Limestone has many uses. It can be used directly as a stone building material, often used for statues. It is also used as a raw material to produce the following for the construction industry:
Limestone is heated in a kiln with sand and sodium carbonate to produce . Limestone can also be heated in a kiln with clay to produce which can mixed with gravel to form . Limestone is mainly the compound calcium carbonate (CaCO3) which is made up of 3 elements:
Limestone is mainly the compound calcium carbonate (CaCO3) which is made up of 3 elements:
During thermal decomposition a compound splits into (decomposes) smaller molecules while being given (thermal) energy. Metal carbonates decompose on heating to give carbon dioxide and the metal oxide. However not all carbonates of metals in Group 1 of the periodic table decompose at the temperatures reached by a Bunsen burner because they are so reactive. Calcium carbonate can be decomposed by heating (thermal decomposition) to make calcium (quicklime) and carbon dioxide.
Calcium carbonate can be decomposed by heating (thermal decomposition) to make calcium (quicklime) and carbon dioxide.
A lot of energy is required to convert limestone into quicklime and currently that results in producing carbon dioxide from the burning of fossil fuels. In addition to that the limestone itself release carbon dioxide as it decomposes. The production of cement alone accounts for 5% of global man-made CO2 emissions!
The quicklime (calcium oxide) can react with water to produce slaked lime (calcium hydroxide).
Slaked lime can be used to neutralise some of the acidity found in some soils and lakes, espeacially those affected by acid rain. Slaked lime can also be disolved in more water to form Calcium Hydroxide Solution, also known as lime water which is used to test for carbon dioxide. For the construction industry however, the slaked lime is used to create lime mortar when mixed with .and historically lime whitewash 'paints'.
