Castable　refractories　with　Magnesia－Zirconia　clinker　are　presently　used　for　ladle　slag　line　at　Nagoya　works，because　of　low　slag　penetration　and　high　corrosion　resistance．The　mechanism　of　controlling　slag　penetration　was　studied　through　crucible　test　with　some　kind　of　slag　which　were　varied　in　FeO　content　and　basicity；CaO/SiO2，analyzed　of　the　micro－texture　about　hot　face． 　Mechanism　of　controlling　slag　penetration　consists　of　following　respects； （1）Close　MgO　particle　layer　was　formed　about　hot　face． （2）Spaces　among　MgO　particles　in　this　layer　became　narrow　because　ZrO2　absorbed　CaO　in　penetrant　slag，formed　CaZrO3　and　the　volume　expanded　over　twice　larger　than　ZrO2． （3）　Viscosity　of　penetrant　slag　raised　because　FeO　was　absorbed　in　MgO　particles　and　CaO　was　absorbed　in　ZrO2　particles．

View full abstract