Доломит (CaMg (CO3) 2), обожженный огнеупор

Calcined dolomite or simply dolomite or dolomite (i.e., CaO + MgO) is a product produced by calcination at relatively low temperatures and is highly porous and reactive. Like other carbonates, upon heating above 900°C dolomite decomposes completely into a mixture of calcium and magnesium oxides, and carbon dioxide:
CaMg(CO₃)₂(s) —> CaO(s) + MgO(s) + 2CO₂(g)

Dead burned dolomite exhibits high refractoriness and can withstand temperatures up to 2300°C. It is widely used as a refractory material wherever steel is refined using basic slag. It is used for original hearth installations in open hearth furnaces as well as for hearth maintenance. These hearths are installed using tar-dolomite ramming mixes and rammed dolomite. Dolomite refractories are also used in electrical furnaces and in the cement industry during clinker manufacture.