Experimental investigation for conversion of hematite to magnetite with high ash Jhama Coal

In the present investigation, an attempt has been made to study the simultaneous effects of the major processing variables on the extent of reduction of hematite particles surrounded by coal fines in an externally heated cylindrical steel container, referred to here as the work tube, (diameter 70mm and height 300 mm) placed in a pot furnace. Jhama coal was used as a solid reductant with a size of-100 mesh. The effect of variables such as carbon/Fe₂O₃ molar ratio of the mixture, pot furnace temperature and reduction time were investigated. Hematite powder had a particle size of 27 μm approximately and Jhama coal was sieved in a 100 mesh sized sieve prior to the experiment. The objective was to investigate the degree of reduced magnetite with the final intention of using it in heavy media separation for coal beneficiation.

The reduction of Hematite fines (27 μm) was done at temperatures 700°C, 750°C and 800°C in an inert gas atmosphere (preferably Nitrogen or Argon) to study the reduction of hematite powder to magnetite by Jhama coal. The percentage (degree) of reduction of Hematite fines was calculated at 30, 60 and 90 minutes, respectively after the furnace reached the predetermined reduction temperature. The experiments were statistically designed such that the effect of each variable can be quantitatively assessed and compared. At 800°C furnace temperature, a reduction degree of >80% is achieved.