活化钢渣在固化稳定化工业重金属污染土中的应用

针对钢渣基可持续型固化剂在工业重金属污染土固化稳定化的应用效果进行了试验研究,以重金属固定效率为评价标准,得到了磷酸盐活化钢渣的工艺参数。结果表明,磷酸二氢钾活化可以明显改善钢渣对重金属铅锌镉的固定效果。磷酸二氢钾和钢渣质量比为2%~4%时,通过湿法拌合、20℃风干制得的活化钢渣对重金属铅锌镉的固定效果最佳。并进一步以非活化钢渣作为对比,分析了活化钢渣固化铅锌镉污染土的环境安全及强度特性。结果表明,活化钢渣添加可以显著降低重金属铅锌镉的浸出浓度,提高污染土的pH值。活化钢渣的添加可以提高污染土的无侧限抗压强度,并随着固化剂的掺量的增加而增长;与未活化钢渣相比,钢渣的活化过程会削弱固化土的强度增加,而且固化剂掺加量越大削弱程度越大。

Utilization of activated steel slag to solidify/stabilize industrially heavy-metal contaminated soils

A systematic investigation on the solidification/stabilization effectiveness of industrially heavy-metal contaminated soils by a sustainable steel-slag-based binder (BOFS) is introduced. The activation method of the BOFS is explored, and the heavy-metal immobilization effectiveness is used as an evaluation standard. The results demonstrate that the activation of BOFS with monopotassium phosphate (MKP) can significantly improve the heavy metal immobilization effectiveness. The activated-BOFS (PAB) with a MKP/BOFS ratio of 2%~4% obtained from wet mixing and 20 °C drying is found to possess superior performance. Furthermore, the leaching and strength properties of the PAB-stabilized soils are investigated, and the original BOFS is selected as a control binder for comparison purposes. It is also found that the addition of PAB increases the pH of soils, but reduces the toxicity leaching concentration of Pb, Zn and Cd. Also, the addition of both the original BOFS and PAB increases the unconfined compressive strength (q_u) of the stabilized soils, but the activation of BOFS induces a relatively weaker increase in q_u. Overall, this study demonstrates that the sustainable PAB binder has positive effects on the immobilization of the heavy metals and strength increase of the stabilized soils.