Supply of air at the time of oxidation



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Is there any relationship between the amount of air supplied at the time of cupellation and the retention of base metals on the check. Why am asking this because last time, accidentally, i got increased the blower, which supply oxygen at the time of oxidation, and ended in high retention on the check sample; 0.9979 for the first proof and 0.9985 for the second proof. After that i regulated the air flow to a low limit, this time check showed high loss. How could i tackle this kind of tricky situation at the time of cupellation.


The most important things are:
1) make sure you have "enough" air introduced into the furnace to supply the oxygen needed to convert the Pb to PbO.
2) make sure your airflow is very consistent. You will have different losses and credits of the various metals with different airflows.
3) always run a proof. Adjust your results according to the losses and credits shown in the proof.


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What is the acceptable grade of blank samples submitted by mining companies in grams per ton? A consultant told me one can get 0.08g/t in salt water ?
The acceptable grade of a "blank" will be a factor of what value is significant to the type of sample you are running. So, a blank being submitted along with a concentrate may possibly have a higher value than a blank submitted along with a low grade ore sample.

Typically, blanks submitted with ore samples would have a gold concentration of about 0.002g/t (grams/metric tonne) or 0.002 ppm.