Aluminothermic reactions are exothermic chemical reactions using aluminum as the reducing agent at high temperature. The process is industrially useful for production of alloys of iron.[1] The most prominent example is the thermite reaction between iron oxides and aluminum to produce iron itself:
An aluminothermic reaction using iron(III) oxide. The sparks flying outwards are globules of molten iron trailing smoke in their wake.
Fe2O3 + 2 Al → 2 Fe + Al2O3
This specific reaction is however not relevant to the most important application of aluminothermic reactions, the production of ferroalloys. For the production of iron, a cheaper reducing agent, coke, is used instead via the carbothermic reaction.
Aluminothermy started from the experiments of Russian scientist Nikolay Beketov at the University of Kharkiv in Ukraine, who proved that aluminum restored metals from their oxides under high temperatures. The reaction was first used for the carbon-free reduction of metal oxides. The reaction is highly exothermic, but it has a high activation energy since strong interatomic bonds in the solids must be broken first. The oxide was heated with aluminum in a crucible in a furnace. The runaway reaction made it possible to produce only small quantities of material. Hans Goldschmidt improved the aluminothermic process between 1893 and 1898, by igniting the mixture of fine metal oxide and aluminum powder by a starter reaction without heating the mixture externally. The process was patented in 1898 and used extensively in the later years for rail track welding.
Applications
The aluminothermic reaction is used for the production of several ferroalloys, for example ferroniobium from niobium pentoxide and ferrovanadium from iron, vanadium(V) oxide, and aluminum.[1][2] The process begins with the reduction of the oxide by the aluminum:
3 V2O5 + 10 Al → 5 Al2O3 + 6 V
Other metals can be produced from their oxides in the same way.[3][4][5]
Aluminothermic reactions have been used for welding rail tracks on-site, useful for complex installations or local repairs that cannot be done using continuously welded rail. Another common use is the welding of copper cables (wire) for use in direct burial (grounding/earthing) applications. It is still the only type of electrical connection recognized by the IEEE (IEEE, Std 80-2001) as continuous un-spliced cable.
^Claude Dufresne and Ghislain Goyette. (PDF). Archived from the original (PDF) on 2008-12-17. Retrieved 2008-09-02.
^Davis, Joseph R. (1993). Aluminum and Aluminum Alloys. ASM International. ISBN978-0-87170-496-2.
^Gupta, Chiranjib Kumar (2006). Chemical Metallurgy: Principles and Practice. Wiley-VCH. ISBN978-3-527-60525-5.
^Wang, L. L.; Munir Z. A.; Maximov,Y. M. (1993). "Thermite reactions: their utilization in the synthesis and processing of materials". Journal of Materials Science. 28 (14): 3693–3708. Bibcode:1993JMatS..28.3693W. doi:10.1007/BF00353167. S2CID 96981164.
January 07, 2023
aluminothermic, reaction, exothermic, chemical, reactions, using, aluminum, reducing, agent, high, temperature, process, industrially, useful, production, alloys, iron, most, prominent, example, thermite, reaction, between, iron, oxides, aluminum, produce, iro. Aluminothermic reactions are exothermic chemical reactions using aluminum as the reducing agent at high temperature The process is industrially useful for production of alloys of iron 1 The most prominent example is the thermite reaction between iron oxides and aluminum to produce iron itself An aluminothermic reaction using iron III oxide The sparks flying outwards are globules of molten iron trailing smoke in their wake Fe2O3 2 Al 2 Fe Al2O3This specific reaction is however not relevant to the most important application of aluminothermic reactions the production of ferroalloys For the production of iron a cheaper reducing agent coke is used instead via the carbothermic reaction Contents 1 History 2 Applications 3 See also 4 ReferencesHistory EditAluminothermy started from the experiments of Russian scientist Nikolay Beketov at the University of Kharkiv in Ukraine who proved that aluminum restored metals from their oxides under high temperatures The reaction was first used for the carbon free reduction of metal oxides The reaction is highly exothermic but it has a high activation energy since strong interatomic bonds in the solids must be broken first The oxide was heated with aluminum in a crucible in a furnace The runaway reaction made it possible to produce only small quantities of material Hans Goldschmidt improved the aluminothermic process between 1893 and 1898 by igniting the mixture of fine metal oxide and aluminum powder by a starter reaction without heating the mixture externally The process was patented in 1898 and used extensively in the later years for rail track welding Applications EditThe aluminothermic reaction is used for the production of several ferroalloys for example ferroniobium from niobium pentoxide and ferrovanadium from iron vanadium V oxide and aluminum 1 2 The process begins with the reduction of the oxide by the aluminum 3 V2O5 10 Al 5 Al2O3 6 VOther metals can be produced from their oxides in the same way 3 4 5 Aluminothermic reactions have been used for welding rail tracks on site useful for complex installations or local repairs that cannot be done using continuously welded rail Another common use is the welding of copper cables wire for use in direct burial grounding earthing applications It is still the only type of electrical connection recognized by the IEEE IEEE Std 80 2001 as continuous un spliced cable Rail track welding by thermiteSee also EditThermite Calciothermic reaction Silicothermic reactionReferences Edit a b Rudolf Fichte Ferroalloys Ullmann s Encyclopedia of Industrial Chemistry Weinheim Wiley VCH doi 10 1002 14356007 a10 305 Claude Dufresne and Ghislain Goyette The Production of Ferroniobium at the Niobec Mine MINE 1981 2001 PDF Archived from the original PDF on 2008 12 17 Retrieved 2008 09 02 Davis Joseph R 1993 Aluminum and Aluminum Alloys ASM International ISBN 978 0 87170 496 2 Gupta Chiranjib Kumar 2006 Chemical Metallurgy Principles and Practice Wiley VCH ISBN 978 3 527 60525 5 Wang L L Munir Z A Maximov Y M 1993 Thermite reactions their utilization in the synthesis and processing of materials Journal of Materials Science 28 14 3693 3708 Bibcode 1993JMatS 28 3693W doi 10 1007 BF00353167 S2CID 96981164 Retrieved from https en wikipedia org w index php title Aluminothermic reaction amp oldid 1060460055, wikipedia, wiki, book, books, library,
