摘要
以烧结法和拜耳法生产工艺中产生的赤泥为研究材料,对其重金属和放射性元素含量进行分析,并对两种赤泥中重金属和放射性元素浸出效果进行对比研究.结果表明:两种赤泥显现出不同的理化性质.赤泥中不同重金属的含量差别较大,其中烧结法和拜耳法赤泥中As、Pb、Cr的总含量分别为256.73、120.14、828.02 mg/kg和182.82、165.83、1 043.96 mg/kg,超过我国GB 15618—1995《土壤环境质量标准》.两种赤泥中Zn、As、Pb、Mn、Ni和Th等主要以残渣态的形式存在,可交换态较少,其TCLP浸出量与其存在于交换态金属含量相近.在PBET试验中,胃部消化阶段进行到1 h时,重金属(Cu、Zn除外)及放射性元素的浸出量达到最大,小肠阶段的浸出量明显降低,在胃部消化阶段1 h时拜耳法和烧结法赤泥Pb的浸出率分别达到95.28%和97.80%,表明赤泥中的重金属及放射性元素对人体存在着较大的潜在风险.
The total contents of heavy metals and radioactive elements were analyzed for red mud generated by the sintering nd bayer processes. The leaching efficiency of the elements was comparatively studied for two kinds of red mud, B-RM and S-RM. The results showed that B-RM and S-RM samples showed different physicochemical properties, and the distinct enrichment level of heavy metals was observed for B-RM and S-RM samples. The total contents of As, Pb and Cr were 256.73,0.14 and 828.02 mg/kg for S-RM, and 182.82, 165.83 and 1043.96 mg/kg for B-RM, which far outstripped soil background values in China. Zn, As, Pb, Mn, Ni and Th mainly existed in the residual form, but less exchangeable fraction for both red mud samples. The leaching amounts obtained from TCLP were parallel to that of exchangeable fraction presented in B-RM and S-RM samples. For the PBET experiments, the extraction concentrations of heavy metals (except for Cu and Zn) and radioactive elements all reached the maximum values in gastric phase after 1 h, and the extraction percentages of Pb were 95.28% and 97.80%, respectively. However, the extraction contents of the elements obviously decreased during the small intestinal phase. This indicated that heavy metals and radioactive elements in red mud had potential bioavailability to the human body.
出处
《环境科学研究》
EI
CAS
CSCD
北大核心
2017年第5期809-816,共8页
Research of Environmental Sciences
基金
国家自然科学基金项目(5201219120004)
河南省教育厅科学技术研究重点项目(13A610514)
河南省科技攻关计划项目(142102210457)
关键词
赤泥
重金属
放射性元素
毒性浸出
生物可给性
red mud
heavy metal
radioactive elements
leaching toxicity
bioaccessibility