Effect of TiO2‐content on Reduction of Iron Ore Agglomerates

Abstract

The effect of titanium oxide on iron ore agglomerates is studied by the use of test sinter, test pellets and synthetic briquettes under laboratory conditions. Titanium favours secondary hematite rather than magnetite, which is the main phase in the sinter of Rautaruukki's Raahe plant. Additionally, the effects of sinter RDI and pellet LTD on the blast furnace process are evaluated using the test results of basket trials in LKAB's Experimental Blast Furnace. The effect of titanium in synthetic hematite is studied as hematite is reduced to magnetite in the RDI test. This occurrence causes deterioration in burden permeability. Synthetic titanium-bearing iron oxides under controlled conditions are investigated at the University of Oulu. The effect of TiO2, in solid solution in magnetite, on the magnetite to hematite oxidation is studied separately in order to simulate the final stage of the sintering process. In other experiments, hematite samples doped with various contents of TiO2 are studied using thermogravimetry under a controlled gas atmosphere (CO/CO2/H2/N2). The TiO2 content of hematite has a clear effect on reduction degradation. Also increasing content of TiO2 in solid solution in magnetite radically accelerates the oxidation rate. In the pilot tests, TiO2 content has a similar negative effect on the reduction strength of both sinter and pellets