cupel
/ˈkjuːp(ə)l
/noun
A shallow, porous container in which gold or silver can be refined or assayed by melting with a blast of hot air which oxidizes lead or other base metals.On cooling, the prill is carefully extracted from the cupel....
- We produce several capacity crucibles and cupels and only use selected virgin materials for production.
- Absorption is facilitated by manufacture of the cupel from a porous material such as bone ash.
verb (cupels, cupelling, cupelled; US cupels, cupeling, cupeled) [with object]
Assay or refine (a metal) in a cupel: to extract the silver, the Greeks roasted the ore and then cupelled the molten metal...
- The product is then cupelled to increase the dross to the range of about 50-65% by weight bismuth.
- The lead button is cupelled to oxidize the lead leaving behind a dore bead containing the precious metals.
- Gold and silver bullion that remains in a cupelling furnace after the lead has been oxidized and skimmed off.
Derivatives
cupellation
/ noun ...- The lead alloy was then separated into its component metals by cupellation.
- In cupellation the lead button is again heated in a furnace at 960°C to 1000°C, but this time in a bone ash cup or cupel.
- No doubt the high silver content of Mendip lead was an important factor in its early exploitation, but we have no means of assessing either the total output of lead or of the amount of silver extracted from it by cupellation.
Origin
Early 17th century (as a noun): from French coupelle, diminutive of coupe 'goblet'.