Effects of alkaline earth oxides on precipitation behavior of metallic iron under CO atmosphere  

作　　者：ZHAO ZhiLong TANG HuiQing ZHANG Ben GUO ZhanCheng 

机构地区：[1]State Key Laboratory of Advanced Metallurgy,University of Science and Technology of Beijing,Beoing 100083,China

出　　处：《Science China(Technological Sciences)》2012年第11期3029-3035,共7页中国科学（技术科学英文版）

基　　金：supported by the National Natural Science Foundation of China and Baosteel (Grant No.50834007);the National Basic Research Program of China (973 Program) (Grant No.2012CB720401)

摘　　要：In gaseous reduction of iron ore fines, alkaline earth oxides have profound effects on the precipitation behavior of fresh metal- lic iron on the particle surface. In this work, in situ observation was performed to reveal the influence of alkaline earth oxides on the precipitation morphology and micro-structure variation of fresh metallic iron from microscopic level by simulation of the gas-solid reaction condition on the surface of ore particles. Experimental results indicate that doping MgO in the particle surface can inhibit the reduction of iron oxide and however doping CaO, SrO and BaO promote; all alkaline earth oxides tested in this study can change the precipitation morphology of fresh metallic iron; minimum doping mole fraction of one oxide to inhibit iron whiskers growth （ NAO ） is related to its cation radius （ r：＋ ） and its extranuclear electronic layers（nAD ）, which can be expressed as NAO = 1.3 × 10^-5r^2AD,√nA^2.

关 键 词：gaseous reduction CO atmosphere in situ observation alkaline earth oxides 

分 类 号：TQ520.1[化学工程—煤化学工程] TG142.31[一般工业技术—材料科学与工程]