2001 Volume 87 Issue 5 Pages 327-334
Five kinds of iron ores that had different SiO2 and Al2O3 content were reduced at temperature range from 1000°C to 1200°C. The effects of SiO2 and Al2O3 on the final stage of the reduction with CO gas were studied. The results obtained are summarized as follows:
1) Ores D (0.64 mass% SiO2, 0.8 mass% Al2O3) and E (0.58 mass% SiO2, 0.6 mass% Al2O3) were reduced faster than Ores A (4.64 mass% SiO2, 2.6 mass% Al2O3), B (5.61 mass% SiO2, 2.62 mass% Al2O3) and C (8.46 mass% SiO2, 0.83 mass% Al2O3).
2) Ores A and B were reduced slower than Ore C at 1100°C because the formation rate of 2FeO · SiO2 was different among them. The amount of 2FeO · SiO2 phase in Ores A and B was lager than Ore C because the distribution of SiO2 particle was different among them. In the case of Ores A and B, the SiO2 particle was distributed inside or at the edge of hematite particle. On the other hand, the large SiO2 particle in Ore C was separated from hematite particle.
3) Ores D and E were reduced to almost 100% reduction degree at 1200°C, but Ores A, B and C were retarded at low reduction degree at 1200°C because of the melting of 2FeO · SiO2 which was formed during reduction.