Hey, I never thought I would have to put up a page on this subject
but it seems there is a lot of confusion on this point. At least
it will be short. Probably a one or two beer page.
There is a whole bunch of difference between melting and smelting.
We are gonna try to put this subject to rest. It is simple but I
seem to have a big problem trying to explain the difference. I think
we all understand pretty well what it means to melt something. That
is what happens when you put a glob of hog lard in a frying pan
and stick heat to it. It is what happens when you touch a piece
of solder to a hot soldering iron. It is the changing of a solid
to a liquid by the application of heat. When the heat is removed
the melted material returns to it's solid state. It's chemical content
has not been changed. O.K., maybe if it was a powder when you stuck
the heat to it, when it cools, it will probably be just a lump of
something that is not finely divided. It is still the same stuff
with the same composition. If it was 20% Zinc when in a powder form,
it is still 20% Zinc after it cools to a solid lump. Are ya with
me? Yeah, I think so. That ain't too hard to grasp, even for us
Now, there is a thang called "smelting". That is a metallalurgical
term. It really has nothing to do with "melting" other than the
fact that both thangs have to be done at high temperatures where
the material in question is probably a liquid. Just a coincidence.
Lets try explaining the difference with a "fer instance".
Fer instance, if I had 10 grams of Gold. Hell, we all know
it ain't all gold. So lets say it is 20% copper and 80% Gold.
If it happens to be in a powder form and we melt it down to
a nice lump of metal, it is still 20% Copper and 80% Gold.
Right? Don't want to lose anyone this early.
O.K., so you are a purist and don't like the idea that your
beautiful lump of metal has all that nasty Copper in it. Won't
do no good at all to melt it again. You just end up with the
same stuff. So, being a Basement Chemist, how are you gonna
skin that cat? Well, one way is to smelt it. So how does that
differ from melting? Physically, not much but chemically it
is like being on a different planet. So what is this great
difference that we are going to utilize? We are simply going
to subject the molten metal to a highly "oxidizing" environment.
Hey, you know about redox. You also know that it is very difficult
to "oxidize" Gold but pretty easy to "oxidize" Copper. That
is why Gold stays nice and shiny but Copper turns green pretty
quick. Well, that is what we Are gonna use to clean up our
gold a little. We only have to do two things. First we have
to convert the Copper to some salt that will not form an amalgam
with Gold. Second, we have to give the Copper salt some way
to "escape" from the Gold. Hey, that ain't no big problem
for a Basement Chemist.
O.K., now an easy, cheap, way to this is simply mix the
Gold/Copper with an "oxidizing agent" such as Sodium Nitrate.
That will get the job done. However, the Copper is sort
of "locked up" inside the Gold so the Nitrate can't really
get at it. Hey, we solve that problem by melting the whole
mess. Now the nitrate can contact the Copper and oxidize
it to Cupric Nitrate. Yeah, yeah, I know you all knew
that but I had to say it.
Well, that solves the problem, right? Remember, we still
have to get the Gold and Copper Nitrate separated. Otherwise,
it will just be sort of a mixed mess. Hey, we can do that
too. What we gotta do is provide a second liquid that
will dissolve the Copper Nitrate but not the Gold. And
it has to be a liquid at the temperature of molten Gold.
Water don't last long at that temperature. So what we
are gonna do is use a hi-temp liquid. Molten glass works
great. So you just got to toss in some white, quartz construction
sand, a smashed up disposable beer bottle, or a smashed
piece of yr wife's best crystal (if you got the balls).
Any of that stuff will work.
So now we got the nitrate, we got the silica (beer
bottle). We heat that up with the Gold/Copper until
it all melts. About 1,100 deg C or 1,800 deg F. Now
all we have to do is pour it into some sort of mold
and let it cool, (you can use that cast iron breadstick
pan that yr wife has stashed away somewhere), bust
off the glass containing the Copper and we got a button
of pretty good Gold.
But, wouldn't ya know it. Sumpin went to hell. The
molten goo was so thick it just wouldn't pour out
of the crucible. Maybe you should use a different
brand of beer bottle. Well, before we go to that extreme,
lets see if the wife has some ol 20 Mule Team Borax
lurking around the kitchen/utility room somewhere.
Now if you just toss a teaspoon of that stuff right
in the mix with her smashed crystal, you will find
that when it melts, it will be much thinner and you
can pour it much easier.
Now you just bash off the glass and you will
find that your Gold is much cleaner than when you
started. Now it is probably 95% Gold and 5% Copper.
I can't guarantee the numbers, but something like
So, fellow scientists, that is the difference
between Melting and Smelting. It ain't near
as complicated as getting a Wiffle table adjusted
right. How many beers did this page take?
stuff is Really Great! I think it has sumpin
to do with Gynocoligy or maybe Proctology. I
just larned them words, ain'tcha proud of me?