Where did the gold go?

[Kasse]

Update.
Flux mix I am.using. all measurements in grams.

1200 soda ash
700 borax
700 silica
200 red lead oxide
200 white flour
250 potassium nitrate

Results:
100gr sample of the #1 cons off the shaker table
200 gr flux
300gr iron bar

Recovery of 40gr mat layer
16 gr lead button.
60gr iron bar

The mat layer is slightly fused to the button, but breaks clean from it.

I keep adding more more oxidizer to reduce mat. Mat has not changed. Resmelt just the mat in the flux charge and it returns each time.
I have ran 15 samples all have a mat.
Gold recovery from the last 100gr sample was 40gr mat with 16gr lead button.
The button cuppel recovered. 0.136gr gold bead. With the 40gr mat layer remaining.
A question I have, would adding sodium nitrate as a second oxidizer help? Silica is good as the crucible is not being dissolved.

I have not roasted the con's yet. Tomorrow doing a nitric acid bath on a 100gr sample to see if it will dissolve the possible Telluride's in the sample.

Any ideas would be helpful.

 

[Kasse]

In fairness, gold going black in water would have set off a few alarm bells.

It did for me too. But it melted into a bright gold bead in a dish. No smoke or colored flame. It weighted 1.8 grams. I put the bead in a cuppel with so lead to pull some base metals out of it. Watched it melt and start oxidizing. Let it do its thing. Checked 30 min later and it was gone. Nothing left in the cuppel.

 

[Yggdrasil]

It did for me too. But it melted into a bright gold bead in a dish. No smoke or colored flame. It weighted 1.8 grams. I put the bead in a cuppel with so lead to pull some base metals out of it. Watched it melt and start oxidizing. Let it do its thing. Checked 30 min later and it was gone. Nothing left in the cuppel.

That means it was not Gold or vastly overheated or something else completely out of range.
As per my understanding you used too little Lead.

 

[Kasse]

That means it was not Gold or vastly overheated or something else completely out of range.
As per my understanding you used too little Lead.

I have Telluride's in my ore.

 

[Kasse]

Here is a photo of the mat and buttons

 

[Shark]

I know very little about ores but that picture is worth mentioning. If all pictures of ores were that clear it could help identifying what they are easier.

 

[Yggdrasil]

I have Telluride's in my ore.

Will Tellurides drag Gold with it?

 

[goldshark]

A 40 element ICP test may show what you are dealing with. I am also wondering if there is possibly some Manganese presence. The metal turning black in water is suspicious. Is it distilled , or chlorinated tap water?

 

[Kasse]

Will Tellurides drag Gold with it?

Yes

 

[Kasse]

A 40 element ICP test may show what you are dealing with. I am also wondering if there is possibly some Manganese presence. The metal turning black in water is suspicious. Is it distilled , or chlorinated tap water?

Well water from a natural spring.

 

[goldshark]

Well water from a natural spring.

There are a lot of minerals in well water, so still hard to say what is causing the discoloration. Distilled water should always be used in the lab, just for this reason.

 

[Yggdrasil]

Yes

Then you can obviously not cupel it.
You will need to get rid of the Tellurides first.