Year: 1887

page_text: Date of Application, 6th Aug., 1887.
Specification Accepted, 16th Sept., 1887.
A communication from abroad by MOSES GERRISH FARMER, of Eliot, in the County
of York and State of Maine, United States of America, Electrician.
I, WILLIAM PHILLIPS THOMPSON F.C.S. M.I.M.E. of the Agency for Foreign
Patent Solicitors 6, Lord Street, Liverpool and 6, Bank Street Manchester, both in
the County of Lancaster, and 323 High Holborn in the County of Middlesex Civil
Engineer, 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 method of obtaining aluminum, and it differs
materially from the processes now in use in that the actual metal can be produced at
one operation. Various processes of smelting aluminum and other very refractory
metals have been proposed, prominent among which is the process which consists in
mixing material containing aluminum, such for example as corundum, with softer
metal such as copper in granular form, and combining the mixture with a substance
capable of receiving and retaining very high heat, such for example as broken or
crushed electric light carbon, then raising the entire mass to incandescence by the
passage therethrough of a heavy current of electricity, the result of such application
of heat being to so far reduce the aluminum ore as to form an alloy of metallic
aluminum with the other metal used as a vehicle.
By this invention this round about system is entirely eliminated and the pure metal
procured direct from its ore at one operation. The process is substantially as
follows:-
Some form of aluminum is ground up, as for instance corundum, emery or sulphate
of aluminum, and mixed with powdered gas carbon or lamp black or other rich
carbon, in such proportions as shall furnish carbon enough to combine with the
oxygen of the aluminum. This is mixed up into a stiff paste with molasses or some
rich glutinous solution of sugar or some petroleum residue. This mixture is made
into cylindrical shape as indicated in Figure 5, by forming it into a mold so as to
make it into a cylinder of suitable diameter and length, for example, three fourths of

page_text: an inch in diameter and two feet long, forming each cylinder with a hole in one end
and a tenon on the other, the holes and tenons being provided for the purpose of
joining the new carbons to the pieces partially consumed, and so avoid waste. Enough
carbon is to be mixed with the substance containing the aluminum to make the
cylinders, or as they may be called for convenience, "carbons," of fairly good
electrical conductivity.
Instead of forming the entire mass of the electrodes or charges of a mixture of
de-oxidizing material and ore as just described, a tube of carbon may be used for the
positive filled with the ore to be reduced or with a mixture of that ore and a suitable
de-oxidizing agent in the nature of fuel. A de-oxidizing jet of flame being caused to
play upon the arc, as before, in order to sufficiently elevate the temperature. The
negative electrode is preferably of ordinary carbon containing no charge and furnishes
part of the de-oxidizing agent, and the positive carbon, containing the charge, is of
a diameter sufficient to contain as much material as can be reduced by an are capable
of being maintained by the current employed. This arrangement is shown in Figure 6
of the drawings. Instead of using a tubular carbon for the positive only they may
both be made tubular, as indicated in Figure 7, in which case their relative diameters,
both exterior and interior must be so proportioned that the carbon and the charge in
each will be consumed and reduced in relatively equal proportions.
Advantage is taken of the electric arc and its known capabilities, to the fullest
extent, and with that in view the carbons, compounded as just described are each
secured in a movable frame, the two frames being arranged in juxtaposition and
provided with suitable mechanism to advance them towards each other so that the
point of separation of the carbons may be kept practically constant. A furnace is
provided, and the carbons are, by the frames just mentioned, to be projected through
lateral openings into the centre of the furnace which serves to confine the principal
portion of the heat developed, when by the passage of a powerful current of electricity
through the carbons an electric arc is established between them, as indicated in
Figures 1 and 3. A to and fro or alternating current is employed in order that the
combustion of the carbons shall be equal, and the feed mechanism thus simplified.
A continuous current may also be used, the slightly modified arrangements suitable
for which are shown in Figures 2 and 4.
In order to obtain a heat even greater than that of the electric arc, and such a
heat as readily effects the disassociation of the materials exposed to it, a stream of
mingled air and gas is injected through an opening in the side or bottom of the
furnace at right angles to the carbons, throwing said stream of air and gas directly
into the arc, and thereby elevating the temperature of the ends of the incandescent
carbons, accelerating their combustion. A liquid hydrocarbon may be used instead
of the mixture of air and gas just described, in which event it may be sprayed and
forced into the furnace, by means of a jet of steam, which mixture burns of itself with
an intense heat, but air may be used instead of steam if more convenient. Vaporized
zinc may also be substituted for the gas above referred to.
As the temperature of disassociation is reached, the oxygen leaves the aluminum
and unites with the carbon forming carbonic acid, which passes off as gas, while the
aluminum melts and drops through the bottom of the furnace into a crucible placed
to receive it.
If the ore of aluminum be pure aluminum and oxygen, no residue is left except
pure aluminum. The chloride of aluminum can be reduced in a somewhat similar
manner, but the pure aluminum in the shape of corundum is so abundant that there
is at present no need of other sources. The furnace is to be made of the most
refractory material and is closed at all points except those just mentioned. The carbons
are caused to approach by means of an electric motor which is preferably operated
by a separate battery current, the circuit of which is opened or closed by means of a
contact actuated by a solenoid included in a shunt around the arc. Of course in
using an electric current such as would ordinarily be produced from a generator using
no commutator, the solenoid will not be very strongly magnetized, but as the positive
and negative impulses are not quite equal it will be sufficiently so for the present

page_text: purpose, and it will be readily understood that when a continuous instead of an
alternating current is used, the gearing by which the carbons are fed, together will be
modified to produce the necessarily greater feed of one than the other. And also that
separate and entirely independent means may be used for feeding the carbons,
throwing the same into action in any convenient manner.
In the accompanying drawing which illustrates apparatus capable of carrying out
the invention,
Figure 1, is a diagrammatic view showing a furnace in sectional elevation together
with the carbon feeding apparatus, also the solenoid by which the circuits of the
carbon feeding motor are controlled, and additional furnaces with their electrical
connections.
Figure 2, is a diagrammatic view of a modification of the foregoing, showing a
furnace in sectional elevation together with the carbon feeding, and feed controlling
devices and additional furnaces with their electrical connections.
Figure 3 is a plan view of the furnace and carbon feeding devices.
Figure 4 is a plan view of the modified form of furnace and carbon feeding devices.
Figures 5, 6, and 7 are detail views of the cylindrical charges or carbons.
Similar letters and numbers indicate the same parts throughout.
A, is the furnace which should be of extremely refractory material, and formed
with a central combustion chamber a, into which the carbons B, B1, B2, B³, are
projected. An opening C, extends through the bottom of the furnace through which
the melted material drops into a crucible or other receptacle D, placed to receive it,
and an opening C", extends upward therefrom to permit the escape of gases. A blast
of air and gas or air and vaporized zinc, or steam and liquid hydrocarbon is thrown
into the furnace and into the are through an opening E, formed therein and at right
angles to the arc, into which opening projects the nozzle e leading from a suitable
source of supply. The carbons B, B', B2, B3, are supported respectively in the
frames F, F1, F2, F3, the outer ends of which extend to and are in juxtaposition with
each other, and are provided with racks f, f¹ƒ³, f³, the racks f, f, meshing with a
gear wheel G, which is placed between them, and which is carried upon the armature
shaft or a counter shaft suitably geared thereto of an electric motor H. The
racks, meshing with separate wheels G, G³, of different sizes, actuated by
motor H, the circuit connections from which extend through conductors, 1 and 2, to
the contacts h, h¹, from which point the motor circuit is completed through arm I,
and conductor 3, to one pole of the battery or other source of electricity J, the other
side of the circuit extending from the battery through conductor 4 to the contact h¹.
The opposite end of the pivoted lever I is connected to an iron plunger or core i, or a
central coil moving within a solenoid K, which is connected in derivation from the
main circuit by conductors 5 and 6, and acts to draw down the core i, with greater or
less force according to the resistance of the arc in the furnace.
As the operation of
smelting progresses and the carbons burn away, the resistance of the arc increases
and more and more current is forced through the solenoid until it becomes sufficiently
energized to draw down its core and complete the motor circuit through conductor 1,
contact h, arm I, conductor 3, conductor 4, contact ', and conductor 2, starting the
motor into operation and causing it to move the frames and feed the carbons together
until the resistance is diminished and the plunger I, released by the solenoid and
allowed to respond to the pull of the tension spring k, by which it is normally held
away from the contact h. The solenoid is to have so high a resistance that it will not
receive current enough to shift the lever until the resistance of the arc has con-
siderably increased by the consumption of the cylindrical charges B, B¹, or B³, B³.
The carbon cylinders are formed or provided as shown in Figures 5, 6, and 7, with a hole
at one end and a tenon at the other whereby the partly consumed pieces are enabled
to be joined to new ones, and waste avoided. The exact proportions between the
carbons and the substance containing aluminum will vary considerably, but it will be
quite safe to use one half of each, as a slight excess of carbon can do no harm and an
unnecessary amount of resistance in the charges would be only a waste of electric
energy.

page_text: A number of furnaces A, may be arranged in one circuit, and for the sake of
illustration three furnaces so arranged have been shown, each furnace being provided
with a short circuit conductor 7, extending from the main conductor 8, of one to that
of the next, and an appropriate switch L. The entire current is shunted around any
particular furnace when it is desired to recharge it, the others remaining in operation,
in this manner the operation is rendered continuous as a whole.
As the carbons are consumed the terminals of the rods F, F¹, F, F³, which are in
the form of clamps within which the carbons are secured by set screws 1, 1, will be
drawn towards each other by the action of the gear wheel G, or wheels G¹, G³, and
when they have approached as far as is desirable the main current is cut off and
shunted by closing the switch L, when by reversing the motor and closing the battery
circuit by hand or otherwise until the rods F, F¹, or F', F³, will be moved back into
their original positions when additional charging cylinders will be connected with the
pieces remaining from the preceding charge, the set screws / loosened, and the
cylinders pushed through until they meet in the centre of the furnace, after which
the switch L, is opened, and the main current will again flow through them, re-
establishing the arc, and continuing the process, which, not having been interrupted
in the other furnaces, is practically continuous.
The apparatus herein shown and described is, it will be understood, by way of
illustration, and since the improved process may be carried out with the assistance of
means and mechanism differing in many ways therefrom, it is not proposed to limit
the construction or exact arrangement of the devices shown.
Having now particularly described and ascertained the nature of the 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 herein described process of procuring aluminum which consists in
combining a substance in which it is contained with pulverized carbon, forming the
mixture into rods or cylinders, and then subjecting the extremities of said rods to the
heat of the electric arc, substantially as described.
2. The herein described process of reducing ores containing aluminum, which
consists in placing the same within a tubular electrode, and then burning the electrode
in the voltaic arc, substantially as described.
3. The herein described process of obtaining aluminum which consists in charging
an ore containing aluminum into a tubular combustible electrode, projecting said
electrode into a heat retaining chamber in juxtaposition with a second electrode, and
subjecting the said electrodes to the action of a voltaic are established between their
extremities, substantially as described.
4. The herein described process of procuring aluminum which consists in mixing a
substance containing aluminum with powdered carbon, forming the same into rods or
cylinders, projecting two of said rods into a heat retaining chamber, and then passing
an electric current through the rods, and establishing an arc between their extremities,
substantially as described.
5. The herein described method of reducing ores containing aluminum, which
consists in charging the material into a combustible tubular electrode, projecting said
electrode into a heat retaining chamber and into juxtaposition with a second com-
bustible electrode, establishing an are between the extremities of said electrodes, and
supplying a jet of de-oxidizing vapor to the point of combustion, substantially as
described.
6. The combination with a furnace, and means substantially as described for
supporting and feeding the same, of a tubular positive electrode provided with a
filling of ore containing aluminum, a negative electrode, and circuits and connections
for passing a continuous current through the electrodes consuming them together
with the filling, substantially as described.
7. The herein described process of obtaining aluminum, which consists in combining
a substance containing aluminum with powdered gas carbon and forming the same
into rods or cylinders, passing two of said rods into a heat retaining chamber and

page_text: passing an electric current therethrough so as to form an arc within said chamber,
and injecting into the arc an inflammable vapor for increasing its temperature,
substantially as described.
8. The herein described furnace consisting of a body of refractory material formed
with a central combustion chamber, an upward extending opening to permit the
escape of gases, a downward extending opening to allow the molten metal to flow
out, lateral, oppositely located openings to receive charging cylinders, charging
cylinders forming electrodes, circuit connections between the electrodes, and a suitable
source of electricity, and a motor device for feeding the electrodes towards each
other, and an additional lateral opening for an injector nozzle at right angles to the
charging apertures, substantially as shown and described.
9. The combination of a furnace having vertical and lateral apertures, of the
charging carbons entering said furnace through the lateral apertures, the spraying
nozzle entering at right angles to the carbons, means substantially as described for
automatically feeding the carbons together, said means consisting of a motor in circuit
with a separate source of electricity, and a switch lever operated by a solenoid in a
derivation from the main circuit for controlling the operations of the motor in
accordance with the resistance of the arc, as set forth.
D
1 1
1007
.
WM. P. THOMPSON & Co.,
Agents for the Applicant.