Im- PROVEMENTS IN THE EXTRACTION OF METALS FROM THEIR ORES."
Year: 1874

page_text: LETTERS PATENT to Stephen Henry Emmens, of 8, Old Jewry, in
the City of London, Scientific Referce, for the Invention of "Im-
PROVEMENTS IN THE EXTRACTION OF METALS FROM THEIR ORES."
PROVISIONAL SPECIFICATION left by the said Stephon Henry
Emmens at the Office of the Commissioners of Patents, with his
Petition, on the 20th October 1874.
I, STEPHEN HENRY EMMENS, of 8, Old Jewry, in the City of London,
Scientific Referee, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE EXTRACTION OF METALS FROM THEIR ORES," to be as
follows:-
The object of my Invention is to facilitate the extraction of metals
from their ores by improvements in what are known as
"wet processes."
These processes generally consist of three-stages, viz., first roasting with
or without salt so as to oxidize or chloridize the ore; secondly, lixiviating
with water acid or brine so as to wash out the soluble metals; and

page_text: thirdly, precipitating the dissolved metals from their solutions. In some
cases the first stage is omitted.
The improvements that I have discovered are applicable to the several
stages, and their nature is as follows:-In the roasting stage I add to
the ore (either mixed or not mixed with salt) a quantity of fluor spar or
other fluoride sufficient to fluoridize the metal or metals desired to be
thus extracted, which may be easily calculated by a preliminary assay,
and to this mixture I add in cases where the ore does not contain sulphur
a sufficient quantity of sulphur or metallic sulphides to decompose the
fluoridizing agent employed.
In the lixiviating stage I add to the ore (whether roasted with or
without chloridizing or fluoridizing agents or not roasted at all) a solution
of salt or saltpetre, or salt and saltpetre with the further addition of
sufficient sulphuric acid to evolve enough hydrochloric acid or nitric acid,
or hydrochloric and nitric acids to render soluble any metals desired to
be extractod, and which were not previously in a soluble condition.
In the precipitating-stage I cause the liquor from the lixiviating vat
to pass over iron pyrites or other metallic sulphides with the view of
precipitating gold and silver, and in some cases I add a solution of
ferrous sulphate for the purpose of accelerating such precipitation. The
liquor is then passed over metallic copper, zinc, and iron, or any one or
two of those metals for the purpose of further precipitating the metals
held in solution, and is then ready for treatment with an alkali so as
finally to precipitate any remaining metals, after which it can be con-
centrated or evaporated to dryness so as to recover the saline substances
with which it is charged.
The various reactions I find can be much accelerated and improved
by the application of heat to the liquor during the lixiviating and
precipitating stage, and the most convenient way of doing this is to
employ a jet of free steam.
It is obvious that my Invention above described can be employed

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Stephen Henry Emmens in the Great Seal
Patent Office on the 20th April 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, STEPHEN
HENRY EMMENS, of 8, Old Jowry, in the City of London, Scientific
Referee, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twentieth day of October, in the year
of our Lord One thousand eight hundred and seventy-four, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Stephen Henry Emmens, Her special
licence, that I, the said Stephen Henry Emmens, my executors,
administrators, and assigns, or such others as I, the said Stephen
Henry Emmens, 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 EXTRACTION OF METALS FROM THEIR
ORES," upon the condition (amongst others) that I, the said Stephen
Henry Emmens, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should par-
ticularly 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 Stephen Henry Emmens, do
hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained in and by the following statement thereof, that is to say:―
The object of my Invention is to facilitate the extraction of metals
"wet processes."
from their ores by improvements in what are known as
These processes generally consist of three stages, viz., first roasting with
or without salt so as to oxidize or chloridize the ore; secondly, lixiviating
out the soluble matale: and

page_text: thirdly, precipitating the dissolved metals from their solutions. In
some cases the first stage is omitted.
The improvements that I have discovered are applicable to the several
stages and their nature, is as follows:-In the roasting stage I add to the
ore (either mixed or not mixed with salt) a quantity of fluor spar or
other fluoride sufficient to fluoridize the metal or metals desired to be
thus extracted, which may be easily calculated by a preliminary assay,
and to this mixture I add in cases where the ore does not contain
sulphur a sufficient quantity of sulphur or metallic sulphides to de-
compose the fluoridizing agent employed.
In the lixiviating stage I add to the orc (whether roasted with or
without chloridizing or fluoridizing agents or not roasted at all a solution
of salt or saltpetre, or salt and saltpetre with the further addition of
sufficient sulphuric acid to evolve enough hydrochloric acid or nitric
acid, or. hydrochloric and nitric acids to render soluble any metals
desired to be extracted, and which were not previously in a soluble
condition.
In the precipitating stage I cause the liquor from the lixiviating vat
to pass over iron pyrites or other metallic sulphides with the view of
precipitating gold and silver, and in some cases I add a solution of
ferrous sulphate for the purpose of accelerating such precipitation. The
liquor is then passed over metallic copper, zinc, and iron, or any one or
two of those metals for the purpose of further precipitating the metals
held in solution, and is then ready for treatment with an alkali so as
finally to precipitate any remaining metals, after which it can be con-
centrated or evaporated to dryness so as to recover the salino substances
with which it is charged.
The various reactions I find can be much accelerated and improved
by the application of heat to the liquor during the lixiviating and pre-
cipitating stages, and the most convenient way of doing this is to employ
a jet of free stcam.
It is obvious that my Invention above described can be employed
either wholly or in part.
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,―
The treatment of metallic ores in the manner described for the purpose
of extracting the metal or metals therefrom.

page_text: Secondly. I claim the modified treatment or process, as set forth, for
thic extraction of metals from their ores.
•
In witness whereof, I, the said Stephen Henry Emmens, have
hereunto set my hand and seal, this Nineteenth day of April,
One thousand eight hundred and seventy-five.
STEPHEN H. EMMENS. (L.S.)