Selective agglomeration of fine coal using a water-in-oil emulsion

Netten, Kim van; Moreno-Atanasio, Roberto; Galvin, K.P.

doi:10.1016/j.cherd.2016.02.029

Cited by 39 publications

(28 citation statements)

References 14 publications

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“…In saying that, however, this potential reduction is highly dependent upon the emulsion acting to agglomerate the fine coal in the same manner as pure oil. This is not an unreasonable proposition and early indications have shown that a HIP emulsion can agglomerate fine coal in a similar manner to pure oil [18]. However, some significant differences between the two binders were noted as a result of this work.…”

Section: Introductionmentioning

confidence: 82%

A Kinetic Study of a Modified Fine Coal Agglomeration Process

Netten

Moreno-Atanasio

Galvin

2015

Procedia Engineering

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The process of fine coal agglomeration is a beneficiation technique that uses an organic liquid, such as, diesel, to agglomerate fine coal from an aqueous suspension of coal and mineral particles. The organic binding liquid is dispersed in the aqueous suspension through the application of agitation and selectively wets and agglomerates the hydrophobic coal particles. The hydrophilic mineral particles remain finely dispersed and, thus, the product coal agglomerates can be easily retrieved by passing the suspension over a screen. Fine coal agglomeration can achieve high quality beneficiation and allows for more effective dewatering of a fine coal feed. Regardless of these excellent capabilities, however, there are no industrial applications of this process. This is because the high cost of the oil makes the process economically unfeasible. Therefore, in this study a modified fine coal agglomeration process has been investigated in which the aim is to reduce the amount of organic liquid required in the process. The modification involves the use of a water-in-oil (W/O) emulsion as the immiscible binding liquid, replacing the conventional pure oil approach. A high internal phase (HIP) emulsion is used as it provides the interfacial functionality of the oil, while the space filling functionality is provided by the stabilised internal water droplets. In this study, an investigation into the kinetics of agglomeration of the modified process was undertaken. It was found that complete agglomeration of the carbonaceous material in the feed could be achieved by the emulsion binder in one third of the time required for a pure diesel binder. In addition, the improved kinetics were achieved by the emulsion binder at an organic liquid dosage of five-times less than required by a pure diesel binder.

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Section: Introductionmentioning

confidence: 82%

A Kinetic Study of a Modified Fine Coal Agglomeration Process

Netten

Moreno-Atanasio

Galvin

2015

Procedia Engineering

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“…Approach (ii)-increasing the apparent size of particles-includes shear flocculation [12], carrier flotation [13,14], polymer flocculation [15][16][17] and oil agglomeration [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

“…All of these techniques have their own benefits and drawbacks, but from the perspective of economics, oil agglomeration-a method to increase particle size using oil as a bridging liquid under intense mixing-is the most promising because oil is relatively inexpensive, the process could be easily integrated into existing flotation circuits, and the technique could effectively improve the recovery of fine particles. Utilization of emulsified oil for agglomeration-flotation could reduce the amount of oil [20][21][22]. This method has been mainly studied in coal flotation [19] and some sulfide minerals such as molybdenite [23], sphalerite and galena [24].…”

Section: Introductionmentioning

confidence: 99%

Agglomeration-Flotation of Finely Ground Chalcopyrite and Quartz: Effects of Agitation Strength during Agglomeration Using Emulsified Oil on Chalcopyrite

et al. 2020

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In flotation, the size of mineral particles is one of the most important parameters: when the size becomes fine, collision efficiency of the particles and air bubbles becomes low, causing low flotation recovery. To improve the collision efficiency and flotation kinetics, agglomeration using the emulsified oil of finely ground chalcopyrite (D50 = 3.5 μm) was carried out before flotation. In this study, the effects of agitation strength during agglomeration, kerosene dosage and potassium amyl xanthate (KAX) dosage on the flotation were investigated. Agglomeration using emulsified oil improved Cu recovery because the median diameter of agglomerate increased. With increasing agitation strength, KAX and kerosene dosages, Cu recovery was further increased. Agglomeration-flotation of a mixture containing chalcopyrite and quartz with 1:1 ratio (w/w, weight by weight) showed that Si recovery in froth was low and did not change with varying conditions (agitation strength, KAX and kerosene dosages); however, Cu recovery was significantly improved with increasing agitation strength, KAX and kerosene dosages, and thus the separation efficiency was improved.

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“…In other recent work, van Netten and co-workers have developed a novel hydrophobic binder for use in selective agglomeration. Originally developed with the aim of reducing the oil required in the selective agglomeration process, the hydrophobic binder has been shown to achieve rapid recovery across the full fine particle size range (van Netten et al, 2013 , 2014 , 2015 , 2016 ). A high internal-phase (HIP) water in oil emulsion is used as the binder.…”

Section: Introductionmentioning

confidence: 99%

“…Early work using the HIP water in oil emulsion binder showed a 2–3-fold (van Netten et al, 2013 ), followed by a 7-fold (van Netten et al, 2014 ) reduction in organic liquid requirements compared to conventional oil agglomeration in the recovery of coal particles. The most recent development however, resulted in a 10-fold reduction (van Netten et al, 2016 ). The hydrophobic emulsion binder consisted of a 95% dispersed aqueous phase and a 5% continuous organic phase.…”

Section: Introductionmentioning

confidence: 99%

Ultrafine Particle Recovery Using Thin Permeable Films

2018

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The selective recovery of ultrafine, <10 μm, particles remains a significant challenge in the minerals industry. Indeed, these particles often report to tailings impoundments, resulting in under-utilization of mined resources and the need for tailings dams. Recently, a technique has been developed offering the potential to selectively recover particles down to <1 μm in size. This technique, originally inspired by oil agglomeration, uses a high internal-phase water in oil emulsion as a binder to selectively agglomerate hydrophobic particles. Due to the significant concentration of the dispersed aqueous phase, ~95%, the continuous organic phase forms a network of very thin, permeable films, estimated to be 60 nm thick. These are stabilized by an emulsifier. In the high shear field of the agglomeration process, the binder is fragmented into smaller hydrophobic portions, delivering its thin film coating to the adhering hydrophobic particles. Permeation of water across the thin films eliminates the viscous hydrodynamic resistance, permitting sub-micron particle recovery to occur at rates similar to those for particles considerably larger in size. This recovery occurs within seconds under intense mixing. In this study, a model system consisting of magnetite, with a Sauter mean diameter of 11.4 μm, was agglomerated using the water in oil emulsion binder. The binder, which contained the emulsifier sorbitan monooleate, appeared to also act as a collector for the magnetite, thus no separate particle conditioning step was required. Curiously, however, the binder requirements were higher than expected. Further investigations concerning the stability of the binder revealed that the magnetite particles were causing rapid binder degradation. Therefore, prior to agglomeration using the binder, the particles were conditioned with sorbitan monooleate to render them hydrophobic. This pre-conditioning led to significant reductions in the binder dosage required to achieve agglomeration. Moreover, the resulting dosage matched that predicted by a model silica system for the same specific hydrophobic surface area, thus allowing a model to be validated based on the required binder dosage for a known hydrophobic surface area. Examination of binder stability in the presence of conditioned magnetite revealed that the now hydrophobic particles stabilized the binder.

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Selective agglomeration of fine coal using a water-in-oil emulsion

Cited by 39 publications

References 14 publications

A Kinetic Study of a Modified Fine Coal Agglomeration Process

A Kinetic Study of a Modified Fine Coal Agglomeration Process

Agglomeration-Flotation of Finely Ground Chalcopyrite and Quartz: Effects of Agitation Strength during Agglomeration Using Emulsified Oil on Chalcopyrite

Ultrafine Particle Recovery Using Thin Permeable Films

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