Non-ferrous metal
Inmetallurgy,non-ferrous metalsare metals oralloysthat do not containiron(allotropes of iron,ferrite,and so on) in appreciable amounts.
Generally more costly thanferrousmetals, non-ferrous metals are used because of desirable properties such as low weight (e.g.aluminium), higherconductivity(e.g.copper),[1]non-magneticproperties orresistance to corrosion(e.g.zinc).[2]Some non-ferrous materials are also used in the iron andsteelindustries. For example,bauxiteis used asfluxforblast furnaces,while others such aswolframite,pyrolusite,andchromiteare used in making ferrous alloys.[3]
Important non-ferrous metals include aluminium, copper,lead,tin,titanium,and zinc, and alloys such asbrass.Precious metalssuch asgold,silver,andplatinumand exotic or rare metals such asmercury,tungsten,beryllium,bismuth,cerium,cadmium,niobium,indium,gallium,germanium,lithium,selenium,tantalum,tellurium,vanadium,andzirconiumare also non-ferrous.[4]They are usually obtained through minerals such assulfides,carbonates,andsilicates.[5]Non-ferrous metals are usually refined throughelectrolysis.[6]
Recycling and pollution control[edit]
Due to their extensive use, non-ferrousscrap metalsare usuallyrecycled.The secondary materials in scrap are vital to the metallurgy industry, as the production of new metals often needs them.[7]Some recycling facilities re-smelt and recast non-ferrous materials; thedrossis collected and stored onsite while the metal fumes are filtered and collected.[8]Non-ferrous scrap metals are sourced from industrial scrap materials, particle emissions and obsolete technology (for example,copper cables) scrap.[9]
Ancient history[edit]
Non-ferrous metals were the first metals used by humans for metallurgy. Gold, silver and copper existed in their nativecrystallineyet metallic form. These metals, though rare, could be found in quantities sufficient to attract the attention of humans. Less susceptible to oxygen than most other metals, they can be found even in weathered outcroppings. Copper was the first metal to be forged; it was soft enough to be fashioned into various objects bycold forgingand could be melted in acrucible.Gold, silver and copper replaced some of the functions of other resources, such as wood and stone, owing to their ability to be shaped into various forms for different uses.[10]Due to their rarity, these gold, silver and copper artifacts were treated as luxury items and handled with great care.[11]The use of copper also heralded the transition from theStone Ageto theCopper Age.TheBronze Age,which succeeded the Copper Age, was again heralded by the invention ofbronze,an alloy of copper with the non-ferrous metaltin.[10]
Mechanical and structural use[edit]
Non-ferrous metals are used in residential, commercial and industrial applications. Material selection for a mechanical or structural application requires some important considerations, including how easily the material can be shaped into a finished part and how its properties can be either intentionally or inadvertently altered in the process. Depending on the end use, metals can be simply cast into the finished part, or cast into an intermediate form, such as aningot,then worked, or wrought, by rolling,forging,extruding, or other deformation process. Although the same operations are used with ferrous as well as nonferrous metals and alloys, the reaction of nonferrous metals to these forming processes is often more severe. Consequently, properties may differ considerably between the cast and wrought forms of the same metal or alloy.[12]
References[edit]
- ^Fahlman, Bradley D. (18 March 2011).Materials chemistry(2nd ed.). Dordrecht [u.a.]:Springer.ISBN978-94-007-0692-7.
- ^"Non-Ferrous Metals".Engineers Handbook.Archived fromthe originalon 4 June 2016.Retrieved25 October2011.
- ^Gupta, R. C. (2010).Theory and laboratory experiments in ferrous metallurgy.New Delhi:PHI Learning Private Ltd. p. 6.ISBN978-81-203-3924-8.
- ^"Commonly Recycled Metals and Their Sources"(PDF).lOccupational Safety and Health Administration.Retrieved27 October2011.
- ^Young, Courtney A., ed. (2008).Hydrometallurgy 2008: proceedings of the sixth international symposium(1st ed.). Littleton, Colo.: Society for Mining, Metallurgy, and Exploration. p. 416.ISBN978-0-87335-266-6.
- ^"Chapter 82 – Metal Processing and Metal Working Industry".Encyclopaedia of Occupational Health and Safety, 4th Edition.Retrieved26 October2011.
- ^"Non-Ferrous Metals".Bureau of International Recycling. Archived fromthe originalon 21 October 2016.Retrieved26 October2011.
- ^"Department of the Environment Industry Profile: Waste recycling, treatment and disposal sites"(PDF).Environment Agency. Archived fromthe original(PDF)on 25 April 2012.Retrieved27 October2011.
- ^Robert Noyes (1993).Pollution Prevention Technology Handbook.Noyes Publications.ISBN978-0815513117.
- ^abMcNeil, Ian, ed. (1990).Encyclopedia of the History of Technology.London: Routledge. pp. 47–66.ISBN978-0-203-19211-5.
- ^Forbes, R. J. (1971).Studies in Ancient Technology, Volume 3; Volume 1965.BRILL. p. 16.ISBN978-90-04-02652-0.
- ^"Non-ferrous Metal Applications".All Metals & Forge Group. 16 April 2013. Archived fromthe originalon 24 September 2015.Retrieved1 October2013.
