Aluminium dross

Dross is a mass of solid impurities floating on a molten metal. It appears usually on the melting of low-melting-point metals or alloys such as tin, lead, zinc or aluminium, or by oxidation of the metal(s). It can also consist of impurities such as paint leftovers. It can easily be skimmed off the surface before pouring the metal into a mold or casting flask.

With tin and lead the dross can also be removed by adding sodium hydroxide pellets, which dissolve the oxides and form a slag.

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.[1]


Etymology and usage

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.[2] Dregs[2] and the geological term druse are also thought to be etymologically related.[3] Metallurgical dross is referenced as a metaphor for worthless material in the Bible and in other religious texts.[note 1]

See also

  • Aluminium alloy inclusions



  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.",[4] in the Book of Proverbs,[5] and in the Book of Mormon (Alma 32:3 ) "Therefore they were poor; yea, they were esteemed by their brethren as dross..".[6]

External links

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  • dross — ● dross nom masculin (anglais dross, déchet) Populaire. Résidu laissé par l opium une fois qu une pipe a été fumée. ⇒DROSS, subst. masc. Résidu provenant de la combustion de l opium. Il faudrait fumer douze pipes pour récupérer l effet d une… …   Encyclopédie Universelle

  • dross|y — «DRS ee, DROS », adjective, dross|i|er, dross|i|est. having or containing dross; like dross; impure …   Useful english dictionary

  • Dross — (dr[o^]s; 115), n. [AS. dros, fr. dre[ o]san to fall. See {Dreary}.] 1. The scum or refuse matter which is thrown off, or falls from, metals in smelting the ore, or in the process of melting; recrement. [1913 Webster] 2. Rust of metals. [R.]… …   The Collaborative International Dictionary of English

  • dross — [drɔs US dra:s, dro:s] n [U] [: Old English; Origin: dros] 1.) something that is of very low quality ▪ Most of the poems were pretentious dross. 2.) waste or useless substances ▪ gold with impurities or dross …   Dictionary of contemporary English

  • dross — [ dras ] noun uncount something that is of very poor quality: I d rather turn the radio off than listen to this dross …   Usage of the words and phrases in modern English

  • dross — dross·er; dross; …   English syllables

  • Dross — Dross. См. Шлак. (Источник: «Металлы и сплавы. Справочник.» Под редакцией Ю.П. Солнцева; НПО Профессионал , НПО Мир и семья ; Санкт Петербург, 2003 г.) …   Словарь металлургических терминов

  • dross — dirt, dregs, O.E. dros the scum thrown off from metals in smelting, from P.Gmc. *drohs (Cf. M.Du. droes, Du. droesem, M.L.G. dros, O.H.G. truosana, Ger. Drusen dregs, husks ), from PIE dher (1) to make muddy. Meaning refuse, rubbish is mid 15c …   Etymology dictionary

  • dross — ► NOUN 1) rubbish. 2) scum on the surface of molten metal. ORIGIN Old English …   English terms dictionary

  • dross — [drôs, dräs] n. [ME & OE dros, dregs, akin to dærst & ON dregg, DREGS] 1. a scum formed on the surface of molten metal 2. waste matter; worthless stuff; rubbish drossiness n. drossy adj. drossier, drossiest …   English World dictionary

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