Using ammonium chloride to 'remove' oxides

[Amol Gupta]

Reading across the forum I found references of using ammonium chloride to remove base metal oxides from refined gold.

The addition is always done as the gold is transitioning from the solid state to liquid or solidifying from liquid state to solid.

I was curious as to why is this done during the transition phase(solid to liquid and vis-a-vis) and not a steady state(when the gold is molten in the crucible).

Also my reading suggest this would only remove the base metal oxides, does it remove silver as well....?

 

[Yggdrasil]

Reading across the forum I found references of using ammonium chloride to remove base metal oxides from refined gold.

The addition is always done as the gold is transitioning from the solid state to liquid or solidifying from liquid state to solid.

I was curious as to why is this done during the transition phase(solid to liquid and vis-a-vis) and not a steady state(when the gold is molten in the crucible).

Also my reading suggest this would only remove the base metal oxides, does it remove silver as well....?

I think you misunderstood.
Ammonium Hydroxide can dissolve many things including Silver Chloride.
If you suspect Silver Chlorid it is essential to acidify as fast as possible after.
I have never heard that Ammonium Chloride can do this.

 

[Amol Gupta]

I think you misunderstood.
Ammonium Hydroxide can dissolve many things including Silver Chloride.
If you suspect Silver Chlorid it is essential to acidify as fast as possible after.
I have never heard that Ammonium Chloride can do this.

I'm talking of ammonium chloride being used as flux

 

[Yggdrasil]

I'm talking of ammonium chloride being used as flux

Never heard about that either.
I can’t quite see how the Chloride should be able to remove Oxides though.
Do you have a link?

 

[Amol Gupta]

Never heard about that either.
I can’t quite see how the Chloride should be able to remove Oxides though.
Do you have a link?

Post in thread 'Flux for Making a gold bar' https://goldrefiningforum.com/threads/flux-for-making-a-gold-bar.5416/post-46481

This for one along with many others.