Zhu Zhicheng, Huang Yaji, Yu Mengzhu, Cheng Haoqiang, Li Zhiyuan, Xiao Yixuan, Xu Wentao
Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, China.
Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, China.
J Hazard Mater. 2024 Apr 15;468:133699. doi: 10.1016/j.jhazmat.2024.133699. Epub 2024 Feb 3.
Chlorine has been proven to promote the volatilization of heavy metals during sludge combustion. This work compared the migration of heavy metals with NaCl addition under different combustion modes at 900 ℃. The combustion modes have less effect on the mineral phase of residues, but the volatilization and toxicity reduction of heavy metals were more pronounced under isothermal combustion. The mineral evolution, release of Cl, and migration of metals were dynamically tracked by the continuous sampling at different combustion time under isothermal combustion. It was found that the volatile matter and fixed carbon burned almost simultaneously, and the addition of NaCl promoted them. As combustion proceeded, the minerals gradually crystallized and the heavy metals were volatilized due to the direct and indirect chlorination. Meanwhile, the chlorination and volatilization of Zn was less than that of Pb due to its effective solidification by minerals. The combination of the adsorption by exposed char and solidification by sludge minerals influenced the dynamic leaching behavior of metals. These results will help understand the interactions between heavy metals, inorganic Cl, and Fe-Si-Al minerals during combustion, which will further help optimize the combustion strategy for both stabilization or enrichment of heavy metals when inorganic chlorine exists.
已证实氯可促进污泥燃烧过程中重金属的挥发。本研究比较了900℃下不同燃烧模式下添加NaCl时重金属的迁移情况。燃烧模式对残渣的矿物相影响较小，但在等温燃烧条件下重金属的挥发和毒性降低更为明显。通过在等温燃烧条件下不同燃烧时间的连续采样，动态跟踪了矿物演化、氯的释放和金属的迁移。结果发现，挥发物和固定碳几乎同时燃烧，添加NaCl促进了它们的燃烧。随着燃烧的进行，矿物逐渐结晶，由于直接和间接氯化作用，重金属挥发。同时，由于锌被矿物有效固化，其氯化和挥发程度低于铅。暴露焦炭的吸附作用与污泥矿物的固化作用相结合，影响了金属的动态浸出行为。这些结果将有助于理解燃烧过程中重金属、无机氯和铁硅铝矿物之间的相互作用，进而有助于优化无机氯存在时重金属稳定化或富集的燃烧策略。
