6 ms·

I believe cans are more easily recyclable, in part because they're so easy to seperate from other trash (using a big magnet).

calebegg 8y ago
Most beverage cans are made from aluminum, which is not magnetic.
- ohithereyou 8y ago
  Aluminum is not ferromagnetic, but if you get it near a 3 Tesla magnet, trust me, you'll know.
- verytrivial 8y ago
  The material really just need to be conductive to feel the effect of A/C fields due to eddy currents as a Random Purveyor of such a device explains: http://www.walkermagnet.com/separation-eddy-current-separators.htm http://www.walkermagnet.com/separation-eddy-current-separato...
  - rexaliquid 8y ago
    Relevant SMBC: https://www.smbc-comics.com/comic/proof https://www.smbc-comics.com/comic/proof
  - cypherpunks01 8y ago
    Youtube "Magnapower Eddy Current Separator - Material Separation Tests": https://www.youtube.com/watch?v=QQ6ZC9MKNAw https://www.youtube.com/watch?v=QQ6ZC9MKNAw
newnewpdro 8y ago
I assume the main difference is the high temperatures used to melt metals like aluminum back down to ingots will either burn off all the contaminants or bring their remains to the surface to be easily removed like skimming dross. Plastics recycling is a much more delicate process, requiring all sorts of washing steps and finely controlled relatively low temperatures.
akiselev 8y ago
Aluminum isn't ferromagnetic so magnets don't work with it and stripping the graphics off a soda can alone requires just as much energy and nasty chemicals as other recycled materials. That's before you even smelt anything, which usually requires a forge that spends insane amounts of energy just to keep it from shutting down and needing an even more expensive cold start. It's not that recycling aluminum is easier than other materials, it's that making aluminum from raw bauxite is like the above process times ten. The chemicals are even more dangerous, the process management (environmental protection, regulatory compliance, etc) more expensive, and it requires even more energy. As a result, between 1/3 to 2/3 of all aluminum sold in the US comes from recycled materials because of economic reasons.
- munk-a 8y ago
  Your mention of advertising... I'd be really happy if we could start cutting down the insane effort we're putting into dyeing things and just relegate flashy marketing to the waste bin of history. The same with form advertising (clam shells and the like) where additional material is added just to make a product look more attractive.
  - lozenge 8y ago
    The clam shells make shoplifting difficult, and you need to get the barcode onto the can at a minimum, at which point what difference does the rest of the label make?
- kretor 8y ago
  https://en.wikipedia.org/wiki/Eddy_current_separator https://en.wikipedia.org/wiki/Eddy_current_separator
- michelledepeil 8y ago
  I was likely wrong wrt my argumentation. However, Eddy currents (TIL) make seperation _fairly_ easy if you have the right equipment, and comment https://news.ycombinator.com/item?id=18702317 https://news.ycombinator.com/item?id=18702317 seems to think "cleaning" and smelting are easier than in the plastic bottle case.

calebegg 8y ago

Most beverage cans are made from aluminum, which is not magnetic.

ohithereyou 8y ago
Aluminum is not ferromagnetic, but if you get it near a 3 Tesla magnet, trust me, you'll know.
verytrivial 8y ago
The material really just need to be conductive to feel the effect of A/C fields due to eddy currents as a Random Purveyor of such a device explains: http://www.walkermagnet.com/separation-eddy-current-separators.htm http://www.walkermagnet.com/separation-eddy-current-separato...
- rexaliquid 8y ago
  Relevant SMBC: https://www.smbc-comics.com/comic/proof https://www.smbc-comics.com/comic/proof
- cypherpunks01 8y ago
  Youtube "Magnapower Eddy Current Separator - Material Separation Tests": https://www.youtube.com/watch?v=QQ6ZC9MKNAw https://www.youtube.com/watch?v=QQ6ZC9MKNAw

newnewpdro 8y ago

I assume the main difference is the high temperatures used to melt metals like aluminum back down to ingots will either burn off all the contaminants or bring their remains to the surface to be easily removed like skimming dross. Plastics recycling is a much more delicate process, requiring all sorts of washing steps and finely controlled relatively low temperatures.

akiselev 8y ago

Aluminum isn't ferromagnetic so magnets don't work with it and stripping the graphics off a soda can alone requires just as much energy and nasty chemicals as other recycled materials. That's before you even smelt anything, which usually requires a forge that spends insane amounts of energy just to keep it from shutting down and needing an even more expensive cold start. It's not that recycling aluminum is easier than other materials, it's that making aluminum from raw bauxite is like the above process times ten. The chemicals are even more dangerous, the process management (environmental protection, regulatory compliance, etc) more expensive, and it requires even more energy. As a result, between 1/3 to 2/3 of all aluminum sold in the US comes from recycled materials because of economic reasons.

munk-a 8y ago
Your mention of advertising... I'd be really happy if we could start cutting down the insane effort we're putting into dyeing things and just relegate flashy marketing to the waste bin of history. The same with form advertising (clam shells and the like) where additional material is added just to make a product look more attractive.
- lozenge 8y ago
  The clam shells make shoplifting difficult, and you need to get the barcode onto the can at a minimum, at which point what difference does the rest of the label make?
kretor 8y ago
https://en.wikipedia.org/wiki/Eddy_current_separator https://en.wikipedia.org/wiki/Eddy_current_separator
michelledepeil 8y ago
I was likely wrong wrt my argumentation. However, Eddy currents (TIL) make seperation _fairly_ easy if you have the right equipment, and comment https://news.ycombinator.com/item?id=18702317 https://news.ycombinator.com/item?id=18702317 seems to think "cleaning" and smelting are easier than in the plastic bottle case.