How long will take for a cupellation to get finish? Is there any way to understand that the Pb got completely removed from the dore beads.( Au)
I start to run corrected fire assay since last February. But for last three days proof samples showing high retention value. Generally, we are using two proofs for ten samples and those proofs are loaded diagonal corner each other ie 1& 12. The problem am facing right now is that, if the first proof shows the value -0.560 and the second proof shows value -0.102. Temp we are doing FA is 1050 degree Celsius and the duration is 25 minutes. I never let those cupel inside the furnace after 25 min. However i remove them and tap on the side of the cupel in order to happen the BLICK.
I could see, after removing the cupel from the muffle, dense fumes coming from the dore beads, but after tapping on the side of the cupel, blick happened and those fumes disappeared. What does those dense fumes mean? are they Pb or something. Does it mean that high retention value on the proof sample due to those suppressed dense fumes. How could i tackle this tricky situation.
We are using this algorithm to calculate proof sample;
sample taken - weight obtained
For eg A B
140.232 140.723 A = proof sample
B = proof sample after parting, cornet value.
I start to run corrected fire assay since last February. But for last three days proof samples showing high retention value. Generally, we are using two proofs for ten samples and those proofs are loaded diagonal corner each other ie 1& 12. The problem am facing right now is that, if the first proof shows the value -0.560 and the second proof shows value -0.102. Temp we are doing FA is 1050 degree Celsius and the duration is 25 minutes. I never let those cupel inside the furnace after 25 min. However i remove them and tap on the side of the cupel in order to happen the BLICK.
I could see, after removing the cupel from the muffle, dense fumes coming from the dore beads, but after tapping on the side of the cupel, blick happened and those fumes disappeared. What does those dense fumes mean? are they Pb or something. Does it mean that high retention value on the proof sample due to those suppressed dense fumes. How could i tackle this tricky situation.
We are using this algorithm to calculate proof sample;
sample taken - weight obtained
For eg A B
140.232 140.723 A = proof sample
B = proof sample after parting, cornet value.