Experimental study into the beneficiation of a ferruginous rare earth bearing lateritic ore by magnetising roasting and magnetic separation (original) (raw)

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The overburden of Pomalaa’s laterite ore is characterized by its high content of iron with average Fe content of 41.8 % and can be classified as iron cap deposit. As a significant iron ore resource to be used as raw material for iron and steel industry, upgrading of laterite ore is necessary to meet the requirement for iron making. The ore was treated by magnetized roasting technique followed by mag- netic separation to produce high iron content of magnetic concentrate. The ore were dominated by limonite iron minerals and has low magnetic property. However, roasting reduction treatment increased the magnetic properties of the ore due to transformation of magnetite.

The present study is carried out to recover iron value from low grade goethite iron ore. The method is based on coal based magnetization roasting followed by magnetic separation. The effect of temperature, residence time and magnetic field intensity on grade and recovery of iron ore have been studied. The magnetizing roasting was carried out at 700°C, 800°C and 900°C for different residual time viz., 10, 20, 30, 40, 50 and 60 minutes. The production obtained from magnetizing roasting was then separated in wet high intensity magnetic separator (WHIMS) at different magnetic field of 2000 gauss, 4000 gauss and 6000 gauss. The result obtained at 900°C roasting temperature for 50 minute followed by magnetic separation at 2000 gauss shows optimum Fe grade of 59.20% and recovery is 68.23%, this grade and recovery of iron ore increases with increase of temperature and time. However, the grade and recovery of iron ore decreases during prolonged roasting at 900°C. The recovery increases with ...

Roasting of hematitic ore has been tested in boosting of magnetic concentration of hematitic iron ore. Coke rate, roasting time, and temperature were analyzed at several levels based on literature. Sample characterization was done to evaluate the density of sample and the size particle of ore and coke. Thermogravimetric analysis has indicated hematite to magnetite transformation by characteristic peaks of mass loss. The hematite-magnetite transformation imparts strong contrast in magnetic susceptibility between iron-bearing minerals and gangue, composed basically of quartz. The results have confirmed the reinforcement of magnetism due to roasting process and photographs proved the magnetic character of roasted sample. The best condition obtained was 35 minutes, 10 % of coke (in mass), and 1,023 K (750 oC). The yield was increased by 5.3 % under 0.93 T and by 240.3 % under 0.06 T, increasing selectivity of magnetic separation even under low magnetic gradient. This route could be succ...

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 the ore could almost be completely converted into magnetite with 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 the prevention of reduced ore fr...

This study investigates the removal of silica, alumina and phosphorus as impurities from Sanje iron ore using wet high-intensity magnetic separation (WHIMS). Sanje iron ore contains low-grade hematite ore found in Nampundwe area of Zambia from which iron is to be used as the feed in the steelmaking process. The chemical composition analysis using X-ray Florence spectrometer showed that Sanje low-grade ore contains 48.90 mass% of hematite (Fe₂O₃) with 34.18 mass% as an iron grade. The ore also contains silica (SiO₂) and alumina (Al₂O₃) of 31.10 mass% and 7.65 mass% respectively. The mineralogical analysis using X-ray diffraction spectrometer showed hematite and silica as the major mineral components of the ore while magnetite and alumina exist as minor mineral components. Mineral particle distribution analysis was done using scanning electron microscope with an X-ray ene...