CGF固化/稳定化重金属污染土强度及浸出特性  

Strength and leaching characteristics of CGF solidification/stabilization heavy metal contaminated soil

作　　者：常睿卿 杨俊杰[1,2] 武亚磊 鲁瑞帆 CHANG Rui-qing;YANG Jun-jie;WU Ya-lei;LU Rui-fan(Key Lab of Marine Environmental and Ecology,Ministry of Education,Qingdao 266100,China;College of Environmental Science and Engineering,Ocean University of China,Qingdao 266100,China)

机构地区：[1]海洋环境与生态教育部重点实验室,山东青岛266100 [2]中国海洋大学环境科学与工程学院,山东青岛266100

出　　处：《中国环境科学》2024年第5期2580-2594,共15页China Environmental Science

基　　金：国家自然科学基金资助项目(52378380,52078474,51779235)。

摘　　要：通过CGF(由电石渣、粒化高炉矿渣、粉煤灰组成的固废基固化剂)固化/稳定化不同土质种类(由不同黏粒、粉粒、砂粒配比调配)、不同复合重金属(Cu、Ni、Pb、Zn)含量的污染土,借助宏微观试验研究固化/稳定化污染土的强度特性、重金属浸出特性以及固化/稳定化机理.研究结果表明:CGF固化/稳定化重金属污染土强度和重金属浸出浓度主要由养护龄期、重金属含量和土质种类共同决定;随着养护龄期的增加,固化/稳定化污染土强度逐渐增加,但不同重金属含量的强度变化规律不同,存在重金属“临界含量”;随着养护龄期的增加,重金属浸出浓度逐渐减小,其浸出浓度变化规律亦存在重金属“临界含量”,该“临界含量”由养护龄期和土质种类控制,固化/稳定化Clay污染土在7,28,90d的“临界含量”分别为200,300,600mg/kg,28d时固化/稳定化Clay、CSSM511、CSSM111污染土“临界含量”分别为300,200,200mg/kg,固化/稳定化CSSM011污染土不存在“临界含量”.CGF固化/稳定化重金属污染土作用机理包括固化剂对重金属离子的化学沉淀、包裹、吸附、离子交换等稳定化作用和土中黏土矿物对重金属离子的稳定化作用.Contaminated soils with different soil types(different proportions of clay,silt and sand)and different composite heavy metals(Cu,Ni,Pb and Zn)content were solidified/stabilized by CGF(a solid waste based binder composed of calcium carbide residue(CCR),ground granulated blastfurnace slag(GGBS)and fly ash(FA)),macro and micro tests were conducted to study the strength characteristics,heavy metal leaching characteristics and solidification/stabilization mechanism of the solidified/stabilized contaminated soil.The results show that the strength and leaching concentration of heavy metal contaminated soil solidified/stabilized by CGF were mainly determined by curing time,heavy metal content and soil type;With the increase of curing time,the strength of solidified/stabilized contaminated soil gradually increased,leaching concentration was negatively correlated with curing time,there is a"critical content"of heavy metal,which was controlled by the type of heavy metal ions and the type of soil.The"critical content"of solidified/stabilized Clay contaminated soil at 7,28 and 90d were respectively 200,300 and 600mg/kg;the"critical content"of solidified/stabilized Clay,CSSM511 and CSSM111 contaminated soil at 28d were respectively 300,200 and 200mg/kg,solidified/stabilized CSSM011 contaminated soil didn’t exist"critical content".The mechanism of CGF solidification/stabilization heavy metal contaminated soil includes the stabilization of heavy metal ions by chemical precipitation,encapsulation,adsorption and ion exchange of the and the stabilization of heavy metal ions by clay mineral in the soil.

关 键 词：固化/稳定化 复合重金属 无侧限抗压强度 浸出浓度 临界含量 作用机理 

分 类 号：X53[环境科学与工程—环境工程]