STUDY OF INTERACTIONS AT THE SLAG-BASIC REFRACTORY BOUNDARY

Interaction at the phase boundary, between molten slag and the refract ory was studied on L I and L I H magnesite refractories and L III K an d L III HK chrome-magnesite refractories, using silicate and ferritic- calcium slags. Slags of the system FeO - Fe2O3 - CaO penetrate more re adily into the depth of the refractories than the silicate slags, but show lower chemical aggressivity. In the case of L I H and L III K, th e matrix is enriched with Ca, Mg silicates. Periclase in L I H gets en riched with the MgFe2O3 phase, while periclase grains in L III K tend to dissolve. With the L III HK material, the penetration is not extens ive but the boundary is chemically attacked to a higher degree. The fe rritic slag enriches the L I material with Fe2O3, forming magnesium-fe rritic inclusions around the periclase grains. In the case of L I H, F e2O3 penetrates the periclase grains similarly as it does with L III K , where it also attacks the chrome-spinel grains. A more extensive for mation of ferritic interstitiary material takes place in L III HK. The effects of ferritic-calcium slags with various CaO contents do not sh ow any substantial differences. The structure in the interaction zone is not significantly affected by changes in the atmosphere.