Alloy nugget refining process needed

[Stool]

Hello all,
I've been finding native alloy nuggets that contain gold, silver, iridium, ruthenium, palladium, platinum, copper iron, and zinc. I know it seems like a lot...
Is there a way I can remove the ferrous metals only and precipitate everything else or is this something I'm going to need to send to a refiner?

 

[jimdoc]

I think an assay to prove if those XRF numbers are correct would be a smart first step.

 

[anachronism]

Most of those readings are spurious.

Put a copper plate behind the items before taking the next readings and show us the results.

 

[Stool]

Don't take the percentages too literally. I've had 3 seperate xray assays done and the differences between them is pretty big. The same metals do show up on all of them though. Realistically I'm expecting 20% precious metal content, 60% iron, 20% other.

 

[FrugalRefiner]

May we see these nuggets, not just the XRF screen?

Dave

 

[Stool]

Best picture I can get. They have a slight copper colored tarnish that comes off fairly easily.

 

[anachronism]

Don't take the percentages too literally. I've had 3 seperate xray assays done and the differences between them is pretty big. The same metals do show up on all of them though. Realistically I'm expecting 20% precious metal content, 60% iron, 20% other.

I'd ask how do you know that you are expecting these figures? I'd also suggest that you try what I said and see what happens. I use a similar gun to yours so I'm not just guessing. 8)

 

[Justincase]

Don't take the percentages too literally. I've had 3 seperate xray assays done and the differences between them is pretty big. The same metals do show up on all of them though. Realistically I'm expecting 20% precious metal content, 60% iron, 20% other.

At only 20% noble metals I would just try a straight base metal leach.
That will show you how much may be value, and would be the first step to liberating it.
But I hate to have to repeat this sites Reson-Detra but, Have your finished reading Ms Hoke Yet?

 

[4metals]

Weigh a nugget and add 3 times its weight in silver to it and melt it together, make sure it is molten and becomes a well mixed bead before you remove the heat. Then hammer it flat and dissolve in 2 parts distilled water and 1 part nitric acid. Basically a crude fire assay. Hammering it flat just gives you more surface area for the acid to work, and will bust off any slags if you had to use a pinch of borax to melt it.

After the acid stops working decant off the acid and what remains will be your PM's. Iron and copper and silver will dissolve in the nitric (if the nitric is too strong the iron will passivate and not dissolve) Anyway this is a simple test and if when you're done there is nothing in the acid you know a little more about the spurious readings Jon referred to. Depending on their concentration in the original piece, palladium and platinum may dissolve as well, but the gold will remain and if it is there after the digestion, come back and we can give you options.

Ideally use enough so you can actually collect and melt what is left over, then you can use your XRF to get an idea of content.

 

[Stool]

The xrf gun isn't mine. Its at a recycling center that accepts palladium and platinum from catalytic converters. Its an hour away and $3 an assay and hard to get based on there hours and my schedules.
I had 3 seperate pieces assayed. The results were similar for gold and silver on all 3. There were huge differences in the pgm's and iron counts. The worst piece was 70% iron and 15% precious.
I would expect some differences on each piece but it seems a bit on the extreme. I have found a place that does fire assays and think I'm going to get everything double checked

 

[mausolfe]

Simple solution.

1. crush

2. setup quartz working tube

3. place powder in quartz boat

4. heat to several hundred degrees

5. pass 5% H2 diluted in Ar to reduce all metals.

6. chlorinate with HCl at same temp

7. only base metals will become chlorides

8. put into water at pH 2 HCl, only base metals will enter solution

9. centrifuge remaining metals

10. metals will be pgms.

For purification, repeat without hydrogen and use Cl2 gas in a sealed tube, quartz, and the use chromatographic methods to separate group elements.

See ya

EM, PhD

 

[g_axelsson]

Simple solution.

1. crush

2. setup quartz working tube

3. place powder in quartz boat

4. heat to several hundred degrees

5. pass 5% H2 diluted in Ar to reduce all metals.

6. chlorinate with HCl at same temp

7. only base metals will become chlorides

8. put into water at pH 2 HCl, only base metals will enter solution

9. centrifuge remaining metals

10. metals will be pgms.

For purification, repeat without hydrogen and use Cl2 gas in a sealed tube, quartz, and the use chromatographic methods to separate group elements.

See ya

EM, PhD

If that is a simple solution then I don't want to know what a hard solution looks like.

A post like this only proves two things...

1. You haven't done any professional refining, at the most you have theoretical knowledge.

2. This is not meant to help the original poster, it's just showing off.

Maybe you have a PhD or maybe you don't. We don't care. On this site experience is all and it is proved by posting useful answers or insightful questions.

By the way, I suspect that your simple solution have three major flaws.
1. It isn't easy to crush an alloy like that into a powder.
2. Silver chlorides will not dissolve in pH 2 HCl and it stays with the precious metals.
3. With an alloy of more than 50% precious metals the alloy will not separate into different metal grains, it will remain an alloy. Centrifuging the remaining precious metal powder is just extracting alloy from any liquid and that is not refining.

Göran

 

[Topher_osAUrus]

If that is a simple solution then I don't want to know what a hard solution looks like..
Göran

Isnt there more problems than that Göran?

Like pass H2 dilute in Ar to reduce metals?
-arent they already reduced? They are nuggets...
Or did he mean dilute in air?
Either way, the metal nuggets are metalic nuggets, not metal salt chunks.

Chlorinate with HCl, isn't that generally done with gaseous chlorine, or another method, like the HCl +bleach method, which liberates chlorine from the HCl?
Or would the "heat to a few hundred degrees" (centigrade, or Fahrenheit, dear doctor?) Actually make the HCl do some magic?

As you mentioned, its already way off base, and impractical to say the least...but, I was just curious if there was something Ive been missing.. . :roll:

 

[4metals]

5. pass 5% H2 diluted in Ar to reduce all metals

Hydrogen gas in Argon. This isn't an everyday backyard technique.

 

[g_axelsson]

There are a lot of problems I guess. I didn't have time to dissect the post any more and never felt a need to point out more problem. That's why I said "major flaws".

Yeah, most of the metals are already in metallic (reduced) state, but iron might be oxidized during "crushing" and also present as inclusions in a nugget. Hydrogen is an effective reducer at high temperature so in a quartz tube furnace it can be used to turn oxides into metals.
The next step would be to turn metals into chlorides with HCl as a gas. "At same temperature", but the temperature isn't specified. A lot of chlorides are volatile, including gold and silver chloride. Maybe HCl at high temperature (unspecified) only reacts with base metals, I don't know.

Dilute in Ar means dilute in argon, an inert gas so there is no oxygen present.

The "simple" procedure requires
- Temperature controlled tube furnace with a quartz tube
- A source of hydrogen gas
- Argon gas
- HCl gas (yes, you can get it in pure gas form)
- A centrifuge
And at this stage we haven't even refined the precious metals and for example any quartz in the nugget will still be there. Then he gives a very sketchy method for refining and separating the metals.
- Chlorine gas
- Use "chromatographic methods" to separate the precious metals, whatever that means

This "simple method" is as close to technobabble as you can get and not the least helpful.
https://en.wikipedia.org/wiki/Technobabble

Göran

 

[Platdigger]

Those are some strange nuggets for sure. What Country were they found in?

 

[anachronism]

Those are some strange nuggets for sure. What Country were they found in?

If they are nuggets then I would suggest Narnia.

 

[Platdigger]

Or Tim Buck Three maybe.

 

[rickbb]

Odd how some of them have a flat bottom. Looks more like poured shot or flake.

 

[mausolfe]

I’m pretty sure it works. For those of you saying it doesn’t. I spent the later portion of a year validating what I told you (process wise) from some dirt off of a volcano.

Results seem appropriate to me.