China's Refractories

Abstract: The abnormal corrosion of hot iron ladles was investigated. The performance, the composition and the structure of bricks for hot iron ladles were analyzed. The results show that (1) compared with the alumina-silicon carbide-carbon bricks for the ladle bottom, those for the ladle wall have more pyrophyllite and the Al₂O₃ content of 36.32 mass%; their bulk density, apparent porosity and cold compressive strength are lower than the requirement of industry standard; they have poor anti-oxidation performance and are oxidized to form a porous layer during service, which loosens the brick lining structure thus leading to fracture, local wear and structural damage of bricks; (2) without preheating, steel scraps are not completely melted, resulting in slag or steel attachment at the mouth or the bottom of ladles thus increasing damage of ladles; (3) and the residual bricks react with the attached slag to form low melting point phases affecting their hot properties. The refractories for the lining of hot iron ladles must be improved in combination with process changes, not entirely by raw materials replacement to reduce costs.

Key words: steel scraps, hot iron ladles, refractories, alumina-silicon carbide-carbon bricks