Jin Lei, Huang Guodong, Li Yongyu, Zhang Xingyu, Ji Yongsheng, Xu Zhishan
School of Civil Engineering and Construction, Anhui University of Science and Technology, No 168, Taifeng Road, Huainan 232001, China.
School of Energy and Safety, Anhui University of Science and Technology, No 168, Taifeng Road, Huainan 232001, China.
Materials (Basel). 2021 Apr 12;14(8):1927. doi: 10.3390/ma14081927.
Setting time and mechanical properties are key metrics needed to assess the properties of municipal solid waste incineration (MSWI) bottom ash alkali-activated samples. This study investigated the solidification law, polymerization, and strength development mechanism in response to NaOH and liquid sodium silicate addition. Scanning electron microscopy and X-ray diffraction were used to identify the formation rules of polymerization products and the mechanism of the underlying polymerization reaction under different excitation conditions. The results identify a strongly alkaline environment as the key factor for the dissolution of active substances as well as for the formation of polymerization products. The self-condensation reaction of liquid sodium silicate in the supersaturated state (caused by the loss of free water) is the major reason for the rapid coagulation of alkali-activated samples. The combination of both NaOH and liquid sodium silicate achieves the optimal effect, because they play a compatible coupling role.
凝结时间和力学性能是评估城市固体废弃物焚烧（MSWI）底灰碱激发样品性能所需的关键指标。本研究探讨了添加NaOH和水玻璃时的固化规律、聚合反应及强度发展机制。利用扫描电子显微镜和X射线衍射确定了不同激发条件下聚合产物的形成规律及潜在聚合反应的机理。结果表明，强碱性环境是活性物质溶解及聚合产物形成的关键因素。水玻璃在过饱和状态下（由自由水损失引起）的自缩聚反应是碱激发样品快速凝结的主要原因。NaOH和水玻璃共同作用可达到最佳效果，因为它们起到了协同耦合作用。
