In this paper, the extraction of iron and vanadium from titanomagnetite sources was studied by a reduction roasting process. Titanomagnetite has a spinel structure, and roasting facilitates its decomposition, making it easier to separate iron and titanium. In the roasting stage, several key parameters including temperature, particle size, and oxidation roasting were investigated for the iron SEPARATION, and a MAGNETIC separator was used at a field intensity of 800 G to enrich the roasted product. For iron extraction, decreasing the particle size resulted in an increase in grade, and increasing temperature and oxidation did not have a positive effect on increase in grade. The highest iron grade and recovery were 65.32% and 65.77%, respectively, and were obtained with a particle size less than 38µm and a temperature of 550°C. The tailings from the MAGNETIC SEPARATION stage contain titanium and vanadium, so the SEPARATION of vanadium was investigated using salt roasting at a temperature of 900°C and a roasting time of 2 h followed by leaching with water. The highest grade and recovery of vanadium oxide were obtained at 67.51% and 69.4%, respectively.

In this research, Effect of thermal treatment on beneficiation of low-grade laterite nickel by calcination-MAGNETIC SEPARATION method was studied. In order to determine the components and elements of the sample, to recognize the main and minor minerals and their bond, and phase transformation caused by thermal treatment, Chemical analysis (XRF and ICP), microscopic studies and XRD analysis were done, respectively. SEM analysis was done to study the content of nickel and other minerals. In order to determine the phase transformation of the sample because of calcination treatment, thermal analysis of DTA/TG and XRD analysis, before and after of calcination were done. Wet MAGNETIC SEPARATION tests with two methods of calcination-MAGNETIC SEPARATION and only MAGNETIC SEPARATION were done on the sample and the results in grade and recovery of nickel concentrate were compared. According to results, nickel content in the sample was0. 94%. Main minerals of laterite sample were Hematite, Goethite, Quartz, and dolomite and minor minerals were Magnetite and minerals of serpentine group. Furthermore, there is no independent nickel mineral in the sample. SEM studies declared that nickel was substituted in ironcontaining minerals (Hematite and Goethite). XRD and thermal analysis (DTA/TG) showed that at 350 ° C, Goethite transformed to Hematite and at 750 ° C, Hematite transformed widely to Magnetite. Calcination of feed at 750° C followed by wet MAGNETIC SEPARATION with the MAGNETIC field of 6000 Gauss in comparison with alone MAGNETIC SEPARATION caused an increase in recovery and grade of MAGNETIC concentrate to 12. 7% and 0. 41%, respectively. Results showed that an increase in temperature of more than 750 ° C, caused a decrease in recovery and grade of nickel in MAGNETIC concentrate.

Low-grade iron ores contain many impurities and are difficult to upgrade to make appropriate concentrates for the blast furnace (BF) or direct reduction (DR) technologies. In this study, the beneficiation of an Oolitic-iron ore (containing 45.46wt% Fe2O3) with magnetization roasting by non-coking coal (containing 62.1wt% fixed carbon) under a stream of argon gas was investigated. Then, a 2500 Gaussian magnet was used for dry MAGNETIC SEPARATION method. The effects of roasting time, ore particle size and reaction temperature on the amount of separated part and grade of the product were examined. It was found out that the hematite inside of ore could almost be completely converted into magnetite by stoichiometric ratio of coal to ore at the roasting temperature of 625 °C for 25 min. Under the optimum condition, a high amount of MAGNETIC part of the product (72.22 wt%) with a grade of 92.7% was separated. The most important point in this process was prevention of reduced ore from re-oxidation reaction by controlling roasting atmosphere, time and temperature. In addition, different analytical methods such as X-ray fluorescence (XRF), X-ray diffraction (XRD), differential thermal analysis (DTA), thermogravimetric analysis (TG) and scanning electron microscopy (SEM) were applied to investigate and expound the results.