摘要
黏结剂在冷固结球团中必不可少,目前广泛使用的冷固结球团有机、无机黏结剂如CMC、膨润土和水泥等均会在高温下失效,导致球团高温强度严重下降,因此,寻找一种高温强度良好的黏结剂是目前需要解决的问题。采用新型黏结剂制备冷固结球团,通过XRD和SEM-EDS等对新型黏结剂球团制备原料及球团性能特征进行分析,同时探讨黏结剂对球团冷态抗压强度及高温强度的影响及其作用机理。试验结果表明,黏结剂以流动状态存在于冷固结球团中,可有效吸附或包裹铁矿粉颗粒,增加黏结剂配比可同时提高球团的冷态抗压强度及高温抗压强度;在高温还原性气氛下焙烧冷固结球团,由于发生还原反应,球团金属化率提高,铁矿粉颗粒间空隙增大,导致球团强度下降,焙烧时间为30~90 min时,球团金属化率及抗压强度变化趋势最明显;焙烧初期,球团抗压强度不会发生快速下降,且焙烧结束后球团强度仍可保持为100 N/个左右。
Binder is essential in cold-bonded pellets,and currently widely used organic and inorganic binders will lose their strength at high temperatures,resulting in a serious decline in pellets＇ strength,such as CMC,bentonite and cement,etc. Thus,looking for a type of binder which has great high temperature performance is the key problem needed to be solve. Effects of binder,used in this study,on the compressive strength of the pellets at room temperature and high temperature were investigated,XRD and SEM-EDS were used to study the performance of pellets and raw materials,and the mechanism was also discussed. Results show that the binder exists in a flowing state in cold-bonded pellets,which could adsorb or enclose the iron ore particles.The addition of binder ratio could improve the strength of the pellets at room temperature and high temperature.When pellets are roasted under high temperature and reducing atmosphere,metallization ratio of pellets increases for the reduction of pellets,which results in an increase of the interspace between iron ore particles and a decrease of pellets＇ strength. The change of strength and metallization is the most obviously when pellets are roasted for 30-90 min. In the early stage of roasting,strength of pellets does not decrease rapidly as well as pellets using other binders,and pellets could still maintain 100 N/pellet after roasted.
出处
《钢铁》
CAS
CSCD
北大核心
2017年第11期9-14,共6页
Iron and Steel
基金
国家自然科学基金青年基金资助项目(51304014)
高等学校学科创新引智计划资助项目(B13004)
关键词
冷固结球团
新型黏结剂
抗压强度
高温强度
cold-bonded pellets
a new type of binder
compressive strength
high temperature strength
