What Is Composition Of The Alloy 'Mischmetal'?


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Akshay Kalbag answered
Mischmetal is an alloy that derives its name from the German word 'Mischmetall', which means mixed metals. It is a combination of rare earth elements. All the elements that make up Mischmetal are present in the proportions in which they occur naturally. It is also known as misch metal, cerium mischmetal or rare earth mischmetal. Typically mischmetal is composed of about 50 per cent cerium and 45 per cent lanthanum.

The remaining five per cent is made up mostly of small amounts of neodymium and praseodymium. It is mostly used to make the flint ignition device used in lighters and torches. An alloy of purely rare-earth elements would be unable to give good sparks, as they would be too soft. Hence they are reinforced by blending them with iron oxide and magnesium oxide, which results in a material called ferrocerium, which is much harder than an alloy made up entirely of a combination of rare-earth elements. It is virtually unable to distinguish one rare-earth element from another as such elements practically have identical elements in most chemical processes. That is the reason why mischmetal is used in the preparation of all rare-earth elements. It is used in steel foundries to prepare the FeSiMg alloy, remove oxygen and sulphur by forming stable oxysulphides and tying up trace elements such as lead and antimony which are harmful, and processed into various shapes of ingots, rods, pieces, discs, wires and slabs of metal. There are subtle differences in the solubility of each of the rare-earth elements which have been exploited by the highly-specialised processes developed Carl Auer von Welsbach. These differences can separate each of the elements constituting mischmetal. At each step there is an increase in the composition of each element.

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