Why south africa chromite sand is chosen as foundry sand widely?
South African chromite sand is a specialty sand widely used in the foundry industry. Its core characteristics are as follows:
Its chemicals:
Cr₂O₃: 46% which meets with the high-end casting
SiO₂ ≤ 1.0% which ensurs metallurgical purity.
Its Physicals:
Bulk Density: 4.0～4.8 g/cm³
Mohs Hardness: 5.5～6
Excellent Thermal Properties:
Melting Point: 2180°C
Sintering Temperature: >1800°C
Refractoriness: >1900°C
High Thermal Conductivity: Significantly higher than silica sand, accelerating casting cooling and refining grain size.
Low Coefficient of Thermal Expansion: Stable volume under heat, effectively preventing casting defects such as sand inclusions and veins.
Chemical Inertness: Neutral to weakly alkaline (pH 7–9), does not react with molten metals such as iron oxide and manganese steel, and resists alkaline slag corrosion.
Available production sizes:
AFS25-35 AFS35-40 AFS40-45 AFS40-50 AFS45-50 AFS45-55 etc
