Gold recovery from e-waste by food-waste amyloid aerogels | Hacker News Reader

Gold recovery from e-waste by food-waste amyloid aerogels

onlinelibrary.wiley.com

69 pointsBrajeshwar20 comments

We have really good efficient gold recovery. The problem is that its socially and actually toxic: socially because it destroys poor economies to turn them into recovery stations littered with PCBs and bad stuff, and actually because gold recovery typically involves burning things, like associated plastics, and use of stuff like Cyanide which winds up in the waste water stream, peoples body fat, you-name-it.

So this technique may well be less "efficient" but if it's less toxic, and uses another waste stream, it can be worth it.

I wonder when, if ever, it will be viable to grind up chips and things to extract gallium and other trace elements which represent high cost supply chain risks (most viable rare earth mines are chinese because the west is lazy about maintaining their own sources)

cyanide is not a brand name, gallium is not a rare earth element, and almost all rare earth elements are cheap and abundant worldwide

consequently i am also skeptical about your grasp of the things i don't know about, like the economic effects of pcb recycling on poor economies

Fair. The abundance isn't the problem the state of the mines for rare earth and other things is. A couple of options in Australia went to sleep when China cut prices and they haven't woken up afaik. Same with lithium options the price makes Western clean extraction much less profitable and we're not short of cheap lithium.

Snark is frowned upon here. Complaining I capitalised cyanide is pretty snarky but your substantive points stand.

Am I right in thinking your dislike of my shallow economic statements should not be read as believing you think pcb recycling has no downsides? Because you would be in a very small room if you said it's only good to send dead pc parts to Asia and Africa for teardown. Even the vendors now say they know this isn't all peachy.

> A couple of options in Australia went to sleep when China cut prices and they haven't woken up afaik.

It'd be more accurate to describe what happened was a number of resource producers went all in on an anticipated surge in lithium demand for EV and home batteries globally that was much smaller than predicted.

I do wonder, based on the 'state of mines' question, whether phytomining won't be a major source of resources in a more circular economy. The solarpunk in me loves the idea. The Engineer in me blanches at the economic realities. Investing in commercial phytomining is definitely on my 'if I win the lottery' list.

pcb recycling can easily be done in an extremely polluting way, and that's the easiest way to do it, and i've definitely seen that cause problems. i've made myself sick doing it, in fact, though not seriously. what i don't know is how prevalent it is for people to cause problems by doing pcb recycling on an ongoing basis, which i wasn't doing. it depends on the local social context, but i'd think that in most of the world it would be pretty common for their neighbors to oblige them to stop, even if they managed to avoid poisoning themselves in the process (which would also make them stop, in a sadder way)

with respect to capitalizing 'cyanide', there is a fable told by aisopos about this https://tile.loc.gov/storage-services/public/gdcmassbookdig/...

> When people go on a voyage they often take with them Lap-Dogs or Monkeys as pets to while away the time. Thus it fell out that a man returning to Athens from the East had a pet Monkey on board with him. As they neared the coast of Attica a great storm burst upon them, and the ship capsized. All on board were thrown into the water, and tried to save themselves by swimming, the Monkey among the rest. A Dolphin saw him, and, supposing him to be a man, took him on his back and began swimming towards the shore. When they got near the Piraeus, which is the port of Athens, the Dolphin asked the Monkey if he was an Athenian. The Monkey replied that he was, and added that he came of a very distinguished family. "Then, of course, you know the Piraeus," continued the Dolphin. The Monkey thought he was referring to some high official or other, and replied, "Oh, yes, he's a very old friend of mine." At that, detecting his hypocrisy, the Dolphin was so disgusted that he dived below the surface, and the unfortunate Monkey was quickly drowned.

while i am not advocating drowning you in the mediterranean, i think it's reasonable that, if someone thinks 'cyanide' is a brand name, we should ignore their opinions about the toxicology of cyanide; and, if they express those opinions with great confidence, as you did, we should probably also ignore the other opinions they express with great confidence

A great read except you elevated a tablet keyboard miskey/typo into intentionality. Having worked in a marine biology lab with reagents long ago, I know the difference between Analar products in a jar and their name as chemical substances.

Maybe a little charity?

I do not, and never have thought cyanide is a brand name.

fair enough, perhaps my interpretation was biased by its close juxtaposition with other common chemistry misconceptions

You mention a social problem, but it's an economic / capitalist problem; countries have been exporting and trading e-waste to the highest bidder that in turn sends it to the cheapest labor to get any value out of it.

Waste should be processed as close to the source as possible, and waste should not be exported unless it actually gets processed properly, that is, if exporting to a country with good recycling facilities instead of putting it in landfill/incinerators.

But the checks and balances for that are poor. IIRC / I have no source and may be making it up, in western countries, plastic is ticked off as "recycled" when it's been separated and baled up; if it's then exported and burned, landfill'd or chucked in the ocean doesn't matter anymore, the country fulfilled its pledge of recycling plastic.

People have been trying for over a hundred years to find ways to extract gold and other precious metals efficiently from seawater, where the supply is virtually unlimited but extremely dilute. When I saw this article my first thought was, maybe this is finally the stuff that could do it.

The Shai-Hulud of the sea.

Desert Power TNG

I think you could extract Vanadium from seawater by farming sea squirts.

https://en.wikipedia.org/wiki/Vanabin

NOAA claims there is 1 gram gold / 100 million metric tons of seawater[0]. Even if you could refine it, there has to be other valuable materials at significantly higher concentrations with a plausible profit margin.

[0] https://oceanservice.noaa.gov/facts/gold.html

That's ten grams per cubic kilometer, and given the volume for the Atlantic Ocean I can see in Wikipedia [0], that'd be 3100 Metric Tons of gold, that is around the global yearly production of gold [1]. It's a big number, but yeah, probably there's something else more expensive. Like salt.

At today's price, that's around $650 of gold per cubic km.

A cubic km of Atlantic water, having a salt concentration of 3.3%, would have around 32 million metric tons of salt. At today's cheapest price of 8$ per ton of salt in brine (that I don't even know if it's correct, but i got it from here [2]), that'd be $240 million per cubic km. Way more profitable per cubic km of water (if you don't factor the cost of moving 32 million metric tons of anything :D )

  0: https://en.wikipedia.org/wiki/Atlantic_Ocean
  1: https://en.wikipedia.org/wiki/List_of_countries_by_gold_production
  2: https://www.statista.com/statistics/916733/us-salt-prices-by-type/

And you'd have to move and process that one cubic kilometer of water as well, which sounds easy on paper (just use a pump bro) but that's err. 1.000.000.000.000 liters of water. Heating that up by 1 degree takes 4 kW per liter, or 4 petawatt for the whole lot.

Ridiculous scales, in any case. If I were to think creatively, I'd create a compound or a filter creature that accumulates gold particles naturally and concentrates it. I have no clue what that involves.

I did some back of the envelope calculations, there is 1 gram in 100 million metric tons of seawater [0] and there is an estimated 1.3x10^18 metric tons of seawater on earth [1] then the total amount of gold in ocean is about 13,500,000,000 grams of gold

let's do a thought experiment..

think of a modern passenger airplane. That airplane has thousands of specialized parts really.. each one made of plastic or metals or other.. together, it makes something that has enormous, powerful benefit.. to travel over water and mountains and neighbors, to get to a destination and very quickly. Each of those airplane parts could be "recycled" at the end of life, but a) they are unique to their purposes, not made to be generally recyclable and b) the materials are often very low cost in terms of the raw material inputs.. manufacturing starts to mature like that.. so any recycling value for just the materials, is likely low from the material point of view alone..

Now, with that example in mind.. think of a PC computer or server rack mount computers .. each part could be taken out.. the value of the material itself, and the lack of recyclable design.. makes each part very low value and difficult or impossible to recycle.. and here is the conclusion..

The very high value of the complete device or airplane, is completely lost once more than a few parts are removed. The "value chain" of reuse is destroyed quickly.. with the scrap being far, far less value than the thing it came from.. this is a giant loss of energy in more than one way, and a giant source of waste in the deepest sense..

Your analogy would break down as, if the airplane were intact and had good chain of custody, then the owner would at the very least sell it to a junkyard that would part out the most valuable parts. More likely it would be sold to be reused.

The challenge is the capitalist strategy of manufactured obsolescence that make valid products turn into complete junk to sell new product.

That and the proliferation of cheap ill designed products are the largest source of waste in the world.

While recycling may not be cost effective in some cases, for what it’s worth there is a thriving remanufacturing market of airplane parts.

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