In 2018, more than half of the waste in the EU was treated in recovery operations. Recycling, backfilling, and energy recovery saved this waste from going to a landfill. Sorting systems are a critical part of this process.
An effective sorting system increases the amount of waste that can be recovered, as well as the quality of the recovered materials. If your industrial management includes waste handling, you need the right sorting system to optimise your facility.
Learn about 6 sorting systems and how they can improve waste management in your plant.
1. Manual Picking Lines
Many waste sorting facilities that use an auto sorting system also incorporate manual picking lines. Manual sorting can occur at various stages of the sortation process. It’s especially useful for removing large, bulky items before mechanical sorting starts.
Hand picking typically occurs on a sorting belt or table. Manual separation is time-consuming and labour-intensive. It leads to a better overall separation of waste and higher recovery of recyclable materials, though.
2. Air Separation
Air classifiers, cones, or cyclones separate light material from heavier or denser material. Fans create a column of air moving upwards or a spiral airflow. The air blows lighter materials upwards while heavier materials fall.
The low-density materials enter a separator where they fall out of the air stream. Denser materials fall into a skip below the separator.
The effectiveness of air separation depends on the strength of the air stream. The way that materials enter the air currents is also important.
3. Magnetic Separation
Magnets can separate iron, steel, and other ferromagnetic materials from non-ferrous metals. Permanent magnets or electromagnets will generate the magnetic field.
Ferrous materials lift and stick to the magnetic band. After being removed, they drop off into a skip.
Magnetic separation is generally effective for ferrous materials. It won’t work on metals like stainless steel, copper, and aluminium, though.
4. Eddy Current Separator
An eddy current separator sorts conductive non-ferrous metals from other materials.
When a piece of non-ferrous metal passes over a magnetic rotor, eddy currents form in the metal and create a magnetic field. The polarity of this magnetic field is the same as the rotating magnet. This makes the magnet repel the metal.
The repulsion throws the non-ferrous metal away from the magnet. The metal separates from the original product stream. This automatic separation means an eddy current separator can handle high capacities.
Eddy current separators need an even flow of material to work most effectively. Getting a consistent layer of materials across the feeder or conveyor belt is especially important with smaller-sized items.
5. Trommel Screener
Trommel screens classify sizes of solid waste. A trommel screen is also called a rotary screen or drum screen. It’s a large rotary drum with a grate-like surface.
The drum is usually elevated at an angle at the feed end. Large end openings help separate very coarse material from finer material.
When the feed material goes down the rotating drum, material smaller than the screen passes through. Larger material goes out through the other end of the drum.
Lifter bars help objects lift and then drop to move further down the drum. Lifter bars aren’t an option for heavy items, though.
Trommel screening improves the quality of the solid waste. It removes inorganic material from the air-separated lighter items.
6. Density Separators
A density separator or concentrating table screens material based on one of three particle characteristics:
When operators control two of these characteristics within certain limits, a density separator will accurately sort a complex mixture. It can sort into a continuous gradation based on the range of differentiating characteristics.
Types of sortation include from light to heavy, or fine to coarse. Isolating many intermediate gradations is possible.
Material feeds onto the narrow side of a flat, porous deck. The deck vibrates while air blows upward through it. The air fluidizes the material and makes it separate into layers.
Once the material is arranged in layers, the density separator can easily divide it. Each fraction goes to a separate discharge spout.
Preparation for Sortation
Preparing material for sorting makes recycling sorting systems more efficient. Bag openers open the bags containing waste material and empty them for subsequent treatment.
Size reduction improves handling characteristics and makes waste easier to dispose of. Equipment like mills and shredders reduces the particle size of incoming materials.
Bag openers ensure you have a constant supply of material in the sorting system. Quality bag openers will open and empty the bags without cutting or damaging the items inside. They eliminate the need for manual bag openers.
A hammer mill is a rotating set of steel hammers. As waste passes through them, the force pulverises it into small pieces.
In a vertical hammer mill, the clearance between the hammer tips and the enclosure is adjustable. This determines the size of the final particles. A horizontal hammer mill has a grate that can be changed to create particles of different sizes.
Shredders reduce waste of different shapes and sizes into smaller, more uniform particles. They can process many types of material, including plastic, metal, e-waste, wood, and tyres.
Finding the Best Sorting Systems
Several different sorting systems are available to make your waste management more efficient. Sorting lines that incorporate several sorting systems are often the most effective. Preparation for sortation is also important to achieve the best results.
ANIS has been designing, manufacturing, and selling a wide range of waste processing conveyors for more than 25 years. Our sorting systems are an integrated solution for separating mixed material flows by type. We configure our systems to suit your project.
Contact us today to discuss how our equipment can meet your waste sorting and processing needs.