Abstract: The experiment aims to investigate the influence of chlorination agents (NaCl, CaCl₂, and FeCl₃) on volatilization of heavy metals in fly ash from a Shenzhen municipal solid waste incinerator (MSWI) during thermal treatment by using a tube furnace. The results indicate that these three chlorination agents could promote the evaporation of heavy metal in fly ash with different performance. However, these chlorination agents had different effects on the volatilization of heavy metals. All of Pb and Cr could be almost volatilized without addition of chlorination agents, while chlorination agents addition produced significant effect on the volatilization of Zn and Cu: FeCl₃≈ CaCl₂> NaCl. The optimal parameters for vaporization were obtained as follows: fly ash with addition of 15% CaCl₂ was treated at 1000℃ for 2 hours under the condition of N₂ as carrier gas (0.6 L/min).

Key words: fly ash, chlorination agents, heavy metals, evaporation rate

摘要： 以深圳市某垃圾焚烧厂飞灰为原料, 考察高温条件下不同氯化物(NaCl, CaCl₂和 FeCl₃)对飞灰中重金属气化特性的影响规律。结果表明: 3种氯化物均不同程度地促进飞灰中重金属的气化; 对于不同的重金属, 氯化物的影响效果各不相同。在未添加氯化物的情况下, 飞灰中Pb和Cr几乎全部气化。Zn和Cu的气化率受氯化物影响最大, 当添加量均为10% 时, 3种氯化物对Zn和Cu的影响效果为FeCl₃ ≈ CaCl₂ > NaCl。飞灰二次气化的最佳条件: 以0.6 L/min N₂做载气, 添加15%的CaCl₂, 1000℃下高温处理2小时。二次气化过程可减小飞灰毒性, 回收重金属。

关键词: 飞灰, 氯化物, 重金属, 挥发率