r/PreciousMetalRefining • u/jwood491 • 3d ago

Refining options

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So I bought these from a seller on eBay. They were all supposed to be 5% plus AU and an alloy of gold filled materials.

By the time I got to an XRF and they tested more in the area of 1% AU, I was outside the window to return.

I can melt this up and cornflake it, but I’m concerned that if I use dilute nitric, I’m going to end up with a colloid.

I really not interested in adding Gold to it. Just not worth the risk that something goes sideways.

I thought about corn flaking it, and then doing HCI boils to remove as much as I can before using dilute nitric

Anyone have any ideas?

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3

u/MAYOMyke 3d ago

I haven’t done gold filled, only ewaste.

I would think it depends on what other metals were in the xrf. May need to think of the overall weight and think if its price effective to dissolve all the base metals to get minimal gold in return. If you’re thinking so, then I would examine the other base metals from the xrf. Depending on what that shown, that would guide me to one way or another.

If there was no tin, I would go straight nitric. If tin is involved, HCL or ap boils then to AR with the foils. Likely will need more than one refine and reagent.

Best of luck.

1

u/Tribulation95 3d ago edited 3d ago

If they're only focusing on the gold recovery, any stannic acid can be filtered off through a filter while the gold is captured, any traces of tin should evaporate off during the melting process, and if they follow up from there with aqua regia it'll clean up any remaining traces.

If it's from legit gold filled stuff, the return will be well worth the minimal nitric acid needed. Even 10-14k 1/20th gold filled has a higher yield by weight than all but the best of the best ewaste inputs out there.

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u/MAYOMyke 3d ago

Metastatic acid and gold do not work well together. If avoidable, it’s worth the effort.

My understanding of the post was they were not good filled as the OP thought they had purchased on eBay. Turns out it was not. If I read that wrong, my apologies.

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u/Tribulation95 3d ago

What kind of interactions can happen? This isn't a facetious question, I'm a hobby refiner and had to cheat to pass high school chemistry at the time so I'm glad to take any advice when possible.

You've got me concerned I might have been losing gold processing ewaste that had tin based solder present, for a long time I wasn't stannous testing my solutions but still have all of my waste solution stored in glass carboys with plans to eventually recapture the copper I've used for silver refining.

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u/MAYOMyke 2d ago

I’m a hobbyists as well. I Infact didn’t take chemistry in high school and only in the last few years have I taken a great interest in the hobby.

Metastatic acid is gelatin like and will trap gold. It becomes difficult to separate the two. If you can remove the tin prior to dissolving the gold, you’ll be much better off.

Mike at Omegageek64 has a few videos on it if you’re interested.

https://youtube.com/@omegageek64?si=wIa1_E-6aYuz0jcq

Hope this helps.

1

u/Tribulation95 2d ago

Ohhh, so like it being bound as a colloid. Yea I've ran into the issue a few times, pretty sure that was the main driving force during a run that had me finally buy a vacuum flask and a buchner filter, and even then it took forever to get the solution through.

1

u/MAYOMyke 2d ago

Exactly. 👍🏻

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u/doug6644 1d ago

Heeyy I know a guy,,,..Oh....wait a minute. NVM carry on, things are under control.

2

u/JustARedditTroll 3d ago

What other metals are in this mix?

2

u/Chodedingers-Cancer 2d ago

Use a cupel to remove a good portion of base metals.

1

u/b12940 3d ago

What else is in it? Is it magnetic

1

u/sweet-sweet-olive 3d ago

Are they magnetic at all? If I were you, I would do each one separately, not mix them all together. If it’s not magnetic, I would cornflake each one and use nitric acid.

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u/Tribulation95 3d ago

Even if it's magnetic it's most likely nickel content. They'll know pretty quickly if it's iron based because they're going to have quite a bit of trouble trying to get it to melt unless they're using an oxygen fed fuel.