Effect of the intensification of preconditioning on the separation of unburned carbon from coal fly ash

Lu, Yang; Li, Danlong; Zhu, Zhenna; Xu, Ming; Yan, Xiang-Ping; Zhang, Haijun

doi:10.1016/j.fuel.2019.01.038

Cited by 55 publications

(11 citation statements)

References 49 publications

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“…However, because of the incomplete combustion of coal, FA contains more than 6% unburned carbon,. which cannot be utilized in the synthesis of zeolites. − If the FA is activated by the other appropriate methods, excellent zeolite or activated adsorbents can be obtained. Bandura et al prepared the zeolite–carbon composites of faujasite and gismondite using high-carbon fly ash (HCFA) as the raw material via a single-step hydrothermal conversion with NaOH, and the results indicated that their adsorption capacity for oil was up to 1.39 g/g.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Honeycomb-Structured Activated Carbon–Zeolite Composites from Modified Fly Ash and the Adsorptive Removal of Pb(II)

Zhao

Chen

et al. 2022

ACS Omega

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In this paper, fly ash (FA) was successfully prepared into a honeycomb carbon–zeolite composite (CZC) with good adsorption and used for the removal of Pb(II) by a two-step method. Compared with general FA, the honeycomb structure of the CZC resulted in a ∼6× increase in the specific surface area, and the average pore size increased from 3.4 to 12.7 μm. The maximum adsorption capacity of CZCs for Pb(II) reached 185.68 mg/g in 40 min. The experimental data for the adsorption of Pb(II) by CZC showed that the results were in good agreement with the Langmuir adsorption model. The adsorbent prepared in this study has good application prospects in wastewater treatment and provides a new method for the resource recovery of FA.

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Section: Introductionmentioning

confidence: 99%

Preparation of Honeycomb-Structured Activated Carbon–Zeolite Composites from Modified Fly Ash and the Adsorptive Removal of Pb(II)

Zhao

Chen

et al. 2022

ACS Omega

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“…The mode of the microbubble diameter was about 40 μm. In addition, in device II, a 60 wt% fly ash slurry and the collector were pre-stirred in a 0.6 L high-speed mixer before flotation due to the significant improvement in the separation performance of unburned carbon from coal fly ash [ 31 ]. Pretreatment has great importance for the flotation method.…”

Section: Methodsmentioning

confidence: 99%

Development of Flotation Device for Removing Unburnt Carbon in Fly Ash for Use in Hardened Cementitious Materials

et al. 2021

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The unburned carbon in fly ash inhibits the performance of concrete. A device using the flotation method to remove unburned carbon in fly ash was developed, and the operating condition of the device was experimentally examined. According to the results, the device was able to remove unburnt carbon from fly ash by using the installed micro bubble nozzles and a whirl-type pump. The removal efficiency of unburnt carbon improved when prior forced stirring was carried out by a concrete mixer for 3 min, and a scavenger was added into the fly ash slurry at a density of about 60 wt%. It has also been confirmed that the method of circulating water is more effective than the method of not circulating water. The elements of the modified fly ash slurry (MFAS) have also been experimentally confirmed as not being too different from untreated fly ash, except for the fact that the content of unburned carbon is reduced. The compressive strength and drying shrinkage characteristics of concrete made with MFAS were investigated. The use of MFAS will reduce the performance of concrete compared to that of ordinary concrete. This shows that in a certain range (15–30%), the influence of MFAS on drying shrinkage is constant. The static elastic modulus and dynamic elastic modulus were also investigated. The above results show that the application of MFAS prepared by the flotation method to concrete is feasible.

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“…Thus, the non-magnetic fraction particles 71-100 µm in size were used for flotation tests. Diesel was chosen as the collector of flotation due to its high effectivity and low price [29]. MIBC was used in flotation tests to prevent coalescence of air bubbles, to increase the force of adhesion of bubbles to floating carbon particles and to promote the formation of a stable foam on the surface of the pulp.…”

Section: Carbon Flotation Of the Non-magnetic Fraction Of Cfamentioning

confidence: 99%

Magnetite and Carbon Extraction from Coal Fly Ash Using Magnetic Separation and Flotation Methods

et al. 2019

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In this study, enrichment methods for coal fly ash (CFA) from Omsk thermal power station No. 4 (TPS-4) were investigated. The magnetite and unburned carbon concentrates were obtained by magnetic separation and flotation methods. The wet magnetic separation used in the study increased the magnetite content in the magnetic fraction from 10.48 to 12.72 wt % compared to dry magnetic separation. The XRD analysis showed that the magnetic fraction primarily consists of magnetite, mullite, and quartz. The SEM analysis demonstrated that magnetite is located primarily on the surface of alumosilicate spheres and has three types of shape: dendritic structures, hexagonal bulk agglomerates, and star-like structures. For the flotation tests, a low-price diesel was used as the collector. It was found that, if CFA particles of 40–71 µm are used, ~99% of unburned carbon can be recovered. It was also found by SEM that, if CFA particles of 71–100 µm are used, alumosilicates on a carbon surface prevent complete interaction of diesel with carbon particles and decrease thereby carbon recovery to 83%.

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Effect of the intensification of preconditioning on the separation of unburned carbon from coal fly ash

Cited by 55 publications

References 49 publications

Preparation of Honeycomb-Structured Activated Carbon–Zeolite Composites from Modified Fly Ash and the Adsorptive Removal of Pb(II)

Preparation of Honeycomb-Structured Activated Carbon–Zeolite Composites from Modified Fly Ash and the Adsorptive Removal of Pb(II)

Development of Flotation Device for Removing Unburnt Carbon in Fly Ash for Use in Hardened Cementitious Materials

Magnetite and Carbon Extraction from Coal Fly Ash Using Magnetic Separation and Flotation Methods

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