Cupellation

enUK

cupellation

[‚kyü·pə′lā·shən] (metallurgy) Method using a cupel for assaying precious metals. Process for refining gold and silver by alloying them with lead and then oxidizing the molten lead to separate the base metal from the precious metal.

Cupellation

oxidation melting of an alloy of lead with noble metals (gold and silver) to separate them in pure form. Cupellation is based on the fact that lead and other base metals are easily oxidized at high temperatures by atmospheric oxygen, whereas the noble metals are unchanged.

Cupellation is used in assaying to establish the purity of a sample (the content of the noble metals in their alloys). The process takes place in cupels, which are small cups made from a porous refractory material (bone ash, magnesite, and others), at a temperature of 850°-900°C. During cupellation, lead and other base metals are converted into molten oxides, which are absorbed by the cupel, whereas the noble metals remain on its surface as “beads.”

In metallurgy, cupellation is the operation of separating noble metals from argentiferous lead; it is carried out in reverberatory furnaces at a temperature of about 1000°C. Lead and base metals are oxidized by the oxygen blast. The mixture of oxides, in which lead oxide (PbO) predominates, is in liquid form and flows continuously from the surface of the melt into a receptacle. A gold-silver alloy that sometimes contains platinum metals is produced on the hearth of the furnace.

REFERENCES

Loskutov, F. M. Metallurgiia svintsa. Moscow, 1965.
Priborootbiranie i analiz blagorodnykh metallov. Edited by I. F. Barysh-nikov. Moscow, 1968.

V. L. BELOVA and IU. F. VAIMAN

单词	cupellation
释义	cupellation enUK cu·pel·la·tion C0806900 (kyo͞o′pə-lā′shən)n. A refining process for nonoxidizing metals, such as silver and gold, in which a metallic mixture is oxidized at high temperatures and base metals are separated by absorption into the walls of a cupel. cupellation (ˌkjuːpɪˈleɪʃən) n1. (Metallurgy) the process of recovering precious metals from lead by melting the alloy in a cupel and oxidizing the lead by means of an air blast2. (Metallurgy) the manufacture of lead oxide by melting and oxidizing lead Translations coppellazione Cupellation enUK cupellation [‚kyü·pə′lā·shən] (metallurgy) Method using a cupel for assaying precious metals. Process for refining gold and silver by alloying them with lead and then oxidizing the molten lead to separate the base metal from the precious metal. Cupellation oxidation melting of an alloy of lead with noble metals (gold and silver) to separate them in pure form. Cupellation is based on the fact that lead and other base metals are easily oxidized at high temperatures by atmospheric oxygen, whereas the noble metals are unchanged. Cupellation is used in assaying to establish the purity of a sample (the content of the noble metals in their alloys). The process takes place in cupels, which are small cups made from a porous refractory material (bone ash, magnesite, and others), at a temperature of 850°-900°C. During cupellation, lead and other base metals are converted into molten oxides, which are absorbed by the cupel, whereas the noble metals remain on its surface as “beads.” In metallurgy, cupellation is the operation of separating noble metals from argentiferous lead; it is carried out in reverberatory furnaces at a temperature of about 1000°C. Lead and base metals are oxidized by the oxygen blast. The mixture of oxides, in which lead oxide (PbO) predominates, is in liquid form and flows continuously from the surface of the melt into a receptacle. A gold-silver alloy that sometimes contains platinum metals is produced on the hearth of the furnace. REFERENCES Loskutov, F. M. Metallurgiia svintsa. Moscow, 1965. Priborootbiranie i analiz blagorodnykh metallov. Edited by I. F. Barysh-nikov. Moscow, 1968. V. L. BELOVA and IU. F. VAIMAN ThesaurusSeecupel
随便看	saint barthélémy saint barts saint basil saint basil of caesarea saint basil's cathedral saint basil the great saint beda saint bede saint bede the venerable saint bede, the venerable saint benedict saint benedict biscop saint benedict (disambiguation) saint bernadette saint bernadette of lourdes saint bernard saint bernard de clairvaux saint bernard of clairvaux saint bernard parish saint bernard parish, la saint bernard parish, louisiana saint bernard pass saint-bernard's-lily saint bernard state park saint bonaventura

cupellation

cu·pel·la·tion

cupellation

Cupellation

cupellation

Cupellation

REFERENCES