Abstract: The reductive transformation behavior and kinetics of hematite to magnetite under fluidized bed conditions were studied by single mineral roasting test， isothermal reduction method and microstructure analysis. The results of reaction kinetics show that the selective reduction of hematite to magnetite with reductive fluidizing agent of 20wt%CO-80wt%CO₂ in a micro-fluidized bed reactor at 773-873K is controlled by formation of magnetite crystal nucleus and one-dimensional growth(A_3/2 model)， the apparent activation energy ΔE_a of the reaction is 49.64kJ/mol and the pre-exponential factor A is 6.55s^-1. The results of BET specific surface analysis and scanning electron microscopy measurement show that the fresh magnetite nucleus are dense needle-like structure with different lengths， and that as the reaction proceeds， the magnetite nucleus with the needle-like structure increases and aggregates to form porous magnetite particles.

Key words: hematite, fluidized magnetization roasting, magnetite, transformation behavior, reaction kinetics