cupel


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cupel

[′kyü·pel]
(metallurgy)
A cup made of bone ash or magnesite, used in assaying precious metals.
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References in periodicals archive ?
The most important characteristic of his kit is the silver-assay scale and the cupel mold with three hollow hemispheres, and his balance that attached to the lamp holder.
During cupellation, a large part of the lead and of the impurities such as copper, tin and other metals are oxidised and partly vapourised, partly absorbed into the pores of the cupel. The resulting bead, consisting of precious metals only, is weighed.
The development of a pyrometallurgical process for the recovery of lead oxide from the cupels used in the fire assaying of precious metals is described.