Improvements in the Process of Smelting Ore and in Electric Furnaces therefor.
Year: 1899

page_text: Date of Application, 12th Dec., 1899-Accepted, 13th Jan., 1900
COMPLETE SPECIFICATION.
Improvements in the Process of Smelting Ore and in Electric Furnaces
therefor.
I, FRANCIS EDWARD HATCH, Electrical Engineer, of Norway, Dickson County,
State of Michigan, United States of America, 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 a process for smelting ore and to improvements in
electric furnaces and especially to that class known as incandescent, in contra-
distinction to those wherein the electric arc is employed for smelting ores, metals
or the like.
The object of my invention is to provide a means wherein the entire charge
of material to be smelted is uniformly subjected to the heating effect of the
current without being traversed by the current, so that the work done in the
furnace is more constant than is possible to be maintained when the current is
caused to pass directly through the charge. In the latter event the electric re-
sistance of the charge varies with its changing condition, and the path through
the charge is in the most direct line of least resistance, the result of which is
to overheat, or volatilize a portion of the charge, while a larger portion thereof
is not influenced by the thermic effect of the current.
To overcome these objections I heat a refractory conductor to a high state of
incandescence, by the electric current, and then pass the conductor, while so
heated under the charge to be smelted, or cause the charge to cover or surround
the incandescent conductor until the heat contained therein has been imparted to
the charge. By heating a series of like conductors and passing them in succession
into the charge, I find that the charge can be more uniformly heated, and that the
resistance through the various conductors is more constant than obtains when the
charge itself forms a part of the electric path.
With these and other objects in view my invention consists in a new method
of, and furnace for smelting metal, ores and the like, by the application of an
electric current wherein a refractory electric conductor is heated to a high state
of incandescence, and then placed in intimate contact with the material to be
effected.
In the accompanying drawings, which form a part hereof, I have shown one
form of furnace by which my new method may be carried into effect.
Fig. 1 is a cylinder of refractory material, such as fire clay or the like.
Fig. 2 is a cross section through line 2 of Fig. 1.
Fig. 4 and Fig. 5 are detailed views of the carbon conductors, which are con-
tained within the cylinder.
Fig. 3 is a pan view, showing the manner in which the terminals of the various
carbon conductors are connected together.
Fig. 6 is a reduced view of the assembled parts constituting a rotary furnace.
Fig. 7 is a broken away end of same, showing the roller guides upon which
the cylinder A is supported.

page_text: Fig. 8 is a diagram of connections between the carbon sections anu
mutator.
CONT
Referring to Fig. 1A is a cylinder of refractory material, provided with open-
ings a in its circumference, through which carbons B having terminal pieces b
and pass, and which are connected together on the exterior thereof, as shown
in Fig. 2 and Fig. 3, in this manner forming a terminal for all the carbons in
each of the respective sets.
The car-
The cylinder shows places for six sets with 16 carbons in each set.
bons, when placed within the cylinder as shewn, form a complete lining, consisting
of 96 carbons, each presenting a maximum of surface.
Fig. 6 shows my furnace complete and ready for operation, with the exception
that for the sake of clearness I have not shown the carbons B in place.
A is the cylinder, into which the ore, or the like is placed.
A is a cap which covers one end having a hole a through the center, for
and admission of air.
escape of gases
The cylinder A is held against the face plate, or flange a¹ of the shaft a² by
means of bolts a³, which pass through the face plate on the shaft and through
the plate a on the front end of the cylinder A, they also pass through the
rings a5 and a. The rings a5 and a are designed to surround the cylinder A,
and are adapted to engage with the rollers a7 and a³. By means of this arrange-
ment the cylinder is supported in a horizontal position while it is being rotated.
Attached to the face plate al is a six part commutator a³, to each section of
which one of the terminal carbon sections in the cylinder are respectively con-
nected. A brush a0, which bears upon the commutator a is held in position by
the insulated stud a". The latter forms one electrical terminal of my furnace.
The shaft is journaled in bearing. The pulley a3 affords a means by
which the shaft and cylinder may be rotated.
The electric wires may be connected to a stud all and connection a¹ on the
standard ag
Fig. 8 is a diagram of the connections between the carbon sections of the
cylinder and the commutator.
manner.
C represents the carbons within the cylinder A, and D represents the com-
mutator. The carbon sections I have numbered from 1 to 16 inclusive, and corre-
sponding commutator sections are designated in same
Connecting
wires numbered to correspond with the carbon and commutator sections connect
the respective sections together. One end of each of the carbon sections is con-
nected to the shaft 2 by means of wires 10.
The arrows show the electric circuit and also the direction of rotation of the
cylinder and commutator.
The operation of my device is as follows:
Iron ore, or the like, with the necessary flux and reducing agent, such as carbon
and lime, when the furnace is to be used for smelting iron ore, is placed within
the cylinder A until it is filled about even with the lower edge of the hole a¹6,
the material is then in contact with the three lower sets of carbons, Fig. 2.
The circuit is attached to the terminals a¹.
Now referring to Fig. 8, it will be seen that the current will flow from brush a 10
through wires 3 and 4, through the respective carbon sections 3 and 4 and thence
to the shaft to the opposite wire of the supply current, completing the circuit
through the machine."
This condition of parallel circuit only lasts for a very short time while
brush a is in contact with both commutator sections 3 and 4. Section 4 has
been heated by the current and the cylinder is now being rotated, while the hot
section 4 is approaching lowest position, and the ore, flux etc. contained within
the cylinder is being piled upon it by the effect of the rotation.
Section 3 will be heated next, when it in turn will pass under the ore, as above
described.

page_text: They will all be in like manner and in consequence heated and passed into
and out from under the ore on the opposite side of the cylinder.
Powdered or granular carbon and lime may be placed in the furnace with the
iron ore.
The iron is contained in the ore in a state of oxide, that is, in chemi-
cal combination with oxygen. This element must be removed in order to obtain
the iron in the metallic state, this could be readily done by the carbonic gases
and heat of the furnace, if the ore consists of oxide of iron only, but the presence
of clay in the iron ore introduces a difficulty. Clay consists of alumina and
silica and can not be readily melted alone. In the presence of oxide of iron the
clay combines chemically and melts to a liquid, black, glassy substance, con-
taining most of the iron, but if lime, (preferably quick lime) be mixed with the
ore, the clay will combine with it instead of combining with the oxide of iron.
The iron will then be left clear of the silica and alumina.
The air admitted into the furnace consists of one part oxygen and four parts
nitrogen, coming in contact with the glowing carbon granules combines quickly
forming a carbonic acid gas containing eight parts oxygen and three parts of
carbon, it will give up one half of its oxygen to the heated carbon in turn, and
becomes carbonic oxide gas, which consists of four parts of oxygen and three
parts carbon. When the carbonic oxide gas meets the red hot ore containing
oxide of iron, it regains sufficient oxygen to convert it into carbonic acid, thus
reducing the iron to a metallic liquid state.
It will be noticed by referring to Figs. 2 and 8 that while the current is heating
section 3, for instance, that there is no ore in contact with this carbon section,
and that the entire current is utilized in heating this section and is not directed
through the ore. Therefore, a more uniform resistance is maintained, and a
constant, regular load on the dynamo will result.
The cylinder may be revolved slowly at a constant speed, or in impulses by
any suitable mechanism. By this operation the ore is tumbled over and covers
the carbon sections that are approaching the lowest position, at the same time
these said carbon sections have just been passed out from the pyro electric effect
of the electric current and are in a state of incandescence. The charge absorbs
the heat of the incandescing carbons and is again tumbled over and covers the
next set of incandescing carbons, as they approach the lowest position. This
operation is repeated as the cylinder is revolved, each set of carbons being heated
and passed in turn into contact with the ore.
In the course of time the ore will be smelted, when iron may be drawn out
through the hole a¹5….
It is evident that the carbon section B may be made in one solid piece, but I
prefer to make them as shown, as in this form they present more surface and they
may be more easily and cheaply replaced in sections than in one piece.
The brush a10 may be rotated around the commutator to any point so as to
control the point where the carbon sections B shall leave the electric circuit.
My furnace may be used to greater advantage for smelting iron ore, where it
is desirable to heat the ore to a degree sufficient to separate the iron, but not
to such a high temperature as to volatilize the iron.
The cylinder of my furnace may be made of fire clay, or other refractory
materials, such as that contained in fire brick, crucibles and the like.
From the above description, taken in connection with the accompanying draw-
ings, it will be seen that I have provided an electric furnace by which ore, metal
or the like, may be heated indirectly by the effect of the electric current to a
uniform temperature, and that the material so heated does not at any time form
a part of the electric circuit, and in this particular I believe my furnace differs
from all others heretofore known.
I desire it understood that I do not limit myself to any specific details of con-
struction, nor to the construction of any particular form of furnace, as my
invention consists in the process, or method, of melting metal ores, or the like,
in the manner hereinbefore shown and described, and I reserve to myself the

page_text: right to all of the uses of my process that will fairly fall within the spirit and
scope of my invention.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is ;-
1. A process for treating ore, metal or the like, which consists in heating a
refractory electric conductor to a high state of temperature by the direct appli-
cation of an electric current, withdrawing the current and subjecting the material
to be treated to the thermic effect of the said electric conductor, substantially as
set forth.
2. A process for smelting ore, metal or the like, which consists in heating a
refractory electric conductor to a state of incandescence with an electric current,
withdrawing the current, and then placing the incandescing conductor in inti-
mate contact with a material such as ore, or the like, associated with a suitable
reducing agent, whereby the said material is smelted, substantially as set forth.
3. A process for smelting ore, metal or the like, which consists in heating a
refractory, independent, continuous conductor by including it within an electric
circuit, disconnecting it from the said electric circuit, and subjecting the material
associated with a suitable reducing agent, to the thermic effect of the said
electric conductor, whereby the said material is smelted, substantially as set forth.
4. A process for smelting ore, metal or the like, which consists in heating a
series of refractory electric conductors by the application of an electric current,
by subjecting said conductors to the effect of said current in sequence, and plac-
ing said conductors, after being so heated, successively in contact with the
material to be smelted, associated with a suitable reducing agent whereby said
material is smelted, at the same time other conductors of the said series are being
heated by the current, substantially as set forth.
5. An electric furnace consisting of a horizontal cylinder, composed of electric,
insulating, refractory material, electric conductors adapted to be heated to a
high degree of temperature, placed on the inner surface of the said cylinder, a
means for rotating the cylinder, and an electric circuit including a commutator
and the said electric conductors, substantially as set forth.
6. An electric furnace consisting of a horizontal cylinder composed of electric
insulating, refractory material, electric conductors, adapted to be heated to a high
degree of temperature, divided into groups on the inner surface of the said
cylinder, a means for rotating the cylinder, an electric circuit and a commutating
device for directing the current through the said groups of conductors in suc-
cession, substantially as set forth.
D
1011
1000
HERBERT HADDAN & Co.,
Agents to the Applicant,
18, Buckingham Street, Strand, London, W.C.