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Название: Kinetics Study of Al Extraction from Desilicated Coal Fly Ash by NaOH at Atmospheric Pressure
Авторы: Shoppert, A.
Loginova, I.
Valeev, D.
Дата публикации: 2021
Издатель: MDPI
MDPI AG
Библиографическое описание: Shoppert A. Kinetics Study of Al Extraction from Desilicated Coal Fly Ash by NaOH at Atmospheric Pressure / A. Shoppert, I. Loginova, D. Valeev // Materials. — 2021. — Vol. 14. — Iss. 24. — 7700.
Аннотация: The most promising source of alumina in the 21st century is the coal fly ash (CFA) waste of coal-fired thermal plants. The methods of alumina extraction from CFA are often based on the pressure alkaline or acid leaching or preliminary roasting with different additives followed by water leaching. The efficiency of the alumina extraction from CFA under atmospheric pressure leaching is low due to the high content of acid-insoluble alumina phase mullite (3Al2O3·2SiO2). This research for the first time shows the possibility of mullite leaching under atmospheric pressure after preliminary desilication using high liquid to solid ratios (L:S ratio) and Na2O concentration. The analysis of the desilicated CFA (DCFA) chemical and phase composition before and after leaching has been carried out by inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray diffraction (XRD). The morphology and elemental composition of solid product particles has been carried out by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). An auto-mated neural network and a shrinking core model (SCM) were used to evaluate experimental data. The Al extraction efficiency from DCFA has been more than 84% at T = 120◦C, leaching time 60 min, the L/S ratio > 20, and concentration of Na2O-400 g L−1. The kinetics analysis by SCM has shown that the surface chemical reaction controls the leaching process rate at T < 110◦C, and, at T > 110◦C after 15 min of leaching, the process is limited by diffusion through the product layer, which can be represented by titanium compounds. According to the SEM-EDX analysis of the solid residue, the magnetite spheres and mullite acicular particles were the main phases that remained after NaOH leaching. The spheric agglomerates of mullite particles with non-porous surface have also been found. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Ключевые слова: ALKALINE
COAL FLY ASH
KINETICS
LEACHING
MACHINE LEARNING
MULLITE
NEURAL NETWORK
SHRINKING CORE MODEL
ADDITIVES
ALKALINITY
ALUMINA
ALUMINUM OXIDE
CHEMICAL ANALYSIS
COAL
COAL ASH
ENERGY DISPERSIVE SPECTROSCOPY
EXTRACTION
INDUCTIVELY COUPLED PLASMA
KINETICS
LEACHING
MACHINE LEARNING
MORPHOLOGY
SCANNING ELECTRON MICROSCOPY
SILICA
SODIUM HYDROXIDE
SURFACE REACTIONS
ACID LEACHING
ALKALINE LEACHING
ALKALINES
ALUMINA EXTRACTIONS
COAL FLY ASH
ENERGY DISPERSIVE X RAY SPECTROSCOPY
KINETIC STUDY
NEURAL-NETWORKS
SHRINKING CORE MODEL
THERMAL PLANTS
FLY ASH
URI: http://elar.urfu.ru/handle/10995/112121
Условия доступа: info:eu-repo/semantics/openAccess
Идентификатор РИНЦ: 47543638
Идентификатор SCOPUS: 85121292535
Идентификатор WOS: 000738728200001
Идентификатор PURE: 29147550
ISSN: 1996-1944
DOI: 10.3390/ma14247700
Сведения о поддержке: Funding: This work was funded by State Assignment, grant № 075-03-2021-051/5. The method of Al content analysis in CFA by ICP-OES was funded by a Ministry of Science and Higher Education of the Russian Federation scientific topic № 0137-2019-0023.
Располагается в коллекциях:Научные публикации ученых УрФУ, проиндексированные в SCOPUS и WoS CC

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