Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral, forams and molluscs.Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO 3).
Several different types of kilns are used for the calcination process. These kilns can be rotary kilns or shaft kilns. The type of the kiln to be selected strongly depend on the characteristics of the limestone, anticipated production rate, cost of fuel, investment costs, available fuel, local conditions, infrastructure and other things.
Dolomitization: Dolomitization,, process by which limestone is altered into dolomite; when limestone comes into contact with magnesium-rich water, the mineral dolomite, calcium and magnesium carbonate, CaMg(CO3)2, replaces the calcite (calcium carbonate, CaCO3) in the rock, volume for volume.