水热法协同处置不同垃圾焚烧炉飞灰及其机理

生活垃圾焚烧飞灰富含重金属且极易浸出对环境造成污染.通过研究流化床飞灰和炉排炉飞灰的理化特性，将流化床飞灰作为硅铝源，将炉排炉飞灰作为碱激发剂，在无添加剂条件下水热合成水钙铝榴石和雪硅钙石，从而将重金属稳定在晶体中.借助SEM图像分析水热合成机理，以雪硅钙石的晶体结构解释其吸附重金属机理.水热反应后液相中几乎不存在重金属，用重金属浸出率对飞灰浸出毒性进行量化评估，水热反应后的飞灰重金属浸出率相比流化床飞灰均有明显的降低，当水热反应添加的流化床飞灰与炉排炉飞灰的质量比为7：3时，水热后的Cd、Cr、Cu、Pb、Zn的浸出率最低，浸出率分别为0.073%、0.006%、0.107%、0.006%、0.326%.

Co-hydrothermal processing for stabilize of different waste incinerator fly ash and its mechanism

MSWI fly ash is rich in heavy metals which is easily leached to pollute the environment. By studying the physical and chemical characteristics of fly ash in fluidized bed and grate furnace, it was found that hibschite and tobermorite could be co-hydrothermally synthesized by the fluidized-bed fly ash and grate-furnace fly ash without any additives. The fluidized-bed fly ash is used as a source of silicon and aluminum while the grate-furnace fly ash is used as an alkali activator. Heavy metals were stabilized in the crystal. The mechanism of hydrothermal synthesis was analyzed based on the hydrothermal products and the surface morphology of fly ash. The mechanism of adsorption of heavy metals was explained by the crystal structure of tobermorite. There was almost no heavy metal in the liquid phase after the hydrothermal reaction. The leaching toxicity of heavy metals was quantitatively evaluated with heavy metal leaching rate. Heavy metal leaching rate of fly ash after hydrothermal reaction was significantly lower than that of fluidized bed fly ash. When the mass ratio of fluidized bed fly ash to grate furnace fly ash added by the hydrothermal reaction was 7:3, the leaching rates of Cd, Cr, Cu, Pb, and Zn after hydrothermal heating were the lowest. The leaching rates were 0.073%, 0.006%, 0.107%, 0.006%, 0.326%, respectively.