IMPROVEMENTS IN EXTRACTING COPPER AND SEVERAL OTHER METALS FROM CERTAIN ORES OF THESE METALS
Year: 1865

page_text: LETTERS PATENT to William Henderson, of the City of Glasgow, Chemist,
for the Invention of "IMPROVEMENTS IN EXTRACTING COPPER AND SEVERAL
OTHER METALS FROM CERTAIN ORES OF THESE METALS."
Sealed the 31st October 1865, and dated the 5th May 1865.
PROVISIONAL SPECIFICATION left by the said William Henderson at
the Office of the Commissioners of Patents, with his Petition, on the
5th May 1865.
I, WILLIAM HENDERSON, of the City of Glasgow, Chemist, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN EXTRACTING
COPPER AND SEVERAL OTHER METALS FROM CERTAIN ORES OF THESE METALS," to be
as follows:-
These improvements relate to means of obtaining in solution copper when
it exists in the states of oxide, carbonate, arseniate, or other salt of copper
associated with large proportions of silica or other substances insoluble in
dilute acids.
When oxides, carbonates, arseniates, or other salts of copper insoluble in
water are separated from their gangues by solution in muriatic acid, and the
copper afterwards precipitated from this solution by metallic iron, a solution
of protochloride of iron is obtained as a residual liquor, which has heretofore
been allowed to run to waste, or has been decomposed by evaporations to
dryness with sand, and repeatedly moistened as described in the Specification
of a Patent granted to me, Thirtieth September, One thousand eight hundred
and fifty-seven, No. 2517. I have, however, found that by treating the
FPrice 8d1

page_text: protochloride of iron in this manner a considerable proportion is decomposed
into chlorine and oxide of iron, and that the gaseous chlorine passes up
through the water and escapes from the tower uncondensed. I have also
found that the perchloride of iron has a strong solvent action on the oxides,
and the salts of copper insoluble in water, and that it readily dissolves copper
from ores of this class depositing peroxide of iron, and that by long contact
it decomposes and dissolves the red oxide and sulphurets of copper.
To convert the protochloride of iron into perchloride of iron, I adopt one or
other of the following methods, or I employ a combination of one or more of
these methods as circumstances permit:-1st, the protochloride liquor is
stirred up and agitated with a small proportion, say I lb. of finely powdered
peroxide of manganese to 100 gallons of liquor, and run out into shallow
ponds or vessels, and exposed to the air and sun; the liquor is afterwards
pumped up and repeatedly passed through walls or surfaces of thorns or
brushwood, as is well known and practised for the manufacture of salt from
poor brine springs, and is called graduation. The object, however, in this
case being as much oxidation as concentration, but both are secured by this
means, and it is found that a considerable portion of iron drops out of solution
as peroxide, and a red liquor remains after settling, which I return to the
dissolving tanks on to fresh copper ore; the metal is again readily dissolved,
and is again precipitated by metallic iron, and the resulting protochloride
solution oxidized as above described. 2nd, by long exposure to air in shallow
ponds, pits, or vessels, or by repeated exposure in a fine state of division, by
passing through the walls of thorns or surfaces of ropes in the graduation
process, the peroxidization of the iron may be effected, but the employment of
a small portion of peroxide of manganese very much facilitates the operation,
and consequently prefer to use it. 3rd, pump up the solutions so con-
centrated by graduation or evaporation to a reservoir or cistern over a lower
or condenser, which may be of stone or brick, as is used in chemical works
for condensing muriatic acid. I prefer to fill this tower with bricks or pebbles,
and use a second tower in conjunction therewith filled or partially filled with
coke. In connection with these towers or condensers I place one or more
reverberatory furnaces closed or open, preferring the former as more economical,
and using coke, wood, or other fuel that produces little smoke. In these
furnaces I place a certain portion of the copper ore rich in silica, and bring it
to a dull red heat; I then throw in by means of the pressure from the cisterns
on the top of the condensers, and through an iron pipe in connection there-
with a jet of the liquor, sprinkling it all over the hot ore in the furnace, and
thoroughly mixing and stirring the same. This I continue until in spite of

page_text: the heat of the furnace the whole of the ore becomes moist; I then stop and
bring the mixture again up to redness, when again drench it with proto-
chloride iron liquor, repeating the operation as long as the residne maintains
a sandy granular state; when it becomes powdery or sticky I remove the
residue, and if it has only been an ore of copper I place it in tanks with false
bottoms and wash with water, which will dissolve out all the copper. The
gases given off in this operation are muriatic acid, perchloride of iron, chlorine
and watery vapour; 1 pass them through flues or glazed pipes into and up
the tower containing bricks or pebbles, and down which a constant. stream or
concentrated solution of protochloride or mixture of proto and perchlorides of
iron is constantly descending. The stream is so regulated that the whole of
the ascending gases are either condensed or absorbed, and the protochloride
of iron issues at the base of the tower wholly or partially converted into per-
chloride of iron by the action of the chlorine and strongly acid by the
absorbtion of the muriatic acid. The gases that remain uncondensed are
passed down outside the first condenser by means of glazed pipes, and inserted
at the base of the second, and ascend through the coke, meeting there also a
descending shower of iron solution; a third or fourth condenser if necessary
may be employed to prevent waste, but I have found that two towers of fifty
fect each practically condense all useful gases.
I have also found it best to employ two furnaces for each set of condensing
apparatus injecting liquor into only one at a time, whilst the other is evaporating
to dryness and getting up heat. In the latter operation principally chlorine
is given off, and in the former muriatic acid.
When a strongly siliceous ore containing besides copper or other valuable
metal, such as cobalt or nickel, can be obtained containing also a proportion
of manganese, I prefer to employ it in the decomposing furnace.
I then
finish the decompositions by weak solutions, and at last with water; by this
means I get rid of all the soluble salts of iron, and nearly all the manganese,
and when the dry powder is withdrawn from the furnace and lixiviated, the
undecomposed salts of copper, cobalt, and nickel will be found in solution,
and are separated in the usual way. The strongly acid perchloride of iron is
used (as muriatic acid was in the first instance) for dissolving copper or other
metal from fresh ore, the solution from this is again reduced by metallic iron,
and again oxidized and used over and over again, the natural waste being
made up with fresh acid or by adding common salt to the decomposing
furnaces.
The natural persulphates of iron containing copper also in solution, as
pumped from certain mines, or as produced in heaps on the surface of certain

page_text: mines, have been found very destructive to iron. It has been found in
practice that in many instances three, four, and often ten tons of metallic iron
are required to produce a ton of copper from these liquors. this is entirely
owing to the presence of persulphate of iron, these liquors might be con-
sidreably deoxidized by passing them through several times a stratum of burnt
coppery pyrites, and they will without any acid or other assistance extract the
whole of the copper from these ores. and he then reduced at a much smaller
expenditure of iron; or they may be repeatedly passed through or kept in
contact for a considerable time with peat or other matter capable of yielding
organic acids.
SPECIFICATION
in pursuance of the conditions of the Letters Pateni, filed
by the said William Henderson in the Great Seal Patent Office on the
4th November 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HENDERSON, of the City of Glasgow, Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of May, in the year of our Lord One
thousand eight hundred and sixty-five, in the twenty-eighth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Henderson. Her special licence that I, the said William
Henderson, my executors, administrators, and assigns, or such others as I,
the said William Henderson, 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,
usc. exercise, and vend, within the United Kingdom of Great Britain and
Treland, the Channel Islands, and Isle of Man, an Invention for "IMPROVE.
MENTS IN EXTRACTING COPPER AND SEVERAL OTHER METALS FROM CERTAIN ORES OF
THESE METALS, upon the condition (amongst others) that 1. the said William
Henderson, 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 Ị. the said William Henderson, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-

page_text: formed. to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
These improvements relate to means of obtaining in solution copper when
it exists in the states of oxide, carbonate, arseniate. or other salt of copper
associated with large proportions of silica or other substances insoluble in
dilute acids.
When oxides, carbonates, arseniales, or other salts of copper insoluble in
water are separated from their gangues by solution in muriatic acid, and the
copper afterwards precipitated from this solution by metallic iron, a solution
of protochloride of iron is obtained as a residual liquor which has heretofore
been allowed to run to waste, or has been decomposed by evaporation to
dryness with sand and repeatedly moistened, as described in the Specification
of a Patent granted to me 30 September 1857. No. 2517. I have, how-
ever, found that by treating the protochloride of iron in this manner a con-
siderable proportion is decomposed into chlorine and oxide of iron, and that
the gaseous chlorine passes up through the water and escapes from the tower
uncondensed. I have also found that the perchloride of iron has a strong
solvent action on the oxides, and the salts of copper insoluble in water, and
that it readily dissolves copper from ores of this class depositing peroxide of
iron, and that by long contact it decomposes and dissolves the red oxide and
sulphurets of copper.
To convert the protochloride of iron into perchloride of iron. I adopt one or
other of the following methods, or I employ a combination of one or more of
these methods as circumstances permit:-First, the protochloride liquor is
stirred up and agitated with a small proportion, say 1 lb. of finely powdered
peroxide of manganese to 100 gallons of liquor, and run out into shallow ponds
or vessels, and exposed to the air and sun; the liquor is afterwards pumped
up and repeatedly passed through walls or surfaces of thorns or brushwood,
as is well known and practised for the manufacture of salt from poor brine
springs, and is called graduation. The object. however, in this case is as
much oxidation as concentration, but both are secured by this means, and it
is found that a considerable portion of iron drops out of solution as peroxide,
and a red liquor remains after settling, which I return to the dissolving tanks
to fresh copper ore, the metal is again readily dissolved and
is again precipitated by metallic iron. and the resulting protochloride solutions
oxidized as above described. Second, by long exposure to air in shallow
ponds, pits, or vessels, or by repeated exposure in a fine state of division, by
passing through the walls of thorns or surfaces of ropes in the graduation
process, the peroxidization of the iron may be effected, but the employment
on

page_text: of a small portion of peroxide of manganese very much facilitates the opera-
tion, and consequently prefer to
use it. Third, pump up the
solutions so concentrated by graduation or evaporation to a reservoir or cistern
over a tower or condenser, which may be of stone or brick, as is used in
chemical works for condensing muriatic acid. I prefer to fill this tower with
bricks or pebbles, and use a second tower in conjunction therewith, filled or
partially filled with coke. In connection with these towers or condensers I
place one or more reverberatory furnaces close or open, preferring the latter
as more economical, and using coke, wood, or other fuel that produces little
smoke.
In these furnaces I place a certain portion of the copper ore rich in silica,
and bring it to a dull red heat; I then throw in by means of the pressure from
the cisterns on the top of the condensers, and through an iron pipe in con-
nection therewith, a jet of the liquor, sprinkling it all over the hot ore in the
furnace, and thoroughly mixing and stirring the same. This I continue until,
in spite of the heat of the furnace, the whole of the ore becomes
moist; I then stop and bring the mixture again up to redness, when
I again drench it with protochloride iron liquor, repeating the operation as long
as the residue maintains a sandy granular state; when it becomes powdery
or stickey I remove the residue, and if it has only been an ore of copper I
place it in tanks with false bottoms, and wash with water which will dissolve
out all the copper. The gases given off in this operation are muriatic acid,
perchloride of iron, chlorine, and watery vapour; I pass them through flues or
glazed pipes into and up the tower containing bricks or pebbles, and down
which a constant stream of concentrated solution of protochloride or mixture
of proto and perchlorides of iron is constantly descending. The stream is so
regulated that the whole of the ascending gases are either condensed or
absorbed, and the protochloride of iron issues at the base of the tower wholly
or partially converted into perchloride of iron by the action of the chlorine
and strongly acid by the absorption of the muriatic acid. The gases that
remain uncondensed are passed down outside the first condenser by means of
glazed pipes, and inserted at the base of the second and ascend through the
coke, meeting there also a descending shower of iron solution; a third or fourth
condenser if necessary may be employed to prevent waste, but I have found
that two towers of 50 feet each practically condense all useful gases. I have
also found it best to employ two furnaces for each set of condensing apparatus
injecting liquor into only one at a time, whilst the other is evaporating to
dryness and getting up heat. In the latter operation principally chlorine is
given off, and in the former muriatic acid.

page_text: When a strongly siliceous ore containing besides copper or other valuable
metal, such as cobalt or nickel, can be obtained, containing also a proportion
of manganese, I prefer to employ it in the decomposing furnace. I then
finish the decompositions by weak solutions, and at last with water, by this
means I get rid of all the soluble salts of iron and nearly all the manganesc,
and when the dry powder is withdrawn from the furnace and lixiviated the
undecomposed salts of copper, cobalt, and nickel will be found in solution,
and are separated in the usual way. The strongly acid perchloride of iron is
used (as muriatic acid was in the first instance) for dissolving copper or other
metal from fresh ore, the solution from this is again reduced by metallic iron
and again oxidized and used over and over again, the natural waste being
made up with fresh acid, or by adding common salt to the decomposing
furnaces.
The natural persulphates of iron containing copper also in solution as
pumped from certain mines, or as produced in little heaps on the surface of
certain mines have been found very destructive to iron. It has been found in
practice that in many instances three, four, and often ten tons of metallic iron
are required to produce a ton of copper from these liquors; this is entirely
owing to the presence of persulphate of iron; these liquors might be con-
siderably deoxidized by passing them through several times a stratum of
burnt coppery pyrites, and they will without any acid or other assistance
extract the whole of the copper from these ores, and be then reduced at a
much smaller expenditure of iron. Or they may be repeatedly passed through
or kept in contact for a considerable time with peat or other matter capable
of yielding organic acids.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I claim extracting copper
and several other metals from certain ores of these metals by the means and
in manner herein-before described.
In witness whereof, I, the said William Henderson, have hereunto set
my hand and seal, this Third day of November. One thousand eight
hundred and sixty-five.
W. HENDERSON. (L.S.)