Laval University

From the SelectedWorks of Fathi Habashi

July, 2012

Zinc From India. The rP otector of Iron Fathi Habashi

Available at: https://works.bepress.com/fathi_habashi/506/ from India - The protector of iron

By Fathi Habashi*

ZINC has been used for protecting iron against corrosion by immersing iron in molten zinc to form a protective layer. The process is known as

i7#th¥Etfrfamnesdci:#t::ttuhf8jngt::Vein(e]3i:: Fig 1 Schematic nomenon of electric current but misinterpreted representation of its cause. The idea of cathodic protection the Indian method against corrosion was first proposed by for producing zinc Humphry Davy (1778-1829) in London. He initiated the use of zinc for the control of the Fig 2 Chinese corrosion of ships' hulls. Cerituries before zinc method for pro- was prepared in the metahic form, its were ducing zinc

;Seefeuf:p:rdo?¥:8#;a¥:t:igcs¥i,sC:°:::%s:d]: Fig3 Andreas Sigismund described in the Hindu book `Rasamava' which Marggraf (1709- was written around 1200 AD. The fourteenth 1782) described in detail the produc- :::::Fed h=jn:#e ne%as.:ia.tfi:aes,Sa:eutcalhct:¥ tion of zinc from made by indirectly heating calamine with char- calamine coal in a covered crucible fitted with a condens- er. Zinc vapour was evolved and air cooled in the condenser located below the refractory cru- cible (Fig 1,. By 1374, the Hindus had recognised that Z?tch¥taii:,exg:taiti?:de±g|unt:y:ot::ear:

#azsfhca::ogrdeuacttlLoena;sa:fT:rfurvr::.ofttsza:¥g;einr (Fig 2), and, after being brought to redness, are gave the name `contrefey' because it was used 130kt of residue bear testimony to extensive cooled and broken. The metal is found in the to imitate gold. This often consisted of metallic zinc production from the twelfth to sixteenth centre in the fom of a round lump. Zinc pro- zinc, although he did not recognize it as such. duction expanded and the metal began to be ::nJ::i:sri,Ei;nreepfisieonnt:.E:ees::aft::fr:fz:i: exporteda £:rs;:¥tahbe°:i:t6e°n°c'eEo¥rz°£::nscientistswere and . In an extensive research `On the method of `F:ocmhFn°d!:,eyin:I::nsuffea:turemovedtochina European production extracting zinc from its true , calamine', From China, zinc becane known in Europe in 1746 Andreas Marggraf (Fig 3) reduced through Portuguese and Arab traders. It was calamine from sources in Sflesia (Germany) and where it developed as an industry to supply the Albertus Magnus (ca 1248) in the Holy Roman in England and Hungary with carbon in closed needs of manufacture. The Chinese Empire of the German Nation who was the first retorts, and obtained metallic zinc from all of apparently learned about zinc production to describe how calamine might be used to them. He described his method in details there- sometime around 1600AD. An encyclopaedia colour copper `gold'. Biringuccio (ca 1540) in by establishing the basic theory of zinc produc- issued in the latter half of the sixteenth century Italy described how calamine could be mixed tion. I makes no mention of zinc, however, the book with pieces of copper, and sprinkled with a layer `Tien-kong-kai-ou' published early in the seven- of powdered glass, then heated in a closed cru- Suggested readings teenth century related a procedure for zinc cible for 24 hours. Agricola in Saxony in 1546 F Habashi, Readings in Historical Metallurgy, Vol 1 manufacture. Calamine , mixed with pow- reported that a white metal was condensed and `Changing Technology in Extractive Metallurgy', dered charcoal, was placed in clay jars and heat- scraped off the walls of the furnace when M6tallurgie Extractive Quebec, Quebec City, Canada ed to evolve zinc vapour. The crucibles are piled Rammelsberg ore was smelted in the Harz 2006, 800 pages. Distributed by Laval University up in a pyramid with lump coal between them Mountains to obtain lead and silver to which he Bookstore `Zone'. www.zone.ul.ca

* Laval Univer5ity, Quebec City, Canada [email protected]

72 -July/August 2012 -Steel Times International wvvvv.steeltimesint.com