IMPROVEMENTS IN THE MEANS AND APPARATUS FOR THE REDUCTION OF IRON ÛRES AND FOR PREPARING THE SAME FOR REDUCTION
Year: 1871

page_text: LETTERS PATENT to Thomas Schoenberger Blair, of Pittsburg,
Pennsylvania, in the United States of America, for the Invention of
"IMPROVEMENTS IN THE MEANS AND APPARATUS FOR THE REDUCTION OF IRON
ÛRES AND FOR PREPARING THE SAME FOR REDUCTION."
Scaled the 5th September 1871, and dated the 10th March 1871.
PROVISIONAL SPECIFICATION left by the said Thomas Schoenberger
Blair at the Office of the Commissioners of Patents, with his
Petition, on the 10th March 1871.
I, THOMAS SCHOENBERGER BLAIR, of Pittsburg, Pennsylvania, in the
United States of America, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MEANS AND APPARATUS FOR THE
REDUCTION OF IRON ORES, AND FOR PREPARING THE SAME FOR REDUCTION," to be
as follows:
Various methods and arrangements of apparatus have been proposed
for reducing iron ores to the metallic state, by bringing them either
alone or mixed with carbonaceous matter in a more or less finely
divided condition in contact with carbonic oxide and other reducing
gases.

page_text: My present Invention has for its object to effect this operation by
improved means and arrangements, whereby a more intimate and
therefore effective action of the reducing gases upon the pulverized or
granulated ore is produced than has been effected heretofore, whereby
the process can be performed upon a large scale, and at the same time a
under circumstances which give complete control over the duration (and
consequent completeness) of the treatment of the orc.
The essential feature of my Invention apart from any special apparatus
or arrangement is to bring the ore and gas together, by blowing the
latter at the requisite temperature into the former, with such an excess
of pressure as compared with the weight of the ore as shall thoroughly
agitate the latter and produce an intimate action of the gas upon the
same, or in other words it may be described as boiling the ore in hot
reducing gases until the oxygen is extracted.
It is obvious that a variety of special arrangements may be devised 1
for performing this operation. Any vessel or chamber convenient for
receiving the charge of ore and the blast of hot reducing gas and
"Bes-
for discharging the same may be employed, for example, a
semer Converter" would answer the purpose, the hot reducing gases
being blown in among the ore through apertures in the bottom of the a
converter.
But in order to work on a very large scale the operation should be
continuous, that is, the apparatus should be capable of simultaneously
receiving, treating, and discharging the ore. Such an apparatus I
provide as follows:-I construct a chamber of brickwork, the floor of:
which is furnished with openings for the passage into the chamber of the
blast of gas which is supplied underneath. These openings I prefer to
make in the form of transverse slits, and I give the floor by preference
such an inclination downwards from the receiving end to the discharging
end, and the slits such an inclination forwards from the perpendicular
as shall carry forward the ore under the action of the blast at such
speed as I may desire, though the floor may also be made horizontal and
the feeding forward of the ore be effected by the action of the inclined
gas jets only. A bin or hopper is attached to the receiving end and
presents the ore in any convenient way consistent with preventing
undue escape of gas. The ore as it meets the upward current of gas
from the apertures is tossed upward and forward, and thus travels along
through the chamber until it reaches the forward end of the floor, where

page_text: it passes down into a receptacle provided for holding it. This receptacle
is simply the enlarged base of the stack provided for conducting away
the gas (which latter may be utilized in any convenient way). The
gas introduced into the reducing chamber should be hot enough to
maintain a fair red heat in the chamber, and the receptacle for the
reduced ore which will fall into it red hot is supplied with pipes having
an internal circulation of water, so that the products shall be cooled
before being withdrawn. They are taken out by a door from the
bottom or near it on the side whenever there is sufficient accumulation
above the door to prevent ingress of air (which might take place if the
pressure of gas was off) or egress of gas.
To maintain the gas in a reducing condition and to facilitate the
operation, carbonaceous matter may be introduced, mixed with the ore,
or it may be dropped in through the roof of the reducing chamber, or
the injected gases may in their preparation be made rich in hydrocarbon
by any known means. The requisite heat for producing the desired
action of the gases upon the ore may be supplied either by heating the
reducing gases themselves on or before their entrance into the reducing
chamber, or by heating the reducing chamber itself externally. When
the oxygen has left the ferric oxide, the metallic iron will take up
carbon if the exposure be continued long enough, and this can be
avoided or obtained by the regulation of the extent of exposure to the
gases. This regulation is entirely within control, as the amount of ore
admitted, the length of the reducing chamber, and the speed of transit
through it, are all variable at will to suit the conditions of the case.
In another modification of the apparatus I arrange inside a vertical
shaft or chamber a number of superposed shelves or trays having slits
or perforations, and inclining at a moderate angle alternately from
opposite sides of the shaft, and having openings at the lower ends
through which the ore may descend from one shelf to the next below,
such openings being provided with slides or flaps so arranged as to open
only at intervals by the pressure of the ore as this accumulates, and thus
to prevent any upward escape of gas through the openings. The pul-
verized ore is introduced from a hopper at or near the top of the chamber
on to the uppermost shelf whence it is caused to descend successively
on to the shelves below, while at the same time the reducing gas is
forced in under pressure and at a sufficiently high temperature at the
bottom of the chamber, whence it is caused in ascending to penetrate

page_text: successively through the slits or perforations of the shelves and through
the layers of ore upon the same so as to agitate and act upon the ore as
above described.
The above described improved process for reducing the iron ore will
be carried to completion the more rapidly the greater the degree of
fineness to which the orc has previously been crushed, and I therefore
prefer to employ in combination with the before described process and
apparatus a machine for crushing the ore to the finest possible state of
subdivision, consisting of a series of crushing rollers so arranged at
different levels that the ore shall be caused by gravity to pass consecu-
tively through each set of rollers. The crushing rollers are all set at
different gauges increasing in fineness from the uppermost set to the
lowest, so that the ore is reduced somewhat in size in passing through
cach set of rollers. The ore is conducted from the one set of rollers to
the next over an inclined shoot having openings which are of the same
gauge as the gauge of the set of rollers into which the shoot Icads, so
that the particles of ore which have already been reduced to the degree
of fineness corresponding with that gauge will escape through the
openings of the shoot, and thus only such pieces of ore will be carried
into the next rollers as require their action. By preference the rollers
and their shoots are arranged in a zig-zag direction below each other,
so that the ore in escaping through a shoot will fall on to the next one
below, and thus any particles of ore that have at once been reduced to
a great degree of fineness on passing through the upper rollers will at
once pass down through the openings of the lower shoots either to the
bottom of the machine or until they are arrested by the shoot having
openings of a greater degree of fineness than the particles themselves.
By the above means the machine is kept from clogging. Upon passing
through the lowest set of rollers the ore is made to fall over the edge.
of a shoot from beneath which a blast of air is so directed upon it as to
separate the fine from the coarser ore by throwing the former beyond a
partition so placed as to keep the two descriptions of ore apart, and if
desired the coarser ore may be raised up to the top of the crushing
machine by chain buckets or other similar known contrivances to be
passed through the rollers a second time. Or the coarser ore may be
acted upon by reducing gases separately from the finer ore.
Although I prefer to crush the ore to a very fine state of subdivision
as above described, yet this is not absolutely necessary as the coarser

page_text: ore may also be effectually acted upon by my process by subjecting
it to the action of the gases for a greater length of time than is requisite
for the finely divided ore.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Schoenberger Blair in the Great Seal
Patent Office on the 8th September 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
SCHOENBERGER BLAIR, of Pittsburg, Pennsylvania, in the United States
of America, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of March, in the year of
our Lord One thousand eight hundred and seventy-one, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Thomas Schoenberger Blair, Her
special licence, that I, the said Thomas Schoenberger Blair, my
executors, administrators, and assigns, or such others as I, the said
Thomas Schoenberger Blair, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and
at all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United King-
dom of Great Britain and Ireland, the Channel Islands, and Isle of
Man, an Invention for "IMPROVEMENTS IN THE MEANS AND APPARATUS FOR
THE REDUCTION OF IRON ORES AND FOR PREPARING THE SAME FOR REDUCTION,"
upon the condition (amongst others) that I, the said Thomas Schoen-
berger Blair, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Thomas Schoenberger Blair, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained in and by the following statement thereof, reference being had

page_text: to the accompanying Sheet of Drawings and to the figures and letters
marked thereon, that is to say :—
Various methods and arrangements of apparatus have been proposed
for reducing iron ores to the metallic state by bringing them either
alone or mixed with carbonaceous matter in a more or less finely
divided condition in contact with carbonic oxide and other reducing
gases.
My present Invention has for its object to effect this operation by
improved means and arrangements whereby a more intimate and
therefore effective action of the reducing gases upon the pulverized
or granulated ore is produced than has been effected heretofore, and
whereby the process can be performed upon a large scale and at the
same time under circumstances which give complete control over the
duration (and consequent completeness) of the treatment of the orc.
The essential feature of my Invention apart from any special apparatus
or arrangement is to bring the ore and gas together by blowing the
latter at the requisite temperature into the former with such an excess
of pressure as compared with the weight of the ore as shall thoroughly
agitate the latter, so that the gas while acting intimately upon the ore
as a reducing agent shall at the same time act as a motor in propelling
the ore from one point where it is acted upon by the gas in the reducing
chamber to another point where it is still further acted upon, or, in other
words, it may be described as boiling the ore in hot reducing gases until
the oxygen is extracted.
It is obvious that a variety of special arrangements may be devised
for performing this operation. Any vessel or chamber convenient for
receiving the charge of ore and the blast of hot reducing gas and
for discharging the same may be employed, for example, a "Bes-
semer Converter" would answer the purpose, the hot reducing gases
being blown in among the ore through apertures in the bottom of the
converter.
But in order to work on a very large scale the operation should be
continuous, that is, the apparatus should be capable of simultaneously
receiving, treating, and discharging the ore. Such an apparatus I
provide as follows:- -I construct a chamber of brickwork the floor of
which is furnished with openings for the passage into the chamber of
the blast of gas which is supplied underneath. These openings I prefer

page_text: to make in the form of transverse slits, and I give the floor by preference
such an inclination downwards from the receiving end to the discharging
end, and the slits such an inclination forwards from the perpendicular
as shall carry forward the ore under the action of the blast at such
speed as I may desire, though the floor may also be made horizontal,
and the feeding forward of the ore be effected by the action of the
inclined gas jets only. A bin or hopper is attached to the receiving end
and presents the ore in any convenient way consistent with preventing
undue escape of gas. The ore as it meets the upward current of gas from
the apertures is tossed upward and forward, and thus travels along through
the chamber until it reaches the forward end of the floor where it passes
down into a receptacle provided for holding it. This receptacle is
simply the enlarged base of the stack provided for conducting away the
gas (which latter may be utilized in any convenient way). The gas
introduced into the reducing chamber should be hot enough to main-
tain a fair red heat in the chamber, and the receptacle for the reduced
ore which will fall into it red hot is supplied with pipes having an
internal circulation of water so that the products shall be cooled before
being withdrawn. They are taken out by a door from the bottom or
near it on the side whenever there is sufficient accumulation above the
door to prevent ingress of air (which might take place if the pressure of
gas was off) or egress of gas.
To maintain the gas in a reducing condition and to facilitate the
operation carbonaceous matter may be introduced mixed with the ore,
or it may be dropped in through the roof of the reducing chamber, or
the injected gases may in their preparation be made rich in hydrocarbon
by any known means. The requisite heat for producing the desired
action of the gases upon the ore may be supplied either by heating the
reducing gases themselves on or before their entrance into the reducing
chamber or by heating the reducing chamber itself externally. When
the oxygen has left the ferric oxide the metallic iron will take up
carbon if the exposure be continued long enough, and this can be
avoided or obtained by the regulation of the extent of exposure to the
gases. This regulation is entirely within control as the amount of orc
admitted the length of the reducing chamber and the speed of transit
through it are all variable at will to suit the conditions of the case.
In another modification of the apparatus I arrange inside a vertical
shaft or chamber a number of superposed shelves or trays having slits or

page_text: By the above means the machine is kept from clogging. Upon passing
through the lowest set of rollers the ore is made to fall over the edge of
a shoot, from beneath which a blast of air is so directed upon it as to
separate the fine from the coarser ore by throwing the former beyond a
partition so placed as to keep the two descriptions of ore apart, and if
desired the coarser ore may be raised up to the top of the crushing
machine by chain buckets or other similar known contrivances to be
passed through the rollers a second time. Or the coarser ore may be
acted upon by reducing gases separately from the finer ore.
Although I prefer to crush the ore to a very fine state of subdivision
as above described; yet this is not absolutely necessary as the coarser ore
may also be effectually acted upon by my process by subjecting it to the
action of the gases for a greater length of time than is requisite for the
finely divided ore.
On the accompanying Drawing Figure 1 shews a longitudinal section
of the form of reducing furnace which I prefer to employ in carrying my
before described improved process into practice.
A is a chamber of brickwork, the floor B of which is by preference
slightly inclined as shewn, and has formed in it a number of inclined
narrow transverse slits C, C, extending along the entire bed, which slits
communicate with the enclosed space D below the bed into which hot
reducing gases under pressure are introduced through the pipe E and
from which consequently these gases issue in the form of inclined flat
jets through the slits C into the chamber A. The pulverized ore is
introduced into the chamber A in a thin layer (capable of being
regulated by a slide F) from the hopper G; as it passes on to the floor B
it is met by the first inclined jet of heated reducing gases by which it is
thrown upward and forward, while at the same time as the ore is thus
brought into intimate contact with the gases it also becomes somewhat
O deoxidized thereby. In falling again the ore is caught up by the second-
inclined jet which acts upon it in like manner, and as it is thus gradually
conveyed from jet to jet along the entire floor the ore becomes entirely
reduced by the repeated intimate action of the gas thereon, and even-
tually falls in such reduced condition into the receptacle H. Here it
is allowed to cool, such cooling being by preference accelerated either
by providing the receptacle with a cold water jacket or by introducing
pipes into the receptacle through which cold water is made to circulate.
When sufficiently cool the ore is removed from time to time through the

page_text: door I, care being taken to preserve a sufficiently thick layer of orc
in the receptacle to prevent the egress of the reducing gas or the ingress
of air through the door. For the same purpose the hopper G should
always be kept full of ore. The pressure of the reducing gases should be
so regulated that the force with which the jets enter the chamber shall be
just sufficient to act upon and propel the ore as above described without
dispersing it unnecessarily throughout the chamber. The reducing gases
after acting upon the ore as described are conveyed away through the
shaft K, and as they may still contain more or less carbonic oxide
or other carbonaceous gases they may be further utilized for any con-
venient purpose, or they may with advantage be conveyed back through
the apparatus in which the reducing gases are generated. The heat
necessary for the proper reducing action of the gases upon the oro to
take place (which as before stated should not exceed a dull red heat)
may either be imparted to the gases themselves or the chamber A may
itself be heated by enclosing it within a heating furnace.
Figure 2 shews the before described arrangement of apparatus for
reducing the ore to the requisite more or less finely divided state.
L, L, L, &c. are a series of crushing rollers arranged in a zig-zag
direction one above the other, of which L² are set at a finer gauge
than L³, L³ at a finer gauge than L², and so on. The ore to be crushed
is introduced between the uppermost set of rollers L¹ by which it is
reduced somewhat in size, and from which it passes over the inclined
shoot M' to the second set of rollers L³, where it is crushed to a smaller
size, and in like manner the ore passes successively over the shoots M³,
&c. to the rollers L³, &c., being reduced somewhat at each stage until it
passes from the last set of rollers reduced to the requisite degree of fine-
ness. The shoots are provided with a screening surface as shewn, the
openings of which are of the same gauge as the gauge of the rollers to
which they lead, so that any ore that has already been crushed to a size
corresponding with that gauge will fall through the screen on to the
next screen below, while any portions of ore that have been crushed to
a still smaller size will fall consecutively through the screens until they
are arrested by the screen having openings of a greater degree of fineness
than themselves. In order to render the action of the screens more
effective they may have a jogging motion imparted to them by any
suitable known contrivance such as by tappets on revolving shafts
actuated by the same gearing that drives the rollers. As the pulverized

page_text: ore passes over the edge of the lowest shoot M° (which is not perforated)
it is caught by a blast of air passing from a wide nozzle N, whereby the
finer portions are conveyed beyond one or more partitions O so as to be
separated from the coarser portions which fall inside the first partition
as indicated, and which may either be subjected to the before-described
reducing process by themselves, or if desired they may be raised to the
top of the crushing apparatus and be passed through the same again.
The crushing apparatus may be used without the air blast when it is not
desired to separate the finer ore as described.
By the above-described method of subdividing the process of crushing
into several separate operations and of preventing the clogging of the
rollers by the ore that has already been reduced to powder the crushing
of the ore will be more expeditiously and perfectly effected than by the
use of only one pair of rollers for this purpose.
Having thus described the nature of my Invention, and in what
manner the same is to be performed, I wish it to be understood that what
I claim is,
First. Reducing or deoxidizing iron ore when in a more or less finely
divided condition by bringing the same into intimate contact with
reducing gases forced in among the ore at such a pressure that the gas
shall act as a motor in agitating and propelling the ore at the same time
that it effects its reduction or deoxidation, substantially as and for the
purposes herein-before set forth.
Second. Constructing apparatus or furnaces for reducing pulverized
iron ore, wherein the ore is caused to pass on to surfaces through which
jets of reducing gases under pressure are made to issue in such a manner
as to propel the ore along such surfaces, substantially as herein-before
set forth.
Third. The special construction of the orc-reducing furnace herein-
before described with reference to Figure 1 of the accompanying
Drawings.
Fourth. Constructing apparatus or machinery for crushing ore
wherein the ore is caused to pass consecutively through a series of
crushing rollers set at gauges of different degrees of fineness, means
being at the same time provided for preventing the ore that has been
crushed to a certain degree of fineness from passing through the crushing
rollers the gauge of which corresponds with such degree of fineness,
substantially as herein-before set forth.

page_text: Fifth. The special arrangement of ore-crushing machinery herein-
before described with reference to Figure 2 of the accompanying
Drawings.
In witness whereof, I, the said Thomas Schoenberger Blair, have
hereunto set my hand and scal, this Twenty-second day of
August, in the year of our Lord One thousand eight hundred and
seventy-one.