Physicochemical properties and heavy metals leachability of fly ash from coal-fired power plant

Xiang Wei (1, 2) , Han Baoping (3) , Zhou Dong (4) , Ange Nzihou (2)

1 School of Environment Science and Spatial Informatics, China University of Mining & Technology
2 RAPSODEE - Centre de recherche d'Albi en génie des procédés des solides divisés, de l'énergie et de l'environnement
3 Xuzhou Institute of Technology
4 Beijing Puresino-Boda Environmental Engineering Co., Ltd.

The physicochemical properties of fly ash from two kinds of coal-fired power plants were studied. Three aspects were examined: the micro-morphology, the mineral composition and the content of heavy metals. The results show that the fly ash from plants using a circulating fluidized bed are more irregular particles , while the particles from the plants using a pulverized coal-fired boiler are mainly spherical in shape. Quartz and mullite are the main crystalline phases in the ash. Clearly, both the technology and the coal used by a power plant can influence the mineral composition of the ash. The mineral composition of fly ash from a circulating fluidized bed is more complex than that from a pulverized coal-fired boiler. The quantity of elements found in the fly ash is greater than that found in the bottom ash for the same plant. Heavy metals are likely to be enriched in the fly ash. Heavy metal leachability was studied using two leaching methods. The results indicate that most of the heavy metals that leached during either batch leaching or column leaching experiments did not exceed the related maximum concentration standards. But Ni concentrations in the leachates from both batch and column tests exceed the standard. The highest excess rates in both tests were 572% and 497%, which levels might threaten the environment.

Domains: Engineering Sciences [physics]; Materials; Engineering Sciences [physics]; Mechanics [physics.med-ph]; Thermics [physics.class-ph]; Engineering Sciences [physics]; Chemical and Process Engineering; Environmental Sciences; Environmental Engineering

Xiang Wei, Han Baoping, Zhou Dong, Ange Nzihou. Physicochemical properties and heavy metals leachability of fly ash from coal-fired power plant. International Journal of Mining Science and Technology, 2012, 22 (3), pp.405 - 409. ⟨10.1016/j.ijmst.2011.12.002⟩. ⟨hal-01798131⟩