Waste sorting has evolved from a labor-intensive manual task into an automated process driven by high-tech equipment, making it crucial for resource utilization.
I. Why is precise sorting essential?
To effectively recycle resources, we must first accurately separate mixed waste based on various materials, properties, and values. Precise sorting can:
1. Enhance the quality of recyclable materials, including plastics, metals, and paper.
2. Minimize the burden of end-of-life treatment by effectively separating combustibles and organic materials, thereby enhancing the efficiency of incineration power generation or increasing the gas production rate of anaerobic digestion.
3. Minimize environmental pollution by preventing harmful substances, such as batteries and mercury-containing lamps, from entering the ecosystem.
II.Waste Sorting Equipment Sorting Technology Principles
Waste Sorting Equipment
Waste sorting equipment mainly includes the following categories:
1. Bag Opener and Material Plate Feeder Conveyor
When waste arrives at the plant, it is typically packed in plastic bags. The process begins with a bag-breaking machine that tears and breaks open the bags, allowing the waste to be loosened and exposed for easier sorting. Following this, a feeder distributes the waste evenly and at a consistent thickness on the sorting belt. This prevents any accumulation of materials and ensures efficient sorting.
2. Shredder:
The shredder machine pre-processes waste materials.
3. Screening Equipment
Mainly used for grading by size.
Trommel Screen: Like a slowly rotating, large mesh cylinder, screens with different apertures can separate waste into coarse, medium, and fine grades, effectively separating organic matter, broken glass, sand, and other fine particles.
4. Magnetic Separation
Magnetic separators use a strong magnetic field generated by permanent magnets or electromagnets to efficiently remove ferrous metals—such as aluminum cans and sheet metal—that are mixed in with waste. This method is one of the oldest and most effective sorting technologies available.
5. Air Separation Equipment
Air separators operate on aerodynamic principles, utilizing controlled airflow to separate lightweight, bulky materials such as plastic films and paper from heavier materials like bottles, cans, and bricks. This process is essential for achieving effective dry-wet separation as well as light-heavy separation.
6. Optical Sorting Equipment – The Core of Intelligent Sorting
This technology represents the leading edge of current advancements, equipping machines with both visual recognition and decision-making capabilities.
Near-Infrared (NIR) Spectroscopy Technology: Every material has a unique absorption and reflection spectrum for near-infrared light, similar to human fingerprints. Sensors scan these materials to instantly identify different types of plastics, such as PET, HDPE, and PP, as well as paper and wood. Precise airflow nozzles are then used to direct these materials into the appropriate collection tanks.
Visible Light Recognition Technology: This method employs high-resolution cameras to sort materials based on visual characteristics such as color and shape. For example, it can separate transparent bottles from colored ones or identify specific types of packaging.
Artificial Intelligence (AI) and Deep Learning: The latest optical sorting equipment incorporates AI technology. Through extensive data training, these machines can not only identify various materials but also differentiate the shapes of items (like bottles, caps, and films) and filter out label interference. This leads to a significant improvement in sorting accuracy and adaptability.
7. Waste Baler Machine
The processed waste is baled by a baler for transportation and recycling.
III. Systematization and Intelligence in Waste Sorting Equipment Technology
The future of waste sorting technology is advancing towards greater integration and intelligence:
1. Digital Twin: This involves creating a virtual model of the sorting line, allowing for real-time monitoring, fault prediction, and process optimization.
2. Robotic Sorting: For stages that require precise selection after optical sorting, robotic arms equipped with AI vision can replicate human grasping techniques, making them suitable for sorting complex items.
3. Intelligent Control Throughout the Process: Utilizing sensor networks and a central control system, each sorting unit can work together intelligently, automatically adjusting operating parameters based on changes in the composition of incoming materials to maximize overall sorting efficiency.