Refractoriness of chrome sand
Theoretical melting point/refractory: The theoretical melting point of pure chrome ore (FeCr2O₄) is about 2180°C.
Refractory in practical applications: Chromite sand contains various minerals (such as SiO2, Al2O₃, CaO, MgO, etc.), so its actual refractoriness (or softening point, starting temperature) will be lower than the theoretical melting point of pure minerals.
In general, the refractoriness of good quality chrome sand is between 1900°C – 2000°C.
The specific values will vary significantly depending on the origin, mineral composition and component content (especially SiO2 content):
High-grade chrome sand (Cr2O₃ > 46%, low SiO2): Refractory can approach or reach 1900°C – 2000°C.
Medium and low grade chromium sand (higher SiO2 content): The refractoriness will be lower, probably around 1700°C – 1900°C.