Quantifying the effect of polyacrylamide dosage, Na+ and Ca2+ concentrations, and clay particle size on the flocculation of mature fine tailings with robust statistical methods

Motta, Fernanda Lopes; Gaikwad, Rohankumar; Botha, Linda; Soares, João B. P.

doi:10.1016/j.chemosphere.2018.05.171

Cited by 27 publications

(14 citation statements)

References 27 publications

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“…In the early stage of settling, the slurry undergoes strong agitation, and the particles are affected by turbulence, resulting in coagulation. When the turbulence effect weakens gradually [13], the particles settle naturally under gravity and the velocity increases gradually until the resistance and gravity are balanced to reach the ultimate velocity. When the particles continue to settle, the interference settlement will occur when they contact the decelerated settled particles at the bottom.…”

Section: Mechanism Of Flocculation Actionmentioning

confidence: 99%

Optimization of Flocculation Settling Parameters of Whole Tailings Based on Spatial Difference Algorithm

2019

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In order to obtain the optimum parameters of total tailings flocculation settling, an optimization method of total tailings flocculation settling parameters based on the spatial difference algorithm was proposed. Firstly, the input and output factors of the whole tailings flocculation settling parameters are effectively analyzed, and the relevant factors affecting the flocculation settling parameters are obtained. Secondly, the flocculation settling velocity of the whole tailings is optimized by combining the spatial difference algorithm with the mathematical symmetry algorithm, and the optimal value of the flocculation settling velocity of the whole tailings is obtained. The experimental results show that anionic flocculation has the best flocculation settling effect on the whole tailings. The optimal settlement velocity is close to the actual settlement velocity, and the error of settlement velocity is less than 3.5%. The results show that compared with the traditional method, this method is an effective method to optimize the flocculation and settlement parameters of the whole tailings.

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Section: Mechanism Of Flocculation Actionmentioning

confidence: 99%

Optimization of Flocculation Settling Parameters of Whole Tailings Based on Spatial Difference Algorithm

2019

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“…Motta et al. used surface response methodologies to investigate the impact of cation concentration (Na + and Ca 2+ ) and anionic PAM dosage, as well as their interactions, in MFT dewatering MFT . They also examined the effect of clay particle size during the flocculation of samples with distinct particle size distributions (PSDs).…”

Section: Multifunctional Linear Polymer Flocculantsmentioning

confidence: 99%

Section: Multifunctional Linear Polymer Flocculantsmentioning

confidence: 99%

“…From a fundamental perspective, the effects of cation concentration (Na + and Ca 2+ ) must be isolated from that of anionic PAM dosage to differentiate the role of each parameter on flocculation. Motta and coworkers combined particle size and zeta potential measurements to investigate the mechanism of floc formation . Figure shows a schematic representation of changes in particle surface area, zeta potential, and particle size.…”

Section: Multifunctional Linear Polymer Flocculantsmentioning

confidence: 99%

Section: Multifunctional Linear Polymer Flocculantsmentioning

confidence: 99%

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Advanced Polymer Flocculants for Solid–Liquid Separation in Oil Sands Tailings

Gumfekar

Vajihinejad

Soares

2018

Macromol. Rapid Commun.

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volume of tailings is projected to reach two billion cubic meters in 2034 if tailings management procedures remain the same. [3] When fresh tailings consolidate for a few years after their transfer to tailings ponds, gravitational forces cause the coarse components (sands) to settle, releasing a limited amount of the water to the surface. The bottom part of the remaining suspension is called mature fine tailings (MFT). Typically, MFT contains negatively charged clays (≈30-35 wt%), water (≈65 wt%), and residual bitumen (3-5 wt%). [4] Compared to fresh tailings, which still contain coarse particles that consolidate over time, MFT is a gel-like suspension that consolidates extremely slowly. Clays in MFT contain mainly kaolinite, illite, and mixedlayer clays such as interstratified illitesmectite and kaolinite-smectite. [5] Fine clays are mostly responsible for the water retained in MFT due to their high surface area. Additionally, fugitive bitumen binds clay particles, constricting interparticle pathways and trapping water. Colloidal Stability of Tailings and Challenges in DewateringSince MFT contains a mixture of negatively charged clays, it shows strong negative zeta potential that causes colloidal stabilization. Generally, clays contain hydroxyl and oxide functional groups that make their particles negatively charged at neutral pH (pH = 7) and even more negative as pH increases. Thus, the stability of clays in MFT increases with increase in pH. Current bitumen extraction processes use caustic additives to liberate bitumen from oil sands, generating alkaline tailings with pH of approximately 8.5. This alkaline medium increases the electrostatic repulsive forces between clays and significantly increases MFT stability. Surface charges also arise when ions from the neighboring solution adsorb on an initially neutral solid surface. Another source of surface charges is the dissociation of surface groups. The silica surface of clays can react with water to form silicic acid, which can then dissociate to form a silicic anion, as shown below. SiOHO HSiO (HSiO ) H 2 S 2 2 3 S 3 S ( ) ( ) + ↔ ↔ + − +(1) Multifunctional FlocculantsThe generation of tailings as a by product of the bitumen extraction process is one of the largest environmental footprints of oil sands operations. Most of the tailings treatment technologies use polymer flocculants to induce solid-liquid separation. However, due to the complex composition of tailings, conventional flocculants cannot reach the same performance achieved in other wastewater treatments. Over the last couple of decades, the oil sands industry has used acrylamide-based flocculants to treat tailings, achieving major progress in process optimization and integration with mechanical operations, but they still could not reach the required land reclamation targets. Over the last 5 years, the group designed, synthesized, and tested several novel polymer flocculants tailored for oil sands tailings treatment. This feature article communicates recent developments in these innovative polymers. Th...

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Amylopectin graft copolymers for oil sands tailings treatment

Davey

Soares

2021

Can J Chem Eng

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The oil sands industry has contributed to the Canadian economy for over 50 years. Challenges have arisen, however, due to worldwide concerns regarding the long-term environmental impact of waste by-products generated in the bitumen extraction process from oil sands. Reclaiming legacy tailings and reducing the number of ponds are two of these challenges. This article describes the synthesis and characterization of amylopectin-graft-hydrolyzed-poly(methyl acrylate) copolymers with different graft lengths and densities, and how they can be used to treat oil sands tailings. Flocculation and dewatering results depend strongly on how the hydrophobic amylopectin backbones are combined with the hydrophilic hydrolyzed poly(methyl acrylate) grafts. These hybrid polymers, combining a natural backbone with synthetic grafts, seem to be an attractive alternative to treat oil sands and probably other mineral ore tailings.

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Quantifying the effect of polyacrylamide dosage, Na+ and Ca2+ concentrations, and clay particle size on the flocculation of mature fine tailings with robust statistical methods

Cited by 27 publications

References 27 publications

Optimization of Flocculation Settling Parameters of Whole Tailings Based on Spatial Difference Algorithm

Optimization of Flocculation Settling Parameters of Whole Tailings Based on Spatial Difference Algorithm

Advanced Polymer Flocculants for Solid–Liquid Separation in Oil Sands Tailings

Amylopectin graft copolymers for oil sands tailings treatment

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