Products Description
Bulk waste sorting process
I. What is Bulk Waste?
Bulk waste refers to discarded items from daily life that weigh more than 5 kg, have a volume greater than 0.2 cubic meters, or exceed a length of 1 meter. These items are typically structurally sound and may require disassembly for disposal.
The main categories of bulk waste include:
1. Used furniture: Items such as bed frames, wardrobes, sofas, tables, and chairs.
2. Used household appliances: This category includes refrigerators, washing machines, televisions, and air conditioners.
3. Other bulky items: These can consist of kitchenware, bathroom fixtures, and construction waste, including doors and windows.
Characteristics analysis:
Large volume and low density: These items take up significant storage and transportation space, leading to higher transportation costs.
Complex composition and uneven value: Typically made up of various materials such as metal, wood, plastic, sponge, textiles, and glass, which results in considerable variations in recycling value.
High processing difficulty: Their sturdy structure necessitates crushing and dismantling before effective sorting can occur.
Environmental and safety risks: Improper handling of substances like Freon, lubricating oil, and fluorescent powder in discarded appliances can lead to environmental pollution. Additionally, metal components, such as springs in sofas, can create sparks during crushing, posing safety hazards.
Bulk waste sorting is essential.
II. Bulk waste sorting process:
bulky waste sorting process
The bulk waste sorting process typically consists of the following steps:
1. Pre-treatment: Once bulky waste arrives at the disposal center, it is first weighed and registered. Next, it is manually sorted to separate clearly recyclable items (such as still-usable old furniture) from hazardous waste (like batteries and paint cans).
2. Coarse Crushing and Shredding: The bulk waste is fed evenly into a specialized crusher, such as a twin-shaft shear crusher, via a chain conveyor. This equipment uses two opposing rotating cutter shafts to crush large objects, such as sofas and mattresses, into relatively uniform fragments (typically measuring 10-30 cm) through a process of shearing, tearing, and compression.
3. Magnetic Separation: The crushed material is then processed through a suspended self-unloading magnetic separator or magnetic drum. The strong magnetic force efficiently attracts ferromagnetic metals, primarily steel, from the mixture, allowing for initial metal resource recovery. This stage is one of the most valuable and technologically advanced in the sorting process.
4. Air Separation: An air separator utilizes aerodynamic principles to separate the crushed mixture into lighter and heavier components. Controlled airflow carries away lighter materials, such as fabrics, sponges, plastic films, and dust (collectively referred to as “light materials”), while heavier items, including wood, hard plastics, and rubber, remain in place (known as “heavy materials”).
5. Screening: The heavy materials sorted through the air separator are passed through a drum screen or vibrating screen for grading by size. Smaller fragments, such as soil, small stones, and glass shards, are screened out and can be used as fuel or disposed of in landfills. Materials of the appropriate size continue to the next sorting stage. This step effectively removes impurities and enhances the purity of the subsequent sorting process.
6. Intelligent Sorting
To effectively recycle higher-value materials such as non-ferrous metals and specific plastics, modern sorting lines utilize advanced sorting technology:
a. Eddy Current Separator: This device is used to separate non-ferrous metals like aluminum and copper. It operates by using a high-speed rotating magnetic roller that generates an alternating magnetic field. This field induces eddy currents in the non-ferrous metals, which then create a magnetic field that opposes the original one. As a result, a strong repulsive force is generated on the metal particles, ejecting them from the mixture.
b. Near-Infrared (NIR) Spectroscopic Separator: This is currently the most advanced technology for sorting plastics. The equipment emits near-infrared light to illuminate the material. Different types of plastics, such as PET, PP, and ABS, reflect distinct spectral fingerprints. When the sensors detect these spectral patterns, the corresponding type of plastic is blown away using precision airflow nozzles, resulting in high-purity and efficient sorting for recycling.
7. End-of-pipe treatment and resource utilization
The sorted pure materials are packaged(waste baler machine) separately and sent to downstream enterprises for resource utilization:
Metals: These are transported to steel mills or non-ferrous metal smelters for remelting.
Wood: After being crushed, wood can be converted into biomass fuel (RDF/SRF) or engineered wood products.
Plastics: Once washed and granulated, plastics are used as raw material for producing recycled plastics.
Lightweight materials (such as fabrics and sponges): These materials are typically used as raw materials for solid-derived fuel (RDF) in cement plants and other applications as a substitute for coal.