Yes he did say 9 grams, this was my first attempt at it so wasn't the smoothest of runs I think I lost a little in some sludge but next time will yield better results. To answer the second question, yes definitely considering it also considering trying to source a constant supply of e-scrap.
Would these chips be worth trying to recover the gold from?
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Golddigger76
Well-known member
I'm sure after a few tries you will have it down lol.
Not sure about you but 500 kilos would keep me busy for a while so I would secure those and then focus on finding a supply of material.
That is if you are getting them cheap enough to make a good profit !!!
Not sure about you but 500 kilos would keep me busy for a while so I would secure those and then focus on finding a supply of material.
That is if you are getting them cheap enough to make a good profit !!!
Definitely lol, but yeah will take some time to process. Cost seems to be the main thing, but around where I live the e-scrap is an easier source than carat scrap at good prices.
Why do you guys suggest the gold bonding wires are incased in the epoxy? The ones of done they are right under a fiberglass sheet on the black epoxy. I get hit it a torch of a sec and then just wipe off the bond wires. I’ve burnt the epoxy square and there was nothing in it. I think it’s more of a heat sink.
I do not know what kind of chips you have, but there is no bond wires on the surface of any chips.
The epoxy mix is used as a protection for the chip assembly so nothing moves or are mechanically damaged.
We need to burn off all the volatiles and then crush burn and sift before gravity separating.
A single strand of bond wire is almost invisible.
kurtak
Well-known member
If you are talking about the black epoxy part of the BGA chips like in the pic of the first post in this thread then it is not just a suggestion that the bond wires are "incased" IN that black epoxy - it is a matter of FACT that, that is where the gold bond wires are
And how do I know that to be A FACT ?
Because when I was refining for "a living" I processed batches of those chips in batches ranging from as small as 5 pounds to as large as 30 pound & I can tell you for A FACT that the VAST MAJORITY of the gold in those BGA chips is the bond wires "incased" in that black epoxy part of those chips
Then you are ether doing something VERY wrong &/or you have no clue what you are even looking for
Those are NOT the bonding wires - those are copper leads that are sandwiched between the green fiber part of the chip & the black epoxy part of the chip - which are gold plated - the gold plating in those copper leads add up to VERY LITTLE of the gold that is in those chips
The VAST MAJORITY of the gold is the gold bond wires that are INCASED in the black epoxy
If you do not burn that black epoxy part if the chip to "complete" carbon &/or ash & crush them to "fine" powder to liberate the bond wires that is "incased" in the epoxy you are losing MOST of the gold
In other words - if all you do is only hit them with a torch - just enough to loosen the gold plated copper leads on the bottom of the black epoxy - so that you can "wipe" those leads off - it will take you about (plus/minus) 10 pounds of those chips to get about (plus/minus) 1 gram gold
On the other hand - if you burn the black epoxy to "complete" carbon/ash - & then crush them to "fine" powder to "liberate" the bond wires you will get (plus/minus) right at 4 grams per pound - which means you will get right at (plus/minus) 40 grams per 10 pounds
I can say this for "a fact" because over the course of 10 years I probably processed 500 - 600 pounds of those chip in 5 - 30 pound batches at a time
Kurt
Ok, I have 25 LBs of them. I’ll ash them and grind a pound and see what happens.
I can kinda see now what you’re talking about. The bond wires run from the ring of gold to the chip.
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patnor1011
Well-known member
What you see are not bonding wires but copper traces. Gold bonding wire is in black resin starting where copper wire ends and go to the silicone chip in the middle of black epoxy. You can only see gold bonding wires if you either dissolve or incinerate black epoxy.
Actually, you can see the bond wires, although just the end of them. The left side of the picture have the black epoxy part and the bottom of the silicon die as a large white square. Around the die there are a number of yellow dots and that is the end of the bond wire going up to the top of the die. The epoxy broke the connection between the bond wire and the gold plated point on the fibre base.
On the right side of the picture is the fibre base (a small circuit board) with the copper conductors leading down to the solder side of the chip. There are some copper wires that followed the epoxy cap and was stripped of the base, but where the bond wire broke at the interface you can see the small gold plated spot that corresponds to the bond wire end of the epoxy cap.
The fibre base has gold flash or thin gold plate but it usually doesn't ad up to enough to bother recover it. On the top the gold can be seen in the corner and on the pads for the bond wires. On the bottom side there were probably gold flash on every solder pad, but when the solder ball was formed the gold dissolved into the solder. It comes off as a dark powder if you dissolve the solder.
Last summer I ran a large lot of new bga chips where I had to remove the solder with HCl before incineration. In the end I got a lot of undissolved lead-tin mixed with the gold from the solder pads. Now I have over a half kilo of solder remnants (black lead - tin metal and oxides with about 0.5g gold per kilo... Too rich to get rid of, too bad to recover. 😁
Göran
kurtak
Well-known member
Well hello my dear friend Goran - long time no see - so it is good to hear from you
Thank you for posting that explanation concerning how N/S bridge BGAs are constructed
I was intending to post such a post but you posted almost exactly what I would have posted
Hope all is well with you my friend !!!!
Kurt
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Good to see you mate. Have you been away licking rocks?
kurtak
Well-known member
Only if they are arsenic
Kurt
Kurt
Long time no see!Well hello my dear friend Goran - long time no see - so it is good to hear from you
Thank you for posting that explanation concerning how N/S bridge BGAs are constructed
I was intending to post such a post but you posted almost exactly what I would have posted
Hope all is well with you my friend !!!!
Kurt
Life has it's ups and downs but generally everything is good... though I just dropped a knife on my big toe. 😱
Not the pointy side but the handle first and now I have a black and blue nail and it hurts.
For everyone that wonders why I've been a bit absent from the forum the last years. It all begun when covid struck at the same time as I lost my main income and I had to switch gear. More hunting small jobs and payouts supplementing it with ramping up sales on eBay and Tradera (a Swedish auction site) and that left me with no time for the forum. In three months I managed to get back at the same level as well as making up for the months used to change gear.
A lot have happened during the last years and I've never found the time to spend as much time on the forum as I did before. But I'm still lurking around in the background and often read the threads a week after it's finished. For example I was going to comment on the copper chloride thread but the discussion had always jumped to the next part before I got some spare time.
I'll try to find some time to be more active, but I have to take time to go through all my scrap too, the gold doesn't extract by itself.
Summer of 2023, 30 grams of bond wires. Took me a couple of days to get to this point from BGA chips.
Göran
Taste like garlic!Only if they are arsenic
Kurt
I wish! Right now I'm trying to get into larger volumes of scrapping at the same time I risk loosing my site where I'm working with scrap.
We have to get in touch some day, but now I have to go again.
See you soon!
Göran
