Effect of microwave pretreatment on oxidized coal flotation

Xia, Wencheng; Yang, Junxiao; Liang, Chuan

doi:10.1016/j.powtec.2012.09.010

Cited by 111 publications

(33 citation statements)

References 18 publications

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“…Such storage under ambient conditions leads to oxidization or weathering of some of the UC surface in the fly ash (Huang et al, 2003a;Dey et al, 2013). The weathering process might decrease the content of hydrophobic groups such as C-H and C-C groups on the coal surface and increase the content of oxygenated functional groups (i.e., hydroxyl, carbonyl, and carboxyl groups) (Xia et al, 2013a(Xia et al, , b, 2014Qu et al, 2015). McCarthy et al (2013) reported the negative effect of the weathering process on carbon recovery from CFA during flotation.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Surfactants on the Removal of Carbonaceous Matter and Dioxins from Weathered Incineration Fly Ash

Liu

Wei

et al. 2017

Aerosol Air Qual. Res.

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Our previous study demonstrated flotation to be effective in removing carbonaceous matter and dioxins from fresh fly ash in medical waste incinerators (MWIs). However, flotation of weathered fly ash seems to be difficult because of the oxidation of the ash surface and the presence of hydrophilic unburned carbon. Three types of surfactants namely nonionic Tween 80, anionic sodium dodecyl sulfate (SDS) and cationic CTAB were employed at different doses to improve flotation performance. Results indicated that Tween 80 exhibited superior decarburization performance compared with SDS and CTAB. The effect of surfactants on dioxin removal was found to correspond to the carbon removal from MWI fly ash. The optimal removal yields (90.6% of carbonaceous matter and 88.6% of dioxins) were obtained when 5% (w/w) Tween 80 was added. However, an excessive dose might cause the dissolution of dioxins.

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Section: Introductionmentioning

confidence: 99%

“…The typical methods for treating oxidized coals include thermal treatment, microwave disposal, premixing or preconditioning, and grinding (Xia et al, 2013a;Dey et al, 2013). These methods facilitate absorption of carbon by collectors or reduction of the oxygen-containing functional groups on the coal surface.…”

Section: Introductionmentioning

confidence: 99%

Effects of Surfactants on the Removal of Carbonaceous Matter and Dioxins from Weathered Incineration Fly Ash

Liu

Wei

et al. 2017

Aerosol Air Qual. Res.

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“…In another study, it was shown that the floatability of oxidized coals was improved by microwave irradiation. The results of this research revealed the increment of combustible recovery with microwave treatment time by decreasing the moisture content of oxidized coal [23]. Drying characteristics of low rank coals in a local microwave oven were investigated [24], like some variables such as particle size, microwave power level and coal sample size were mentioned.…”

Section: Introductionmentioning

confidence: 92%

Evaluation of microwave treatment on coal structure and sulfur species by reductive pyrolysis-mass spectrometry method

Mesroghli

Yperman

Jorjani

et al. 2015

Fuel Processing Technology

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“…It has been used widely in many fields including mineral leaching (AlHarahsheh and Kingman 2004;Chen et al 2011), wastewater treatment (Lin et al 2009;Remya and Lin 2011), environmental engineering and oil sand and petroleum upgrading (Jones et al 2002;Mutyala et al 2010). With the increasing emphasis on environmental issues, the application of microwave technology in the field of clean coal technology has attracted attention of experts (Zavitsanos and Blriler 1978;Meikap et al 2005;Kalra 2006; Lester et al 2006;Sahoo et al 2011;Royaei et al 2012;Ge et al 2013;Xia et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Progress of the technique of coal microwave desulfurization

Tao

Xie

et al. 2014

Int J Coal Sci Technol

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With the advantages of its fast speed, effective and moderate controllable conditions, desulfurization of coal by microwave has become research focus in the field of clean coal technology. Coal is a homogeneous mixture which consists of various components with different dielectric properties, so their abilities to absorb microwaves are different, and the sulfur-containing components are better absorbers of microwave, which makes them can be selectively heated and reacted under microwave irradiation. There still remain controversies on the principle of microwave desulfurization at present, thermal effects or non-thermal effects. The point of thermal effects of microwave is mainly base on its characters of rapidly and selectly heating. While, in view of non-thermal effect, direct interactions between the microwave electromagnetic field and sulfur containing components are proposed. It is a fundamental problem to determine the dielectric properties of coal and the sulfur-containing components to reveal the interaction of microwave and sulfur-containing compounds. However, the test of dielectric property of coal is affected by many factors, which makes it difficult to measure dielectric properties accurately. In order to achieve better desulfurization effect, the researchers employ methods of adding chemical additives such as acid, alkali, oxidant, reductant, or changing the reaction atmosphere, or combining with other methods such as magnetic separation, ultrasonic and microorganism. Researchers in this field have also put forward several processes, and have obtained a number of patents. Obscurity of microwave desulfurization mechanism, uncertainties in qualitative and quantitative analysis of sulfur-containing functional groups in coal, and the lack of special microwave equipment have limited further development of microwave desulfurization technology.

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Effect of microwave pretreatment on oxidized coal flotation

Cited by 111 publications

References 18 publications

Effects of Surfactants on the Removal of Carbonaceous Matter and Dioxins from Weathered Incineration Fly Ash

Effects of Surfactants on the Removal of Carbonaceous Matter and Dioxins from Weathered Incineration Fly Ash

Evaluation of microwave treatment on coal structure and sulfur species by reductive pyrolysis-mass spectrometry method

Progress of the technique of coal microwave desulfurization

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