铁矿烧结过程烟气中微细颗粒污染物的特性

Characteristics of fine particle pollutant in flue gas of iron ore sintering process

铁矿烧结过程分为点火段、中间段(点火结束至烟气温度升温前)和升温段(烟气温度开始上升至达到最高温)3个阶段,通过烧结杯模拟实验研究了各阶段烟气中微细颗粒污染物的排放浓度及其特性。研究结果发现,点火段、中间段微细颗粒污染物的质量浓度较低,在升温段则显著上升;各阶段切割粒径d50=0.7μm粒级颗粒表面形貌也存在着差异,其中点火段和中间段的颗粒主要是由球形颗粒组成,颗粒轮廓清晰没有明显的聚结现象,而升温段d50=0.7μm粒级颗粒主要为不规则的絮状体,颗粒之间易聚结形成团聚状;升温段d50=0.7μm粒级颗粒中F、S、K、As、Pb元素的含量明显高于点火段和中间段的含量,而Fe元素则在点火段和中间段的含量较高,在升温段含量相对较低。

Sintering process was divided into three stages：ignition stage,middle stage（from the ending point of ignition to rising point of flue gas temperature）and flue gas temperature rising stage.The emission concentrations of fine particles and the characteristics of each stage were studied by sinter pot test.The results show that the emission concentration of fine particles during ignition stage and middle stage is relatively low,while it achieves a significant increase during the flue gas temperature increasing stage.Besides,the fine particles d50=0.7μm from the three sintering stages have different surface morphologys.The fine particles d50=0.7μm from the ignition period and middle stage mainly consist of spherical particles without agglomerating phenomenon while the fine particles from flue gas temperature increasing stage consist of random-shaped aggregation,in which the obvious phenomenon of agglomeration is found.The contents of elements like F,S,K,As,and Pb in the fine particles from the flue gas temperature increasing stage are the highest,but the content of Fe is the lowest comparing to the other stages.