Burnt dolomite is a result of calcinations of natural dolomite lumps which contains 25% to 28% CaCO3 and 15% to 18% MgCO3. On calcination, calcium oxide contains becomes 50% to 55% and Magnesium Contains 30% to 35%.
CaCO3 • MgCO3 + Heat = CaO • MgO + 2CO2
Dolomitic limestone (dolomite) has normally been formed by the replacement of some of the calcium in limestone with magnesia, a process known as dolomitisation. Theoretically dolomitic lime should be a stoichiometric mixture of CaO and MgO, i.e. 58% CaO and 42% MgO. In practice, because of impurities and differing levels of dolomitisation, commercial products normally contain 30 - 35 % MgO .
It is the best catalyst and base chemical for steel plants.