Effect of SiO2 and Al2O3 on high temperature reduction of iron ore

Abstract

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, 0.6mass% 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% Si2, 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.