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  • Low grade boards - depopulating..

    Hi guys,
    Just thought I'd open up the topic of low grade boards and perhaps identifying which is the best way to jump as far as value goes.

    I've recently been sorting some tubs of boards thrown aside years ago, before I even knew there was a market for them!
    I've watched most of Ben's videos on grading and depopulating boards, but just wondering what everyone does here..

    Mid grade boards, slot cards and motherboards etc are fine - no problems with storing those until I have a good load to cash in.

    But as for low grade... I started sorting power boards from other low value ones, such as panel boards with just switches and others with no obvious value such as LCD displays.
    I then filled a largish tub with power boards and struggled to get it to 10kg in weight! At Ben's current price of 22c/kg - that's only just over $2 for the tub full! Definitely not worth the effort to stack & store tubs of power boards for such a small return.
    So - what to do?
    I could rip the transformers & copper coils off - at least they are worth storing at 50-60 cents/kg. I'll certainly pull any IC chips & crystals off as storage isn't an issue with them... and I can grab any large Alum heat sinks.
    The remainder of the boards can go in a box to take to the local transfer station ewaste drop-off point with the scrapped out TVs and other stuff I don't want.

    But, before I do that - is there anything else I should pull off the boards? I know you don't usually find MLCCs or Tantalum caps on low grade boards. I believe there's a fair percentage of copper in mosfets.. but are they worth it? Would a scrap yard buy them? What about your standard small black transistors? Any gold recovery possibility with those? I know resistors, most capacitors and diodes really have no precious metal value. Anything else?
    Any thoughts on all this would be most welcome
    Cheers,
    Chris

  • #2
    As I live in Tassie I dont have any option for selling boards that I know of.
    So I have been slowly depopulating all my baords and I am going to see If I can do some processing of the boards themselves.
    It will possibly be years before I get a chance to start doing this...

    Comment


    • #3
      Hi Chris

      Basically I depopulate all boards searching for precious metals, copper, transformers, aluminium and any obvious value. The partly depopulated boards are then stored in drums and the plastic tub linings from fridges. I have mega heaps. Did sell some a long time ago, I think for about 20 cents, but we can't remember where that was, although my cohort up here has a lead on somewhere. As they cost me nothing, I don't have a problem storing them. I have plenty of room, 35 acres.

      Really my great interest in boards is for the precious metals. The others things are just nice to have. So obviously I collect various chips, flat packs, transistors, MLCC's etc. The MLCC's are what they are, tantalum capacitors when you find them are obvious. Gold plated fingers are good along with gold plated pins and ribbons. Sim cards and mini chips from printer cartridges and jumper pins from computer boards. Also come across a lost of boards that have various gold plating on them. Flat packs and transistors are a mixed lot. Older boards provide better opportunities than later ones. Old metal can transistors are often very good for gold legs and plating.

      So all flat packs, transistors and computer type chips need to be crushed or pyrolized before chemical processing. The rest of the stuff can be chemically processed in various ways to recover any gold or other precious metal. Tantalum caps and MLCC's have their own process.

      One of the most popular refining methods for backyarders is of course Aqua Regia. It works but is quite a process of repeating steps to get a purity of 99.9%. It can also be very messy and of course bloody dangerous. After speaking to a mining engineer mate of mine, with lots of hands on experience, I am seriously considering using a cyanide based method. It is truly a one step method, and a lot easier to go after whatever else is in the mix such as silver and even copper. Clearly there is a lot of copper involved in refining e-waste. Also dangerous, but what chemical solution isn't. However it is a more enclosed and simple method than AR.

      As for what you get from e-waste, it is minuscule, so you need volume. For instance, if you had a kilo of gold plated pins, which average 0.0088 gr of gold per gr of pins, you would have about .2829 troy ounces. So at roughly $A2,000 per troy ounce, you have around $565. However gold recovery on all things electronic is not equal. For instance, flat packs contain on average about 0.002 gr of gold per gr of product. So you really need a lot of them, but there are a lot available. At last count I have about 35 kg of them which could be worth as much as $4,000+. I don't know what the silver content of flat packs is, but there is probably more silver to be recovered than gold.

      I also collect silver oscillators, silver contact points that you find in a lot of electrical parts and switches on computer boards. Ribbon cords on computer boards have either silver or gold ends that are like fingers, again minute but they add up.

      So apart from some experiments, I'm not really interested in refining until I have a large stockpile. And they do not take up much room. Once I sort out the cyanide process then I will run some for a test. Last I read, Ben was also in the stockpiling stage of e-waste components.

      Cheers
      Bill
      OKEDEN SCRAP & PM's
      http://www.okedenscrapandpms.com.au

      Comment


      • #4
        Thanks for your replies guys.
        Appreciate your detailed post Bill - yep, things are less of a worry if you have storage room!
        I think there's a fair degree of "hunter gatherer" in most ewaste scrappers! Many of us really enjoy the accumulation of things of perceived value, with the view of processing and cashing in down the track!"
        My thing at the moment is just to work out exactly what is worth depopulating and storing - and what isn't!
        So you do save the small black transistors? Is there any info on the net anywhere as to their precious metal content? And the mosfets - are they primarily copper, or could there be gold content as well?

        Cheers,
        Chris

        Comment


        • #5
          Chris I have some data which will help you decide what to keep or not. But the attachment is too big for this forum. If you can give me an email I'll send them to you. I have several articals that will help.
          Cheers
          Bill
          OKEDEN SCRAP & PM's
          http://www.okedenscrapandpms.com.au

          Comment


          • #6
            Great, thanks Bill
            I'll send you a msg..

            Comment

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