I save the chips up. Theres several grades that I work by and its probably different from what every one else does.
These are from all the boards I get. As its not worth shipping normal random green boards from NewZealand, I just cut the chips off them to save up. The boards are normally from printers and random electronics like TVs and such, anything with a chip on it really.
I put aside any boards from computers to sell .
CPU well you know what CPU are and how they are seperated.
Flat chips with a green base and a Gold triangle on the corner. These have a Gold plated Copper 'heatspreader' inside them, and Gold wires.
EPROMs. With the little window on them. They get divided into 4 sorts, Gold wires and Silver wires, and Gold paint under the actual chip, and Silver paint. The paint acts as a heatsink. Gold was cheap back then....
EPROMs. Black resin sort. They normally have 'j' shaped legs. If they are 'socketed' into a surround on a board that I am sending away, they stay there in the socket.
If they are not on those boards, or if they are soldered onto a board I pick them off with a screwdriver and put them in their own bucket.
Normal IC chips, the sort thats got legs soldered thru the board. I cut off with a boxcutter, one slash down each side and pick them off. Its not that hard on the blade and i can sharpen up the worn edge with a knife sharpening stone. Just be carefull where your other hand is, and whats in front of the blade if you slip. I tend to hold the board against the wall and do it that way, downwards with the knife.
Flatpacks. Any chip thats thin and flat and has got legs soldered to the board. Real easy to cut off. I go and cut all the right hand sides of all the chips on the board, then turn it around and slice thru the other side. Most of the 2 sided chips fall off and I turn the board 90deg and cut the third side of the 4 side chips, then the last side.
I also rip the big 3 legged transistors off, most are actually power transistors. They have Copper in them.
With them, I put them into a large coffee can or such and put the cap or lid on and poke a small hole thru the lid to get the fumes out without letting oxygen in, then throw that into a fire and roast the container to burn the resin off the Copper legs and backing heatsink.
After its roasted I seive the carbon from the legs and heatsink using a
microwave door. (which is absolutley perfect for the job!.)
OK, the scrapbuyer probably will raise their eyes at seeing this Copper, so I find a Copper pipe and crimp one end, fill it with Copper and crimp the other end. Thats OK with my buyer as I explained what I'm doing and why.
For a first timer, just bring the Copper bits in in a bucket and show them. Talk to someone who can make the desisions and they will probably agree with me.......
Now, the flatpacks... Same deal as above. Use microwave doors to sieve the legs off the burnt flatpacks or such. Use different doors (to get different hole sizes) to grade the sievings.
At the moment theres 4 things in your roasted chips. Burnt carbon, Copper legs and the Gold wires that are attached to the legs, and the actual chip with the Gold wires stuck to them.
The Gold wires will probably seperate from the chips with the heat, but will still be stuck to the legs a lot of the time. Sieving will help break off the Gold wires from the legs.
But, must of the Gold wires will be in with the carbon black ash.
Thats when you go 'old school' and use a Gold pan to pan out your Gold wires.
Recrushing/grading the carbon black will get some more Gold from it.
Save the carbon black as no matter what you do you will not get all the Gold out of it. Theres ways to get this Gold but its not something that the ordinary person should do and don't ask how to do it here on SMF.
We have a very deeply scribed line that we do not cross when it comes to chemicals.
It would be possible that a toll refiner will be ble to get this Gold (its just part of the processes that they use for other stuff) or, just sell the chips or get a toll refiner to refine the chips for you. Their profit margin is less than the difference of Gold return between your result and theirs, so you do not loose money anyway. (Yah gotta get all the details of their return and costs first though) If you take your time into the calculations its probably easyer to sell the chips or toll refine them.
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Theres something I am trying to find out about the normal chips too. Some chips that have broken as I pick them off (sometimes just grabbing the 8 leg chips with pliers and twisting breaks them off quicker than using a knife).
Some chips had 'tinned' legs (silver colour but not Silver) but directly under where the resin was they are plated Gold over the leg. I dunno why, maybe to get a better weld when they weld the Gold wires on? Weird. These were older chips, early/mid 70's Star brand electronics - printers and such.
I have not done a lot of research into breaking chips open to find out how often they do this or such.
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On Goldrefiningforum.com theres a thread about the above roasting chips process.
Its called 'patnors method'. Search for it and read it 3 times before asking questions here.
Just don't ask any questions there about it or using chemicals or such or anything at all at GRF.
That sites for 'refining metals' not 'Scrapmetal'.
I have a reasonable knowledge of chemistry and its dangers and tried before finding GRF online to recover Gold from scrap. Its simply not worth it as my returns will always be lower than a toll refiners, and far far more dangerous than a toll refiners.
And including time and gear $$ value, just selling the chips to a buyer in most cases (not here in NZ, postage costs are NZ$50 per 2.5Kg (5 + 1/2 pounds for you imperialists) will get you a better $ return.
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