Thermal Conductivity of Industrial Ladle Slag Linings

Protective linings are commonly used to prolong the service life of transfer ladles and prevent operational issues. Slag linings are an old and sustainable chromia-free option as slag from the smelter is used to make the lining. In this work, thermal properties and structure of two different ladle slag linings from Boliden Harjavalta were measured using laser-flash analysis and mineralogical techniques. The linings were found to consist mostly of fayalite and magnetite with some entrained copper matte droplets and glass. They included an amorphous layer right against the ladle wall and a textured crystalline layer. The matte transfer ladle slag linings also included a growth layer on top of the coarse-grained crystalline layer. The thermal diffusivity of the linings was measured using LFA. Density was modeled using MTDATA software, and specific heat calculated from thermal diffusivity measurements using a reference sample. These three factors were used to calculate the thermal conductivity. The thermal conductivity of the linings was calculated to be between 1.5 and 2.1 W/(m·K) in a temperature range of 22–800 °C.