1. Construction 

• Mortars and Plasters: Calcium hydroxide is a traditional binder in lime mortars, plasters, and whitewash. It reacts with atmospheric CO₂ to form calcium carbonate, which provides durability and breathability to masonry structures.
• Desulfurization Agent: Used in gas scrubbing systems to remove acidic impurities (e.g., H₂S, CO₂) from refinery gases.
• Drilling Fluid Additive: Maintains alkaline pH in drilling muds to protect equipment and stabilize shale formations.

2. Water Treatment

• pH Adjustment and Softening: Calcium hydroxide raises pH and precipitates heavy metals, phosphates, and hardness ions (like Mg²⁺), making it ideal for drinking water purification and industrial wastewater neutralization.
• Sludge Conditioning: Used to stabilize sewage sludge by raising pH, reducing pathogens, and minimizing odor, which aids in biosolid disposal or reuse.
• Flocculant Aid: Improves coagulation and sedimentation in treatment plants by forming larger flocs, allowing better filtration of suspended particles.

3. Performance Chemicals

• Precursor for Other Calcium Compounds: Used in manufacturing calcium stearate, calcium chloride, calcium hypochlorite, and calcium phosphate, which are widely used in plastics, pharmaceuticals, and disinfectants.
• Neutralizing Agent in Reactions: Used to neutralize acidic waste streams, acid gases (like SO₂), or acidic intermediates in chemical manufacturing processes.

4. Food & Healthcare Ingredients 

• Pickling Agent: Known as pickling lime, it is used to firm cucumbers and other vegetables before pickling.
• Nixtamalization of Corn: Essential in Latin American cuisine, it is used to treat corn kernels, improving nutritional content, digestibility, and making masa for tortillas and tamales.
• Clarification of Raw Sugar: Used to precipitate impurities during sugar refining, helping to clarify cane juice before crystallization.

5. Agrochemicals

• Soil pH Regulator: Applied to acidic soils as a liming agent to raise pH, improving nutrient availability and microbial activity.
• Fungicide Base (Bordeaux Mixture): Combined with copper sulfate to form Bordeaux mixture, a traditional fungicide used in organic farming to protect fruits and vegetables from fungal infections.
• Feed Additive: Used in animal feed supplements as a source of calcium and to neutralize acidic ingredients.

6. Pharmaceuticals

• Excipient and Antacid: Used in pharmaceutical formulations to adjust pH or as an antacid in some over-the-counter products.
• Topical Astringent: In some ointments or pastes, calcium hydroxide helps soothe skin irritation, especially in diaper rash creams or minor skin inflammations.

 7. Metal Treatment 

• Cyanide Recovery and pH Control in Gold Mining: Maintains alkaline conditions to optimize cyanide leaching of gold and prevent the release of toxic gases like HCN.
• Neutralizing Acid Mine Drainage: Used to treat acidic drainage from mines, precipitating metals and raising pH to reduce environmental impact.