Study On Kinetic Of Oolitic Hematite Hydrogen Reduction

Oolitic hematite was a kind of important iron ore resources.However,the reason why the iron ore resources had not been exploited that the complex structure of ore and backward production technology. "Thirteen Five-Year Plan" put forward the concept of green development that try to eliminate backward steel production 100 million tons in next five years. Therefore, the concept of green development has become an important research direction of the metallurgical workers.In this paper Hezhang of Guizhou oolitic hematite were researched for that explore hydrogen direct reduction feasibility with using iron ore magnetic separation process for preparing metallic iron.Firstly aiming at comprehensive utilization of oolitic hematite study mineralogical characteristics of ore,according to the structure of complex features to debelope hydrogen direct reduction-magnetic separation and strengthen calcium oxide reduction of new technology.Secondly, using metallurgical thermodynamics of reaction to analyze feasibility of hydrogen reduction oolitic hematite,on the basis,exploring influence of different factors and combining with magnetic separation technology to achieve metal effective separation of iron and gangue minerals.Finally metallurgical reaction kinetics methods were used to researched hydrogen reduction oolitic restrictive aspects and apparent activation energy. In this paper, chemical analysis, experimental methods of optical microscopy, electron microprobe, XRD and scanning electron microscopy proved the hydrogen reduction reaction mechanism Oolitic. The main conclusions as follows:(1) Oolitic hematite mineralogical characteristics have show that oolitic hematite had complex composition of iron ore mine oolitic structure of the main oolitic concentricring structure with mostly perfect circle or oval shape.Its diffcult ore dressing for that mutual parcel between oolitic and compact structure.(2) Metallurgical thermodynamics of the reaction have show that hydrogen reduction of oolitic hematite complied with the laws of reduction step by step. In iron phase stable region, with the reduction temperature increases the concentration of the reducing agent decrease that iron oxide were reduced under certain hydrogen concentration.(3) Hydrogen reduction of oolitic hematite –magnetic separation process have show that the direct reduction product with metallization rate 95.48% was obtained under the condition of reduction temperature of 1100?, reduction time of 150 min and basicity of 1.5.After magnetic separation, iron grade of 92.14%, iron recovery of 93.15%, phosphorus grade of 0.16%, dephosphorization rate of 90.47% iron concentrate achieved.(4) Hydrogen reduction of oolitic hematite kinetics have show that at temperature of900 ? ~ 1100 ?after several fitting, ore reduction before of 50% was controlled by the chemical reaction and follow reduction controlled by internal diffusion while the reaction rate constant increased with temperature improved.The reaction apparent activation energy was 69.72 KJ / mol. At temperature of 900 ? ~ 1100 ?after several fitting, iron ore basicity of 1.0 before of 50% was controlled by the chemical reaction and followed reduction controlled by internal diffusion while the reaction rate constant increased with temperature improved. The reaction by the process into the internal diffusion reaction time aheader than the ore 5min. The reaction apparent activation energy of reaction 35.43 KJ /mol lower than ore 35.43 KJ / mol that adding Calcium oxide reduced reaction barrier.