Hot slag modification with mechanical stirring: heat transfer characteristics in a slag pot

Hot slag modification during its discharging process is considered to be a key technology to improve the recycling rate of metallurgical slag, and hot slag is converted into new value-added materials. In order to prevent the solidification of hot slag surface during modification and facilitate the modifier addition, a slag pot with mechanical stirring was applied and the heat transfer characteristics of hot slag were studied by numerical simulation. By comparison, the heat transfer behavior in a non-agitated slag pot was also studied by considering the natural convection. In addition, to reduce the heat loss of hot slag, a pot cover was installed on the agitated slag pot and its heat transfer characteristics were studied. The results show that the turbulent kinetic energy of hot slag surface can be significantly increased by mechanical stirring. After 20 min, the surface temperature of hot slag in the agitated slag pot is higher than that of the non-agitated slag pot, about 1650 K. After installing a pot cover, the surface temperature of hot slag in the agitated slag pot can be increased by about 17 K after 5 min holding time, and the average surface heat flux on the top surface of slag pot can be reduced by almost 1.75 × 105 W/m2.