Alternative techniques for extracting alumina from coal fly ash

Shemi, A.; Mpana, R.N.; Ndlovu, Sehliselo; Dyk, L. Van; Sibanda, Vusumuzi; Seepe, L.

doi:10.1016/j.mineng.2012.04.007

Cited by 96 publications

(28 citation statements)

References 6 publications

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“…Previously, aluminum has been recovered from CFA using hydrometallurgy techniques such as solvent extraction [13], acid leaching [14][15][16][17][18], alkaline leaching [19][20][21], and acid/alkali combination methods [22]. The CFA may be pre-processed before leaching using auxiliary reinforcement methods, such as lime stone sintering [6], soda lime sintering [23], and ammonium sulfate sintering [14,24].…”

Section: Introductionmentioning

confidence: 99%

An Efficient Approach for Lithium and Aluminum Recovery from Coal Fly Ash by Pre-Desilication and Intensified Acid Leaching Processes

Qin

Kang

et al. 2017

Metals

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A novel technique was developed for the recovery of lithium and aluminum from coal fly ash using a combination of pre-desilication and an intensified acid leaching process. The main components of the high-aluminum fly ash were found to be Al 2 O 3 and SiO 2 , and the Al/Si ratio increased from 1.0 to 1.5 after desiliconization. The lithium content of the coal fly ash met national recycling standards. The optimal acid leaching conditions, under which the leaching efficiencies of lithium and aluminum were 82.23% and 76.72%, respectively, were as follows: 6 mol/L HCl, 1:20 solid to liquid ratio, 120 • C and 4 h. During the hydrochloric acid pressure leaching process, spherical particles of desilicated fly ash were decomposed into flakes. Part of the mullite phase was dissolved, and most of the glass phase leached into the liquor. The generation of the silicates hindered lithium transport, which decreased the leaching rate of lithium. This work suggests that the preprocessing is a promising option for effective recovery of high-aluminum and fly ash-associated lithium.

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Section: Introductionmentioning

confidence: 99%

An Efficient Approach for Lithium and Aluminum Recovery from Coal Fly Ash by Pre-Desilication and Intensified Acid Leaching Processes

Qin

Kang

et al. 2017

Metals

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“…The beneficiation of South African FA after it has been put through a process of air classification, electrostatic recovery and/or density separation has been described before [1], and specific size fractions of FA, with specific physical and chemical properties, may be used in suitable applications. The country's research and development involving FA includes its application in building and construction as cement extender and into lightweight aggregates [4], environmental rehabilitation in the form of counteracting acid mine drainage, wastewater treatment, and toxic element immobilization by zeolites [5][6][7], mine backfilling, the recovery of alumina [8,9], production of geopolymers [10,11] and hydrotalcites [12], soil amelioration [13], refractories and bricks, road stabilization, CO 2 capture [14], and as a processing aid and functional filler in polymers [15].…”

Section: Introductionmentioning

confidence: 99%

Surface and bulk characterization of an ultrafine South African coal fly ash with reference to polymer applications

Merwe

Prinsloo

Mathebula

et al. 2014

Applied Surface Science

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“…Seeley et al [169] used the Calsinter process to recover alumina and the recovering rate reached more than 95%. Shemi et al [170] employed a direct acid leach process to extract aluminia.…”

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confidence: 99%

A comprehensive review on the applications of coal fly ash

Yao

Sarker

et al. 2015

Earth-Science Reviews

1,422

568

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Coal fly ash, an industrial by-product, is derived from coal combustion in thermal power plants. It is one of the most complex anthropogenic materials, and its improper disposal has become an environmental concern and resulted in a waste of recoverable resources. There is a pressing and ongoing need to develop new recycling methods for coal fly ash. The present review first describes the generation, physicochemical properties and hazards of coal fly ash at the global level, and then focuses on its current and potential applications, including use in the soil amelioration, construction industry, ceramic industry, catalysis, depth separation, zeolite synthesis, etc.Finally, the advantages and disadvantages of these applications, the mode of fly ash utilization worldwide and directions for future research are considered.

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Alternative techniques for extracting alumina from coal fly ash

Cited by 96 publications

References 6 publications

An Efficient Approach for Lithium and Aluminum Recovery from Coal Fly Ash by Pre-Desilication and Intensified Acid Leaching Processes

An Efficient Approach for Lithium and Aluminum Recovery from Coal Fly Ash by Pre-Desilication and Intensified Acid Leaching Processes

Surface and bulk characterization of an ultrafine South African coal fly ash with reference to polymer applications

A comprehensive review on the applications of coal fly ash

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