Also interested if there is any recent work on micro reclamation of discarded high value materials. Probably drinking too much sci Fi cool aid but seems like landfills may someday be a treasure for mining once the tech is capable
The most valuable stuff in a landfill is probably aluminum, and based on some 2018 US numbers [1] estimated 1.8% of the mass of the landfill. Would need to dig through ~55.5 tonnes in an ideal scenario to get a tonne. Assuming you can sort it on site you still need to transport it to a facility. Process it and melt it back down into a usable form before selling it. Oh and there are various alloys that you probably have to figure out sorting between as well. At around $2200 / tonne right now. I just don't see the economics working out.
Perhaps in an older landfill it could be denser, and maybe it could be easier to sort after other materials have started to break down. Still doubt it would be very economical yet. But I wouldn't be surprised if it becomes economical someday.
I do wonder if it may be possible to sort more of the aluminum out on its way in to the landfill rather than trying to do it after the fact. It was something like $6B worth of aluminum landfilled based on the 2018 numbers.
I was also curious about separating efficiently and went down a rabbit hole on Eddy Current Separators. High speed rotating alternating magnets I guess can influence non-ferrous materials like aluminum. [2]
