IMPROVEMENTS IN TREATING THE RESIDUES OF PYRITES USUALLY CALLED BURNED ORES
Year: 1866

page_text: LETTERS PATENT to Warren De La Rue, of Bunhill Row, and Hugo
Müller, of No. 79, Gower Street, both in the County of Middlesex, for
the Invention of "IMPROVEMENTS IN TREATING THE RESIDUES OF PYRITES
USUALLY CALLED BURNED ORES."
Sealed the 6th October 1866, and dated the 15th May 1866.
PROVISIONAL SPECIFICATION left by the said Warren De La Rue and
Hugo Müller at the Office of the Commissioners of Patents, with their
Petition, on the 15th May 1866.
We, WARREN DE LA RUE, of Bunhill Row, and HUGO MULLER; of No. 79,
Gower Street, both in the County of Middlesex, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN TREATING THE RESIDUES OF PYRITES
USUALLY CALLED BURNED ORES," to be as follows:-.
This Invention has for its object improvements in treating the residues of
pyrites, usually called burned ores, in order to separate copper and silver if
present from the oxide of iron in the residues. These residues are ground or
reduced to a fine powder, and are wetted or mixed with sulphuric acid, and
the mixture which has the property of setting is moulded or formed into
blocks or lumps which are subjected to heat in a furnace, the temperature
being raised sufficiently to decompose sulphate of iron and leave the sulphates
of copper and silver undecomposed. By these means the copper and the
silver are for the most part rendered soluble in water, whilst the iron is for

page_text: the most part left insoluble in water; the copper and silver are then separated
from the iron by water, and the copper and silver are separated by deposition
from the solution in the ordinary manner.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Warren De La Rue and Hugo Müller in the Great Seal Patent
Office on the 15th November 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WARREN
DE LA RUB, of Bunhill Row, and HUGO MÜLLER, of No. 79, Gower Street,
both in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifteenth day of May; in the year of our Lord One
thousand eight hundred and sixty-six, in the twenty-ninth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto us, the said
Warren De La Rue and Hugo Müller, Her special licence that we, the said
Warren De La Rue and Hugo Müller, our executors, administrators, and
assigns, or such others as we, the said Warren De La Rue and Hugo Müller,
our 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 TREATING THE
RESIDUES OF PYRITES USUALLY CALLED BURNED ORES," upon the condition
(amongst others) that we, the said Warren De La Rue and Hugo Müller, our
executors or administrators, by an instrument in writing under our or their
hands and seals, or under the hand and seal of one of us or them, 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Hugo Müller, on behalf of myself and
the said Warren De La Rue, do hereby declare the nature of the said Inven-
tion, 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 improvements in treating the residues of
pyrites, usually called burned ores, in order to separate copper and silver if

page_text: present from the oxide of iron in the residues. These residues are ground or
reduced to a fine powder, and are wetted or mixed with sulphuric acid, and
the mixture which has the property of setting is moulded or formed into blocks
or lumps which are subjected to heat in a furnace, the temperature being
raised sufficiently to decompose sulphate of iron and leave the sulphates of
copper and silver undecomposed. By these means the copper and the silver.
are for the most part rendered soluble in water, whilst the iron is for the most
part left insoluble in water; the copper and silver are then separated from
the iron by water, and the copper and silver are separated by deposition from
the solution in the ordinary manner.
Having thus stated the nature of our said Invention we will proceed more
fully to describe the manner of performing the same.
According to the nature of the ore and the means employed in burning it
the residue consists of a more or less homogeneous mixture of oxide of iron,
oxide of copper, sulphide of iron, and sulphide of copper.
.
In order to facilitate the operation it is necessary that the material is in
the state of powder, and may for this purpose be ground under ordinary edge
runners or otherwise; the powder is then mixed with dilute sulphuric acid,
and exposed to red heat, either formed in the shape of bricks or blocks, and
burnt in a kiln, or in the state of powder in an ordinary calciner, or in a
muffle furnace. If the former process is adopted it is essential that all the
iron contained should be in the state of oxide, and the copper likewise in &
state of oxide or nearly so, otherwise a considerable quantity of sulphuric acid
will be required to oxidize the sulphides.
If the operation of burning is carried on in a reverberatory furnace it is of
less importance that the ore should be previously so completely oxidized,
inasmuch as oxidation then takes place at the expense of the atmospheric air,
and the operation then may be carried on in such a way that at the beginning
of the process the sulphides become oxidized to sulphates; towards the end the
heat is increased in order to decompose the sulphate of iron; the product
obtained in these processes of burning with sulphuric acid is then extracted
with water until the soluble sulphate of copper is removed; the solution is
then allowed to remain in contact with metallic iron, which precipitates the
copper in the metallic state. Should the ore contain silver, as sometimes
happens, this metal would likewise pass into solution, and may be removed
therefrom by the introduction into the solution of metallic copper previous to
the precipitation of the copper by means of iron.
.
The quantity of sulphuric acid used for this process depends on the quantity
of copper present, and also on the state of the burnt ore. If it still contains

page_text: sulphides, a proportionate quantity of acid is required to oxidize the sulphur
and the metal combined with it. Under all circumstances it is advantageous
to employ an excess of acid.
It has been found that for the purpose of making the bricks it is sufficient
to mix the quantity of strong acid which analysis shows to be necessary to
combine with the copper and silver with so much water as is necessary to
obtain a plastic mass with the ground residues which can thus be formed with
the ordinary means employed for this purpose; shortly after the mixture is
made the mass becomes firmer, and can be moulded into any required form ;
shortly it sets, and can then be handled and dried previous to being burnt.
In witness whereof, I, the said Hugo Müller, have hereunto set my hand
and seal, this Fourteenth day of November, in the year of our Lord
One thousand eight hundred and sixty-six.
HUGO MÜLLER. (L.S.)