Distribution, occurrence mode, and extraction potential of critical elements in coal ashes of the Chongqing Power Plant. (15th March 2022)

• Record Type: Journal Article
• Authors: Xu, Fei; Qin, Shenjun; Li, Shenyong; Wang, Jinxi; Qi, De'e; Lu, Qingfeng; Xing, Jingkai
• Is Part Of: Journal of cleaner production. Volume 342(2022)
• Publication Date: 2022-03-15
• Subjects: Coal ashes -- Critical elements -- Distribution -- Occurrence mode -- Extraction potential; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2022.130910
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Critical metals play an irreplaceable role in supporting the development of the global economy and emerging industries. Their short supply makes the recovery of critical metals from alternative sources, such as coal ash, a research hotspot. In this study, Chongqing Power Plant coal and its combustion products, which are rich in a variety of critical metal elements, were selected for the study. The enrichment, distribution, and occurrence mode of critical elements in the products of coal combustion was studied, and improved sequential chemical extraction procedure, and their extraction potential was proposed and discussed. The results show that the contents of the most critical elements in different coal ashes are generally high in the order of fly ash, slag, and bottom ash. The critical elements Li, Ga, Sr, Zr, Hf, Nb, Ta, and rare earth elements and yttrium (REY) are enriched in fly ash and the contents of Ga, Nb, and REY exceed their respective industrial utilization grades, which have great recovery potential. Lithium, Ga, Nb, Ta, and REY are mainly distributed in small particle sizes in non-magnetic fly ash and occur in aluminosilicate glass, followed by mullite and quartz. Three categories of extractability are proposed: easy-to-extract form, relatively easy-to-extract, and difficult-to-extract forms. Finally, future research should focus on the collaborative extraction of multiple critical elements (such as Li, Ga, Nb, and REY) from coal ash. Graphical abstract: Image 1 Highlights: Most critical elements in different coal ashes are high. Critical elements Li, Ga, Sr, Zr, Hf, Nb, Ta, and REY are enriched in fly ash. An improved sequential chemical extraction procedure was developed. Li, Ga, Nb, Ta, and REY concentrate in small particle-sized, non-magnetic fly ash. Three categories of extractability of critical elements are proposed.