PET Mixed With PP/PE? Using A Sink Float Separation Tank

PET is one of the most widely recycled plastics, reused in products like packaging, strapping, and polyester fiber. However, rPET flakes are often mixed with PP/PE caps and PVC labels, reducing their resale value and making manual sorting impractical.

To address this challenge, EFFICIENT Machinery developed a sink float separation tank that efficiently separates and cleans PET flakes, improving recycling purity and plant efficiency.

Why is PET and PP/PE Separation So Difficult?

In the recycled plastics market, the purity and color of rPET, among other things, affect its reuse and economic value. Therefore, improving the purity of PET is crucial. First, we must understand the challenges we face in order to overcome them.

1. Similar appearance makes manual sorting difficult.

PET bottles closely resemble PP/PE caps and PVC labels in color and shape, making them difficult to distinguish accurately through manual or optical sorting. This is especially problematic in large-scale recycling lines due to low efficiency and high error rates.

2. The small difference in density requires precise separation equipment.

The density of PET is about 1.35 g/cm³, while the density of PP and PE is below 1.0 g/cm³. Although they can be separated by sink float separation tank in theory, the actual operation requires extremely high stability of the water flow, residence time, and disturbed flow control.

3. Label adhesive residue affects the separation process.

Residual adhesive and other residues change the buoyancy of the plastic debris, affecting sinking and leading to incomplete separation.

4. Cross-contamination reduces the quality of recycling.

Even a small amount of PP/PE mixed into PET bottle flakes can seriously affect the quality of recycled materials. This results in an uneven melting point and a decline in physical properties, meaning the recycled particles cannot meet food-grade or high-quality production standards.

5. The high cost of water and electricity

Using a traditional water tank is ineffective and consumes a lot of water and electricity. The separation and cleaning costs are high.

How to Accurately Separate? Sink Float Separation Tank

In response to the above problems, our professional team developed the latest sink float separation tank for PET recycling. It has the following features:

1. High automation eliminates the need for manual sorting.

• Equipped with a conveyor device that can fully automate the transfer and cleaning of PET bottle flakes, making the process efficient and convenient.
• Relying on the physical density difference, it can automatically complete the sorting of PET sinking and PP/PE floating without human intervention, making the sorting process more stable and labor-saving.

2. The precise control of the water flow system ensures fine separation.

• It adopts a constant water level design and a slow flow structure to prevent turbulence in the water from affecting the separation.
• The adjustable baffle and spiral pushing structure control the material residence time to improve separation efficiency.
• The system adapts to bottle flakes of different thicknesses and particle sizes, effectively separating light, floating impurities, such as PE/PP.

3. Effective cleaning removes stubborn stains.

• The sink float separation tank for PET bottle recycling is equipped with a spray cleaning device that rinses the bottle flakes a second time during the separation process and effectively peels off residual labels and adhesives.
• The output bottle flakes are more than 98% pure, greatly reducing the need for subsequent re-cleaning and re-sorting.
• The output PET bottle flakes guarantee to meet food-grade, fiber-grade, or high-end pelletizing material standards and increase the market price.

4. Simple structural design for easy maintenance and integration.

• The simple structural design makes it easy to maintain and integrate.
• The entire washing machine is made of stainless steel, which is corrosion-resistant and easy to clean.
• It can be flexibly configured in new or existing PET bottle recycling lines to achieve seamless integration and fast production.
• It supports customized capacity and conveying height to meet your needs.

5. Water recycling design, energy saving.

Our sink float plastic separation uses a water recycling and spraying design to effectively conserve water. The energy-saving design also helps avoid energy consumption.

Wide Use of Our PET flakes Washing Machine

Our plastic sink float separation tank is widely used in recycling lines for water bottles, post-consumer packaging, and industrial PET waste. It ensures high cleanliness and purity—perfect for producing food-grade rPET, polyester fiber, and plastic sheets.

How to improve value of rPET Flakes?

The key is cleaner, purer flakes. By adding a sink float separation tank, PET flake hot washing machine, and efficient drying systems, you can remove caps, labels, glue, and dirt, making your rPET flakes suitable for high-end applications and increasing their market price.

If you want to improve the purity and quality of your PET bottle recycling, please feel free to contact us!