IMPROVEMENTS IN MUMATA ANTEN BRAN CARPER ORES
Year: 1871

page_text: LETTERS PATENT to Frederic Claudet, of Nos. 6 and 7, Coleman Street,
in the City of London, for the Invention of "IMPROVEMENTS IN
MUMATA
ANTEN
BRAN CARPER ORES"
PROVISIONAL SPECIFICATION left by the said Frederic Claudet at the
Office of the Commissioners of Patents, with his Petition, on the
26th April 1871.
I, FREDERIC CLAUDET, of Nos. 6 and 7, Coleman Street, in the City
of London, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE SEPARATION OF SILVER AND OTHER METALS FROM COPPER
ORES," to be as follows:-
In the humid treatment of burnt Spanish and Portuguese cupreous
pyrites and other similar ores the copper, as is well known, is precipitated
from the liquors by means of metallic iron. The iron used is either
scrap iron or metallic iron in a finely divided state (sponge iron) made
expressly for the purpose. The small quantity of silver present in the
copper liquors is by the processes now employed precipitated along with

page_text: the copper, but the quantity is too small to admit of profitable separa-
tion, except in special cases, as when copper precipitate is employed for
the manufacture of sulphate of copper.
My Invention consists in separating the silver and gold previous to
the precipitation of the bulk of the copper and concentrating the
precious metals in a comparitively small quantity of copper precipitate,
which can then be advantageously dealt with. In order to reduce the
dissolved chloride of silver to the metallic state, the protochloride of
copper in solution must first be transformed into dichloride of copper,
and when this is accomplished I find that a very slight addition of
finely divided iron immediately throws down the silver. To effect the
transformation of the protochloride of copper into dichloride, it is only
necessary to add sufficient iron to combine with one half the chlorine
of the protochloride of copper present, when dichloride of copper and
protochloride of iron are formed according to the formula 2 Cu Cl +
Fe Cu Cl + Fe Cl. When the copper occurs in the form of
protochloride this condition is best obtained by first ascertaining the
quantity of copper in solution, and then adding by weight the calculated
equivalent of finely divided iron, a slight excess of which will then
precipitate the silver along with a little copper. When on the contrary
the liquors already contain a notable quantity of dichloride of copper
the amount of finely divided iron to be added is best determined by
shaking a measured volume of the liquors in a bottle with an excess
of finely divided iron, so as to precipitate all the copper, and then
ascertaining after filtration the amount of iron in solution by the
permanganate test, one half the iron thus found will be the right
proportion to ensure the above reaction.
I now proceed as follows:- -I first prepare finely divided iron by
heating in a retort or close furnace; as is well known, a suitable mixture
of finely ground oxide of iron or purple ore and charcoal or coal, until
the oxide of iron is reduced to the metallic state. Precipitated oxide
of iron or rouge may be used for the same purpose with advantage.
This reduction should be made at a low red heat, as too high a tem-
perature tends to the aggregation of the metallic particles. After the
reduced iron has been brought to a fine state of division by further a
grinding, it is tested in order to ascertain the exact per-centage of
pure iron it contains. The copper liquors are now made to flow into
a round vat or tub of known capacity and supplied with revolving

page_text: arms to keep the liquors in motion, the quantity of copper in solution
is next rapidly determined by the cyanide of potassium test, or otherwise,
and the amount of iron necessary to convert the protochloride of copper
into dichloride is ascertained. A weighed quantity of finely divided
iron is now taken containing from 1 to 5 per cent. more puro iron than
the quantity theoretically necessary, and is gradually introduced into
the copper solution by causing it to pass through a wire gauze sieve
so as to separate the particles as they fall into the liquid. The copper
solution is kept constantly in motion, a considerable rise of temperature
takes place, and the copper is rapidly transformed into dichloride, which
for the most part is held in solution by the alkaline and metallic
chlorides present. The reaction is complete when the solution from
green becomes nearly colorless, then agitation is continued for a few
minutes, and then the solution is run off into tanks to settle, and the
clear liquor finally conveyed to the ordinary precipitating tanks, where
the bulk of the copper is thrown down in the usual way. A fresh
quantity of copper liquors is now sent to the round tub and the opera-
tion repeated until a considerable deposit has accumulated in the
settling tanks; this deposit contains the silver and gold originally in
solution together with copper, both in the metallic state and as
dichloride, and also metallic impurities in the solution and the impurities
of the reduced iron powder. The dichloride of copper is dissolved out
by means of hot or cold brine or hydrochloric acid, in both of which,
as is well known, the dichloride of copper is soluble. The residue is
finally sold for copper, silver, and gold, or it is specially treated by well-
known methods for the economical separation of the precious metals.

page_text: of our Lord One thousand eight hundred and seventy-one, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Frederic Claudet, Her special license
that I, the said Frederic Claudet, my executors, administrators, and
assigns, or such others as I, the said Frederic Claudet, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE SEPARATION OF SILVER AND OTHER METALS FROM COPPER ORES," upon
the condition (amongst others) that I, the said Frederic Claudet, my
executors or administrators, by an instrument in writing under my,
or their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Frederic Claudet, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, that is to say :—
In the humid treatment of burnt Spanish and Portuguese cupreous
pyrites and other similar ores the copper, as is well known, is precipitated
The iron used is either
from the liquors by means of metallic iron.
scrap iron or metallic iron in a finely divided state (sponge iron) made
expressly for the purpose. The small quantity of silver present in the
copper liquors is by the processes now employed precipitated along with
the copper, but the quantity is too small to admit of profitable separation
except in special cases, as when copper precipitate is employed for the
manufacture of sulphate of copper.
My Invention consists in separating the silver and gold previous to
the precipitation of the bulk of the copper, and concentrating the
precious metals in a comparatively small quantity of copper precipitate,
In order to reduce
which can then be advantageously dealt with.
the dissolved chloride of silver to the metallic state the protochloride
of copper in solution must first be transformed into dichloride of
copper, and when this is accomplished I find that a very slight addition

page_text: of finely divided iron immediately throws down the silver. To effect
the transformation of the protochloride of copper into dichloride it is
only necessary to add sufficient iron to combine with one half the
chlorine of the protochloride of copper present when dichloride of copper
and protochloride of iron are formed, according to the formula 2 Cu Cl
+ FeCu³ Cl + Fe Cl. When the copper occurs in the form of proto-
chloride this condition is best obtained by first ascertaining the quantity
of copper in solution and then adding by weight the calculated equivalent
of finely divided iron, a slight excess of which will then precipitate the
silver along with a little copper. When, on the contrary, the liquors
already contain a notable quantity of dichloride of copper, the amount
of finely divided iron to be added is best determined by shaking a
measured volume of the liquors in a bottle with an excess of finely
divided iron, so as to precipitate all the copper, and then ascertaining
after filtration the amount of iron in solution by the permanganate test.
One half the iron thus found will be the right proportion to ensure the
above reaction.
•
I now proceed as follows: -I first prepare finely divided iron by
heating in a retort or close furnace, as is well known, a suitable mixture
of finely ground oxide of iron, or purple orc and charcoal or coal, until
the oxide of iron is reduced to the metallic state. Precipitated oxide of
iron or rouge may be used for the same purpose with advantage. This
reduction should be made at a low red heat, as too high a temperature
tends to the aggregation of the metallic particles. After the reduced
iron has been brought to a fine state of division by further grinding it
is tested in order to ascertain the exact per-centage of pure iron it
contains. The copper liquors are now made to flow into a round vat or
tub of known capacity and supplied with revolving arms to keep the
liquors in motion. The quantity of copper in solution is next rapidly
determined by the cyanide of potassium test, or otherwise, and the
amount of iron necessary to convert the protochloride of copper into
dichloride is ascertained. A weighed quantity of finely divided iron is
now taken, containing from 1 to 5 per cent. more pure iron than the
quantity theoretically necessary, and is gradually introduced into the
copper solution by causing it to pass through a wire gauze sieve so as
to separate the particles as they fall into the liquid. The
solution
is kept constantly in motion, a considerable rise of temperature takes
place, and the copper is rapidly transformed into dichloride, which for
copper

page_text: the most part is held in solution by the alkaline and metallic chlorides
present. The reaction is complete when the solution from green becomes
nearly colorless. Agitation is continued for a few minutes, and then
the solution is run off into tanks to settle, and the clear liquor finally
conveyed to the ordinary precipitating tanks, where the bulk of the
copper is thrown down in the usual way. A fresh quantity of copper
liquors is now sent to the round tub and the operation repeated until a
considerable deposit has accumulated in the settling tanks. This deposit
contains the silver and gold originally in solution, together with copper,
both in the metallic state and as dichloride, and also metallic impurities
in the solution and the impurities of the reduced iron powder. The
dichloride of copper is dissolved out by means of hot or cold brine or
hydrochloric acid, in both of which, as is well known, the dichloride of
copper is soluble. The residue is finally sold for copper, silver, and
gold, or it is specially treated by well-known methods for the economical
separation of the precious metals.
Having thus described the nature of my Invention, and the manner
of performing the same, I would have it understood that what I claim
as my improvements in the separation of silver and other metals from
copper ores is, the separating silver and gold and metallic impurities
from the copper solution or liquors previous to the precipitation of the
bulk of the copper by adding to the solution finely divided iron powder,
care being taken to use but little more than is necessary to convert the
protochloride of copper in the solution into dichloride of copper, sub-
stantially as herein described.
In witness whereof, I, the said Frederic Claudet, have hereunto
set my hand and seal, this Twenty-third day of October, in
the year of our Lord One thousand eight hundred and seventy-
one