*cupel*

pos>n. [ See Cupel. ] The act or process of refining gold or silver, etc., in a cupel. [ 1913 Webster ]

☞ The process consist in exposing the cupel containing the metal to be assayed or refined to a hot blast, by which the lead, copper, tin, etc., are oxidized, dissolved, and carried down into the porous cupel, leaving the unoxidizable precious metal. If lead is not already present in the alloy it must be added before cupellation. [ 1913 Webster ]