IMPROVEMENTS IN THE TREATMENT OF BURNT CUPREOUS PYRITES FOR THE EXTRACTION OF THE METALS CONTAINED THEREIN
Year: 1869

page_text: LETTERS PATENT to William Wright, of Mostyn, in the County of
Flint, for the Invention of "IMPROVEMENTS IN THE TREATMENT OF
BURNT CUPREOUS PYRITES FOR THE EXTRACTION OF THE METALS CONTAINED
THEREIN."
Sealed the 15th February 1870, and dated the 4th September 1869.
PROVISIONAL SPECIFICATION left by the said William Wright at the
Office of the Commissioners of Patents, with his Petition, on the
4th September 1869.
I, WILLIAM WRIGHT, of Mostyn, in the County of Flint, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN THE
TREATMENT OF BURNT CUPREOUS PYRITES FOR THE EXTRACTION OF THE METALS
CONTAINED THEREIN," to be as follows:-
This Invention has for its object the recovery of the lead and silver
contained in burnt cupreous pyrites. For this purpose I first extract
the copper by roasting, either with or without salt and subsequent
lixiviation. When salt is used for the extraction of the copper the greater
part of the lead remains behind in the iron residues in the state of

page_text: sulphate together with a little silver, whilst the largest portion of the
silver is dissolved out with the copper together with a little lead, and is
precipitated along with the copper by means of iron.
I operate as follows:-
First. I wash the iron residues or "purple ore" with a strong solution
of salt (brine), either hot or cold, which readily dissolves the sulphate of
lead and the silver. The lead and silver are precipitated by any of
the well-known means. I prefer using for this purpose a solution of
sulphide of sodium, taking care not to add an excess, so as to be able to
use the brine over and over again until it gets too highly charged with
sulphate of soda.
When in addition to the lead and the silver the brine washes out
copper, which is generally the case, this metal is precipitated with the
silver by scrap iron previous to the addition of sulphide of sodium, which
then throws down the lead and a little iron. After this treatment I find
the "
'purple ore or oxide of iron is not only free from lead and silver,
but generally much improved in quality and consequently in a condition
better suited for the purpose of iron making. The purification of the
purple ore by means of brine is part of this Invention.
"
Second. To obtain the silver and lead contained in the copper
precipitate it is first converted into black oxide of copper at a very low
temperature, so as to avoid as much as possible any volatilization of the
metals, and subsequently a small quantity of common salt is added,
either alone or mixed with sulphate of iron, in order to ensure the com-
plete transformation of the silver into chloride; I now wash with brine
and precipitate the silver and lead as previously described. When the
wet extraction is conducted without salt, that is, by converting the
copper into soluble sulphate by roasting and subsequent lixiviating, all
the lead and silver is in the iron residues, which are then treated with
brine.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourth day of September, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said William Wright, Her special licence that
I, the said William Wright, my executors, administrators, and assigns, or
such others as I, the said William Wright, 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 TREATMENT OF
BURNT CUPREOUS PYRITES FOR THE EXTRACTION OF THE METALS CONTAINED," upon
the condition (amongst others) that I, the said William Wright, 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 William Wright, 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 :-
This Invention has for its object the recovery of the lead and silver
contained in burnt cupreous pyrites. For this purpose I first extract
the copper by roasting either with or without salt and subsequent
lixiviation. Both these methods for obtaining copper from such ore are
well understood. When salt is used for the extraction of the copper
the greater part of the lead remains behind in the iron residues or
"purple ores" (that is to say, in the ores from which the copper has
been dissolved) in the state of sulphate, together with a little silver,
whilst the largest portion of the silver is dissolved out with the copper
together with a little lead, and is precipitated along with the copper by
means of iron. When the extraction is conducted without salt, that is,
by converting the copper into soluble sulphate by roasting the burnt
cupreous pyrites in the furnace without salt, or when hydrochloric acid
is added in lieu of salt before the orc goes into the furnace, and when

page_text: by subsequent. lixiviation the copper is dissolved out, practically all the
lead and silver remains in the iron residues.
In either case I operate as follows:-I wash the iron residues or
"purple ore" with a strong solution of salt (brine), either hot or cold,
which readily dissolves the sulphate of lead and the silver. The lead
and silver are precipitated from the brine by any of the well-known
means. I prefer using for this purpose a solution of sulphide of sodium
or milk of lime, taking care not to add an excess, so as to be able to
use the brine over and over again after being resaturated with salt until
it gets too foul.
When in addition to the lead and silver the brine washes out copper,
which is generally the case, this metal is precipitated with some of the
silver by scrap iron previous to the addition of sulphide of sodium or
milk of lime, which then throws down the lead and a little iron. After
this treatment I find the "purple ore" or oxide of iron is not only free
from lead and silver, but generally much improved in quality, and
consequently in a condition better suited for the purpose of iron
making.
6
I claim the extraction of lead and silver from the iron residues or
purple ore" obtained in the treatment of burnt cupreous pyrites by
means of brine, substantially as above described.
I also claim the purification of the iron residues or "purple ore" by
means of brine, substantially as above described.
Second. To obtain the silver and lead contained in the copper
precipitate it is first converted into Black oxide of copper by treating
it in a reverberatory furnace at a very low temperature, so as to avoid as
much as possible any volatilization of the metals, and with the same
object a little lime is added. Subsequently or shortly before the
removal of the charge from the furnace a small quantity of common
salt is added, either alone or mixed with sulphate of iron, in order to
insure the complete transformation of the silver into chloride. I now
wash with brine and precipitate the silver and lead as previously
described.
I claim as respects this part of my Invention the extraction of silver
and lead from the copper precipitate obtained by the treatment of
burnt cupreous pyrites by oxidizing such precipitated copper, and

page_text: further treating it and dissolving out the silver and lead with brine,
substantially as above described.
In witness whereof, I, the said William Wright, have hereunto set
my hand and seal, this Twenty-sixth day of February, in the
year of our Lord One thousand eight hundred and seventy.
WILLIAM WRIGHT. (L.S.)