Limestone introduction:

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3).

It is the raw material for the manufacture of quicklime (calcium oxide), slaked lime (calcium hydroxide), cement and mortar.

Limestone rotary kiln is the key equipment for the lime production process in the building materials, its main role is calcining raw materials with high calcium carbonate, such as limestone, dolomite, chalk, shells and other materials to produce lime.

Lime production process:

Limestone in the lime industry is a general term for rocks that contain eighty percent or more of calcium or magnesium carbonates including marble, chalk, oolite, and marl. Further classification is by composition as high calcium, argillaceous (clayey), silicious, conglomerate, magnesian and other limestones, and dolomite.

Uncommon sources of lime are coral, sea shells, calcite, and ankerite. Limestone is extracted from quarries or mines. Part of the extracted stone, selected according to its chemical composition and granulometry, is calcinated at about 1,000 °C (1,830 °F) in different types of lime kilns to produce quicklime according to the reaction: CaCO3 + heat → CaO + CO2.

Before use, quicklime is hydrated, that is combined with water, called slaking so hydrated lime is also known as slaked lime, and is produced according to the reaction: CaO + H2O → Ca(OH).Dry slaking is when quicklime is slaked with just enough water to hydrate the quicklime but remain as a powder and is referred to as hydrated lime. In wet slaking enough water, but not too much, is added to hydrate the quicklime and form a putty referred to as lime putty.