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Small porous bowl made of bone ash used in assaying to separate precious metals from e.g. lead
Answer for the clue "Small porous bowl made of bone ash used in assaying to separate precious metals from e.g. lead ", 5 letters:
cupel
Alternative clues for the word cupel
Word definitions for cupel in dictionaries
The Collaborative International Dictionary
Word definitions in The Collaborative International Dictionary
Cupel \Cu"pel\ (k[=u]"p[e^]l), n. [LL. cupella cup (cf. L. cupella, small cask, dim. of cupa) : cf. F. coupelle. See Cup , and cf. Coblet .] A shallow porous cup, used in refining precious metals, commonly made of bone ashes (phosphate of lime). [Written ...
Wiktionary
Word definitions in Wiktionary
n. A small circular receptacle used in assaying gold or silver with lead. vb. To refine by means of a cupel.
Wikipedia
Word definitions in Wikipedia
Cupel may refer to: A porous pot used in cupellation Cupel, Białobrzegi County in Masovian Voivodeship (east-central Poland) Cupel, Legionowo County in Masovian Voivodeship (east-central Poland) Cupel, Ostrołęka County in Masovian Voivodeship (east-central ...
Usage examples of cupel.
If the substance to be assayed is an alloy of silver and copper, first cupel 0.
After the muffle has cooled down for the withdrawal of the last batch, and the old cupels have been taken out, the new cupels for the next batch should be put in their place.
The essential property of a cupel is, that it is sufficiently porous to allow the fused oxide to drain into it as fast as it is formed.
Similarly, fused slags damp and filter through a cupel, but the molten metal not damping it withdraws itself into a button, which is retained.
The cupellation of large quantities of alloy or of alloys which contain tin, antimony, iron, or any substance which produces a scoria, or corrodes the cupel, must be preceded by a scorification.
In places, such as Mints, where large numbers of bullion assays are regularly made a special form of cupel is used so that not less than six dozen assays may all be cupelled at the same time in a muffle of ordinary size.
When the cupel shows signs of the presence of these metals in objectionable quantity, it is well to repeat the assay and scorify so as to remove them before cupellation.
This should be melted down in a small crucible, and the resulting button of lead cupelled.
That it does not do so in the ordinary way of working is shown by the fact that a button of silver equal in weight to the silver lost in cupelling may be got by smelting the cupel and cupelling the resulting button of lead.
Cupel the resulting button of lead, and add 10 grams more of lead towards the close of the operation.
Cupel the lead, and the resulting button will be free from all metals, except perhaps gold.
The dish with the dried residue is then scorified and the resulting button of lead is cupelled.
Karsten got by actual experiment on cupelling copper and lead in equal proportions, a loss of 21.
Everywhere, in the gloom, there were vats, cupels, furnaces, alembics, and matrasses of unhuman form, bulking and towering colossally to the pigmy eyes of Maal Dweb.
Through a habit of observation more or less automatic with the veteran space-pilot, he peered through the doorways of the various rooms that he passed, where the cupels and retorts of a foreign chemistry were tended by age-old colossi.