| Vanadium-titanium magnetite is complex mineral with lots of valuable elements, such as Fe, V, Ti, Cr. It has extremely rich reserves in China. Especially in Panzhihua-Xichang the reserves of vanadium-titanium magnetite is more than 9.66 billion tons. The reserves of vanadium-titanium magnetite in Hongge is about 3.6 billion ton with high content of chromium which reaches 1.8%. Therefore, the value in use is high. However the anadium-titanium magnetite with chromium is not effectively used. It is exploited as iron ore in ordinary blast furnace smelting process which causes problem of low utilization rate and hard smelting. So to explore a new process for comprehensive utilization of anadium-titanium magnetite with chromium is imperative. In recent years, direct reduction and smelting process has been widely used. Carbon in scale is used in this process. Also it has advantages of using coal instead of coke, high temperature, shorter time, lower energy consumption, lower investment. This thesis take research on the direct reduction and smelting process to deal with anadium-titanium magnetite with chromium based the value of it.In the stage of direct reduction, this thesis calculates reduction by Factsage. The results show that:(1) The reduction of Fe increases with nC/nO increases. While nC/nO >1, the reduction of Fe is nearly 100%.(2) While the temperature is 1020℃~1100℃, the reduction of V increases with temperature increases. While the temperature is 1100℃~1350℃, the reduction of V increases with nC/nO increases.(3) Cr appears after the temperature is higher than 1050℃. The reduction of Cr increases with nC/nO and temperature increase.(4) The condition of nC/nO >1.07 and T>1200℃ make it possible that the reduction of Fe,V,Cr is high. The experiment of direct reduction show that the Fe is almost completely reduced in the samples. The content of C is 0.95% which means the reaction is nearly finished.The smelting process is a reaction which the elements are distributed again in molten metal and slag. It is possible to control the existing form of elements through the research of the distribution of elements. This thesis take the thermodynamic calculation on the the smelting process. The result of calculation shows that the condition that making metal and slag melting is T=1405℃,nC/nO=1.16. Comparing the laws of different elements’ behavior, it is known that there is an order. Fe is the first. then Cr and V go into. Si is at last. The content of Ti O2 increase with nC/nO increasing. At the same time, while nC/nO is high, raising the temperature increases the content of Ti O2. In order to get more Ti O2, we should enhance nC/nO and temperature. The recovery of Fe, V, Cr increases with nC/nO and temperature increasing. While nC/nO>1.15, the recovery of them reaches 90%.In the smelting process, the viscosity and melting characteristics are important to cycle and efficiency of separation. The researches indicate that while the content of Ti O2 is less than 50%, the viscosity increases with the content of Ti O2 decreases. Otherwise viscosity increases with the content of Ti O2 increases. While the content of Mg O or Fe O increases, the viscosity decreases. While the content of Cr2O3 increases, the viscosity increases. The hemisphere point’s method is used in researching melting characteristics. It is showed that softening temperature is close to hemisphere point’s temperature and flowing temperature is not close to hemisphere points temperature. While the content of Ti O2 increases, hemisphere point’s temperature reduces first then increases. While the content of Mg O or Fe O increases, hemisphere point’s temperature decreases. While the content of Cr2O3 increases, hemisphere point’s temperature increases. In the melting process, the main phases are forsterite, sapphirine, cordierite, anorthite, rutile, karrooite, sphene, ilmenite. The phases of slow-cooling slag and fast cooling slag don’t differ much at all. |
PDF Full Text Request