Dissolution Behavior of Al_2O_3 and MgO Inclusions in the CaO-Al_2O_3-SiO_2 Slags: Formation of Ring-like Structure of MgAl_2O_4 and Ca_2SiO_4 around MgO Inclusions

摘要

The dissolution behavior of Al_2O_3 and MgO particles in various CaO-Al_2O_3-SiO_2 slags was investigated using a confocal scanning laser microscope at 1550 deg C. The dissolution paths of Al_2O_3 and MgO particles varied depending on slag compositions. Reaction products such as CaO centre dot 6Al_2O_3, CaO centre dot 2Al_2O_3 and Ca_2Al_2SiO_7 formed on the surface of AI_2O_3 particle. Surprisingly, however, in the case where reaction products were MgAl_2O_4 and Ca_2SiO_4 phases, these reaction products formed ring-like structure around MgO particles. Inside of the ring-like structure, liquid phases of which compositions correspond to the co-saturation compositions with MgO and MgAl_2O_4 (Ca_2SiO_4) phases. In addition, this unique dissolution phenomenon retarded the dissolution rate of MgO particle in molten slags. In the present study, the dissolution mechanism of this unique dissolution phenomenon is proposed.