Re: Copper Casting In America (Trevelyan)

From: Seppo Renfors (Renfors_at_not.com.au)
Date: 07/03/04 

Date: Sat, 03 Jul 2004 07:27:39 GMT

Gary Coffman wrote:
>
> On Fri, 02 Jul 2004 07:53:30 GMT, Seppo Renfors <Renfors@not.com.au> wrote:
> >Gary Coffman wrote:
> >>
> >> On Thu, 01 Jul 2004 12:10:10 GMT, Seppo Renfors <Renfors@not.com.au> wrote:
> >> >Gary Coffman wrote:
> >> >> On Tue, 29 Jun 2004 07:05:25 GMT, Seppo Renfors <Renfors@not.com.au> wrote:
> >> >> >This has a good story about the Great lakes Copper deposits.
> >> >> >http://www.geo.msu.edu/geo333/copper.html
> >> >>
> >> >> As that article notes, 14 billion pounds of copper have been removed
> >> >> from the area since the ancients were working copper there. Let the
> >> >> enormity of that number sink in. There was an *awful lot* of copper
> >> >> there in ancient times, much of it easily accessible from the surface.
> >> >
> >> >My main interest was to show the formation of the copper deposits -
> >> >the volcanic activity that melted it (and other minerals with it).
> >> >Silver is/was found in fair quantities alongside the copper. What
> >> >isn't known - because nobody cares to find out, is the composition of
> >> >the metal used in the artefacts. It is ASSUMED to be pure copper.
> >>
> >> The presence of silver inclusions *proves* the native copper was not
> >> melted after being deposited.
> >
> >...but only for that piece - not for any other piece. Further more
> >IIRC there is a method of laminating copper and silver *** and
> >carving through one into the other. It is a Japanese technique IIRC.
> >It requires being heated under pressure, to the point the silver just
> >starts "sweating" and it brazes the sheets together. So silver in
> >copper can also be deliberate - as decoration.
>
> It is called silver brazing (or more commonly, but incorrectly, called
> silver soldering).

I already said it was brazing. I couldn't think of the specific
decoration name before, but it is used in making "mokume gane" as
found, and originating on samurai sword handles from about 1600 ->
1800.

> It is a common technique used to join pieces of
> copper. Pressure is not required. A temperature in excess of 800F
> is required for brazing to occur (by ASTM definition).

Are you suggesting silver "sweats" (forms liquid beads) way below its
melting point?

> >> Native copper is deposited by chemical
> >> means, not volcanic melting and extrusion.
> >
> >I already posted this earlier. It disagrees with you:
> >
> >http://www.geo.msu.edu/geo333/copper.html
> >
> >"chemical" doesn't get a single mention.
>
> Actually, it doesn't disagree with me. It says the copper
> was carried in an aqueus solution from great depths
> and deposited in the vents, fissures, and voids of the
> iron bearing rocks above. The pertinent chemical
> reaction involved is
>
> CuSO4 + Fe(Metal) => FeSO4 + Cu (Metal)
>
> If you were knowledgeable of the chemistry of copper, this
> would have been obvious to you. If you had read any of the
> many geochemical references in the links already provided
> in this thread, it would have been spelled out for you in
> excruciating detail.

If you had not been so intent on being snaky you would know that
"aqueous" (correct spelling) also means "water like", "watery" as well
as "of or containing water" - therefor it is NOT a clear explanatory
term in itself. Further to that, you would NOT have written that
formula up there - but if you want to argue that particular formula
(A) point out how two solids, suddenly for no given reason, decides to
react and change (B) how they get together in the first place when
they are NOT ambulatory in any way. Oh and where are these pure iron
deposits, hmmm? It sure as hell would have saved on building blast
furnaces if that existed...

You could have instead pointed to this section in that same article:
"Into the lava flows of Keweenaw, Houghton, and Ontonagon counties
percolating hot waters rising from great depths brought copper and
silver in solution. As it cooled, the waters filled the fissures and
the gas cavities (amygdules) of the lavas (trap rocks) with pure
copper and silver..."

Now here we see something totally different from your "formula". There
IS a mention of a "solution" - most likely the copper portion was
CuSO4.5H2O. There is not a single mention of iron. It also refers to a
heat source - not two ambulatory minerals meeting in the dark for a
bit of kissy kissy, saliva swapping or any other hanky-panky!

So what have we here - we have the result of hot lava, the water
"evaporates" leaving what would be known as, Blue copper, Blue stone
or Blue vitriol (among other things) or CuSO4. Indeed it does exist,
but it isn't your pure Cu, is it.

BUT if I again go back to your "formula" and introduce some "Fe" into
the equation, it has to be as "FeSO4.H2O" solution - 100% water
soluble (used in animal feeds as a supplement). Perhaps more
interesting is the FeSO4.7H2O (copperas), also water soluble, but is
blue in colour similar to copper sulphate and in its solid form it
melts at 64 deg. C! Only problem is that this requires no hanky-panky
at all.... the Fe is pregnant with SO4 already!

So lets add the bit of "mood" to the situation and heat it up with the
cooling lava. The result would indeed be ferrous and cupric oxides,
respectively, giving off water and sulphur trioxide, which combine to
produce a dilute solution of sulphuric acid.

So IF there is either some "copperas" or Ferrous Sulphate Monohydrate
in the CuSO4.5H2O - then one can expect IRON to be present with the
copper - well.... yes but not in the same place by the look of it. But
then if we take both the copper and Iron out of the soup we end up
with H2SO4.... or masses of sulphuric acid (oil of vitriol)! Therefor
Lake Superior is a lake of acid. Then the Moral of the Story is:
don't eat the fish as they will eat your insides out!

Now, I have to admit I have have happily forgotten 99% of what I ever
learned about chemistry (except that needed to make moonshine), but
then again, why on earth am I required to know any of it.....?? To
prevent you getting all snooty by suggesting things??

[..] 

-- 
SIR - Philosopher unauthorised 
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