Sorting shredded PP (polypropylene) and PE (polyethylene) plastics can present some challenges that can affect the efficiency and quality of the sorting. Because the densities and colors of PP and PE plastics can be very similar, making traditional physical sorting methods such as density sorting or color sorting more difficult. This can make it difficult for sorting equipment to accurately identify the difference between the two.
Near infrared optical sorter to separate PP from PE
Using near-infrared (NIR) optical sorting technology(polymer sorter) to separate PP (Polypropylene) from PE (Polyethylene) is a common approach in the recycling industry. Near-infrared spectroscopy can be employed to detect the unique spectral characteristics of different plastics and differentiate between them. Here’s how the process generally works:
- Spectral Analysis: Near-infrared light is directed at the plastic waste material. Different plastics have distinct absorption and reflection patterns in the near-infrared spectrum due to variations in their chemical composition. PP and PE, being different types of polymers, will exhibit different spectral signatures.
- Sensor Detection: A sensor detects the reflected or transmitted NIR light from the plastic waste. This sensor captures the unique spectral pattern of each plastic type.
- Data Analysis and Classification: The collected spectral data is then analyzed by a computer system using specialized software. Machine learning algorithms are often employed to classify the plastics based on their spectral patterns. The system has been trained on a dataset of known PP and PE spectra, allowing it to accurately differentiate between them.
- Sorting Mechanism: Once the plastic type is identified, the sorting system activates a mechanism to physically separate the PP from the PE. This could involve using air jets to blow the plastic pieces into separate containers or diverting them onto different conveyor belts.
- Efficiency and Adjustment: NIR sorting systems can be optimized and calibrated to achieve high accuracy in distinguishing between different plastics. However, adjustments may be needed over time due to changes in the composition of the plastics being sorted or variations in the recycling process.
We have polymer sorter I pro series which could sort the PP and PE effectively.The sorting accuracy is above 99% with high production capacity.It can be sorted at the same time according to color and material, including sorting of the same color but different materials, which can effectively reduce equipment operation costs and improve sorting efficiency and production capacity.By identifying and removing other materials and variegated flakes, sorted PE and PP sheets can achieve unprecedented levels of purity, meeting both current regulatory requirements and end-customer needs.
