城市固体废弃物焚烧 (Municipal Solid Waste Incineration,简称MSWI) 飞灰作为一种危险废弃物，通过合理手段进行资源化处理一直是研究热点，近年来用城市固体废弃物焚烧飞灰进行碳酸化反应封存CO₂受到广泛关注，系统分析了城市固体废弃物焚烧飞灰碳酸化处理研究现状。首先简述了固体废弃物焚烧飞灰成分及处理方式,其主要成分包括CaO、SiO₂、Al₂O₃和可溶性Na、K盐以及重金属等，目前主要通过水泥固化法、熔融固化法和化学药剂处理法等方法处理。阐述了碳酸化反应机理，从飞灰组分对固碳率的影响方面对固体废弃物焚烧飞灰隔离CO₂潜力进行了介绍；然后分析了固体废弃物焚烧飞灰碳酸化反应的影响因素，包括反应温度、液固比、反应气氛、CO₂体积分数、反应压力、粒度、反应时间以及工艺条件等，结果表明，不同反应条件对温度和CO₂体积分数要求差异较大，液固比在0.3左右为最优，反应气氛中SO₂的存在会阻碍反应正向进行，反应压力不影响碳酸化平衡，但是其在整个动力学过程中起重要作用，粒度过大或过小均不利于反应，碳酸化反应速率会随反应时间增加逐渐降低，液相反应优于气固直接碳酸化反应。介绍了固体废弃物焚烧飞灰碳酸化反应过程模型，包括浸出—沉淀模型、缩核模型和表面覆盖模型，分析了碳酸化反应动力学模拟结果，结果表明水量的多少决定了相界面反应与扩散作用的相对强度。最后分析了固体废弃物焚烧飞灰碳酸化反应对重金属和可溶性盐浸出行为的影响，展望了碳酸化处理城市固体废弃物焚烧飞灰潜在应用前景与挑战，为固体废弃物焚烧飞灰碳酸化处理提供借鉴。

Municipal solid waste incineration (MSWI) fly ash，as a kind of hazardous waste, has been a research hotspot for resource treatment by reasonable means. The carbonation of MSWI fly ash for CO2 storage has been widely concerned in recent years. In this paper, the status of carbonation treatment of MSWI fly ash was systematically analyzed. Firstly, the composition and treatment methods of MSWI fly ash were briefly described. The main components include CaO, SiO2, Al2O3, soluble Na/K salts and heavy metals, etc. At present, they are mainly treated by cement solidification, melting solidification and chemical treatment. The carbonation reaction mechanism was described. The potential of CO2 isolation from fly ash was introduced from the aspect of the influence of fly ash components on carbon fixation rate. Then, the influencing factors of the carbonation reaction of MSWI fly ash were analyzed, including reaction temperature, liquid-solid ratio, reaction atmosphere, CO2 volume fraction, reaction pressure, particle size, reaction time and process conditions, etc. It is concluded that: different reaction conditions have different requirements for temperature and CO2 volume fraction, the liquid-solid ratio is generally about 0.3, the existence of SO2 in the reaction atmosphere hinders the reaction forward. The reaction pressure doesn′t affect the carbonation equilibrium, but it plays an important role in the whole process kinetics. Too large or too small particles are unfavorable to the reaction. The carbonation rate decreases with time, and the liquid-phase reaction is better than the gas-solid direct carbonation. The carbonation process model of MSWI fly ash, including leaching-precipitation model, shrinking core model and surface covering model was introduced. The simulation results of carbonation reaction kinetics were analyzed. The results show that the relative strength of interfacial reaction and diffusion depends on the amount of water. Finally, the influence of carbonation reaction on heavy metal and soluble salt leaching behavior of MSWI fly ash was analyzed. The potential application prospect and challenge of carbonation treatment of municipal solid waste incineration fly ash were prospected, so as to provide a way for the carbonation treatment of fly ash from solid waste incineration.

0 引言

1 固废焚烧飞灰碳酸化隔离CO2潜力

   1.1 固废焚烧飞灰组成及处理方法

   1.2 固废焚烧飞灰碳酸化反应机理

   1.3 固废焚烧飞灰固碳率与钙含量关系

2 固废焚烧飞灰碳酸化的影响因素

   2.1 反应温度

   2.2 液固比

   2.3 反应气氛

   2.4 CO2体积分数

   2.5 反应压力

   2.6 粒度

   2.7 反应时间

   2.8 工艺条件

3 固废焚烧飞灰碳酸化隔离CO2模拟

4 重金属与可溶性盐浸出行为

5 结语与展望