The PET bottle recycling and washing production line plays a crucial role in processing the recycling and reuse of discarded PET plastic bottles, such as mineral water bottles, beverage bottles, and cola bottles. As global awareness of sustainability rises, the efficient recycling of PET plastics has become essential in reducing plastic waste, conserving resources, and promoting the circular economy.
This article explores the key components and processes involved in PET bottle recycling, emphasizing the production of high-quality PET bottle flakes for downstream applications such as wire drawing, injection molding, and blistering.
The PET bottle recycling and washing process is divided into several critical stages, including:
1.Label Removal and Crushing
2.Cold Water Washing
3.High-temperature Hot Water Cleaning
4.Separation of Caps and Flakes
5.Friction Cleaning
6.Dehydration and Drying
These steps ensure that the final product—clean and pure PET bottle flakes—can be used for various industrial applications, contributing to sustainable materials reuse.
1. Initial Sorting and Label Removal
The process begins after the discarded PET bottles are collected and packaged. One of the first steps is to break the bales using a bag opener, which loosens the tightly packed bottles. Most of these bottles come with sleeve labels, particularly those used for beverages. These labels need to be removed efficiently.
A label removal machine is used to strip off the labels, separating them from the PET bottle body. This step is crucial because the presence of labels, especially made of different materials like PVC, can contaminate the final product. Label removal can take place before or after color sorting, depending on the efficiency of the system.
2. Color Sorting
Color sorting is essential because PET bottles come in different colors (clear, green, blue, etc.), and each color has different applications in the recycling process. Clear PET is the most valuable, as it can be easily dyed and repurposed. The bottles are separated based on their color using optical sorting machines or manual sorting techniques to ensure that the final flakes are uniform in color.
3. Crushing
Once the bottles have been sorted and labels removed, they are fed into a crusher, where the bottles are broken down into smaller pieces. These pieces, referred to as bottle flakes, are typically reduced to a size of around Ø10-Ø16 mm, which allows for easier handling and further processing.
4. Separation of Bottle Caps and Flakes
After the crushing process, the bottle caps, usually made from PP (Polypropylene) plastic, need to be separated from the PET flakes. This is accomplished using a sink-float separation system. PET flakes are denser and sink in water, whereas PP caps are less dense and float, making separation relatively straightforward.
5. High-temperature Hot Water Washing
Once separated, the PET flakes undergo high-temperature washing. This step involves cooking the flakes in a high-temperature caustic soda solution or detergent, which helps remove stubborn contaminants such as oil, adhesives, and organic residues. The use of caustic soda is particularly effective at breaking down hydrophobic dirt and ensuring the cleanliness of the flakes.
6. Friction Cleaning
Following the hot water wash, the PET flakes are subjected to friction cleaning, where rotating blades create high levels of agitation. This friction removes any residual dirt, adhesives, or foreign particles that remain attached to the flakes. Friction washing is a key step in ensuring that the PET flakes meet high-quality standards for downstream processing.
7. Cold Water Rinse
After friction cleaning, the flakes are rinsed in cold water to remove any remaining caustic soda, detergent, or impurities. This step ensures that the PET flakes are not only clean but also neutralized from any harsh chemicals that were used in previous cleaning stages.
8. Dehydration and Drying
The final stage in the washing process is dehydration and drying. The cleaned PET flakes are passed through a centrifuge or a dryer to remove excess moisture. Drying is crucial, especially for applications such as filament-grade PET, where moisture content needs to be minimized to ensure product quality.
Many recycling companies face the issue of low whiteness and glossiness after the cleaning of PET bottle flakes, especially in lower-quality recycling systems. The appearance of the flakes can significantly affect their value in downstream applications.
To improve the whiteness of PET flakes, many companies use chemical additives. Suractent716G powdered dispersant, a modified acrylic polymer, has proven to be highly effective. It enhances the whiteness and gloss of the cleaned PET flakes by preventing redeposition of dirt and reducing contaminants such as calcium and magnesium ions in high-temperature washing conditions.
This dispersant ensures a better final product by improving the surface quality of the flakes, making them more suitable for high-grade applications like filament production and bottle-to-bottle recycling.
Once the PET bottle flakes are thoroughly cleaned and processed, they can be used in a variety of applications:
Wire Drawing: Clean PET flakes can be melted and drawn into fine fibers for textile applications.
Injection Molding: PET flakes can be used to manufacture a variety of plastic products through injection molding processes.
Blistering: PET flakes are often utilized in the production of blister packaging, which is commonly used in the packaging of small consumer goods, foods, and pharmaceuticals.
These applications highlight the importance of ensuring high-quality recycling processes to maximize the reuse potential of PET plastics.
The PET bottle recycling and washing production line is a critical component of the global effort to reduce plastic waste and promote the reuse of materials. By understanding the detailed processes involved, such as label removal, hot washing, and friction cleaning, we can appreciate the technical expertise required to produce high-quality PET flakes for industrial use.
The addition of Suractent716G dispersant in the washing process helps resolve common issues like low whiteness and glossiness, further enhancing the quality of recycled PET. As industries strive to adopt more sustainable practices, the role of advanced PET recycling technology will only continue to grow.
RETECH is a creative company focusing on the technology R&D of Plastic recycling machinery solutions.
