含锌冶金尘泥还原烟气沉积特性

Sediment of flus gas in direct reduction treated by zinc-bearing metallurgical dust

含锌烟气沉积堵塞是制约转底炉处理冶金尘泥生产的关键所在.采用高温管式炉模拟冶金尘泥球团还原产生的含锌烟气沉积试验,对沉积物的质量分布、形貌及主要组分等沉积特性进行分析,研究了温度、碱金属及烟气气氛对烟气沉积的影响.研究结果表明,温度对烟气沉积特性影响显著,烟气沉积过程从950~1 000℃开始,在600~750℃达到最大沉积量,温度低于600℃后沉积逐渐结束,并且沉积物晶粒尺寸随温度降低逐渐减小,析出物混乱度逐渐增大;沉积富集区域烟尘锌质量分数为58.50%~65.23%,沉积物主要物相为ZnO、NaCl、KCl和Zn5（OH）8Cl2H2O,碱金属氯化物在沉积富集区的物态变化促进了烟尘颗粒的相互聚集、团聚;烟气的氧化性不足,使布袋除尘灰中还存在大量单质锌.

The blocking by zinc-bearing flue gas is the key of restraining the treatment of metallurgical dust in rotary hearth furnace. In the current study,the high-temperature tubular furnace was used to mimic the deposition of flus gas sed-iment produced by the reduction reaction of metallurgical dust,then,the characteristics of depositions including the distri-bution of quality,the morphology and the main components of depositions were analyzed,the effects of temperature,al-kali metal and tail gas atmosphere on the characteristics of flus gas sediment were also studied here. The results showed the deposition started from 950-1 000℃,with the maximum amount of deposition reached at 600~750℃and ended un-der 600℃indicating that the temperature had a significant influence on the characteristics of flus gas sediment. In addi-tion,the lower temperature decreased the size of deposite and increased of the chaos of deposite. The main phase in the enrichment region of dust disposition was composed of ZnO,NaCl,KCl and Zn5（OH）8Cl2H2O,in which the zinc content was 58.50%-65.23%. The state change of the alkali metal chloride in enrichment region promoted the accumulation and re-union of dust particles. Due to the weak oxidation of flue gas,a large amount of metallic zinc appeared in the bag dust.