碱矿渣胶凝材料固化/稳定化铬污染土壤

使用碱激发矿渣胶凝材料固化/稳定化铬污染土壤。通过改变磨细矿渣掺量、碱激活剂的种类以及液固比,处理得到不同的土壤固化体,测定相应的无侧限抗压强度、Cr(Ⅵ)和总Cr的浸出浓度,以研究碱矿渣胶凝材料的固化/稳定化效果及其影响因素。结果表明:随着磨细矿渣掺量增加,土壤固化体强度增加,Cr(Ⅵ)和总Cr的浸出浓度下降。KOH与固体钠水玻璃组合作为碱激发剂时土壤固化体强度较高,浸出浓度较低。土壤液固比过低对降低浸出浓度不利,而过高则降低固化体强度。在碱的激发作用下,当矿渣掺量30%,液固比0.22时,处理后土壤固化体强度高达10MPa,Cr(Ⅵ)和总铬浸出浓度分别从57mg/L和65mg/L降至0.05mg/L和0.2mg/L以下。

STABILIZATION/SOLIDIFICATION OF CHROMIUM-CONTAMINATED SOIL USING ALKALI-ACTIVATED SLAG BINDER

Alkali-activated slag binder was used for stabilization/solidification(s/s) of chromium-contaminated soil Unconfined compressive strength tests and leaching tests were carried out.Slag content,liquid-solid ratio,alkali activator type were varied to investigate their influences on the s/s.The results show that,when slag content was increased,strength of the slag-soil matrixes increased,Cr(Ⅵ) and total Cr leaching concentrations both decreased.Samples activated by both solid sodium silicate and KOH achieved lowest leaching concentrations(both Cr(Ⅵ) and total Cr) and highest unconfined compressive strength.Low liquid-solid ratio played a negative role in decreasing leaching concentrations of Cr(Ⅵ),while higher liquid-solid ratio affected the strength development of the matrix.When the matrixes were prepared with proper slag content(30%),liquid-solid ratio(0.22),Cr(Ⅵ) and total Cr leaching concentrations significantly declined from 57 mg/L and 65 mg/L(raw soil) down to 0.05 mg/L and 0.2 mg/L,and strength of the matrixes increased to 10 MPa.