Calcined Magnesite

Calcined Magnesite from Pakistan

Calcined magnesite is produced by thermal decomposition of raw magnesite (MgCO₃) in shaft or rotary kilns. The calcination temperature determines the product type and properties. Caustic-calcined magnesia (CCM) is produced at 700-1000°C, yielding a reactive, porous MgO product. Dead-burned magnesia (DBM) is produced at 1500-1800°C, yielding a dense, sintered MgO product with high refractoriness. Pakistan has dedicated magnesite calcination facilities near its mining areas in Khyber Pakhtunkhwa and Balochistan, producing both CCM and DBM grades for domestic and export markets.

Specifications

Caustic-Calcined Magnesia (CCM)

• MgO: 80-92%

• SiO₂: 2-6%

• CaO: 1-4%

• Fe₂O₃: 0.5-3%

• LOI: 2-8%

• Bulk Density: 1.5-2.2 g/cm³

• Reactivity: High (citric acid activity 15-60 seconds)

• Colour: White to light grey

Dead-Burned Magnesia (DBM)

• MgO: 90-96%

• SiO₂: 1-4%

• CaO: 1-3%

• Fe₂O₃: 0.5-2%

• LOI: < 1%

• Bulk Density: 3.1-3.4 g/cm³

• Refractoriness: > 2000°C

• Colour: Light grey to grey-brown

Available Forms

• Calcined lumps: 0-50 mm, 10-30 mm, 5-15 mm

• Granules: 0-3 mm, 1-5 mm, 3-8 mm

• Powder: 100, 200, 325 mesh

• Custom sizing available

Industrial Uses

CCM Applications:

• Sorel cement and MgO boards: CCM is mixed with magnesium chloride to produce magnesium oxychloride (Sorel) cement for seamless industrial flooring, fire-resistant construction boards, and decorative terrazzo surfaces

• Agriculture: CCM is used as a fast-acting magnesium fertilizer and soil pH buffer for acidic soils. Higher reactivity compared to raw magnesite ensures quicker nutrient availability

• Animal feed: CCM is the preferred form of magnesium supplement in livestock, poultry, and aquaculture feed due to its high MgO content and bioavailability

• Environmental treatment: CCM is used for acid mine drainage neutralization, industrial wastewater treatment, heavy metal precipitation, and flue gas desulfurization

• Chemical processing: Feedstock for producing magnesium sulphate, magnesium hydroxide (milk of magnesia), magnesium chloride, and other magnesium compounds

• Rubber and plastics: CCM is used as a vulcanization accelerator in rubber and as a flame retardant additive in plastics

DBM Applications:

• Basic refractory bricks: DBM is the primary raw material for magnesia-carbon (MgO-C), magnesia-chrome (MgO-Cr₂O₃), and magnesia-spinel refractory bricks used in steelmaking BOF converters, EAF furnaces, steel ladles, and cement rotary kilns

• Refractory castables and monolithics: DBM aggregates and fines are used in castable, ramming, and gunning mixes for hot repairs and new linings in steelmaking and non-ferrous smelting

• Steelmaking flux: DBM is added to steelmaking slag to raise MgO levels, protecting refractory linings and improving slag chemistry

• Glass production: DBM is used in glass tank refractory linings and as a minor batch ingredient in specialty glass

Quality Assurance

Each lot includes a Certificate of Analysis reporting MgO, SiO₂, CaO, Fe₂O₃, Al₂O₃, LOI, bulk density, and particle size distribution. CCM lots also report reactivity (citric acid activity). DBM lots report apparent porosity and refractoriness. Pre-shipment samples are provided for buyer approval. Third-party inspection (SGS, Intertek, or equivalent) can be arranged on request.