The aegis & intelligencer. [volume] (Bel Air, Md.) 1864-1923, 1901-04-05
ASSAY OFFICE WORK.
THE MELTING AND REFINING OF GOLD
AND SILVER.


Sans Shops and Have Them Treat
ed at Small Expense.
Anybody can take gold and silver to
the assay sffice In lots Of not less than
500 and have 1t melted or refined BY
paying 4 small charge. Even plated
ware may be taken to Uncle Sans shops,
and the gold OF silver will be separated
from the dross and its value, less the nee
essary charges, returned to the owner.
Where there is no especial artistic value
In the old plate 1t is wise, from bust
ness standpoint, to melt it before selling
1t. Dealers in old plate buy it for its bull
lion value only. They being expert, can
tell what this value is, and If they be not
exactly honest might get much the best
Of the bargain. But when it is melted in
the assay office each bar is stamped with
the exact weight and fneness, SO that
child might take it to market and get its
value.
Not old plate alone goes into the melt
ing pots Of Uncle Sam. Every year hun
dreds of sets of silverware that have new
er left the manufacturers hands are
melted up. These are wares that have
been made in excess of the demand and
have gone out Of fashion, SO that the best
way to realize on them Is to remelt them
and reform them. Some manufacturers
do this remelting themselves, but the gov
eminent does it well and cheaply, SO gets
much of 1t to do. Thus, no bit of silver
is ever lost to the world, and battered old
relics may appear tomorrow In elegantly
chased new designs. As old candy Ia
made over and over into new caramels
until finally eaten, SO Is old silver made
over and over indefinitely.
AL the silver or gold brought in by one
owner Is known as q melt. Each melt Is
handled separately up to the moment the
refining process begins. II the owner
take it away before it is refined, he will
take the identical metal he brought. Re-
timing is done in wholesale quantities,
and IL an owner wants refined metal he
must surrender his impure bullion and
receive in refined metal the quantity the
tests have shown to exist in the gross
bars.
The melting furnaces are run from
o'clock to daily. The fuel is gas, aided
by blast. To melt silver it takes 1900
degrees F.; to melt gold, $500 degrees.
This heat will turn the metal into liquid
In Is minutes. One furnace will run of
<O,OOV OuuCeS O1 SOlu III udy OtOOO VI
silver. Molten silver looks like weak tea
heavy with sugar strip, gold Ike old
tokay. Each has an indefinite, ethereal
appearance that may really exist, but
which more probably exists in the mind
of the observer only because he tries TO
appreciate the extreme value of the liquid
As it Is poured like water from furnace
to mold. The ordinary mold is Of the
size Of q building brick. 1t is Of steel,
the inner surface highly polished and
smeared with sweet lard. As the rich
food falls into It the lard springs into
fame and keeps on burning after the
metal has come to rest, making a little
wall Of fire about it. The odor of burn
ing lard Is strong in the furnace room
while melt Is being poured off. Each
mold when full will hold 200 ounces of
silver or 300 of gold. The metal is left
to stand in the molds but a moment, for
the instant it Is hard enough to stand
alone it Is turned out on to metal table.
At first 1t is a deep red, then gradually
cools and assumes its proper color. The
weight and ineness are stamped before
the bricks leave this table.
Perhaps the most interesting process,
however, Is that of refining. The usual
method Is to put gold and silver into one
melting pot in the proportion Of two
parts Of silver to one of gold. This is
poured off into broad. shallow molds that
leave it when cold in the shape Of waffies
a foot square and a quarter Of an inch
thick and permeated with round holes.
These plates are hoisted to the fifth
floor, where they are boiled for six hours
Ia great pots filled with sulphuric acid.
There are ten of these boiling pots, and
hr1ou ho,,
1900 pounds of acid daily. As you enter
this boiling room the fumes that are
driven from the precious porridge sting
your throat and make you gasp and
cough, but the men who work here have
been years at 1t, and they say their health
Is excellent.
When the boiling process Is finished,
1t is found that the acid has eaten up all
of the metal but the gold. The gold lies
as meal in the bottom of the pots, the
silver and gross metals being held in sus-
pension. The liquid is siphoned off and
run to the floor below, where it is put in
to great copper lined watts. Plates of pure
copper are put into it. Here hot steam is
forced into it. Gradually the silver in the
solution is deposited on the bottom and
sides Of the watts in white meal, its
place in the solution being taken by cop
per, until all the silver has been depos-
tied.
The liquid siphoned from the gold is
sulphate Of silver. Now it is siphoned
from the silver as sulphate of copper.
This sulphate Of copper is run now into
watts on the floor below, where it is left
standing for FIVE days in zinc lined watts
into which strips of pure zinc are sus-
pended. The copper in the liquid crys-
tallizes on the strips Of zinc as blue
vitriol.
The first Of these crystals are weak and
dull, and they are made into a second So
luton, after which they form crystals Of
q blue 80 brilliant that it delights the
eye and seems too beautiful to be the
deadly poison that it is. This blue vitriol
Is sold for 31A cents a pound for making
electric batteries. 1t can be reduced back
to the original copper, but the govern
ment has not room to handle it and finds
1t simpler to sell it and buy fresh copper.
There is still per cent Of copper in the
liquid, besides lead and any other gross
metals that might have been In the origi-
nal plate or gold dust. This liquid is sold
copperas, paris green or fertilizer. Thus
every iota of the original mess is account
ed for. II there be not too much dross in
the metal the silver and gold meal left
behind Is very pure. The gold and silver
can be remixed and re-reined over and
ever until practically pure. They are sel-
dom made more than 800 pure.-New