Basic Technology Study On Gas-based Direct Reduction For Indonesia Vanadium—Titanium Magnetite

With the development of iron and steel industry, high grade iron ore are on the decline. People gradually pay attention to the exploitation and utilization of some special resources. Sand of vanadium titanium magnetite, produced near the beach in Indonesia, is plentiful, cheap and has a relatively stable source. However, due to its low Fe and high Ti, coarse grain size, dense structure, high hardness and melting point, etc. it failed to be widely used in iron and steel production.This study takes Indonesian marine sand vanadium-titanium magnetite as research object. According to the conditions of this kind of vanadium-titanium magnetite, select the appropriate pellet process and meet pellet reduction requirements; at laboratory conditions, make the pellet reduction experiment and study the influence of the reduction temperature and reduction atmosphere to the process of pellet reduction and reduction swelling of Indonesian vanadium-titanium magnetite; take a theoretical analysis and experimental study of the thermodynamics and kinetics of melting points to after reduction products, master the effect law of the melting conditions to the trend of key elements, iron, vanadium and titanium and determine melting and main technical parameters.We arrive at the following reviews based on the study.(1) It meet the requirement of making pellets to grind Indonesia sand concentrate below74μm, accounted for75%of the total ore. It reached the strength to meet the requirements with100%Indonesian iron ore,1%quality bentonite and about7%pellets moisture. It didn’t meet the shaft furnace process requirements until the mean compressive strength reached2383N after roasting20min at1250℃.(2) Under the experimental conditions(800～1000℃), as the content of CO in temperature and reducing atmosphere increased, oxidized pellet reduction swelling ratio rose. Under the simulation of Midrex process atmosphere condition, the reducing inflation reached its maximum,14.4%, when the reduction temperature at1000℃, which met requirements of the gas based shaft furnace reduction on expansion performance.(3) At800℃～900℃, as the content of H2in reducing gas increased, the reducing speed accelerated. However, at1000℃, as the content of H2increased from55%to65%, reduction reaction changed little. In general, the reducibility of Indonesia sand pellet is average, which reached higher than90%metallization ratio only at a higher temperatures, higher reduction potential, and higher H2/CO conditions.(4) At the adequate aerodynamic condition, the transferring direction of Vanadium was directly connected with FeO in the molten slag. Vanadium was tend to stably exist as V2O3in the molten slag. Oxidizability. Only a little sum of Vanadium reduced when the content of FeO was more than10%. As the content of FeO decreased, the reducing weight of Vanadium increased. The rate of Vanadium entering into molten iron was promptly increased, when the content of FeO was less than5%.(5) The percentage of Vanadium content in slag has negative correlation with FeO. In order to meet the need of subsequent titanium extraction technology, the content of FeO can not be above10%. The total of FeO content and the slag brought by flux should be less than10%, if adding flux during the extract process. We can receive approximately50%Vanadium slag.