黏性土对铀尾矿酸性渗滤水的净化性能研究

STUDY ON PURIFICATION ABILITY OF CLAY SOIL ON ACIDIC SEEPAGE FROM URANIUM TAILINGS

采用动态柱实验研究黏性土对酸性铀尾矿渗滤液的净化作用,结果表明:该黏性土对有害物质有一定的阻滞能力,渗滤液中的污染物在土柱中迁移速度为:SO2-4>U(Ⅵ)>As>226Ra>Th(Ⅳ)。土柱对渗滤液物质的去除率大小依次为:Th(Ⅳ)>226Ra>As>U(Ⅵ)>SO42-,其值分别是35.3%、32.1%、17.7%、11.2%、4.5%,土壤对酸有一定的缓冲能力,使得渗滤液pH值由2.90上升到3.69,该黏性土对U(Ⅵ)、Th(Ⅳ)、226Ra与As的分配系数分别为2.33,14.25,11.08,4.67 m/g,此结果可以为该尾矿库地下水的污染预测提供计算参数。

Column experiments were conducted to study the purification ability of clay soil against the acidic seepage from uranium tailings. The results showed the clay soil could retard migration of contaminants in seepage, and the descending sequence of the migration speed in the soil column was SO4^2-〉U（Ⅵ） 〉As〉^226Ra〉Th（Ⅳ）, the descending order of soil removal rate of contaminants in the seepage was Th（Ⅳ） 〉 226 Ra 〉 As 〉 U （Ⅵ） 〉 SO24 , 35.3% ,32. 1%, 17.7%, 11.2% and 4. 5% respectively. The soil had buffer capacity to acidic, making the pH value of seepage increasing from 2. 90 to 3.79. The sorption distribution coefficients of the total thorium（IV）, 226Raium, total arsenic and total uranium（Ⅵ）in the clay soil were 14. 25, 11.08, 4. 67, 2. 33 mL/g respectively, which could provide calculation parameters for predicting the groundwater pollution in the similar sites.