Litharge substitute home assay

[whsnare]

What can be used in the place of litharge in an assay?

 

[qst42know]

As I understand it bismuth can be used but I have never tried it.

 

[Anonymous]

Bismuth oxide may be used but it is extremely expensive.
"Normal" litharge contains lead oxide.In a closed oven/furnce this would be mixed with flour.The flour has no oxygen in order to burn so steals it from the lead oxide,turning it into elemental lead that is used as a collector for superfine gold,and helps drag it down out of suspension.Of course the lead will have to be cupelled,after the slag is removed,to recover the values.

 

[whsnare]

Bismuth oxide may be used but it is extremely expensive.
"Normal" litharge contains lead oxide.In a closed oven/furnce this would be mixed with flour.The flour has no oxygen in order to burn so steals it from the lead oxide,turning it into elemental lead that is used as a collector for superfine gold,and helps drag it down out of suspension.Of course the lead will have to be cupelled,after the slag is removed,to recover the values.

Would the Bismuth Oxide need to be cupelled as well?

 

[Anonymous]

Bismuth oxide may be used but it is extremely expensive.
"Normal" litharge contains lead oxide.In a closed oven/furnce this would be mixed with flour.The flour has no oxygen in order to burn so steals it from the lead oxide,turning it into elemental lead that is used as a collector for superfine gold,and helps drag it down out of suspension.Of course the lead will have to be cupelled,after the slag is removed,to recover the values.

Would the Bismuth Oxide need to be cupelled as well?

Bismuth oxide is a powder.You mean elemental bismuth.And I have no experience recovering values from a bismuth based button.....however You could just soak it in 50/50 nitric to dissolve the bismuth,leaving the PM's behind.

 

[Cody Reeder]

bismith will oxidise in a cupell but lead works best. I make my own litherage by heating some lead to arround 1200deg in an oxidising atmosphere. doing this will form a yellow litharge but I dont see any difrence with assaying except that the ratios of flower to lead are different, but I usualy add too much carbon anyway.

 

[Anonymous]

bismith will oxidise in a cupell but lead works best.

Bismuth is capable of oxidizing in any location,the cupel has nothing to do with it oxidizing.

 

[qst42know]

Cupelation is a combination of both absorption and oxidation.

The oxide is reduced by the carbon source to metallic which collects your values. And when the carbon is consumed the oxidation begins carrying with it the base metals. This can often be done in the same cupel all at once with some special exceptions.

 

[Anonymous]

Cupelation is a combination of both absorption and oxidation.

I was pointing reference to the comment that Cody made.Bismuth or,any base metal for that matter,need not be in a cupel to oxidize.Whether oxidation assists in the absorption of the bismuth(or lead),into the cupel was not my point.

 

[jsargent]

Bismuth oxide works fine. I have used it countless times. Metallic bismuth finely crushed and sifted say to -30 mesh works just fine too. The only problem in using bismuth is cleaning the button prior to cuppeling. It's tedious to scrape off the adhering flux. But it's worth it. very low toxicity.