Lost gold when smelting

[OroMontalban]

Had small amount of microscopic gold that I wanted to change it into a solid mass instead of keeping it in a sample vial. I use equal amount of Chapman's flux and heated with acetylene and oxygen torch to my surprice when sample was melted I had no recovery at all other than a few spec's of gold between the crusible and and flux. By using Acetylene can the gold be evaporated due to high heat?
Thank you

 

[Alondro]

Can't smelt tiny amounts of gold well. The best bet there would have been just putting it in a melt dish with some borax, and then tilt the dish side to side to get the tiny beads to collect into one.

 

[Yggdrasil]

Had small amount of microscopic gold that I wanted to change it into a solid mass instead of keeping it in a sample vial. I use equal amount of Chapman's flux and heated with acetylene and oxygen torch to my surprice when sample was melted I had no recovery at all other than a few spec's of gold between the crusible and and flux. By using Acetylene can the gold be evaporated due to high heat?
Thank you

It is most likely still there but now it is embedded in the flux.
You did not use a collector metal, did you?
The slag was too thick to let the particles coalesce in the thick slag.
Most likely.

 

[OroMontalban]

Can't smelt tiny amounts of gold well. The best bet there would have been just putting it in a melt dish with some borax, and then tilt the dish side to side to get the tiny beads to collect into one.

Now I know
Thank you

 

[OroMontalban]

It is most likely still there but now it is embedded in the flux.
You did not use a collector metal, did you?
The slag was too thick to let the particles coalesce in the thick slag.
Most likely.

Yes it's in the flux and no I did not used a collector
Thank you
Best regards

 

[4metals]

@OroMontalban, If you had a powder before your melt attempt it is better for future refines to leave it as a powder and accumulate all of your dry powders from small refines before doing one last refine to boost the purity. If you do this the smaller particle size of the powders will greatly enhance the digestion rate and require less nitric acid.

 

[OroMontalban]

@OroMontalban, If you had a powder before your melt attempt it is better for future refines to leave it as a powder and accumulate all of your dry powders from small refines before doing one last refine to boost the purity. If you do this the smaller particle size of the powders will greatly enhance the digestion rate and require less nitric acid.

Yes, that is what I did i had 6 samples that I pull together but still it was a small sample my mistake was not to use a gold collector and the use of flux. Gold is still on the crusible later I will try to recover it, any suggestions to remove embedded gold in the flux. Will HCL plus heat release the gold from the flux in crusible?
Thank you

 

[4metals]

Yes, that is what I did i had 6 samples that I pull together but still it was a small sample my mistake was not to use a gold collector and the use of flux. Gold is still on the crusible later I will try to recover it, any suggestions to remove embedded gold in the flux. Will HCL plus heat release the gold from the flux in crusible?

I never recommend using any liquid to leach gold out of a crucible you plan to re use for. melting. Too much chance for a steam explosion.

Check out this thread and use more flux to melt your solidified flux.

 

[OroMontalban]

I never recommend using any liquid to leach gold out of a crucible you plan to re use for. melting. Too much chance for a steam explosion.

Check out this thread and use more flux to melt your solidified flux.

I'm glad I asked. The thread has a lot of information and specifically the safety issues that will most definitely will consider.
Thank you again
Best regards

 

[OroMontalban]

It is most likely still there but now it is embedded in the flux.
You did not use a collector metal, did you?
The slag was too thick to let the particles coalesce in the thick slag.
Most likely.

Can you please send me the thread on Waste Treatment and Disposal
Best regards

 

[SRM]

Depending upon the crucible, you might be able to reheat the slag. If the slag is too thick, use a thinner (sparingly, flux thinners are notorious for thinning crucibles) or add a collector metal (plumber's wool works well, make sure to weigh it before adding it to the smelt. If you go with a collector metal, you will have an additional step (cupellation) before you can see your gold.

 

[4metals]

Can you please send me the thread on Waste Treatment and Disposal
Best regards

Dealing with waste.

 

[OroMontalban]

Depending upon the crucible, you might be able to reheat the slag. If the slag is too thick, use a thinner (sparingly, flux thinners are notorious for thinning crucibles) or add a collector metal (plumber's wool works well, make sure to weigh it before adding it to the smelt. If you go with a collector metal, you will have an additional step (cupellation) before you can see your gold.

Thank you for your comment
Best regards

 

[OroMontalban]

Dealing with waste.

Thank you