摘要
隧道窑是工业生产海绵铁的重要方法 .但生产过程温度低,产率不高.按照某隧道窑尺寸,根据相似原理建立了实验室反应罐模型和装料制度.用箱式电阻炉以6℃/min将物料从室温升至1 100℃,保温2 h后快速水冷制得海绵铁样品.实验发现:10～16目时还原度为69.4%,金属化率也最高;通过对10～16目海绵铁样品沿径向取样进行SEM观察,发现颗粒的微观结构差异很大;分析表明微观结构主要影响径向传热和传质,从而导致海绵铁中间还原度最低;内侧铁矿颗粒表面有晶须出现,其生长和发展导致颗粒体积膨胀;外侧铁矿颗粒还原充分,大量失氧和晶须软熔渗透是导致海绵铁外径收缩和烧结的主要原因.
Tunnel is an important method of making sponge iron industrially, but the yield is low because of low temperature and poor dynamics. According to the similar principle and a tunnel kiln size, the laboratory model of retort and the charging system were estab- lished. Materials are heated from room temperature to 1100℃ at the rate of 6 ℃/min in a resistance furnace, with heat persevered for 2 hours, then cooled by running water. It was found that when the degree of reduction is 69.4% ,the rate of metallization is the high- est; the SEM images of sponge iron samples along the radial direction indicate that the microstrnctures of the particles are very differ- ent. Analysis showed that the main effects of microstructures are on the radial heat and mass transfer, resulting in the lowest rate of re- duction at intermediate of sponge iron; whiskers and growth of iron were observed, and the outside of iron ore particles was reduced thoroughly. A large loss of oxygen and whiskers melting and infiltration are the main reasons for the shrinkage and sintering at the outer diameter of sponge iron.
出处
《内蒙古科技大学学报》
CAS
2013年第2期169-172,共4页
Journal of Inner Mongolia University of Science and Technology
关键词
半焦
还原度
金属化率
晶须
semi-coke
reduction degree
metallization degree
whisker
