铅污染废弃黏土在水热条件下的固化/稳定化规律和机理探究 English Version
Exploration of the Solidification/Stabilization Law and Mechanism of Lead-Contaminated Abandoned Clay under Hydrothermal Condition
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摘要: 铅是废弃黏土中常见的重金属污染物，通过水热技术将铅污染废弃黏土固化/稳定化处理，有望实现铅离子的高稳定化。本文开展了水热条件下（200℃、12h）不同铅含量废弃黏土固化/稳定化试验，研究Pb2+稳定化机理及对固化体强度、体积密度、吸水等性能的影响规律。结果表明：经水热反应后各含量Pb2+的稳定率均达到99%以上，其稳定化主要通过生成CaPb(OH)4、Pb(OH)2、PbO化合物实现。水热反应显著提高了固化体强度，抗压强度较常温反应28天提高约3倍，但Pb2+小幅度降低了试件强度，这可能与Pb2+抑制了托勃莫来石、硬硅钙石的生成有关。Abstract: Lead is a common heavy metal pollutant in abandoned clay. Stabilizing lead - contaminated waste clay through hydrothermal technology is expected to achieve high - level stabilization of lead ions. This paper carried out experiments on the solidification / stabilization of waste clay with different lead contents under hydrothermal conditions (200℃, 12h), and studied the stabilization mechanism of Pb2+ and its influence on the compressive strength, bulk density, water absorption and other properties of the solidified specimens. The results show that the stability rate of Pb2+ over 99%, and its stabilization is mainly achieve through the generation of compounds such as CaPb(OH)4, Pb(OH)2, PbO. The hydrothermal reaction greatly improves the strength of the specimen, which is about three times higher than that of curing at room temperature for 28 days. But lead slightly reduces the strength of the specimen. This may be related to the inhibition of Pb2+ on the formation of tobermorite and xonotlite.
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