Enhancing treatment and geotechnical stability of oil sands fine tailings using thermo‐sensitive poly(<i>n</i>‐isopropyl acrylamide)

Li, Haihong; Zhou, Joe Zhongxiang; Chow, Ross; Adegoroye, Adebukola; Najafi, Aref Seyyed

doi:10.1002/cjce.22276

Cited by 29 publications

(14 citation statements)

References 17 publications

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“…Researchers have synthesized inorganic/organic hybrid polymeric flocculants such as Al(OH) 3 -polyacrylamide (Al-PAM) to accelerate the settling rate and enhance dewatering. The cationic nature of imbedded aluminum hydroxide can improve the performance of polyacrylamide (PAM). − Recently, temperature-responsive poly( N -isopropylacrylamide) (PolyNIPAm) has been reported as novel flocculant to accelerate settling rate and enhance consolidation. − PolyNIPAm can adsorb onto the particle surface at temperatures below the lower critical solution temperature (LCST) via hydrogen bonding interactions. By increasing the temperature above the LCST, the polymers experience a phase transition and become hydrophobic, resulting in the collapse of polymer chains. − As a result, particles in tailings suspension are rapidly flocculated and settled due to those strong hydrophobic interactions.…”

Section: Introductionmentioning

confidence: 99%

Flocculation and Dewatering of Mature Fine Tailings Using Temperature-Responsive Cationic Polymers

Zhang¹,

Thundat²,

Narain³

2017

Langmuir

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Temperature-responsive copolymer with cationic charge was prepared with N-isopropylacrylamide (NIPAm) and 2-aminoethyl methacrylamide hydrochloride (AEMA) by conventional free-radical polymerization. The flocculation performance of the copolymer, poly(AEMA-st-NIPAm), was compared to five different mixture ratios of polyNIPAm and cationic poly(acrylamide-st-diallyldimethylammonium chloride) (poly(AAm-st-DADMAC)). The effects of polymer mixture ratios, polymer dosages, and temperature on solid-liquid separation as a function of initial settling rates (ISR), supernatant turbidity, sediment solid content, and water recovery were investigated. Poly(NIPAm) can facilitate particles aggregation by bridging and hydrogen bonding under lower critical solution temperature (LCST); whereas, at temperature above LCST, the adsorption of poly(NIPAm) chains on particles can be enhanced by hydrophobic interaction. A two-step (25 °C → 50 °C → 25 °C) consolidation can further enhance the sediment solid content by polyNIPAm. While the neutral property of polyNIPAm resulted in high turbidity of supernatant, mixing with poly(AAm-st-DADMAC) increases the clarity of supernatant by neutralization of fine particles. The copolymer poly(AEMA-st-NIPAm) functions as a polyelectrolyte to enhance the polymer adsorption onto particles via electrostatic interactions, thus further improving ISR and supernatant clarity.

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Section: Introductionmentioning

confidence: 99%

Flocculation and Dewatering of Mature Fine Tailings Using Temperature-Responsive Cationic Polymers

Zhang¹,

Thundat²,

Narain³

2017

Langmuir

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“…Recent studies on PAM modification involve the addition of hydrophobic groups to increase dewatering rates. − Partially hydrophobic flocculants, including UV-initiated, , thermosensitive, , CO 2 responsive, and pH-responsive polymers, have been studied. Although most of them flocculated and dewatered tailings well, they are hard to scale up .…”

Section: Introductionmentioning

confidence: 99%

“…In the case of pH-responsive polymers, adding an alkali/acid is the limitation . Temperature-sensitive polymers, such as poly( n -isopropyl acrylamide) (PNIPAM), only become hydrophobic at higher temperatures, which raises operational costs . CO 2 -responsive flocculants, such as 2-(diethyl)aminoethyl methacrylate (DEAEMA), require large amounts of CO 2 to trigger the desired cationic behavior; maintenance costs and challenges associated with CO 2 purging make them inadequate for industrial use .…”

Section: Introductionmentioning

confidence: 99%

“…28 Temperature-sensitive polymers, such as poly(nisopropyl acrylamide) (PNIPAM), only become hydrophobic at higher temperatures, which raises operational costs. 19 challenges associated with CO 2 purging make them inadequate for industrial use. 29 Hydrophobically modified flocculants, such as amylopectin-grafted-polyacrylamide (AP-g-PAM) 20 and acrylamide/polypropylene oxide copolymers (PAM-g-PPO), 21 generated sediments with similar solids content, lower turbidity, and maximum dewatering than a reference commercial PAM but required much higher dosages (10,000 ppm).…”

Section: Introductionmentioning

confidence: 99%

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Flocculation Efficiency and Spatial Distribution of Water in Oil Sands Tailings Flocculated with a Partially Hydrophobic Graft Copolymer

Kalyanaraman

Najafabadi

Soares

et al. 2021

ACS Appl. Mater. Interfaces

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This work investigates the effect of partially hydrophobic grafted polymers on flocculation and dewatering of oil sands mature fine tailings. Here, we combine confocal microscopy and rheology to investigate how the graft density of ethylene-propylene-diene grafted with hydrolyzed poly(methyl acrylate) (EPDM-g-HPMA) affects its dispersion in water and flocculation efficiency in terms of sediment solids content and long-term dewatering of oil sands tailings. Increasing the graft density from 30 to 50% makes the flocculant easier to disperse, increases the rate of initial dewatering, and also enhances the viscoelastic response of the flocculated sediments. Conversely, the long-term rheological properties of the flocculated sediments were similar for all flocculants. Tri-dimensional microscopic details of the spatial distribution of water within the flocculated sludge provide novel insights into the performance of the flocculants. Increasing the graft density in EPDM-g-HPMA traps more water within the individual flocs and, consequently, decreases the post-flocculation dewatering rate. Our systematic approach confirms the importance of the spatial distribution of water in the flocculated sediment, which depends on how the flocculant is dispersed and how it retains water in the flocs.

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“…Of particular interest are polymer flocculants that have been used in the oil sands industry to treat FFT and mature fine tailings (MFT), a topic covered in recent reviews (Vedoy and Soares 2015;Vajihinejad et al 2019). Most flocculants used to treat FFTs are derived from PAMs, which can by synthesized as neutral, anionic, or cationic polymers (Long et al 2006;Li et al 2015;Lu et al 2015Lu et al , 2016aVedoy and Soares 2015;Reis et al 2016;Botha et al 2017;Zhu et al 2017). This flexibility has allowed PAMs to be used in a variety of systems that may require different charge characteristics.…”

Section: Introductionmentioning

confidence: 99%

Challenges in developing polymer flocculants to improve bitumen quality in non-aqueous extraction processes: an experimental study

Dixon

Stoyanov

et al. 2020

Pet. Sci.

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Western Canada's oil sands hold the third-largest hydrocarbon deposits in the world. Bitumen, a very heavy petroleum, is currently recovered by surface mining with warm water or in situ. Recovery processes that use organic solvents are being developed to reduce water usage and tailings production. While solvent-based methods can effectively extract bitumen, removal of residual fine solids from diluted bitumen product (DBP) to meet the pipeline transport requirement of < 0.5 wt% solids and water in DBP remains a major challenge. We propose a novel area of application of polymer flocculants for fine solids removal from DBP. In principle, polymer flocculants can be applied to help remove these residual solids in conjunction with physical separation processes to increase process effectiveness and energy efficiency. Several polymers are selected and screened for flocculation behavior using kaolinite suspended in DBP and toluene, as a model system. Focused beam reflectance measurements and force tensiometer techniques are used to determine flocculation and sedimentation in DBP. The observed flocculation and sedimentation rate enhancements indicate that the polymers tested have only minor effects, providing opportunities for advanced polymer development. These findings exemplify the challenges in identifying polymers that may be effective as flocculants in heavy petroleum media.Keywords Non-aqueous extraction · Diluted bitumen · Oil-soluble polymer flocculants · Sedimentation in dark and opaque media · Focused beam reflectance measurements

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Enhancing treatment and geotechnical stability of oil sands fine tailings using thermo‐sensitive poly(n‐isopropyl acrylamide)

Cited by 29 publications

References 17 publications

Flocculation and Dewatering of Mature Fine Tailings Using Temperature-Responsive Cationic Polymers

Flocculation and Dewatering of Mature Fine Tailings Using Temperature-Responsive Cationic Polymers

Flocculation Efficiency and Spatial Distribution of Water in Oil Sands Tailings Flocculated with a Partially Hydrophobic Graft Copolymer

Challenges in developing polymer flocculants to improve bitumen quality in non-aqueous extraction processes: an experimental study

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