High-Calcium Limestone (High Grade)

High-calcium limestone is a high-purity sedimentary carbonate rock composed predominantly of calcium carbonate (CaCO₃), typically in the range of 95–99%, with very low magnesium and impurity content.

It is the preferred limestone grade for applications requiring chemical purity, predictable reactivity, and high lime yield, including cement production, steelmaking, chemical processing, glass manufacturing, and environmental systems.

Low magnesium and silica levels clearly distinguish high-calcium limestone from dolomitic and ordinary limestone grades.

Strengthening & Metallurgical Behavior

Strengthening behavior:
Mechanical strength is derived from dense calcite crystal packing and low pore connectivity. Durability can be further enhanced through:

• Sintering
• Cement stabilization (aggregate use)

Naturally durable and weather-resistant, high-calcium limestone performs reliably in both structural and industrial environments.

Metallurgical behavior:
High-calcium limestone is an excellent flux material. On heating, it decomposes as:

CaCO₃ → CaO + CO₂

This reaction produces high-reactivity quicklime (CaO) with:

• High lime yield
• Low slag contamination
• Efficient sulfur and phosphorus removal

Its predictable chemistry makes it the preferred limestone for steelmaking and non-ferrous metallurgy.

Key Characteristics

✔ Very high CaCO₃ purity
✔ Low magnesium and silica content
✔ Predictable calcination behavior
✔ High lime reactivity
✔ Uniform chemistry
✔ Excellent consistency for industrial process control

Refining & Processing Properties

Quarrying:
• Open-pit quarrying
• Controlled blasting to preserve purity zones
• Selective mining for grade consistency

Processing:
• Crushing and screening
• Washing for impurity removal
• Grinding (powder applications)
• Calcination (lime production)
• Hydration (slaked lime)
• Pelletizing / briquetting (metallurgical use)

Thermal processing:
High-calcium limestone requires lower fuel consumption during calcination compared to dolomitic limestone and produces:

• Quicklime (CaO)
• Hydrated lime (Ca(OH)₂)

Available Forms

✔ Quarry blocks
✔ Crushed stone
✔ Aggregates
✔ Ground calcium carbonate (GCC)
✔ High-calcium quicklime (CaO)
✔ Hydrated lime (Ca(OH)₂)
✔ Pellets and briquettes
✔ Lime slurry (milk of lime)

Applications

Construction & Infrastructure:
• Cement manufacturing
• Concrete aggregates
• Road base material
• Dimension stone

Metallurgical & Industrial:
• Steelmaking flux
• Non-ferrous metallurgy
• Glass manufacturing
• Chemical feedstock (CaO, Ca(OH)₂)
• Calcium carbide production

Agriculture:
• Soil acidity correction
• Calcium nutrient source
• Animal feed additive

Environmental:
• Flue gas desulfurization (FGD)
• Water and wastewater treatment
• Acid neutralization
• Sludge stabilization

Advantages of High-Calcium Limestone

✔ Highest lime yield
✔ Lower energy consumption during calcination
✔ Superior metallurgical performance
✔ Consistent chemical quality
✔ Widely available and cost-effective
✔ Essential industrial raw material

Why Choose High-Calcium Limestone

High-calcium limestone is the optimal choice for cement plants, lime kilns, and steel operations where low magnesium content and high CaO availability are critical. Its consistent chemistry reduces slag volume, improves process efficiency, and ensures reliable performance across heavy industries.

Quick Comparison