IMPROVED PROCESSES AND APPARATUS FOR THE REDUCTION OF IRON AND OTHER ORES.
Year: 1883

page_text: LETTERS PATENT to Alexander Melville Clark of the firm of A. M and
-
W Clark of 53 Chancery Lane in the County of Middlesex Fellow of the
Institute of Patent Agents for an Invention of IMPROVED PROCESSES AND
APPARATUS FOR THE REDUCTION OF IRON AND OTHER ORES. Communicated
to him from abroad by J. B. Octave Thiéblemont of Paris France
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 28th November 1883.
ALEXANDER MELVILLE CLARK of the firm of A. M. and W. Clark of 53 Chancery
Lane in the County of Middlesex, Fellow of the Institute of Patent Agents
"IMPROVED PROCESSES AND APPARATUS FOR THE REDUCTION OF IRON AND OTHER
ORES [communicated to him from abroad by J. B. Octave Thiéblemont, of Paris, .
France]
..
This Invention relates to improved processes and apparatus for the direct
reduction of ores of iron and other metals such as nickel, cobalt, copper, zinc, &c,
without passing through the intermediate stage of pigs or matts. To reduce the
oxides of these metals, particularly iron, they have heretofore been brought into
immediate and direct contact with solid fuel at a high temperature, but this does
not permit of exhausting the reducing action of the Agents and introduces into the
metal a portion of all the impurities contained in the ore.
".
The present Invention has for its object the reduction of ores such as those of.
iron by means of hydrogenised and carburetted gases either together or separately
at a more or less elevated temperature without bringing the ore into contact with
solid fuel whereby the iron alone is reduced- and the silicon and more particularly
the phosphorus, remain unreduced and separate from the iron. The product.
obtained is a finely divided spongy iron which is readily oxidisable but is
constantly maintained in a reducing atmosphere or in baths that allow it to
agglomerate or melt without permitting it to become oxidised and to be afterwards
made into iron or steel.
This non-reduction of the oxides of silicon, phosphorus, sulphur, and arsenic.
when combined with oxide of iron or its gangues, by the action of reducing gases,

page_text: is the result of the processes constituting the present Invention. To this end I
first arrange a kiln for driving off the water which may be combined with the ore
and for roasting the ore more or less according to its quality; a reducing furnace
for reducing the whole of the oxide of iron to metallic iron; a reheating or welding
furnace in which the sponge
agglomerated and the gangue, and a melting furnace
for making iron in a more or less carburetted or impure condition. The above
operations may be performed either successively or simultaneously.
The accompanying drawing represents by way of example a special arrangement
of furnace in which the ore is traversed methodically by the gases as in a blast
furnace and in which their maximum useful effect is consequently obtained.
Figure 1 is a longitudinal vertical section, and Figure 2 a plan of the furnace,
Figure 3 is a vertical section at right angles to Figure 1, and Figure 4 is a section
of the reheating or welding furnace. a are the drying and roasting kilns, and b the
reducing furnace; c is a space provided for burning a portion of the still combustiblo
gases from the reducing furnace for the purposes of drying. The reduced ore is
cooled out of contact with air in a closed receptacle d. The remainder of the
combustible gases are conducted by flues e to the regenerative brick chamber g and
become inflamed by passing through f. hi are gas and smoke valves which are
alternately opened and closed. The ore is raked from the calcining furnace into the
reducing furnace at the holes and the gaseous currents are controlled by metallic
dampers m kept cooled by currents. The reheating furnace n Figure 4 has a
working door o, inlets p for air and gas for melting the gangues, a hearth q on
which the iron bathed in the slag is welded together the fore-hearth r separated
from q by a tymp s which is kept cooled and an inlet t for the reducing gases
for maintaining the heat of the fore-hearth before the gases pass into the reducing
furnace.
By this arrangement or combination of furnaces the whole of the caloric of the
carbon is utilised for the special purpose in view. The gas generator or producer
which may be provided with a blast or not, is charged with any suitable fuel; if
raw coal be used the producer would be made double, the fuel being carbonised in
the one and yielding combustible gases the gases produced in the one and which
are too highly charged with particles of carbon serving for other operations than
those of reduction, while gases depositing the least possible amount of carbon are
being produced in the other so that when the first producer has sufficiently carbonised
the fuel, it fills the purpose of the second producer which is in turn recharged with
fresh fuel and takes the place of the first one. I therefore employ one or several
gas producers, a furnace containing the ore dried and more or less roasted into
which the reducing gases are introduced at bottom after traversing the regenerating
chambers g which alternately give up their heat to and are heated by the gases.
The iron sponge formed cools in the receptacle d from which it may be conveyed
to the reheating furnace n or it may fall while hot direct into said furnace or into
the melting furnace for making cast iron or steel. The kilns a in which the ore is
dried and roasted might be separate.
The kilns having been charged with ore and started, the operation is as
follows:-
The reducing gases are heated by passing through one of the regenerators g and
enter the reducing furnace b, the heat acquired being communicated to the iron ore
in order to restore to it the excess of heat required for the reduction. The gas on
reaching the upper part still very rich in combustible products may pass off part
into the roasting kilns where it is burnt and part through the flues e to the second
regenerator which is heated while the first one is cooling; the remainder passes to
the reheating or melting furnaces
When the first regenerator is cooled down the current of gas is reversed by
means of valves h and i and the operation continued. When the ore is reduced the
product is removed at the bottom of the furnace and conveyed to the welding
furnace n and a fresh charge of ore is let down from the roasting kiln into the
reducing furnace b through suitable openings. If care be taken to maintain the

page_text: pressure of the gas in the apparatus no reoxidation can take place and in order that
the reduction may be properly effected the ores should be sorted in lumps of equal
size. The charging of furnace b and also the transferring the sponge from the
reducing to the reheating or welding furnace may be performed by means of rakes
worked by hand or by mechanical means thus ensuring continuous working. On
leaving the reducing furnace, the sponge may be compressed and it is preferable to
do so by means of a press placed between the two furnaces and in communication
with both, so that it shall always be filled with gas under pressure. The furnace n
is of the reverberatory type and of any suitable form; in it is kept in fusion any
suitable silicate wherein the sponge is bathed at such a temperature that the
particles of iron will become welded together and the gangue with the addition of
the necessary flux be melted by the currents of air and gas entering at p. In order,
to facilitate the agglomeration and union of the particles of metal, the fore hearth r
which receives the metal from the reducing furnace is protected from oxidizing
gases and separated from the sole proper by the tymp 8. The heat of this fore
hearth is maintained by the reducing gas admitted at t before passing to the
reducing furnace. As no particle of carbon is present, there can be no reduction of
the silicates phosphates and sulphates hence after the fusion of the gangues they
may be run off and the ball of iron and the furnace be washed with pure silicates
for the purpose of removing any traces of phosphorous in particular, leaving the
ball of iron capable of being drawn into bars or converted into steel or cast iron,
either in the reheating furnace itself or elsewhere. To produce steel or cast iron
after having thus washed the furnace and the metal to remove the slag, phosphorus
and sulphur, a sufficient quantity of pig iron is added to carburet the iron to the
desired degree of hardness. In this manner an eminently pure metal is obtained.
from which iron and steel of prime quality may be made. All the injurious
compounds pass away with the slag without its being indispensably basic as in the
processes hitherto employed for the treatment of phosphoric ores.
It is only
necessary that the slag in incorporating the gangue, should be perfectly fluid and
kept from contact with carbon.
こ
The spongy iron produced under the above conditions may also be melted by
means of a blast furnace, by sacrificing a portion of the iron which would reoxidize
during the operation. The iron in this case would be separated from the gangue
by liquation and it may either be run off in this condition or have the desired
degree of hardness imparted to it by known means in order to convert it into
steel.
I also directly obtain iron in a more or less impure condition by adding to the
ore while in the roasting, reducing welding or melting furnaces carbon in either a
solid or liquid form or both in any suitable proportion and according to the
temperature of the treatment and in this manner introduce without any increased
expense the matters necessary to so modify the metal as to impart to it new
qualities of hardness, tenacity and malleability not possessed by soft iron.
ر
:

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alexander Melville Clark in the Patent Office on the 28th May
1884.
ALEXANDER MELVILLE CLARK of the firm of A. M. and W. Clark of 53 Chancery
Lane, in the County of Middlesex, Fellow of the Institute of Patent Agents
"IMPROVED PROCESSES AND APPARATUS FOR THE REDUCTION OF IRON AND OTHER
ORES A communication to me from abroad by J. B. Octave Thieblemont of Paris,
France
"
This Invention relates to improved processes and apparátus for the direct
reduction of ores of iron and other metals such as nickel, cobalt, copper, zinc, &c,
without passing through the intermediate stage of pigs or matts. To reduce the
oxides of these metals, particularly iron, they have heretofore. been brought into
immediate and direct contact with solid fuel at a high temperature, but this does
not permit of exhausting the reducing action of the agents and introduces into the.
metal a portion of all the impurities contained in the ore.
The present Invention has for its object the reduction of ores such as those of
iron by means of hydrogenised and carburetted gases either together or separately
at a more or less elevated temperature without bringing the ore into contact with
solid fuel whereby the iron alone is reduced and the silicon, and more particularly
the phosphorus, remain unreduced and separate from the iron. The product
obtained is a finely divided spongy iron which is readily oxidisable but is constantly
maintained in a reducing atmosphere or in baths that allow it to agglomerate or
melt without permitting it to become oxidised and to be afterwards made into iron
or steel.
This non-reduction of the oxides of silicon, phosphorus, sulphur, and arsenic
when they are combined with oxide of iron or its gangues by the action of
reducing gases, is the result of the processes constituting the present Invention.
To this end I first arrange a kiln for driving off the water which may be combined
with the ore and for roasting the ore more or less, according to its quality; a
reducing furnace for reducing the whole of the oxide of iron to metallic iron; a
reheating or welding furnace in which the sponge is agglomerated and the gangue
melted and a melting furnace for making iron in a more or less carburetted or
impure condition. The above operations may be performed either successively or
simultaneously.
The accompanying drawing represents by way of example a special arrangement
of furnace in which the ore is traversed methodically by the gases as in a blast
furnace and in which their maximum useful effect is consequently obtained.
Figure 1 is a longitudinal vertical section, and Figure 2 a plan of the furnace;
Figure 3 is a vertical section at right angles to Figure 1, and Figure 4 is a section
of the reheating or welding furnace. a are the drying and roasting kilns, and b
the reducing furnace; c is a space provided for burning a portion of the still
combustible gases from the reducing furnace for the purposes of drying. The
reduced ore is cooled out of contact with air in a closed receptacle d. The
remainder of the combustible gases are conducted by flues e to the regenerative
brick chamber g and become inflamed by passing through f. hi are gas and smoke
valves which are alternately opened and closed. The ore is raked from the
calcining furnace into the reducing furnace at the holes and the gaseous currents
are controlled by metallic dampers m kept cooled by currents. The reheating
furnace n Figure 4 has a working door o, inlets p for air and gas for melting the
gangues, a hearth q on which the iron bathed in the slag is welded together, a fore
hearth r separated from 9 by a tymps which is kept cooled, and an inlet t for the

page_text: reducing gases for maintaining the heat of the fore hearth before the gases pass
into the reducing furnace. By this arrangement or combination of furnaces, the
whole of the caloric of the carbon is utilised for the special purpose in view. The
gas generator or producer which may be provided with a blast or not, is charged
with any suitable fuel; if raw coal be used the producer would be made double,
the fuel being carbonised in the one yielding combustible gases too highly charged
with particles of carbon which are used for other operations than those of reduction
while gases depositing the least possible amount of carbon are being produced in
the other, so that when the first producer has sufficiently carbonised the fuel, it fills
the purpose of the second producer which is in turn recharged with fresh fuel and
takes the place of the first one. I therefore employ one or several gas producers,
a furnace containing the ore dried and more or less roasted into which the
reducing gases are introduced at bottom after traversing the regenerating chambers g
which alternately give up their heat to and are heated by the gases.
The iron sponge formed cools in the receptacle d from which it may be conveyed
to the reheating furnace n or it may fall while hot direct into said furnace or into
the melting furnace for making cast iron or steel. The kilns a in which the ore is
dried and roasted might be separate.
The kilns having been charged with ore and started, the operation is as
follows:-
The reducing gases are heated by passing through one of the regenerators g and
enter the reducing furnace b, the heat acquired being communicated to the iron ore
in order to restore to it the excess of heat required for the reduction. The gas on
reaching the upper part still very rich in combustible products may pass off part
into the roasting kilns where it is burnt and part through the flues e to the
second regenerator which is heated while the first one is cooling; the remainder
passes to the reheating or melting furnaces. When the first regenerator is cooled
down the current of gas is reversed by means of valves h and i and the operation
continued. When the ore is reduced the product is removed at the bottom of the
furnace and conveyed to the welding furnace n and a fresh charge of ore is let
down from the roasting kiln into the reducing furnace b through suitable openings.
If care be taken to maintain the pressure of the gas in the apparatus no reoxidation
can take place and in order that the reduction may be properly effected the ores
should be sorted in lumps of equal size. The charging of furnace b from the
roasting kiln is performed from platform k through openings and this operation
as well as that of transferring the sponge from the reducing to the reheating or
welding furnace may be performed by means of rakes worked by hand or by
mechanical means thus ensuring continuous working. On leaving the reducing
furnace, the sponge may be compressed and it is preferable to do so by means of a
press placed between the two furnaces and in communication with both, so that
it shall always be filled with gas under pressure. The furnace n is of the
reverberatory type and of any suitable form; in it is kept in fusion any suitable.
silicate wherein the sponge is bathed at such a temperature that the particles of
ron will become welded together and the gangue with the addition of the necessary
lux be melted by the currents of air and gas entering at p. In order to facilitate
he agglomeration and union of the particles of metal, the fore hearth r which
eceives the metal from the reducing furnace is protected from oxidizing gases
nd separated from the sole proper by the tymp 8. The heat of this fore-hearth
s maintained by the reducing gas admitted at t before passing to the reducing -
urnace. As no particle of carbon is present, there can be no reduction of the
ilicates phosphates and sulphates hence after the fusion of the gangues they may
e run off and the ball of iron and the furnace be washed with pure silicates for
he purpose of removing any traces of phosphorus in particular, leaving the ball of
on capable of being drawn into bars or converted into steel or cast iron, either
the reheating furnace itself or elsewhere. To produce steel or cast iron after
aving thus washed the furnace and the metal to remove the slag, phosphorus and
phur, a sufficient quantity of pig iron is added to carburet the iron to the

page_text: desired degree of hardness. In this manner an eminently pure metal is obtained.
from which iron and steel of the best quality may be made. All the injurious
compounds pass away with the slag without its being indispensably basic as in the
It is only
processes hitherto employed for the treatment of phosphoric ores.
necessary that the slag in incorporating the gangue, should be perfectly fluid and
kept from contact with carbon.
•
The spongy iron produced under the above conditions may also be melted in a
blast furnace (four à chalumeau) by sacrificing a portion of the iron which would
reoxidize during the operation. The iron in this case would be separated from the
gangue by liquation and it may either be run off in this condition or have the
desired degree of hardness imparted to it by known means in order to convert it
into steel. I also directly obtain iron in a more or less impure condition by adding
to the ore while in the roasting, reducing welding or melting furnaces, carbon in
either a solid or liquid form or both in any suitable proportion and according to
the temperature of the treatment, and in this manner introduce without any
increased expense the matters necessary to so modify the metal as to impart to it
new qualities of hardness, tenacity and malleability not possessed by soft iron.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
hereinbefore in part recited Letters Patent is :—
1st The reduction of ores of iron or of other metals as easily reducible as iron,
by the action of reducing gases alone to the exclusion of solid carbon or with but
a very small quantity sufficient for the carburation but not for the reduction of
said ores.
2nd The simultaneous and methodical application of the gases for roasting,
reducing and melting in furnaces eommunicating but separate from each other
substantially as specified.
3rd The employment of silicates in a state of fusion for washing the metals
whose gangues are impure or but slightly fusible, as herein specified.
4th The process of treating ores in pieces of equal size and subjecting the same
to compression after reduction to avoid reoxidation as herein specified.
5th The employment of mechanical rakes for discharging the furnaces whereby
continuous working is rendered possible as specified.
6th The employment of double gas generators for obtaining gaseous products
from coal by distillation, so as to alternately produce combustible gases by
distillation and by partial oxidation of the fuel as specified.
7th The process of direct fusion of the reduced iron by sacrificing a portion of
said iron as specified.
8th The combination with the reverberatory furnace of a fore-hearth as specified
In witness whereof I the said Alexander Melville Clark, have hereunto set
my hand and seal this Twenty eighth day of May A.D. 1884.
A M CLARK (L.S.)