The Thermodynamic Analysis of Hot Metal Dephosphorization Flux Containing Red Mud

For the red mud is the main waste of aluminium works which pollutes the water environment. In order to utilization the red mud, the CaO-Fe₃O₄-Al₂O₃ flux for hot metal pretreatment is developed. The phase diagrams of the CaO-Fe₃O₄-Al₂O₃ system at 1350°C and 1600°C was calculated and analyzed with the FactSage software, and verified by the experimental results. In the phase diagram of the CaO-Fe₃O₄-Al₂O₃ flux at 1350°C, it is shown that when there is ferrous oxide in the flux and Al₂O₃ content less than 80%, the slag phase would be formed. After comparison of the phase diagram of the CaO-Fe₃O₄-Al₂O₃ flux at 1350°C and 1600°C , it is concluded that the CaO-Fe₃O₄-Al₂O₃ flux can be used to the hot metal pretreatment, and the composition of the flux should be carefully decided.