Talk:Mischmetal

Someone in the know should really give more info on the separation procedures. I hear they're long and involved, but it would be a good reference for students of chemistry.--Joel 08:06, 30 May 2005 (UTC)

I removed the phrase claiming that "geological processes" do not segregate rare earths; as a geochemist who works with REE's, I know thats not true. In fact, the differention b/w REE's by geological processes is crucial to isotope geochemistry.-- DZ Oct. 15th, 2005
 * Thanks! Always nice to learn something new.  Would you say it's true to a small degree, or that it's entirely untrue?  I understand that zirconium and hafnium are always found mixed together, as well, but I would assume that many processes would give at least an incomplete separation between the different elements.  Feel free to expand the article!--Joel 21:00, 17 October 2005 (UTC)

I removed the following "Mischmetal, cerium, and the more desirable rare earth elements are related in a way that is somewhat analogous to the relationship between natural uranium, depleted uranium, and enriched uranium." as while the author undoubtedly understands the difference between elements and isotopes the average reader may well not and thus, as read, the entry would be 'wrong'. Mike

"Historically..."
The preparation section of the article starts "Historically, mischmetal was prepared from monazite ...". Could somebody with more knowledge replace "historically" with some dates, e.g. "In the nineteenth century.." or similar. There's a lot of history so "historically" is too vague and effectively meaningless. It feels like this text has been copied from another source and not referenced. Thanks. --mgaved (talk) 18:40, 31 August 2010 (UTC)

Dates?
Dates of discovery — Preceding unsigned comment added by Longinus876 (talk • contribs) 12:49, 21 June 2012 (UTC)

Really sad ...
Really sad when someone quotes a reference or external link but doesn't bother to read it. I came across several metallurgy references some back to 1920's of using Misch metal in manufacturing of higher quality iron alloys. (Most younger writers probably don't realize that a steel industry exists outside of Communist China.) The addition of some Rare Earths, Cerium notably, affects Carbon distribution in high Carbon Iron Alloys. (Initially produced Iron reduced with Coke (Carbon) yields high Carbon content which is oxidized away by Air/Oxygen in Bessemer converter et al methods.) When this initial molten Iron is cast, after cooling the excess Carbon precipitates out. The long strings of weak graphite precipitate allow cracks to easily propagate. Misch metal (50% Cerium mixture; Rare Earths are !expensive! to separate)(Magnesium used more recently, cheaper since the 60's note Magnesium boils 900 degrees before Iron melts) causes the Graphite to precipitate into round balls (stops cracks, enhances machinability) instead of continuous strings, hence the name Nodular Cast Iron. (ref Scientific American, Volume 121 (1919): http://books.google.com/books?id=MsUxAQAAMAAJ&lpg=PA569&ots=edx-94g2eg&dq=Misch%20metal%20cast%20iron&pg=PA569#v=onepage&q=Misch%20metal%20cast%20iron&f=false and other Engineering and Metalurgical Journals) Didn't find a ref but some Misch metal (made from Mozanite which is high in Thorium) contained Thorium also. This tidbit is important because use by the US Steel Industry is what paid for Rare Earth mines to stay open. The re-opening of California 'Mountain Pass Mine' is irrelevant because its raison d'etre was highest Europium (rare, expensive) content worldwide; Europium was the red color in TV Tubes and CRT Computer Monitors. The history of Rare Earth mining has always been as a byproduct of mining something else Uranium, Thorium, Molybdenum, et al. (I wonder what the Chinese do with the first two when they mine Rare Earths?) Shjacks45 (talk) 10:33, 23 June 2013 (UTC)

History section sux
It's about the inventor, not the topic. For example the first several sentences say nothing about the topic, not even to suggest what the topic is: "'Carl Auer von Welsbach was not only the discoverer of neodymium and praseodymium, and co-discoverer of lutetium, but was also the inventor of the light-mantle (using thorium), and of the rare earth industry. He built a factory to manufacture his mantles, and had discovered that the necessary thorium was available from monazite sand, which at the time originated from Brazil, but which soon thereafter was also coming from North Carolina and India. But after the 6-10% thorium content had been extracted from the monazite,'...." --68.127.80.89 (talk) 02:47, 22 September 2013 (UTC)Doug Bashford


 * Someone seems to just be a big fan of Von Welsbach, even including his picture. I noticed seeing the picture twice going from the praseodymium page to this one. Although most of the text did seem to 'lead up' to the subject of the page, I agree it "sucked", in being overly off-topic. I made an attempt to curtail the text, leaving only (what I perceived as) neccesary information. I think it's pretty concise now, although I'm not entirely happy with the first sentence leaving so many of his other discoveries in (not 100% relevant to this page). However, as I'm not able to gauge in which degree his discoveries are needed to mention, I'll leave that to the next (hopefully more knowledgeable) editor that comes along. The picture bothers me personally, but it DOES apparently depict the most relevant person to Mischmetal, so it gets a pass from me. OmikronWeapon (talk) 14:07, 26 June 2015 (UTC)

Economically important usage
Before Magnesium began to be used, Misch metal was an important add to make grey cast Iron into white cast Iron. Only 400ppm of Cerium modifies the excess Carbon in the Cast Iron. (Magnesium only 50ppm). As a large scale use of Rare Earth ore, many US mines shut down with the decline of the US steel industry. TaylorLeem (talk) 17:25, 26 March 2022 (UTC)