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| Effects of bauxite residue on soil salinize-alkalization under simulated rainfall conditions |
| Received:February 28, 2017 |
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| KeyWord:bauxite residue;soil column;acid rain leaching;soil salinize-alkalization;exchangeable base cations |
| Author Name | Affiliation | E-mail | | LIU Ji-dong | College of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China | | | DU Ping | State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China | | | REN Jie | State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
College of Water Science, Beijing Normal University, Beijing 100875, China | | | CHEN Juan | State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China | | | LIU Xiao-lian | College of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China | | | XU Gang | College of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China | | | WU Ming-hong | College of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China | mhwu@shu.edu.cn |
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| Abstract: |
| To understand the influence of alkaline substances from bauxite residue under simulated acid rain and rainfall, a soil column experiment with bauxite residue of different thicknesses was conducted. The soil saline-alkali indicators included soil pH, exchangeable sodium percentage(ESP), and electric conductivity(EC). The pH, organic matter, bulk density, and water content of the soil around the bauxite residues storage facility were 8.68, 25.66 g·kg-1, 1.20 g·cm-3, and 12.01%, respectively. Results indicated that the pH of soil at 0~10 cm depth increased significantly, and the maximum pH was 10.18. Compared with the original soil, the soil pH at 10~30 cm depth increased to 8.67~9.12, and there were no obvious changes at 30~60 cm depth. The ESP of surface soils(0~10 cm) were lower than 15% in the condition of 5 cm bauxite residue coverage under simulated rainfall, while ESP in other conditions were higher than 15%, which indicated that the soil alkalization occurred. The soil ESP at 10~40 cm depth increased to 5.38%~14.70%, which presented a trend of alkalization. With only a slight increase of EC, the salinization of soil was not obvious. The maximum concentrations of the leachates Na, K, Mg, and Ca were 125.86, 2.23, 57.13, and 209.07 mg·L-1, respectively, which indicate strong migration, potentially influencing the groundwater. Under trial conditions, the effects of bauxite residue on soil alkalization were more significant and increased with the thickness of the bauxite residue coverage. Moreover, the effects were more serious with the acid rain leaching than with rainfall. |
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