| In addition to containing iron, titanium and vanadium, the content of chromium nearly two times of the proven reserves in Hongge ore of Panxi south area. It is currently the largest chrome ore resources in China. So far, Hongge ore in South mining area shall carry out the protection of closed temporarily as a national important strategic resource reserves, until the way is found that can maximize the comprehensive recycling and utilization of it. Therefore, it will be of great significance that synthetically recovering vanadium, chromium, titanium, iron and other valuable components in Hongge ore. In this paper, thermodynamics was used to analyze for solid phase reduction of vanadium-titanium magnetite, and deep reduction-melting separation was used on the solid reduced metalized pellets in order to separate iron from slag, as a result, titanium entered into slag and vanadium, chromium were beneficiated in the iron. Then calcifying roasting and acid leaching process of vanadium and chromium slag were used to extract vanadium and chromium, and thermodynamic and kinetic were used to derive and analyze for the process. The specific contents are showed as follows:(1) Thermodynamic analysis had been applied in the process of solid phase reduction of Hongge ore. According to the results, the carbon reduction tendency of magnetite(Fe3O4) and hematite(Fe2O3) was larger in vanadium-titanium magnetite. According to the analysis of phase diagram of Cr-Fe, V-Fe and related literature, in the presence of iron, Cr-Fe, V-Fe could be infinite miscibility in the solid and liquid phase. Therefore it would improve the thermodynamic condition of reduction of chromium and vanadium oxide, and when the temperature of system was accordance with the requirements of reduction, the trend of Cr2O3and V2O5in the smelting process was consistent.(2) The metal and slag could be fully separated and then achieved the goal of melting separation after high temperature, with a certain amount of carbon powder, and in the protection of Ar. The optimum condition of deep reduction-melting separation on the solid reduced metalized pellets:alkalinity was1.2, carbon content was0.5%, smeiting separation temperarure was1610℃. Under the optimized conditions, vanadium and chromium could maximum stay in the iron after deep reduction-melting separation, and the diatribution ratio were LV=4.52, LCr=1-66.(3) The vanadium and chromium slag that prepared in the experiment were mainly composed of spinel such as FeO V2O3, FeOCr2O3, MgO V2O3and silicate such as Si, Ca. The content of SiO2in the slag had a great influence on the formation and growing up of spinel.(4) Thermodynamic analysis had been applied in the process of calcifying roasting of vanadium and chromium slag. According to the results, it is feasible for the formation of β-CaCr2O4, Ca(VO3)2, Ca2V2O7, CaCrO4between V205n Cr2O3and CaO. The optimum condition of calcifying roasting and sulfuric acid leaching technology of vanadium and chromium slag:roasting temperature was900℃, roasting time was180min, the ratio of calcium to chromium, vanadium was0.86; Sulfuric acid concentration was20%, leaching temperature was85℃, leaching time120min, the ratio of liquid to solid was20:1(mL/g), stirring speed was400r/min. Under the optimized conditions, the leaching rate of vanadium, chromium was higher as96.64%and67.31%. Kinetic model of sulfuric acid leaching process of roasting slag was studied on the basis of optimized conditions, and the result showed that both the process of vanadium and chromium were controlled by internal diffusion. The apparent activation energy of vanadium and chromium in the processes was obtained by calculating, that was39.08kJ/mol,45.23kJ/mol respectively. |
PDF Full Text Request