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Decomposition of PCDD/Fs by mechanochemical means with
calcium-based additives |
| WEI Ying-lei, YAN Jian-hua, LU Sheng-yong, LI Xiao-dong |
| State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China |
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Abstract 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 ITEQ 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 300400 r/min is appropriate for largescale utilization. The destruction and dechlorination reaction occurred simultaneously in the mechanochemical treatment of PCDD/Fs.
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Published: 19 March 2012
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钙基添加剂对机械化学法降解二恶英的影响
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8 h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300～400 r/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.
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