Understanding Bulk Density: Calcium Carbonate, Quick Lime, and Hydrated Lime
Bulk density is a critical property in industries dealing with powder and granular materials—such as construction, agriculture, mining, and chemicals. It impacts storage, transport, mixing, and application processes. This article explains what bulk density is and compares the bulk densities of Calcium Carbonate (Limestone), Quick Lime (Calcium Oxide), and Hydrated Lime (Calcium Hydroxide).
Key Insights
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Calcium Carbonate is the densest in terms of loose bulk among the three.
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Quick Lime has a moderate bulk density but the highest true density.
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Hydrated Lime is the lightest in bulk form due to its fluffy, powdery texture.
These differences affect everything from storage silo sizing to pneumatic conveying system design and should be considered when handling or using lime-based materials.
What is Bulk Density?
Bulk density refers to the mass of a material per unit volume, including the air space between particles. It is usually expressed in:
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kg/m³ (kilograms per cubic meter)
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g/cm³ (grams per cubic centimeter)
There are typically two types:
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Loose bulk density – the material in its natural, unpacked state
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Tapped (compacted) bulk density – after vibration or mechanical compaction
1. Calcium Carbonate (CaCO₃ – Limestone)
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Loose bulk density: ~ 800 – 1,200 kg/m³
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Tapped bulk density: ~ 1,200 – 1,600 kg/m³
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True density (particle density): ~ 2,710 kg/m³
Calcium carbonate is a dense and relatively heavy powder. It’s widely used in construction (as aggregate or filler), agriculture (soil amendment), and chemical industries.
2. Quick Lime (CaO – Calcium Oxide)
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Loose bulk density: ~ 500 – 900 kg/m³
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Tapped bulk density: ~ 900 – 1,200 kg/m³
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True density: ~ 3,300 – 3,400 kg/m³
Quick lime is produced by heating limestone in a kiln. It’s lighter and more reactive than limestone. Its bulk density is lower due to its porous and irregular structure after calcination.
3. Hydrated Lime (Ca(OH)₂ – Calcium Hydroxide)
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Loose bulk density: ~ 300 – 600 kg/m³
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Tapped bulk density: ~ 600 – 900 kg/m³
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True density: ~ 2,240 – 2,340 kg/m³
Hydrated lime is formed by adding water to quick lime (a process called slaking). It's a fluffy, fine powder with the lowest bulk density among the three due to its expanded structure.
Comparison Table
| Property | Calcium Carbonate (CaCO₃) | Quick Lime (CaO) | Hydrated Lime (Ca(OH)₂) |
|---|---|---|---|
| Loose Bulk Density | 800 – 1,200 kg/m³ | 500 – 900 kg/m³ | 300 – 600 kg/m³ |
| Tapped Bulk Density | 1,200 – 1,600 kg/m³ | 900 – 1,200 kg/m³ | 600 – 900 kg/m³ |
| MAXIMUM LOADING IN 20FT CONTAINER | 28 TONS | 28 TONS | 20-24 TONS |
Mr. Steve (International Sales Manager)
