assay question

[boulder dash]

Anyone have any assay experience? We have been doing a standard fire assay on our hard rock concentrates. When we have the lead that goes into the cuppel and is supposed to leave only your precious metals. We end up with a very dense heavy gray silver button. Out of a 30 gram assay we get 16-20 grams of this heavy metal. My question is what other metals will stay in a cuppel besides the precious metals gold,sliver, and platinum?

 

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[KevinInColorado]

I've done a few fire assays. Looks like lead (a likely partial cupel...maybe too cold in furnace or not enuf oxygen), how soft is it?

If soft, lead. If harder is it brittle (tin) or tough/bends a little...could be lots of metals I suppose.

 

[arizau]

I'm pretty sure the following is correct. Correct me if I'm wrong.

As I understand it, the bead formed is usually an alloy of several different metals and the appearance represents the comparative proportion of how much of each there was in the charged material. The gold content may be less proportionately than say copper, silver, or some combination of them and other metals that was contained in the ore. A true assay of that bead will determine the various proportionality of each metal eg. 80% Cu, 10% Ag, 5% Au and 5% other elements or whatever the different proportions are. I use this just as an example to illustrate what can happen.

 

[GrizzlyGremlin]

Yessir you did the assay now you need to refine, home your a chemically inclined person!!

 

[boulder dash]

Not lead we covered up a botton with lead and re did it it only lost 1/10 gram. Its a metal .

 

[KevinInColorado]

Take it to your local college for identification. Scanning electron microscope spectrography or other lab techniques will answer you well.

 

[jair]

I do fire assays also , but have never came out with any thing like that . If you have any more from a nother assay , try nitric on it , in a ventilated area. If it eats up fairly quickly , tin I would say .