粉煤灰碳热氯化机制的界面反应

采用碳热氯化工艺从粉煤灰中提取铝、铁和硅并制备高值氯化产品，研究了氯化温度、氯化时间、炭种类、焦炭量、原料粒度的变化对粉煤灰碳热氯化过程的影响，分析了粉煤灰碳热氯化机制可能发生的四种界面反应情况。结果表明：氯化温度对粉煤灰氯化过程的影响较大，温度越高，粉煤灰中铝、铁和硅的氯化效果越好；粉煤灰中铝、铁和硅的氯化速度前期较快，30 min后氯化率增长缓慢；不同类型的炭对粉煤灰中铝、铁和硅的氯化率影响也较大，活性炭的氯化效果最好；随着焦炭量的增大，铝、铁和硅的氯化率逐渐提高，焦炭量增加至30%后，氯化率变化不大；粉煤灰和焦炭的粒度越细，粉煤灰的氯化效果越好；粉煤灰碳热氯化可能发生四种界面反应情况，第一种需要炭表面有足够的反应活性位点，同时炭活性位点距氧化物的间距要小于催化产生的活性氯原子消失殆尽的距离；第二种需要氧化物与炭接触，且炭表面没有可产生气态氯原子的活性位点；第三种需要炭上没有活性位点，且氧化物与炭的间距小于某极限距离；第四种需要Al₂O₃、Fe₂O₃或SiO₂颗粒与炭的距离...

Interfacial Reaction of Carbochlorination Mechanism of Fly Ash

Carbochlorination process is used to extract aluminum, iron and silicon from fly ash to prepare high-value chlorinated products in this paper. The effects of changes in chlorination temperature, chlorination time, carbon type, coke content and particle size of raw materials on carbochlorination process of fly ash were studied. The results show that the chlorination temperature has a greater influence on the chlorination process of fly ash. The higher the temperature, the better the chlorination effects of aluminum, iron and silicon in fly ash. The chlorination rate of aluminum, iron and silicon in fly ash is faster in the early stage, and the chlorination rate increased slowly after 30 min. Different types of carbon also have a greater impact on the chlorination rate of aluminum, iron and silicon in fly ash. Because activated carbon has a larger specific surface area and void structure, activated carbon has the best chlorination effect. As the coke content increases, the chlorination rate of aluminum, iron and silicon gradually increases, and the chlorination rate does not change much after 30%. The finer the particle sizes of fly ash and coke, the better the chlorination effect. When the particle size of fly ash and coke is below 400 mesh, the chlorination rates of iron, aluminum and silicon are 91%, 88% and 41%, respectively.