高浓度含砷污泥的药剂稳定化和水泥固化研究

Study on Solidification and Stabilization of High Concentration Arsenic-containing Sludge

以某铜冶炼厂高浓度含砷污泥为研究对象,分别开展了药剂稳定化和水泥固化小试研究,并对比分析了不同剂量的两种稳定化药剂和矿渣硅酸盐水泥(PSA)单独投加后污泥中砷的浸出毒性。研究发现:该铜冶炼厂污泥中砷含量极高,达到危废级别。对含砷污染土壤具有较好稳定化效果的两种药剂对高浓度含砷污泥的处理效果并不理想,在高剂量投加(15%)条件下仍不能使污泥中砷的浸出浓度低于5 mg/L的危废鉴别标准值。相比而言,传统的水泥固化处置方式能有效降低污泥中砷的浸出浓度,使其低于5 mg/L,但该处置方式污泥增容显著,会增加后续相关处理费用和难度。本研究对开展含重金属污泥和污染土壤的固化/稳定化修复提供了有重要价值的参考和借鉴。

Sludge with high arsenic concentration from a copper smelter is used for bench scale treatability test of 3 stabiliza- tion/solidification reagents（ A, B and PSA） in order to test the treatability of them separately. Reagents were mixed with sludge samples in various percentages in dry weight of the sludge sample and the leachability of arsenic was tested. The results indicate that the initial leachability of arsenic in the sludge sample is above hazardous waste level. Reagent A and B, which are proved to be effective in treating low level arsenic contaminated soil, fail to pass the hazardous waste level of 5 mg/L in arsenic leachability of sludge sample with 15% （d. w. of sludge） reagent. In contrast, the traditional solidification of cement can effectively reduce the leachability of arsenic to less than 5 mg/L. However, this treatment will increase sludge volume and costs for further disposal. This work has generated valuable data and set a foundation for further study in solidification and stabilization of heavy metal con- taminated sludge and soil.