Chlorine Migration in the Calcination Process of Washed Fly Ash from Municipal Solid Waste Incinerator
We proposed a new sound recycling system for fly ash, washing, calcinating and changing the treated fly ash into the raw material in cement industry (WCCB). Calcinating process is to reduce the chlorine in the residue once more following washing process, as cement industry has very strict limitation for chlorine. Another purpose is to stabilize the treated residue. We tried three kinds of fly ashes: raw fly ash from the boiler or economizer of incineration system (RFA), fly ash collected in bag filter with the injection of Ca(OH)2 for acid removal (CaFA) and fly ash collected in bag filter with the injection of NaHCO3 for acid removal (NaFA). Based on the washing experiments results, we have chosen a relatively acceptable washing condition (the 1st step: Liquid (ml) /solid (g) ratio=3, Mixing time=5 min, Mixing speed=150 rpm; the 2nd step: L/S=3, Mixing time=10min, Mixing speed=150 rpm). We used the washed residue of the three kinds of fly ashes in the calcinating experiments. We varied the heating temperature from 400 to 1100 , and we tried ℃ ℃ different atmosphere, 100% N2 and 10% O2 (90% N2 for balance), with different flux, 25 ml/min, 50 ml/min and 75 ml/min. It was found that the condition of heating temperature at 1000 , heating time at 1 hour, dwell ℃ time at 1 hour and the atmosphere as 10% O2 (90% N2 for balance) could be the most suitable for calcinating process. Under that condition, 91% chorine from washed residue of RFA, 52% chlorine from washed residue of CaFA and 96% chlorine from washed residue of NaFA could be reduced. In all under the chosen condition for WCCB system, 98.9% chlorine in RFA, 94.0% chlorine in CaFA and 99.8% chlorine in NaFA can be removed.
Fen-fen ZHU Masaki TAKAOKA Kazuyuki OSHITA Shinsuke MORISAWA Hiroshi TSUNO
School of Environment & Natural Resources, Renmin University of China, Beijing, China Dept.of Environmental Engineering, Kyoto University, Kyoto, Japan
国际会议
The Fifth International Conference on Waste Management and Technology(第五届固体废物管理与技术国际会议)
北京
英文
524-527
2010-11-01（万方平台首次上网日期，不代表论文的发表时间）