A NEW METHOD OF MANU- FACTURING IRON AND STEEL WITHOUT BEING OBLIGED TO PRODUCE PIG-IRON IN THE HITHERTO COMMON WAY; AND COMPRISES THIS ALSO, A METHOD OF SEPARATING MECHANICALLY COMBINED MINERALS, AND A WAY HOW TO OXIDATE ROAST POWDERY SUBSTANCES
Year: 1879

page_text: LETTERS PATENT to Axel Frithiof Gussander, Ironmaster, of Gammelstilla,
Torsåker, in Sweden, for the Invention of "A NEW METHOD OF MANU-
FACTURING IRON AND STEEL WITHOUT BEING OBLIGED TO PRODUCE PIG-IRON
IN THE HITHERTO COMMON WAY; AND COMPRISES THIS ALSO, A METHOD OF
SEPARATING MECHANICALLY COMBINED MINERALS, AND A WAY HOW TO
OXIDATE ROAST POWDERY SUBSTANCES."
PROVISIONAL SPECIFICATION left by the said Axel Frithiof Gussander
at the Office of the Commissioners of Patents on the 8th August 1879.
AXEL FRITHIOF GUSSANDER, Ironmaster, of Gammelstilla, Torsåker, in Sweden,
"A NEW METHOD OF MANUFACTURING IRON AND STEEL WITHOUT BEING OBLIGED TO
PRODUCE PIG-IRON IN THE HITHERTO COMMON WAY; AND COMPRISES THIS ALSO,--
A METHOD OF SEPARATING MECHANICALLY COMBINED MINERALS, AND A WAY HOW TO
OXIDATE OR ROAST POWDERY SUBSTANCES."
The new method hereinafter described is intended to separate from iron ore such
injurious or useless elements as are only mechanically combined with it, and thus
to enrich and purify the ore so as subsequently to produce from it iron and steel
free from impurities.
This enrichment and purification of ore is effected by dry process as follows:-
The ore with its rock components is reduced by means of suitable crushing
machines (either with or without previous burning) to a powder of the degree of
fineness required in each separate case. An even current of air (from a blast
engine, fan, or such like), the pressure of which is regulated according to circum-
stances is fed with the powder perfectly dried, which is spread by the current in a
room protected from other intervening. currents of air, and which may be termed
the "enriching" room; in this room the action of gravitation upon the powder
thrown into the air causes the various components of the powder to divide in falling
according to their respective specific weights, so that the heavier fall first, and the
lighter further off.
The powder is introduced through a narrow fissure, so as to fall' continuously in
measured quantities into the current of air proceeding from the mouth of the tube,
The powder may also be introduced through an inner tube inserted in the air pipe.
.

page_text: in which case it is led into the air current by the exhaustion of the air in the inner
tube. Movable partitions are fitted at the lower part of the enriching room.
These partitions are fitted at different places for different ores. The part or parts
of the divided components that are to be employed are removed through some of
the apertures in the sides (or otherwise at the bottom), and the refuse is carried
away through the other apertures. When only one kind of ore is to be treated,
the bottom may be provided with fixed cavities. Provided one or more injurious
minerals in consequence of equality in their specific weight cannot in this manner
be separated from the ore by gravitation, then it must be ascertained whether any
component is magnetic, in which case the mixed components are removed to an
apparatus, by which the magnetic powder is separated by magnetic force.
In this process the same principle is applied as in connection with the enrichment,
the powder being conveyed to an air current apparatus of the same character as
that before described, but with this difference that the powder is blown against
magnetic iron plates. A sufficient number of such plates are placed behind each
other at some distance in front of the aperture through which the air current issues,
and are moved by machine power to and fro through the air current in and out of
the enriching room, the powder adhering to the plates being scraped off when the
plates are removed from the air current.
Any of the magnetic separating apparatus already known may if desired be also
employed for the above purpose.
If no magnetic mineral is found in the above named mixed components, then the
iron ore is rendered magnetic either by means of oxidation or reduction.
Sometimes the ore is of a nature to make it more advantageous to commence the
magnetic separation immediately without previous enrichment.
This method of enriching and purifying iron ore from minerals that are
mechanically combined and mixed there with may also be applied to other ores
for the same purpose, and may be generally used for separating minerals that are
mechanically combined and mixed with each other.
If by the above process the iron ore is not freed from sulphuric minerals, it must
then be removed to the roasting furnace which is constructed as follows:-
The furnace consists of a cylinder placed either lengthwise or upright (the
cylindric form however is not altogether necessary) constructed of plates, fire-bricks,
or any other suitable substance. It is heated either from the outside with some
economical kind of fuel, carbonic oxide, or the like, to the requisite degree of heat
or from the inside, provided the products of the combustion be kept in such an
oxydising state, that they do not counteract the roasting. In this furnace a hollow
screw rotates. It is furnished with holes at intervals through which atmospheric
air with the requisite degree of pressure is blown into the furnace. The ore
powder to be roasted is continuously introduced in measured quantities, and is then
propelled in the furnace by the hollow screw with such speed as the roasting
admits of.
Sometimes it may be more advantageous to effect this roasting prior to the
enrichment. The roasting furnace is placed horizontally and heated from the
outside; it is constructd of plate, and is cylindrical in form; it has an aperture
through which the ore powder is introduced into the roasting furnace. In this
furnace it is heated and propelled by the hollow screw, being in the meantime
stirred about by the scrapers. Air is forced in through one of the extremities of
the hollow screw shaft; or provided the shaft be long through both extremities.
Through holes the air is diffused and blown into the heated powder. If requisite
the air may be heated before it is introduced into the screw shaft. The air may
likewise be introduced into the roasting furnace in another manner, for instance,
through the gable without making the screw hollow, or otherwise in both manners
simultaneously. If the threads of the screw be constructed hollow, of double plates
and provided with a few holes, air may also be introduced through them. The
roasted powder falls either directly into the reducing furnace or into a storing
'compartment. The products of the oxydation are emitted to a chimney.

page_text: This method of roasting, as also the furnace may be employed in roasting or
oxidizing any substances whatever, provided the particles be sufficiently small.
The enriched and roasted iron ore now mainly consisting of oxidised iron in the
form of powder is subsequently put into a reducing furnace, in which the reduction
is produced by means of carbonic oxide or some other reducing gas. The furnace
which is constructed either of cast iron, plates, firebricks, or some other suitable
material is heated from the outside sufficiently to give the ore powder the requisite
temperature for reduction, and the powder remains in the furnace until it is
completely reduced. In order to render the reduction more easy an apparatus for
stirring the powder is fitted inside the furnace.
The reduction may be effected either with a certain quantity of powder at a
time or continuously. In the former case the furnace may be constructed of plates,
and of a cylindrical form; it has a stirring apparatus which consists of a wheel
with bent paddles. Through a tube or channel the ore powder is introduced if
desired direct from the roasting furnace. This channel is closed during the process
of reduction by means of a damper. The inlet and outlet may be closed by valves
should it be found desirable, or the gas may be allowed to stream continuously
through the furnace. When the powder has been reduced, a trap door at the
bottom of the furnace is opened, and the powder falls out and is conducted either
directly to the smelting furnaces or to the storing compartment.
In a furnace working continuously the ore powder is continuously and in
measured quantities introduced into the furnace, where it is heated from the
outside to the requisite degree of heat, being propelled by a stirring apparatus in
the form of a screw; the reducing gas is introduced and encounters the powder.
The screw may be constructed hollow, and the reducing gas may also be introduced
through it in the same manner as the air in the hereinbefore described roasting
furnace. The furnace is constructed of the length, and the powder is propelled
with the degree of speed that is requisite to reduce the whole of the powder by the
time it arrives at the aperture, through which it falls into the storing com-
partment.
Into this storing compartment too reducing gas is introduced at some suitable
place, so that the powder while cooling may not be accessible to air. This gas
ascends into the furnace. The storing compartment may be cooled with water so
as to hasten the cooling of the powder. From the lower part of the storing
compartment the reduced iron powder is removed for further treatment. This
method of reduction may be employed with iron ore that has been sufficiently
crushed, without previous enrichment and roasting as before described provided the
ore be sufficiently rich and pure. Sometimes roasting is not needed but enrichment
is indispensable, and vice versa.
The reduced iron powder is afterwards conveyed either directly from the
reducing furnace or from the storing compartiment to suitable smelting furnaces or
crucibles, which must be kept full of reducing gas so that oxidation does not again
occur.
In these furnaces or crucibles the powder is mixed with the requisite substances
in determined quantities, and is smelted to iron or steel or the desired qualities.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Axel Frithiof Gussander in the Great Seal Patent Office on the 7th
February 1880.
AXEL FRITHIOF GUSSANDER, Ironmaster, of Gammelstilla, Forsåker, in Sweden.
"A NEW METHOD OF PRODUCING IRON AMD STEEL WITHOUT BEING OBLIGED TO
PRODUCE PIG IRON IN THE HITHERTO COMMON WAY; AND COMPRISES THIS ALSO,―A
METHOD OF SEPARATING MECHANICALLY COMBINED MINERALS, AND A WAY HOW TO
OXIDATE OR ROAST POWDERY SUBSTANCES."
In order to produce with economy superior iron and steel by the method now
commonly in use it is requisite that the ores employed should contain a sufficient
percentage of iron, and that they should be as free as possible from ingredients that
are injurious to the iron. Such injurious ingredients for the most part combine
chemically with the pig iron in the blast furnace, and subsequently either cannot
or only with the utmost difficulty be separated therefrom.
The richness or poverty of an ore depends greatly upon the quantity of minerals
and rock components that are mechanically combined or mixed with it, and the
impurities or deteriorating components found in iron and steel are chiefly derived
from minerals that were only mechanically mixed with the ores, but could not be
removed by the ordinary processes.
The new method hereinafter described is intended to separate from iron ore such
injurious or useless elements as are only mechanically combined with it, and thus
to enrich and purify the ore, so as subquently to produce from it iron and steel free
from impurities.
This enrichment and purification of ore is effected by dry process, as follows:-
The ore with its rock components is reduced by means of suitable crushing machines
(either with or without previous roasting or burning) to a powder of the degree of
fineness required in each separate case. An even current of air (from a blast or
blowing engine, fan, or such like), the pressure of which is regulated according to
circumstances, and usually for iron ore is equal to a column of about twelve millimeter
or half an inch of mercury, is fed with the powder, perfectly dried, which is spread
by the current in a room protected from other disturbing currents of air, and which
may be termed the "enriching "room. In this room the action of gravitation upon
the powder thrown into the air causes the various components of the powder to
divide in falling according to their respective specific weights, so that the heavier
ones fall first and the lighter ones further off.
Figures 1, 2, and 3 show the arrangements for this process, but the dimensions
must depend on the quantity of ore to be treated during a given time, as also on
the physical qualities of the ore. Figure 1 is a longitudinal section and partial
elevation; Figure 2, a cross section; and Figure 3, a plan view. The enriching
room is constructed of some suitable material in about the same proportions as those
shown by the Drawing. The powder is by means of some mechanical feeding
apparatus introduced through a narrow fissure a, so as to fall continuously in
measured quantities into the current of air proceeding from the mouth of the tube b.
The specifically lighter powder is carried off the air current during a longer time
and to a longer distance before it falls, but the heavier falls down earlier, and in
in this way a separation of the lighter stuff from the heavier and richer is effected.
Moveable partitions c, c, are fitted at the lower part of the enriching room to collect
the falling powder; these partitions are fitted at different places for different ores.
The part or parts of the divided components that are to be employed are removed
through some of the apertures in the sides d, d, or otherwise at the bottom, and the
refuse is carried away through the other apertures. When only one kind of ore is
to be treated the bottom may be provided with fixed cavities.
Trough collisions between the particles blown out into the enriching room some
of the lighter particles fall together with the heavier, and the separation is therefore

page_text: not quite complete, but with certain ores and for certain purposes this incomplete
separation may be sufficient. To get a more complete separation one or more air
currents are introduced below the first one and parallel with it through the apertures
61, 61, shown in dotted lines in Figures 1 and 2. These air currents, which ought
to have almost the same pressure as the first inentioned, can not keep the heavier
powder from falling through, but carries with them the lighter powder which have
by collision fallen too early from an air current above.
Instead of feeding the powder from above into the air current it may be intro-
duced through an inner tube inserted in the tuyer b (which then may have a
rounded or other suitable section) in which case it is led into the air current by the
exhaustion of the air in the inner tube.
The necessary air current or currents may also be produced by draught, for
instance, by a chimney. The enriching room is then built up in the same manner
as above described, and shown in Figures 1-3, with one or more apertures b, b', 611,
in the front end, and from the back end is an opening into the chimney. The
draught or the pressure of the air currents is regulated by dampers in the chimney.
By using the draught I need not have any blast pipes to the apertures 6, 6¹, b¹¹, but
only the tuyers.
Provided one or more injurious minerals in consequence of equality in their
specific weight caunot in this manner be separated from the ore by gravitation,
then it must be ascertained whether any component is magnetic, in which case the
mixed components are removed to a magnetic separating apparatus of some known
and suitable construction, and there separated.
If no magnetic mineral is found in the above named mixed components then the
iron ore is rendered magnetic either by means of oxidation or reduction.
Sometimes the ore is of a nature to make it more advantageous to commence the
magnetic separation immediately without previous enrichment.
This method of enriching and purifying iron ore from minerals that are.
mechanically combined and mixed therewith may also be applied to other ores for
the same purpose, and may be generally used for separating minerals that are
mechanically combined and mixed with each other.
If, by the above process, the iron ore is freed from sulphuric minerals it
must then be removed to the roasting furnace, which is constructed as follows:-
The furnace consists of a hollow cylinder placed either lengthwise or upright (the
cylindric form, however, is not altogether necessary) constructed of plates, fire-
bricks, or any other suitable substance. It is heated either from the outside with
some economical kind of fuel, such as carbonic oxide gas or the like to the requisite
degree of heat, or from the inside, provided the products of the combustion be kept
in such an oxidizing state that they do not counteract the roasting. In this furnace
a hollow screw rotates; it is furnished with holes at intervals, through which
atmospheric air with the requisite degree of pressure is blown into the furnace.
The ore powder to be roasted is continuously introduced by some mechanical
feeding apparatus in measured quantities, and is then propelled into the furnace by
the hollow screw with such speed as the roasting admits of.
In furnaces placed
lengthwise the screw is provided with scrapers or shovels, which, as they rotate,
carry the powder upwards with them, and let it fall down again, during which
process it is easily roasted by the currents of air it encounters from the hollow
screw. The furnace is constructed of the requisite length for the ore to be sufficiently
roasted during its passage through the cylinder.
-
Sometimes it may be more advantageous to effect this roasting prior to the
enrichment.
Figure 4 represents a longitudinal section, and Figure 5 à cross section of a
roasting furnace placed horizontally and heated from the outside. It is constructed
of sheet iron, and is cylindrical in form. e represents the aperture through which
the powder is introduced into the roasting furnace. In this furnace it is heated
and propelled by the hollow screw f, being in the mean time stirred about by the
scrapers g, g, of which only a few are shown in the Drawing. Air is forced- in

page_text: through one of the extremities of the hollow screw shaft, or, provided the shaft be
long, through both extremities. Through the holes h, h, the air is diffused and
blown into the heated powder. If requisite the air may be heated before it is
introduced into the spindle of the screw. The air may likewise be introduced into
the roasting furnace in another manner, for instance, through the gable or end
without making the screw hollow, or otherwise in both manners simultaneously.
If the threads of the screw be constructed hollow, of double plates, and provided
with a few holes air may also be introduced through them. The roasted powder
falls through i, either directly into the reducing furnace or into a storing compart-
ment. The products of the oxidation are emitted through the channel k to a
chimney; L, l, are the flues.
This method of roasting, as also the furnace, may be employed in roasting or
oxidising any substances whatever, provided the particles be sufficiently small.
The enriched and roasted iron ore, now mainly consisting of oxidized iron in the
form of powder, is subsequently put into a reducing furnace in which the reduction
is produced by means of carbonic oxide or some other reducing gas. The furnace,
which is constructed either of cast iron, sheet iron, fire bricks, or some other
suitable material, is heated from the outside sufficiently to give the ore powder the
requisite temperature for reduction, and the powder remains in the furnace until it
is completely reduced. In order to render the reduction more easy an apparatus
for stirring the powder is fitted inside the furnace.
The reduction may be effected either with a certain quantity of powder at a time
or continuously. In the former case the furnace may be constructed in the manner
shown in Figures 6 and 7, the former being a longitudinal section, and the latter a
cross section. The furnace, as shown in the Figures, is assumed to be constructed
of sheet iron, and of a cylindrical form. m is the stirring apparatus, which consists
of a wheel with bent paddles. Through a tube or channel n the ore powder is
introduced, if desired, direct from the roasting furnace. This channel is closed
during the process of reduction by means of one or two dampers. o is the inlet for
the reducing gas, and p the outlet. The inlet and outlet may be closed by valves
should it be found desirable, or the gas may be allowed to flow continuously through
the furnace. When the powder has been reduced a trap door 9 at the bottom of
the furnace is opened and the powder falls out, and is conducted either directly
to the smelting furnaces or to the storing compartment. r, r, denote the flues. For
certain ores it may be profitable to mix the ore with pounded charcoal. Figure 8
is a longitudinal section of a reducing furnace working continuously; and Figure 9
is a cross section of the same. Through the aperture 8 the ore powder is continu-
ously and in measured quantities introduced into the furnace, where it is heated
from the outside to the requisite degree of heat, being propelled by a stirring
apparatus in the form of a screw. Through u the reducing gas is introduced, and
encounters the powder, and through the products of the reduction are emitted.
x, x, denote the flues. The screw may be constructed hollow, and the reducing gas
may also be introduced through it in the same manner as the air in the hereinbefore
described roasting furnace. The furnace is constructed of the length and the powder
is propelled with the degree of speed that is requisite to reduce the whole of the
powder by the time it arrives at the aperture y, through which it falls into the
smelting furnaces or into a storing compartment. Into this storing compartment,
too, reducing gas is introduced at some suitable place, so that the powder while
cooling may not be accessible to air. This gas ascends into the furnace at y; the
storing compartment may be cooled with water so as to hasten the cooling of the
powder. From the lower part of the storing compartment the reduced iron powder
is removed for further treatment.
This method of reduction may be employed with iron ore that has been suffi-
ciently crushed without previous enrichment and roasting, as before described,
provided the ore may be sufficiently rich and pure. Sometimes roasting is not
needed, but enrichment is indispensable, and vice versa.
The reduced iron powder is afterwards conveyed either directly from the reducing

page_text: furnace or from the storing compartment to suitable smelting furnaces or crucibles,
which must be kept full of reducing gas, so that oxidation does not again occur.
In these furnaces or crucibles the powder is mixed with the requisite substances in
determined quantities, and is smelted to iron or steel of the desired qualities.
And having thus described and ascertained the nature of the said Invention, and
the manner in which it is or may be carried into effect, I declare that I claim,―
First. The method herein specified of separating in the dry way the mechanically
combined components of ores or minerals after having been pulverized by one or
more currents of air, which spread the powder into a room protected from other
intervening currents of air, the components of the powder then becoming divided
according to their respective specific weights in such a manner that the heavier
fall first and the lighter farther off, substantially as set forth.
Second. The method herein specified of roasting or oxidizing in a roasting furnace
pulverized substances, which are propelled through the furnace by a screw placed
lengthwise in the furnace, and provided with scrapers or shovels for stirring the
powder, and which screw may be made hollow and be furnished with holes at
intervals, through which the air is blown into the furnace, substantially as set
forth.
Third. The method herein specified of reducing by means of reducing gas, together
with pounded charcoal or without it, pulverized ores, either a certain charge at a
time or continuously in reducing furnaces, which are provided with arrangements
for stirring and propelling the ore, substantially as set forth.
Fourth. The combined process herein specified of producing iron and steel directly
from the ore by using all or any of the preparatory methods hereinbefore described,
the iron ore powder after having been reduced being smelted in crucibles or any
melting furnace, together with the substances and in such quantities which are
required for producing iron and steel of the quality required, substantially as
described.
In witness whereof, I, the said Axel Frithiof Gussander, have hereunto set my
hand and seal, this Second day of February, in the year of our Lord One
thousand eight hundred and eighty.
AXEL FRITH GUSSANDER. (L.S.)