基于高炉渣的土壤重金属稳定/固化剂

Soil heavy metal solidification/stabilization agent based on blast furnace slag

通过测定土壤中重金属有效态降低量、正交实验法和扫描电镜方法,研制一种以高炉渣为主要原料的土壤重金属稳定/固化剂。研究结果表明:随着基础配方稳定/固化剂HMS-1的添加量的增加,修复土壤有效态重金属质量分数均降低越多,当HMS-1与土壤的质量比为1:4,液固比为0.28:1 L/kg,室温下养护7 d,有效态锌、镉和铅的质量分数分别降低40.23%,56.68%和48.33%。在HMS-1的基础上,采用正交实验,优化了HMS-1各组分配比,优化后的固化剂命名为HMS-2,即高炉渣、添加剂、石灰石和激发剂的质量分数比等于65:15:2:15。用HMS-2修复土壤,在添加量、液固比、养护温度不变的条件下养护90 d,修复土壤的p H接近原土壤,有水化产物低钙硅质量比的C—S—H凝胶生成,土壤内部结构致密,有利于吸附或共沉淀、包裹和固化重金属,有效态锌、镉和铅的质量分数分别降低了64.08%,66.37%和57.15%。

By means of measuring the reduced amount of available heavy metals in soil, orthogonal test and scanning electron microscope, a new type of soil heavy metal solidification/stabilization agent based on blast furnace slag was developed. The results show that the contents of available heavy metals in soil are lower with the increase of the addition amount of solidification/stabilization HMS-1 and the contents of available Zn, Cd and Pb respectively decrease by 40.23%, 56.68% and 48.33% when the mass ratio of HMS-1 to soil is 1：4, ratio of liquid to solid is 0.28：1 L/kg, temperature is 25 ℃ and curing time is 7 d. The component ratio of HMS-1 is optimized through orthogonal experiment and the optimized curing agent is named as HMS-2, that is to say, the mass fraction rate of blast furnace slag, additive, limestone and activator is equal to 65：15：2：15. When the addition quantity, ratio of liquid to solid and curing temperature is kept unchanged and curing time is 90 d, the p H value of soil treated by HMS-2 is close to that of the original soil, the hydration product of CSH gel with low mass ratio Ca to Si is formed, which makes the internal structure dense and is beneficial to the adsorption or coprecipitation, encapsulation and solidification of heavy metals, and the contents of available Zn, Cd and Pb in soil decrease by 64.08%, 66.37% and 57.15% respectively.