| The high chromia vanadium-titanium magnetite is a symbiotic compound mineral including Fe, V, Ti, Cr and other elements, which has a very high comprehensive utilization value. Vanadium and titanium are recognized as the world's strategic metals, widely used in aerospace, marine, medical, telecommunications and other fields. At the same time, China will face the depletion of chromium resources. So it is urgently needed to solve the issue of our long-term demand for chromium resources. Smelting vanadium-titanium magnetite by blast furnace is still an important mean and pathway to achieve the comprehensive utilization. However, there are no relative researches about smelting high chromia vanadium-titanium magnetite by blast furnace in home and abroad. The relevant studies show that the reduction reactions of vanadium and titanium oxide occur in the cohesive zone of BF. Therefore, it is necessary to ascertain the transfer mechanism of valuable components in cohesive zone when smelting high chromia vanadium-titanium magnetite in the condition of BF process.Therefore, this study explored the preparation process of oxide pellet added 40% high chromia vanadium-titanium magnetite firstly. Second the cohesive dropping characteristics of three different burdens structures including pellet, sinter and mixed burden that the ratio of pellet is 33.65%were investigated. Based on the above, the migration mechanism of valuable components in cohesive dropping zone and the contents of valuable components in dropping iron as well as the phase compositions in not dropping substance were researched. Finally, the migration mechanism of valuable components was analyzed in theory from the view of thermodynamic.By this study, the following conclusions can be gained:(1) The pellet added 40% high chromia vanadium-titanium magnetite was roasted at 1275 ? with 20 minutes. Its crushing strength is 2582 N, which can meet the quality requirements for blast furnace production.(2) Considering the two indicators of distribution of the cohesive dropping zone and permeability resistance, the cohesive dropping characteristics of mixed burden structure are the best. It starting melting temperature, dropping temperature and maximum pressure were 1245.1?,1376.4?, and 15527 Pa.(3) The valuable components migration mechanism of pellet and mixed burden in cohesive dropping zone is consistent. The migration process of iron is Fe2O3?Fe3O4?FeO ?Fe, at the same time, the generated FeO will generate 2FeOSiO2 with SiO2; The migration process of titanium is Fe2O3-3TiO2? 2FeOTiO2?FeO·TiO2?Ti(O0.19C0.53N0.32)?. Ti(Co.7No.3)?Ti(C,N)?[Ti]; The migration process of vanadium is V2O3?VN,VC?[V]; The migration process of chromium is (Feo.6Cro.4)2O3?FeCr2O?[Cr].(4) By thermodynamic calculations show that titanium oxide reduction process will produce Ti3O5,TiC and TiN and the reduction process of Fe2TiO5?Fe2TiO4?FeTiO3 is easy; Vanadium oxide reduction process will be VN ?VC ?VO; Chromium oxide can be reduced to Cr which will form a continuous solid solution with liquid iron; Ferric oxides are deoxidized according to the theory of Gradual Deoxidizing. |
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