[meteorite-list] Simplified Meteorite Rust treatment

From: meteorites_at_space.com <meteorites_at_meteoritecentral.com>
Date: Thu Apr 22 09:46:21 2004
Message-ID: <20010501160619.9942.cpmta_at_c000.snv.cp.net>

Over the years I have been experimenting with various methods of neutralizing FeCl3 and NiCl3 (Cl2 also) in meteorites.

Now I have found that it can be done with 70% isopropyl rubbing alcohol right off the drug store shelf, and Red Devil lye (sodium hydroxide).

Use as much isopropyl to cover the specimen in a glass or tupperware container, then add a teaspoon of Red Devil lye, or as much as the solution can absorb. If after a few days the first teaspoon dissolves, then add a bit more. This can be done with or without the specimen in the solution.

Let the specimen soak in the container (covered) for a week or more. Don't be alarmed to see rusticles (sort of like those on the Titanic) forming. This is a clear indication that the chemical reaction is taking place, and the Cl is being absorbed by the Na in the solution, and the OH is attaching in its stead to the Fe forming a non corrosive FeOH and or NiOH. (These are the "rusticles" that you see)

If during this time you see that the solution is turning rust brown, pour it and add fresh 70% isoproypl and another dash of Red Devil lye. After a week or two. Remove the specimen from the solution and allow it to dry. After a few days lightly sand it to remove the rusticles, then set it uncoated for a week or more to see if it still bleeds chlorides of iron or nickel. If it does, repeat the process for another week or more.
I have found this process to work well with Mt. Dieu, Brahin, Brenham, Canyon Diablo, Campo del Cielo, and other rusters. With pallasites, the crystals will sometimes rise a bit in their sockets, but once dry the FeOH that holds them will turn into tougher iron oxides. Sanding it down will make the surface level again. And I have found that after the light sanding, a day or so additional soak of pallasites is a good idea. Then dry and polish afterwards. For the really stubborn specimens, I will be working on a simple electrolosis addition to the above mentionned solution. This involves using a battery and a good resistor to create a small current that will drive the Cl ions out of and away from the meteorite. Will post as soon as I test the idea and get some solid results. Steve Schoner, American Meteorite Survey; http://www.geocities.com/american_meteorite_survey

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Received on Tue 01 May 2001 12:06:19 PM PDT