Dry blending and compaction granulation processes utilize specialized equipment to create uniform granules from powdery materials. Below are the commonly used granulators for dry blending and compaction in industrial settings, along with their functions and advantages.
Roller Compactors (Chilsonators)
Roller compaction is one of the most widely used methods for dry granulation. Roller compactors, also known as Chilsonators, apply mechanical pressure to powders, compacting them into ribbons or flakes. These ribbons are then broken down into granules.
Key Features
- Compaction Process Powdered material is fed between two counter-rotating rollers. The force exerted by the rollers compacts the material into sheets or ribbons.
- Granulation The compacted ribbons are broken down into granules through a mill or crusher.
- Particle Size Control The granule size can be adjusted by altering the pressure on the rollers, the gap between rollers, and the milling parameters.
Applications
Ideal for heat and moisture-sensitive materials since no liquids or heat are required in the process. Commonly used in the pharmaceutical, chemical, and polymer industries to granulate materials like Sodium Benzoate and antioxidants.
Advantages
- Moisture-free process No need for binders or drying, making it suitable for sensitive materials.
- Continuous Operation Suitable for large-scale production.
- Particle Size Uniformity Enables control over particle size and density.
Oscillating Granulators
Oscillating granulators are often used in combination with roller compactors or slugging equipment to break down compacted sheets or slugs into granules. While they are not exclusively used for dry compaction, they play a crucial role in achieving the final granule size.
Key Features
- Breaking Down Oscillating granulators consist of a rotor that pushes compacted material through a screen to form granules.
- Screening Various screens can be used to control the final granule size.
- Gentle Granulation Oscillating granulators exert less force, producing more uniform granules without causing excess heat or particle degradation.
Applications
Used in pharmaceutical, chemical, and food industries.
Suitable for delicate materials that require a gentle granulation process.
Advantages
Adjustable Granule Size The size of the granules can be controlled by changing the screen size.
Versatile Can be used for both dry and wet granulation processes.
Screw Feed Granulators (for Continuous Dry Granulation)
Screw feed granulators are often used in continuous granulation processes, where powders are fed into the granulation chamber using a screw conveyor. This is an efficient method for continuous compaction and granulation.
Key Features
- Screw Feed Mechanism Powders are fed continuously into the granulation chamber via a screw conveyor.
- Compaction The material is compressed using rollers or compactors as it moves through the screw mechanism.
- Continuous Granulation Ideal for large-scale production where continuous operation is necessary.
Applications
- Used in the polymer industry for stabilizing additives, such as Sodium Benzoate and antioxidants.
- Often used for granulating thermosensitive materials that should not be exposed to high temperatures.
Advantages
- Continuous Process Suitable for large-scale industrial applications with high throughput requirements.
- Uniform Granule Size Provides consistent granule size control through the screw and compacting mechanism.
Considerations for Choosing a Granulator
Material Sensitivity Some materials, like antioxidants, can be sensitive to heat and moisture, which makes dry granulation (roller compaction) ideal.
Scale of Production Continuous processes like roller compaction and screw feed granulators are ideal for large-scale operations, whereas slugging may be suitable for small batch production.
Desired Granule Size Oscillating granulators or additional milling stages may be needed to achieve specific granule sizes.
Final Application The choice of granulator should align with the final product requirements, such as stability, handling properties, and particle size distribution.
By selecting the appropriate granulator, companies can ensure efficient, consistent, and high-quality granules for their formulations, whether they are handling Sodium Benzoate, Antioxidant 1010, Antioxidant 168, or other sensitive materials.