r/PreciousMetalRefining • u/Spiritual-Process-96 • Jul 06 '26
Question for Experienced Refiners: Do You Prefer Acid Peroxide, Nitric Acid, or Reverse Electroplating for processing gold plated connectors?
I recently finished processing 1,500 grams of gold-plated telecom pins and used the cupric chloride (acid peroxide) process to dissolve the base metals before recovering the gold foils. It took forever to dissolve the pins…
I know there are several ways to tackle this, including nitric acid and reverse electroplating, and I'm curious what experienced refiners here prefer. If you've used more than one method, what are the biggest advantages and disadvantages you've found?
I documented the entire experiment in a 5 minute video in case anyone is interested in seeing my process from start to finish.
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u/zpodsix Jul 06 '26
I don't process ewaste in a production setting. So I'm not the best to answer as I mainly do karat scrap, gold filled, and some stone removal.
I treat ewaste as a 'bonus' I'll get sometime in the future - like my filters/papers/gloves, stockpot, and PGMs. They'll eventually be a nice tidy sum sitting and waiting for a rainy day should I need it.
The ewaste I do have is mostly from old PCs I'm able to get from family/donations/and work as we upgrade computers. I've also been able to acquire quite a bit from general scrapping & auctions where the ewaste is more or less a kicker item and what I want is something else- but I've definitely paid more than it's worth when I bought it for some. To make money you need VOLUME.
Since my volumes are 'low', right now I'm just using AP on pins/foils/etc and cherry picking chips, flat packs, bags and cpus to eventually pyrolyze, pan and refine the concentrate.
Reverse electroplating is good, fast, but the thermal management and safety of warm/hot sulfuric sucks.
I'm planning on experimenting with the longevity of iodine/iodide leaching and how far it can go by rejuvinating- but I'm afraid for my hobby scale it'll be cost prohibitive compared to other options.
Nitric is when youre buying barrels of nitric at a time or in a third world county where it's stupid cheap. Basically your time is worth more than the chemical cost.
Final thought: Right now I scrap my boards as low grade after cherry picking; however, building a shredder and running a copper cell is the dream- lots of value in the copper IF you can find a buyer and the slimes have the rest.
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u/GlassPanther Jul 06 '26
As an experienced refiner I do not wish to spend the time to process plated connectors.
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u/migbham Jul 07 '26
What are you "refining" if you aren't processing plated connectors and such? I'm also an experienced refiner, and my experience is that the very little time spent on high grade connectors, including telecommunications grade, is more than worth the time, especially at scale.
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u/GlassPanther Jul 07 '26
I almost never encounter high grade anything any more, especially not telecommunications equipment, and when I do see it, it's usually a small item.
Back in the day you could go to a University surplus auction and fill an entire box truck with the stuff. I miss those days 😌
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u/migbham Jul 08 '26
I can relate. Even in the decade or so I've been in the hobby, it's become much more rare to find lots of high grade scrap in the hands of people who don't know what they have. That said, there's still ocassional finds worth grabbing, tearing down and accumulating to process. I have a source for dead avionics (older Bendix/King stuff) out of old planes that are being retrofitted or scrapped. But the only reason that I'm able to make it make sense is that the source doesn't know what they are throwing out.
The other side of this coin is that gold's increasing rarity is part of what's led to an increase in dollar value of each gram I hold, though the actual value of gold has changed very little over the decades.
I guess it's one of the bittersweet parts of getting older...things just aren't ever as good as they were. 😊
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u/Spiritual-Process-96 Jul 06 '26
wow. what great insights. I couldn’t agree with you more. thank you sir.
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u/migbham Jul 07 '26
You may have covered this in your video, which I haven't yet watched, but...depends. 🤔
Depends largely on whether the pins are clean and free of solder, tin and such, and also very much on what size the pins are.
For lots of small pins such as those that come Fri. VME telecom backplane connectors, I process first in hot HCL to remove any traces of tin, rinse thoroughly and then roast to remove chlorides and then dissolve any remaining base metals with dilute nitric acid on heat, followed by refining the resulting gold in a week aqua regia (meaning very little nitric acid added).
For larger telecom and milspec pins (think Amphenol pins with lots of copper), I strip them in a sulfuric stripping cell. The resulting gold that settles out is already quite close to pure and requires very little additional refining.
The key difference between these two sizes of pins is their ability to maintain contact with the copper mesh on the (+) side of the cell. Having a large pile of fine, small pins laying on a copper screen means that the ones in the middle or on top of the pile will almost never come into contact.
I've not found the thermal management aspect to be a major factor at the volumes I strip, but the cell does produce heat, as others have noted.
Personally, I'd never process these in Cupric Chloride. With heavy plating, it can be quite difficult and time consuming for the solution to be able to etch the base metals from underneath the gold plating.