城市生活垃圾焚烧底灰的水热固化研究

Hydrothermal solidification of municipal solid waste incineration bottom ash

利用水热技术对城市生活垃圾底灰进行资源化利用研究,将其固化为一种强度高、重金属溶出少的建筑材料。主要研究了添加消石灰固化生活垃圾底灰的硬化机理,并且为了100%利用垃圾焚烧灰,也研究了添加垃圾飞灰固化底灰的方法。同时还进行了重金属浸出试验,测试固化体中重金属溶出量。研究结果表明,托勃莫来石晶体的生成是影响固化体强度的主要原因,而且托勃莫来石的生成量越多,样品的强度越高。飞灰也可以作为一种固化添加剂对底灰进行水热固化,且添加飞灰的硬化机理和消石灰相同。经过水热固化,固化体的重金属溶出量可大大降低。水热技术有望成为一种城市生活垃圾底灰资源化利用的有效方法。

Solidification of municipal solid waste incineration （MSWI） bottom ash into a building material with high strength and less heavy metal dissolution has been carried out using a hydrothermal processing method. The hardening mechanism of hy- drothermal solidification of MSWI bottom ash by adding slaked lime was investigated in this study. Moreover, leaching tests were also conducted to determine the amount of heavy metals dissolved from the solidified specimens. The experimental results showed that the strength development of the solidified specimens with slaked lime addition was due primarily to the tobermorite formation and the more the tobermofite formed, the higher the strength was. MSWI fly ash also could be used as an additive to solidify bot- tom ash,and the hardening effect of solidification was favored to be similar to that with slaked lime addition. Under the bydrother- real processing, the amount of heavy metals dissolved from the solidified specimens was reduced greatly. As such,the hydrothermal processing may have a high potential for recycling MSWI bottom ash.