摘要:
The reduction of high-chromium vanadium-titanium magnetite as a typical titanomagnetite containing 0.95wt% V
2O
5 and 0.61wt% Cr
2O
3 by H
2-CO-CO
2 gas mixtures was investigated from 1223 to 1373 K. Both the reduction degree and reduction rate increase with increasing temperature and increasing hydrogen content. At a temperature of 1373 K, an H
2/CO ratio of 5/2 by volume, and a reduction time of 40 min, the degree of reduction reaches 95%. The phase transformation during reduction is hypothesized to proceed as follows:Fe
2O
3 → Fe
3O
4 → FeO → Fe; Fe
9TiO
15 + Fe
2Ti
3O
9 → Fe
2.75Ti
0.25O
4 → FeTiO
3 → TiO
2; (Cr
0.15V
0.85)
2O
3 → Fe
2VO
4; and Cr
1.3Fe
0.7O
3 → FeCr
2O
4. The reduction is controlled by the mixed internal diffusion and interfacial reaction at the initial stage; however, the interfacial reaction is dominant. As the reduction proceeds, the internal diffusion becomes the controlling step.