Thermal decomposition of limestone
Limestone is mainly Calcium Carbonate (CaCO3) Thermal Decomposition is the breaking down of a substance through heat. Thermal decomposition of CaCO3 produces Calcium Oxide (CaO) a useful substance used in building and construction.
Limestone is heated in a 'rotary lime kiln': a rotating drum; the movement makes sure that the Calcium Carbonate is thouroughly mixed with the hot air so that is decomposes completley.
As limestone travels through the kiln, the temperature increases and it breaks down to produce CaO and CO2 . Here's the formula for the process:
CaCO3 > CaO +CO2, Calcium Carbonate (limestone) > Calcium Oxide + Carbon Dioxide
Limestone, like all other metal carbonates, reacts with acid to form a salt and water. The aftermath of these reactions can be seen on corroded limestone statues.
Metal Carbonate + Acid > Salt + Water + Carbon Dioxide Calcium Carbonate + Sulfiric Acid (in acid rain)>Calcium Sulfide+Water+Carbon Dioxide
Reactions of limestone
Like all other metal carbonates, Calcium Carbonate goes through thermal decomposition to produce a metal oxide and carbon dioxide:
metal carbonate > metal oxide + carbon dioxide Calcium Carbonate > Calcium Oxide + Carbon Dioxide Copper Carbonate > Copper Oxide + Carbon Dioxide
The Calcium Oxide produced here reacts with water to produce Calcium Hydroxide (Ca (OH) 2 . Calcium Oxide + Water > Calcium Hydroxide ( CaO + H2O > Ca (OH)2))
Calcium Hydroxide, once also added to water, becomes Calcium Hydroxide solution. AKA, limewater.
Limewater is known to be a test for carbon dioxide. This is because once carbon dioxide is added to calcium hydroxide (limewater) it reacts to form Calcium Carbonate (precipitate) and water Calcium Hydroxide + Carbon Dioxide > Calcium Carbonate + Water Ca (OH) 2 + CO2 > CaCO3 + H2O
The Limestone Reaction Cycle
Cement, Motar and Concrete
Egyptian Motar = [ HEAT(Limestone) ] + Water
Roman Motar = [ HEAT(Limestone) ] + Water + Sand + Calcium Hydroxide Egyptian Motar + Sand + Ca (OH) 2
Calcium Hydroxide allows the motar to harden even in wet conditions as it reacts with the CO2 in the air to produce CaCO3 and water
Calcium Hydroxide + Carbon Dioxide > Calcium Carbonate + Water Ca (OH) 2 + CO2 > CaCO3 + H2O
Cement = Powdered Limestone + Powdered Clay
^ HEAT IN KILN ^
Concrete = Cement + Sand + Water + Aggregate ( small stones / crushed rocks )
(Motar + Aggregate)
Reinforced Concrete = Concrete > Steel Rods