In situ observation of reduction behavior of hematite with solid carbon and crystallographic orientation between hematite and magnetite

被引:21
作者
Kashiwaya, Yoshiaki
Yamaguchi, Yasuhide
Kinoshita, Hiroshi
Ishii, Kuniyoshi
机构
[1] Hokkaido Univ, Grad Sch Engn, Kita Ku, Sapporo, Hokkaido 0608628, Japan
[2] Hokkaido Univ, Grad Sch Engn, Sapporo, Hokkaido 060, Japan
关键词
direct reduction; iron oxides; EBSP; crystallographic orientation; carbon composite;
D O I
10.2355/isijinternational.47.226
中图分类号
TF [冶金工业];
学科分类号
0806 ;
摘要
Recently, the composite pellets between iron ore and carbon are studied by many researchers because of its high reactivity. However, the reaction mechanism of the composite pellet is not yet clarified. It is obviously determined the reaction mechanism at initial stage as the direct reaction between solid carbon and iron oxide. However, in the course of reaction, the reaction mechanism will change to the indirect reduction of iron oxide with CO gas owing to the separation of the interface between solid carbon and iron oxide. In this study, samples of polycrystalline hematite (grain size was approximately 20 mu m) were prepared. The hematite sample was coated by carbon with different thickness. The in situ observation by a laser microscope was carried out. The crystal orientation and morphology was investigated before and after the reaction using EBSP, SEM, AFM, XRD and Raman. The direct reduction began from about 650 degrees C and the reaction proceeded rapidly until carbon was consumed. The behavior of reduction was different from the thickness of carbon layer (amount of carbon) which was related to whether the product gas (CO) could be passed through the carbon layer or not. After reduction, the lath magnetite having same direction was a grain was observed on the surface. The crystallographic orientation between magnetite and hematite was as follows; (0001)(H) vertical bar vertical bar (111)(M), [1100](H) vertical bar vertical bar [110](M) In addition, the growth direction of the lath magnetite formed on the hematite surface was [2130](H) vertical bar vertical bar [101](M).
引用
收藏
页码:226 / 233
页数:8
相关论文
共 17 条
[1]   STRUCTURAL-CHANGES AND KINETICS IN GASEOUS REDUCTION OF HEMATITE [J].
BRADSHAW, AV ;
MATYAS, AG .
METALLURGICAL TRANSACTIONS B-PROCESS METALLURGY, 1976, 7 (01) :81-87
[2]  
BRILLEDW.H, 1965, J IRON STEEL I, V203, P361
[3]   THE INFLUENCE OF SPECIFIC IMPURITIES ON THE NUCLEATION AND GROWTH OF MAGNETITE DURING REDUCTION OF ARTIFICIALLY PREPARED HEMATITE [J].
CHAIGNEAU, R ;
HEEREMA, RH .
METALLURGICAL TRANSACTIONS B-PROCESS METALLURGY, 1991, 22 (04) :503-511
[4]   HEMATITE SINGLE-CRYSTAL REDUCTION INTO MAGNETITE WITH CO-CO2 [J].
ETTABIROU, M ;
DUPRE, B ;
GLEITZER, C .
METALLURGICAL TRANSACTIONS B-PROCESS METALLURGY, 1988, 19 (02) :311-317
[5]  
HAMAGUCHI H, 1994, RAMAN SPECTROSCOPY, P180
[6]   MICROSTRUCTURAL CHANGES ON THE REDUCTION OF HEMATITE TO MAGNETITE [J].
HAYES, PC ;
GRIEVESON, P .
METALLURGICAL TRANSACTIONS B-PROCESS METALLURGY, 1981, 12 (03) :579-587
[7]   MORPHOLOGY OF HEMATITE TO MAGNETITE REDUCTION ZONE [J].
JANOWSKI, J ;
WYDERKODELEKTA, M ;
SADOWSKI, A ;
DELEKTA, J .
STEEL RESEARCH, 1995, 66 (04) :135-139
[8]   Evolution of porosity profiles of magnetite phase during high temperature reduction of hematite [J].
Janowski, J ;
Baranski, A ;
Sadowski, A .
ISIJ INTERNATIONAL, 1996, 36 (03) :269-278
[9]  
Janowski J, 1996, IRONMAK STEELMAK, V23, P479
[10]   Characteristics of nano-reactor and phenomena during mechanical milling of hematite-graphite mixture [J].
Kashiwaya, Y ;
Suzuki, H ;
Ishii, K .
ISIJ INTERNATIONAL, 2004, 44 (12) :1975-1980