Plaster Grade Gypsum

Plaster Grade Gypsum is a high-purity form of calcium sulfate dihydrate (CaSO₄·2H₂O) specifically selected and processed for the manufacture of calcined gypsum (Plaster of Paris) and specialty plasters. Unlike cement-grade gypsum, which acts only as a setting regulator, plaster-grade gypsum is used as a primary binder material.

Strengthening & Metallurgical Behavior

Strengthening behavior:
Plaster-grade gypsum gains strength through hydration recrystallization:

CaSO₄·½H₂O + 1½H₂O → CaSO₄·2H₂O

Interlocking gypsum crystals form a rigid, cohesive matrix. Strength is enhanced by:

• Controlled calcination
• Fine particle size distribution
• Fiber reinforcement or polymer modifiers

Metallurgical behavior:
🚫 No metallurgical application. Sulfur content is undesirable, and gypsum has low thermal stability at metallurgical temperatures.

Key Characteristics

✔ High whiteness and brightness
✔ Smooth surface finish
✔ Controlled setting time
✔ Excellent mold and detail reproduction
✔ Low thermal conductivity
✔ Fire resistance due to crystallization water

Refining & Processing Properties

Mining & selection:
• High-purity rock gypsum or beneficiated gypsite
• Strict impurity control (clay, iron, silica)

Processing steps:
• Crushing
• Drying
• Grinding
• Calcination (120–180 °C)
• Classification
• Additive blending (retarders, accelerators)

Calcination Types

Available Forms

✔ Raw gypsum lumps
✔ Calcined plaster powder
✔ Quick-setting plaster
✔ Retarded plaster
✔ High-strength α-plaster
✔ Specialty molding plaster

Applications

Construction:
• Wall plastering
• Ceiling plaster
• Decorative cornices
• False ceilings

Decorative & casting:
• Statues and molds
• Architectural detailing
• Art and craft casting
• Ceramic molds

Industrial & medical:
• Dental plaster
• Medical casting
• Non-ferrous foundry molds

Advantages of Plaster Grade Gypsum

✔ Smooth, high-quality finish
✔ Fast setting and early strength
✔ Excellent mold accuracy
✔ Lightweight and fire-resistant
✔ Easy application
✔ Environmentally friendly

Why Choose Plaster Grade Gypsum?

Plaster-grade gypsum is essential for producing premium-quality plaster products. Its high purity ensures uniform whiteness, predictable strength, and compatibility with additives, making it the preferred raw material for builders, decorators, artists, and industrial mold manufacturers.

Plaster Grade vs Cement Grade Gypsum