Space metal products

Message: 8
Date: Sun, 14 Mar 2004 16:16:58 -0600
From: "Joe"
Subject: RE: Two Spheres

[Snip]

>> [George Perkins wrote:]
>> Yes, the liquid metal looks very good to me. I like it.

> But I wasn't talking about liquid metals - I was talking about
amorphous
>(non-crystalline) metals, many of which are (and some are VERY)
transparent.
> They are also generally stiffer than their crystalline brethren.
Trouble
> is, making them in containers contaminates your stock and provides
centers
> of crystallization, which ruins the final product; likewise gravity
creates
> density driven currents in the cooling metal which encourages
> crystallization. As a result, it seems like free fall is the best
place to
> make this family of neat materials.

> Were you talking about iron carbonyl [Fe(CO)5], and similar compounds?
I am
> really not current on them - other than the mention they get in
Zubrins
> "Entering Space" (pg 155-156). It does seem a neat concept and, if
the
> information presented is accurate, possibly useful in space-based
refining;
> though he never mentions any advantage of using these compounds in low
or
> zero G. Can they only be formed in free fall? If not, why isn't this
> process already being used?

[Snip]

In a bizarre move to reply to my own point: Metal Carbonyls are
really neat, but they have problems. One is that they apparently cannot
be formed from just any feedstock, or from just any metals. The limited
web searching I've done suggests that only about fourteen (Vanadium,
Chromium, Manganese, Iron, Cobalt, Nickel, Molybdenum, Technetium,
Ruthenium, Rhodium, Tungsten, Rhenium, Osmium, and Iridium) metals
commonly form carbonyl compounds, and that only two (Iron and Nickel)
form from the reletively easy 'direct' reaction. They are also VERY
(more than hydrogen cyanide) toxic, and some of them are gaseous at room
temperature.

Nickel Carbonyl was apparently the first of these to be
synthesized, and was studied in 1890; the formation of nickel carbonyls
was shortly thereafter put forward as an industrial refining process for
nickel, but I've no idea, at the moment, how much it was used.
Apparently some companies today continue to use this process (or at
least hundreds of tons of nickel carbonyl) and do so under very
stringent safety procedures.

I guess I should also observe that many of the metals which do
form carbonyls aren't terribly useful; I mean, how many products can you
name that are made out of Technetium? Iron has obvious uses, and in the
process of making steel alloys you'll want to have certain amounts of
Vanadium, Tungsten, Molybdenium, Nickel, and Chromium on hand. Osmium
and Iridium can be used in certain very specialized alloys, but aren't
very useful on their own... but the rest seem to be just a rogues
gallery of relatively unimportant metals. Copper is conspicuously
absent. The carbonyl sythesis reactions of iron and nickel could be
useful to asteroid miners in another way though - form the carbonyls
through the easy 'direct' reaction, thereby eating away or dissolving
the majority of the mass of a nickel-iron asteroid; whatever is left may
be interesting - and will require a LOT less digging to get to.

Just my $.02 contribution.