The effect of emulsification on the selective agglomeration of fine coal

Bensley, C.N; Swanson, Andrew R.; Nicol, S.K.

doi:10.1016/0301-7516(77)90024-2

Cited by 59 publications

(22 citation statements)

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“…This process is generally referred to as selective agglomeration. Various researchers (Cheh et al, 1982;Bensley et al, 1977;Schubert, 1974) have worked on reducing the oil consumption by using emulssed oil. The main reason that a large amount of oil is used for selective agglomeration is to have the convenience of separating the agglomerates from the dispersed mineral matter by simple screening.…”

Section: Selective Agglomerationmentioning

confidence: 99%

“…However, selective oil agglomeration suffers from one major disadvantage, that is, the large amount of oil consumption. Isrpically, 10% or more of oil by weight of feed solids is required for cleaning coal containing large portions of minus 325 mesh (45 pm) material.Various researchers (Cheh et al, 1982;Bensley et al, 1977;Schubert, 1974) have worked on reducing the oil consumption by using emulssed oil. The main reason that a large amount of oil is used for selective agglomeration is to have the convenience of separating the agglomerates from the dispersed mineral matter by simple screening.…”

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confidence: 99%

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Novel microorganism for selective separation of coal from pyrite and ash. Final report

Misra¹,

Smith²

1995

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In keeping with the main objective of the project, the separation of fine coal from ash and pyrite was conducted using a microorganism Mycobacterium phlei (M. phlei). The surface hydrophobicity and surface charge ofMycobacterium phlei and it's sonicated products (extracellular soluble fractions) were established using contact angle and electrophoretic measurements.Mycobacterium phlei was highly hydrophobic and point-of-zero charge was around pH 2. The hydrophobic character and negative surface charge of the microorganism above pH 2 were due to the presence of excessive fatty groups at the surface and corresponding carboxylate groups. In addition, soluble fractions derived from the cell exhibited the presence of varying amounts of fatty acids ranging from C,, -C,, carbon chain and phosphate groups.The surface chemistry analyses of coal, coal-pyrite, mineral pyrite and quartz were conducted. The adhesion of Mycobacterium phlei onto coal, coaliii .. ..e..,,-pyrite and quartz was measured as a function of pH and Mycobacterium phlei concentration. It was noticed that Mycobacterium phlei selectively attached to hydrophobic coal particles and did not attach to hydrophilic mineral fractions.Adhesion was strongly dependent on pH and maximum adhesion was observed in an acidic pH range of 3-4.On the basis of the detailed surface chemistry analysis, adhesion and contact angle measurements, a series of flocculation and flotation experiments were conducted. The experimental results showed that Mycobacterium phlei was an excellent flotation collector and flocculating agent. However, the soluble fkaction derived from Mycobacterium phlei by sonication was a better flotation collector and flocculating agent for fine coal than whole cells of Mycobacterium phlei. In order to selectively separate the coal-Myco bacterium phlei entities, a modified floc-flotation technique was used. At an optimized experimental condition, more than 70 percent pyritic sulfur and 60 percent of ash could be rejected with a combustible (clean coal) recovery of 90 percent. During this investigation, it was established that Mycobacterium phlei and more importantly it's sonication products had a strong potential to be used for selective flocculation and separation of fine coal from associated mineral matters.. . . The impurities occurring in coal may be classified broadly into those that form ash and those that contribute sulfur. From the standpoint of coal cleaning, both the ash-forming and the sulfur-containing impurities may be subdivided into two categories -inherent and extraneous. The inherent impurities are inseparably combined with the coal. The extraneous impurities are segregated and can be eliminated by the available cleaning methods.Sulfur occurs in coal in three different forms. It is present in organic compounds as part of the coal substance, as sulfides, generally pyrite or marcasite, and as sulfate. The amount of organic sulfur normally is not over 3%.The sulfates, mainly calcium and iron, rarely exceed a few hundredths...

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Section: Selective Agglomerationmentioning

confidence: 99%

mentioning

confidence: 99%

Novel microorganism for selective separation of coal from pyrite and ash. Final report

Misra¹,

Smith²

1995

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“…The collectors need to spread over the coal surface for effective flotation. Previous work has demonstrated the correlation between flotation efficiency and the dispersibility of the oily collector in the pulp, i.e., an increase in collector dispersibility results in an increase in flotation recovery (Bensley et al, 1977;Cebeci, 2002). However, collectors are typically added directly to the pulp and dispersed by the shearing forces in the flotation cell, resulting in poor collector dispersion.…”

Section: Introductionmentioning

confidence: 99%

Effects of Surfactant Headgroups on Oil‐in‐Water Emulsion Droplet Formation: An Experimental and Simulation Study

Zhang

Liu

et al. 2018

J Surfact & Detergents

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Nonpolar oils such as kerosene and diesel oil are common collectors in coal flotation. Surfactants are usually added to the pulp to emulsify the oil collectors. The present study used dodecane as the oil collector and anionic sodium dodecyl sulfonate (SDS) and nonionic tetraethylene glycol monododecyl ether (C12EO) with different headgroups and identical chain alkyls to investigate the effect of the surfactant headgroups on oil‐in‐water emulsion droplet formation. The morphology and stability of dodecane emulsions were determined experimentally. Density functional theory (DFT) and molecular dynamics (MD) simulations were used to explain the microscopic mechanism. The results of DFT indicated a larger interaction between SDS and the water molecules than that between C12EO and water molecules. The results obtained by MD suggested that the SDS headgroup exhibited a loose arrangement and a relatively large gap size, thereby weakening the interaction between SDS and water molecules at the dodecane/water interface. In contrast, the headgroups of C12EO were bent and interwoven with others to form a tight reticulation at the interface. According to the simulation results, the ability of the surfactant to form dodecane‐in‐water emulsion droplets depends on the arrangement of the surfactants at the oil–water interface rather than on the interaction strength between the headgroups of the surfactants and water molecules. The presented microscopic mechanism of the surfactant headgroup formation of oil‐in‐water emulsion droplets offers surfactant selection and design references.

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“…Hence, flotation, selective flocculation and selective agglomeration are widely used in fine coal processing. A satisfactory number of studies on fine coal flotation have been reported [1][2][3][4]. However, relatively few studies have been dedicated to the action and mechanism of flotation reagents in coal flotation [5,6].…”

Section: Introductionmentioning

confidence: 99%

Mechanism of fine coal flotation using insoluble collectors in the presence of frothers.

Salmawy

Seifelnassr

Abdelaal

et al. 1997

Resources Processing

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The effect of emulsification on the selective agglomeration of fine coal

Cited by 59 publications

References 0 publications

Novel microorganism for selective separation of coal from pyrite and ash. Final report

Novel microorganism for selective separation of coal from pyrite and ash. Final report

Effects of Surfactant Headgroups on Oil‐in‐Water Emulsion Droplet Formation: An Experimental and Simulation Study

Mechanism of fine coal flotation using insoluble collectors in the presence of frothers.

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