1. Construction 

• Cement and Mortar Production: Calcium oxide is a key component in the manufacturing of Portland cement and lime mortars. It contributes to setting and strength development by reacting with water to form calcium hydroxide, which then reacts with carbon dioxide in air to harden.
• Soil Stabilization: Used to stabilize and strengthen soil for road construction by reducing moisture content, increasing bearing capacity, and forming cementitious compounds with silicates and aluminates in clay.
• Asphalt Modification: Acts as an anti-stripping agent in asphalt mixtures, improving adhesion between bitumen and aggregates, thus increasing pavement lifespan.

2. Metal Treatment 

• Fluxing Agent in Steel and Iron Making: Calcium oxide is added to blast furnaces and basic oxygen furnaces to remove impurities like silica, phosphorus, and sulfur by forming slag. This helps produce high-quality steel.
• pH Adjuster in Smelting: Used to maintain basic conditions during metal extraction and purification processes.

3. Performance Chemicals

• Precursor for Calcium Compounds: Used in the production of chemicals like calcium hydroxide (slaked lime), calcium carbide, calcium chloride, and others. These are further used in diverse applications like refrigerants, water treatment, and desiccants.
• Reagent in Organic Synthesis: Employed in various drying, desulfurization, and neutralization reactions due to its strong basic and desiccant properties.

4.  Pulp & Paper Solutions

• Recausticizing in Kraft Process: Used in the regeneration of white liquor (NaOH) in the Kraft pulping process, where it reacts with sodium carbonate to form sodium hydroxide and calcium carbonate.
• Brightness and Filler Control: Contributes to fiber bleaching and acts as a pH modifier in various paper coating and sizing processes.

 5. Agrochemicals

• Soil pH Modifier (Agricultural Lime): Applied to acidic soils to raise pH, enhancing nutrient availability and microbial activity, which boosts crop yield and soil health.
• Insecticide and Fungicide Carrier: Sometimes used as a carrier or base for powdered pesticides and fungicides due to its drying and binding capacity.

6. Food & Healthcare Ingredients

• Acidity Regulator (E529): Permitted in small quantities as a pH control agent and processing aid in sugar refining, baking, and flour processing.
• Used in Pickling and Corn Nixtamalization: Used in Latin American food processing (e.g., tortilla production) to treat maize, improving digestibility and nutritional content.