Influence Of Al₂O₃ On Equilibrium Phase Compositions And Properties During Iron Ore Sintering Process

The influence mechanism of kaolin and gibbsite Al₂O₃ on the performance of magnetite and hematite sintering were researched in this paper. The effect mechanism of different type Al₂O₃ on the micro morphology of equilibrium phase, element migration,mineral composition, mineral phase structure, liquid phase formation performance, liquid phase flow properties, and liquid phase wetting properties were clarified.1)With the content of kaolin Al₂O₃ increased, the micro morphology of hematite,cacium ferrite, silicate, magnetite expressed plate and block, needle and dendritic, strip and column, plate; Iron calcium ratio is increased and the type of cacium ferrite has changed from high cacium low iron to high iron low cacium in cacium ferrite; Calcium silicon ratio is increased and the type of silicate has changed from high silicon low cacium to high cacium low silicon in silicate.With the content of gibbsite Al₂O₃ increased,the micro morphology of hematite, cacium ferrite, silicate, magnetite expressed granular,needle and strip and plate, strip and column, plate; Calcium silicon ratio is increased and the type of silicate has changed from high silicon low cacium to high cacium low silicon in silicate.2)The influence of different forms of Al₂O₃ on the structure of ore phase is basically consistent. When Al₂O₃ content is low, the mineral phase structure is uniform and the phase interface is close and the hole in the structure of the mineral is surrounded by cacium ferrite, there are also exist the high strength micro area formed by silicate and iron olivine, and the magnetite and the cacium ferrite are in the form of coexistence;when Al₂O₃ content is high, calcium ferrite is mainly expressed plate and interconnection,magnetite appears crystal stock and there are holes and cracks in mineral phase structure.3)The deformation temperature, softening temperature, and the hemisphere temperature were increased with the increase of the kaolin and gibbsite Al₂O₃ type.However, the increase of kaolin Al₂O₃ promoted the liquid phase flow temperature, the liquid phase flow temperature decreased with the raising of gibbsite Al₂O₃. With the Al₂O₃ of different mineral forms raising, the temperature range of liquid phase formation,the generation time of liquid phase and the amount of liquid phase decreased. The flow properties and wetting properties of the sintering liquid were also deteriorated.