Recycling beverage cartons isn’t 100% efficient. The process yields some unusable garbage as a byproduct. Why? Because containers like juice boxes are mostly paper, but also contain plastic and aluminum. The recycling process recovers the paper fibers for re-use, but what’s left after that is a mixture of plastic rejects and other bits that aren’t good for anything other than an incinerator or a landfill. Until now, anyway!
It turns out it is in fact possible to turn such reject material into a product that can be injection-molded, as shown here with [Stefan Lugtigheid]’s SAM bird feeder design. The feeder is not just made from 100% recycled materials, it’s made from the garbage of the recycling process — material that would otherwise be considered worthless. Even better, the feeder design has only the one piece. The two halves are identical, which reduces part count and simplifies assembly.
[Stefan] makes it clear that the process isn’t without its quirks. Just because it can be injection-molded doesn’t mean it works or acts the same as regular plastic. Nevertheless, the SAM birdfeeder demonstrates that it can definitely be put to practical use. We’ve seen creative reprocessing of PET bottles and sheet stock made from 3D printed trash, but recycling the garbage that comes from recycling drink cartons is some next-level stuff, for sure.
But how much energy is required to recycle the material? And how many hazardous chemicals does the material leach after recycling? Those are the big problems with recycling many plastics. It takes massive amounts of energy (creating more polution than just burning it in a good incinerator) and/or it leaches toxic materials into whatever touches it.
Just because you CAN recycle something doesn’t always mean you should.
Well being food packaging I’d expect all the plastics in use have to be food-safe. So Leeching anything nasty would be very surprising to me as long as all you are using is left over juice cartons there should be no chemical surprises either
As for energy use creating new plastics is always going to be higher energy cost than recycling, – The heating and moulding energy costs are going to be basically the same. But the extraction then refining via cracking and distillation to get the plastics you want don’t need to be repeated when recycling.
The inks on the outside of that carton, may not be *as* food safe as the foil lining inside.
My thought is, that’s great, but does this material have any other use than just ‘stuff’? If it’s got some material properties which are actually useful then great, but most of these ‘recycling’ ideas I see, create one or two items, mostly of things you’d only ever want one or two of at which point the recycling process is now a waste unless you’re going to hand them out to all and sundry…
A good point on the inks, though again meaningfully toxic for something humans are expected to handle would be a surprise. As for usefulness for anything but ‘Stuff’ well with the shapes the bird feeder has taken I’d be shocked if all the plastic protective cases on everything on our desks could not be made with this material.
Might need a rejig in the tooling shapes some of the smallest items might need to bulk up to account for the material properties and this type of plastic not working like more usual injection plastics. But it can be made to work or those bird feeders would not exist.
So what we want to see is a source of material like this being used to make something useful, being a source i’d expect to be perfectly food safe lunchboxes, and icecream carton spring to mind as a great use for it.
As for energy use creating new plastics is always going to be higher energy cost than recycling, –
That’s a pretty bold statement, and highly doubtful. The cost to recycle is huge, especially for mixed plastics that require a lot of manual labour and energy input for collection, sorting and reprocessing. The resulting mongrel product is of low value compared to virgin plastic.
For example, HuffPost quotes a study in 2013 that found recycling a ton of plastic bags costs $4000, and the product sells for $32.
It’s not like you can toss your empty Fuji water bottle into the blue box, and expect it to be sorted, ground up, and re-extruded into a new Pepsi bottle next week, thinking you’ve saved the oil required to make virgin plastic. No, that recycled waste is of lower value, and goes into something that doesn’t require pristine, high-quality material with well-defined processing characteristics.
So the end-user price of recycled plastic must be less than virgin material, or there’s no market for it. In order for the middleman recycling processor to survive, their feedstock must be cheap (or negative cost), their labour must be cheap, their logistics (collection, sorting, storage, and final product delivery) must be cheap, and the energy required to do the processing must be minimal.
It’s impossible to believe that recycling of a general heterogeneous “recycleable” waste stream can possibly compete economically with virgin material, unless that reprocessing is heavily subsidized by collection fees and/or some kind of user fee or tax on the parent product.
Of course there are exceptions, when the material is energetically expensive to make (e.g. aluminum, glass, sometimes cement/concrete) or logistics of collection or alternate disposal favour recycling (e.g. lead, asphalt), or the waste product is relatively cheap to sort and reprocess, and there’s a market for the end product (iron,steel).
I don’t disagree on the quality of virgin plastic vs mongrel recycled. So its not a true like for like comparison. But as so many things like bird feeders, cases for our single board computers’s, monitor cases the list is almost endless do not require the quality of virgin plastics it is a valid in the real world comparison. So yes the quality isn’t likely to be the same, the energy cost of recycling it is much lower. So where the purity and quality is not a concern as in these bird feeders we should be encouraging it. Saving all that precious virgin plastic for things that have to be that way!
And the economics are a separate issue entirely. Not viable on that score is for the people doing this type of recycling to figure out.
Economics never had interest in health, earth, flora or fauna, including humans. There is an end to the sources we use and need. Period.
In the end, nature’s waste generates and regenerates itself, while this idea saves a little consumption. It’s a tough standard, but it’s the standard.
I’ve mentioned in HaD comments before of a company in Manchester, England, England, across the Atlantic Sea
That started recycling plastic/alumin[i]um packaging in 2017 by microwaving the packages to melt the aluminum and plastic to separate them.
Hairy reference, dude.
Why in the FSM’s name would they bother using high-grade heat like microwaves to melt stuff? If the objective is just to get the waste hot, why bother burning fuel to inefficiently make electricity (and waste 60% of the heat) to excite a magnetron (and waste even more heat) to ultimately heat the waste?
That’s a almost as kooky as that “clean coal” notion a few years ago to process coal with microwaves before burning it in a power plant.
I’m not sure if the news article I saw on TV, said one of the plastic by-products was used to supply heat/energy for the process, maybe microwaves just initiated the process. (sort of like wood gas used to make charcoal).
Thanks for catching my reference, dude!
B^)
Back when we wore onions in our belts…it was the style at the time.
I remember taking bottles back to get a deposit returned. I remember paper bags. There’s a whole lot that industry “improved upon” which takes more energy to properly dispose of the items. Canned goods use paper and recyclable metals.
Can’t we just re-invent the old ideas to make them better, rather than poison the environment with microbeads of plastic for EVERYTHING??
I think if you want to tackle environmental issues Governments need to impress upon industry that packaging needs to be either 100% recyclable (with standards set so the energy to recycle is viable and preferably uses waste heat from energy generation) or 100% biodegradable. We’re inventing new things that improve upon the old without any forethought to if we SHOULD improve upon what we already have.
I think that if the cost of recycling is mainly energy it is still a way to go, as we can always use renewables; extract the materials from the earth is far harder and destroying.
not sure if it’s a win but for a metal/organic mix, the differential heating may be desirable for separation. as i understand it, microwaves heat metal much more effectively than they heat plastics. though there are probably a bunch of geometric considerations i’m ignorant of.
microwaves heat metal much more effectively than they heat plastics.
Maybe counter-intuitive to some, but that’s generally not true. If true, why would microwave oven walls be made of metal?
Metals, being good conductors, tend to either reflect the RF energy, or act like antennas and concentrate high voltage at the edges — the cause of arcing in many cases. If that metal edge is in close proximity to a lossy dielectric (plastic, water, human tissue…), then the RF heating at that location will be increased. A mixture of metal filaments in plastic could have an effect effect to a susceptor: cause enhanced microwave absorption in that region.
It’s tough to predict the behaviour of random scrap mixtures of metal in plastic though — you would never want to depend on it in a materials processing pipeline.
https://www.instructables.com/id/Simple-Organizer-of-Tetrapack-Storage/