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The inverse comproportionation reaction is the reaction occurring in the Claus process used for desulfurization of oil and gas crude products in the refining industry: H 2 S + 3 / 2 O 2 → SO 2 + H 2 O. By rewriting the last reaction in the inverse direction one obtains a reaction consistent with what is observed in the lime sulfur global ...
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]
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. [19] H 2 SO 4 + Ca(OH) 2 → CaSO 4 + 2 H 2 O H 2 SO 4 + CaO·SiO 2 ·n H 2 O ...
Calcium hydroxide is modestly soluble in water, as seen for many dihydroxides. Its solubility increases from 0.66 g/L at 100 °C to 1.89 g/L at 0 °C. [8] Its solubility product K sp of 5.02 × 10 −6 at 25 °C, [1] its dissociation in water is large enough that its solutions are basic according to the following dissolution reaction:
Slaked lime (calcium hydroxide) or limestone (calcium carbonate) may be worked into soil that is too acidic for plant growth. Fertilizers that improve plant growth are made by neutralizing sulfuric acid (H 2 SO 4) or nitric acid (HNO 3) with ammonia gas (NH 3), making ammonium sulfate or ammonium nitrate. These are salts utilized in the fertilizer.
SO 2 is an acid gas, and, therefore, the typical sorbent slurries or other materials used to remove the SO 2 from the flue gases are alkaline. The reaction taking place in wet scrubbing using a CaCO 3 slurry produces calcium sulfite (CaSO 3) and may be expressed in the simplified dry form as: CaCO 3 +SO 2 → CaSO 3 + CO 2
Solutions containing magnesium sulfate are generally more aggressive, for the same concentration. This is because magnesium also takes part in the reactions, replacing calcium in the solid phases with the formation of brucite (magnesium hydroxide) and magnesium silicate hydrates. The displaced calcium precipitates mainly as gypsum.
The heat of reaction is then minus the sum of the standard enthalpies of ... Calcium hydroxide: Solid Ca ... Gas SO 3: −395.7 Sulfuric acid: Liquid H 2 SO 4: −814 ...