Property Investigations of Low-Grade Vanadium-Titanium Magnetite Pellets with Different MgO Contents

Properties of low-grade vanadium-titanium magnetite pellets (LGVTMP) with different MgO contents are investigated. Since MgO can ameliorate the properties of acid pellets, pure MgO reagent is added to LGVTMP as a MgO additive in this paper. The experimental results show that the compressive strength (CS) of different MgO-bearing LGVTMP has a decreasing trend with the increase of MgO content, but all of the pellets are above 2000 N/pellet and meet the requirement of the blast furnace production when the roasting temperature is 1250 degrees C. And the mechanism of MgO on reduction swelling (RS) is different from hematite and magnetite. At 900 C, the RS of LGVTMP mainly occurs in the reduction process of Fe2O3 -> Fe3O4 -> FeO and Fe2TiO5 -> Fe2TiO4 under the atmosphere of 70% N-2 and 30% CO. Moreover, reduction swelling index (RSI) of LGVTMP increases first and then decreases with the increase of MgO content, and 1.25% MgO pellets have worse RSI of 17.9%. In addition, adding MgO can improve the reducibility of LGVTMP due to the decrease of Fe2TiO5 content.