66% or better

Salvaging Gold From Old Electronics

ausome

If you’re hoarding old electronics like us, there’s a good probability you have a decent amount of gold sitting around in cardboard boxes and storage containers. Everything from old PCI cards, IC pins, and even printers have a non-negligible amount of precious metals in them, but how do you actually process those parts and recover that gold? [Josehf] has a great tutorial for gold recovery up on Instructables for the process that netted him an ounce of gold for three months’ work.

After cutting up a few circuit boards to remove the precious gold-bearing parts, [Josehf] threw these parts into a mixture of muriatic acid and hydrogen peroxide. After a week, the acid darkened and the gold slowly flaked off into dust. This gold dust was separated from the acid by passing it through a coffee filter and readied for melting into a single nugget.

Gold melts at 1064 ˚C, much hotter than what can be obtained by a simple propane torch. This melting point can be reduced by the addition of borax, allowing the simplest tools – a propane torch and a terra cotta crucible – to produce a small gold nugget.

For three months of collecting, stripping, and dissolving electronic parts, [Josehf] netted 576.5 grains of gold, or at current prices, about $1500 worth of the best conductor available. Not too bad, but not something we’d use as a retirement plan.

Thanks [Matthias] for sending this in.

Comments

  1. rogier21 says:

    Well 1500 bucks for just dissolving some components is not a bad deal!

    • Will Lyon says:

      Indeed! That’s $500/month in extra income for a little bit of work!

      • matt says:

        Do you realize how much scrap would need to be processed to collect this much gold?

        • fartface says:

          And the toxic output he is probably dumping on the ground or into the sewer. Tomorrow on HAD how to profit from smelting lead at home, Screw your neighbors, you can make MONEY!

          • Ricksl says:

            Anyone with a bit of chem knowledge can easily neutralize most of these toxic chemicals, the point of the cupellation is to oxidize any metals that aren’t gold. Then it goes into the muriatic acid bath where the non-gold metals form metal salts and water through a simple ion exchange. The gold is not oxidized so it does not form a metal salt and instead floats to the top as the other metals are dissolved. With some more chemical knowledge you could even figure out the remaining amount of acid (titration) and the amount of sodium hydroxide you would need to neutralize it, it neutralizes into table salt and water. See not so scary when you know just a little bit of chemistry.

          • AussieTech says:

            What is scary is a chemist who thinks that buffering the pH solves the entire problem, while ignoring all the other metals that are in solution.

          • Ricksl says:

            Besides some miscellaneous metal salts there is almost nothing else in there, and I am sure your local hazmat disposal center would be more than happy to take this waste off your hands instead of dumping it into a storm drain.

          • Kerimil says:

            Had to post this

        • Hack Man says:

          Also, $500 per month minus costs…. disregarding environmental impact….. not exactly a huge money maker.

        • mnadamn says:

          Considering that a cell phone has 0.001 troy ounces ($1.27 on today’s rate), A LOT. The real question is how much would you have to spend in chemicals to treat the 1181 cell phones it would take to make $1500? Let alone, the time it takes to take apart that many phones.

          • Tony says:

            Yeah, I once worked it out as a buck per phone. Woohoo!

            I once for a ‘scrapper’ site, their line of thinking seemed to be “don’t extract the gold, sell the scrap to some sucker”, like those upthread…

  2. andarb says:

    The main issue is that there are many other materials in those electronics which should be processed in their own ways.

    Besides, gold panning in a decent spot is about as good.

    • fonz says:

      I believe there is about 30 time more gold in a ton of cell phones than there is in a ton of gold ore, the mines that process gold ore isn’t doing it for fun

      cellphones/electronics scrap will have other sellable metals and some more nasty stuff
      but the things they use to extract gold from ore isn’t exactly spring water either

      • shocked and annoyed says:

        72g/ton is the number thrown around on ewaste. Ive no interest but I sold one of my old rockcrushers to a guy whos running PCBs through it. He seems to think its a great business…Id rather work a lode than a load of garbage.

        My lode claim averages 42g/ton (1.5oz) in free milling gold. If I was processing sulphides I could increase that significantly, but my operation is pretty small scale, and we have sufficient reserves to highgrade. So for now, we actually are processing with spring water…and gasoline for the crusher.

        If the 72g/ton is accurate than sure, a scrap heap is richer than my hole in the ground. But I know where my hole is. I have a significant reserve thats right there waiting for me to work it. Ewaste would require acquisition, storage, processing, and waste disposal….and uncertainty of supply. Ill stick to finding new metals and leave recycling to someone else.

        My placer claim is on a great river (I get between .75-1.25g/yard) but since CA has a ban on dredging I am lucky to pull an oz or two in a month and its actually alot of work. With dredging on the same claim I used to pull about an oz every 2-3 days. At this point we use it more as a campground than a gold claim. End of last season we strategically placed a number of gold traps so hopefully we will get a decent capture by next summer.

        • Greenaum says:

          I never met a guy who had his own gold mine! Is it all about processing rock nowadays? Nobody bothers digging in to find seams, and nuggets as big as yer fist?

          Whatever processing you need to use on sulphide, whatever that is (not a lot of gold miners where I live), I hope you’re keeping the waste. Or maybe you could sell it to a factory who do that themselves? Or do they only want the raw ore so they can get at the easy stuff as well?

          Anyway, pretty interesting.

          • shocked and annoyed says:

            Nuggets as big as your fist are the dream….I once found one the size of my thumb….but most of my gold ranges from grains of sand to breakfast cereal size. I get some decent size chunks of silver and copper though.

            I have an extensive tailings pile from the previous generations of miners. I do a pretty even mix of new digging and processing old tailings that werent worth it back in the day but are with more modern equipment.

            My own “tailings” are separate from the historical ones. Refineries would take either sort, if I had assays done to determine actual content….but as odd as it may sound. I am not in it to get rich. Its more of a semilucrative hobby. It becomes very expensive and very bureaucratic if I were to scale up much from where I am at. Maybe one day.

            The big guys are all about processing tonnage. My mine has just over 100years of history. So my operation is more about finding offshoots, and areas that werent considered rich enough to be pursued way back when, while pushing forward along several areas that just hadnt been finished at the last closure in the 40s.

            Im really just a recreational hobbyist….but I use powered tools I have to file a “plan of operation”. Since I work an unpatented historical claim as long as I keep my tonnage low and machinery light I avoid alot of the expense of “reclamation and remediation”. If one day I decided the ground was hot enough, and I was motivated enough, Id have to put up an expensive bond to scale up.

            as they say MO Money MO problems.

            I started out panning, moved into dredging….I had put on alot of weight, deskjob, and was having stress related health issues. When I was a kid I loved camping, but just lost the desire. I hadnt taken a vacation in 4 years when my doctor told me I was shortening my life with my lifestyle. My kid found a “gold panning vacation” thing online. We spent 2 weeks and left with less gold than the trip cost us….but I enjoyed myself….got more exercise than Id had in 10 years…and felt so much more relaxed having gotten away from it all….that I was hooked.

            In my teenage years I was a novice spelunker…when that came up in conversation with a dredger up river from us he invited me to visit an abandoned mine he had been doing metal detecting around. We roped off and I took him on a 150ft shaft decent, and we spent a few hours exploring. I was hooked and spent my entire seasons take from the dredge, and a chunk of my 401k, to buy my claim from a speculator who was filling claims over historical lodes with expired documentation.

            My first season I got most of my gold with a broom, a shovel, and a shopvac…just cleaning up and opening tunnels. Ive come along way since then but still have much to learn…its a very expensive hobby, good equipment isnt cheap at all. Ive recently started welding classes so I can try my hand at building some equipment….who knows maybe one day Ill put together something worth submitting here as a “gold hacker” lol.

            I know more guys whove gone bust then struck it rich….but I know alot of guys who feel richer for having the itch. I joke with my kid that in a few more years, when the rest of my hair goes gray, Ill grow out my beard and retreat to the hills….I really hope they lift the moratorium on mining patents before Im too old….Building a cabin at the mine to retire would be a dream.

        • fonz says:

          I was thinking of the big mines where they crush tons and tons of ore then mix with cyanide and other chemicals to extract the gold, the ore can be down to 5g/ton

        • SavannahLion says:

          You’re a dying breed. We (as in family) owned claims for probably nearly 50 years. We finally let them go shortly after my father passed. Without getting into details, as much as I would have liked to keep them it was just the realities we faced. To this day environmentalists still irk me given the amount of damage they do. it was an environmentalist who burned down our structures resulting in a massive forest fire about thirty years ago. Made it easier on us to do our mining with all the trees gone since then.

          But I digress. Keep it and enjoy it for as long as you can.

  3. optimus prime rib says:

    silver is a better conductor of both heat and electricity than gold. Copper is also more electrically conductive than gold.

    • Hack Man says:

      Thermal conductivity (4 highest elements listed):

      1. Silver (highest): 4.29 W /cm K
      2. Copper: 4.01 W /cm K
      3. Gold: 3.17 W /cm K
      4. Aluminum: 2.37 W /cm K

      Electrical conductivity (4 highest elements listed)

      1. Silver (highest): 630,000 /Ohm cm
      2. Copper 596,000 /Ohm cm
      3. Gold 452,000 /Ohm cm
      4. Aluminum 377,000 /Ohm cm

      • Hack Man says:

        Diamond is actually a much better heat conductor than silver, around 5 times better for an average diamond.

        Then we have superfluids. A particular state of liquid helium that forms under 2.2K degrees has been shown to conduct heat as much as 100 times better than the best diamonds.

        • 0c says:

          And here we can observe the Common Pedant in his natural environment. Stay quiet folks! It’s not because they’re easily spooked, but rather for our safety (getting lectured to death is a terrible way to go).

          Crikey!

          • Hitek146 says:

            I still don’t understand why being a pedant is bad. Somehow folks these days have an unnatural aversion to being corrected or elaborated upon. To me, this is just more welcome information. Grammar and punctuation is no different. It’s as if, somehow, it is now politically incorrect to be as accurate as possible. Being accurate, even on internet posts, helps to proliferate accuracy. Why this is bad, I have no idea…

          • Hitek146 says:

            “Grammar and punctuation is no different.”
            Before I get attacked for being a hypocritical pendant myself, the former sentence was a quick, improper, shortening of the sentence “Correct usage of grammar and punctuation is no different.” I also could have just used “are” instead of “is”… :)

          • Joe says:

            Grammar or punctuation is / Grammar and punctuation are

          • impromptuParade says:

            Actually, the subject is the singular ‘usage’, here, not ‘grammar and punctuation’. ‘Is’ is correct.

        • Rob says:

          Which element is diamond?

    • dioxide says:

      yes, but gold is chosen because its oxidized/tarnished form is still a good conductor.

  4. potatoman412 says:

    Pretty neat. I had watched a couple of vids in my weekly trawling last week that were in the same vein (npi). While this process is fairly safe and cool, I also enjoyed this guy that pans for gold in the streets of NYC. A little off topic but others may enjoy this as well. http://www.youtube.com/watch?v=hxG8HBy3hpk might as well collect all that bling that gets lost lol.

  5. dioxide says:

    time to make some exploding wire detonators, or perhaps some graphene batteries. chop chop, get to work.

  6. Tom Hargrave says:

    So, what happens to the metals you burn off? Every metal you separate from gold is a heavy metal and most are toxic to fish.

  7. matt says:

    So has the author verified that this is 99.99% or better gold? I’m assuming no, and I wouldnt be surprised if there were other impurities in it which would effect the price. I was always under the assumption that gold was refined with cyanide.

    And since when could a propane torch not reach 1060C? According to wikipedia it gets up to 1995C and 2820C with oxygen.

    Anyways I doubt any coin store is going to give you $1,500 for a home made nugget if you havent gotten it assayed.

    • Hirudinea says:

      A pawn shop would probably give you $1K for that nugget, not bad for old garbage.

      • matt says:

        They dont know if it is gold platen tungsten. If they believe it is gold, they wont know the purity, so they likely wont give you anything, especially when you tell them you made it yourself.

        • Hirudinea says:

          Pawn shops deal in scrap gold all the time, you can test for the relative purity of gold in several ways (acid test for one) and for such a small piece of gold they could cut it in half with tin snips to test for a tungsten core. If its gold, which it is, a pawn shop will buy it, and any one that didn’t wouldn’t be in business very long.

  8. Rob Smith says:

    just to be really picky, silver is the best conductor of electricity, gold is used in contacts as its a noble metal and under normal conditions does not tarnish

  9. Nonya-Biz says:

    probly get better results without all that brass.

  10. MS3FGX says:

    He says in the comments that the smelter he is dealing with has a minimum of 1 LB before they buy any metal from him.

    So I guess we check back in another 3 years or so?

  11. Absolutely brilliant. It reminds me of a program about guys in India who sweep the streets to get gold dust (and go down sewers, and other fun places!). Not sure if it’s available worldwide, but here’s the video on Youtube:

  12. Jehu says:

    Just looking at his method there are some major steps he has missed and a lot of wrong information in there. He doesn’t explain some of the pit falls in the methods, such as putting mixed metals, plastics and components in the same batch. He doesn’t explain what to do with the base metals from the pins which IIRC is a beryllium alloy. Preparation of the crucible? Humm, missing. Safety? What?

    There are a lot of extra things you have to worry about with gold recovery from e-waste. Epoxy filled fibreglass boards, chemical disposal. You need a good metric Tonne of motherboards to get one ounce of gold. You know what the biggest money spinner in E-waste is?…….It’s the plastics and steel. Gold is just the cherry on top.

  13. “Gold melts at 1064 ˚C, much hotter than what can be obtained by a simple propane torch.”
    This may be the case for some setups, but there are still cheap torches that can reach these temperatures with a few well-placed bricks. This tiny forge doesn’t give room to weld or melt anything but tiny quantities, but that’s fine in this instance. Wiki says max flame temp for propane is 1,995 °C in air, or 2,820 °C with oxygen. That’s well above the melting point of Aluminum, brass, and even iron! http://en.wikipedia.org/wiki/Propane_torch
    I only happen to know this because I’ve been looking into casting metal using lost-wax or lost-PLA processes. I want to make it easy for us to RepRap metal parts by printing molds out of plaster of paris, using a Universal Paste Extruder. Imagine printing your own hot end, or casting a replacement engine part in an afternoon!

  14. Someguy says:

    Prices for circuit boards start around $2.50/lb if you strip them out and take them to a scrapper. Extension cards and denser circuit boards from e.g. hard drives are more valuable. By the time you’ve filled a box about the size that you’d use to store file folders you’ve got about $80. At that point there are several online sites that you can ship the scrap to.

  15. Galane says:

    What about recovering the silver, rhodium and other precious metals used in electronics? To make recovery easier and more thorough I’d get one of those blenders in the Will it blend? videos. Chunk the stuff up then pulverize it so the acid can get at all the fine particles.

    Once the insoluble gold is out, there’s all the other good stuff dissolved in the acid. If there’s a solution that only dissolves silver, that could be used first then the silver extracted, probably by electrolysis onto a piece of silver.

  16. Joseph Lane says:

    A propane torch is in fact hot enough to melt pure gold. I have done it myself with 24k casting grain on top of a chunk of graphite (to maintain purity). I used to melt pure silver on top of fire brick but found it was adding contaminants and modified my process as a result (there is no way I would have tried that method with gold). I also agree that the nugget in the picture does not appear to be pure gold; though I didn’t spend any time analyzing his chemical process to determine what else might be in the mixture.

  17. Some of the other elements in phones as well as the expensive hard-to-buy parts such as LCDs can actually get higher prices from fellow hackers than the gold.
    I’ve seen 3310 screens go as high as £12 on *bay and the higher resolution ones for even more.
    Also there are often Bluetooth chips in these which can be harvested for reuse and the SIM slots, microSD/etc and all sorts of handy widgets like small speakers, mics, accelerometers… the list goes on.

  18. ejonesss says:

    i think in today’s day in age with drugs especially meth on the rise having a home set up may be asking for the police to check in.

  19. pcf11 says:

    Fuck scrappers I’m keeping my vintage collection of electronics.

  20. Eirinn says:

    Isn’t everything electroplated these days? Can’t be much on those contact points.

  21. static says:

    I’m pretty sure Josehf’s retirement statement had much of his tongue in his cheek. At any rate he should have ended up with more money in his pocket with very little physical effort.

  22. svofski says:

    In the former USSR a lot of electronics was made with generous amounts of gold, and other precious metals. This is the primary reason why old soviet computers or their parts are rare and hard to find: gold diggers destroyed them all. Not cool.

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