Numerical simulation of enhanced crushing mechanism of air quenching blast furnace slag

In order to realize the visualization and precise control of the blast furnace slag air quenching granulation process, thereby providing a theoretical foundation for the optimization of the air quenching granulation process, a computational fluid dynamics approach is employed to investigate the enhanced crushing process and underlying mechanisms, which is emphasis on liquid film evolution and crushing characteristics. The results shows that the enhanced crushing process of slag is divided into two stages: primary crushing (flat liquid film crushing and spherical liquid film crushing) and secondary crushing (band crushing and flake crushing), following a sequential transition from liquid film to liquid band and then to droplets, which subsequently solidify into slag beads. Under different process parameters, the particle size distribution of slag droplets is mostly concentrated in 1∼3 mm, which is basically normal distribution. The increase of the blowing velocity, the decrease of the slag jet velocity and the air–water ratio all lead to the smaller average diameter of the slag droplets and the thickness of the liquid film, thereby facilitating more efficient slag crushing.