dross


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.

dross

the scum formed, usually by oxidation, on the surfaces of molten metals

Dross

 

an intermediate product obtained from the liquation separation of heavy nonferrous metals with low melting points: lead, bismuth, and tin. As the metals are cooled during the refining process, impurities of low solubility, such as copper and iron, crystallize. Denser and possessed of a higher melting point than the metal being refined, the impurities (in the elemental state or in compounds) float to the surface of the bath as solids to form dross. Additives of sulfur or carbon are sometimes introduced into the metal being refined in order to remove a higher percentage of impurities. The deeper the cooled metal, the more complete the crystallization and purification; however, there is also an increase in dross yield and in the amount of refined metal found in the dross.

Dross is removed from the surface of the liquid bath with a skimmer. The liquid metal entrained mechanically with the dross drains into the bath. Dross is highly complex with respect to its chemical and phase composition; the refined metal constitutes its base. The dross obtained in the refining of lead is reprocessed by smelting in a reverberatory or electric furnace with the addition of a sulfidizing agent and fluxes. The smelted lead is returned to the primary production cycle, and the matte and speiss produced are sent to copper mills. The dross obtained in the refining of bismuth and tin is recycled.

REFERENCE

Loskutov, F. M. Metallurgiia svintsa. [Moscow] 1965.

M. P. SMIRNOV

dross

[drȯs]
(metallurgy)
An impurity, usually an oxide, formed on the surface of a molten metal.
References in periodicals archive ?
Once demonstrated, the Agreement anticipates that the Client will engage PyroGenesis to build, install, and operate a DROSRITE plant, with the potential for additional Systems, to process their hot dross on-site, recover and return the metallic aluminum to the Client, and manage the resulting non-hazardous residue.
"We had the contract to process dross on-site and our contract was up for renewal on August 1.
Although aluminium dross is a type of waste, several useful usages have been discovered, such as filler in composite, being used in refractories industry, and also being used as adsorbent.
"As a result, it can be said that the usage of the dross in concrete, decreases its detrimental environmental effect.
Dross shared his belief and determination in expand Asia market: “I am very happy and excited to be joining the fast paced and dynamic Exotic Voyages team.
As a result of decreasing waste via the dross filtering process, all Dross Boss customers have reported ROI in less than a year, according to Q.C.
As per the contract, TIC is to invest in a new system to recover aluminium metal from dross, which is a by-product of aluminium smelting and re-melting.
Dross is a by-product of aluminium smelting and re-melting, which has traditionally been recycled using salts and flux to recover available metal.
Qatalum has sent its dross to Bahrain where it is treated in the old-fashioned way.
A Bahrain company has won a $25 million contract to process dross from an aluminium smelter in New Zealand that could transform the way that waste from smelters across the world is recycled.
People will turn off in droves at the current dross.