How much of the carbon dioxide in magnesite is released when I make calcined, dead burned or fused magnesia?

Typically 96 to 98% of the carbon dioxide (CO2) in magnesite is released making calcined magnesia, and nearly 100% for dead burned and fused magnesia, says the Intergovernmental Panel on Climate Change (IPCC). At full release a tonne of magnesium carbonate gives 0.52197 tonnes of CO2.

The three products

• Calcined magnesia: used in agriculture and industry, for example cattle feed supplement, fertilisers, electrical insulation and flue gas desulphurisation. 96 to 98% of the CO2 is released.
• Dead burned magnesia (periclase): used mainly in refractories. Nearly 100% of the CO2 is released with the further heating.
• Fused magnesia: used in refractories and electrical insulation. Nearly 100% released.

Putting it in the formula

Process CO2 = magnesite weighed x magnesium carbonate share x 0.52197 x fraction calcined. For calcined magnesia the guide's range gives 0.96 to 0.98 as the fraction; for dead burned and fused magnesia use about 1.0. Your own loss on ignition test of feed and product shows the real fraction, and replaces the range.

Where it is reported

• Magnesia made for fertiliser is reported under the chemical industry.
• Dead burning of dolomite is reported with lime production where it is dead burned.
• Other magnesia sits in its own mineral industry category, and the guide asks you to avoid double counting with the others.

Fuel is separate

Coal, petcoke, oil or gas in the kilns is a separate Scope 1 line from your fuel invoices.

10,000 tonnes of magnesite at 90% magnesium carbonate

• Magnesium carbonate: 10,000 x 0.90 = 9,000 tonnes; at full release 9,000 x 0.52197 = 4,697.7 tonnes of CO2
• Calcined, 97% released: 4,697.7 x 0.97 = 4,556.8 tonnes
• Dead burned, about 100% released: 4,697.7 tonnes
• The difference between the two products is about 141 tonnes

Feed and assay are example numbers. Use your own weighbridge slips and lab results.

What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records, so kiln fuel and site power are on file. Magnesite tonnes and loss on ignition results come from your lab and stores.

• Carbon calculators
• Magnesite calcination: CO2 per tonne
• Ranchi refractory cluster
• Asansol refractory plant kiln

Sources: IPCC, 2006 Guidelines for National Greenhouse Gas Inventories, Volume 3, Chapter 2: Mineral Industry Emissions

Last reviewed 2026-11-04. The 2006 Guidelines are written for national inventories. A plant's own lab assay, production log and fuel invoices replace these defaults wherever you have them.