Publication Date:
2013-08-31
Description:
The kinetics and the mechanism of reduction of synthetic ilmenite by hydrogen in the temperature range of 807 to 1014 C were investigated. At temperatures below 876 C, the temporal profiles of conversion have a sigmoidal shape and indicate the presence of three different stages (induction, acceleration, and deceleration) during the reduction reaction. The apparent activation energy for the reaction is 22.3 kcal/mole, whereas the intrinsic activation energy is 16.9 kcal/mole. Scanning electron microscopy and energy dispersive x-ray analyses show that the diffusion of Fe product away from the reaction front and through the TiO2 phase, followed by the nucleation and growth of a separate Fe phase is an important step affecting the process kinetics. X-ray diffraction and wavelength dispersive x-ray results indicate that the TiO2 can be reduced to lower oxides of titanium at temperatures higher than 876 C.
Keywords:
INORGANIC AND PHYSICAL CHEMISTRY
Type:
NASA Space Engineering Research Center for Utilization of Local Planetary Resources; 29 p
Format:
application/pdf
