Opta Waive


As the North American representative for a leading supplier of Chromite ore and sands in South Africa, Opta Minerals offers superior quality chromite sand to the steel, foundry and refractory industry.

At all stages of our supply processes stringent quality control measures are employed to assure that this critical mineral is on target with specification.

Chromite, as is indicated by its early crystallization, is resistant to the altering affects of high temperatures and pressures. These characteristics explain the use of chromite as a heat conductive foundry molding sand, which allows localized or general chilling of castings to improve their integrity.


Advantages of Chromite

  • High density,
  • Good for chilling casting
  • Prevent hot tears

TYpical Uses:

  • Used to harden steel, to manufacture stainless steel and to form alloys
  • Used in plating to produce a hard, beautiful surface and to prevent corrosion.
  • Used by the aircraft and other industries for anodising aluminium
  • The refractory industry uses chromite for forming molds and shapes, as it has a high melting point, moderate thermal expansion, and stable crystalline structure

Technical Specifications

Symbol Name Percentage
Cr2O3 (Chromium Oxide) 46.42
Fe2O3 (Iron Oxide) 27.20
AL2O3 (Aluminum Oxide) 14.80
MgO (Magnesium Oxide) 9.85
SiO2 (total) (Silicon Dioxide) 0.75
TiO2 (Titanium Oxide) 0.67
MnO (Manganese Oxide) 0.23
CaO (Calcium Oxide) 0.22
P2O5 (Phosphorus Pentoxide) 0.05
Na2O (Sodium Oxide) 0.03
K2O (Potassium Oxide) 0.02
LOI (Loss On Ignition) 0.15


Colour: Shiny black
Specific Gravity: 4.4
Bulk Density (loose) 163 lb/ft3
Bulk Density (compacted) 181 lb/ft3
Grain Shape Sub-angular
Melting Point (OF) 3350 - 4000
Melting Point (OC) 1850 - 2200
Solubility Negligible


  • 50 lb paper bags, 100 lb paper bags
  • 3000 lb Super Sacs
  • Bulk (blower truck or rail hopper cars)



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