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In response to the Alkali Act, the noxious calcium sulfide was converted into calcium carbonate: CaS(s) + CO 2 (g) + H 2 O(l) → CaCO 3 (s) + H 2 S(g) The hydrogen sulfide can be used as a sulfur source for the lead chamber process to produce the sulfuric acid used in the first step of the Leblanc process.
The sulfuric acid dissolves the carbonates in the hardened cement paste (HCP), and also calcium hydroxide (portlandite: Ca(OH) 2) and calcium silicate hydrate (CaO·SiO 2 ·nH 2 O), and causes strength loss, as well as producing sulfates which are harmful to concrete.
Calcium carbonate and formic acid chemical reaction occurs as follows: [11] CaCO 3 + 2CH 2 O 2 → Ca(HCOO) 2 + H 2 O + CO 2. Calcium carbonate and sulfuric acid chemical reaction occurs as follows: [12] CaCO 3 + H 2 SO 4 → CaSO 4 + H 2 O + CO 2. In this last reaction, calcium carbonate reacts with sulfuric acid and produces calcium sulfate ...
Up to the 1970s, commercial quantities of sulfuric acid were produced from anhydrous calcium sulfate. [14] Upon being mixed with shale or marl, and roasted at 1400°C, the sulfate liberates sulfur dioxide gas, a precursor to sulfuric acid. The reaction also produces calcium silicate, used in cement clinker production. [15] [16]
As a noxious byproduct of the Leblanc process, it can be converted to calcium carbonate and hydrogen sulfide, the latter of which can be used as a sulfur source for the lead chamber process to produce the sulfuric acid necessary for the Leblanc process: CaS(s) + CO 2 (g) + H 2 O(l) → CaCO 3 (s) + H 2 S(g)
The same equation relating the concentrations of acid and base applies. The concept of neutralization is not limited to reactions in solution. For example, the reaction of limestone with acid such as sulfuric acid is also a neutralization reaction. [Ca,Mg]CO 3 (s) + H 2 SO 4 (aq) → (Ca 2+, Mg 2+)(aq) + SO 2− 4 (aq) + CO 2 (g) + H 2 O
The calcium salts are soluble and thus washed away during dissolution or solvation. The speed of the descaling action depends on the concentration and acidity or pH of the solution provided. Hydrochloric acid is much stronger than acetic acid, for example, and therefore tends to remove scale faster.
The Leblanc process, which was invented by Nicolas Leblanc around 1790, begins with the decomposition of sodium chloride by sulfuric acid, by which sodium sulfate and hydrochloric acid are produced. The sodium sulfate is afterwards fired with calcium carbonate and coal. Sodium carbonate can be extracted from this mixture by washing the mixture ...