固化稳定化技术修复汞污染土壤的中试试验研究

Pilot scale study on solidification/stabilization remediation of mercury contaminated soil

以某化工厂内含汞污染土壤为研究对象,进行了固化稳定化技术的中试试验,研究水泥和硫化钠的药剂配比和搅拌方式对处理效果的影响。结果表明,随着水泥添加量增大,汞的浸出浓度大体降低;随着硫化钠添加量的增大,汞的浸出浓度呈现明显上升的趋势;当水泥和硫化钠联用时,浸出液中汞未检出,处理效果较好;搅拌方式对土壤中汞的处理效果影响较小。综合考虑经济成本、处理效果以及增容等因素,建议采用0.05%(质量分数,下同)工业级硫化钠+5.00%复合硅酸盐水泥P.C32.5的药剂配比和挖机铲斗混合搅拌的方式对土壤中的汞进行固化稳定化处理。

Mercury contaminated soil from a chemical plant was selected as the research object. Solidification/stabilization technology was applied for a pilot scale study to explore the treatment effect of reagent ratios of cement and sodium sulfide and stirring methods. The results showed that the concentration of mercury in the leaching solution decreased with the increase of cement content but increased obviously with the increase of sodium sulfide. When cement and sodium sulfide were used together,the mercury concentration in the leaching solution was not detected and the treatment effect was better. Stirring method had little influence on the treatment of mercury in soil. Taking all factors,including cost,treatment effect and compatibilization into consideration, the mixing use of 0.05%(mass fraction) industrial-level sodium sulfide and 5.00%(mass fraction) composite Portland cement (P.C 32.5) with excavator as the stirring tool was highly recommended to application in solidification/stabilization for mercury in the soil.