Hydrated Lime
Description:
Hydrated lime, also known as slaked lime or calcium hydroxide, is a fine, white or grayish-white powder. It is produced by reacting quicklime (calcium oxide) with water in a process called slaking. Unlike quicklime, hydrated lime is less caustic and has a smoother texture.
Uses:
- Construction:
- As a binder in mortar and plaster for its adhesive and hardening properties.
- To improve the workability of concrete.
- For soil stabilization to improve bearing capacity and reduce shrinkage.
- Water Treatment:
- To raise the pH of water for better flocculation and removal of impurities.
- To neutralize acidic wastewater.
- Agriculture:
- As a soil amendment to adjust pH and provide calcium for plant growth.
- To control some fungal diseases.
- Other Uses:
- In flue gas desulfurization to remove sulfur dioxide from emissions.
- As a flame retardant in some materials.
- In food processing as an anticaking agent and for pH control.
Chemical Composition:
- Primary component: Calcium hydroxide (Ca(OH)2) – typically makes up over 90% by weight.
- May contain minor amounts of:
- Calcium oxide (CaO) – unreacted quicklime from the production process.
- Calcium carbonate (CaCO3) – from the source material or due to carbonation over time when exposed to air.
- Other impurities depending on the source material.
Physical Properties:
- Appearance: Odorless, white or grayish-white powder
- Density: 700-900 kg/m3
- Solubility in Water: Low (around 0.165 grams per 100 grams of water)
- Melting Point: 1076°F (580°C)
- Boiling Point: 5162°F (2850°C)
Safety Information:
- Hydrated lime is a strong alkali and can cause irritation to the skin, eyes, and respiratory system.
- Wear gloves, eye protection, and a respirator when handling hydrated lime, especially in dusty conditions.
- Avoid prolonged or repeated contact with skin.
- Hydrated lime reacts exothermically (with heat generation) with acids. Avoid contact with acids to prevent a violent reaction.
- Keep hydrated lime out of reach of children and pets.
Additional Information:
- Hydrated lime absorbs moisture and carbon dioxide from the air over time. This can reduce its effectiveness in some applications.
- Always consult the manufacturer’s safety data sheet (SDS) for specific handling and storage recommendations for the particular hydrated lime product you are using.
