Re: Copper Casting In America (Trevelyan)

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

Date: Sun, 04 Jul 2004 10:55:17 GMT

Eric Stevens wrote:
>
> On Sat, 03 Jul 2004 07:27:39 GMT, Seppo Renfors <Renfors@not.com.au>
> wrote:
>
> >
> >
> >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.
>
> http://www.cop.ufl.edu/safezone/prokai/pha5100/eumix.htm illustrates
> the basic mechanism. The same kind of thing happens with copper and
> silver. The presence of silver will lower the melting point of the
> copper and a solid solution will be formed. In the case of copper and
> silver

Yeah well..... that isn't really what happened despite there being
several substances in that same solution - as they would all have
ended up in one glorious mix.

> http://www.bipm.fr/metrologia/ViewArticle.jsp?VOLUME=25&PAGE=41-47
> gives the lowest melting temperature as 779.583 plus-minus 0.060 which
> is lower than the melting point of either copper or silver.
>
> Many metals will form similar eutectic mixtures with copper,
> particularly aluminium and zinc. Some tin-lead solders will form
> eutectic mixtures with high alloy steels at quite low temperatures,
> which is why at an early stage they stopped soldering identifying
> labels onto aircraft undercarriage legs. :-)

Never had anything fly off an aircraft that wasn't intentionally
thrown out of it..... or a mob of disgruntled passengers who decide to
get off in mid air at some 4000 ft as it is the fastest way to the
pub....

> >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!
>
> I suggest you read the opening paragraphs of
> http://www.minsocam.org/MSA/collectors_corner/vft/mi2c.htm
> Please don't take this as a contradiction. I intend it as an
> elucidation. :-)

Actually that is a page I had found... but lost again, as I wanted to
use an image from there to demonstrate the NEED to melt even pure
copper:

http://www.minsocam.org/MSA/collectors_corner/vft/img/whitepinecu.jpg

A good site!!

> >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??
> >
> >
> >[..]
>
> Eric Stevens 

-- 
SIR - Philosopher unauthorised 
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