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July 13

On the discovery of tantalum

What procedure did Anders Gustaf Ekeberg use to isolate metallic tantalum? Double sharp (talk) 09:11, 13 July 2024 (UTC)[reply]

If you can read Swedish, I think this is the original publication in which Ekeberg announced his discovery of tantalum. If you can't, maybe someone who knows Swedish and has some familiarity with the terminology of analytical chemistry will be kind enough to summarize the procedure, which I think is described in the later half of the article; on p.78 I see Detta nya metallämnet ("this new metallic substance"). --Lambiam 11:26, 13 July 2024 (UTC)[reply]

Unfortunately, the Scandinavian languages are something I never looked deeply into. Though it's starting to seem clear that I'm going to need to look into Swedish to study this period of chemical history. :) Double sharp (talk) 12:19, 13 July 2024 (UTC)[reply]

This ref:

Ekeberg, Anders (1802). "Of the Properties of the Earth Yttria, compared with those of Glucine; of Fossils, in which the first of these Earths in contained; and of the Discovery of a metallic Nature (Tantalium)". Journal of Natural Philosophy, Chemistry, and the Arts. 3: 251–255.

might be an English translation (or at least contain discussion of it). DMacks (talk) 22:42, 13 July 2024 (UTC)[reply]

It is a strongly abridged extract of the second half of Ekeberg's article, referring to the newly discovered metal with the incorrrect name tantalium. It does not give the isolation procedure of the elemental metal but only some of its physical properties as well as chemical properties distinguishing it from tin, tungsten and titanium. --Lambiam 09:37, 14 July 2024 (UTC)[reply]

Boo:( DMacks (talk) 18:48, 14 July 2024 (UTC)[reply]

A German translation of the original paper is here. AstroLynx (talk) 19:29, 14 July 2024 (UTC)[reply]

{{ec}} If anyone wants to have a go at manual- or machine-translation from Swedish, I uploaded what en:tantalum and sv:tantal appear to identify as the original article as File:Ekeberg-1802.pdf. My naive first pass with Acrobat was able to do some extraction, but had trouble with some of the diacritical marks and correctly representing them in my system's font, and also gave too many disjointed text fields to make it bulk-selectable. DMacks (talk) 19:32, 14 July 2024 (UTC)[reply]

Thanks. The German translation AstroLynx points to can be copy-pasted from the generated PDF, so here's a somewhat cleaned-up reading of the relevant bit:

Dieser neue Metallstoff zeichnet sich durch seine Unauflöslichkeit in alle Säuren, wie man ihn auch mit denselben behandelt, aus. Das einzige Auflösungsmittel, das ich auf denselben wirksam gefunden habe, ist das ätzende fixe Laugensalz, so daß, wenn man das Erz mit demselben brennt, und das Gemenge mit Wasser auszieht, ein großer Theil in der laugensalzigen Lauge aufgelöst wird. Aus derselben kann er durch eine Säure gefällt werden, aber der Niederschlag wird nicht wieder aufgelöst, wie viele Säure man auch zugießen mag. Abgeseihet und getrocknet erscheint er als ein Pulver von ausgezeichneter Weiße, welche Farbe er auch beym Glühen behält. Wenn der Theil des gebrannten Klumpens, welcher von der laugensalzigen Lauge nicht aufgenommen ist, mit Säure ausgezogen wird, bleibt ein weißes Pulver von gleicher Beschaffensheit nach. Seine eigenthümliche Schwere, nach dem Glühen, war 6,500. Vor dem Blaserohre wird er leicht vom Borax und Phosphorsalze aufgelöst, gibt den Flüssen aber keine Farbe. Auf einem Heerde von Kohlengestäbe in einem Ziegel, ohne Zusaß der Hitze, welche zu einer Braunsteinprobe erfordert wird, ausgefeßt, untergeht er eine Art von Verfrischung, bey welcher er zu einem grünlich harten Klumpen zusammensiedet, welcher auf der Oberfläche einen metallischen Glanz hat, aber im Bruche nur matt glänzt und schwarze grün aussieht. Auf diesen haben Säuren keine weitere Wirkung, als daß fie ihn wieder zu der weißen Halbsäure verwandeln. Das Verhalten bey der Verfrischung und die eigenthümliche Schwere, gaben mir Anleitung, diesen besondern Körper unter die Metalle zu rechnen.

It sounds like the English abridgement omitted to notice the word Erz there. That makes the procedure sensible: it seems that Ekeberg converted the ore via alkaline digestion to Ta₂O₅ (certainly a mixture with Nb₂O₅, though he wouldn't know that), then attempted to reduce it with carbon. This actually should have a quite poor yield under his likely experimental conditions, but clearly, it was enough for him to draw the correct conclusion. I'm extremely impressed. (V, Nb, and Ta are quite a pain to reduce from the oxides to the elemental metals, especially if you want a reasonably pure product.) Double sharp (talk) 10:05, 15 July 2024 (UTC)[reply]

Was the grünliche harte Klumpen (impure) elemental tantalum? It is a pity Ekeberg did not give its specific mass, unlike for the ore, or other physical properties. --Lambiam 18:04, 15 July 2024 (UTC)[reply]