A novel process to extract alumina and prepare Fe-Si alloys from coal fly ash

Yang, Xue; Yu, Wenzhou; Jiang, Weiyan; Wen, Lin; You, Zhixiong; Lv, Xuewei

doi:10.1016/j.fuproc.2018.12.013

Cited by 25 publications

(17 citation statements)

References 21 publications

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“…Therefore, smart and more practically valuable approaches for the utilization of FA have been under development in recent years. For example, fly ash particles have been investigated as fillers in polymers [6], in the processing of architectural ceramics [7], and as a source of other valuable materials [8,9]. The conversion of FA into zeolites has potentially the greatest environmental benefits due to the broad application of these materials in water-, air-and soil-cleaning technologies.…”

Section: Introductionmentioning

confidence: 99%

Progress in the Utilization of Coal Fly Ash by Conversion to Zeolites with Green Energy Applications

et al. 2020

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Fly ash (FA) from lignite coal combusted in different Thermal Power Plants (TPPs) was used for the synthesis of zeolites (FAZs) of the Na-X type by alkaline activation via three laboratory procedures. FAZs were characterized with respect to their morphology, phase composition and surface properties, which predetermine their suitability for applications as catalysts and adsorbents. FAZs were subsequently modified with metal oxides (CuO) to improve their catalytic properties. The catalytic activity of non-modified and CuO-modified FAZs in the total oxidation of volatile organic compounds was investigated. FAZs were studied for their potential to retain CO2, as their favorable surface characteristics and the presence of iron oxides make them suitable for carbon capture technologies. Thin films of FAZs were deposited by in situ crystallization, and investigated for their morphology and optical sensitivity when exposed to pollutants in the gas phase, e.g., acetone. This study contributes to the development of novel technological solutions for the smart and valuable utilization of FA in the context of the circular economy and green energy production.

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Section: Introductionmentioning

confidence: 99%

Progress in the Utilization of Coal Fly Ash by Conversion to Zeolites with Green Energy Applications

et al. 2020

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“…Metallic Fe, obtained from the reaction of Fe 2 O 3 and carbon, could combine with Si to form Fe−Si alloys as byproducts and lower the activity of Si. 122,123 Carbochlorination follows the same principle but uses Cl as an auxiliary component. Cl can be added during the process of carbothermal reduction, followed by separation to obtain silicon tetrachloride (SiCl 4 ), aluminum chloride (AlCl 3 ), and titanium tetrachloride (TiCl 4 ).…”

Section: ■ Elemental Extraction Techniquesmentioning

confidence: 99%

“…Combinations of techniques can achieve a higher efficiency of elemental extraction than their individual applications. For example, acidic dissolution and ion exchange, 121 microwave irradiation and acid dissolution, 90 carbothermal reduction and magnetic separation, 122 alkali and acid dissolution, 69,125 alkali fusion and acid dissolution, 36,105,119 and multistep sequential extraction have all been attempted. 81,126 Sequential extractions of Si and Al have been extensively studied, based on which mesoporous silica or alumina has been synthesized for wider use.…”

Section: ■ Elemental Extraction Techniquesmentioning

confidence: 99%

High-End Reclamation of Coal Fly Ash Focusing on Elemental Extraction and Synthesis of Porous Materials

Han

Meng

et al. 2021

ACS Sustainable Chem. Eng.

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Coal combustion accounts for a large proportion of the global energy supply due to its low cost and high heat value; however, pollution from the large amounts of coal fly ash (CFA) generated during the process causes many environmental problems. CFA has traditionally been used in construction and soil remediation, although there have been attempts to use CFA in response to the developing shortage of mineral resources. Numerous studies have investigated high-end recycling of CFA to obtain valuable products such as critical metals and porous materials, which are widely used in chemical engineering, ecological remediation, and other fields. In this study, we found that various extraction and synthesis methods summarized high value-added treatments of CFA. Dissolution and sintering processes were applied for extraction, while carbothermal and electrolysis techniques offered other unique advantages. The precursors and polymers used in the procedures were the two main factors influencing the synthesis of porous materials, providing a source of elements and inducing the formation of predictable structures. Considering the mechanisms involved, the complex methods used in state-of-the-art CFA recycling could be combed to develop high value-added CFA reclamation techniques.

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“…In addition, acids are normally volatilizable and expensive, resulting in relatively uneconomic extraction process. Moreover, acid leaching method may cause corrosion on the metal pipes and equipment, which limits its practical applications [24,25].…”

Section: Introductionmentioning

confidence: 99%

Extraction of alumina from alumina rich coal gangue by a hydro-chemical process

et al. 2020

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Vast quantities of gangue from coal mining and processing have accumulated over the years and caused significant economic and environmental problems in China. For high added-value utilization of alumina rich coal gangue (ARCG), a mild hydro-chemical process was investigated to extract alumina. The influences of NaOH concentration, mass ratio of alkali to gangue, reaction temperature and reaction time were systematically studied. An alumina extraction rate of 94.68% was achieved at the condition of NaOH concentration 47.5%, alkali to gangue ratio of 6, reaction temperature of 260°C and reaction time of 120 min. The obtained leaching residues were characterized through X-ray diffraction, scanning electron microscopy and energy-dispersive spectrometer. Research confirmed that kaolinite the main alumina-bearing phase of ARCG can be decomposed and transformed to Na 8 Al 6 Si 6 O 24 (OH) 2 (H 2 O) 2 and Ca 2 Al 2 SiO 6 (OH) 2 at relatively low temperature and short reaction time. Additionally, Na 8 Al 6 Si 6 O 24 (OH) 2 (H 2 O) 2 and Ca 2 Al 2 SiO 6 (OH) 2 are unstable and will transform to alumina-free phase NaCaHSiO 4 under the optimal conditions, which is the major reason for high alumina extraction rates.

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A novel process to extract alumina and prepare Fe-Si alloys from coal fly ash

Cited by 25 publications

References 21 publications

Progress in the Utilization of Coal Fly Ash by Conversion to Zeolites with Green Energy Applications

Progress in the Utilization of Coal Fly Ash by Conversion to Zeolites with Green Energy Applications

High-End Reclamation of Coal Fly Ash Focusing on Elemental Extraction and Synthesis of Porous Materials

Extraction of alumina from alumina rich coal gangue by a hydro-chemical process

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