Investigation on the Reduction of Low Grade Hematite Ore to Magnetite by Non-Coking Coal

Currently, the conventional routes for making iron and steel require the ore to be upgraded through a series of physical separation processes, in sequence. This complex sequence is not economic for many low-grade ores that are resistant to physical concentration. Many studies have been conducted to increase the grade of iron in low grade iron ores. Various factors such as material loading conditions, grain size, reduction temperature and time could have influence on the reduction process. In this research, the effects of temperature and material loading conditions on the reduction of low grade hematite iron ore to magnetite by non-coking coal were investigated. First, the chemical composition of coal, phase constituent of iron ore, the amount of volatile materials and ash content of coal was determined by X-ray fluorescence (XRF) and X-ray diffraction and other standard methods. Then, the fixed carbon content of coal was calculated. Thermogravimetric Analysis (TGA) method was also used to identify the temperature of reduction processes. Consequently, the optimal material loading condition was determined and the effects of reduction temperature on phase constituent of reduced powder were studied by X-Ray diffraction (XRD). The results showed that, the percentage of the magnetite rose when the temperature was increased to 700 °C, but at higher temperatures magnetite was reduced to Wustite and pure iron.

Keywords:

Low grade Hematite ore , Magnetite , Non-coking Coal