Chloride removal from municipal solid waste incineration fly ash using lactic acid fermentation broth. (1st July 2021)

• Record Type: Journal Article
• Authors: Wang, Xiaona; Gao, Ming; Wang, Menglu; Wu, Chuanfu; Wang, Qunhui; Wang, Ying
• Is Part Of: Waste management. Volume 130(2021)
• Page Start: 23
• Page End: 29
• Publication Date: 2021-07-01
• Subjects: Fly ash -- Dechlorination -- Lactic acid fermentation broth leaching -- Water-insoluble chlorine; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2021.05.014
• Languages: English
• ISSNs: 0956-053X

Abstract

Graphical abstract: Highlights: Dechlorination of fly ash by lactic acid fermentation broth was investigated. WLL leaching protocol yielded the highest dechlorination efficiency. Cl removal from fly ash might be prohibited by the newly formed calcium salts. Undissolved Cl in residue might wrap inside the crystal structure of CaAlSiO4 (OH). Abstract: As far as improvement of chlorine removal from fly ash by lactic acid fermentation broth (LAFB) was concerned, it is particularly important to explore the instinct mechanism and understand how leaching protocols (i.e. lactic acid addition amount and timing) affect the dechlorination efficiency. Results revealed that the WLL leaching protocol yielded the highest dechlorination efficiency (i.e. removed 98.7% of the total chlorine content of fly ash). The undissolved chlorine in fly ash residue might wrap inside the crystal structure of CaAlSiO4 (OH). Given that the chlorine removal from fly ash might prohibit by the newly formed calcium salt precipitation, exclusively increase the addition amount of LAFB (i.e. LLL protocol) did not necessarily stimulate the dechlorination efficiency. Conversely, it might accelerate the fly ash mass reduction (compared with WLL protocol), resulting in a high chlorine content in fly ash residue. Therefore, instead of increasing lactic acid strength, reducing the thickness of the calcium salt precipitation layer or breaking the crystal structure of CaAlSiO4 (OH) during the leaching process was suggested for efficient fly ash dechlorination.