IMPROVEMENTS IN THE TREATMENT OF PYRITES FOR- THE MANUFACTURE OF IRON."
Year: 1861

page_text: LETTERS PATENT to Emile Cajot, Merchant, of St. Servais, Belgium,
for the Invention of "IMPROVEMENTS IN THE TREATMENT OF PYRITES FOR-
THE MANUFACTURE OF IRON."
PROVISIONAL SPECIFICATION left by the said Emile Cajot at the
Office of the Commissioners of Patents, with his Petition, on the 14th
December 1861.
I, EMILE CAJOT, Merchant, of St. Servais, Belgium,. do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN THE TREATMENT OF
PYRITES FOR THE MANUFACTURE OF IRON," to be as follows:-
The improvements relate to the combination of the residues of pyrites with
argillaceous earths, pulverized limestone or chalk in the manufacture of iron.
Till now the residues of pyrites proceeding from various chemical and other
processes have not been employed in a satisfactory and advantageous manner
in the production of iron on account of the quantity of sulphur which these
residues contain in relation to their metalliferous richness hastening the fusion,
and causing combinations which the greatest heat cannot again separate.
According to my improvements, I mix the residues of pyrites obtained with
other matters adapted to their proper fusion, and the mixture I employ
consists of argillaceous earths, pulverized limestone, or chalk in certain pro-
portions, these three matters conjointly or separately according to their
ascertained qualities being found favorable to the proper fusion of pyritous
residuum. Any or all of the matters referred to being mixed with pyritous
residuum, which has previously been reduced to powder, a paste is formed,.

page_text: which is moulded as required in the form of bricks or other suitable form.
The paste thus prepared may be operated with when dry, as when operating
with iron ore for the manufacture of iron; such paste will then contain no
more sulphur than the ordinary ores, and its fusion will be effected with so
much more facility in proportion as the particles of the pyrites have been
intimately combined with the matters above referred to. The proportions may be
varied considerably, depending upon the quantity of foreign matter the residue
may contain; but when pyrites as found in the province of Namur are used, I
find a mixture of from 700 to 800 parts of residue to 200 of clay to answer
well. The intimate mixture of the matters is obtained by the aid of water.
The bricks or other moulded forms obtained may be baked in kilns or other-
wise to bring them to a compact mass. When it is found that the residues
of pyrites still contain a considerable quantity of sulphur, such may be col-
lected by submitting the composite paste obtained as above explained, to
heat in a close furnace so as to cause the sulphur to pass off in the form
of vapour. The calcined paste deprived of its sulphur may then be treated as
when manipulating with ordinary iron ore.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Emile Cajot in the Great Seal Patent Office on the 13th
June 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EMILE
CAJOT, Merchant, of St. Servais, Belgium, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourteenth day of December, in the year of our
Lord One thousand eight hundred and sixty-one, in the twenty-fifth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Emile Cajot, Her special licence that I, the said Emile Cajot, my
executors, administrators, and assigns, or such others as I, the said Emile
Cajot, 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 PYRITES FOR THE MANUFACTURE OF IRON," upon the condition
(amongst others) that I, the said Emile Cajot, 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

page_text: 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 Emile Cajot, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:
The improvements relate to the manufacture of iron from the residues of
pyrites by the combination therewith of argillaceous earths, pulverized lime-
stone or chalk, separately or combined... Till now I believe the residues-of
pyrites proceeding from various chemical and other processes have not been
employed in a satisfactory and advantageous manner in the production of iron,
on account of the quantity of sulphur which these residues contain in relation
to their metalliferous richness hastening the fusion, and causing combinations
which very great heat does not again separate.
According to my improvements, I mix the residues of pyrites with other
matters adapted to their proper fusion. The matters I employ are argil-
laceous earths, pulverized limestone or chalk, and I employ them conjointly
or separately according as their ascertained qualities are found favourable to
the proper fusion of the pyritous residuum. I proceed as follows:-The
residue of pyrites having been reduced to powder, in order to facilitate the
disengagement of the sulphur and other foreign matters therefrom, I wash it
well in water, by preference still or stagnant, in order to avoid as much as
possible loss of mineral during the cleansing (the operation of washing,
however, is not indispensable). After settlement of the particles of pyrites
the water is allowed to run off, and I add to the mixture from 15 to 30 per
cent. of argillaceous earth according to the richness in iron of the pyritous
residuum under treatment, and add sufficient water to form a paste of a
suitable consistency, which may be moulded into the form of bricks or into
other forms desired, or be cut into blocks. The paste thus treated may be
left on the ground to dry, and when dry be submitted to heat to extract
the sulphur, or it may be submitted to heat without having been previously
dried.
The sulphur may be extracted from the bricks previous to their introduction
into the melting furnace by subjecting them to heat in an ordinary open air
brick kiln, or in a close furnace, or above the blast furnace to render the
waste heat of the same available. In the first method the heat is kept up for
five or six days; in the second (which I practise when I wish to collect the
sulphur contained in the prepared paste, which sulphur in some cases becomes

page_text: a source of considerable profit) the duration of the heat may be regulated as
necessary, but I find a roasting of from 36 to 48 hours to afford a good
result.
It is preferable not to use the bricks immediately after they have been
baked, in order that they may absorb the moisture of the air which makes
them give off during their fusion what little sulphur they may still contain.
The paste being now almost entirely deprived of its sulphur may be treated as
when operating with ordinary iron ore for the manufacture of iron, and will
be found to contain no more sulphur than the ordinary ores of iron, and
its fusion will be facilitated in proportion as the particles of pyrites have
been intimately combined by mixture with the argillaceous or other matters
referred to.
When the residues under treatment do not contain much sulphur, the
operation of baking or calcining the paste may be dispensed with, and the said
paste may be charged into the melting furnace as soon as it is dry. The pro-
portions of matters used as a mixture with the residues of pyrites may be
varied considerably, depending upon the quantity of foreign matter the residue
under operation may contain; but when pyrites as found in the province of
Namur are used, I find a mixture of from 700 to 800 parts of residue to 200
parts of clay to afford a good result.
Limestone or chalk may be added to the mixture of pyrites, residue, and
clay at the time of making the paste, but I prefer to add the said limestone
or chalk when the mineral is being melted in the melting furnace, as the
quantity of the said limestone can be then regulated as may be found desirable.
I have found a mixture made with the earths proceeding from the washing of
ordinary iron ores to give a good result.
Having thus described the nature of the said Invention, and the means by
which I carry the same into effect, I would have it understood that I do not
confine myself to the precise details referred to so long as the peculiar character
of the improvements be retained substantially as explained.
In witness whereof, I, the said Emile Cajot, have hereunto set my hand
and seal, this Tenth day of June, in the year of our Lord One
thousand eight hundred and sixty-two.