What is the Difference Between Quicklime and Hydrated Lime?

The main differences between quicklime and hydrated lime are their reactivity and chemical composition. Both are calcium compounds, but they have distinct properties and uses:

• Quicklime: Also known as calcium oxide, quicklime has the chemical formula CaO. It is produced by thermally decomposing limestone, a process known as calcination. Quicklime is a white, caustic, alkaline substance with a heavy density (1 g/cm³). It is used in various applications, such as the production of aerated concrete blocks, glass, and organic chemicals.
• Hydrated Lime: Also known as calcium hydroxide, hydrated lime has the chemical formula Ca(OH)₂. It is produced by adding water to quicklime, which undergoes a process called slaking. Hydrated lime is a colorless crystal with a density of 0.5 g/cm³. It is primarily used in flue gas treatment, neutralizing industrial wastewater, and soil rehabilitation.

Choosing between quicklime and hydrated lime depends on factors such as the feed rate required by the process and the desired reactivity of the powder. In systems that demand large quantities of lime, quicklime is preferred due to its higher density, while hydrated lime is used when the lime consumption is low or medium.

Comparative Table: Quicklime vs Hydrated Lime

The main differences between quicklime and hydrated lime are their reactivity and chemical composition. Here is a comparison table highlighting their differences:

Quicklime, also known as calcium oxide, is a corrosive and reactive substance produced by the thermal decomposition of limestone. Hydrated lime, also known as calcium hydroxide, is derived from quicklime by adding water. When quicklime reacts with water, it produces calcium hydroxide in a process called slaking, which is then used in various applications. The choice of using quicklime or hydrated lime depends on the specific process requirements, such as lime consumption rate and reactivity.