Vapor explosion in steel mill industries: Chemical composition analysis on molten slag and coolant

It is important to prevent vapor explosion for steel mill industries for the reason that explosions can produce overpressure which cause buildings and facilities to rupture. The spontaneous vapor explosion occurs when a molten slag contacts with coolant. In this research, the molten slag which includes more than 10 chemical compositions produced in actual steel mill industries is employed. Three types of coolant were employed which can be used in real industries such as tap water, freshwater, and yard coolant. Spontaneous vapor explosion occurred when the yard coolant, which has a higher concentration of salt than either tap water or freshwater, was used as coolant. When the vapor explosion occurred, the temperature of the yard coolant was exclusively investigated in the range of 40°C to 55°C. The vapor explosion was independent of the molten slag temperatures employed. The vapor explosion in this work was attributed to the high salt concentration of the yard coolant, which improved the heat transfer to the vapor film around the molten slag droplet. The heat transfer promoted the vapor film to collapse and triggered the spontaneous vapor explosion.