基于降解氯源活性的烧结过程二噁英生成抑制技术研究进展

Research Process on Degradating Activities of Chlorine Sources for Inhibiting Dioxin Formation in Sintering Process

高效低成本减少铁矿烧结工序二噁英排放是当前钢铁企业急需解决的重大难题。氯元素作为二噁英生成的必要因素,其活性决定二噁英的生成行为。基于此,首先介绍了烧结过程二噁生成的2种机制,确立了“从头合成”是二噁英生成的主要方式;其次,系统分析烧结料层内氯元素的演化行为,明晰了Cl2、HCl等高活性氯化物的生成机制;在此基础上,介绍了料层内生石灰、石灰石等碱性钙质熔剂和尿素、碳酸肼等含氮阻滞剂对上述高活性氯化物的降解机制及其减排二噁英效果,并对进一步强化料层内抑制二噁英生成提出了展望。本文评述可为钢铁行业减少铁矿烧结工序二噁英排放提供有效参考。

How to cost-effectively reduce dioxins emission of iron ore sintering process is a new challenge for iron and steel industry at present. The activity of Cl element is one of the major factors, which determines the formation of dioxins. In this paper, two formation mechanisms of dioxins in the sintering process were firstly discussed. It was concluded that de novo synthesis was the main path. Then, the evolution behaviors of Cl element in sintering bed were analyzed. The formation mechanisms of high activity chlorides such as Cl2 and HCl were clarified. Moreover, the degradation mechanism of high activity chlorides and the reduction of dioxins emission by alkaline calcium fluxes in sintering mixture such as quicklime/limestone and the nitrogen-containing retarders such as urea/carbohydrazide, were discussed in detail. In addition, the development directions of inhibiting dioxins formation were proposed. This review provides an effective reference for steel industry to reduce dioxins emission in iron ore sintering process.