Improvements in Furnaces for Treating Ores.
Year: 1891

page_text: Date of Application, 14th Sept., 1891
Complete Specification Left. 14th July, 1892-Accepted, 20th Aug., 1892
PROVISIONAL SPECIFICATION.
Improvements in Furnaces for Treating Ores.
I, ELIZABETH BARNSTON PARNELL of The Acacias, Sutton in the County of
Surrey, Metallurgist, do hereby declare the nature of this invention to be as
follows:-
This invention relates to the furnaces employed in the calcining or treatment of
various kinds of ores, the furnaces being used as muffle or reverberatory furnaces,
as required. Preferably three or more of these furnaces are arranged one above
the other, the precise number and arrangement being a matter of adaptation to each
individual case.
Each furnace is made with an inner and an outer shell preferably concentric so as
to leave an approximately annular space between them, the tubes being not quite
circular in cross section the longer axis lying in the vertical plane; a shaft passes
longitudinally through the inner tube carrying a suitable screw for stirring the ore
and causing it to travel longitudinally through the furnace. The feed is preferably
by means of a hopper and shoot with worm feed, the discharge being similarly
arranged. The firing may be at one end of the furnace, suitable dampers or
equivalent being arranged to control the heat and the fire may be allowed to pass
through the space between the two shells and be carried off by a damper-controlled
flue provided for the purpose in the outer tube, or may pass directly through the
furnace and be carried off by a flue provided in the inner tube.
By making the vertical axes of the tubes longer than the horizontal one space is
provided above the top of the screw for the free escape of the fumes given off and
also for the smoke and products of combustion from the fire where these pass through
the interior tube. The heating may be by means of direct firing with coke, wood
or the like or by gas or by heated air or by the electric current as by a series of
ares disposed throughout the apparatus.
Where a series of furnaces is employed they may with advantage be arranged
one above the other the ore being fed to the topmost one and passed on auto-
matically by the worm conveyors from one furnace to the next until the ore
having been effectually calcined is discharged from the last furnace of the series.
The ore travels at a very slow speed so that it may be properly subjected to the
action of the heat. A common chimney or smoke stack may be provided for all the
furnaces of the set and also suitable flues for conveying the fumes from the interior
to the condenser, suitable dampers being employed wherever necessary for con-
trolling the draught. Each of the furnaces is provided with a suitable number and
arrangement of pipes or equivalent preferably with nozzles for conveying steam to
the ore; these pipes may be carried along the roof or upper part of the furnace.
The fire-boxes where such are employed would be built at one end of each of the
furnaces and preferably arranged one above another and each fitted with suitable
dampers and bridges for the control of the fire.
Suitable doors or covers are provided where required for access to the interior
and the furnaces may be built of any suitable material preferably of cast iron for
the inner shell and cast iron or fire-brick for the outer. A suitable protective
covering should be provided upon those portions which are exposed to the action of
the fire or heat and the exterior should be coated with some nonconducting material
to prevent the radiation of heat. The screw conveyors may be driven by steam
manual or other suitable power.
Dated this 14th day of September 1891.

page_text: COMPLETE SPECIFICATION.
Improvements-in Furnaces for Treating Ores..
J, ELIZABETH BARNSTON PARNELL of The Acacias, Sutton in the County of
Surrey, Metallurgist, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement:-
This invention relates to the furnaces employed in the calcining or treatment of
various kinds of ores, the furnaces being used as muffle or reverberatory furnaces,
as required. Preferably three or more of these furnaces are arranged one above
the other, the precise number and arrangement being a matter of adaptation to each
individual case.
Each furnace is made with an inner and an outer shell preferably concentric so
as to leave an approximately annular space between them, the tubes being not quite
circular in cross section the longer axis lying in the vertical plane; a shaft passes
longitudinally through the inner tube carrying a suitable screw for stirring the ore
and causing it to travel longitudinally through the furnace. The feed is preferably
by means of a hopper and shoot with worm feed, the discharge being similarly
arranged. The firing may be at one end of the furnace, suitable dampers or
equivalent. being arranged to control the heat and the fire may be allowed to pass
through the space between the two shells and be carried off by a damper-controlled
flue provided for the purpose in the outer tube, or may pass directly through the
furnace and be carried off by a flue provided in the inner tube.
By making the vertical axes of the tubes longer than the horizontal one space is
provided above the top of the screw for the free escape of the fumes given off and
also for the smoke and products of combustion from the fire where these pass through
the interior tube. The heating may be by means of direct firing with coke, wood
or the like or by gas or by heated air or by the electric current as by a series of
arcs disposed throughout the apparatus.
Where a series of furnaces is employed they may with advantage be arranged
one above the other the ore being fed to the topmost one and passed on automatically
by the worm conveyors from one furnace to the next until the ore having been
effectually calcined is discharged from the last furnace of the series.
The ore travels at a very slow speed so that it may be properly subjected to the
action of the heat. A common chimney or smoke stack may be provided for all
the furnaces of the set and also suitable flues for conveying the fumes from the
interior to the condenser, suitable dampers being employed wherever necessary for
controlling the draught. Each of the furnaces is provided with a suitable number 3
and arrangement of pipes or equivalent preferably with nozzles for conveying steam
to the ore; these pipes may be carried along the roof or upper part of the furnace.
The fire-boxes where such are employed would be built at one end of each of the
furnaces and preferably arranged one above another and each fitted with suitable
dampers and bridges for the control of the fire.
Suitable doors or covers are provided where required for access to the interior
and the furnaces may be built of any suitable material preferably of cast iron for the
inner shell and cast iron or fire-brick for the outer. A suitable protective covering
should be provided upon those portions which are exposed to the action of the fire
or heat and the exterior should be coated with some non-conducting material to 4
prevent the radiation of heat. The screw conveyors may be driven by steam manual
of other suitable power.
The invention will be best understood by reference to the accompanying drawings
of which
Fig. 1 is a longitudinal and Fig. 2 a cross section of my calcining furnace and a
which may be either of the muffle or reverberatory order.
Each furnace is provided with an outer and an inner shell H and I preferably

page_text: concentric so as to leave an approximately annular space between them; the tubes.
being not quite circular in cross section the longer axes lying in the vertical plane.
A shaft J jounalled in bearings J₁ passes longitudinally through the inner tube I
carrying a suitable screw or worm K for stirring the ore and causing it to travel
longitudinally through the furnace. The feed is preferably effected by means of a
hopper L and shoot with worm L' and pulley L', the discharge L' having also a
worm. The firing takes place in the fire-box m which may be fed by the hopper m¹
closed by the damper m³, suitable dampers M or equivalent being arranged to
control the heat, and the fire when it is desired to use the furnace as a muffle may
be allowed to pass through the space between the two concentric tubes H and I
and be carried off by the damper-controlled flue N provided for the purpose in the
outer tube. When on the other hand it is to be used as a reverberatory furnace
the fire passes through a door or opening I' in the tube I and directly through the
furnace, being carried off by a flue N₁ provided in the inner tube. By making the
vertical axes of the tubes longer than the horizontal ones space is provided above
the top of the screw K for the free escape of the fumes given off and also for the
smoke and products of combustion from the fire when these pass through the
interior tube.
Any required number of openings k may be provided in the screw K to facilitate
both the passage of gases and the cleaning of the blades. The inner tube I is
provided with one or more pipes O having nozzles 0' for conveying steam to the
ore; these pipes may be carried along the roof or upper part of the furnace and
are preferably air jacketted to prevent the steam from becoming dry. The ore
travels along at a very slow speed so that it may be thoroughly subjected to the
action of the heat and the screw conveyors may be driven by steam manual or other
suitable power.
The insoluble sulphides contained in the pyrites will in passing through the
roasting apparatus have become converted into soluble sulphates.
Having now particularly described and ascertained the nature of the said inven--
tion and in what manner the same is to be performed, I declare that what I
claim is,
1. In a furnace for the calcining of ores the employment of outer and inner
concentric tubes such as H and I which are not quite circular in cross section the.
longer axes lying in the vertical plane substantially as and for the purpose described
and illustrated in the accompanying drawings.
2. The combination in a furnace for the calcining of ores with two concentric.
shells such as H and I of the shaft J carrying a worm or screw K provided with
openings & one or more steam pipes O and nozzles O' the whole constructed and
operating substantially as described and illustrated in the accompanying drawings.
3. The combination and arrangement of parts constituting the complete calcining
furnace substantially as specified.
Dated this 19th day of July 1892.
E. B. PARNELL.
W. P. Thompson & Boult,
Agents for the Applicant..