I would be interested in more info as well. The older components I'm currently processing have a considerable quantity of Tantalum caps.
From the research I've done so far, tantalum oxide, as recovered from the dissolution of them in nitric has very little value, as it requires a lot of heat & additional processing to get to tantalum metal, which is more saleable, presumably. The solid Tantalum slugs, insoluble in nitric, are easily separated after dissolution.
Mil-spec & aeronautics may have tantalum canisters, as well as tantalum slugs &/or frits. The usual canister is silver, all I've encountered so far have a shrink-wrap plastic label/sleeve. The lead running from the slug is also tantalum, though it usually runs through a nickel sleeve.
One configuration, consisting of 2 single digit LED alpha-numeric displays & a slide rheostat, & necessary electronics, measuring about 6''X4", has 6 of these - the slugs, after dissolution & cleaning weigh .278g each - therefore one unit has 1.668g, or approx. 0.05oz/T. The silver is a plus.
Appreciate any input/feedback.
thanks.
dtectr