We often use a broad based glass petri dish to spread out the capsules so they don’t stick. Marilyn
I recommend Scott’s temperature for the muffle furnace, and you can even go a little lower. Once you get into the high 300’s, you will start to see the capsules become slightly stuck together. Higher temperature, even for just an hour, can result in some capsules stuck together beyond reclamation, so be careful to watch the capsules closely. We regularly roast our Ag foil capsules for 2 hours in a muffle furnace at a mere 325C and get very shinny capsules as a result. You won’t need any He flow; the oxidation will simply go away. Don’t be surprised if they come out in a “clump” even if you use lower temperatures. This is easily solved by putting the capsules in a beaker and gently rolling them around; you’ll preserve their shape and won’t have to individually pull the capsules apart.
--Anthony J. Menicucci
Stable Isotope Laboratory Manager
School of Geosciences
University of South Florida
The oxidation on silver capsules can be removed by heating in air at 375oC for one hour prior to use.
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----------------------- Original Message -----------------------
Date: Tue, 4 Dec 2018 18:33:21 +0000
Subject: [ISOGEOCHEM] Oxidized silver capsules
In the wild days before it became a cost center, someone purchased many thousands of silver capsules for our TC/EA. Unfortunately, most have oxidized just in time for us to get our TC/EA up and running. Even some of the capsules that appear unoxidized are giving us blank issues.
Has anyone tried to salvage oxidized silver capsules? I'm thinking of setting up something to stream hydrogen over a load of capsules while gently heating them, but perhaps there's another way? Preferably one that doesn't involve the phrase "just throw them out and buy more"?
All input is much appreciated,
Jordon Munizzi, PhD
Research Facility Manager
Department of Earth and Environmental Sciences
University of Kentucky
Ph: (859) 270-9177
Fax: (859) 323-1938
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