Reduction of undesirable element leaching from fly ash by adding hydroxylated calcined dolomite

Quanzhi Tian, Binglin Guo, Shingo Nakama, Li Zhang, Zhaochu Hu, Keiko Sasaki

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Fly ash always contains many toxic elements which can be released into environment, thereby easily leading to environmental contaminations. In order to dispose fly ash safely, related strategies are needed. In this investigation, two kinds of hydroxylated calcined dolomites (HCD60 and HCD100) were used as the additives and compared with lime on the leachabilities of anionic species from fly ash. Both additives were found effective in reducing the leaching concentrations of these elements, which was better than that of only lime addition. Mg(OH) 2 and MgO were believed to play important roles in the hydration reaction of fly ash. In the presence of Mg(OH) 2 and MgO, there were more hydration products including calcium silicate hydrate, ettringite, hydrocalumite and other Layered double hydroxides (LDHs) generated which were effective candidates for anion removal. Thus, the final leaching results were controlled by these newly formed phases through adsorption, incorporation or encapsulation. On the other hand, compared with Mg(OH) 2 , MgO can promote the formation of hydration products in a larger extent because of the hydration process of MgO into Mg(OH) 2 . There was no systematic trend in the promotion of fly ash hydration by Mg(OH) 2 or MgO because it had a close relationship with the properties of original fly ash. Objectively, hydroxylated calcined dolomites can be promising candidate additives for reduction of toxic elements leaching from fly ash.

Original languageEnglish
Pages (from-to)23-35
Number of pages13
JournalWaste Management
Volume86
DOIs
Publication statusPublished - Mar 1 2019

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fly ash
dolomite
leaching
hydration
lime
encapsulation
hydroxide
anion
silicate
calcium
adsorption
additive

All Science Journal Classification (ASJC) codes

  • Waste Management and Disposal

Cite this

Reduction of undesirable element leaching from fly ash by adding hydroxylated calcined dolomite. / Tian, Quanzhi; Guo, Binglin; Nakama, Shingo; Zhang, Li; Hu, Zhaochu; Sasaki, Keiko.

In: Waste Management, Vol. 86, 01.03.2019, p. 23-35.

Research output: Contribution to journalArticle

Tian, Quanzhi ; Guo, Binglin ; Nakama, Shingo ; Zhang, Li ; Hu, Zhaochu ; Sasaki, Keiko. / Reduction of undesirable element leaching from fly ash by adding hydroxylated calcined dolomite. In: Waste Management. 2019 ; Vol. 86. pp. 23-35.
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