Reseach On The Reduction Kinetics Of Oolitic Hematite With Hydrogen

Reserves of oolitic hematite is very affluent in China, which account for 1/9 the storage quantity of iron ore. It is widely distributed in Hunan, Hubei, Guizhou and other places. With the complexity of mineral itself structure, and the siderite, the oolite chlorite, the phosphate ore occur together with the above-mentioned minerals. At present it has not been fully utilized. Oolitic hematite is considered as one of the most refractory iron ore type. But with the dwindling of high-grade ore mineral resources and foreign iron-ore prices grew increasingly, more and more people set their sights for developing and utilizing the low-grade ore mineral. Oolitic hematite resource reserves of 500 million tons in Guizhou, which mainly located in Hezhang, Kaili area. If that resource can be exploited, it will alleviate the demand for materials such as Shougang Shuicheng Iror and Steel Refco(Group) Co. Ltd. So the research of oolitic hematite has very important significance.The raw material of experiment was oolitic hematite from Hezhang county in Guizhou province, H2 as reducing agent, the influential factors such as reaction temperature, reaction time, additives and other factors were studied on the reduction. The variation factors of mineral powder weightlessness rate, metallization rate, the microstructures were analyzed by means of light microscope, SEM and EDS and chemical composition analysis. The research result shows that the reduction temperature and time have remarkable effect on the metallization rate, metallic iron particles gradually become larger, weightlessness rate and metallization rate of reduced mineral powder is bigger as the temperature increases. The maximums were gained by 24.53% and 83.25% at 120 min under 1100℃, respectively. Oolitic structure was destroyed at 1100 ℃. Reaction rate of oolitic hematite direct reduction is high before 30 min and the rate is largely affected by ferrous oxide concentration in mineral powder. Weightlessness rate and metallization rate of reduced oolitic hematite improved after adding 8.4% CaO, the impurities content of metallic iron is lower. At the same time, the kinetic equation was established under different reaction temperatures, when temperature is 1100℃, R=1.0, reaction rate of oolitic hematite is the fastest, rate equation is V=2.63×10-2CFeO0.93.