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| Simulation Experiment on Control of Coal Gangue Pollution Using Sewage-sludge and Fly Ash Covering |
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| KeyWord:coal gangue; acid mine drainage; sewage sludge; fly ash; heavy metal contamination |
| Author Name | Affiliation | | MA Bao-guo | College of Hydroelectricity, Hebei University of Engineering, Handan 056021,China
Institute of Land Reclamation and Ecological Restoration, China University of Mining and Technology, Beijing 100083, China | | HU Zhen-qi | Institute of Land Reclamation and Ecological Restoration, China University of Mining and Technology, Beijing 100083, China |
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| Abstract: |
| Column leaching tests were conducted to explore the effects of sewage-sludge and fly ash covering on controlling acid and heavy metal contamination from coal gangues. Covering with sewage-sludge and fly ash significantly increased pH values but decreased Eh, EC, Fe and SO2-4 concentrations in the drainage, thus reducing concentrations of heavy metals profoundly. Concentrations of cadmium, copper, iron，lead, nickel and zinc were all lower than 0.002 mg·L-1. Additions of sewage-sludge and fly ash prevented the oxidation of sulfide in coal gangues, increased the alkalinity and adsorption, decreased the population of Thiobacillus ferrooxidans, thus enhancing immobilization of heavy metals via precipitation of sulfide and carbonate through biological（SRB） sulfate reduction, and reducing the oxidation process of sulfide through iron coating on the surface of sulfide. The results indicate that sewage-sludge and fly ash could effectively prevent acid-mine drainage and heavy metal contamination from coal gangues in situ treatment systems, and that covering with 5 cm thick sludge shows the greatest controlling effects. |
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