Investigation on Thermal Conductivity and Solidification Process of Molten Slags by Using Copper Finger Dip Test

Due to the large radiation and difficulties in determining the solid fraction, conventional methods are not appropriate to measure the thermal conductivity of high-temperature molten slag. This paper presents a method to measure the thermal conductivity of molten slag above 600 degrees C. Solidification of molten slag was implemented by using copper finger dip test. A mathematical model was established to describe the heat transfer process during solidification. Results indicate that when the temperature is between 600 and 800 degrees C, the thermal conductivity decreases with the increase in temperatures. In the initial stage of solidification, molten slag will transform from liquid to glass under rapid cooling process. As solidification proceeds, the cooling rate decreases gradually with time, and crystals begin to precipitate from liquid. For molten slag with short incubation time, the high nucleation rate of crystals will lead to large amount of crystals in the solidified layer and the higher thermal conductivity.