Fly Ash Modified Coalmine Solid Wastes for Stabilization of Trace Metals in Mining Damaged Land Reclamation: A Case Study in Xuzhou Coalmine Area

Jiu Huang, Peng Wang, Chaorong Xu and Zhuangzhuang Zhu
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Jiu Huang: School of Environment Science and Spatial Informatics, China University of Mining and Technology, 221116 Xuzhou, China
Peng Wang: State Key Laboratory for Geomechnics and Deep Underground Engineering, 221116 Xuzhou, China
Chaorong Xu: School of Environment Science and Spatial Informatics, China University of Mining and Technology, 221116 Xuzhou, China
Zhuangzhuang Zhu: School of Environment Science and Spatial Informatics, China University of Mining and Technology, 221116 Xuzhou, China

IJERPH, 2018, vol. 15, issue 10, 1-23

Abstract: In China, coalmine wastes, such as gangues, are used for reclamation of mining subsided land. However, as waste rocks, gangues contain several trace metal elements, which could be released under natural weathering and hydrodynamic leaching effects and then migrate into the reclamed soil layer. However, it is very difficult to find adequate other backfill materials for substitution of gangues. In this paper, we present a novel method and case study to restrict the migration ability of trace metal elements in gangues by using another kind of coalmine solid waste—fly ashes from coal combustion. In this study, fly ashes were mixed with gangues in different mass proportions 1:0.2, 1:0.4, 1:0.6 and 1:0.8 as new designed backfill materials. Due to the help of fly ash, the occurrence states of studied trace metal elements were greatly changed, and their releasing and migration ability under hydrodynamic leaching effect were also significantly restricted. In this research seven trace metal elements in gangues Cu, Zn, Pb, Cd, Cr, Mn and Ni were studied by using soil column hydrodynamical leaching method and simulated precipitation for one year. The results show that under the driving of natural precipitation trace metal elements were generally transported deep inside the reconstructed land base, i.e., far away from soil layer and most of the trace metal elements were transformed into a bonded state, or combined in inert occurrence states, especially the residual state. With this method, the migration activities of tested trace metal elements were greatly restricted and the environmental potential risk could be significantly reduced.

Keywords: mining gangues; subsidence backfill; occurrence states transformation; element migration (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2018
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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