Experimental Study On Oxidized Pellets Preparation Of Imported High Chromia Vanadia-Titania Magnetite

In order to meet the need of iron ore raw materials and develop high additional value vanadia and chromia products, relying on regional advantage, an iron and steel company of our country expands iron ore resources source actively, and imports large quantities of high chromia vanadia-titania magnetite for the blast furnace production every year. Compared to the ordinary vanadia-titania magnetite, the mineral composition of high chromia vanadia-titania magnetite is more complicated and the raw material speciality is special. Preliminary studies have shown that, to guarantee good metallurgical properties of sinter, the ratio of high chromia vanadia-titania magnetite in sintered iron materials should be less than15%. In accordance with the company’s existed burden structure, to achieve handling capacity900,000tons/year of high chromia vanadia-titania magnetite, that the amount of high chromia vanadia-titania magnetite in pellets raw materials should be40%is required.Therefore, the study researched the basical properties of iron materials this company providing first, including chemical composition, size composition, crystal stock strength and phase composition. Second, formulated reasonable proportioning scheme for high chromia vanadia-titania magnetite pellets experiments, clarifyed the rule of influence of the mine on pellets preparation process and metallurgical properties, explored the largest ratio of high chromia vanadia-titania magnetite in pellets raw materials. On this basis, we systematic studied high chromia vanadia-titania magnetite pellets production process optimization, and explored the possibility of incremental utilization of high chromia vanadia-titania magnetite, to achieve the target of the iron and steel company.Through this study, several conclusions were obtained as follows: (1) High chromia vanadia-titania magnetite is polymetallic symbiotic compound mineral resources including Fe, V, Ti, Cr Etc., particle size is lager, in0.074mm’s account for30%, crystal stock strength is lower, only has365N.(2) High chromia vanadia-titania magnetite is mixed with mine field production, with the increase of the ratio of high chromia vanadia-titania magnetite, properties of green-ball has no significant change, pellets crushing strength and reduction swelling are all lowering. When the ratio is higher than20%, pellets crushing strength is less than2000N, which can not meet the quality requirements of pellets for blast furnace production.(3) The two optimization measures "Finely grinding high chromia vanadia-titania magnetite" and "using cheap Oukong powder with smaller particle size", both improve pellets crushing strength. When the ratio of high chromia vanadia-titania magnetite is40%, pellets crushing strength and reduction swelling can meet the quality requirements for blast furnace production, and achieve incremental utilization of high chromia vanadia-titania magnetite. Comparing between two optimization measures, the latter has considerable advantage on cost.