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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 dioxide (CO 2), leaving quicklime behind. This is also one of the few chemical reactions known in prehistoric times. [8] CaCO 3 (s) → CaO(s) + CO 2 (g)
Each mole of CO 2 (44 g) reacts with one mole of calcium hydroxide (74 g) and produces one mole of water (18 g). The reaction can be considered as a strong-base-catalysed, water-facilitated reaction. [5] The reaction mechanism of carbon dioxide with soda lime can be decomposed in three elementary steps: 1) () (CO 2 dissolves in water – slow ...
Rotary lime kiln (rust-colored horizontal tube at right) with preheater, Wyoming, 2010 Traditional lime kiln in Sri Lanka. A lime kiln is a kiln used for the calcination of limestone (calcium carbonate) to produce the form of lime called quicklime (calcium oxide). The chemical equation for this reaction is: CaCO 3 + heat → CaO + CO 2
Carbonatation is a slow process that occurs in concrete where lime (CaO, or Ca(OH) 2 ) in the cement reacts with carbon dioxide (CO 2) from the air and forms calcium carbonate. The water in the pores of Portland cement concrete is normally alkaline with a pH in the range of 12.5 to 13.5.
Pure lime is soluble in water containing carbonic acid, a natural, weak acid which is a solution of carbon dioxide in water and acid rain so it will slowly wash away, but this characteristic also produces autogenous or self-healing process where the dissolved lime can flow into cracks in the material and be redeposited, automatically repairing ...
When water that contains dissolved calcium carbonate is warmed, CO 2 leaves the water as gas, this reduces the amount involved in the reaction causing the equilibrium of bicarbonate and carbonate to re-balance to the right, increasing the concentration of dissolved carbonate.
Calcium carbide is produced industrially in an electric arc furnace from a mixture of lime and coke at approximately 2,200 °C (3,990 °F). [5] This is an endothermic reaction requiring 110 kilocalories (460 kJ) per mole [6] and high temperatures to drive off the carbon monoxide. This method has not changed since its invention in 1892:
One idea is to react carbon dioxide, produced perhaps by the combustion of coal, to form solid carbonates (such as sodium bicarbonate) that could be permanently stored, thus avoiding carbon dioxide emission into the atmosphere. [20] [21] The Solvay process could be modified to give the overall reaction: 2 NaCl + CaCO 3 + CO 2 + H 2 O → 2NaHCO ...