Improvements in Ore Roasting Furnaces.
Year: 1892

page_text: Date of Application, 22nd Mar., 1892
Complete Specification Left, 26th Apr., 1892-Accepted, 2nd July, 1892
PROVISIONAL SPECIFICATION.
[Communicated from abroad by HORACE FOWLER BROWN, of 515, East Mercury
Street, in the City of Butte, County of Silver Bow, and State of Montana,
United States of America, Mechanical and Mining Engineer.]
Improvements in Ore Roasting Furnaces.
I, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co. Patent Agents,
45 Southampton Buildings in the County of Middlesex, do hereby declare the
nature of this invention to be as follows:-
My invention relates to that class of horizontal furnaces having two separate
longitudinal compartments forming hearths, one above the other, with connecting
passages between them, and employing carriages drawn by chains or cables, for
gradually conveying the ore from the feeding to the discharge opening; and my
invention consists of the constructions and combinations of devices which I shall
hereinafter fully describe.
To enable others skilled in the art to which my invention appertains to make
and use the same I will now describe its construction and indicate the manner in
which the same is carried out.
The furnace herein described is constructed of the usual materials, and is made
with two separate hearths one above the other, the upper hearth being designed for
the desulphurization of the ore, and the lower one for the chloridization, both
processes being performed at one operation.
The lower hearth connected with the upper one by means of a suitable opening,
whereby the ore is deposited from the upper compartment to the lower, and is
finally conveyed to the cooling floor as will be hereinafter described. Each hearth
has one or more fire-boxes communicating with it, and the furnace is provided with
a flue which leads to the main stack in the usual manner.
At each end of the furnace are mounted in any suitable manner, certain pulleys
or drums around which pass the chains or analogous devices, to which wheeled
carriers are attached and provided with means for stirring and advancing the ore
as hereinafter described and to a band wheel on the shaft of one set of these
pulleys or drums, power is applied from any suitable source to operate the chains,
said chains passing completely through the furnace, going in one way through the
upper compartment, and the other way through the lower compartment.
A serious objection to many furnaces of the type herein shown, is that the chains
and their attachments are drawn through the centre of the furnace and are thereby
exposed to the destroying action of the heat, dust and fumes from the ore, and
consequently these parts are soon destroyed.
A second objection arises from the fact that the plows or stirrers travel against
the floor of the compartments, which being usually made of brick, will not only
soon be cut in channels and worn out, but the plows or stirrers themselves will also
be quickly worn away.
The essential part of my invention lies in constructing the furnace so that these
objectionable features are avoided, and the moving or carrying parts protected
from the direct action of the heat, fumes and dust.
These objects are attained by the following construction.
Near the sides of each compartment, and extending the full length thereof are
laid track rails for certain wheeled carriers to which the endless chains are con-
nected in such manner that the carriers practically become links in the chains and
in order that these carriers may be removed from the direct action of the heat,
fumes and dust, I construct a vertical diaphragm wall or partition, between these
parts and the hearth, so that the carriers move in a housing where they are protected

page_text: from the injurious effects as above mentioned, whereby the usefulness of these parts
is greatly prolonged.
This diaphragm, wall, or partition consists preferably of two vertically disposed
parts, one of which is secured to the hearth, while the other depends from the roof,
and the adjacent ends of these parts are separated from each other by a space
through which arms from the wheeled carriers project and have fitted to them the
devices for advancing and stirring the ore.
These partition walls or diaphragms divide the upper and lower compartments
into three chambers, the middle one being the hearth proper, and the end ones
being for the mechanisms by which the material is operated, but in the case of a
very narrow furnace, one of the partitious or diaphragms may be dispensed with,
in which case but two chambers for each main compartment are necessary.
As before stated the wheeled carriers, are designed to run upon the track rails
in the supplemental compartments, and these carriers each consist of a suitable
frame having end bosses or bearings in which the shafts which carry the wheels.
are mounted, the ends of the frame being suitably connected with the chain whereby
they assist in supporting the weight of the chains while a scries of wheels placed
between the rails at suitable points assist in supporting the chains and prevent them
dragging.
From one side of each frame extends an arm which projects through the slot or
opening in the diaphragm or partition, and has fitted to it a sleeve or casing to
which diagonally disposed stirrers or blades are secured the casing or frame having
a plate or shield bolted to its inner side parallel with the frame, and located just
inside of the hearth, to cut off the direct heat, fumes and dust, and thereby close
the contiguous portion of the slot or opening in the partition or diaphragm to
protect and shield the carrier and its adjuncts and prevent the ore being crowded
into the slot or opening.
For ores that will oxidize at a low heat the stirrers are secured directly to the
inwardly projecting arm, but when working ores requiring a more intense and con-
tinued heat I prefer to secure these stirrers to a sleeve or casing which is adapted
to slip over the arm so as to completely encase the latter, and to this casing or
sleeve the stirrers are secured. The opening in the sleeve or casing is somewhat
greater than the diameter of the arm, and it is preferably lined with asbestos or
other non-conducting material to prevent the arm becoming highly heated or
affected by the fumes arising from the ores, and also to strengthen and make it
- more durable.
The stirrers or blades may also be coated or covered with a non-conducting
refractory substance, preferably asbestos cement prepared for use in chemical
works after which the stirrers or blades are subjected to a strong heat to vitrify
the cement, and form a solid durable coating on the stirrers and casing or sleeve
which is thus made impervious to ordinary heat, and the action of fumes and acids
arising from the burning ore.
The stirrers are designed to agitate and advance the ore along the hearth, and
to cause it to discharge through the openings made for its reception, as is common
in this class of furnaces.
In addition to the features above mentioned I have also modified the constructions
of the furnace in the manner in which the heat is admitted, because when the fire
is led directly to the furnace hearth, it impinges on the-ore at one side, and results
in fusing and "caking" the ore to the great detriment of the work.
My improvement in this connection consists, in carrying the arches over the
supplemental compartments in which the wheeled carriers run, and thereby admitting
,all the heat through central portion of the roof or arch so that it may impinge
directly and evenly upon the top of the material.
By this means the heat is distributed evenly and there can be no "caking" or
fusing of the ore, while at the same time the carriers and their operative mechanisms
are fully protected against the injurious action of the fire.
In the sides of the furnace openings or doors are made for the admission of air

page_text: to the two supplemental compartments which contain the wheeled carriers and their
adjuncts the said air finding its way through the slotted partitions or diaphragms
to the upper and lower hearths, in thin sheets, which is distributed directly upon the
surface of the ore the entire length of the furnace.
This stream of air being cooler than the heated gases with which the furnace
is charged will diffuse itself evenly over the ore before becoming rarified by
the heat, and will thus furnish a greater amount of available oxygen than can be
obtained in the usual manner and which greatly increases the efficiency of the
furnace.
In treating lead ores, flue dust and other products that require partial fusing or
slagging, I employ also an auxiliary slagging hearth. This auxiliary hearth is
located under the roasting hearth at the discharge end of the furnace, and the
calcined ore is discharged through the flue or opening by the stirrers. By means
of the fire box an intense heat can be thrown upon the ore as it is on the slagging
hearth, and this ore being already red hot it is rapidly fused to any desired extent,
with no additional cost except raking it out in the form of slag, as the heat from
the fire box passing into the main hearth through the flue or opening is utilized in
desulphurizing the ores:
In constructing new furnaces, the partition, wall or diaphragm can be made of
brick or tiling, but in remodeling old furnaces, this diaphragm may be made of
metal plates coated with clay or asbestos.
At the ends of the furnace the partitions or diaphragms are extended beyond the
walls, and between these ends suitable revolving doors are mounted so that they
may close the ends of the hearths, as tightly as possible against the ingress of
outside air. These doors each consist of end wings or plates located at the ends of
a hub or cylinder mounted on a shaft passing transversely through the extended
ends of the diaphragm and suitably journaled. These plates or wings are formed
with openings in the central portions of their outer edges, and these openings are
adapted to receive the arms of the wheeled carriers, whereby the passage of the
latter causes a partial revolution of the doors.
From the central hub or cylinder radiate the arms which form the doors proper,
and certain curved plates serving to prevent admission of air during the movement
of the doors.
As the wheeled carriers pass out of the ends of the furnace, their projecting
arms strike the doors and cause the latter to turn about their journals, and as the
nearest arm is moved away by the passage of the carrier, the arm next above it is
caused to close down behind the carrier and thereby close the end of the furnace
so as to shut out the air, and leave this second arm in a position where the
succeeding carrier may strike it and operate the door as before described. By
reason of this construction the doors are operated automatically by the passage of
the wheeled carriers and the influx of air to the furnace is reduced to a minimum:
The supplemental chambers are also provided with doors and these doors are
preferably pivotally hung from the hub or cylinder shaft aforementioned shaft
which carries the main furnace doors so that they too may be lifted by the passing
vehicle and close by gravity behind them to shut out the air from the supplemental
chambers.
In roasting and chloridizing ores an abundant supply of free oxygen is a necessity,
and to insure such a supply of oxygen without causing a cooling of the surface of
the ore, is an important factor in this class of furnaces, and to attain these results
I form certain air spaces or passages above and around the fire boxes and in the
arches through which air may be discharged into the heating chambers or hearths
in a heated condition.
In the auxiliary slagging chamber the air passing around the fire box, becomes
heated and is discharged through holes in the bridge wall and thereby acts to
consume the smoke by furnishing free oxygen to burn all unconsumed carton.
This greatly intensifies the heat at this point and causes a more complete combus-
tion of the fuel used. By means of the air duct or passage in the arch between the

page_text: :
hearths, air is heated and may be discharged through the ducts or passages in the
partitions or diaphragms on to the body of ore on the hearths.
The discharge in this case will be from the side, while the discharge in some
cases may take place through openings in the arches.
I prefer to discharge the heated air into the supplemental chambers, in all cases
where a low heat can be used, but where a great heat is required, the air is
preferably discharged into the main chambers through the roof to avoid heating
the wheeled carriers and adjunctive parts. The amount of air passing through the
passage or duct in the arches is regulated by suitable doors.
Where brick or tiling is used to form the lower portion of the diaphragm or
partition the heated air is brought up through the passages formed in them. In
building new furnaces this would be the preferable way but in remodeling old
furnaces owing to the lack of space the heated air may be introduced into the main
chambers.
In the art of sintering ores it is a recognized practice to fuse the ores by the
application of heat until they begin to become pasty and the fine particles adhere.
This condition is produced by spreading a previously roasted charge over the
sintering hearths and exposing it to a gradually increasing heat until the surface
begins to melt. This charge is then worked towards the point of greatest heat and
gradually worked up and agitated, and exposed to the action of the heat until it
has gathered into balls or spongy cakes whose particles adhere.
This operation is continued until there is no ore left in a fine state of division,
when the charge is drawn out and a new charge spread upon the sintering hearth.
The roasted ore or calcine is discharged from the roasting hearth in a practically
continuous manner and in a fine state of sub-division and is dragged to the hoppers
or to an opening which communicates with the sintering hearth upon which it
accumulates the requisite amount of material necessary to form a new charge while
the previous charge is being sintered.
Referring now particularly to an ore roasting furnace having independent main
hearths located one above the other and having a communication or opening
between them, said upper hearth being designed for the desulphurisation of the ore
preparatory to fusing or sintering.
At each end of the furnace, drums or pulleys are mounted and around these
drums pass the endless chains or analogous devices to which wheeled carriers are
attached and provided with means for stirring and advancing the ore as before
described.
At the ends of the furnace the revolving doors are placed to close the entrance
to the roasting compartments, but to turn about their axis when engaged by the
travelling carriers, whereby the doors are automatic in their movement.
Along each side of the main compartments or hearths are formed supplemental
or side compartments, separated from the main compartments by partitions or walls
having longitudinal slots through which the arms of the stirrers pass.
At one end, the furnace is extended to form a sintering hearth, which lies in a
plane somewhat below the plane of the lower main roasting hearth, and to allow
the accumulation of the roasted ore, without danger of the latter becoming
prematurely fused, this sintering hearth is constructed with side flues along the
inside of its inner end, which communicates with openings or flues leading directly
to the main roasting hearths.
By means of these flues the heat is drawn away from the accumulating charge of
roasted ores and passes through the side flues into the main roasting hearths where
it is utilized for burning sulphurs from the ores.
Also by the means described, the excess of heat required to sinter and fuse ores
is delivered to the main roasting hearths and diffused without danger of its over
heating or fusing the ore before the latter has arrived at the proper point. To
make this feature clear I would state that, should the heat from the sintering
hearth be carried up through the opening through which the ore is passed to the
sintering hearth, the accumulating charge would so far fuse as to become an

page_text: become fused at the point of discharge.
At the sides of the main roasting hearths are formed vertical flues joined at their
upper ends by a transverse flue passing over the upper hearth and receiving the
dust and heat therefrom, said flues having their lower ends connecting with the
dust flue, in the lower part of the furnace, and said dust flues communicating at its
inner end with the flue leading to the main stack.
To avoid overheating of the ore, and stirring mechanism while the stirrers are at
rest or not in action, an opening is made from each of the side flues to the vertical
flues and is controlled by a damper, whereby when these latter are open the heat.
from the sintering hearth passes directly to the main stack.
The fuse box is of any suitable construction having a fire box at one end and.
having its rear end contracted and connecting with a transverse passage leading to
side flues which in turn lead to the lower roasting hearth.
From the transverse passage or flue another flue extends centrally along the lower
portion of the furnace, and connects with another side flue also communicating with
the roasting bearth.
At the inner end of the central flue is a safety door operated by à lever whereby
when the door is open the entire heat from the fuse box passes into the dust flue and
from thence escapes through the stack.
It will thus be seen that, in fusing, the operation is similar to that carried on
sintering, only a more intense heat is necessary, and in order that all the ore may be
brought under the proper degree of heat, a somewhat modified construction is
necessary; therefore, instead of dividing the heat as in sintering, the fuse box is
made narrower at its rear end than at its front, and the heat is taken under the
main roasting hearths in the centre and is there divided and taken up and into the
roasting hearths by the side flues or passages before mentioned.
As the heat in fusing ore is necessarily excessive, it is often advisable and
necessary to divide it, therefore the importance of my central flue and the system
of dampers will be obvious as a desired proportion of the excessive heat can be
carried and delivered to the main roasting hearths in such a manner as to cause its
diffusion without injury to the ore.
The roasted ore is discharged by the stirrers from the main roasting hearths into
suitable hoppers whose spouts lead through the top wall of the fuse box and are
provided with gates or valves whereby the feed of roasted ore to the fuse box is
regulated at pleasure, and when the fusing of the ore has been accomplished the
melted ore is drawn from the fuse box through the side doors and a fresh charge is
delivered from the hoppers.
In the main roasting chambers openings are made to receive certain metal boxes:
which are located directly under the arches or roofs of said chambers and provided
with a foraminated floor or bottom extending entirely across the width of the
roasting hearths. These boxes connect with any suitable source of gas, supply
whereby the jets of flame from the foraminated floors of the boxes play on and
along the ore as may be desired. This construction insures a uniform heat clear
across the hearths and gives much better results in roasting ores than the means
usually employed.
The means employed for stirring and advancing the ore along the main roasting
hearths, differ in construction from those before set forth, and consist essentially in
forming the frame of the wheeled carriers with metal hubs or sockets which project
through the slotted portions of the partitions or division walls forming the side
compartments, said hubs or sockets being elongated in form and bored at each end
to receive the outwardly extending arms or rods separated from each other and
arranged parallel one with the other. Upon these rods the stirrer blades are secured,
and each blade is formed with oppositely extending wings formed by cutting the
sides of the blade at two points equi-distant from its centre, and bending the cut
portions in opposite lines to form the wings which lie in parallel planes. In these
wings holes are made to enable the blades to be slipped over and along the arms or

page_text: rods the bent portions or wings standing at right angles to the rods and the body
of the blades being inclined thereto. Fitted upon the arms or rods between the
blades are sleeves or thimbles having their ends cut square and at right angles to
their axis, adapted to hold the blades apart and also to serve as a protection for the
arms or rods aforesaid.
The arms or rods are therefore provided with alternate stirrers and spreaders,
and they are fitted to the hubs or sockets and secured in position and tightened by
means of nuts.
The spreaders being square on their ends, add materially to the strength and
rigidity of the arms when tightened together, by means of the nuts and there being
two arms or rods for each carriage the blades or stirrers cannot rock on their
bearings or become misplaced, and each blade forms an effective brace uniting each
arm or rod with the other, thereby making the stirring devices doubly strong.
Dated this 22nd day of March 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Ore Roasting Furnaces.
I, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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
My invention relates to that class of horizontal furnaces having two separate
longitudinal compartments forming hearths, one above the other, with connecting
passages between them, and employing carriages drawn by chains or cables, for
gradually conveying the ore from the feeding to the discharge opening.
My said invention consists of the constructions and combinations of devices
hereinafter described.
The accompanying drawings show how my said invention may be conveniently
and advantageously carried into practice.
Figure 1, is a side elevation of an ore roasting furnace embodying my
invention.
Figure 2 is a horizontal sectional view of the same on the line 2-2 of
Figure showing a portion of the upper hearth broken away to disclose the
lower hearth.
Figure 3 is a central longitudinal sectional view through one end of the
furnace.
Figure 4 is a cross sectional view on the line 3-3 of Figure 2.
Figure 5 is a longitudinal sectional view through one end of the furnace and
showing the auxiliary hearth for slagging lead ore and the like.
Figure 6 is a cross sectional view on the line 4-4 of Figure 2.
Figure 7 is a plan partially in section, of one of the carriers with its stirrers and
adjunctive parts.
Figure 8, is a side elevation of Figure 7.
Figure 9 is a detail showing one of the stirrers and the shield for protecting the
wheeled carriages.
Figure 10 is an enlarged detail of one of the revolving doors showing a portion
of one end of the furnace.
Figure 11 is a front view of the same partially in section.
Figure 12, is an elevation partly in section of a portion of the furnace showing
the hot air passages.
Figure 13, is a cross sectional view of the same on the line 5-5 of Figure 12.

page_text: Figure 15, is a horizontal sectional view of the same on the line 6-6 of
Figure 14.
Figure 16 is a transverse sectional view on the line 7-7 of Figure 15.
Figure 17, is a similar view on the line S-S of Figure 15.
Figure. 18, is a similar view on the line 9-9 of Figure 15.
Figure 19, is a similar view on the line 10-10 of Figure 14.
Figure 20, is an enlarged vertical longitudinal section of one end of the furnace
showing a fuse box and means for delivering the material from the main roasting
hearths to the fuse box.
Figure 21, is a horizontal sectional view of the same on the line II-11 of
Figure 20.
Figure 22, is a side elevation of one of the wheeled carriers which carry the
stirrer arms and blades.
Figure 23, is a plan view of the same.
Figure 24, is a cross sectional view on the line 12-12 of Figure 23.
Figures 25 and 26, illustrate detail views of the stirrer blades.
The furnace herein described is constructed of the usual materials, and is made
with two separate hearths and one above the other, the upper hearth being designed
for the desulphurization of the ore, and the lower one for the chloridization, both
processes being performed in one operation.
The lower hearth is connected with the upper one by means of an opening C
whereby the ore is deposited from the upper compartment to the lower, and is
finally conveyed to the cooling floor as will be hereinafter described. Each
hearth has one or more fire-boxes W communicating with it, and the furnace
is provided. with a flue Figure 2 which leads to the main stack in the usual
manner.
At each end of the furnace are mounted in any suitable manner, pulleys or
drums D around which pass the chains E or analogs devices, to which wheeled
carriers are attached and provided with means for stirring and advancing the ore
as hereinafter described.
Power is applied to a band wheel D' on the shaft of one set of these pulleys or
drums, from any suitable source to operate the chains, said chains passing completely
through the furnace, in one direction through the upper compartment, and the
opposite direction through the lower compartment.
A serious objection to many furnaces of the type herein shown, is that the chains
and their attachments are drawn through the centre of the furnace and are thereby
exposed to the destroying action of the heat, dust and fumes from the ore, and
consequently these parts are soon destroyed.
A second objection arises from the fact that the ploughs or stirrers travel against
the floor of the compartments, which being usually made of brick, will not only
soon be cut in channels and worn out, but the ploughs or stirrers themselves will
also be quickly worn away.
The essential part of my invention lies in constructing the furnace so that these
objectionable features are avoided, and the moving or carrying parts protected
from the direct action of the heat, fumes and dust.
These objects are attained as follows:-Near the sides of each compartment, and
extending the full length thereof are laid track rails a for the wheeled carriers F
as shown, to which the endless chains are connected in such manner that the carriers
practically become links in the chains and in order that these carriers may be
removed from the direct action of the heat, fumes and dust I construct a vertical
diaphragmn wall or partition G, between these parts and the hearth so that the
carriers move in a housing where they are protected from the injurious effects
as above mentioned, whereby the usefulness of these parts is greatly prolonged.
.
This diaphragm, wall, or partition consists preferably of two vertically disposed
parts, one of which is secured to the hearth, while the other depends from the roof,

page_text: and the adjacent ends of these parts are separated from each other by a space b
through which arms c from the wheeled carriers project and have fitted to them
the devices for advancing and stirring the ore.
These partition walls or diaphragms G, divide the upper and lower compartments
into three chambers, the middle one being the hearth proper, and the end ones
being for the mechanisms by which the material is operated but in the case of a
very narrow furnace, one of the partitions or diaphragms may be dispensed with,
in which case but two chambers for each main compartment are necessary.
As before stated the wheeled carriers F are designed to run upon the track rails
in the supplemental compartments H, and these carriers each consist of a suitable
frame d having end bosses or bearings 2 in which the shafts e which carry the
wheels, are mounted, the ends of the frame being suitably connected with the
chain substantially as shown in Figure 7 whereby they assist in supporting
the weight of the chains while a series of wheels Figure 4 placed between the rails
at suitable points assist in supporting the chains and prevent them dragging.
From one side of each frame d extends an arm c which projects through the slot
or opening in the diaphragm or partition G, and has fitted to it a sleeve or casing g
to which diagonally disposed stirrers or blades h are secured the casing or frame
having a plate or shield bolted to its inner side parallel with the frame d, and
located just inside of the hearth, to cut off the direct heat, fumes and dust, and
thereby close the contiguous portion of the slot or opening in the partition or
diaphragm to protect and shield the carrier and its adjuncts and prevent the ore
being crowded into the slot or opening.
For ores that will oxidize at a low heat the stirrers are secured directly to the
: inwardly projecting arm but when working ores requiring a more intense and
continued heat I prefer to secure these stirrers to a sleeve or casing g which is
adapted to slip over the arm e so as to completely encase the latter, and to this
casing or sleeve the stirrers are secured. The opening in the sleeve or casing is
somewhat greater than the diameter of the arm, aud-it is preferably lined with
asbestos or other non-conducting material to prevent the arm becoming highly
treated, or affected by the fumes arising from the ores, and also to strengthen and
make it more durable.
The stirrers or blades may also be coated or covered with a non-conducting
refractory substance, preferably asbestos cement prepared for use in chemical
works after which the stirrers or blades are subjected to a strong heat to vitrify
the cement, and form a solid durable coating on the stirrers, and casing or sleeve,
which is thus made impervious to ordinary heat, and the action of fumes and acids
arising from the burning ore.
The stirrers are designed to agitate and advance the ore along the hearth, and
to cause it to discharge through the openings made for its reception, as is common
in this class of furnaces.
In addition to the features above mentioned I have also modified the constructions
of the furnace in the manner in which the heat is admitted, because, when the fire is
led directly to the furnace hearth, it impinges on the ore at one side, and results in
fusing and "caking" the ore to the great detriment of the work.
My improvement in this connection consists, in carrying the arches over the
supplemental compartments in which the wheeled carriers run, and thereby admitting
all the heat through central portion of the roof or arch so that it may impinge
directly and evenly upon the top of the material.
"
By this means the heat is distributed evenly and there can be no caking" or
fusing of the ore, while at the same time the carriers and their operative mechanisms
are fully protected against the injurious action of the fire.
In the sides of the furnace, openings or doors are made for the admission of air
to the two supplemental compartments which contain the wheeled carriers and their
adjuncts the said air finding its way through the slotted partitions or diaphragms
to the upper and lower hearths, in thin sheets, which is distributed directly upon
the surface of the ore the entire length of the furnace.

page_text: This stream of air being cooler than the heated gases with which the furnace is
charged, will diffuse itself evenly over the ore before becoming rarified by the
heat, and will thus furnish a greater amount of available oxygen than can be
obtained in the usual manner, and which greatly increases the efficiency of the
furnace.
In treating lead ores, flue dust and other products that require partial fusing or
slagging, I employ also an auxiliary slagging hearth M shown in Figure 5. This
auxiliary hearth is located under the roasting hearth at the discharge end of the
furnace, and the calcined ore is discharged through the flue or opening N by the
stirrers. By means of the fire box O, an intense heat can be thrown upon the ore
as it is on the slagging hearth, and this ore being already red hot, it is rapidly
fused to any desired extent with no additional cost except raking it out in the form
of slag, as the heat from the fire box passing into the main hearth through the flue
or opening N is utilized in desulphurizing the ores.
In constructing new furnaces, the partition, wall or diaphragmn.G can be made of
brick or tiling, but in remodelling old furnaces, this diaphragm may be made of
metal plates coated with clay or asbestos as shown in Figure 4.
At the ends of the furnace the partitions or diaphragms are extended beyond
the walls, and between these ends suitable revolving doors are mounted so that
they may close the ends of the hearths, as tightly as possible against the ingress
of outside air. These doors, see Figures 10 and 11, each consist of end wings or
plates 10 located at the ends of a hub or cylinder 11 mounted on a shaft 12 passing
transversely through the extended ends of the diaphragm G and suitably
journalled. These plates or wings 10 are formed with openings 13 in the central
portions of their outer edges, and these openings are adapted to receive the arms c
of the wheeled carriers whereby the passage of the latter causes a partial
revolution of the doors.
From the central hub or cylinder 11 radiate the arms 14 which form the doors
proper, curved plates 15 serving to prevent admission of air during the movement
of the doors.
As the wheeled carriers pass out of the ends of the furnace, their projecting
arms strike the doors and cause the latter to turn about their journals, and as the
nearest arm is moved away by the passage of the carrier, the arm next above it is
caused to close down behind the carrier, and thereby close the end of the furnace
so as to shut out the air, and leave this second arm in a position where the
succeeding carrier may strike it and operate the door as before described. By
reason of this construction the doors are operated automatically by the passage of
the wheeled carriers and the influx of air to the furnace is reduced to a
minimum.
The supplemental chambers are also provided with doors Z and these doors are
preferably pivotally hung from the shaft 12 so that they too may be lifted by the
passing vehicle and close by gravity behind them to shut out the air from the
supplemental chambers.
In roasting and chloridizing ores an abundant supply of free oxygen is a
necessity, and to insure such a supply of oxygen, without causing a cooling of the
surface of the ore, is an important factor in this class of furnaces, and to attain
these results form air spaces or passages 16 and 17 above and around the fire
boxes and in the arches (see Figures 12 and 13) through which air may be
discharged into the heating chambers or hearths in a heated condition.
In Figure 12, the auxiliary slagging chamber M, is shown in section and the air
passing around the fire box, becomes heated and is discharged through holes 18 in
the bridge wall 19 and thereby acts to consume the smoke by furnishing free
oxygen to burn all unconsumed carbon. This greatly intensifies the heat at this
point and causes a more complete combustion of the fuel used. By means of the
air duct or passage 17 in the arch between the hearths A and B, air is heated and
may be discharged through the ducts or passages 20 in the partitions or
diaphragms G (see Figure 13) onto the body of ore on the hearths.

page_text: The discharge in this case will be from the side, while in Figure 4, the discharge
is from above through openings in the arches.
I prefer to discharge the heated air into the supplemental chambers, in all cases
where a low heat can be used, but where a great heat is required, the air is
preferably discharged into the main chambers through the roof to avoid heating
the wheeled carriers and adjunctive parts. The amount of air passing through
the passage or duct in the arches is regulated by suitable doors 21.
Where brick or tiling is used to form the lower portion of the diaphragm or
partition G, see Figure 13, the heated air is brought up through the passages 20
formed in them as shown. In building new furnaces this would be the preferable
way, but in remodelling old furnaces, owing to the lack of space, the heated air
may be introduced into the main chambers as shown in Figure 4.
In the art of sintering ores it is a recognised practice to fuse the ores by the
application of heat until they begin to become pasty and the fine particles adhere.
This condition is produced by spreading a previously roasted charge over the
sintering hearths, and exposing it to a gradually increasing heat until the surface
begins to melt. This charge is then worked towards the point of greatest heat,
and gradually worked up and agitated, and exposed to the action of the heat until
it has gathered into balls or spongy cakes whose particles adhere.
This operation is continued until there is no ore left in a fine state of division,
when the charge is drawn out and a new charge spread upon the sintering hearth.
The roasted ore or calcine is discharged from the roasting hearth in a practically
continuous manner and in a fine state of sub-division and is dragged to the hoppers
or to an opening which communicates with the sintering hearth upon which it
accumulates the requisite amount of material necessary to form a new charge while
the previous charge is being sintered.
Referring now particularly to Figures 14 to 21 inclusive A¹ represents an pre
roasting furnace having independent main hearths B B located one above the
other and having a communication or opening C between them, said upper
hearth B being designed for the desulphurization of the ore preparatory to fusing
or sintering.
At each end of the furnace, drums or pulleys D are mounted and around these
drums pass the endless chains E or analogous devices to which wheeled carriers F
are attached and provided with means for stirring and advancing the ore as before
described.
At the ends of the furnace the revolving doors J are placed to close the
entrance to the roasting compartments but to turn about their axis when engaged
by the travelling carriers, whereby the doors are automatic in their movement.
Along each side of the main compartments or hearths B1 and B2 are formed
supplemental or side compartments H, separated from the main compartments by
partitions or walls G having longitudinal slots b through which the arms of the
stirrers pass.
At one end, the furnace is extended to form a sintering hearth K, which lies in a
plane somewhat below the plane of the lower main roasting hearth B2, and to allow
the accumulation of the roasted ore, without danger of the latter becoming
prematurely fused, this sintering hearth is constructed with side flues L along the
inside of its inner end, which communicates with openings or flues F leading
directly to the main roasting hearths.
.
By means of these flues the heat is drawn away from the accumulating charge of
roasted ores and passes through the side flues L into the main roasting hearths
where it is utilized for burning sulphurs from the ores.
Also by the means described, the excess of heat required to sinter and fuse ores
is delivered to the main roasting hearths and diffused without danger of its
overheating or fusing the ore. before the latter has arrived at the proper point.
To make this feature clear I would state that, should the heat from the sintering
hearth be carried up through the opening B³ through which the ore is passed to
the sintering hearth, the accumulating charge would so far fuse as to become an

page_text: manageable mass before it could be moved and the ore on the mam nearth would
become fused at the point of discharge.
At the sides of the main roasting hearths are formed vertical flues N¹ joined at
their upper ends by a transverse flue N passing over the upper hearth E' and
receiving the dust and heat therefrom, said flues N' having their lower ends
connecting with the dust flue O¹, in the lower parts of the furnace and said
dust flue communicating at its inner end with the flue P leading to the main
stack.
To avoid overheating of the ore, and stirring mechanism while the stirrers are
at rest or not in action, an opening Q is made from each of the side Hues L, to the
vertical flues N' and is controlled by a damper R, whereby when these latter are
open the heat from the sintering hearth passes directly to the main stack.
In Figures 20 and 21 are shown longitudinal and horizontal sections of the
furnace taken through the fuse box. The fuse box S is of any suitable
construction having a fire box T at one end and having its rear end contracted and
connecting with a transverse passage U leading to side flues V which in turn lead
to the lower roasting hearth B².
From the transverse passage or flue U another flue W extends centrally along
the lower portion of the furnace, and connects with another side flue Xalso
communicating with the roasting hearth B².
At the inner end of the central flue W' is a safety door Y operated by a lever Z¹
whereby when the door is open the entire heat from the fuse box passes into the
dust flue O and from thence escapes through the stack.
It will thus be seen that, in fusing, the operation is similar to that carried on
sintering, only a more intense heat is necessary, and in order that all the ore may
be brought under the proper degree of heat, a somewhat modified construction is
necessary; therefore, instead of dividing the heat as in sintering, the fuse box is
made narrower at its rear end than at its front, and the heat is taken under the
main roasting hearths in the centre and is there divided and taken up and into the
roasting hearths by the side flues or passages before mentioned.
As the heat in fusing ore is necessarily excessive, it is often advisable and
necessary to divide it, therefore the importance of my central flue W and the
system of dampers will be obvious as a desired proportion of the excessive heat
can be carried and delivered to the main roasting hearths in such a manner as to
cause its diffusion without injury to the orc.
The roasted ore is discharged by the stirrers from the main roasting hearths B
and B into suitable hoppers C2 whose spouts lead through the top wall of the fuse
box and are provided with gates or valves D' as shown in Figure 20 whereby the
feed of roasted ore to the fuse box is regulated at pleasure, and when the fusing of
the ore has been accomplished the melted ore is drawn from the fuse box through
the side doors E' and a fresh charge is delivered from the hoppers.
In the main roasting chambers B and B see Figures 14, 18 and 19 openings
are made to receive metal boxes which are located directly under the arches or
roofs of said chambers and provided with a foraminated floor or bottom
extending entirely across the width of the roasting hearths. These boxes F¹
connect with any suitable source of gas supply whereby the jets of flame from the
foraminated floors of the boxes play on and along the ore as may be desired. This
construction insures a uniform heat clear across the hearths and gives much better
results in roasting ores than the means usually employed.
The means employed for stirring and advancing the ore along the main roasting
hearths, differ in construction from those before set forth, and consist essentially
in forming the frame of the wheeled carriers F with metal hubs or sockets
which project through the slotted portions of the partitions or division walls G
forming the side compartments H, said hubs or sockets being elongated in form
and bored at each end to receive the outwardly extending arms or rods c', separated
from each other and arranged parallel as shown in Figure 23. Upon these rods
the stirrer blades d' are secured, and each blade is formed with oppositely

page_text: extending wings e formed by cutting the sides of the blade at two points equi-
distant from its centre, and bending the cut portions in opposite lines to form the
wings which lies in parallel planes. In these wings e holes f1 are made to
enable the blades to be slipped over and along the arms or rods c¹ the bent
portions or wings el standing at right angles to the rods and the body of the blades
being inclined thereto as shown. Fitted upon the arms or rods c' between the
blades are sleeves or thimbles g' having their ends cut square' and at right angles
to their axis, adapted to hold the blades apart and also to serve as a protection
for the arms or rods c¹.
The arms or rods c' are therefore provided with alternate stirrers and spreaders,
and they are fitted to the hubs or sockets and secured in position and tightened
by means of nuts h¹.
The spreaders being square on their ends, add materially to the strength and
rigidity of the arms when tightened together, by means of the nuts and there
being two arms or rods for each carriage the blades or stirrers cannot rock on their
bearings or become misplaced, and each blade forms an effective brace uniting each
arm or rod with the other, thereby making the stirring devices doubly strong.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1. In an ore roasting furnace having means for stirring and advancing the orc,
a supplemental chamber at the side of the main roasting chamber and cut off from
said main chamber by a wall or partition, and carriers in said supplemental chambers
connected with the stirrers but removed from the direct action of the heat, fumes
and dust substantially as herein described.
2. In an ore roasting furnace having separate hearths one above the other,
separate supplemental compartments at the sides of the hearths separated from the
latter by a slotted wall or partition, wheeled carriers in said supplemental
chambers connected with stirrers in the main chambers or hearths, chains con-
nected with the carriers, and means for operating the chains substantially as herein
described.
3. In an orc roasting furnace having upper and lower hearths movable vehicles
at the sides of the hearths having stirrers connected with them and extending
toward the centre of the hearths, chains connected with said vehicle and walls or
partitions separating the vehicles and chains from the main chambers or hearths,
whereby the former are not affected by the direct heat, fumes and dust from said
hearths, said walls or partition having slots or openings in them for the passage of
the stirrer support, substantially as herein described.
4. In an ore roasting furnace, a wheeled carrier adapted to travel within the
same having a laterally projecting arm to which stirrers or blades are attached,
and means for operating the carrier, substantially as herein described.
5. In an ore roasting furnace, having track rails within it, the wheeled carriers
adapted to travel upon said rails, arms projecting laterally from the frames of the
carriers toward the centre of the furnace, chains connected with the carriers, sleeves
or casings fitted to the arms and provided with stirrers or blades, and means for
operating the chains, substantially as herein described.
6. In an ore roasting furnace, slotted walls or partitions extending longitudinally
through the roasting hearth or chamber a short distance from the sides thereof to
form supplemental chambers cut off from the direct heat, fumes and dust of
the main chamber, in combination with wheeled, carriers in said supplemental
chambers having arms projecting through the slots or openings thereof into the
main chamber and provided with stirrers or blades, shields or plates on the carriers
for closing the portions of the slots or openings contiguons to them whereby
the carriers are protected; and means for moving the carriers, substantially as
herein described.
7. In an ore roasting furnace, the stirrer blades coated or covered with

page_text: asbestos cement to form a vitrified surface impervious to ordinary heat, and the
action of the fumes and acids arising from the ore, substantially as herein
described.
8. In an ore roasting furnace, the stirrer carriers having laterally projecting arms
and menus for operating the carriers, in combination with sleeves or casing fitted to
the arms and having an inner lining. of asbestos, and stirrers or blades on the sleeves
or casings, substantially as herein described.
9. In an ore roasting furnace having side chambers cut off by a slotted wall or
partition from the main chamber, the operating chains, the wheeled carriers in said
side chambers let into the length of the chains to support the latter, the stirrers or
blades supported from the carriers and extending through the slotted wall or
partition into the main chambers, and wheels or rollers on the floor of the supple-
mental chambers for assisting in supporting the chains, substantially as and for the
purpose described.
10. An ore roasting furnace having longitudinally extending slotted walls or
partitions along the sides of its main chambers to form supplemental chambers,
movable carriers in said side chambers provided with means for stirring the ore,
and openings in the sides of the furnace leading to the side chambers whereby air
is admitted in thin sheets to the main chambers through the side chambers and
slotted walls or partitions, substantially as and for the purpose described.
11. In an ore roasting furnace having upper and lower hearths for the desul-
phurization and chloridization of the ore and provided with longitudinally extending
walls or partitions forming supplemental side chambers, the roofs or arches of the
hearths, extending over and closing the tops of the side chambers and forming a
centrally disposed opening over the body of ore, fire boxes having flues leading to
said central openings, and carriers in the supplemental side chambers having stirrers
extending into the main chamber for agitating and advancing the ore, substantially
as herein described.
12. In an ore roasting furnace having a main chamber or hearth, a supplemental
slagging hearth under the main hearth, and a fire box contiguous thereto having a
flue or passage leading to the main hearth or chamber whereby the products of
combustion from the fire box pass over the slagging hearth and enter the main
hearth or chamber to assist in the roasting of the ore, substantially-as herein
described.
13. In an ore roasting furnace the combination of the roasting chambers, and
connecting passages, the slotted partitions in said chambers forming supplemental
side chambers and extending beyond the ends of the furnace to form housings,
shafts journalled in the housings, doors pivotally mounted on said shaft at the ends
of the main and supplemental chambers and carriers in the side chambers
supporting stirrers arranged in the main chambers said carriers adapted to travel
through the furnace and actuate the doors in their passage, substantially as herein
described.
14: In an ore roasting furnace, wheeled carriers adapted to travel within the
furnace and provided with means for agitating and advancing the ore, in combina-
tion with housings at the ends of the furnace, pivotally mounted doors in said
housings having radial arms, said carriers provided with means for actuating the
doors in their passage to impart a partial revolution and to bring the arms
successively into position to close the entrance to the furnace chambers, substantially
as herein described.
15. In an ore roasting furnace, the combination of the main roasting chambers,
the slotted partitions therein forming side chambers, carriers in the side chambers
provided with means for stirring the ore in the main chambers, a fire box having a
surrounding air space an air space below the upper main chamber provided with
means for regulating the flow of air, branch passages, leading from the air spaces
upward through the slotted partitions and discharging into the main chambers,
substantially as herein described.

page_text: 16. In an ore roasting furnace having connected roasting hearths and a supple-
mental hearth for the fusing of the roasted ore, flues or passages leading from the
supplemental hearth through the sides of the main roasting hearths, whereby
the heat from the supplemental hearth enters the main hearths at one or more
places.
17. In an ore roasting furnace, the upper and lower hearths and means for
stirring and advancing the ore therein, in combination with a supplemental hearth
upon which the roasted ore is collected in charges, and flues or passages at the sides
of the main hearths, opening at one end through the sides thereof and having their
opposite ends in communication with the heat from the supplemental hearth, whereby
the main hearths receive heat at different places along their sides, substantially as
herein described.
18. In an ore roasting furnace the upper and lower hearths and means for
advancing the ore therein, in combination with a supplemental hearth upon which
the roasted ore from the main hearth is received, and Hues or passages at the sides
of the furnace having one end in communication with the flue of the supplemental
hearth and the other end opening through the sides of the main hearths at different
places, substantially as herein described.
19. In an ore roasting furnace, the main hearth, the main flue communicating
with the interior thereof and connecting with the dust flue leading to the stack,
a supplemental hearth upon which the roasted ore from the main hearth is
received, side flues leading from the supplemental hearth through the inner sides
of the main hearths and damper-controlled flues or openings connecting the
side flues with the main dust flues from the roasting heartli, substantially as herein
described.
20. An ore roasting furnace having main hearths with a dust flue leading to the
stack, a supplemental hearth upon which the roasted ore is delivered, and damper
controlled openings or flues between the flue of the supplemental hearth and the
dust flue from the main hearths whereby the heat from the supplemental hearth
may be delivered directly to the main stack.
21. In an ore roasting furnace having roasting hearths, perforated boxes or pipes
located at or near the arches or roofs of the hearths, said boxes or pipes connecting
with a gas supply and adapted to throw a series of flame jets upon the ore at
intervals, substantially as herein described.
22. In an ore roasting furnace, the roasting hearths, the supplemental hearth
upon which the roasted ore is received, a dust flue from the main hearths con-
necting with a dust chamber leading to the stack, side flues connecting with the
flue from the supplemental hearth and entering through the inside of the roasting
hearth, a horizontal flue extending centrally along the furnace communicating
at one end with the flue from the supplemental hearth, other side flues connecting
with the central flue and leading to the inside of the roasting hearth, and a safety
door and operating means for closing the end of the horizontal central flue, and
cutting off communication with the dust chamber when desired, substantially as
herein described.
23. In an ore roasting furnace having roasting hearths, the means for stirring
and advancing the ore therein, comprising wheeled carriers, hubs or sockets extending
therefrom into the body of ore, parallel arms or rods extending from the hubs or
sockets, stirrer blades having wings bent in opposite directions and provided with
holes through which the rods or arms pass, and sleeves or spreaders having squared
ends mounted on the arms or rods between the bent portions of the blades,
substantially as herein described.
24. In an ore roasting furnace, a stirrer composed of two parallel arms supported
at one end upon a movable carrier and blades inclined with relation to the arms and
having oppositely bent wings at right angles with the arms and provided with holes
through which the latter pass, substantially as herein described.
25. In an ore roasting furnace, a stirrer blade having a portion of each side

page_text: cut away and bent at right angles in opposite directions in combination with two
parallel supporting arms separated from each other and adapted to pass through the
wings, and a movable support for the arms, substantially as herein described.
26. In an ore roasting furnace, a stirrer consisting of two parallel arms, blades
fitted at an angle between said arms, and having wings through which the arms.
pass, and spreaders having squared ends on said arms alternating with the blades
and adapted to form a rigid support for the same, substantially as herein described.
Dated this 26th day of April 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant;