title: Distribution and mode of occurrence of uranium in bottom ash derived from high-germanium coals.
abstract: The radioactivity of uranium in radioactive coal bottom ash (CBA) may be a potential danger to the ambient environment and human health. Concerning the limited research on the distribution and mode of occurrence of uranium in CBA, we herein report our investigations into this topic using a number of techniques including a five-step Tessier sequential extraction, hydrogen fluoride (HF) leaching, Siroquant (Rietveld) quantification, magnetic separation, and electron probe microanalysis (EPMA). The Tessier sequential extraction showed that the uranium in the residual and Fe-Mn oxide fractions was dominant (59.1% and 34.9%, respectively). The former was mainly incorporated into aluminosilicates, retained with glass and cristobalite, whereas the latter was especially enriched in the magnetic fraction, of which about 50% was present with magnetite (Fe3O4) and the rest in other iron oxides. In addition, the uranium in the magnetic fraction was 2.6 times that in the non-magnetic fraction. The experimental findings in this work may be important for establishing an effective strategy to reduce radioactivity from CBA for the protection of our local environment.
authors.affiliation: Department of Environmental Engineering, School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: sunyinglong.007@163.com.
authors.forename: Yinglong
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Environmental Engineering, School of Environment, Tsinghua University, Beijing 100084, China; Department of Environmental Science and Engineering, School of Food and Chemical Engineering, Beijing Technology and Business University, Beijing 100048, China.
authors.forename: Guangxia
authors.initials: G
authors.lastname: Qi
authors.affiliation: Department of Environmental Engineering, School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Xuefei
authors.initials: X
authors.lastname: Lei
authors.affiliation: Department of Environmental Engineering, School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Xu
authors.affiliation: Department of Environmental Engineering, School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Environmental Engineering, School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Yuan
authors.affiliation: Department of Environmental Engineering, School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: yi_wang@tsinghua.edu.cn.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
mesh_terms: D060729:Coal Ash / Q000737:chemistry*; D004577:Electron Probe Microanalysis; D005857:Germanium; D011210:Power Plants; D011834:Radiation Monitoring; D011848:Radioactive Pollutants / Q000032:analysis*; D014501:Uranium / Q000032:analysis*
chemical_list: D060729:Coal Ash; D011848:Radioactive Pollutants; D005857:Germanium; D014501:Uranium
keywords: Coal bottom ash; Magnetic separation; Radioactivity; Tessier sequential extraction; Uranium