XRF) spectrometry, and (iii) measurements of total contents of carbon and sulfur. Commercial equipment and associated software were used for XRD profile collection (Bruker AXS D8 Advance system-powder diffractometer, Bruker, Billerica MA, USA), Rietveld analysis with TOPAS 5.1 (Bruker AXS, Karlsruhe, Germany), XRF elemental analysis (Bruker AXS S4 Pioneer XRF Spectrometer), and carbon and sulfur measurements (Elementar vario EL cube); see Couillard and Mercier [25] for details on sample preparation and instrumental conditions. The bulk mineralogical compositions of the sub-2 µm clay solid fractions were quantified using the singular-value decomposition quantitative phase analysis (SVD-QPA) methodology described previously [25,35,36].…”

Section: Methodsmentioning

confidence: 99%

“…Commercial equipment and associated software were used for XRD profile collection (Bruker AXS D8 Advance system-powder diffractometer, Bruker, Billerica MA, USA), Rietveld analysis with TOPAS 5.1 (Bruker AXS, Karlsruhe, Germany), XRF elemental analysis (Bruker AXS S4 Pioneer XRF Spectrometer), and carbon and sulfur measurements (Elementar vario EL cube); see Couillard and Mercier [25] for details on sample preparation and instrumental conditions. The bulk mineralogical compositions of the sub-2 µm clay solid fractions were quantified using the singular-value decomposition quantitative phase analysis (SVD-QPA) methodology described previously [25,35,36]. Table 1 lists the mineral and amorphous (i.e., poorly-crystalline or finely dispersed) phases included for quantitative determination of the mineralogical compositions of the sub-2 µm clay solid fractions using the SVD-QPA mineralogy.…”

Section: Methodsmentioning

confidence: 99%

“…Table 1. List of mineral and amorphous phases included for determination of mineralogical composition using SVD-QPA methodology [25,35,36]. The term "amorphous" refers to poorly-crystalline or finely-dispersed phases not discernable in XRD powder patterns.…”

Section: Methodsmentioning

confidence: 99%

“…In particular, an inhomogeneous organic coverage of clay platelet surfaces may result in a biwettable character for the platelets, favoring their accumulation at bitumen-water interfaces [23]. Such a patchy coating has been inferred from various surface science methods [24], and directly mapped using transmission electron microscopy [25] and atomic force microscopy [26] analysis. The organic carbon was assigned to humic and asphaltene-like substances [24,27].…”

Section: Introductionmentioning

confidence: 99%

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Structure and Mineralogy of Hydrophilic and Biwettable Sub-2 µm Clay Aggregates in Oil Sands Bitumen Froth

et al. 2020

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A primary concern of commercial mined oil sands operations is the extent to which one can minimize the content of water and solids contaminants in the solvent-diluted bitumen products resulting from the bitumen production processes. During bitumen production, particles of about 2 µm or less may be responsible for the stabilization of water-in-bitumen emulsions that form during aqueous extraction of bitumen and purification of bitumen froth subsequently during the froth treatment processes, thus leading to the presence of those contaminants in solvent-diluted bitumen products. In this study, we separate and analyze sub-2 µm clay solids isolated from typical bitumen froth fed to a froth treatment plant at a commercial mined oil sands operation. Analytical transmission electron microscopy (TEM) with spatially-resolved energy-dispersive X-ray spectroscopy (EDX) and electron energy-loss spectroscopy (EELS) demonstrate key differences in morphology and composition between sub-2 µm clay aggregates with two distinct wettability characteristics: hydrophilic vs. biwettable particle surfaces. In particular, clay platelets with <200 nm lateral dimensions and thicknesses of a few atomic layers, which are intermixed within coarser sub-2 µm clay aggregates, are found to confer clear differences in morphological characteristics and wettability behaviors to the sub-2 µm clay aggregates. The <200 nm clay platelets found within sub-2 µm biwettable clays tend to arrange themselves with random orientations, whereas <200 nm clay platelets within sub-2 µm hydrophilic clays typically form well-ordered face-to-face stacks. Moreover, in biwettable sub-2 µm clay aggregates, <200 nm clay platelets often cover the surfaces of ~1–2 µm sized mineral particles, whereas similarly sized mineral particles in hydrophilic sub-2 µm clay aggregates, in contrast, generally have exposed surfaces without clay platelet coverage. These biwettable vs. hydrophilic behaviors are attributed to a difference in the surface characteristics of the <200 nm clay platelets caused by toluene-unextractable organic carbon coatings. Nanometer-scale carbon mapping reveals an inhomogeneous toluene-unextractable organic carbon coating on the surfaces of <200 nm platelets in biwettable clays. In contrast, hydrophilic clays have a significantly lower amount of toluene-unextractable organic carbon, which tends to be concentrated at steps or near metal oxide nanoparticles on clay particle surfaces. Mixing surface-active organic species, such as asphaltene, resin, or carboxylic organic acids of various types with inorganic solids can lead to a dramatically enhanced emulsion stability. Consequently, understanding the origin and characteristics of sub-2 µm clay solids in bitumen froth is important to (i) clarify their potential role in the formation of stable water-in-oil emulsions during bitumen production and (ii) improve froth treatment process performance to further reduce contaminant solids in solvent-diluted bitumen products. We discuss the implications of our results from these two perspectives.

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Section: Analytical Characterization Of Sub-2 µM Total Clay Fraction Of Contaminant Solidssupporting

confidence: 65%