Fire assay a pulverized cupel

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Dwf

Member
Joined
Jul 6, 2020
Messages
17
This is the first time I have ever tried this, to check for losses in the cupel.
I tried pulverizing the cupel to 100 mesh, and mixing it with 90g of legends fire assay flux with flour.
I let it sit in the furnace at 2000f for 40 minutes, then tried to pour with no success. It was a solid red hot mass in the crucible, and would not pour.
Not sure what went wrong?
Magnesia cupel btw.
 
Dwf said:
This is the first time I have ever tried this, to check for losses in the cupel.
I tried pulverizing the cupel to 100 mesh, and mixing it with 90g of legends fire assay flux with flour.
I let it sit in the furnace at 2000f for 40 minutes, then tried to pour with no success. It was a solid red hot mass in the crucible, and would not pour.
Not sure what went wrong?
Magnesia cupel btw.

I'm not an expert at smelting. But, you didn't mention your weight ratio of crushed cupels to the 90gms of flux. You probably would have better results using a Chapman-like flux rather than a assay flux. Also, did you use any collector metal in your crushed cupel/flux mix?

This company makes some very good mining equipment and the owner does alot of good vids regarding sampling via cupelling. He does one regarding recycling his used cupels (handmade/portland cement). However, be aware, his use of PPE and his other equipment is not admirable.

MBMLLC -
https://www.youtube.com/user/mbmmllc

Gold From Lost Lead Pt. 1: Lead, Gold, & Silver Recovered by Re-Smelting Cupels -
https://www.youtube.com/watch?v=QHY1K2_AODM

Peace and health,
James
 
https://link.springer.com/article/10.1007/s13404-013-0101-1

You should see that. Likely you do not need to do a fusion on the entire cupel, just the center.

But yes, it will be necessary to know how much your cupel weighs. Likely the amount of cupel used in relation to silica is too high.

Also, you may need to add more flour to counteract the oxidizing effect of the magnesia.


Sent from my iPhone using Tapatalk
 
snoman701 said:
https://link.springer.com/article/10.1007/s13404-013-0101-1

You should see that. Likely you do not need to do a fusion on the entire cupel, just the center.

But yes, it will be necessary to know how much your cupel weighs. Likely the amount of cupel used in relation to silica is too high.

Also, you may need to add more flour to counteract the oxidizing effect of the magnesia.


Sent from my iPhone using Tapatalk

Thanks, that was a very interesting read and better explained than any I have read so far.
 
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