Dross

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For the Austrian municipality, see Droß.
Aluminium dross

Dross is a mass of solid impurities floating on a molten metal or dispersed in the metal, such as in wrought iron. It forms on the surface of low-melting-point metals such as tin, lead, zinc or aluminium or alloys by oxidation of the metal(s).

With wrought iron, hammering and later rolling removed some dross.[1] With tin and lead the dross can be removed by adding sodium hydroxide pellets, which dissolve the oxides and form a slag. Dross can also be skimmed off.

Dross, as a solid, is distinguished from slag, which is a liquid. Dross product is not entirely waste material; aluminium dross, for example, can be recycled and is used in secondary steelmaking for slag deoxidation.[2]

Etymology and usage[edit]

The term dross derives from the Old English word dros, meaning the scum produced when smelting metals. By the 15th century it had come to refer to rubbish in general.[3] Dregs,[3] and the geological term druse are also thought to be etymologically related.[4] Metallurgical dross is referenced as a metaphor for worthless material in the Bible and in other religious texts.[note 1] [note 2]

See also[edit]

Notes[edit]

  1. ^ In the Book of Ezekiel 22 v 18 : "Son of man, the house of Israel is to me become dross: all they are brass, and tin, and iron, and lead, in the midst of the furnace; they are even the dross of silver.",[5] in the Book of Proverbs,[6] and in the Book of Mormon (Alma 32:3 ) "Therefore they were poor; yea, they were esteemed by their brethren as dross..".[7]
  2. ^ In the Buddhist text, the Dhammapada: 239. One by one, little by little, moment by moment, a wise man should remove his own impurities, as a smith removes his dross from silver.,[8]

References[edit]

  1. ^ Landes, David S. (1969). The Unbound Prometheus: Technological Change and Industrial Development in Western Europe from 1750 to the Present. Cambridge, New York: Press Syndicate of the University of Cambridge. p. 91. ISBN 0-521-09418-6. 
  2. ^ Kogel, Jessica Elzea; Society for Mining, Metallurgy, and Exploration (2006), Industrial minerals & rocks: commodities, markets, and uses (7th ed.), SME, p. 1406, ISBN 978-0-87335-233-8. 
  3. ^ a b "Dross". www.etymologyonline.com. 
  4. ^ Chambers's Etymological Dictionary of the English Language. W & R Chambers. 1875. p. 142. 
  5. ^ "Ezekiel 22:18". The Bible (King James version). www.biblegateway.com. 
  6. ^ "Proverbs 25:4". The Bible (King James version). www.biblegateway.com. 
  7. ^ "Alma 32:3". The Book of Mormon. http://lds.org/scriptures/. 
  8. ^ Buddharakkhita, Acarya. "The Dhammapada, section XVIII". Access To Insight. Retrieved 11 September 2013. 

External links[edit]