复配材料钝化重金属污泥试验及工程应用研究

利用多组分新型高效材料与普通硅酸盐水泥制得复配材料，开展箱涵清淤重金属（Cd、Cr、Cu、Ni、Pb和Zn）污染底泥钝化试验及工程应用研究，采用无侧限抗压强度和毒性浸出浓度评价钝化效果，进一步分析重金属赋存形态变化探讨钝化机制.结果表明，底泥：复配材料：黄沙质量配比为5：4：1时，钝化效果最佳.实际工程应用中，H型和O型固化砖抗压强度分别达10.82和10.11MPa，毒性浸出浓度远低于鉴别标准值（GB5085.3-2007），满足资源化应用要求.重金属浸出浓度与离子交换态和有机结合态占比呈正相关，有机结合态和铁锰氧化态分别为底泥和固化砖中重金属的主要赋存形态，二者占比在固化前后呈现完全相反的变化趋势，该变化对固化稳定化重金属起重要作用.除H型Cr外，其他固化砖中重金属残渣态占比均有所增加.该复配材料基于多组分物质间相互协同作用实现重金属钝化具有实际应用前景.

Experiments and engineering application research on passivation of heavy metal contaminated sediment by compound material

Experiments and engineering application study on passivation of heavy metal (Cd, Cr, Cu, Ni, Pb and Zn) contaminated sediment in box culvert had been carried out, the passivating agents was consist of multi-component new high-efficiency materials and ordinary silicate mud. Unconfined compressive strength and toxic leaching concentration were studied to evaluate the stabilization effect, and the changes in the forms of heavy metals were further analyzed to explore the passivation mechanism. The results indicated that when mass ratio of sediments, compound materials and sand was 5:4:1, the passivation effect was the best. In practical engineering applications, the compressive strength of H-type and O-type cured bricks reached 10.82 and 10.11MPa respectively, and toxic leaching concentration of heavy metals was far lower than the identification standard value (GB5085.3-2007), which met the requirements of resource application. The leaching concentration of heavy metals was positively correlated with the proportions of ion exchange state and organic bond state proportions. Organic bond state and iron-manganese oxidation state were the main forms of heavy metals in sediments and solidified bricks respectively, which showed a completely opposite trend after solidification. This change played an important role in passivating heavy metals. Except for H-type Cr, the proportion of residual state in other cured bricks had all increased. This kind of compound material which based on multi-component interaction had a application prospect in passivation of heavy metals.