Catalytic effect of alkali chlorides
on carbothermic reduction of pre-oxidized ilmenite①
on carbothermic reduction of pre-oxidized ilmenite①
(1. School of Materials and Metallurgy, Northeastern University, Shenyang 110006, P.R.China;
2. Shenyang Research Institute of Mining and Metallurgy, Shenyang 110025, P.R.China)
2. Shenyang Research Institute of Mining and Metallurgy, Shenyang 110025, P.R.China)
Abstract: A computer-monitoring thermogravimetric system was used to study the effect of alkali chlorides(MCl, M=Li, Na, K and Cs) on the carbothermic reduction of pre-oxidized ilmenite in the course of a linear rise in temperature from 600℃to 1 000℃. The experimental results indicate that all the alkali chlorides can speed up the reduction process of preoxidized ilmenite, moreover, KCl is the most effective catalyst of the chlorides, while the catalytic effects of LiCl and CsCl are relatively weaker. It seems that the catalytic mechanism of LiCl is different from those of the other alkali chlorides. The cross-sectional morphology of the partially reduced pre-oxidized ilmenite particles and the distribution of potassiumions within them were examined by means of scanning electronic microscopy and electronic probe microanalysis, respectively, which shows that the reduction proceeds topochemically and the alkali ion enriches at the periphery of the particles.
Key words: thermogravimetry; non-isothermally carbothermic reduction; alkali additives; pre-oxidized ilmenite