title: The secondary release of mercury in coal fly ash-based flue-gas mercury removal technology.
abstract: The secondary release of mercury from coal fly ash is a negative by-product from coal-fired power plants, and requires effective control to reduce environmental pollution. Analysing particle size distribution and composition of the coal fly ash produced by different mercury removing technologies indicates that the particles are generally less than 0.5 mm in size and are composed mainly of SiO2, Al2O3, and Fe2O3. The relationships between mercury concentration in the coal fly ash, its particle size, and loss of ignition were studied using different mercury removing approaches. The research indicates that the coal fly ash's mercury levels are significantly higher after injecting activated carbon or brominating activated carbon when compared to regular cooperating-pollution control technology. This is particularly true for particle size ranges of >0.125, 0.075-0.125, and 0.05-0.075 mm. Leaching experiments revealed the secondary release of mercury in discarded coal fly ash. The concentration of mercury in the coal fly ash increases as the quantity of injecting activated carbon or brominating activated carbon increases. The leached concentrations of mercury increase as the particle size of the coal fly ash increases. Therefore, the secondary release of mercury can be controlled by adding suitable activated carbon or brominating activated carbon when disposing of coal fly ash. Adding CaBr2 before coal combustion in the boiler also helps control the secondary release of mercury, by increasing the Hg(2+) concentration in the leachate. This work provides a theoretical foundation for controlling and removing mercury in coal fly ash disposal.
authors.affiliation: a School of Chemical Engineering and Technology , China University of Mining and Technology , Xuzhou 221116 , People's Republic of China.|b Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education , China University of Mining and Technology , Xuzhou 221116 , People's Republic of China.
authors.forename: Jingfeng
authors.initials: J
authors.lastname: He
authors.affiliation: a School of Chemical Engineering and Technology , China University of Mining and Technology , Xuzhou 221116 , People's Republic of China.|b Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education , China University of Mining and Technology , Xuzhou 221116 , People's Republic of China.
authors.forename: Chenlong
authors.initials: C
authors.lastname: Duan
authors.affiliation: a School of Chemical Engineering and Technology , China University of Mining and Technology , Xuzhou 221116 , People's Republic of China.
authors.forename: Mingzhe
authors.initials: M
authors.lastname: Lei
authors.affiliation: c Institute of solid waste management , Chinese Research Academy of Environmental Sciences , Beijing 100012 , People's Republic of China.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Zhu
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000517:prevention & control*; D060729:Coal Ash / Q000032:analysis*; D004784:Environmental Monitoring; D017745:Incineration; D008628:Mercury / Q000032:analysis*; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis; D018505:Waste Management / Q000379:methods*
chemical_list: D000393:Air Pollutants; D060729:Coal Ash; D052638:Particulate Matter; D008628:Mercury
keywords: activated carbon; coal fly ash; flue-gas; mercury; secondary release