Why did i got my gold button white ?

[razvanflorin]

Hello everybody ! I do have a misunderstanding.
I have melted some gold foils and I have got a gold button of 1,6 Grams.
- The gold button is white.
- After i have melted the gold button I have boiled it in Nitric Acid and he had became yellow. If i cut it, it is still white inside.
- After this I have remelted the gold button and he became back White..

Any idea or information ?

My idea is to directly boil the gold foils in nitric acid before melting.. :!: does this help ? :?:

 

[nickvc]

It's hard to give you a exact answer but I'd say you had lots of base metals and salts still with your foils.
In honesty when you have reached the foils stage you should have refined them as it's very easy to do with several methods available including HCl and bleach or HCl and peroxide, once dissolved filtered and precipitated you should have good quality gold to melt instead now you have a mess of metals and a hard time to dissolve it if it has formed a metallic button which you will now have to dissolve either in AR or poormans AR to get your gold clean..
Don't be too upset it's all a learning curve you just hoped you could miss out a step but have now learned you can't.

 

[Lou]

Nickel?

 

[razvanflorin]

It's hard to give you a exact answer but I'd say you had lots of base metals and salts still with your foils.
In honesty when you have reached the foils stage you should have refined them as it's very easy to do with several methods available including HCl and bleach or HCl and peroxide, once dissolved filtered and precipitated you should have good quality gold to melt instead now you have a mess of metals and a hard time to dissolve it if it has formed a metallic button which you will now have to dissolve either in AR or poormans AR to get your gold clean..
Don't be too upset it's all a learning curve you just hoped you could miss out a step but have now learned you can't.

I know about that but it's look too complicated for me, it's must be a trick somewhere to get a high purity by directly melting the foils, i say that because my uncle it's doing that and got buttons of 22-23 k but as i have mentioned in the previous topic, he didn't wanna' tell me how he do it.

my questions is that if i boil the foils in nitric it would help to get a bigger purity ?

Nickel?

I have to do an XRF Scan it's Nickel or Tin

 

[kernels]

If you have access to Nitric acid, then just refine your gold !!!!!!!

It's not complicated, the only reason some people don't do it is they don't have access to Nitric acid. With very basic single refining of only foils you will get 99 percent+ every time no sweat.

If you used the AP process to recover the foils, then it's not likely to be Tin or Nickel as the HCl happily attacks both. But really without doing an XRF it's hard to tell you an answer.

 

[jason_recliner]

my questions is that if i boil the foils in nitric it would help to get a bigger purity ?

In general, no. And there's no "trick" to getting high purity by melting foils. It just doesn't work that way. Foils are not pure gold, so you can't make them pure by melting them. If you have impure gold and you melt it into a button, you will have a molten, impure, gold button.

Instead, you need to refine it. Once you have your foils, you have not even STARTED refining. You've only completed the first stage of recovery. Only then can you even begin refining.
But take comfort knowing that you haven't lost any gold, as long as you don't throw anything away.

Where to from here? As usual, Nick's advice is spot on. As is Lou's suggestion that nickel is what's usually under foils, and therefore probably what is polluting your button.
Since you appear to have access to nitric, AR is probably your best way to refine your button. But you must add your nitric to HCl in VERY TINY AMOUNTS with plenty of PATIENCE, or you will find it impossible to precipitate the gold out of an excessively-nitric solution. Understand why this is true, before you begin. Otherwise you will end up in just another mess wondering what's happening.

 

[razvanflorin]

Well.. Thanks you everybody, i will try to refine it with AR, the only problem is that i didn't have SMB, from where can i get this ? :mrgreen:

Mmh.. I have some Sodium MonoBISULFATE in my depo, how can i reduce it from NaHSO4 TO NaHSO3 Does it is possible ?

 

[jason_recliner]

Try brewing shops, who sell it as a sterilising agent.

 

[upcyclist]

Try brewing shops, who sell it as a sterilising agent.

Or try copperas (Iron sulfate), also used in beer- and wine-making.