FIRE ASSAY CRUCIBLES are used to prepare the lead button, including the precious metal sample, for cupellation. These crucibles combine a high mechanical strength and erosion resistance with an ability to withstand severe thermal shocks from the assay furnace. The inclusion of fused silica in the mix enhances the TSR.
SCORIFIERS perform the same function, removing the gangue, but without using a furnace.
During cupellation the lead is oxidized to litharge (PbO), most of which is absorbed by the CUPEL, leaving at the finish a bead of gold, silver, and most of the platinum and associated precious metals that may be present. The cupels supplied are made from magnesite with a controlled pore structure for rapid absorption of litharge leaving an easily-removed bead.
Liling xing tai long special ceramic co.,ltd . Ms Tina 0086-13975373459