将废弃鸡蛋壳/碳酸钙作为钙基添加剂,进行飞灰中二恶英的机械化学无害化处理.研究球磨时间、球磨转速对二恶英质量分数和毒性当量降解的影响.利用扫描电镜(SEM)对球磨后样品的结构、尺寸进行分析和表征.实验结果表明,蛋壳作为添加剂可以有效地降解飞灰中的二恶英,通过8h以上的球磨,二恶英的质量分数和毒性当量都降低到50%以下.相同条件下,球磨转速越高,二恶英的降解率也越高.对于规模化的应用,选取转速为300~400r/min较为合理.脱氯反应以及分解反应是机械化学法降解二恶英的主要途径.
The mechanochemical decomposition of the virulent polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in fly ash was studied by the planetary mill. The calcium-based additives such as waste eggshell powder/calcium carbonate were added as the reducing agent. The effects of the milling time and the rotation speed of the ball mill on the degradation efficiency of PCDD/Fs for the total mass fraction and I-TEQ concentration were investigated. The grinding products were characterized with their structure and size by using scanning electron microscope (SEM). Experimental results indicated that by using eggshell powder,more than 50% of the total mass fraction and I-TEQ concentration of PCDD/Fs were reduced when 8 h grinding was conducted. The degradation efficiency increases with an increase in rotation speed,and 300-400 r/min is appropriate for large-scale utilization. The destruction and dechlorination reaction occurred simultaneously in the mechanochemical treatment of PCDD/Fs.