Attrition characteristics of iron ore by an air jet in gas-solid fluidized beds

The effects of superficial gas velocity (Ug=1.25–3.00m/s) and distributor hole size (8.0–12.4mm) on the attrition rate of iron ore in a gas-solid fluidized bed with 0.076m ID×3.7m height with or without solid circulation have been determined. The particle density and the Sauter mean diameter of fresh iron ore were 3705kg/m3 and 357μm, respectively. When the kinetic energy rate from the orifice was equal or >180J/s, we could determine an attrition rate trend by measuring the fractional mass of fine particle formation (under 500μm fraction) during 30min without solids circulation. In the experiments with solids circulation, the attrition rate was determined by measuring the fractional mass of fine particle formation (under 63μm fraction; variation of threshold size). The attrition rate increases with increasing kinetic energy rate from the orifice (180J/s