IMPROVEMENTS IN THE CONSTRUCTION OF ROASTING FURNACES
Year: 1876

page_text: LETTERS PATENT to Joseph Theodore Dann, of 120, Stockwell Park Road, in the
County of Surrey, Civil Engineer, for the Invention of "IMPROVEMENTS IN THE
CONSTRUCTION OF ROASTING FURNACES." A communication from abroad by
William Brenton Symons and William Thompson Rickard, both of Maidanpek,
in the Principality of Servia.
Sealed the 6th April 1877, and dated the 22nd December 1876.
PROVISIONAL SPECIFICATION left by the said Joseph Theodore Dann at the
Office of the Commissioners of Patents on the 22nd December 1876.
"
JOSEPH THEODORE DANN, of 126, Stockwell Park Road, in the County of Surrey,
Civil Engineer. "IMPROVEMENTS IN THE CONSTRUCTION OF ROASTING FURNACES.'
A communication from abroad by William Brenton Symons and William Thompson
Rickard, both of Maidanpek, in the Principality of Servia.
This Invention has for its object to so improve the construction of roasting
furnaces, for the preparation of ores for the extraction of the metals contained
therein, as to utilise even the poorest ores, which in furnaces built upon the plans
usually followed would not repay any metallurgical treatment.
The first part of my Invention consists in a new method of feeding. I furnish
a three-hearth reverberatory furnace with a throat or gorge surmounted by a hopper
or other appropriate receptacle fitted with a screw or other suitable appliance for
regulating the delivery. Into the hopper I feed the ore, which may be pulverized by a
common Čornish or other crusher without any previous preparation, and conveyed by
tram-waggons, and shot into the hopper upon the usual plan. The pulverized ore I
scatter or disperse within the furnace by means of a fan blower, the conduits of
the blast being so arranged as to terminate in an aperture beneath the throat or
gorge through which the ore reaches the interior of the furnace. Owing to this
instananeous dispersion, the ore is oxidized almost as soon as it is brought in
contact with the blast.
The second part of my Invention consists in carrying air flues or pipes around the
lower hearth, so as to pass through the fire-bridge, and by the sides and end of
the furnace. By this inethod the blast intended to scatter the ore in the furnace is
constantly kept at an incandescent heat, and this result is achieved without in-
volving any additional expense.

page_text: The third part of my Invention consists in providing injectors of hot air descend-
ing from the pipes or flues afore-mentioned at the sides and the fire-bridge of
the furnace to the closed ash-pit of the fire-place. By the hot air proceeding from
these injectors, the oxidation of the coarser and more refractory portions of the ore,
the so-called roughs, is completed on the bottom hearth, whilst the more minute
and finer particles thereof are by the combined action of the blast, and of the draft
of the flame proceeding from the fire-place, blown to the upper hearths of the
reverberatory furnace, and thence to the dust chambers, within which the oxidation
of these particles is carried to its ultimate stage; it being however understood
that any method of feeding ores for oxidation with a blower may be applied to all
other descriptions of furnaces besides the reverberatory ones.
The last part of my Invention is designed to accelerate the condensation of the
acid vapours proceeding from the furnace. This object I achieve by the combination
of a steam jet with a coil of perforated water pipes, the former placed within, and
the latter at the upper part of a chimney or acid tower, at the bottom of which I
provide a vessel, made of lead or other suitable material, for the purpose of receiving
the condensed acids, and furnished with an overflow pipe for carrying the acids into
a cistern provided to that effect. By a combination of the various parts of iny
Invention, I reduce the cost of the construction of the furnace and of its working,
besides accelerating the operation in a considerable degree, and reducing the
number of hands required for the work to its minimum.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Joseph Theodore Dann in the Great Seal Patent Office on the 21st:
June 1877.
JOSEPH THEODORE DANN, of 126, Stockwell Park Road, in the County of
Surrey, Civil Engineer. "IMPROVEMENTS IN THE CONSTRUCTION OF ROASTING
FURNACES." A communication from abroad by William Brenton Symons and
William Thompson Rickard, both of Maidanpek, in the Principality of Servia.
This Invention has for its object to so improve the construction of roasting
furnaces for the preparation of ores for the extraction of metals contained therein,
as to utilize even the poorest ores, which in furnaces built upon the plans usually
followed would not repay any metallurgical treatinent.
The first part of my Invention consists in a new method of feeding. I furnish
a three-hearth reverberatory furnace with a throat or gorge surmounted by a
hopper or other appropriate receptacle fitted with a screw or other suitable appliance
for regulating the delivery. Into the hopper I feed the ore, which may be pulverized
by a common Cornish or other crusher without any previous preparation, and
conveyed by tram-waggons, and shot into the hopper upon the usual plan. The
pulverized ore I scatter or disperse within the furnace by means of a fan blower;
the conduits of the blast being so arranged as to terminate in an aperture beneath
the throat or gorge through which the ore reaches the interior of the furnace.
Owing to this instantaneous dispersion the ore is oxidized almost as soon as it is
brought in contact with the blast.
The second part of my Invention consists in carrying air flues or pipes around
the lower hearth, so as to pass through the fire-bridge, and by the sides and end of
the furnace. By this method the blast intended to scatter the ore in the furnace is
constantly kept at an incandescent heat, and this result is achieved without involving
any additional expense.
The third part of my Invention consists in providing injectors of hot air descend-
ing from the pipes or flues afore-mentioned at the sides and the fire-bridge of the
furnace to the closed ash-pit of the fire-place. By the hot air proceeding from
these injectors the oxidation of the coarser and more refractory portions of the
ON
ore,

page_text: of the flame proceeding from the fire-place, blown to the upper hearths of the
reverberatory furnace, and thence to the dust chambers, within which the oxidation
of these particles is carried to its ultimate stage, it being however understood that
my method of feeding ores for oxidation with a blower may be applied to all other
descriptions of furnaces besides the reverberatory ones,
The last part of my Invention is designed to accelerate the condensation of the
acid vapours proceeding from the furnace. This object I achieve by the combination
of a steam jet with a coil of perforated water pipes, the former placed within, and
the latter at the upper part of a chimney or acid tower, at the bottom of which I
provide a vessel, made of lead or other suitable material, for the purpose of receiving
the condensed acids, and furnished with an overflow pipe for carrying the acids into
a cistern provided to that effect. By a combination of the various parts of my
Invention, I reduce the cost of the construction of the furnace and of its working,
besides accelerating the operation in a considerable degree, and reducing the
number of hands required for the work to its minimum.
DESCRPTION OF DRAWINGS.
In the accompanying Sheet of Drawings Figure 1 is a longitudinal section of a
furnace constructed according to my Invention; Figure 2 is a sectional plan, and
Figure 3 a cross section thereof.
A, A, are the fire-places; B, B, the reverberatory hearths. Upon the tramway K tho
ores pass from the Cornish or other crusher in which they have been pulverized, and
which being of the well known usual construction I have not shown in the Draw-
ing, through the hopper J into the gorge Y, and thence through the orifice I into
the furnace. C, C, are the apertures for passing the ores into the lower hearths,
furnished with covers and raking doors N, N. The fan blower D, shewn only in
the elevation Figure 1, communicates by means of a tube d with the air pipes or
flues, E, E, passing all around reverberatory furnaces, that is to say, through the
fire-bridge, as well as by the sides and end thereof, in such a way as to secure the
complete scattering of the pulverized ores over the furnace, and constantly preserve
the blast coming from D at an incandescent heat. From these pipes or flues E, E, the
hot-air flues or injectors F, F, descend to the closed ash pit V of the fire-place A,
and the hot air, proceeding through these, completely oxidizes the roughs on the
bottom hearth B. While this is being enacted in the lower region, the more
minute particles of the ore are blown by the combined action of the blast and the
draft to the upper and reverberatory hearths, and thence into the dust chambers
L, L, in which the oxidation of these particles is completed. In furnaces not con-
structed upon the reverberatory plan the same method of combining the blast and
the draft in accordance with my Invention may be applied with identical efficacy.
O is the chimney or acid tower, with the coil of perforated water pipes P for the
condensation of acid vapors at the top thereof, and the steam jet Q within the said
chimney. R is the vessel at the bottom of the chimney or acid tower, designed to
receive the condensed acids, whilst the overflow pipe S carries the acids thus con-
densed into the cistern T, made of lead or other suitable material; M, M, are the
discharge doors on the sides of the dust chambers L, L; U is the tramway leading
to the lexiviating tanks, in which the ore is subjected to subsequent chemical
treatment; W, W, are the throats, and X, X, the doors of the fire-places, and Z, Z,
are the dampers for excluding the hot air when not required.
Having now described the nature of my said Invention, and illustrated the same
in the accompanying Sheet of Drawings, I wish it to be understood that I do not
claim the use of reverberatory furnaces for roasting metals, neither do I claim the
use of towers or shafts for feeding such furnaces, constructions of this kind having
been known and used heretofore, but what I claim is,-
First. The use or employment of a throat or gorge, with an orifice immediately
above the aperture of a hot air blast, for foeding pulverized ores into an ordinary

page_text: roasting furnace, in the manner herein set forth, and illustrated in the accompanying
Sheet of Drawings.
Secondly. The use or employment of air flues or pipes for keeping the blast at an
incandescent heat, as herein set forth and illustrated in the annexed Sheet of
Drawings.
Thirdly. The use or employment of injectors of hot air for completing the oxida-
tion of the roughs, as herein-before described and illustrated in the accompanying
Sheet of Drawings.
Fourthly. The use or employment of a steam jet in combination with a coil of
perforated water pipes for accelerating the condensation of the acid vapours proceed-
ing from the furnace, as herein-before set forth and illustrated in the accompanying
Sheet of Drawings.
In witness whereof, I, the said Joseph Theodore Dann, have hereunto set my
hand and seal, this Twenty-first day of June, in the year of our Lord One
thousand eight hundred and seventy-seven.
(L.S.) JOSEPH THEODORE DANN.
(L.S.) JOSEPH THEODORE DANN.