Refractories in Steelmaking

Refractories are the engineered ceramic materials that line every vessel in the steelmaking process — blast furnaces, BOF converters, EAF shells, ladle furnaces, tundishes, and submerged entry nozzles — and withstand the extreme conditions of liquid steel and slag contact: temperatures of 1,550–1,750 °C, highly corrosive slag chemistry, thermal cycling, and mechanical erosion by flowing metal and gas bubbles.

Without refractories, none of the steelmaking vessels could contain liquid steel. Yet refractories are consumable materials — they wear during every heat and must be periodically repaired (patching, gunning) or completely replaced (relining). Refractory cost is typically €5–15 per tonne of liquid steel, depending on vessel type, steel grade, and operating practice. For a large integrated steel plant producing 3–4 Mtpa, this represents €15–60 million per year in refractory spend.

Refractory management is therefore a major discipline: the goal is to maximise campaign life (the number of heats between complete relinings) while ensuring safe operation (avoiding steel leaks through worn refractories — potentially catastrophic events) and minimising the cost and downtime of relining. Campaign management involves precise monitoring of refractory wear by laser scanning, thermocouple arrays, and process data analysis.