Magnesium oxide, from natural magnesite or from seawater and brine, calcined at roughly 1800 C or higher into dense periclase grain. Firing it dead makes it far less reactive with water and slag than caustic-calcined magnesia burned at lower temperature. It is the base of magnesia brick, gunning mixes and tundish linings, while fused magnesia from arc furnaces goes into premium magnesia-carbon brick.
Gun mix is 90 percent dead-burned magnesia, store it in the dry shed or it'll hydrate.
Also heard as
- DBM
- sintered magnesia
- periclase
Related terms
Basic refractory
Refractory based on magnesia, lime or dolomite that resists basic slags with high lime-to-silica ratios.
Magnesia-carbon brick
Resin-bonded brick of magnesia and graphite, the workhorse lining of BOFs, electric arc furnaces and ladle slag lines.
Hydration
Reaction of magnesia or lime in a refractory with water or humidity, causing swelling, cracking and dusting.
Mag
Clipped shop word for magnesia, magnesia brick or a magnesia-based mix.