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RikkiRicardo

Well-known member
Joined
Dec 1, 2008
Messages
142
Location
Romania
Hi
How would anyone process it's all metals Bismuth/copper/silver/gold/platinum there is nothing else in there
at this time i have put this into powder as it was solid
this is something i have not worked with i have done some small tests
and did stannous tests and it comes solid black on the Q tip


Rikki
 
Do you now percentages of each of these metals?
What is the source material from?
How did you "put this metal into a powder".
The percentages of each of these metals could be a determining factor of what I might choose as a process.
Example if mostly bismuth I might try a sample in a bone ash cupel first, or a flux melt, then part in HNO3, then aqua regia.


Although if you have it in powders already then going to acids could be easier at this point, instead of melting it back to metal.

Actually percentages of the metal if known would make it a little easier, as there may be other methods depending on what you have, and which way may work better than others.
 
Butcher
no i don't have the percentage I'm guessing 20% silver low on the copper 30% bismuth rest gold and platinum
i have done a test first with nitric then filtered and added hlc to recover silver then all the powder i did it in ar then i added zink to drop what metals i have in there
everything comes down black all i can tell you that it's a high percentage of black powder at this point
where the stuff comes from i would not know i have 450 kg to do now I'm wondering if some of the platinum went with the silver?
an how to check if it did.all my test to see what metals i have the q tip stays black black no mater how much metals drop i have been putting zink the filtering
and checking now it's starting to stay a bit clearer.

Rikki
 
Rikki if your estimates are right you have an awful lot of value sitting in that material, to be honest I doubt the gold and platinum will be that high but I could be wrong.
My view would be to remove the lower value materials first leaving the gold and platinum for later recovery and refining, by using nitric you may well dissolve some of the platinum and any other PGMs present along with the silver, coper and bismuth, if you used dilute sulphuric it would dissolve the silver, copper and bismuth leaving the gold and any PGMs as a residue. I suggest some small trials in a fume hood using both methods to see which is the best suited for your needs and which actually produces the results you need. By using sulphuric the residues left will be easily dissolved in AR and the gold can be precipitated from that solution and the PGMs cemented ready for either further refining or simply melting and the silver can be recovered easily enough from the sulphuric but would require further refining. The bismuth has a value I believe but I can't help much with its recovery it's beyond my experience but I'm assuming it's also probably recoverable for further processing by specialist refiners.
 
RikkiRicardo said:
Butcher
no i don't have the percentage I'm guessing 20% silver low on the copper 30% bismuth rest gold and platinum
i have done a test first with nitric then filtered and added hlc to recover silver then all the powder i did it in ar then i added zink to drop what metals i have in there
everything comes down black all i can tell you that it's a high percentage of black powder at this point
where the stuff comes from i would not know i have 450 kg to do now I'm wondering if some of the platinum went with the silver?
an how to check if it did.all my test to see what metals i have the q tip stays black black no mater how much metals drop i have been putting zink the filtering
and checking now it's starting to stay a bit clearer.

Rikki
Click to expand...

You can use a test sample and dilute it and possibly see the colors in your stannous test better.
 
According to your scheme the black powder
should contain the Pt and Au. I would try to
assess percentages of both
 
hello everyone I am a very big amateur when it comes to refining gold. I recently started to refine gold I used a mixture of hydrochloric acid and bleach to dissolve my gold from glass everything seemed to be going pretty well, I removed all the gold of my glassware and it was a nice looking solution of Auric chloride. at that time I decided to use my sodium metabisulfite. when I added it it did not seem to drop any gold it all just sank to the bottom and then nothing happened. After a couple days I took a little bit of out and it appeared to beat a little darker, but nothing that look like gold powder. when I added the sodium metabisulfite I did put in the suggested amount of 240 milliliters of water for 28 grams of smb. I was hoping that somebody could tell me what went wrong. I have been reading several forums and watching lot of videos and I still cannot figure this out. only thing I can come up with is that I may have used too much sodium metabisulfite or timing may have been too fast. please please please give me a clue. thank you very much
Never, never, never, never, give up
Click to expand...
Winston Churchill
 
Getting gold off of glass ware is very easy, the gold is very thin, so you have to have a lot of surface area to get much gold.

This could be the problem, not much gold dissolved, so there is not much gold to precipitate from solution. The little bit of powder could be all the gold you have.

Another thing is chlorine generated from the bleach in acid, is an oxidizer, as long as there is chlorine in solution you cannot reduce the gold back to the brown metal powder with SMB, the oxidizer will just redissolve your gold again, chlorine (if you did not add way too much) is easy to remove, it will form a gas with heat and leave the solution, in the summer letting it sit all day in the sun can work if you did not use too much, gas stays in a cold solution so in the winter heat is needed, this could also be the problem try heating the solution.

I do not know how much gold you dissolved, but you only need about as much SMB as gold you dissolved, it would probably take a couple of truck loads of good gold plated glass ware to get 28 grams of gold, so I suspect you added too much SMB, although you do not want to do this it should not cause too much harm at this point.

Did you do your stannous chloride testing, if not you are just working in the dark and will never know where you are going, you have no way of knowing where the gold is and where it is not...

But at this point I think you would get false positive brown even if there was no gold in solution because I suspect overuse of SMB.
Do a stannous chloride test on a Q-tip see what color, if you cannot tell hold the Q-tip in the vapors where you are heating your solution to drive off chlorine from your gold solution, the chlorine or acid vapors will lighten the color from black to violet if positive for gold, or from brown to almost black to a light brown if too much SMB and no gold in solution.
 
Hi
this bismuth is a problem

nickvc i have tried the dilute sulfuric with heat then filter and still getting bismuth and yes there is gold/plat in this stuff
just the other day i had the stuff xrf an it showed this is after i dropped the metals with zink When you are talking about
diluted sulfuric what percentage should it be and how would i know that if i have removed it from the powder

i need the best way to remove the bismuth

Rikki
 
From Wikipedia:
Bismuth dissolves in concentrated sulfuric acid to make bismuth(III)sulfate and sulfur dioxide gas.
6 H2SO4 + 2 Bi → 6 H2O + Bi2(SO4)3 + 3 SO2
Bismuth reacts with nitric acid to make bismuth(III) nitrate.
Bi + 6 HNO3 → 3 H2O + 3 NO2 + Bi(NO3)3
Bismuth also dissolves in hydrochloric acid, but only with oxygen present.
4 Bi + 3 O2 + 12 HCl → 4 BiCl3 + 6 H2O



Bismuth melts at around 270 degrees but can be mixed with other metals to form very low melting point metals, some that can be melted at temperatures used to make coffee, these bismuth amalgams of low melting metals have uses for things like fire links and boiler safety plugs, or solder that can solder with a match.

When molten, at temperatures above 710 °C, bismuth can form trioxides, this oxide corrodes any metal to oxide, even platinum.

Bismuth has a very low melting point with gold it will lower golds melting point and can almagam with gold, silver or PGM and other metals.
Bismuth can be used instead of lead for the assay of gold and silver by cupellation, as the melted oxide is absorbed by bone ash in exactly the same manner as lead oxides litharge.


Depending on what you are working with bismuth can be cupelled, High temperature from an oxidizing environment Bismuth is oxidized and absorbed into a bone ash cupel, like lead and some other metals will
 
Butcher
how would you go on this i want to remove the PM from this bismuth is the highest in metals
i need to recover the PM but the bismuth is giving me problems
Rikki
 
Guessing 20% silver low on the copper 30% bismuth rest gold and platinum

From what I understand so far this was a metal, and you put it in powder form.
(I still am not sure how you put it into powder form)
It sounds to me like you had an amalgam, possibly from a recovery process where they used bismuth to collect silver gold and platinum, if these were melted together with bismuth.
I like nickvc, think you probably do not have as high as a percentage of platinum as you may think at this point.
If I had this material I think the first thing (experiment) I would try would be a small sample in a bone ash cupel, using a torch with an oxidizing flame I would heat it up, raise heat to oxidize the bismuth and copper and then bring heat up so that the bone ash absorbed as much of the bismuth and copper oxides as possible, hoping for a small bead of silver gold and platinum, which I would try and separate with acid treatments.

I have done a test first with nitric then filtered and added HCl to recover silver.

The nitric would dissolve much the bismuth copper and silver, so I do not see a problem there as long as you used enough acid, platinum may try to follow the silver here I am not sure, if high silver in a melt with platinum it can, but this was probably not the case with the low temperature amalgam, the one problem I think I see here is using HCl to recover the silver back, as far as I know bismuth would also precipitate with your silver, from what I understand bismuth makes some very strange halide complexes, and bismuth chloride is insoluble, if any platinum did go into solution with the nitrates , you have formed a form of aqua regia when you added HCl to precipitate silver (it would have a high nitric content at this point, and low chloride, so I would save the solution to test it further for platinum, I would do this test on a small scale in a test tube, adding some more HCl to a few ml of the nitrate solution , add a drop of concentratedH2SO4, and heating the test tube in a sand bath to vapor off free nitric, vapor to syrup pipette a drop or two of HCl, vapor off and another couple of drops of HCl, vapor, cool dilute and test with stannous chloride looking for orange if platinum, violet if gold.

If you still cannot tell add a few drops of the solution to be tested to a spot plate, add a crystal of ferrous sulfate, if you see a brown ring of precipitated gold around the crystal there was gold in solution decant the clear liquid from this test to another well on the spot plate a pipette to move the liquid, now you have a solution free of gold you can retest with stannous chloride to see if it shows orange for platinum.

Your silver chloride and possible bismuth chloride, I would try to convert the silver chloride back to metal, (doing so would also convert the bismuth as far as I know). Then you could try several ways to separate these, like the cupel, or nitric acid and cementing silver from the bismuth in the nitrate solution by cementing with copper leaving the bismuth as a nitrate.
Copper is below bismuth in the reactivity series silver is below copper. (Read on goggle about the reactivity series of metal for a better understanding).


Then all the powder I did it in aqua regia, then I added zinc to drop what metals I have in there.

Aqua regia was not a bad choice, but the problem here is with using zinc is you just cemented back out all of the metals you dissolved, bismuth, copper silver, gold and platinum are below zinc in the reactivity series of metals, so any of these you dissolved you cemented back out of solution, by choosing zinc, (copper here would have been a better choice), (or using selective reagents, like ferrous sulfate for gold, ammonium chloride for platinum), (silver chloride you could of gotten from just diluting the denoxxed solution).
Again do a study the reactivity series of metals.

Everything comes down black all i can tell you that it's a high percentage of black powder at this point.

Yes, zinc cement it all back out, plus, now you may even have added a little zinc to the mix.

Where the stuff comes from I would not know I have 450 kg to do now I'm wondering if some of the platinum went with the silver?

Maybe see above

How to check if it did?

See above

All my test to see what metals i have the q tip stays black, black no mater how much metals drop I have been putting zinc the filtering.

Try the test above, and or diluting as was suggested.

And checking now it's starting to stay a bit clearer.

I am not sure what your talking about here.
 
Rikki as I said these are just ideas and they will be trial and error and as I have never treated this type of material myself so your just going to have to mess until you find the method that works for you.
With the sulphuric I'd be tempted to use dilute acids first to avoid boil overs, the metal digesting very fast creating heat and further faster dissolution and then maybe more concentrated acids to finish off the digestion, this may work but you are going to have to try it to find out.
Another thought that may be worth thinking about is using AR to digest most of the bismuth, this takes some skill and a lot of attention and testing with stannous, filtering and washing the remaining powders and then using nitric to remove he last of the bismuth. This will leave silver chloride and the gold and platinum again filter and wash and dissolve the remaining powder in AR, filter to remove silver chloride and then precipitate the gold filter again and then either cement the Pt or reduce with zinc dust. This method will almost certainly mean refining the obtained values further if you want pure metals and the silver chloride will almost certainly contain Pt and Au in small quantities. This method is not for the faint hearted and is very easy to get wrong until you get the hang of it so testing all solutions produced is essential. Costs can be another factor as can the equipment you have or will need to run this material in volume so it's trial time again Rikki. Good luck.
 
Butcher /Nickvc

Thanks for all your input this is my biggest challenge so far without this forum i would of been lost
as I'm not a chemist and i don't ask to many questions but when i do you guy's really help
this is what i love to do trial and error this is how i work this how we learn
but with you help i have only have great success this is to all you guy's that has help me and everyone on this forum
Thanks from all of us
i will have pictures of the stuff plus the output and what was the best process i felt work the best
again Thanks.

Rikki
 

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