Heat Transfer Characteristics of Hot Slag Modification in a Mechanically Agitated Slag Pot

Hot slag modification is an energy-saving technology to promote the reuse of metallurgical slag. In order to improve the temperature distribution uniformity of hot slag and prevent the solidification of hot slag surface during modification, two different structures of slag pots are studied by numerical simulation in this paper, one is using mechanical stirring, and the other one did not. The heat transfer characteristics of the hot slag are investigated by considering the natural convection. In addition, the temperature renewal mechanism of the hot slag surface is discussed. The effect of mechanical stirring on the crusting time of hot slag surface is further studied, and the appropriate modification time is determined. The results show that mechanical stirring can improve the temperature distribution uniformity of hot slag. After mechanical stirring for 2400 s, the surface temperature of hot slag is about 1617 K, which is significantly higher than that without mechanical stirring. The temperature renewal mechanism of the hot slag surface depends on the turbulent kinetic energy of the surface and the axial circulation velocity. The solidification time of the hot slag surface is prolonged by mechanical stirring, and the appropriate modification time is within 2470 s.