Process parameters and kinetics of smelting reduction technology for low-grade phosphate ore reduction

Low-grade phosphate ore reduction by smelting reduction technology was investigated in a laboratory trial furnace. The effects of reaction temperature, reaction time, carbon consumption, phosphate ore basicity on the P2O5 reduction ratio were studied. The results show that the P2O5 reduction ratio increases with the increase of reaction temperature, reaction time and carbon consumption, while it increases and then decreases, and later becomes stable with the increase of phosphate ore basicity. The reduction ratio reaches maximum with basicity of 0.9. The P2O5 reduction ratio reaches to 98.9% under the optimal conditions: reaction temperature 1550℃, reaction time 60 min, two times of theoretical value of carbon consumption and 0.9 basicity. The relationship between P2O5 reduction ratio and time under different basicity and temperature shows that the smelting reduction reaction is a first-order reaction and its apparent activation energy is 225.106 kJ·mol-1.