生活垃圾焚烧飞灰典型组分对其熔融特性的影响

Effects of Typical Components of MSWI Fly Ash on Its Melting Characteristics

以天津某生活垃圾焚烧厂飞灰为研究对象,通过额外添加典型组分的方法,研究了飞灰熔融特性的变化规律,并给出了碱度与最低流动温度的优选区间和玻璃化产品的质量验证。结果表明:SiO_(2)和Al_(2)O_(3)都能有效降低飞灰的熔融特征温度,SiO_(2)强于Al_(2)O_(3);CaO和MgO能提升飞灰的熔融特征温度,CaO提升的较大;Fe_(2)O_(3)、Na_(2)O和K_(2)O能显著降低飞灰的变形温度,降低幅度达到了100℃左右,但对其他特征温度的影响不大。为了降低飞灰熔融的能耗,添加SiO_(2)调节飞灰碱度能最有效地降低流动温度。碱度区间在0.64~1.45时,飞灰的流动温度降低了140℃以上,分布在1250~1300℃。优选碱度为1.45时,玻璃化产品中玻璃体的含量接近100%,毒性鉴别结果远低于GB 5085.3—2007设定的限值。

Taking the fly ash from a MSWI plant in Tianjin as the research object,the variation of fly ash melting char-acteristics was studied by adding additional typical components,and the optimum range of alkalinity and minimum flow temper-ature was given,as well as the quality verification of vitrified products.The results showed that both SiO_(2) and Al_(2)O_(3) could effectively reduce the melting characteristic temperature of fly ash,and SiO_(2)was better than Al_(2)O_(3).CaO and MgO could increase the melting characteristic temperature of fly ash,and CaO could increase more.Fe_(2)O_(3),Na_(2)O and K_(2)O could significantly reduce the softening temperature of fly ash,with the reduction of about 100℃,but have little effect on other characteristic temperatures.In order to reduce the energy consumption of fly ash melting,added SiO_(2) to adjust fly ash alkalinity could most effectively reduce the flow temperature.When the alkalinity range was between 0.64 and 1.45,the flow temperature of fly ash decreased by more than 140℃,which distributed between 1250℃and 1300℃.When the optimum alkalinity was 1.45,the content of vitreous in vitrified products was close to 100%,and the toxicity identification result was far lower than the limit value set in GB 5085.3—2007.