Processing plastic for recycling

In summary, processing plastic for recycling involves several key steps: collection, sorting, cleaning, shredding, and reprocessing. The process begins with gathering plastic waste, which is then sorted by type and color to ensure compatibility in recycling. After sorting, the plastics are cleaned to remove contaminants, followed by shredding into smaller pieces for easier handling. Finally, the shredded plastic is melted down and reformed into new products, closing the loop in the plastic lifecycle and reducing environmental impact. Efficient processing is essential to improve recycling rates and promote sustainable practices.
  • #1
d-Wizz
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TL;DR Summary
Advice for building specialised small-scale machinery to assist with recycling various plastic items.
[Mentor Note: link to OP's blog website deleted]

I need to learn where to find someone who will work with me to design and build machines for processing various plastic items. The end result will be granulated plastic, but the journey there will be different according to the physical and mechanical properties of the material being processed.

In summary, I am looking at building a small-scale agglomerator for plastic films. Research thus far seems to suggest that these machines are commonly used in China and India but nowhere else. The power consumption in the tens of kW may be one reason and the size and weight (1,000 kg) may be another. I want to investigate whether the concept is viable on a smaller scale such that domestic electricity (10A, 240V) can be used.

The basic concept is that a drum with blades on the bottom and on the sides rotates at very high speed. When plastic film is placed inside the drum, the friction generates sufficient heat to densify the plastic. The blades prevent the material from becoming one large lump. Apparently, at a certain stage, a cup of cold water is introduced into the drum. The plastic immediately solidifies and the blades chop it up. The result is said to resemble "plastic popcorn".
 
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  • #2
Welcome to PF.

I don't know much about the subject matter, but here is a link to a local startup company here in Silicon Valley that is bringing AI and more robotics to the field of Recycling. Maybe have a look at their website and contact them if it looks like there may be some synergy with your efforts. Good luck.

https://www.everestlabs.ai/
 
  • #3
d-Wizz said:
Research thus far seems to suggest that these machines are commonly used in China and India but nowhere else.
Erm... There is a reason for that.

Plenty of DIY-level 'recycling' methods gone viral on youtube and such (yes, many of them from India and China - kind of sad to see some done with 'western' machinery), but you should know that the reason they are banned to there is that hot plastic can very easily become really, really, seriously unhealthy.

Without having a solid knowledge about chemistry of plastics I recommend you to abandon this idea.
 
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  • #4
Rive said:
Without having a solid knowledge about chemistry of plastics I recommend you to abandon this idea.
I would be interested to receive your evidence for this being "banned" in Australia.

Would you therefore suggest an alternative method for densifying plastic film? I've been using a sandwich press for 4 years and it's tedious and very labour-intensive. Agglomeration seemed like a much faster and efficient method.

Fumes are not a problem with adequate ventilation or extraction system. That's the #1 reason I do not work with PVC.
 

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  • #5
d-Wizz said:
Would you therefore suggest an alternative method for densifying plastic film?
Nope.
By 'western' standards, this is just no to be done DIY.
Waste is for the (selective) waste bins.

d-Wizz said:
Fumes are not a problem with adequate ventilation or extraction system.
The place I live still about stoves for the winter.
Stoves has 'adequate ventilation'.
Still, when it's winter, the air quality is often terrible.
This is due two reasons.
- some financially less blessed people burns anything what can be acquired and can be burned
- stoves having ventilation, not filtering...

In short, emission is also a problem. Just ventilation is far from enough.

Regarding the attachment you (?) removed... There was two points you can/should seriously consider.
- the wastewater of washing is also a concern, and to properly address that it's best to have bigger plants for processing
- there was that line about the different melting point of different plastics, and the result of mixing them... At small scale you cannot expect consistent sorting.

Ps.: regarding that 'compacting'... Actually, before (DIY) compacting plastic waste is proper for sorting. After 'compacting' it's unknown waste -> landfill :confused: I really do hope I took that part about the sandwich press wrong...
 

FAQ: Processing plastic for recycling

What types of plastics can be recycled?

Most commonly, plastics labeled with recycling codes 1 (PETE) and 2 (HDPE) are widely accepted for recycling. Other types, such as 3 (PVC), 4 (LDPE), 5 (PP), and 6 (PS), may also be recyclable depending on local facilities. However, plastics labeled with 7 (other) are often not accepted due to their varied composition.

How is plastic processed for recycling?

The recycling process typically involves several steps: collection, sorting, cleaning, shredding, and melting. Collected plastics are sorted by type and color, cleaned to remove contaminants, shredded into small pieces, and then melted down to form pellets or sheets that can be used to create new products.

What are the challenges in recycling plastic?

Challenges in recycling plastic include contamination from food or other materials, the presence of mixed plastic types that are difficult to separate, and the economic viability of recycling processes. Additionally, some plastics degrade in quality during recycling, limiting their reuse potential.

What happens to plastic that cannot be recycled?

Plastics that cannot be recycled typically end up in landfills or are incinerated. Some may be downcycled into lower-quality products, while others may be processed into energy through waste-to-energy facilities. Efforts are ongoing to find more sustainable solutions for non-recyclable plastics.

How can individuals help improve plastic recycling efforts?

Individuals can help improve recycling efforts by properly sorting their recyclables, cleaning containers before recycling, reducing plastic use by opting for alternatives, and advocating for better recycling programs in their communities. Staying informed about local recycling guidelines is also crucial.

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