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为了考察赣南某钨矿尾矿砂及其周围土壤中砷的赋存状态及释放特征,通过二乙基二硫代氨基甲酸银分光光度法对尾矿砂和矿区周围土壤中的砷进行了全量分析,同时采用Tessier连续提取法和静态释放试验对不同形态的砷进行提取与分析。结果表明:尾矿砂中砷的质量比达到63.2 mg/kg,主要以残渣态的形式存在,残渣态砷占总砷的39.4%;周边土壤中砷的平均质量比达到83.83 mg/kg,已受到了严重的砷污染,土壤中砷主要以铁锰氧化物结合态的形式存在,占总砷的36.13%~38.63%;而且离尾矿砂堆越近,土壤中砷的富集越明显。尾矿砂和土壤中砷的释放能力受外界条件和体系pH值等因素的影响。经振荡处理后,尾矿砂和土壤中砷的释放量有明显提高;砷在酸性条件下的释放能力小于碱性条件下的释放能力,而且在一定范围内释放量会随pH值升高而增加。
In order to investigate the occurrence and release characteristics of arsenic in the tailings sand and surrounding soil of a tungsten mine in southern Jiangxi Province, the total amount of arsenic in the tailings sand and the soil around the mining area was analyzed by silver diethyldithiocarbamate spectrophotometry At the same time, Tessier continuous extraction method and static release test were used to extract and analyze arsenic with different morphologies. The results showed that the mass ratio of arsenic in the tailing sand reached 63.2 mg / kg, which was mainly in the form of residual state, the residual arsenic accounted for 39.4% of the total arsenic, and the average mass ratio of arsenic in the surrounding soil was 83.83 mg / kg. Severe arsenic pollution, arsenic in the soil mainly in the form of iron-manganese oxide bound state, accounting for 36.13% to 38.63% of the total arsenic; and closer to the tailings sand, the more obvious the enrichment of arsenic in the soil. The release of arsenic in tailing sand and soil is affected by external conditions and pH value of the system. After shaking treatment, the release of arsenic in tailing sand and soil was significantly increased. The release of arsenic in acidic condition was lower than that in alkaline condition, and the release of arsenic increased with the increase of pH within a certain range .