Coal Flotation with Nonionic Surfactants

Harris, Guy H.; Diao, J.; Fuerstenau, D.W.

doi:10.1080/07349349508905248

Cited by 91 publications

(24 citation statements)

References 6 publications

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“…Polar collectors, surfactants with oxygenated groups, are found more effective than fuel oils in the flotation of oxidized coals. Harries et al [13] reported that a much lower dosage of non-ionic surfactants was required to achieve the same flotation performance for low-rank coals compared with nonpolar oil collectors. Jia et al [14] proposed that the surfactants with oxygenated groups and benzene rings may interact with the oxidized coal surfaces through van der Walls forces, π bonding and hydrogen bonding.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…where y represents the dosage of X-100 (mol/t) required to achieve 80% flotation yield and x is the Some researchers proposed that the polar groups of surfactants could bond to the oxygenated groups on oxidized coal surfaces [13,14,38] with their nonpolar hydrocarbon chains orientated towards the liquid phase to enhance the surface hydrophobicity of oxidized coals. Recently, Gui et al…”

Section: Accepted Manuscriptmentioning

confidence: 99%

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Understanding and improving the flotation of coals with different degrees of surface oxidation

2017

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In this study, the research was designed to answer two questions: how does the degree of surface oxidation affect coal flotation and how to improve the flotation of coals with different degrees of surface oxidation? The degree of coal surface oxidation was quantified as the percentage of oxidized carbon by X-ray photoelectron spectroscopy (XPS), and flotation tests were conducted to determine the flotation behavior of coals with different degrees of surface oxidation. It was found that coal flotation performance decreased with an increase in the degree of surface oxidation. A critical degree of coal surface oxidation was observed in flotation and, above it, the true flotation of coals was impossible. To improve the flotation of oxidized coals, diesel (a nonpolar collector) and Triton X-100 (a polar collector) were mixed as a composite collector to enhance the hydrophobicity of both un-oxidised and oxidized coal surfaces simultaneously. Flotation tests demonstrated a significant increase in the flotation of oxidized coals after the addition of X-100. A close relationship between the degree of coal surface oxidation and the proportion of X-100 in the composite collector used to achieve the optimal coal flotation was identified: the higher the degree of coal surface oxidation, the higher the proportion of X-100 required. This study indicates that the best composite collector used to float an oxidized coal may be formulated based on the degree of surface oxidation. of a Turkish bituminous coal. Fuel processing technology, 1998. 55(2): p. 101-105. 7. Dey Shobhana, P.G.M., Pani Santosh, Flotation behaviour of weathered coal in mechanical and column flotation cell. Powder Technology, 2013. 246(0): p. 689-694.8.

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Section: Accepted Manuscriptmentioning

confidence: 99%

Section: Accepted Manuscriptmentioning

confidence: 99%

Understanding and improving the flotation of coals with different degrees of surface oxidation

2017

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“…Non-ionic surfactants and water-soluble polymers have been utilized to modify the coal surface (Harris, 1995). Li et al (1992) who used a comb-like polymer found that the coal became more hydrophobic with increasing promoter concentration regardless of its original floatability.…”

Section: Effect Of Coal Particle -Promoter Interactions On Flotationmentioning

confidence: 99%

Physical and chemical interactions in coal flotation

Polat

Chander

2003

International Journal of Mineral Processing

191

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Coal flotation is a complex process involving several phases (particles, oil droplets and air bubbles). These phases simultaneously interact with each other and with other species such as the molecules of a promoting reagent and dissolved ions in water. The physical and chemical interactions determine the outcome of the flotation process. Physical and chemical interactions between fine coal particles could lead to aggregation, especially for high rank coals. Non-selective particle aggregation could be said to be the main reason for the selectivity problems in coal flotation. It should be addressed by physical (conditioning) or chemical (promoters) pretreatment before or during flotation. Although the interactions between the oil droplets and coal particles are actually favored, stabilization of the oil droplets by small amounts of fine hydrophobic particles may lead to a decrease in selectivity and an increase in oil consumption. These problems could be remedied by use of promoters that modify the coal surface for suitable particle -particle, droplet -particle and particle -bubble contact while emulsifying the oil droplets. The role of promoters may be different for different types of coals, however. They could be employed as modifiers to increase the hydrophobicity of low rank coals whereas their main role might be emulsification and aggregation control for high rank coals. In this paper, a detailed description of the various phases in coal flotation, their physical and chemical interactions with each other in the flotation pulp, the major parameters that affect these interactions and how these interactions, in turn, influence the flotation process are discussed. D

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“…Usually, the collector dosage in high rank coals is much smaller than that in low rank coals [85]. Therefore, some effective collectors are invented as well as some surfactants are needed in the flotation of low rank coal [86][87][88][89][90].…”

Section: Flotationmentioning

confidence: 99%