Is purple precipitate a good sign?

[zamistroe]

I cornflaked a couple ounce lump of the mixed metal from my attempts at fire assay. Source was plated pins and ICs. I boiled it in sulfuric with potassium nitrate. Everything dissolved and precipitated into a purple or lavender layer. I know there's at least a little gold, but the lump was mostly copper and lead. Do I understand correctly that purple means gold? My SMB arrives in a few days. What should I do with it in the meantime?

 

[Yggdrasil]

I cornflaked a couple ounce lump of the mixed metal from my attempts at fire assay. Source was plated pins and ICs. I boiled it in sulfuric with potassium nitrate. Everything dissolved and precipitated into a purple or lavender layer. I know there's at least a little gold, but the lump was mostly copper and lead. Do I understand correctly that purple means gold? My SMB arrives in a few days. What should I do with it in the meantime?

Plated pins do not contain much Gold at all.
ICs may contain a fair bit depending on style and age.
Can you describe in more detail how it was treated first?
And why did you do a fire assay on such material in the first place?
The purple layer is probably micron sized Gold and needs to be dissolved once more and precipitated.
Siphon off as much liquid as you can and then cover the remains in HCl, then add a drop or more with bleach.
The purple should disappear immediately as it is dissolved.
Filter the solution well and set aside.
Then you can attack the rest of the solids, as I expect that there are more solids in the beaker??

So while you wait for your SMB I'd suggest you start doing some studies.


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[zamistroe]

I was trying something I saw in a video. The guy mixes his material with borax, lye, oxidizer, and collector metal then melts it down. The molten charge is poured into an upside down pyramid shaped mold. The metal, being heaviest, collects at the tip. Remove cooled casting and break off said tip. Then onto cupellation. Place metal blob in bone ash cupel or a formed mass of Portland cement and heat. As it melts, the more reactive base metal oxidizes and absorbs into cupel.

In my experience, some metal (the most reactive?) did as expected, but not all and not copper. I'd end up with 'brass' that looked like gold, but I knew I couldn't possibly have that much gold in the material. If I pushed it, with more heat and more time, EVERYTHING soaked into the damn cupel! In the video the guy put his lump into the cupel and into a kiln and came back to a little bead of Au & Ag. He even showed how when the last of the base metal left the remaining PM would 'blink', a momentary increase in brightness then the PM bead would be still.

I failed to recreate this, so I've gathered everything back into a blob, made cornflakes, and boiled in makeshift nitric. By adding HCl and bleach I'll be turning this into aqua regia, more or less? Everything goes into solution, no more precipitate, right? If I understand correctly, then I kill the acid with urea, and precipitate the gold with SMB. Does it really just grab gold out of a solution that has 4 or 5 (maybe more) metals dissolved?

Thank you for the link to Hoke and the others.

 

[Yggdrasil]

I was trying something I saw in a video. The guy mixes his material with borax, lye, oxidizer, and collector metal then melts it down. The molten charge is poured into an upside down pyramid shaped mold. The metal, being heaviest, collects at the tip. Remove cooled casting and break off said tip. Then onto cupellation. Place metal blob in bone ash cupel or a formed mass of Portland cement and heat. As it melts, the more reactive base metal oxidizes and absorbs into cupel.

In my experience, some metal (the most reactive?) did as expected, but not all and not copper. I'd end up with 'brass' that looked like gold, but I knew I couldn't possibly have that much gold in the material. If I pushed it, with more heat and more time, EVERYTHING soaked into the damn cupel! In the video the guy put his lump into the cupel and into a kiln and came back to a little bead of Au & Ag. He even showed how when the last of the base metal left the remaining PM would 'blink', a momentary increase in brightness then the PM bead would be still.

I failed to recreate this, so I've gathered everything back into a blob, made cornflakes, and boiled in makeshift nitric. By adding HCl and bleach I'll be turning this into aqua regia, more or less? Everything goes into solution, no more precipitate, right? If I understand correctly, then I kill the acid with urea, and precipitate the gold with SMB. Does it really just grab gold out of a solution that has 4 or 5 (maybe more) metals dissolved?

Thank you for the link to Hoke and the others.

This is the school example to not listening to Youtube videos until you understand what is going on.
The video itself may or may not be goodish but you interpret it wrong or the video may be downright dangerous.
Anything from Sreetips, Owltech and a few others are good the rest may be downright harakiri.

No and No.
HCl and bleach is not AR.
The problem about HCl and bleach is that it is an balancing act between getting enough Chlorine in the liquid and getting to much Sodium Hydroxide which will neutralize the Acid and stop it from working.
For Cupeling it need enough Lead and it needs to be at the correct temperature in a sufficient amount of time.
I suggest you go back to the drawing board and study much more.

 

[Yggdrasil]

I was trying something I saw in a video. The guy mixes his material with borax, lye, oxidizer, and collector metal then melts it down. The molten charge is poured into an upside down pyramid shaped mold. The metal, being heaviest, collects at the tip. Remove cooled casting and break off said tip. Then onto cupellation. Place metal blob in bone ash cupel or a formed mass of Portland cement and heat. As it melts, the more reactive base metal oxidizes and absorbs into cupel.

In my experience, some metal (the most reactive?) did as expected, but not all and not copper. I'd end up with 'brass' that looked like gold, but I knew I couldn't possibly have that much gold in the material. If I pushed it, with more heat and more time, EVERYTHING soaked into the damn cupel! In the video the guy put his lump into the cupel and into a kiln and came back to a little bead of Au & Ag. He even showed how when the last of the base metal left the remaining PM would 'blink', a momentary increase in brightness then the PM bead would be still.

I failed to recreate this, so I've gathered everything back into a blob, made cornflakes, and boiled in makeshift nitric. By adding HCl and bleach I'll be turning this into aqua regia, more or less? Everything goes into solution, no more precipitate, right? If I understand correctly, then I kill the acid with urea, and precipitate the gold with SMB. Does it really just grab gold out of a solution that has 4 or 5 (maybe more) metals dissolved?

Thank you for the link to Hoke and the others.

Before you try anything else lay out a plan and we will guide you on the way.
The pH indicate you have used way too much bleach.

 

[zamistroe]

Not a Sreetips fan, eh? What are his biggest faults would you say?

I wasn't clear. I haven't added HCl or bleach yet. Haven't done anything since starting this thread except pour into graduated cylinders to get a better look. See pics.

What I was asking: If I add HCl to my "poor man's nitric" it becomes "poor man's AR", right? Low quality copy of the real thing, but serviceable. If so, if strong enough, that lavender stuff should go into solution with the blue stuff. Then, if I haven't messed up somewhere else denox with urea (correct use of word?), stannous test, then SMB. Sound about right?

Again my SMB question: Does it really just grab the gold out of a multi metal solution?

Thanks again and please let me know if some other picture would help.

 

[Yggdrasil]

Not a Sreetips fan, eh? What are his biggest faults would you say?

I wasn't clear. I haven't added HCl or bleach yet. Haven't done anything since starting this thread except pour into graduated cylinders to get a better look. See pics.

What I was asking: If I add HCl to my "poor man's nitric" it becomes "poor man's AR", right? Low quality copy of the real thing, but serviceable. If so, if strong enough, that lavender stuff should go into solution with the blue stuff. Then, if I haven't messed up somewhere else denox with urea (correct use of word?), stannous test, then SMB. Sound about right?

Again my SMB question: Does it really just grab the gold out of a multi metal solution?

Thanks again and please View attachment 66034View attachment 66035let me know if some other picture would help.

Read me again!
Sreetips is one of the youtubers that can be trusted, he is a member here under a different name.
What you have here is the dreaded Metastannic acid.
Nitric and Tin.
It is a nightmare to filter so your option now is to dry it out roast it and dissolve it in HCl.

How did you obtain such a high pH without adding a alkali like Sodium Hydroxide?

No do not add HCl until after it has been dried and roasted to a dull red for some time.
We do no use Urea anymore we use Sulfamic acid.
Both SMB Ferrous Sulfate, Ascorbic acid and more will drop the Gold as long as the solution is acidic enough.
For dirty Solutions many prefer Ferrous Sulfate.

 

[zamistroe]

Roasting now. No bleach or lye at all. Thoughts on where the alkali came from? I don’t know. You can tell it's alkaline because it formed the metastannic?

 

[Yggdrasil]

Roasting now. No bleach or lye at all. Thoughts on where the alkali came from? I don’t know. You can tell it's alkaline because it formed the metastannic?

No. Because you used poormans Nitric and the metastannic formed.
That is what happens when Tin meets Nitric.

 

[Yggdrasil]

Roasting now. No bleach or lye at all. Thoughts on where the alkali came from? I don’t know. You can tell it's alkaline because it formed the metastannic?

How is your studies going?