IMPROVEMENTS IN ROASTING PYRITES AND IN APPARATUS FOR THE SAME; APPLICABLE ALSO TO THE TREATMENT OF OTHER SULPHURETS OF METAL
Year: 1871

page_text: of "IMPROVEMENTS IN ROASTING PYRITES AND IN APPARATUS FOR THE
SAME; APPLICABLE ALSO TO THE TREATMENT OF OTHER SULPHURETS OF METAL."
-A communication from abroad by Messieurs Perret Brothers and
Olivier, of Paris, France, Manufacturers.
Sealed the 21st November 1871, and dated the 11th July 1871.
PROVISIONAL SPECIFICATION left by the said William Spence at
the Office of the Commissioners of Patents, with his Petition, on
the 11th July 1871.
t
I, WILLIAM SPENCE, of 8, Quality Court, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN ROASTING PYRITES AND IN APPARATUS
FOR THE SAME; APPLICABLE ALSO TO THE TREATMENT OF OTHER SULPHURETS OF
METAL," (being a communication to me from abroad by Messrs.

page_text: Perret Brothers & Olivier, of Paris, France, Manufacturers, to be as
follows:-
This Invention has for its object the treating again of pyrites already
roasted in such a manner as to drive out as much as possible the
remaining portions of sulphur, and thus to bring it into a condition
suitable for the extraction of the metal. For this purpose the material
which has been already roasted is submitted to a further roasting in a
furnace composed of a body or lower part with compartments above it
suitably arranged in order to obtain an effect from the heat given out in
the burning of the material in the first process.
This end may be attained in various ways. In the first place, over a
furnace body in which is burned pyrites in pieces there is a series of
compartments formed by slabs of fire-clay, between which the heated
gases circulate in rising from the lower furnace. On each of these slabs
or floors is spread in a thin layer dust of pyrites, which burns thus
without being stirred from twenty-four. to thirty-six hours at most. By
means of this arrangement of the furnaces is effected a second roasting
of material aided by the heat given out by the first roasting.
A second mode of obtaining the result might be by substituting for
the one furnace in which the several floors are alternately charged with
crude and roasted material, distinct furnaces contiguously placed so as
to allow the heat to pass from one to the otlier, thereby establishing
a sort of calorific communication, the action of which is sufficiently
intense to cause the material to be repeatedly roasted. The furnaces or
compartments are arranged in an uneven number in one mass of brick-
work, in order that cach of them may contain alternately crude and
roasted material.
And another mode of operation is by means of an arrangement of
furnace in floors with the material introduced at the top and descending
from floor to floor and taken out burnt at the bottom.
In this case
stirring would be required, and it is to be observed that the Invention
relates to the treatment of the material whether stagnant or in a state
of agitation. It is likewise to be observed that the material in its
motion by descent is not only exposed to the effect of the heat developed
in the furnace by the crude pyrites burnt therein alternatively, but it
is also besides exposed to the heating action of the ore in pieces which
is burnt on the grate, and which supplies the heat necessary for again
roasting the impoverished material.

page_text: This placing of a furnace adapted for descending material over a
furnace with an undivided body is a distinctive feature of the Invention,
whether the furnace for descending material be charged with roasted or
with crude material. And the adaptation of the furnace with an
undivided body to a furnace with separate floors is a characteristic of
the Invention, whether it be made to operate on material stagnant or
quiescent on the floors, or on material descending from one floor on
to another; also on material either crude or alternated with material
already roasted.
modes of onenation hove referred to are applicable to the
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Spence in the Great Seal Patent Office
on the 11th January 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
SPENCE, of 8, Quality Court, Chancery Lane, in the County of Middle-
sex, Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of July, in the year of
our Lord One thousand eight hundred and seventy-one, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Spence, Her special licence
that I, the said William Spence, my executors, administrators, and
assigns, or such others as I, the said William Spence, 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, excrcise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
ROASTING PYRITES, AND IN APPARATUS FOR THE SAME; APPLICABLE ALSO TO THE
TREATMENT OF OTHER SULPHURETS OF METAL," (being a communication to
me from abroad by Messieurs Perret Brothers and Olivier, of Paris,
France, Manufacturers,) upon the condition (amongst others) that I,
the said William Spence, my executors or administrators, by an instru-
ment in writing under , or their, or one of their hands and seals,

page_text: 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 Scal 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 Spence, 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, reference being had to the Drawings hereunto
annexed, and to the letters and figures marked thereon (that is to
say):
This Invention has for its object the treating again of pyrites already
roasted in such a manner as to drive out as much as possible the
remaining portions of sulphur, and thus to bring it into a condition
suitable for the extraction of the metal, and to utilize all the sulphur
obtained by this new treatment. For this purpose the material which
has been already roasted is submitted to a further roasting in a furnace
composed of a body or furnace with compartments above it suitably
arranged in order to obtain an effect from the heat given out in the
burning of the material in the first process.
This end may be attained in various ways. In the first place, over a
furnace body in which is burned pyrites in pieces there is a series of
compartments formed by slabs of fire-clay, between which the heated
gases circulate in rising from the lower furnace. On each of these slabs
or floors is spread in a thin layer dust of pyrites, which burns thus
without being stirred from twenty-four to thirty-six hours at most. By
means of this arrangement of the furnaces is effected a second roasting
of material aided by the heat given out by the first roasting.
A second mode of obtaining the result might be by substituting for
the one furnace in which the several floors are alternately charged with
crude and roasted material, distinct furnaces contiguously placed so as
to allow the heat to pass from one to the other, thereby establishing a
sort of calorific communication, the action of which is sufficiently intense
to cause the material to be repeatedly roasted. The furnaces or com-
partments are arranged in an uneven number in one mass of brickwork,
in order that each of them may contain alternately crude and roasted
material.

page_text: partments are in section taken at the same place on the line 3, 4, in
order to shew the floors at E, E. The fifth compartment has the section
taken near the bottom in the line 5-6, 7-8, and shews the extremity of
the floors E and the flue B by which is established the communication
of the fire-place with the chambers.
Fig. 2 is a longitudinal vertical section of one of the compartments.
In this Figure will be seen besides the parts already mentioned the
fire-place D and the hole or outlet F in front of the brickwork, which is
covered by the two plates p and p¹. At O is a moveable stirrer, which
serves to cause the gases to pass through all the floors before reaching
the flue B.
Fig. 3 is a horizontal section taken on the line 9, 10. It will be seen
that the closing of the front of the furnace is effected by means of a
serics of plates A' alternating with plates A all bolted together. Also in
this Figure and in Fig. 2 it will be seen that the mouths of the floors
are closed by a double stopper, one part a of metal and the other a¹ of
fire-clay.
Fig. 2 shews at Q a space limited by the plates p" and p into which
the materials fall that are withdrawn from the floors.
Let it be supposed that it is required to effect the roasting over again.
of ore already desulphuretted in part by the former roasting. For this
purpose it will be sufficient to charge the compartments alternately with
crude and roasted ore as follows:-
First
Second
Third
Fourth
Fifth
compartment, compartment, compartment, compartment, compartment,
crude,
roasted,
crude,
roasted,
crude,
At the next operation they will be as follows :-
Second
Third
Fourth
Fifth
First
compartment, compartment, compartment, compartment, compartment,
crude,
roasted,
crude,
roasted,
roasted,
and so forth. It is to be observed that in these compartments the
surface presented by each floor is considerably more than that of the
fire-place. This arrangement is indispensable, as the floors are required
for roasting over again the material that has been once roasted and is
contained in the whole furnace, that is to say, both in the thinner layer
in the chambers or floors and the greater depth of material in the body
or fire-place. This material before being introduced on to the floors

page_text: to submit it to the further roasting ought to be broken into pieces of
convenient size.
In the operation as just described the ore remains where placed until
the end of the further roasting, but it is to be understood that the same
furnace may be employed in making the material fall from one floor on
to another, and pass out further roasted at the bottom of the floors of
the furnace. Thus the ore is withdrawn from the bottom floor, and it
is caused to fall into the enclosure Q. This enclosure can be emptied
by raising the plate p" which forms its front. When this is done the
material is withdrawn from the second floor and spread on to the first.
In order to make the material of the third floor pass on to the second it is
enough to push it from front to back, and it falls in the direction shewn
by the arrow f through holes formed on each side of the bottom at the
end of the floor for the passage of the gases. It is then spread on the
second floor. The passage of the material from the fourth floor on to
the third is effected by drawing it from back to front. Lastly, the fourth
floor is charged with fresh material.
That which constitutes the novelty of this furnace is, as hercin-before
stated, that the material is submitted not only to the heat developed
in the chambers or floors by the alternated crude material, but also to
the heat from the body or fire-place which is always charged with crude
material.
The furnace above described is only one of the arrangements that may
be adopted for obtaining the further roasting.
It is obvious that many others may be employed producing in every
case as a result the further roasting of the material once roasted by
means of the heat developed in the roasting of the crude material. It
is thus that furnaces can be used in which the ore is in motion instead
of being at rest.
By means of the process of further roasting, herein-before described,
the ordinary insufficient roasting involving a loss of the material sought
by the manufacturer of sulphuric acid is obviated, and all the sulphur
is utilized for the purpose.
The furnace is or may be arranged so as to adapt it for working
according to either of the two processes described, that is to say, either
that in which the further roasting may be performed at one operation,
leaving the material on the floors until the end of the operation, or in a

page_text: progressive manner, by making it fall from one floor on to the other,
until it is taken out roasted at the bottom of the furnace.
Having thus described the nature of the said Invention, com-
municated to me from abroad as aforesaid, and in what manner the
same is to be performed, I would remark that the features of novelty
and the advantages secured by the said Invention may be stated as
follows:-
The elimination of the last portions of sulphur contained in metallic
pyrites already roasted or once roasted, so as to convert them into
pyrites further roasted by means of the heat produced by the burning
of crude pyrites.
Useful effects produced in the condensation of sulphuric acid by the
more precise limitation of the quantity of air necessary for the apparatus.
The limitation rendered possible by the quantity of air absorbed
during the cooling of the material rendered porous by the first roasting.
The realization of this improvement by the introduction into furnaces
of alternate charges of crude material and material already roasted.
The application of this process of alternation to all kinds of furnaces,
that is to say :-
First. To furnaces with floors, properly so called, in which the
material is charged successively one floor with crude material, the next
with roasted, and so on, and in which the material is stagnent or rests
on the floors to the end of the operation.
Secondly. To furnaces, such as that herein-before described, that is
to say, formed by brickwork divided into chambers or compartments
charged the one with crude material and another with roasted material,
and arranged so as to effect by the communication of heat the further
roasting of material previously roasted, by charging the chambers or
compartments alternately with crude and roasted material.
Thirdly. To furnaces in which the material is thrown from one floor
on to another (per descensum), as represented in the Drawings, the
furnace so represented having the further advantage of supplying to the
material intended to be further roasted a considerably increased amount
of heat produced by pieces of crude ore that burn on the grate of the
furnace.
Fourthly. To furnaces in which the material is continually stirred.

page_text: The peculiar features intended to be indicated by the foregoing
description of the furnaces are as follows:-
-
The superposition or the combination of a furnace body and furnaces,
or heating chambers in floors, operating either on material resting on
the floors, or on material descending from one floor on to another, or on
crude material alternately with material already roasted, and finally, all
kinds of furnaces for further roasting.
The application of these processes of further roasting to other metal
pyrites besides iron, in order to convert them by the elimination of the
sulphur, cither whole or in small parts, into material suitable for being
submitted to treatment for the extraction of metal therefrom.
And I hereby declare that I claim as of the said Invention,-
First. The withdrawing from pyrites nearly the whole of the sulphur
in such a manner as to increase, without expense of fuel, the quantity
of gas to introduce into the chambers, and as a result the production of
sulphuric acid.
And, secondly. The conversion by this elimination of the sulphur of
ores containing pyrites into ore suitable for the extraction of metal
therefrom.
In witness whereof, I, the said William Spence, have hereunto
set my hand and scal, the Eleventh day of January, in the
year of our Lord One thousand eight hundred and seventy-two.
Witness,
W. A. JACKSON,
S, Quality Court,
Chancery Lane.
WILLIAM SPENCE. (L.S.)