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Calcium carbonate (limestone or chalk) decomposes into calcium oxide and carbon dioxide when heated. The chemical reaction is as follows: CaCO 3 → CaO + CO 2 The reaction is used to make quick lime, which is an industrially important product. Another example of thermal decomposition is 2Pb(NO 3) 2 → 2PbO + O 2 + 4NO 2.
Other carbonates will decompose when heated to produce their corresponding metal oxide and carbon dioxide. [5] The following equation is an example, where M represents the given metal: MCO 3 → MO + CO 2. A specific example is that involving calcium carbonate: CaCO 3 → CaO + CO 2. Metal chlorates also decompose when heated.
Calcium carbonate is used in the production of calcium oxide as well as toothpaste and has seen a resurgence as a food preservative and color retainer, when used in or with products such as organic apples. [58] Calcium carbonate is used therapeutically as phosphate binder in patients on maintenance haemodialysis. It is the most common form of ...
Calcium oxide is a crucial ingredient in modern cement, and is also used as a chemical flux in smelting. Industrial calcination generally emits carbon dioxide (CO 2). A calciner is a steel cylinder that rotates inside a heated furnace and performs indirect high-temperature processing (550–1150 °C, or 1000–2100 °F) within a controlled ...
Calcium oxide is usually made by the thermal decomposition of materials, such as limestone or seashells, that contain calcium carbonate (CaCO 3; mineral calcite) in a lime kiln. This is accomplished by heating the material to above 825 °C (1,517 °F), [ 6 ] [ 7 ] a process called calcination or lime-burning , to liberate a molecule of carbon ...
The reaction between hydrochloric acid and calcium carbonate (limestone or chalk) is shown below: CaCO 3 + 2 HCl → CaCl 2 + H 2 CO 3. The carbonic acid (H 2 CO 3) then decomposes to water and CO 2: H 2 CO 3 → CO 2 + H 2 O. Such reactions are accompanied by foaming or bubbling, or both, as the gas is released.
At 450-550 °C the cement hydrate decomposes, yielding calcium oxide. Calcium carbonate decomposes at about 600 °C. Rehydration of the calcium oxide on cooling of the structure causes expansion, which can cause damage to material which withstood fire without falling apart.
As new cold water with dissolved calcium carbonate/bicarbonate is added and heated, the process continues: CO 2 gas is again removed, carbonate concentration increases, and more calcium carbonate precipitates. Scale is often colored because of the presence of iron-containing compounds.