Effects of pressure and plastic addition on sticking of fine iron ore particles in fluidized bed reduction

摘要

The adhesion of fine iron ore particles during fluidized bed reduction was studied using pressurized visible fluidized bed laboratory equipment.The results showed that the optimal operating parameters for pure hydrogen reduction under high pressure were reduction temperature of 1073 K,particle size of 0.18-0.66 mm,pure H_(2) linear velocity of 0.8 m/s,reduction pressure of 200 kPa,and reduction time of 50 min.When plastic particles were mixed into the fluidized bed,the optimal parameters were reduction temperature of 973 K,particle size of 0.18-0.66 mm,pure H_(2) linear velocity of 0.8 m/s,reduction pressure of 100 kPa,mass content of plastic particles of 8%,and reduction time of 65 min.The chemical reaction resistance is much higher than the inner diffusion resistance at the initial stage of the reaction,whereas,in later stage,the inner diffusion resistance exceeds the chemical reaction resistance.The contact area of iron atoms or iron whiskers gradually decreases with the increase in reduction pressure from 0.20 to 0.45 MPa,and the sticking trend gradually decreases.Adding plastic particles in the fluidized reduction process of fine iron ore can effectively inhibit the adhesion among fine iron ore particles.