Year: 1897

page_text: Date of Application, 28th Sept., 1897-Accepted, 11th Dec., 1897
BACCO Pcally dating
(A communication from FRANCIS H SODEN Electrician of 4617 Champlain Avenue,
Chicago, State of Illinois, United States of America).
1, ALFRED JULIUS BOULT of 111 Hatton Garden, in the county of Middlesex,
Chartered Patent Agent, 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 an improved process, and an improved apparatus by means
of which to practice the process, for the treatment of ore with the aid of electricity
to the end that the contained metal shall be separated from it in a uniformly pure
state.
This improvement is especially designed for, though not necessarily limited to,
affording a supplemental or finishing treatment of ore after it has undergone a
preparatory purifying treatment to deoxidize it and expel from it the contained salts
and acids, convert it (if iron ore) into a metallic and magnetic oxide and remove the
contained sulphur, phosphorus arsenic and other inetalloids. The now well-known
Cherry process of Ore Purification, comes, so far as my correspondent is aware, nearest
of any to completely removing impurities from ore treated according to it, with the
results above referred to. But it appears that desirably complete purification of the
ore is not attainable even by that process, so that it is peculiarly adapted to be
supplemented by the improved electric treatment, which has been particularly
devised, therefore, for such especial application, since the said Cherry process, by
serving, as it does, to convert the ore (if iron-ore) into a metallic and magnetic
condition, renders it most favorable for the application of electricity, owing to its
conductive qualities as a medium through which to relieve the ore of the remnant
of its impurities, which, in iron-ore, are designated red oxides, or the metallic base of
the metalloids. But it is found that, in addition to relieving the ore of this remnant,
this improved electric treatment effects decarburization thereof, meaning elimination
of any carbon that may be contained in it thus thoroughly purifying the metal.
The primary object may, therefore, be stated to be that of facilitating and
completing the aforesaid Cherry, or any analogous, ore-purifying process the better
to prepare the ore for smelting by freeing from it its injurious impurities.
It may be stated that the class of ore for the treatment of which this improvement
is more particularly designed is iron-ore; though it is advantageously applicable to
any kind of ore that is capable of re-oxidation, such as gold, silver, copper, lead and
other ores, after having been subjected to deoxidation, meaning after the inert or
combined oxygen in nature has been expelled, and which makes ore refractory and in
many instances impossible of reduction. By this improved treatment this oxygen is
removed, leaving the ore in a tractable condition and adapting it to take up greedily
active oxygen.
By the term inert oxygen is meant the oxygen of nature which forms a component
part of the ores. By the term active oxygen is meant, in contradistinction to oxygen
naturally in the ores, the free gas like that forming a component part of air.

page_text: This improved process consists in applying heat, through the medium of electricity
to the ore in properly divided form; in a peculiar manner to effect breaking up of the
chemical union of the impurities with the ore either after, or without previously,
driving off through the inedium of superheated air or steam its water of constitution
(hydration) and of crystallization and expelling the oxygen, which is combined with
the contained acid formations and salts, with the metal and metalloids; and also
either after, or without previously, then, deoxidizing the ore by the application
thereto of superheated hydrogen or other suitable reducing gas at sufficient heat and
pressure to permeate the mass under treatment.
As a means for practicing this improved process, I provide the apparatus
hereinafter described and illustrated in the accompanying drawings, is provided in
which―
Figure 1 is a perspective view of the improved ore-purifying apparatus; and
Figure 2 is a section taken at the line 2 on Figure 1, viewed in the direction of the
arrow, and showing, diagrammatically, the arrangement of the means for supplying
the electricity.
A is an air-tight receptacle of any suitable form, but preferably of the polygonal
shape in cross-section illustrated, and adapted to contain ore, reduced to small
fragments, say the size of hazel-nuts, which is about the smallest size necessary for
the treatment, though the ore may be pulverized. The material of which the
receptacle A is constructed should be highly refractory to withstand a high degree of
heat, and to that end it is preferred to form it of fire-brick, though plumbago crucible-
material may be employed for the purpose. The ore is fed into the receptacle A
through a pipe B, equipped with a valve-device r in a gas-escape pipe r¹, adapted
to be regulated for the escape, at any desired pressure in the receptacle, of the gases
in the latter. If it be desired to employ a condensing chamber (not shown) for the.
gaseous matter thus escaping, the same may be connected with the outlet end of the
escape-pipe r¹.
C is a pipe containing a shut-off valve q and provided with a branch C³ having a
shut-off valve q¹, and leading into the base of the receptacle below a horizontal screen
diaphragm C¹ therein divided along opposite sides of its center where it is bridged by
a cone-shaped head, into two hinged sections p and p', each having connected with it,
for dumping, a hand-wheel p2 at the front end of the receptacle. The upper sides of
the receptacle A are formed as hinged doors D, each provided with a handle o, by
which to manipulate it, and each having connected with it one hinged half of a
sectional screen C2, the sections of which extend horizontally and form a screen-
diaphragm across the upper portion of the receptacle when the doors are closed, but
opening of which latter raises the screen-sections from obstructing the fall of ore from
the pipe B into the receptacle upon the bottom diaphragm C¹. The spaces in the
receptacle A respectively below and above the perforated diaphragms C1 and C2 afford
gas-chambers D1 and D2.
E, E, are rods, of which three series are shown, one above the other, the members
of each series extending at equal distances apart, transversely across the interior of
the receptacle A, between the diaphragms, and being supported at their opposite ends
in the side-walls, from which they should be suitably insulated, unless the material
of the walls be fire-brick or other insulating material. These rods are composed of
material highly conductive of electricity, such as high-grade metal (say platinum) or
carbon, as they have to withstand intense heat.
F is an electric-current generator, preferably in the form of a dynamo of the alter-
nating current variety, having its poles connected in multiple, as shown, at projecting
ends of all the rods E through the medium of switches E¹ and E².
This particular connection, may be varied, without departure from this invention,
as to arrange some of the rods E in series to each other, but it is preferred to employ
the arrangement illustrated in order to permit currents of low potential to be used, since
thereby, the ore may be reduced to a higher degree of purification, and, consequently
to a higher metallic condition without danger of shunting too much current through
it before all the ore in the receptacle A shall have been heated to the required state.

page_text: For the purpose of regulating the heating of the conducting rods E by the current
there is interposed in the line a leading from one pole of the generator a suitable
rheostat or reactive coil F¹ (depending upon the kind of generator used) for enabling
prompt regulation, to a nicety, of the degree of heat imparted to the rods and
consequently that imparted to the ore; and where the alternating-current dynamo is
employed, in its circuit a transformer F, is also interposed.
To practice the purifying process in all its details in the receptacle A, proceed as
follows:
The ore is introduced without the admixture of any foreign substance which would
tend to promote combustion or the electro-conductivity of the mass through the pipe B
on removing its air-tight cover n and opening the doors D to raise the sections of
the perforated diaphragm C². On then fastening the cover in place and closing the
doors, to render the receptacle air-tight, the valve q is open to admit (from a suitable
source, not shown) superheated air or superheated steam under pressure into the
chamber D¹; and, the dynamo being in operation, the switches E1 and E2 are
adjusted to close the circuits they control and subject the rods to the current, which
quickly heats them, their heat being transmitted to the ore, in which they are
embedded, till it attains a red heat, at a temperature of from about 1200° F to about
1500° F. The ore is maintained in this condition, to the exclusion of atmospheric
air, until the water of crystallization and of its constitution, the inorganic oxygen
thereof and all its fugitive constituents are vaporized and expelled through the safety-
valve r.
The direction of the electric currents is on the wires x, x¹ to the switches, thence to
one end of the rods E and from the opposite ends of the latter back to the generator.
During the heating of the ore, as described, all the switches should be closed to pass
all the current, (except such portion thereof as shunts itself through the ore,) from one
side of the apparatus on the rods E to the opposite side thereof.
ore.
Thereupon the superheated air or steam supply is shut off, at the valve q and
hydrogen gas, from a suitable source (not shown) is turned on under pressure through
the branch pipe C³ to further remove and expel the impurities of the ore, while still
under subjection to the electric heat from the rods E, the electricity permeating the
ore as fast as the impurities are expelled therefrom and acting as a re-heating agent
to the ore; and this action, by following automatically the release of impurities so
closely at the very instant of such release, burns out any carbon there may be in the
This is proven by the fact that iron ore of low grade, treated in this manner, is
rendered highly metallic, and also by the fact that when the current is cut off,
as hereinafter described, from flowing directly through the series of conducting-
rods E, it will flow from one set of the rods to the other through the ore. This
is done, to ascertain whether all the impurities have been expelled by the
hydrogen and all the ore has been highly charged by electricity, by arranging
the switches to pass the electric current from the central row of the rods E to
the top and bottom rows, by closing the switches at the points numbered
2-4-6, in Figure 1, and opening them at the points-1—3—5.
The ore, thus treated to a finish, is in condition to be reduced readily to metal. This
may be accomplished by treating the ore in any suitable manner in an ordinary
smelting furnace.
Having now particularly described and ascertained the nature of this said inven-
tion and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is :-
1-The method of electrically treating ore to purify it preparatory to smelting,
which consists in subjecting it under confinement against the access of atmospheric
air to the action of superheated air and subjecting it to the action of a purifying gas,
such as hydrogen, and during the periods of such subjection, beating the said ore by
subjecting it conductively to the action of an electric current, substantially as
described.

page_text: 2-The method of electrically treating ore to purify it preparatory to smelting,
which consists in confining the ore and embedding therein unbroken resistance-con-
ductors in an electric circuit to heat the ore by contact with the electrically heated
conductors and by the resistance the ore presents to the current shunted through it,
and introducing into said ore while under such electric subjection, superheated air
and a purifying gas, such as hydrogen, substantially as described.
3-In an apparatus for treating ore, a receptacle A provided with doors D having
connected with them hinged sections of a perforated diaphragm C2 normally forming
in the receptacle an upper gas-chamber D2, a'sectional screen-diaphragın C¹ in the
lower part of the receptacle forming therein a gas-chamber D', a discharge-outlet. h
from the lower gas-chamber, a covered inlet-pipe B leading into the upper
chamber, a pressure-valve for the escape of the gases from the receptacle, va
.controlled pipes C and C¹ leading into the lower gas-chamber, series of elec
conducting-rods E extending across the receptacle to be embedded in the ore, and an
electric-current generator having the rods interposed in its circuit, substantially as
described.
Dated this 28th day of Santambor 1907
. P