Calcium Carbide 25–50mm and 50–80mm: Export Grades, Gas Yield and Applications

1. Product Overview

Calcium carbide (CaC₂) is an industrial chemical material produced by the reaction of quicklime (CaO) and carbon materials in an electric arc furnace at approximately 2000–2200°C.

After smelting, the carbide is cooled, crushed and screened into different lump sizes. Among export markets, 25–50mm and 50–80mm calcium carbide lumps are two commonly requested specifications.

Both sizes are designed for industrial applications requiring:

Stable acetylene generation

Suitable reaction speed

Low fines generation

Reliable transportation and storage performance

The selection between 25–50mm and 50–80mm mainly depends on the customer's equipment design, gas consumption rate and handling requirements.

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2. Typical Specifications of Calcium Carbide Lump

Parameter	25–50mm Grade	50–80mm Grade
Product Form	Calcium carbide lumps	Calcium carbide lumps
Size Range	25–50 mm	50–80 mm
Size Distribution	≥95% within range	≥95% within range
Acetylene Gas Yield	≥295 L/kg	≥295 L/kg
CaC₂ Content	≥93%	≥93%
Sulfur (S)	≤0.20%	≤0.20%
Phosphorus (P)	≤0.15%	≤0.15%
Moisture	≤0.50%	≤0.50%
Ash Content	≤3.0%	≤3.0%
Appearance	Gray-black crystalline lumps	Gray-black crystalline lumps

Note:
Actual specifications can be customized according to application requirements. Calcium carbide gas-yield grades are commonly classified according to GB 10665, including 295 L/kg, 285 L/kg, 275 L/kg and 255 L/kg.

Each shipment should be verified through a Certificate of Analysis (COA) showing actual CaC₂ content, gas yield and impurity levels.

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3. Calcium Carbide Size Selection Guide

3.1 Calcium Carbide 25–50mm

The 25–50mm grade provides a balance between reaction speed and handling stability.

Typical advantages:

Faster reaction compared with larger lumps

Suitable acetylene production efficiency

Good compatibility with medium-sized generators

Easier feeding and handling

Common applications:

Medium-scale acetylene generators

Welding gas production

Chemical processing systems

Industrial users with moderate gas demand

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3.2 Calcium Carbide 50–80mm

The 50–80mm grade is preferred for applications requiring larger lump size and stable long-term operation.

Typical advantages:

Lower fines generation

Better mechanical strength during transportation

More controlled reaction rate

Suitable for continuous industrial feeding systems

Common applications:

Large acetylene production plants

Chemical manufacturing facilities

Heavy-duty industrial gas systems

Large-scale industrial users

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4. Calcium Carbide Applications

4.1 Acetylene Production

The primary application of calcium carbide is acetylene generation.

Chemical reaction:

CaC₂ + 2H₂O → C₂H₂ + Ca(OH)₂

Generated acetylene is used in:

PVC production

Vinyl chloride monomer (VCM)

Chemical intermediates

Synthetic material manufacturing

Stable gas yield is important for continuous chemical production.

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4.2 Steelmaking and Metallurgy

Calcium carbide is used in metallurgical applications as a reducing agent and desulfurization material.

Typical functions:

Removing sulfur from molten steel

Supporting cleaner steel production

Improving process stability during ladle treatment

Steel plants usually evaluate:

CaC₂ content

Gas yield

Particle size

Sulfur and phosphorus levels

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4.3 Foundry Applications

In certain foundry processes, calcium carbide may be used as a chemical reagent for molten metal treatment.

Application performance depends on:

Metal composition

Treatment method

Process parameters

Foundries should select the appropriate carbide grade according to their established operating procedures.

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4.4 Welding and Cutting

Calcium carbide-generated acetylene is used for oxy-acetylene equipment in:

Steel plate cutting

Ship repair

Pipeline maintenance

Industrial welding operations

Different lump sizes can be selected depending on generator design and gas demand.

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5. 25–50mm vs 50–80mm Calcium Carbide Comparison

Feature	25–50mm	50–80mm
Reaction Speed	Faster	More controlled
Gas Output Control	Good	Very stable
Handling Strength	Good	Higher
Fines Generation	Moderate	Lower
Recommended Use	Medium-scale systems	Large-scale continuous systems

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6. Export Packaging and Logistics

Packaging Options

Common export packaging includes:

50 kg moisture-proof steel drums

1-ton sealed bulk bags

Customized bulk packaging for large orders

Calcium carbide packaging must prevent moisture exposure because contact with water generates flammable acetylene gas.

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Shipping Requirements

Calcium carbide is classified as a water-reactive hazardous material.

Export shipments require:

Suitable dangerous goods packaging

Moisture protection

Compliance with transportation regulations

Common trade terms:

FOB

CIF

CFR

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Required Documents

International buyers typically request:

Certificate of Analysis (COA)

Safety Data Sheet (SDS)

Gas yield test report

Packing list

Shipping documents

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7. Calcium Carbide Export Pricing Factors

Calcium carbide prices vary depending on:

Factor	Influence
CaC₂ Grade	Higher purity grades generally have higher value
Gas Yield Class	295 L/kg grade requires higher performance
Lump Size	Customized sizes may affect processing cost
Packaging	Drum and bulk packaging have different costs
Order Quantity	Large-volume orders may receive different terms

For an accurate quotation, buyers should provide:

Required size (25–50mm or 50–80mm)

Gas yield requirement

CaC₂ percentage

Packaging preference

Destination port

Order quantity

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FAQ About Calcium Carbide Lump Sizes

1. What is the difference between 25–50mm and 50–80mm calcium carbide?

The main difference is particle size. Smaller lumps generally react faster, while larger lumps provide more controlled reaction and better handling strength.

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2. Which calcium carbide size is better for acetylene production?

The suitable size depends on generator design and operating conditions. Both 25–50mm and 50–80mm can provide stable acetylene generation when matched correctly.

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3. What does 295 L/kg gas yield mean?

It indicates that one kilogram of calcium carbide can generate approximately 295 liters of acetylene gas under specified testing conditions.

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4. Can calcium carbide size be customized?

Yes. Common sizes include 10–25mm, 25–50mm, 50–80mm and other customized lump sizes.

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5. What documents should suppliers provide?

Export suppliers should provide COA, SDS, product specifications and batch testing information.

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