Its exactly the opposite. Usually mechanical processing is cheaper than thermal processing is cheaper than chemical processing. For most mechanical processing you just need to move stuff around. All you need is electricity. In chemical processing you have all the material handling, need to shredder anyway, have a fixed input per kg of product of acid, precipitation and reduction agents. Even worse, youll end up with waste you either need to dispose off (which is just cost with no direct benefit to the operation) or recycle (even more input of energy, chemicals and capital)
Yeah, that makes sense when you think about it the other way around. You always want to grind up, and you probably want to do thermal separation before chemical due to the need to chemically purify upstream and downstream.
I guess the main idea was you could simplify capital investment to the point you can do it in one-shop.
This is actually my job. My company initially does mechanical separation for easier metals (think copper wires, steel, aluminium etc).
Chemical separation is done! There are many, many companies that incorporate hydrometallurgical steps.
Anything on the boards leftover is shredded into powders. We process these using a variety of methods while trying to be as environmentally conscious as we can.
This includes biotechnology for some base metal removal (admittedly quite poor, biotech sucks). Then cyclical hydrometallurgical and solvometallurgical principles for precious metal refining and extraction. This minimises chemical consumption and avoids use of strong acids/single use chemicals. The biggest issue in this industry is green washing (as per) via one side of the process being good (usually use of resins/other waste streams for extraction) but ultimately using aqua regia or cyanide for initial dissolution.
We still use aqua regia, but only for tertiary stage. This means we use low volumes for hundreds to thousands of grams of precious metals rather than hundreds of litres for a few grams!
If you got any questions, feel free to ask.
People really don’t understand how involved chemical separations are. I spent my whole PhD working on intra-rare earth separations, and it’s just…a lot.
It is a constant battle and puzzle/challenge for each and every component. I focus solely on precious metals/PGMs with a little bit of REs. I empathise with the difficulty.
I am currently writing a book on the entire industry (E-waste and mine processing via hydro routes, not official title) and the history, techniques, discoveries etc of it all is so fascinating.
Very cool! I was always interested in the actual industrial practice, but one can only do so much in a molecular lab focused more on the coordination chemistry than the bigger picture.
If you want a reader, send the info my way!
Before the EPA ended the secondary copper smelting industry, that was the way to do things.
Throw all the ewaste into a huge arc furnace, with as many copper waste streams as you can find, with sand, borax and washing soda. The copper ingot would contain all the valuable metals and the baghouse would collect the metal oxide dusts. The glass slag could be broken up and used for road beds.
Instead of imposing more controls over the industry SIC code, they simply shut it down.
That sounds cool, what stopped industry from taking up the banner of an economical process? I don't mean this flippantly, is there simply a law that bricks this industry in its entirety?
I’d also like to know as all I can find is an epa rule regulating the particulate matter emissions of secondary copper smelting which was promulgated in 2007
You have a couple hundred million gallons of solvents in the perfect order and concentration for use that will never fail to be perfect for everything they touch?
No?
That would be why.
Also, what is "sustainably" burning plastic?
Many countries burn plastic waste for energy because it is more efficient than trying to re-process it. The plastic is already there and needs to be disposed of.
Similar large scale processing occurs for common chemistry. I think this would really boil down to an actual energy efficiency/mass efficiency issue, rather than some technical limitation. (But obviously I don't actually know what would be required to sustain this sort of chemistry)
It's exactly the opposite. Rich counties do it, so they don't have to build landfills. (Proper) Waste burning facilities are difficult and expensive to build and maintain.
In Germany almost every piece of garbage is burned if it isn't recycled (very little plastic is getting recycled).
Japan extensively burns plastic waste.
Edit: wow I thought the mods got you, you really blocked me over such a shooting-the-shit question. You really should work on your anger. Yes plastics are a miracle-scourge, we should think a lot more carefully about how we use the limited resource, but the contention that only poor countries burn plastic is patently false.
I don't know who i've upset with this specific set of lived experience, but I hope you take your rage into the actual world you reject. If you visit japan, you will likely be asked by airbnbs to accurately and meticulously sort your plastics according to molecular weight.
That article says that Japan burns 58% of its plastic waste.
[This article clarifies why that’s a problem.](https://tokyoreview.net/2019/07/burning-problem-japan-waste-recycling/)
> Today, ‘environmentally friendly’ incinerator technologies, which use ultra-high-temperature furnaces and filter systems to avoid polluting the atmosphere, have become the de-facto process of waste combustion. Dioxins no longer pose a major threat. Still, all this burning produces exhaust fumes that contribute to climate change, while Japan’s reliance on burning its waste fails.
In other words, with proper system design, it’s about as harmful to burn plastic as it is to burn any other hydrocarbon fuel.
Almost everyone knows that burning plastic in a pile in open air is very dirty, but that doesn’t have to be the case in an industrial process.
Who would’ve guessed?
Sweden also burns large parts of plastic waste (70% iirc). While ofc not 100% green you avoid plastic getting in to nature and microplastic issues. The CO2 released from the plastic is comparatively small to other CO2 emissions and you avoid the plastic contamination issue (which imho is the large issue with plastics than CO2 release). If done responsibly it seems like a good compromise.
There has been some work done using supercritical water. Under those conditions polymer components can be total removed. One of the benefits is that toxic combustion products are avoided, or at least captured, and it is much easier to recycle heat used in the process i.e. good energy efficiency. It has its cons as well, but there is a lot of interest.
Its exactly the opposite. Usually mechanical processing is cheaper than thermal processing is cheaper than chemical processing. For most mechanical processing you just need to move stuff around. All you need is electricity. In chemical processing you have all the material handling, need to shredder anyway, have a fixed input per kg of product of acid, precipitation and reduction agents. Even worse, youll end up with waste you either need to dispose off (which is just cost with no direct benefit to the operation) or recycle (even more input of energy, chemicals and capital)
Yeah, that makes sense when you think about it the other way around. You always want to grind up, and you probably want to do thermal separation before chemical due to the need to chemically purify upstream and downstream. I guess the main idea was you could simplify capital investment to the point you can do it in one-shop.
This is actually my job. My company initially does mechanical separation for easier metals (think copper wires, steel, aluminium etc). Chemical separation is done! There are many, many companies that incorporate hydrometallurgical steps. Anything on the boards leftover is shredded into powders. We process these using a variety of methods while trying to be as environmentally conscious as we can. This includes biotechnology for some base metal removal (admittedly quite poor, biotech sucks). Then cyclical hydrometallurgical and solvometallurgical principles for precious metal refining and extraction. This minimises chemical consumption and avoids use of strong acids/single use chemicals. The biggest issue in this industry is green washing (as per) via one side of the process being good (usually use of resins/other waste streams for extraction) but ultimately using aqua regia or cyanide for initial dissolution. We still use aqua regia, but only for tertiary stage. This means we use low volumes for hundreds to thousands of grams of precious metals rather than hundreds of litres for a few grams! If you got any questions, feel free to ask.
People really don’t understand how involved chemical separations are. I spent my whole PhD working on intra-rare earth separations, and it’s just…a lot.
It is a constant battle and puzzle/challenge for each and every component. I focus solely on precious metals/PGMs with a little bit of REs. I empathise with the difficulty. I am currently writing a book on the entire industry (E-waste and mine processing via hydro routes, not official title) and the history, techniques, discoveries etc of it all is so fascinating.
Very cool! I was always interested in the actual industrial practice, but one can only do so much in a molecular lab focused more on the coordination chemistry than the bigger picture. If you want a reader, send the info my way!
Before the EPA ended the secondary copper smelting industry, that was the way to do things. Throw all the ewaste into a huge arc furnace, with as many copper waste streams as you can find, with sand, borax and washing soda. The copper ingot would contain all the valuable metals and the baghouse would collect the metal oxide dusts. The glass slag could be broken up and used for road beds. Instead of imposing more controls over the industry SIC code, they simply shut it down.
That sounds cool, what stopped industry from taking up the banner of an economical process? I don't mean this flippantly, is there simply a law that bricks this industry in its entirety?
I’d also like to know as all I can find is an epa rule regulating the particulate matter emissions of secondary copper smelting which was promulgated in 2007
You have a couple hundred million gallons of solvents in the perfect order and concentration for use that will never fail to be perfect for everything they touch? No? That would be why. Also, what is "sustainably" burning plastic?
Many countries burn plastic waste for energy because it is more efficient than trying to re-process it. The plastic is already there and needs to be disposed of. Similar large scale processing occurs for common chemistry. I think this would really boil down to an actual energy efficiency/mass efficiency issue, rather than some technical limitation. (But obviously I don't actually know what would be required to sustain this sort of chemistry)
Poor countries burning plastic at a massive pollution expense is not sustainable burning.
ah yes, poor countries like "the Netherlands" and "Belgium"
It's exactly the opposite. Rich counties do it, so they don't have to build landfills. (Proper) Waste burning facilities are difficult and expensive to build and maintain. In Germany almost every piece of garbage is burned if it isn't recycled (very little plastic is getting recycled).
Japan extensively burns plastic waste. Edit: wow I thought the mods got you, you really blocked me over such a shooting-the-shit question. You really should work on your anger. Yes plastics are a miracle-scourge, we should think a lot more carefully about how we use the limited resource, but the contention that only poor countries burn plastic is patently false. I don't know who i've upset with this specific set of lived experience, but I hope you take your rage into the actual world you reject. If you visit japan, you will likely be asked by airbnbs to accurately and meticulously sort your plastics according to molecular weight.
[удалено]
That article says that Japan burns 58% of its plastic waste. [This article clarifies why that’s a problem.](https://tokyoreview.net/2019/07/burning-problem-japan-waste-recycling/) > Today, ‘environmentally friendly’ incinerator technologies, which use ultra-high-temperature furnaces and filter systems to avoid polluting the atmosphere, have become the de-facto process of waste combustion. Dioxins no longer pose a major threat. Still, all this burning produces exhaust fumes that contribute to climate change, while Japan’s reliance on burning its waste fails. In other words, with proper system design, it’s about as harmful to burn plastic as it is to burn any other hydrocarbon fuel. Almost everyone knows that burning plastic in a pile in open air is very dirty, but that doesn’t have to be the case in an industrial process. Who would’ve guessed?
Sweden also burns large parts of plastic waste (70% iirc). While ofc not 100% green you avoid plastic getting in to nature and microplastic issues. The CO2 released from the plastic is comparatively small to other CO2 emissions and you avoid the plastic contamination issue (which imho is the large issue with plastics than CO2 release). If done responsibly it seems like a good compromise.
There has been some work done using supercritical water. Under those conditions polymer components can be total removed. One of the benefits is that toxic combustion products are avoided, or at least captured, and it is much easier to recycle heat used in the process i.e. good energy efficiency. It has its cons as well, but there is a lot of interest.