Improvements in Electric Furnaces and Processes of Treating Ores.
Year: 1897

page_text: Date of Application, 29th June, 1897-Accepted, 29th June, 1398
COMPLETE SPECIFICATION.
Improvements in Electric Furnaces and Processes of Treating Ores.
I, GEORGE DEXTER BURTON, a Citizen of the United States of America,
residing at 138-144, Lincoln Street, Boston, in the County of Suffolk, and
Commonwealth of Massachusetts, 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:―
My invention relates to an apparatus for desulphurizing and working metallic
ores or substances containing metal, and relates, further, to a process for refining,
purifying or discharging impurities from minerals and metallic ores, and also to
the extraction from those ores of other substances contained in them, such as
sulphur, arsenic, antimony, etc., in a liquid or semi-liquid form and by means of
which the metals that are left in the ores will be left in a state approximately
pure. It also relates to the treatment of ores known as sulphides and oxides.
My improvements relate, further, to the electrical apparatus employed and found
best adapted to the successful treatment of the class of ores herein described-
also in the method of constructing the furnace, the construction of the conduc-
tors of electricity used within the furnace and capable of conducting a current
of electricity of large volume and low pressure within the furnace, making it
possible to treat a large body of ore at one time with the electrical furnace and
regulating the temperature in the furnace to a predetermined degree during
any of the various steps involved in the operations set forth; and relates, further,
to the method of treating ores so as to expel the moisture in the ore, thereby
preventing the possibility of expansion, cracking or breaking of the furnace.
My invention relates particularly to placing a coil of pipe, a pipe or con-
ductors of electricity, in an ore working furnace and heating said ores by a
current of electricity to a predetermined heat and regulating the temperature
of the heat in the furnace and ores to the required degree to complete a successful
ore working operation. Another essential feature is the use of the coil or pipe
containing holes disposed in the coil, or in the main body and coil, or within
the coil and, not the main body of the pipe, or vice versa, causing the moisture
in the ore to be quickly expelled by the heat created by the current.
is also less liability from expansion of the ore in the furnace, preventing crack-
ing or breaking of the body of the furnace. The coil furnishing an even heat
within the furnace prevents matting or setting of the ore, and, by rotating the
coil by hand or power, the possibility of the ore setting in the furnace is practically
eliminated.
There
My improved electric furnace is illustrated in the accompanying drawings,
in which Fig. 1 is a view partly in vertical section and partly in elevation
showing my apparatus complete.
Fig. 2 is a section taken on line of Fig. 1..
Fig. 3 is a view partly in section and
In the drawings A represents the
11
partly in elevation showing modifications.
cylinder, which forms the body of my
non concluating material Thia

page_text: cylinder stands upon a base piece B, which in turn is supported by three
piers, B B B₁
The bottom C of the furnace is shaped as shown in Fig. 1, and is held in place
by sliding blocks B B. By withdrawing the blocks the bottom C of the furnace
can be lowered so as to remove the contents. An opening R is made in the
bottom piece for convenience in withdrawing the molten result of the treatment.
An orifice R' is left near the top of the furnace for the escape of gases, etc.
For the purpose of saving any of the products contained in the ores that may
be forced off by the heat from the furnace, I use a pipe P P. This pipe is made
in section so as to be readily taken apart when it is desired to remove any
product that may have condensed or otherwise formed within it. P P represent
series of deflectors placed within the pipe for the purpose of checking the free
flow of gases and floating matter and causing the latter to be deposited within
the pipe. A tank W of watery liquid receives the end of the pipe P P and
serves to condense and collect any residual that may have remained in the vapor
that passes through the pipe. Suitable valves, etc., for governing the flow
through the pipe, may be used. A suitable valve P is disposed in the pipe P P
and may be closed when the moist gases, carbon, iron, etc., are being expelled
from the furnace, and opened when it is desired to save sulphur and other bi-
products contained in the ores.
For the purpose of electrically heating and agitating the contents of the
furnace, I have the following described devices.
A hollow shaft S extends from the valve V upward through the center of
the furnace to the valve V; a collar $ holds the shaft up and allows it to turn
freely and practically air and gas tight on the upper end of the valve V. The
shaft S is turned, when desired, by the wheel H3 acting through its shaft II
and the gears Hand H. A pipe $5 leads to the valve and through it to the
hollow shaft S. The object of the pipe S5 is to allow of the admission of air
or gas to the furnace through the openings S2 S3. A hand-wheel V₁ controls
the valve V and a similar wheel V3 controls the valve V³.
The hollow shaft $ is provided with a spiral hollow flange S¹, see Fig. 1. The
interior of this spiral flange S' is connected to the interior of the shaft S, s0
that gas, or air may be introduced to it through the pipe $5.
For the purpose of electrically heating the shaft S and its flange S¹, I have
two outside electric conductors E and F. These conductors are made alike, one
being connected to the positive source of electricity and the other to the negative
source, and I will describe the lower one only. The bracket piece E connects
to the negative pole of electrical source. Upon this bracket piece the electrode E
swings and is made to fit accurately and held in close contact by tlie screw E.
To insure a good electrical contact between the conductor E and the hollow
shaft S, I have hinged by the pin E³ to the conductor bar E, a clamping piece E',
which is held by the screw E3. The positive conductor F is made and connected
in the same manner as the negative conductor E above described.
The modification shown in Fig. 3 consists in the following described parts
relating to the interior of the furnace. The central shaft is divided into two 4
parts, Land Lthe lower part L having at its top a flat disc L³ perforated as.
shown at L, the shaft being perforated as indicated at L³. The upper portion L'
of the shaft has a perforated disk N and a central opening N¹, which com-
municates with the interior of the shaft L. Openings N and N³ lead to the
interior of the shaft. The shaft L' and its connecting parts can be raised or
lowered by means of the rack T and pinion T¹, the same being operated by the
wheel T.
For convenience in working the furnace, a man-hole M is made in the top D
and is provided with a cover M¹..
The electrical apparatus best adapted to the treatment of ores by my process
is a machine producing an. alternating current of 1600 to 1800 volts. and

page_text: Sulphur, arsenic, antimony and other rebellious substances exist in many ores
and earths: By my process I place the refractory ores or substance, such as
sand containing iron, etc., and ores containing in part sulphur, antimony,
arsenic, zinc, lead, etc., in a partly closed receptacle or furnace constructed of
some non-conducting material, such as fire-clay especially prepared so as not to
absorb any of the metallic particles exuding from the ore, and I prevent the
absorption by glazing the exterior and interior surfaces of the said receptacle.
The glazing is applied after the crucible, or that part of the furnace, is formed
or shaped, and then treated in a heating furnace to set the glazing, which will
withstand a very high heat when treated in this way. The advantage in the
use of a receptacle constructed in this manner is that it is a non-conductor of
the current, will not absorb the metal, nor cause any of the metallic particles
to adhere to the walls of the said receptacle; the glazing strengthens the recep-
tacle and renders the furnace less liable to crack or break. This furnace is
provided with top and bottom coverings made of the same material and in the
same manner. These top and bottom plates are fitted closely to the body of
the furnace. A coil of pipe, such as gas pipe, or carbon, or -electrodes con-
structed of a combination of metals capable of withstanding a very high degree
of heat, such as a combination of copper and antimony, pierced with holes, may
take the place of the spiral flange Si in the receptacle containing the ore, and
be connected to the poles of the electrical source. In the treatment of such
ores as arsenical ores, lead ores, or ores containing sulphur, arsenic and other
rebellious substances, I mix coke, carbon dust, lime, and the like, in such pro-
portions as the nature of the ore requires, and then place them in the furnace.
Means are employed, as shown, to rotate the coil, or other device, in the furnace
and stir up or turn the ore when necessary. When the current is applied to
the pipe, or other part, all of that part between the outside conductors is brought
to the proper degree of heat, which heats the ore, and all of the obnoxious gases
are eliminated from the furnace through the holes S2 S3 in the pipe and are
conducted through the pipe S and valve V2 outside of the furnace. In some.
ores, such as lead or galena silver ore, the arsenic or sulphur fumes are forced
off through the opening P' and pipe P P at the top of the furnace and are de-
posited in the shape of flour of sulphur or metallic arsenic. The metallic lead,
in the lower part of the furnace, may be drawn off by tapping the spout Kat
the bottom. The condition of the ore left in the furnace varies according to the
character and nature of the formation of the ores under treatment, such, for
instance, as ore containing sulphur and iron; in this case, we would have a
desulphurized gangue, which is removed and reduced by another operation. By
placing these ores in a furnace, or retort, as described, and subjecting them while
in the furnace to the action of heat created by electricity, as described herein,
all of the impurities are eliminated, either in a gaseous form, or are driven off
in semi-liquid form. The degree of heat which I obtain by the use of this
apparatus I am unable to state, owing to my inability to find a pyrometer capable
of measuring the heat obtained.
The regulation of the current.so as to produce just the degree of heat required
and the manipulation of the current so as to quickly change the character of
the current and the degree of the heat are of great importance in the successful
treatment of ores; all of which is accomplished by the apparatus shown and
described. I have found that we require à current of comparatively small pres-
sure and large volume. With a current of large volume and low pressure I
very quickly obtain a high and even degree of heat. The quantity or intensity
of the current must be varied according to the character and quantity of the ore
under treatment. An alternating or interrupted current, such as I use, is best
adapted, because it agitates the particles of metal in the ores and causes them
to vibrate rapidly within the ore, and, where the particles are in close proximity
to one another, they cause a more rapid heating effect of the ore.
By using a minutely regulated current, I am enabled to heat the pipe, flange

page_text: or coil in the center of the furnace, to any degree of heat required and control
the heat in said pipe or coil to a predetermined temperature for a long time;
by so doing, I am enabled to heat the mass of ore slowly or quickly as the nature
of the ore requires. By making the pipe in the shape of a coil or spider, I
obtain an even heat throughout the entire mass in the furnace, which is esscu-
tial in the successful treatment of that class of ores known in mining as rebellious
or refractory ores. A pipe made of copper, instead of carbon or iron, is prefer-
able in the smelting of some kinds of ore, such as lead-galena. It prevents
adhesion of the metallic lead to the coil if a flux composed of chloride of sodium
and carbon dust is used and mixed with the ore when placed in the furnace.
The ends of the pipe protruding through the top and bottom plates or covers
of the furnace are always in view of the operator, who can determine the heat
in the conductors within the furnace, as the outside will be at a slightly lower
temperature than that part of the conductors inside of the furnace. The atmos-
phere acting only on that part of the pipe between the conductors protruding
through the furnace at each end causes it to be of a lower heat than that portion
inside the furnace excluded from the atmosphere. The cross-section of the pipe
in the center of the coil, and connected at one end with the positive pole and at
the other with the negative pole of electricity, must be in proportion to the
cross-section of the metal in the coil, so as to give an even heat in all parts of
the coil or pipe; otherwise, some parts of the coil are liable to become over-
heated, which would damage the coil. The conductors connected to the coil
or pipe at each end outside the furnace are composed of bars of copper capable
of carrying a current varying from 8000 to 12000 amperes and from 8 to 50 volts,
which is varied as desired. These copper bars are 3 inches in diameter. The
quantity of ore which can be treated at one time in this furnace varies according
to the nature and quality of the ore. Iron ore containing sulphur and other
substances where sulphur predominates from 300 to 500 lbs. can be successfully
handled in this furnace, the ore being crushed into pieces of about the size of
chestnuts.
i
A number of furnaces can be operated by the same dynamo-separately, con-
secutively, or together.
A furnace constructed in the manner herein described is useful in the
manufacture of carbide of calcium.
Refractory or rebellious ores, containing gold, silver, copper, etc., are success-
fully treated by this process. In most cases it is necessary to mix a flux with
the ore, such as chloride of sodium or bicarbonate of soda, or the like, which
causes the metal to be more readily expelled from the ores. In treating ores
which contain such obnoxious substances as sulphur, iron, and the like, I flux
the said ores, before or while in the furnace, with such proportion of bromide
of potassium as the nature of the ore requires, and then proceed with the smelt-
ing operation as described. In smelting ores containing soapstone, or a sub-
stance of a talc nature, I use bicromate of potash for a flux.
In that part of the pipe extending below the bottom of the furnace I have
placed a valve or plug V, which can be opened or closed at will of the attendant,
to admit or exclude air or oxygen from the furnace when necessary or desired.
In the smelting of such ores as contain iron; sulphur, arsenic, lead, zinc, and
the like, before placing this class of ores in the furnace it is better to close the
valve, and, when the current is applied to the pipe, coil, or electrodes, and the
substance becomes sufficiently heated to cause the material in the furnace to
pass off sulphurous or arsenical fumes or lead or zinc oxides, this temperature
is maintained until the ores or substance are freed from such as will pass off.
I then increase the heat in the furnace to the next required degree (by increasing
the volume of the current) and open the valve V in the pipe, thus admitting as
much or as little air or oxygen into the furnace as is necessary to expel the
carbon and such other impurities as remain in the ore. By the admission of
air into the furnace in this way the heat is rapidly radiated and distributed

page_text: through the remaining substance in the furnace and it is quickly heated to the
desired point. I regard this as an important discovery in the treatment of such
ores as are known as rebellious or refractory ores and in the treatment of metal or
ore where it is desired to expel the carbon from the metal. By admitting air into
the heated pipe at the bottom and through the coil in the furnace, it greatly
increases the penetrating or conducting properties of the heat throughout what-
ever substance remains in the furnace. A pipe, flange or coil, as heretofore
described, made of copper and antimony, best serves this purpose, as it with-
stands a high degree of heat and is also a good conductor of heat. In a pipe
2 inches in diameter, I would recommend an opening of only one half of an inch
through the center and coil of the pipe, as, with a small opening the walls of
the pipe will be of greater thickness, thereby furnishing more heat conducting
surface.
-
In this specification I have mentioned various kinds of flux necessary to be
combined with some ores to aid the smelting process; I do not wish to be under-
stood as confining myself to the use of the particular fluxes mentioned for all
ores carrying the same metals, as I have found, by treating over a thousand
ores from probably as many mines, that there is a great difference in the chemical
properties of rebellious or refractory ores and that it is necessary to flux such
orce as their nature and chemical properties require, in order to obtain the best
results.
Referring to the fumes forced off from the ores or substance, such as sulphur,
lead or zinc oxide, these metallic fumes rise in the furnace, when forced from
the ores by heat, and pass off through the opening Pat-the top of the furnace
and are conducted by the pipe P P into a vessel containing a watery liquid. In
passing through the pipe some of the fumes are obstructed by the projections
placed in the pipe, as shown, and the metallic particles will fall against these
projections and form a deposit in the pipe in the form of lead or zinc oxides.
In case of the sulphurous fumes (which are lighter than the zinc or lead)-
these fumes are carried further along before they are precipitated to the bottom
part of the pipe a deposit of flour of sulphur is then found; such particles of
sulphur as do not fall are conducted into the tank containing the watery liquid.
By my method of heating a body of ore by electricity in an ore working
furnace, I am enabled to produce a governable heat throughout the entire mass
of ore without the use of a fan or blower, as the action of the current is sufficient
to force off the gases, fumes, impurities. I am also able to produce a heat with-,
out imparting to the ore under treatment any foreign gases or detrimental
impurities. The apparatus forms a clean, complete, economical and successful
ore working furnace, rapid in its operation and easily cared for, all of which
has been determined after a long series of experiments.
To obtain the required heat within the furnace, the electric conductor may be
made in two parts, as shown in Fig. 3, and each end of these conductors can
be connected to opposite poles of the source of clectricity and joined in the
furnace by the ore, if it should be of high electrical conductivity, or by a piece
of carbon (not shown) in case the ore is of low. conductivity. Carbon would
not be as well as the use of a continuous conductor of ore between the two poles,
yet it would answer for some purposes, because I use a current of large volume
and low pressure. I speak of this as a modification in the construction of the
furnace, and I wish to reserve the right to all equivalent modifications which
effect the broad principles herein shown and described.
In the fume conducting pipe P P or conductor at the top of the furnace, I
may place a series of electro-magnets for attracting the metallic particles as
they pass off from such ores as contain metals of a magnetic nature, thereby
causing a separation of the magnetic particles of metal from the non-magnetic
at such point or points in the pipe P P as seems best adapted to the ore under
treatment. The pipe P P leading from the top of the furnace for conducting
the fumes, and serving as a depository for such substances as are emitted from the

page_text: "
ores,, as sulphur, metallic oxides and arsenic, is supplied with projections 1"³ P³
to obstruct the particles of sulphur, arsenic, etc., and cause them to fall and be
deposited in the pipe P P'; the lighter fumes are passed on through the pipe
and are conducted into the tank W of watery liquid W. The tank W is con-
structed of wood or other material, in which is placed a second tank or recep-
tacle, W, composed of zinc, lead, or copper. If we were to convert the sulphurous
fumes into sulphuric acid, the second tank, or lining, should be composed of
lead, to prevent action of the acid and the destruction of the tank. The pipe PP
is preferably made in sections, so that it can be readily taken apart at such
points as required to cause the separation of the flour of sulphur from the other
substances and for the purpose of quickly separating one substance deposited
from another. After the pipe has been taken apart each substance may be
removed to a separate receptacle and the pipe P P replaced and the operation
continued. As I have heretofore mentioned, where the particles that are forced
off from the ores are of a magnetic nature I place in the pipe P P, either with
or without the projections P2 P3; a series of magnets (not shown) to obstruct
such magnetic particles and cause their separation from other bi-products of a
non-magnetic nature forced off from the ores. These particles can be removed
from the pipe P P by taking it apart and removing them in the manner here-
before described: In such ores as do not contain magnetic particles, it is not
necessary to place the magnets in the pipe.
In the openings R¹I place wet clay, K K', which quickly sets under heat
and closes the openings to the furnace. When it is desired to open the open-
ings R R the clay is removed by forcing a pointed iron into the openings R R¹
from outside the furnace, thus removing the clay stopper. The furnace may
be opened and closed at will in this manner.
Where I use the word ore in this specification I desire to be understood as
applying it to substances in any form which contain metallic particles in an
untreated state.
Figure 3 represents a modification of my improved electric furnace, showing
two circular disks within the furnace composed of copper, carbon, or any good
conductor of electricity, capable of withstanding a high degree of heat. Electrodes
composed of copper and used in the treatment of some ores, such as galena or
lead ores, are preferable, owing to the low resistance of the copper, etc. I mix
the ore to be desulphurized, or worked, with the required flux, such as heretofore
described, and place the ore, or substance, in the furnace, the ore resting on the
electrode at the bottom of the furnace. The electrode at the top of the furnace
is then brought into contact with the ore and the current applied to the electrodes,
which causes, the ore, or substance, to be heated to a degree sufficient to force
off the moist gases through the holes N N in the electrode connected with the
pipe L, which gases are conducted outside of the furnace through holes N6 .N5
in the pipe L when the valve Va is opened. After the moist gases have been
expelled the valve Va. is closed and the heat is increased in the furnace, by in-
creasing the volume of the current. The desulphurization of the ores, or sub-
stance, then begins throughout all the mass in the furnace between the electrodes,
the process being continued, as heretofore described, until the ore working
operation is completed. Means are employed, as hereafter described, for feeding
downward the top electrode, so that it will always be in contact with the ore
in the furnace. The bottom electrode may be so arranged that it can be elevated
as the ore is desulphurized or treated, so that the two electrodes shall be kept
in contact with the ore in the furnace as the body of ore is decreased by the
elimination of gases, sulphur, etc., as it is necessary to have the electrodes in con-
tact with the ore so as to develop the required heat in the ore to cause a successful
operation. I use a rack and pinion to force down the electrode into contact with
the ore, and the same arrangement may be employed to raise the bottom electrode,
if required. Any mechanical equivalent may be substituted for the rack and
pinion.

page_text: In the treatment of some ores, the electrodes at the top and bottom of the mass
are preferable to the pipe or coil, and I wish it to be fully understood that one
is the equivalent of the other and that the claims and description cover either
construction, as both constructions perform the same functions and produce
the same results.
It will be observed that by raising the heat of the ore in the furnace and by
opening the valve Vs, Fig. 1, the moist gases will be eliminated-then, by closing
the valve Va and increasing the heat in the furnace, which is accomplished by
increasing the volume of the current, I raise the temperature of the heat in the
ore and desulphurize and force off the rebellious fumes and gases. If
the valves V V are then opened and air or oxygen admitted into the furnace and the
valve P in the pipe P P is closed, carbon, iron, etc., are forced off through
the pipe S to the outside of the furnace, causing the decarbonization and the
elimination of iron, etc., from the ore, or substance, in the furnace. I then close
the valves V Vs and again raising the heat, by further increasing the volume
of the current, continue the ore working operation until the metal remaining
in the ore is heated to a sufficient degree to cause it to run and leave the mass;
it can then be drawn off, before it becomes too cool, at the bottom of the furnace
through the opening R, by tapping it as above described.
When it becomes necessary to rotate the pipe S and turn or stir up the ore
in the furnace, I loosen the screws E3 and 9 on the conductors E and F and
turn the pipe S by turning the wheel H³.
Having now particularly described' and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. The process of expelling impurities and foreign substances from metallic
ores containing them by placing the ore in a partly closed furnace or receptacle
and subjecting the ore while in said furnace or receptacle to the action of an
electrical current of sufficient volume and pressure to heat the ore and eliminate
the gases.
2. The process of expelling impurities and foreign substances from metallic
ores containing them by placing the ores in a partly closed furnace or receptacle,
subjecting the ore while in said furnace or receptacle to the action of an electric
current of sufficient volume to heat the ore and eliminate the gases, and then
increasing the volume of the current to a sufficient degree to fuse the ore.
3. The process of purifying or expelling foreign substances from metallic
or mineral ores by placing said ores in a furnace and subjecting them to the
action of an electric current of sufficient volume to desulphurize them, and then
increasing the current so as to melt and liquify the remaining metal contained
therein.
4. The process of obtaining the bi-products from ores, by placing them in
an electrically heated furnace and applying the degree of heat necessary to expel
them and maintaining the heat at the proper temperature until the bi-products
are forced off and then increasing the heat and continuing the ore treating
operation until the metal leaves the ore in a molten form.
5. The combination of a partially closed furnace with an electrical current
conductor made irregular in outline and mounted rotably in the furnace, and
means for rotating the conductor to agitate the contents of the furnace to pre-
vent matting or setting of the ores, as set forth.
6. The process of refining ores by fluxing them with carbon dust, lime, coke,
or iron, and treating them in the electrically heated furnace by successively
subjecting them to currents of electricity of different volumes for producing
the required temperatures to force off such bi-products in the ore as sulphur, etc.
7. The process of desulphurizing ores or mineral's by first placing them in a
furnace containing a perforated pipe and then heating that part of said pipe
between the two poles by a current of electricity of sufficient volume and pres-

page_text: sure to heat the pipe to a temperature sufficient to cause the heating of the ores
in the furnace and force off the bi-products, such as sulphur, arsenic, etc., in a
semi-liquid form.
8. In an electric ore smelting furnace, the combination of a receptacle for
holding the ore, and a pipe therein for heating the ore in the furnace, and
apparatus for heating said pipe by a current of electricity.
9. In an electric ore smelting furnace, an electrical conductor shaped to
conduct heat to all parts of the ore in the furnace, said conductor containing
holes for the elimination of gases from the furnace during the ore treating
operation.
10. In an electric ore smelting furnace, the combination. of an ore receptacle,
with an electrical conductor placed in said receptacle, and means for rotating
the said conductor during the suiclting operation.
11. In an electric smelting furnace, the combination of an ore receptacle,
a pipe placed in said receptacle, means for rotating the pipe during the smelting
operation, and apparatus for heating said pipe by a current of electricity, and
means for regulating the heat in the pipe to a predetermined temperature.
12. The process of treating in the electric furnace refractory ores containing
gold, silver, lead, carbon, silicon, etc., which consists, first, in heating said ores
by a current of electricity to a degree sufficient to expel the metallic fumes, then
increasing the heat and admitting oxygen or air sufficient to expel the carbon,
etc., from the furnace.
13. The process of treating ores by electricity which consists, first, in heating
the same in a furnace by a current of electricity to a degree sufficient to expel
the gases and metallic fumes, then increasing the heat in the furnace so as to
fuse the metal in the ores, and then admitting oxygen into the furnace and
expelling the carbon, iron, etc., from the metal.
14. The process of treating ores by electricity which consists, first, in heating
the same by
current of electricity in a furnace to a degree sufficient to expel
the gases and metallic fumes, then increasing the heat so as to liquify the metal
in the ores, then admitting oxygen or air into the furnace sufficient to expel the
carbon from the metal, varying and controlling the admission of oxygen or air
to complete the process.
15. The process of treating ores by electricity which consists, first, in heating
the same by a current of electricity in a furnace to a degree sufficient to expel
the gases and metallic fumes, then increasing the heat to liquify the metal
in the ores, then admitting oxygen or air into the furnace sufficient to expel
the carbon from the metal, varying and controlling the admission of oxygen
or air and the degree of heat in the furnace to maintain a sufficient degree of
heat in the metal to eliminate the impurities therefrom.
16. In an electric ore smelting furnace, the process of expelling, collecting
and preserving the metallic fumes from the ores under treatment, substantially
as shown and described.
17. In electric ore working, the process of first heating the ore by a current
of electricity sufficient in volume to cause it to emit metallic funies; second,
conducting said fumes to a receptacle containing a converting substance, as
described, whereby the resultant physical elements of the fumes are converted
and preserved.
18. In electric ore smelting, the process of treating ores by electricity to
extract the moisture,, which process consists in, first, heating the ores by a
current of electricity sufficient in intensity to extract said moisture, and ex-
pelling it while the heat is less in degree than is necessary to melt the metals
in the ore.
19. The herein described process consisting, first, in heating an electric con-
ductor or conductors placed inside said furnace to a predetermined degree, to
force off vaporous gases, then increasing the heat in said conductor or conductors

page_text: to a temperature sufficient to melt and separate the metal in the material in the
furnace, substantially as set forth.
20. In an electric ore working furnace, a perforated conductor or conductors
of electricity, placed in a furnace and adapted to be heated in all parts between
two poles to a predetermined heat, and means for increasing or diminishing
the heat in said conductor or conductors at will.
21. In an electric ore smelting furnace, a valve, for regulating the admission
of air or oxygen, and a second valve, for regulating the escape of vaporous gases,
in combination with the hollow electric conductor or conductors inside said
furnace. Said valves located within said hollow conductor or conductors.
22. In an ore treating furnace, a continuous conductor or conductors for
contacting with the contents of the furnace, and adapted to be electrically con-
nected and heated to impart heat to the contents of the furnace, substantially
as, and for the purpose set forth.
23. The process of treating ores consisting of the following steps: first, sub-
jecting the ore to an even temperature, sufficient to extract and expel the watery
vapor contained in the ore; second, subjecting the ore to a higher even tempera-
ture, sufficient to force off the metallic particles and fumes contained in the
ores; third, subjecting the ore to a still higher even temperature of sufficient
degree to melt the metallic particles contained in the ore and cause them to
leave the ore in a liquid state.
24. The combination of a partially closed furnace, with an electrical current
conductor adapted to be electrically connected and made irregular in shape and
mounted rotably in the furnace and means for rotating the conductor to agitate
the contents of the furnace to prevent matting or setting of the ores, as set
forth.
25. In electric ore working, the process of treating ores in an ore heating
furnace of the character described, which consists in first heating the ores by
electricity to a heat sufficient in intensity to expel the moisture from the ore,
then increasing the heat by increasing the volume of the current and expelling
the sulphurous particles while the heat is less in degree than is necessary to
melt the metal in the ores.