[关键词]
[摘要]
对120t/d城市污泥循环流化床焚烧炉飞灰中重金属迁移富集特性进行试验研究,对污泥、飞灰及不同温度、取样点的飞灰中Cr、Mn、Ni、Cu、Zn、As、Cd和Pb 8种重金属迁移富集特性进行了分析。试验结果表明:飞灰、底渣及入炉污泥中主要化学成分为SiO2、Fe2O3、CaO、Al2O3和P2O5,“Si02-CaO-Al2O3-金属氧化物”体系构成了重金属吸附的载体,也为不同形态重金属的吸附提供了活性空间。Cd、As为易挥发性重金属,在炉膛内挥发的Cd、As及其化合物蒸气在503 ℃和475 ℃时几乎全部富集于飞灰颗粒;Cr、Mn、Cu、Zn主要通过夹带富集于飞灰颗粒,它们在尾部烟道不同温度区域飞灰颗粒上的富集程度相当,为难挥发性重金属。
[Key word]
[Abstract]
In order to examine the heavy metals migration and enrichment characteristics, high-temperature fly ash was sampled at the outlet of incinerator and convection heating surface of a 120t/d fluidized bed incinerator for municipal sewage sludge. The sludge characteristics, fly ash behavior and the effect of temperature on Cr, Mn, Ni, Cu, Zn, As, Cd, Pb migration and enrichment in fly ash were studied. Results showed that the main materials of fly ash, bottom ash and sewage sludge were SiO2, Fe2O3, CaO, Al2O3 and P2O5. “SiO2-CaO-Al2O3-metal-oxide” was the carrier of heavy metals in fly ash and provided active space for absorption of different heavy metals. Cd and As were volatile heavy metal. Cd, As and their steam compounds condensed in fly ash particles at 503 ℃ and 475 ℃, respectively. Cr, Mn, Cu and Zn were hard to volatilize and enriched in fly ash particles through entrainment.
[中图分类号]
TK411+.5
[基金项目]
国家科技支撑计划(2012BAA02B01-02)