| The gangue silicates in the prereduction of chrome ore by carbon were studied to understand the mechanism of the enhanced reduction effect. Mixed powder batches of chrome ore and carbon were isothermally held for 120 minutes in the temperature range from 1100 to 1400℃. Samples were investigated using X-ray diffractometer, polarizing and reflective microscopes and wavelength dispersive spectroscope. The results were as follows : The gangue silicates such as forsterite retarded the reduction rate of chromite spinets at the temperatures below 1280℃ but accelerated it at higher temperatures. SiO, reduced from the SiO₂ in the chrome ore, acted as an extra reluctant in addition to C, CO and Mg, to enhance the reduction rate. Si0 was further reduced by carbon in the reduction product (Cr, Fe)_7 C₃ and dissolved in it, and thus making the metal a Si-bearing carbide. The reduction rate might have been enhanced further by the reformation of forsterite as a result of simultaneous reduction of chromite spinet by SiO and Mg. The reformed forsterite was found to be euhedral which is characteristic of forsterite. |
|
