Calcium Hydroxide CAS 1305-62-0

2.Physical and Chemical Properties

• Appearance: White powder
• Melting point: Loses water at approximately 580 °C (decomposes to calcium oxide)
• Density: Approximately 2.24 g/cm³
• Solubility: Slightly soluble in water (about 0.185 g/100 mL at 0 °C, solubility decreases with rising temperature); soluble in acids and glycerol; insoluble in ethanol
• Aqueous solution: Strongly alkaline (saturated limewater pH about 12.4)
• Stability: Stable; reacts with atmospheric CO2 to form calcium carbonate

3.Main Functions and Applications (What are its uses?)

• Water treatment (core application): As the most commonly used alkaline neutralizer, it is widely applied for pH adjustment, water softening, acid wastewater/gas neutralization and flue-gas desulfurization (FGD), efficiently removing SO2 and other acidic pollutants.
• Construction (core application): As the cementing material of mortar, plaster and lime slurry, it is an important material in building and civil engineering, used for masonry, rendering and foundation treatment.
• Chemical industry: An important raw material for calcium carbonate, sodium hydroxide (causticizing process) and bleaching powder.
• Agriculture: Used to ameliorate acidic soil, regulate soil pH and supply calcium nutrients.
• Food: As an acidity regulator, calcium fortifier and firming agent (E526), used in food processing and tofu coagulation.
• Environmental protection: Used for flue-gas desulfurization and acid-gas neutralization to support air-pollution control.
• Pharmaceutical: Calcium hydroxide paste is used for root-canal filling in dentistry, and also as an antacid.
• Leather: Used as a depilatory agent in the liming process.