Process and Apparatus for Smelting Ores and Recovering Valuable By-products.
Year: 1898

page_text: Date of Application (in United Kingdom), 25th Apr., 1898
Complete Specification Left, 23rd June, 1898-Accepted, 25th Apr., 1899
PROVISIONAL SPECIFICATION.
Process and Apparatus for Smelting Ores and Recovering Valuable
By-products.
PAUL NAEF, Ph.D., Chemical Engineer, 15, 3rd Avenue, New Brighton, S.T.,
New York, U.S.A., do hereby declare the nature of this invention to be as
follows:-
-
This invention relates to the production of iron and other metals in blast-
furnaces.
Objects of the invention, are to combine the manufacture of pig iron in blast-
furnaces, & the manufacture of coke & by-products to recover the cyanides
formed in the blast-furnace, as such or as ammonia: to manufacture a high grade
fuel or illuminating gas, as by-products of the blast-furnace process; to economise
fuel in the blast-furnace, by oxidising some of the blast furnace gases to a greater
extent than usual; to keep the upper part of the blast furnace at a lower
temperature, and thus avoid secondary reactions; to make the production of iron,
the recovery of by-products, the coking of coal, as well as the handling of
all materials, automatic operations: to devise improved means for calcining lime-
stone for the blast furnace: to devise a mechanical system of making the smelting
charge, elevating and feeding the same into the blast furnace.
It is an established fact, that large amounts of cyanide are formed in the lower
part of iron blast-furnaces.
This cyanide is mostly destroyed in the upper part of the furnace, by the oxydis-
ing action of oxide of iron, and only a small amount is found in the gases, escaping
from the blast-furnace.
An important feature of my invention consists, in taking off hot gases from
blast-furnaces preferably before destruction of much cyanide has taken place.
These gases I utilize for the production of coke and by-products by means of a
process for which application for Letters Patent was made by me 7951/98, dated
under International Convention Sept. 7, '97.
The method consists in forcing hot gases through a column of fuel in specially
devised apparatus. The process enables the production of large quantities of
coke in a single apparatus. Preferably the coking apparatus is made of such a size,
that it will produce the coke, which the blast furnace consumes.
The hot gas is withdrawn from blast furnaces some distance above the tuyeres.
It is conducted through the openings in the periphery, which are in connection
with a brick-lined channel encircling the furnaces. The main channel is connected

page_text: to the gas inlet of the coking furnace, which is arranged at such a height, that
coke can be withdrawn at the bottom without much escape of steam. The part of
the coking apparatus below the gas entrance is used for producing ammonia by the
action of steam on the red hot coke, and for cooling the coke by means of water
and steam.
The steam rises through the coking chamber and causes decomposition of cyanide
to ammonia.
The gas which escapes from the coking apparatus, is treated for the recovery of
ammonia and also for cyanide, if no steam is used in the coking apparatus. It
is a high-grade fuel gas, which can easily be converted into illuminating gas.
Some of the incandescent gas of the blast furnace can be utilized for caleining
the lime-stone used in the smelting operations. For this purpose, an apparatus of
similar construction as the coking apparatus is used, which enables the discharge
of burnt lime without escape of gas. Cyanides contained in the hot gases will pass
through the lime kiln without decomposition.
As a large volume of gas is withdrawn from the blast furnace for coking coal,
the remainder of the gas will pass through the upper part of the furnace at a
lower speed, and there will be a more complete conversion of carbonic oxide to
carbonic acid by the action of the iron ore.
Practically all the reduction of iron oxide takes place in a space of about 15 feet
from the top of the furnace-but as the charge descends, reoxidation takes place
to a large extent by reactions:--
Fe + Co₂
=
FeO + CO, caused by too high a temperature.
High temperature causes further an increase in fuel consumption by the action
of carbonic acid on the coke, in the upper part of the furnace.
As with the new
process described, a much smaller volume of gas will pass through the upper part of
the furnace, secondary actions will take place to a much less extent.
of iron oxide will take place at a lower temperature.
The reduction
After the charge reaches the point below the off take of the incandescent gas,
it will suddenly be raised to a temperature at which the iron melts. A further
economy of fuel will be effected by the gas escaping from the blast furnace at a
much lower temperature.
If new blast furnaces are erected with my process, they can be built of smaller
height. In this case a third apparatus can be used, through which the ore is
passed, incandescent gas from the blast furnace being conducted through it at
the same time. The gas escaping from this apparatus will be mostly carbonic
acid, which can be run to waste. Cyanide will be destroyed in this apparatus by
the oxidising action of the iron oxide.
If the ore is reduced in a separate apparatus there is no necessity for passing
gas through the upper part of the blast furnace. All the gas can be withdrawn at
a lower level, and the upper part of the blast furnace, can eventually be made of
smaller height.
In the drawings Fig. 1 shows a vertical section of an apparatus designed for the
process. Figure 2 shows a vertical section of the coking apparatus in its simplest
form. In Fig. 1, No. 1, is a blast furnace which may be of any ordinary con-
struction. No. 2 is the coking apparatus. No. 3, the apparatus for caleining the
limestone by means of incandescent gases.
Incandescent gas is taken off from the blast furnace through duets 4, which
lead into a main channel 5, encircling the furnace. This channel has openings 6,
for blowing out dust if necessary.
It is connected to the coking apparatus 2, and calcining apparatus, by the
pipe 7. Water cooled dampers 8 and 9, are arranged to shut off incandescent gas
from coking and caleining apparatus if desired.
The coking apparatus consists of a shaft 10, supported on pillars 11. It is
here shown with a conical bottom 12, & doors 13, for withdrawing the coke. It
is charged with coal by mechanical means through conveyor 14.

page_text: The hot gas is introduced through the annular channel 15, and ducts 16, which
are at such a height, that the resistance to the gas is nearly the same, upwards or
downwards. The gas containing ammonia & tar leaves through pipe 17, which
conducts it to any suitable washing apparatus not shown. Water is introduced for
cooling the coke through pipe IS, and steam through pipe 19. The coke is
crushed by rollers 12" & is discharged into a storage hopper 20, which is connected
at the bottom to a conveyor 21, which delivers the coke into hopper 22.
The lime kiln 3, consists of a shaft 23, supported on pillars 24, it is charged with
limestone from hopper 25 by means of conveyor 26.
Hot gas is introduced through the annular channel 27, and ducts 28. The burnt
lime is withdrawn from the conical bottom 29, by means of door 30, into the
storage hopper 31. From 31, it is fed into 22 by conveyor 32. The iron ore is fed
into 22, from 33, by conveyor 34, and the suitable smelting mixture of lime, iron-
ore and coke is obtained by regulating the speed of the conveyors 21, 32, 34. This
smelting mixture is elevated to hopper 35, by elevator 36, which discharges into
the horizontal conveyor 37.
By this arrangement the entire operation of making the smelting charge,
elevating the same, and charging it into the blast furnace, are performed entirely
automatically. Instead of using a bell, I prefer a conveyor 38, which dispenses
entirely with manual, labour for charging.
Hopper 33, is so arranged that the iron ore can be dumped into it from railway
cars.
Water is
The water cooled dampers 8, and 9, consist of a casing 39, into which water is
run, through pipe 40, leaving through pipe 41. The damper 42, is suspended on a
pipe 43, which can be raised or lowered by any convenient means.
introduced into damper 42, through pipe, 44, and leaves pipe 43, at discharge
pipe 45.
When the coking apparatus 2, and calcining apparatus 3, are in operation,
dampers 42, are not in the reach of the intense heat, being surrounded, by the
water cooled casing 39.
In Figure 2, the coking apparatus in its simplest form, consists of a shaft 46,
which is preferably encased by sheet iron 47, an annular channel 48, encircles the
shaft through which the incandescent gases pass to the ducts 49. Coal is charged
into the apparatus from hopper 50, by conveyor 51. Ammonia is produced by
the action of steam, introduced by pipe 53, on the red hot coke, and the coke is
cooled below the entrance of the incandescent gas, by means of water introduced
through pipes 52.
In this form of the apparatus, the coke is discharged by manual labour, through
openings 54 & doors 55.
In cases where the cyanide in the blast furnace gases, is to be recovered as such,
no steam is introduced into the coking apparatus.
It may be further stated that water or steam can be introduced into the
calcining apparatus in a similar way, as is shown in coking apparatus 2, for the
purpose of converting cyanide contained in the incandescent gas into ammonia.
For the purpose of increasing the production of cyanide an alkalie can be mixed
with the coking material, as described in my Application 7953/98.
Having now described my invention what I claim as new is: -
1.The method of producing pig-iron, which consists in reducing the ore in
the upper part of a blast-furnace, at a lower temperature than usual and raising
the charge quickly in the lower part of the furnace to the melting temperature
of the metal.
2. The improved method of smelting ore in a blast-furnace, which consists in
taking off incandescent gas from the furnace some height above the tureres.
utilizing the same for producing coke, and high grade heating and illuminating
gas, and conducting the remainder of the gas through the upper part of the
furnace.

page_text: 3. The method of producing metal in a blast furnace, which consists in smelting
ore with a suitable flux in a blast furnace, withdrawing all the gases in a highly
heated state at a short distance above the tuyeres, utilizing the same for coking
coal, burning limestone and reducing ore; these processes being carried out
collectively or individually.
4. The method of producing metal, which consists in reducing the ore first in a
separate apparatus, afterwards, smelting it in a blast furnace, withdrawing all
the gas from the furnace in a highly-heated state.
5. The method of producing metal, which consists in reducing ore in a separate
furnace, afterwards smelting the same in a blast furnace, withdrawing the gases
at a short distance above the tuyeres, in a highly heated state and utilizing the same
for coking coal, burning limestone and reducing ore, these processes being carried
out collectively or singly with the smelting.
6. The combination of a blast furnace having arrangements for taking off
incandescent gases some distance above the tuyeres with an apparatus for producing
coke by said gases.
7. The combination with the coking apparatus, the calcining apparatus, and
means of producing a smelting mixture of ore, coke and lime, consisting of hoppers
and conveyors for each material.
8. The combination with a blast furnace of means for producing a smelting
mixture of coke, lime and iron ore, consisting of a storage hopper having a
conveyor at the bottom, for each material, cach conveyor delivering into one hopper
on a lower level.
9. The combination with a blast-furnace of means for producing a smelting
mixture, the means for raising the mixture into the hopper on top of the blast
furnace, and a conveyor for feeding the mixture automatically into the furnace.
10. The combination of a blast furnace, of a coking apparatus, means for
producing a smelting mixture, means for raising the mixture into a hopper on top
of the blast furnace, and means for feeding the mixture automatically into the
furnace.
11. The combination of a blast furnace, with a coking apparatus, an apparatus
for calcining limestone, means for producing a smelting mixture, means for raising
the mixture into a hopper on top of the blast-furnace, and means for continuously
feeding it into the furnace.
12. The combination with a coking apparatus of a storage hopper on a lower
level from which the coke can be discharged in regulated quantities.
Process and Apparatus for Smelting Ores and Recovering Valuable
By-products.
PAUL NAEF, Ph.D., Chemical Engineer, 15, 3rd Avenue, New Brighton, S.T.,
New York, U.S.A., 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 production of iron and other metals in blast
furnaces.
Objects of the invention are to combine the manufacture of pig-iron in blast
furnaces and the manufacture of coke and by products, to recover the cyanides
formed in the blast-furnace, as such or as ammonia to manufacture a high grade

page_text: to
fuel or illuminating gas as a by-product of the blast-furnace process;
economize fuel in the blast furnace by oxydising some of the blast-furnace gases
to a greater extent than usual; to keep the upper part of the blast furnace at a
lower temperature and thus avoid secondary reactions; to make the production
of iron and the calcination of limestone, the recovery of by-products and the coking
of coal as well as the handling of all materials automatic operations; to devise
improved means for calcining limestone for the blast-furnace; to devise a
mechanical system of mixing the smelting charge, elevating and feeding the same
into the blast furnace.
Large amounts of cyanide are formed in the lower part of blast furnaces. This
cyanide is mostly destroyed in the upper part of the furnace by the oxydising
action of oxide of iron, only a small amount being found in the gases leaving at the
top of the blast furnace.
An important feature of my invention consists in taking hot gases from blast
furnaces, preferably before the destruction of much cyanide has taken place.
These gases I utilize for the production of coke, in such a way, that any cyanide,
which the gases contain, is recovered as such or as ammonia.
ammonia and tar from the fuel is also recovered.
At the same time
The process of producing coke by means of hot gases is described in my
Appplication No. 7951/98, dated under International Convention Sept. 7, 97.
The method consists in forcing hot gases through a column of fuel in a specially
devised apparatus, which enables the production of a large quantity of coke
in a single apparatus and also the recovery of ammonia from the nitrogenous
compounds of the coke. Preferably the coking apparatus is made of such a size,
that it will produce all the coke required by the blast furnace.
The hot gases are withdrawn from the blast-furnace some distance above the
tuyeres, and are conducted through openings in the periphery into a brick-lined
annular channel encircling the furnace. From this channel a pipe conducts the
gases into an annular channel encircling the coking furnace and through ducts
into said furnace. These ducts are arranged at such a height, that coke can be
withdrawn at the bottom of the apparatus without much escape of gas or steam.
The part of the coking apparatus below the gas entrance is used for the production
of ammonia from the nitrogenous compounds of the coke by the action of steam on
the red hot coke and for cooling the coke by means of steam and water.
The steam causes further a decomposition of cyanide with formation of ammonia,
which reaction can be expressed 2NaCN + 2H,O Na 0+200+ 2NH3.
The gas leaving the coking apparatus is treated for the recovery of ammonia and
also for the recovery of cyanide, if no steam is used in the coking apparatus. This
gas is a high grade fuel gas, which is easily converted into illuminating gas by
carburetting. Some of the hot gases of the blast furnace are utilized for calcining
the limestone required for the smelting operations. For this purpose an apparatus
similar to the coking apparatus is used, which enables the discharge of the burned
lime, without escape of gas. Cyanide contained in the incandescent gases will pass
through the lime kiln without decomposition.
As a large volume of gas is withdrawn from the blast furnace for coking coal,
the remainder of the gas will pass through the upper part of the furnace at a lower
speed and there will be a more complete conversion of carbonic oxide to carbonic
acid by the action of the iron ore. In blast furnaces worked in the ordinary way
practically all the reduction of iron oxide takes place in a space of about 15 feet
from the top of the furnace, but as the charge descends re oxydation takes place to
a large extent by such reactions: Fe + CO₂- FeO + CO, caused by too high
a temperature. High temperature causes further an increase in fuel consumption
by the action of carbonic acid on the coke in the upper part of the
furnace, CO, C. 2 CO. As with the new process described, a much smaller
volume of gas will pass through the upper part of the furnace, the reduction of
iron oxide will take place at a lower temperature, and the secondary actions
described will take place to a much less extent. After the charge reaches the

page_text: point below the off-take of the incandescent gases, it will suddenly be raised to a
temperature at which the metal melts. A further economy of fuel will be effected
by the gas leaving the blast furnace top at a much lower temperature, because less
heat has to be intercepted in the upper part of the furnace.
If new blast furnaces are erected for my process, they can therefore be built of
smaller height. A separate apparatus of similar construction as the coking
apparatus can be employed for the reduction of the ore by means of hot gas from
the blast furnace. The gas escaping from this apparatus will be mostly carbonic
acid. which can be run to waste or mixed with the gases entering the coking
apparatus. No cyanide can be recovered from this apparatus, because it will be
destroyed by the oxydising action of iron oxide.
If the ore is reduced in a separate apparatus, there is no necessity for passing
gas through the upper part of the blast furnace. All the gas can then be
withdrawn at a lower level, and the upper part of the blast furnace can be
made shorter.
In the drawings which have been left with my Provisional Specification, Fig. 1,
shows a vertical section of an apparatus designed for the process. Figure 2
shows a vertical section of the coking apparatus in its simplest form.
Referring to Fig. 1, No. 1, is a blast furnace of ordinary construction. No. 2, is
the coking apparatus. No. 3, the apparatus for calcining the limestone. Hot
gases are taken from the blast furnace through ducts 4, which lead into a main
channel 5, encircling the furnace. This channel has openings 6, for blowing out
Just when necessary. It is connected to the coking apparatus 2, and the calcining
apparatus 3, by the pipe 7. Water cooled dampers 8 and 9 are arranged to shut
off the hot gases from the coking and calcining apparatus if desired.
The coking apparatus consists of a shaft 10, supported on pillars 11. It is
here shown with a conical bottom 12, and doors 13, through which the coke is
discharged. It is charged with coal by conveyor 14 from the hopper above. The
hot gas is introduced through the annular channel 15, and ducts 16. The gas
containing ammonia and tar leaves through pipes 17, which conducts it to any
suitable washing apparatus not shown.
The part of the coking apparatus below the ducts 16, is used for producing
ammonia from the nitrogenous compounds of the coke, by the action of steam and
for cooling the coke. The steam is introduced through numerous pipes 19, and
the water through pipes 18.
The coke is crushed and continuously discharged by the rollers 12ª. It drops
into the storage hopper 20, which is connected at the bottom to a conveyor 21,
which delivers the coke into hopper 22.
The inlets of gas and steam to the coking apparatus, are arranged at such a
height, that the resistance to the passage of gas upwards and downwards is about the
same. Coke can therefore be withdrawn from the bottom without escape of gas or
steam.
In regard to the coking process and apparatus therefore, reference is made to my
Applications 7951, 7952, 7953/98, dated under International Convention,
7 Sept. 97.
The lime kiln 3 consists of a shaft 23 supported on a pillar 24: it is charged
with limestone from hopper 25 by a conveyor 26. Hot gas from the blast
furnace is introduced through the annular channel 27 and ducts 28. The burnt
lime is withdrawn from the conical bottom 29, through the doors 30, into the
storage hopper 31.
From hopper 31, it is fed into hopper 22, by conveyor 32. The iron ore is
fed into storage hopper 22 from 33 by conveyor 34, and the suitable smelting
mixture of lime, iron-ore, and coke is obtained by regulating the speed of the
conveyors 21, 32, 34.
This smelting mixture is elevated into hopper 35 by the clevator 36, which
discharges into the horizontal conveyor 37. The latter discharges the smelting

page_text: mixture into hopper 35, from which it is fed into the blast furnace, by means of
conveyor 38.
By this arrangement the operations of coking, the caleining of the limestone,
making the smelting charge, elevating the same, and charging it into the blast-
furnace are performed automatically. Instead of using a bell for charging the
blast furnace, a conveyor 38, is used, which dispenses entirely with manual labour
for charging.
Hopper 33 is so arranged, that the iron ore can be dumped into it from railway
cars or from suitable ore bins.
The water cooled dampers 8 and 9 consist of a casing 39, into which water is run
through pipe 40, and leaving through pipe 41. The damper 42, is suspended on
pipe 43, which can he raised or lowered by any convenient means. Water is
introduced into the damper 42, through the pipe 44, and leaves pipe 43, at
discharge pipe 45.
When the coking apparatus 2, and calcining apparatus 3, are in operation, the
dampers 42 are not in the reach of the intense heat, being surrounded by the water
cooled casing 39.
In Fig. 2, the coking apparatus consists of a shaft 46, which is preferably encased
with sheet iron 47. An annular channel 48, encircles the shaft, through which the
incandescent gases pass to the ducts 49. Coal is charged into the apparatus from
hoppers 50, by conveyor 51. Ammonia is produced in the part of the apparatus
below the entrance of the hot gas by the action of steam introduced through
numerous pipes 53, on the red hot coke. The coke is further cooled by means of
water introduced through pipes 52. In this form of the apparatus the coke is
discharged by manual labour, through openings 54 and doors 55.
If the cyanide in the blast furnace gases, is to be recovered as such, no steam
is introduced into the coking apparatus. In such cases cyanide is absorbed from
the gases leaving the coking apparatus. It may be further stated, that steam
can be introduced into the lower part of the calcining apparatus 3, in a similar way
as is shown in the coking apparatus 2, for the purpose of converting the cyanide
contained in the blast furnace gases into ammonia.
For the purpose of increasing the production of cyanide an alkali can be mixed
with the coking material as described and claimed by me in Application 7953/98.
It is an important feature of my invention that it enables the use of bituminous
slack at iron blast furnaces without interfering with the capacity of said furnaces.
The general construction of the apparatus can be varied as the case may require
to obtain the best results in the process, without departing from the spirit of my
invention.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:―
1. The method of producing pig iron which consists in reducing the ore in the
upper part of a blast furnace, at a lower temperature than usual and raising the
charge quickly in the lower part of the furnace to the melting temperature of
the metal.
2. The method of producing pig iron, gas and by-products, which consists in
smelting ore in a blast furnace, taking hot gas from said furnace some distance
above the tuyeres, utilizing the same for producing coke and high grade heating
and illuminating gas and by-products and conducting the remainder of the gas
through the upper part of the furnace.
3. The improved method of producing metals, gas and by-products, which
consists in smelting ore with a suitable flux in a blast furnace, withdrawing hot
gases in a highly heated state at a short distance above the tuyeres, utilizing the
same for coking coal.
4. The method of producing metal, which consists in reducing the ore first in

page_text: a separate apparatus, afterwards smelling it in a blast furnace, withdrawing the
said gas from the furnace in a highly heated state.
5. The method of producing metal, which consists in reducing ore in a separate
apparatus afterwards smelting the same in a blast furnace withdrawing the gases
at a short distance above the tuyeres, in a highly heated state, and utilizing the
same for coking coal, burning limestone and reducing ore, these processes being
carried out collectively or singly with the smelting.
6. The improvement in the manufacture of pig iron, which consists in produc-
ing the coke required by the blast furnace continuously from bituminous coal in
a coking apparatus which works in connection with said blast furnace, whereby
rich gas and valuable by-products are produced.
7. The combination of a blast furnace having arrangements for taking off
incandescent gases some distance above the tuyeres with an apparatus for producing
coke by said gases.
8. The combination with a blast furnace of the coking apparatus the calcining
apparatus and means of continuously producing a smelting mixture of ore, coke,
and lime, consisting of hoppers and conveyors for each material.
9. The combination with a blast furnace of means for producing a smelting
mixture of coke, lime and iron ore, consisting of a storage hopper, having a
conveyor at the bottom for each material, each conveyor delivering into one hopper
on a lower level.
10. The combination of a blast furnace of means for producing a smelting
mixture, the means for raising the mixture into said hopper on top of the blast
furnace, and a conveyor for feeding the mixture automatically into the furnace.
11. The combination of a blast furnace of a coking apparatus, means for
producing a smelting mixture, means for raising the mixture into a hopper on
top of the blast furnace, and means for feeding the mixture automatically into
the furnace.
12. The combination with a blast furnace with a coking apparatus, an apparatus
for calcining limestone, means for producing a smelting mixture, means for raising
the mixture into a hopper on top of the blast furnace and means for continuously
feeding it into the furnace.
13. The combination with a coking apparatus of a storage hopper on a lower
level from which the coke can be discharged in regulated quantities.
1441 day of Tune 1000
PAUL NAEF,
Applicant.