Foundry Applications of Perlite

Foundry Applications of Perlite — Slag Coagulation & High-Temperature Stability

In foundry operations, expanded perlite serves as a slag coagulant and insulating cover material. Its low density, high porosity, and thermal stability above 1000°C enable efficient slag separation, reduced heat loss, and enhanced metal quality.

1. What Are the Foundry Applications of Perlite?

Perlite is utilized in metal casting for:

• 1.1 Slag Coagulation Process: Increases slag volume, enhances separation, and makes skimming easier.
• 1.2 Insulating Cover: Minimizes heat loss, helps prevent oxidation, and keeps melt temperature stable.
• 1.3 Mold and Core Additive: Enhances collapsibility and minimizes casting defects.

2. Functional Behavior in Foundries

3. How Perlite Functions as a Slag Coagulant

3.1 Slag Contact
It floats due to its low density.
3.2 Thermal Reaction
The surface softens slightly.
3.3 Coagulation Process
Slag particles stick to the perlite.
3.4 Removal
The coagulated slag can be skimmed easily.

4. Factors Influencing Foundry Performance

4.1 Density
Lower density results in better flotation.
4.2 Particle Size
Coarse grades offer better slag capture.
4.3 Expansion Quality
Uniform cellular structure gives stable insulation.

5. Performance in Applications

5.1 Steel and Iron Casting
High slag removal efficiency.
5.2 Aluminum Casting
Excellent oxidation prevention.
5.3 Copper and Brass
High thermal stability.
5.4 Ladle Insulation
Significantly reduced heat loss.

6. Geological Influences

• Glass chemistry
• Natural porosity levels
• Hydration history

7. Regional Foundry Characteristics

8. FAQ

Q: Does perlite react with molten metals?
No — it is chemically inert.
Q: Does density affect slag removal?
Yes — a lower density improves flotation.
Q: Why does foundry performance vary?
Due to PSD and density differences.