What kind of metal

[67eod]

Hi, I have run into a metal from processing CPUs and some gold nuggets from Alaska that does not desolve in AR. I have heated iAR to boiling and even tried different strengths. I have also tried straight nitric, AP and straight Muratic. It is light gold colored but turns black in all of the solutions.
I have beat as thin as a piece of paper and it tends to fracture when it get real thin.
:?:
Bob Noble

 

[markqf1]

Test the black residue that accumulates on the surface for pm's with stannous.
There are very few metals that resist the attack of boiling AR.
Maybe pgm's or alloy thereof.

Mark

 

[Harold_V]

Not suggesting it's the problem, but if your alloy has excessive silver, it won't dissolve in AR in spite of prolonged boiling. May I suggest you give the material a go at dilute nitric first? If silver is the problem, it will be evident almost immediately.

If you choose to give this a try, don't use material that has already been exposed to AR. Start with something that hasn't. The exposed material, assuming the problem is caused by silver, won't react with nitric either, the hard shell having formed preventing the acid from reaching the intended target.

Harold

 

[Richard36]

Not suggesting it's the problem, but if your alloy has excessive silver, it won't dissolve in AR in spite of prolonged boiling. May I suggest you give the material a go at dilute nitric first? If silver is the problem, it will be evident almost immediately.

If you choose to give this a try, don't use material that has already been exposed to AR. Start with something that hasn't. The exposed material, assuming the problem is caused by silver, won't react with nitric either, the hard shell having formed preventing the acid from reaching the intended target.

Harold

Hello Harold,

Long time no talk!

From all that I have read, If it was silver that were the problem, it should have become coated with a white coating of silver chloride due to the chlorine in the AR, or HCL reacting with the silver to create silver chloride, if high in silver, however, I do understand that low concentrations of silver in gold will cause gold to turn black in nitric. I am not sure about the issue with the gold from scrap, but the gold nuggets may well be an alloy of whatever those black to silver colored spheres are that GSP and I found that are being disscussed by me and others in one of the other threads, I think it was under "The Rock Man". Anyway, I thought that maybe they were some type of Rare Earth metal. I do not know much about the solubility characteristics of Rare Earths, But those spheres react the same way. If indeed they are some type of Rare Earth, maybe Bob's gold is alloyed with some one or more of the Rare Earth metals, and that is part of the problem that he is having.

Just a thought.

Sincerely; Rick.

 

[67eod]

Hi,
I have remelted the metal several times to try different solutions. I beat it flat and thin to get more surface area exposed to the chem,s all with the same results. I have tried the weak nitric and the strong with the same results. At this point I have a about 15 grams of the stuff. It does not act like any of the silver alloys I have run into. I have been using butyl dimethyline to extract my gold from AR and Hl and clorex solutions with good results, but this stuff started to show up on the clean up filters and its got me stumped. I have been selling my gold to Midwest and have been toying with the idea of sending some to them and see what they say.

Bob :?:

 

[markqf1]

How hot did you have to get it to melt it ?
Specific gravity could help identify it.
Have you tried a boil in concentrated h2so4?

Mark

 

[Rhodium]

This is interesting. http://www.kingsbaygold.com/site/exploration/bobjo/p2-bobjo.htm#

 

[Rhodium]

:arrow:

 

[Richard36]

Hello Rhodium.

Thanks for the PDF.
Any further info that you could provide on this subjuct would be greatly appreciated.

Thanks again.

Sincerely; Rick.

 

[Rhodium]

I'm digging.

 

[Richard36]

I'm digging.

Thanks!
I will be watching this thread closely for further info on the Rare Earth metals.

Thanks again!

Sincerely; Rick.

 

[Rhodium]

.

 

[Richard36]

Thanks Rhodium.

I will be reading those!
I appreciate your help, Greatly!

Thanks again!

Sincerely; Rick.

 

[Harold_V]

From all that I have read, If it was silver that were the problem, it should have become coated with a white coating of silver chloride due to the chlorine in the AR,

It was my experience that if there was enough silver to stop dissolution, you didn't get the familiar white silver chloride, but, instead, a greenish gray deposit formed, likely due to the interaction of the dissolved gold with the silver chloride that was slowly created on the surface. This deposit quickly becomes impervious, unlike the white deposit that develops and sheds easily. The percentage of silver that is present dictates which way it goes. It is for this reason that 4metals has talked of selectively melting gold alloys by the "big boys", who do not use inquartation in processing karat gold.

Looks like, at least in this instance, that's not what's happening, however. It was just a shot in the dark.

Harold

An after thought. It is a commonly held belief that many of the platinum metals are on this planet as a result of impacts with earth by other bodies. I wonder----could those spheres be the result of just such an occurrence? Perhaps even related to the extinction of the dinosaur?

 

[g_axelsson]

If this is an alloy of various metals and it is causing a lot of troubles, why not just inquart it with some silver and then treat it with nitric acid. After that all the gold will be exposed and can be dissolved with AR. If there is something that isn't dissolving in nitric or AR then it will be left after the gold is removed.

The platinum group metals as well as gold is more common in meteoritic material as it has a large affinity to molten iron. On Earth most of the precious metals are locked into our iron core. There are some reports that shows that as much as half of the precious metals on Earths surface is from meteorites that reached Earth after the crust had solidified. Iron meteorites usually have as much as a couple of grams gold per ton in them.

/Göran