Hydrated lime, also known as calcium hydroxide (Ca(OH)₂), is created through a two-step process involving limestone and water.
The Hydrated Lime Production Process
The process, outlined below, involves burning limestone and then carefully reacting it with water:
Step 1: Burning Limestone
- Limestone (primarily calcium carbonate, CaCO₃) is heated to a very high temperature, a process called calcination. This converts the limestone into quicklime (calcium oxide, CaO).
Step 2: Quenching with Water
- The resulting quicklime is then reacted, or "quenched," with a controlled amount of water.
- This reaction produces hydrated lime (calcium hydroxide, Ca(OH)₂), also known as slaked lime.
- The chemical reaction is represented by: CaO + H₂O → Ca(OH)₂
Key Points About Hydrated Lime
- Setting: Hydrated lime is not a hydraulic binder. It sets by reacting with carbon dioxide (CO₂) from the air to form calcium carbonate (CaCO₃).
- Chemical Formula: The chemical formula for hydrated lime is Ca(OH)₂.
- Reference Information: Hydrated lime (Ca(OH)2) is produced by burning limestone at high temperatures with subsequent controlled quenching with water. By reaction with CO2 from the air, hydrated lime sets to form calcium carbonate and is therefore not a hydraulic binder.
Summary of Hydrated Lime Production
| Step | Description | Reactants | Products |
|---|---|---|---|
| 1. Calcination | Limestone is heated to high temperatures. | Calcium Carbonate (CaCO₃) | Quicklime (CaO) |
| 2. Quenching | Quicklime reacts with a controlled amount of water. | Quicklime (CaO) + Water (H₂O) | Hydrated Lime (Ca(OH)₂) |
