Air classification of feed material is a means for separating particles by density, shape, and size. Developed during the 19th century for the cement industry, air classification enables higher capacity material processing. Air classifiers and other air classification systems have evolved with other material handling technology, the cement now extensively uses which, coal, food processing, pharmaceutical, powder coating, and other industries. Air classifiers can handle material separation challenges concerning energy use, fine particles, inconsistencies in particle size, maintenance, moisture, and product contamination, among other issues.
How Air Classifiers Resolve Material Separation Challenges
Air classifiers separate materials through directed airflow, resolving key material separation challenges for sectors from food processing to mining. Air classification also uses much less energy than other methods of material separation. Additionally, challenges to air classification include reducing contamination and product loss during material handling processes. Air classifiers also augment product consistency and enhance efficiency, largely negating fundamental material separation challenges like clogging commonly occurring with mechanical sieving. With adjustable parameters, air classification works well for bulk powders, lightweight recyclables, mineral processing, and other applications.
Applications for air classification include:
- Aiding composting processes for mixed municipal waste by separating out organic waste.
- Breaking up lighter demolition waste like pieces of wood and plastics and separating it from heavier construction materials like bricks, concrete and metallic substances.
- Classifying various types of plastics by size and weight in mixed recycling material.
- Corn fiber, fabrics, hemp, textiles and other fibrous materials.
- Disconnecting chaff and husks from grains.
- Dividing heavier and lighter glass fibers within recycling facilities.
- Handling dust and fine particulates.
- Isolating lightweight electronic components from heavier ones in e-waste recycling.
- Removing foam and other lightweight insulation materials from waste streams.
- Separating lightweight waste material from municipal solid waste like packaging, paper and plastic film.
The efficiency of air classification technology allows larger throughputs, while also providing more accurate and speedier sorting. Through precise material separation, air classifiers provide a cost-efficient solution for many material separation challenges while increasing quality.
How Air Classifiers Handle Common Material Separation Challenges
Air classification systems are used for conveying and material separation. The challenges posed by mechanical classifying methods make air classification better for many applications that require categorizing particles by density, shape, and size. Such methods are highly effective in industries where precise particle separation of materials directly affects operational efficiency and product quality.
Energy Use
With mechanical material separation, challenges arise over higher energy usage. Air classifiers reduce a system’s energy consumption, improving overall processing efficiency. By controlling airflow and utilizing gravity, air classifiers separate particles by density and size, requiring less energy than conventional mechanical separation methods. Grinding and other physical separation processes generally require much more force and, thus, energy. Additionally, mechanical separation tends to require more product reprocessing, which again requires more energy. With advanced automated designs, air classifiers offer even greater energy savings.
Material Separation Challenges of Fines
Ultrafine powders are notorious for clogging mechanical sieving devices used for material separation. Modern air classification techniques can largely overcome the challenges inherent in processing these exceedingly fine materials. Air classifiers separate coarser and finer particles via airflow, preventing blockages often caused by physically sorting materials.
Inconsistent Particle Sizes
Bulk feed material often varies markedly from batch to batch, leading to inconsistencies in the final product. Modern air classifiers make adjustments to airflow and other settings in real time, which helps ensure a more uniform particle size distribution.
Maintenance Challenges
Since air classification uses airflow and gravity rather than physical means of separation, fewer mechanical components are involved. This minimizes wear on moving parts, lowering the need for maintenance and corresponding costs. With fewer components, air classifiers are less prone to experience material handling challenges due to friction or other physical forces, resulting in lower maintenance expenditure.
Moisture
Moisture in materials often causes them to clump, making it much harder to mechanically achieve material separation. The challenges of moisture-laden materials make air classification preferable, as it can eliminate the need for an ancillary drying stage by using dry air. Classifiers using airflow rather than mechanical processes boost throughput and decrease energy expenses when working with wet materials.
Product Contamination
Contamination is a material separation challenge commonly occurring within mechanical systems. Physical contact with impurities increases the chance of contamination. Air classification is a cleaner process that doesn’t utilize direct contact, decreasing the chance of contamination. This is especially important for food or pharmaceutical processing sectors, where sanitation is key.
Prater Air Classifiers
Prater Industries makes air classifiers capable of producing narrow particle size distributions and separating ultrafine powdered bulk material. Our air classifiers can be used as standalone devices, though they’re also well-suited for integration into conventional milling systems. To learn more about resolving material separation challenges with air classification systems, contact the material handling experts at Prater.
