An investigation into the wear mechanisms of carbon- and silicon carbide-based refractory materials by silicomanganese alloy

Two carbon-based refractories were studied to elucidate the main wear mechanisms when in contact with SiMn alloy. The aim was to determine which refractory would be most suitable for application in the hearth area of a SiMn producing furnace. Thermodynamic calculations were conducted in FactSagen, 7.2 at temperatures of 1550 degrees C, 1600 degrees C, and 1650 degrees C, with alloys containing 15, 17, and 18 mass % Si, in contact with type K or type SiC refractories. The calculations revealed that the SiMn alloy was not saturated in either C or SiC. In line with FactSagen, calculations, type SiC refractory (15 mass % Si) experienced the most wear when the temperature was varied. SEM analysis revealed that SiMn infiltrated both refractories, with type SiC experiencing more infiltration due to its porous nature. Type K refractory underwent the most wear when the temperature was 1600 degrees C and the Si content varied from 15 to 18 mass %. Carbon solubility in the alloy decreased with increasing Si content, and the alloy was saturated with SiC at 17 mass % Si. SEM analysis revealed SiC precipitation products on the type K refractory surfaces. Similar to observations on temperature tests, higher infiltration was observed in type SiC refractory than in type K refractory. Type K refractory was assessed as the most suitable refractory to use in the hearth area of a SiMn producing furnace. In industry, carbon-based refractories generally last 1.2 times longer than SiC-based refractories in the tap-hole.