碳化对水泥固化重金属污染土的作用研究

Research on Carbonation Effect on OPC-solidified Heavy Metal Contaminated Soil

本文基于一组室内试验对碳化在水泥固化重金属废弃物过程中的作用进行了研究。所采用重金属废弃物,经过不同含量普通波特兰水泥(OPC)固化处理后,分别在N2、空气和CO2环境中养护28d,通过一系列化学反应将土样碳化,测试它的强度、微观结构变化和重金属离子溶出特性。试验结果表明:与空气环境中养护相比,碳化作用增加了固化产物的强度,减少了重金属析出量,N2环境中水泥水化作用延迟,固化产物最终强度降低,但重金属析出量减小。

Based on a series of experiments, effects of carbonation on a cement solidified heavy metal polluted soil materials were reported. The polluted soil was mixed with different amounts of ordinary Portland cement ( OPC) and cured in three different environments: nitrogen, lab air and carbon dioxide for 28 days. Soil samples were carbonized by a series of chemical reactions. Its strength, microstructure change and heavy metal ion dissolution characteristics were tested. The results indicated that carbonation enhanced the strength of solidified products and reduced the precipitation of heavy metal with comparing to lab air-cured samples. Samples cured in nitrogen showed retardation phenomenon of OPC hydration, resulting in low UCS value, and low precipitation of heavy metals.