Improvements in the Process of Making Calcium Carbide.
Year: 1898

page_text: [Communicated from abroad by JAMES ELLICOTT HEWES, of 421, Chestnut Street,
Philadelphia, Pennsylvania, U.S.A., Electrical and Mechanical Engineer.]
Improvements in the Process of Making Calcium Carbide.
I, GEORGE BOWER, St. Neots Hunts., Engineer, do hereby declare the nature
of this invention to be as follows:-
com-
Objects of my invention are to facilitate the combination of carbon and calcium
with
and
chemical
the expenditure of
combination
thus effect
paratively little heat energy; to effect the chemical combination of these materials
without necessarily reducing the lime to such a finely powdered condition as has
been hitherto deemed requisite; to effect the chemical combination while main-
taining the mass in the furnace in a molten state, whereby the nascent calcium
is brought into intimate contact with carbon particles, so that it cannot escape
and must combine with the carbon, which need not be present in excess; to
minimize loss of carbon and calcium and mechanical losses due to the driving
action of an arc which throws the materials out of the furnace, and to increase
the output and improve the quality of the finished product.
In my invention use is made of a flux or admixture that is placed in the elec-
tric furnace along with the carbide producing materials, which contain calcium
and carbon, and calcium-carbide compounds or double-carbides are produced.
By reason of the presence of this flux the chemical action is caused to take place
in a more congenial medium than heretofore and the reaction is thus promoted.
Nascent calcium is brought into intimate contact with carbon and is constrained
Thus the
to combine therewith by reason of the presence of the fused mass.
escape of volatilized calcium is prevented and the presence of an excess of carbon
rendered unnecessary, whereby honeycombing of the product is prevented and
the output of the furnace increased. Since the mass is in a fused state, it
follows that a fine state of subdivision of the lime is not essential. The tux
is employed in a proportion of from five to ten per cent. more or less, and it
consists of oxide of manganese (for example, manganic oxide, which forms with
the carbon, carbide of manganese,) and of carbonate of calcium, which reduces
to nascent calcium and combines with carbon to make carbide of calcium.
The proportions of the ingredients in the complete charge will vary with the
quality of the lime and carbon employed and may be stated as follows: carbon,
twenty-six parts by weight; calcium oxide, sixty-four parts by weight; calcium
carbonate, eight parts by weight; and manganese oxide two parts by weight.
I may, however mention as proportions of the flux itself one part manganese
dioxide to nine parts calcium carbonate. The flux may be made into briquets,
pastils, or cakes, with or without either additional carbon and lime, or both
by means of molds and pressure and a carbonaceous binder, or it may be
otherwise introduced into the mass. Under the influence of the arc the flux and
mass adjacent to the are melt. Then chemical combination takes place in this

page_text: molten mass, manganese and carbon forming manganese carbide and carbon
and calcium forming calcium carbide, and the calcium carbonate is reduced to
calcium oxide, then to calcium, which latter unites with carbon to form calcium
carbides. The calcium carbonate is melted and the carbon dioxide bubbles off.
The current during this operation may be approximately two thousand four hun-
dred amperes at seventy volts in a furnace approximately four feet long, four
feet wide, and three feet high.
The described flux is basic in its reaction and has the property of eliminating
phosphorus and sulphur, which are deleterious, dangerous, and omnipresent in
ordinary commercial carbide. Some of the flux or admixture combines with
phosphorus and sulphur, which was present in the commercial coke, and there
are formed phosphides and sulphides, as of calcium, which remain as a crust
or slag on top of the mass of the carbide.
Probably the described bubbling of dioxide, or at any rate, the action
resulting from the admixture of calcium carbonate, causes the phosphides and
sulphides to rise and thus form the top crust or slag, which is removed or broken
from the finished product, as will be hereinafter explained. The gas given off in cases
where lime and carbon, without carbonate of lime, are used does not operate to bring
the impurities to the top, as described. In coke phosphorus is usually present as
phosphoric acid and sulphur as such. This crust or slag is broken off and
removed from the finished carbide. After the formation of carbide is well
started the electrode is moved into the mass and interrupts the arc.
The cur-
rent then flows through the molten mass and is maintained constant and con-
tinuous, in contradistinction to alternating. This constant continuous current of
two thousand four hundred amperes and fifty to sixty volts results in the
production of the carbide concentrically, so that the previously formed carbide
grows in cross section and the adjoining wall of unfused mixture is gradually
converted into calcium carbide compound or double carbide-that is, carbide
of calcium and carbide of manganese. By the use of a continuous current at
the described stage of the process the voltage may be greatly reduced, as described,
and thus a saving is effected.
The oxide of manganese, or dioxide as it has been called, melts at a lower tem-
perature than the lime, and thus forms a medium in which the chemical cum-
bination can occur, as described. Moreover, the manganese oxide is converted
into manganese_carbide.
I am aware that manganese has been used for the production of methane and
hydrogen to enable acetylene gas to be more perfectly consumed, but my use of
it is for an altogether different purpose, namely for ue as a flux.
The electric furnace best adapted for carrying out the above process and its
method of operating is hereinafter described, which method and process I also
desire to claim.
The nature, characteristic features and scope of my invention will be more
fully understood from the following description taken in connection in connection
with the accompanying drawings forming part hereof and in which
Figure 1 is a view partly in section of a furnace embodying features of my
invention and adapted for carrying my process into effect.
Figure 2 is a top or plan view of the same.
Figure 3 is a sectional view taken on the line 3-3 of Fig. 1.
In the drawings, a is the masonry or other base of a horizontal electric furnace.
Upon the base a is mounted a plate b which constitutes a terminal. The elec-
trode c is afforded a range of horizontal motion by means, for example, of the
wheel d and screw and hand wheel e. The source of electricity and electrical
connections are designated by the reference letters f, g, and g¹. h is a remov-
able hopper that may be provided with eyes as to which hooks or cords may
be attached for the purpose of lifting it bodily from the furnace bed or founda-
tion a.
This hopper is provided with an electrode that rests upon and makes
contact with the plate or terminal b. It is also provided with suitable side

page_text: walls. Opposite to the electrode i may be a wall or abutment j. Mounted in
the electrode c are a number of pencils or carbons of which those designated k
are longer than those designated or at any rate the pencils k protrude further
than the others. The number of carbons in each set is not important and may
be varied. As shewn in the drawings, there are four long or protruding pencils k
and twelve short pencils Provision is made for controlling the electrical
conditions of the circuit.
Coke or refuse calcium carbide in limited quantity as shewn at A is placed
in the hopper in order to protect the plate forming the electrode i and the pen-
cils are brought into contact with the electrode i, thus completing the cir-
cuit f, g, b, i, k, c, g¹. Carbon, ground so as to pass, for example, through a
forty mesh, is inserted into the hopper until it is one third full, more or less.
This underlying layer of carbon is designated 7. A mixture m containing
carbon and calcium generally in the form of lime is then put on top of the layer
of carbon, and a top layer of broken coke or bricks, stones and the like as n,
about a foot thick is placed upon the mixture of carbide producing materials m.
The arc is now shifted in the mixture m by moving the electrode c toward the right,
or in other words, away from the electrode and maintaining a current of, for
example, a thousand amperes at the pencils or carbons k, which may be sixty-four
inches in cross section. This are gives rise to the rapid production of a thin shaft or
"teazer" of incomplete calcium carbide, it being understood that the electrodes
are gradually separated during its formation. Upon the completion of a shaft
or teazer of the required length the pencils or carbons are forced back (that is
toward the left in the drawings) into the mass of carbide and unfinished mixture.
The current now flows from the faces of all the pencils and tends to increase
in amperage. However, I restrain such tendency in any appropriate manner,
for example, by the insertion of induction or the proper manipulation of the
exciting current of the dynamo to about five thousand amperes.
The carbide shaft or "teazer" is a good conductor and remains incandescent,
thus causing the particles of the carbide producing mixture m, which lie in
a zone surrounding it to be chemically combined so that the mass of calcium
carbide does not increase in length but does increase or grow in diameter. Since
the teazer or shaft is a good conductor and since it is made to carry an excessive
current it follows that the current flowing through it keeps it hot. During
these operations the top layer or coke n permits the gases generated at and near
the arc to escape through it, but it retains the carbide producing material and
prevents it from becoming thrown out at the top so that as a saving is effected.
Moreover, the furnace being properly charged, no further stoking is necessary
because the mass of carbide of calcium increases in diameter as has been explained
and this absence of stoking is obviously a desirable feature. Since the carbon
pencils k, are completely embedded at all times they are not exposed to the
air, and therefore are not consumed or burned and last a comparatively long
time. The carbon strewn upon the floor of the furnace and constituting the
layer is of course brought into contact with the diametrically growing mass
of calcium carbide, and the latter absorbs this carbon chemically, not necessarily
crystalline like normal carbide. Upon the completion of the treatment of the
material contained in one hopper, it may be removed and replaced by another
hopper and the finished product may be dumped from its containing hopper.
It will be obvious to those skilled in the art to which my invention appertains
that modifications may be made without departing from the spirit thereof, hence
I do not limit myself to the precise construction and arrangement hereinabove
set forth and illustrated in the accompanying drawings.
Out ..
1000

page_text: I, GEORGE BOWER, St. Neots Hunts., Engineer, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:-
Objects of my invention are to facilitate the combination of carbon and calcium
and thus effect chemical combination with the expenditure of com-
paratively little heat energy; to effect the chemical combination of these materials
without necessarily reducing the lime to such a finely powdered condition as has
hitherto been deemed requisite; to effect the chemical combination while main-
taining the mass in the furnace in a molten state, whereby the nascent calcium
is brought into intimate contact with carbon particles, so that it cannot escape
and must combine with the carbon, which need not be present in excess; to
minimize loss of carbon and calcium and mechanical losses due to the driving
action of an arc which throws the materials out of the furnace, and to increase
the output and improve the quality of the finished product.
In my invention use is made of a flux or admixture that is placed in the elec-
tric furnace along with the carbide producing materials, which contain calcium
and carbon, and calcium-carbide compounds or double carbides are produced.
By reason of the presence of this flux the chemical action is caused to take place
in a more congenial medium than heretofore and the reaction is thus promoted.
Nascent calcium is brought into intimate contact with carbon and is constrained
to combine therewith by reason of the presence of the fused mass. Thus the
escape of volatilized calcium is prevented and the presence of an excess of carbon
rendered unnecessary, whereby honeycombing of the product is prevented and
the output of the furnace increased. Since the mass is in a fused state, it
follows that a fine state of subdivision of the lime is not essential. The flux
is employed in a proportion of from 5 to ten per cent. more or less, and it
consists of oxide of manganese, for example manganic oxide, which forms with
the carbon carbide of manganese, and of carbonate of calcium, which reduces
to nascent calcium and combines with carbon to make carbide of calcium.
The proportions of the ingredients in the complete charge will vary with the
quality of the lime and carbon employed and may be stated as follows: carbon,
twenty-six parts by weight; calcium oxide, sixty-four parts by weight: calcium
carbonate, eight parts by weight; and manganese oxide two parts by weight.
I may however mention as proportions of the flux itself one part manganese
dioxide to nine parts calcium carbonate. The flux may be made into briquets,
pastils, or cakes, with or without either additional carbon and lime, or both
by means of moulds and pressure and a carbonaceous binder, or it may other-
wise be introduced into the mass. Under the influence of the are the flux and
mass adjacent to the arc, melt. Then chemical combination takes place in this
molten mass, manganese and carbon forming manganese carbide and carbon
and calcium forming calcium carbide, and the calcium carbonate is reduced to
calcium oxide, then to calcium, which latter unites with carbon to form calcium
carbides. The calcium carbonate is melted and the carbon dioxide bubbles off.
The current during this operation may be approximately two thousand four hun-
dred amperes at seventy volts in a furnace approximately four feet long, four
feet wide, and three feet high.
The described flux is basic in its reaction and has the property of eliminating
phosphorus and sulphur, which are deleterious, dangerous and omnipresent in
ordinary commercial carbide. Some of the flux or admixture combines with

page_text: phosphorus and sulphur, which was present in the commercial coke, and there
are formed phosphates and sulphides, as of calcium, which remain as a crust
or slag on top of the mass of the carbide.
Probably the described bubbling of carbon dioxide, or at any rate, the action
resulting from the admixture of calcium carbonate, causes the phosphates and
sulphides to rise and thus form the top crust or slag, which is removed or broken
from the finished product, in any convenient manner. The gas given off in cases
where lime and carbon, without carbonate of lime, are used does not operate to
bring the impurities to the top, as described. In coke phosphorus is usually present
as phosphoric acid and sulphur as such. This crust or slag is broken off and
removed from the finished carbide. After the formation of carbide is well
started the electrode is moved into the mass and interrupts the arc.
The cur-
rent then flows through the molten mass and is maintained constant and con-
tinuous, in contradistinction to alternating. This constant continuous current of
approximately two thousand four hundred amperes and seventy volts results in the
production of the carbide concentrically, so that the previously formed carbide
grows in cross section and the adjoining wall of unfused mixture is gradually
converted into calcium carbide compound or double carbide-that is, carbide
of calcium and carbide of manganese. By the use of a continuous current at
the described stage of the process the voltage may be reduced, if desired and
thus a saving is effected.
The oxide of manganese, or dioxide as it has been called, melts at a lower tem-
perature than the lime, and thus forms a medium in which the chemical com-
bination can occur, as described. Moreover, the manganese oxide is converted
into manganese carbide.
I am aware that manganese has been used for the production of methane and
hydrogen to enable acetylene gas to be more perfectly consumed, but my use of
it is for an altogether different purpose, namely for use as a flux.
The electric furnace best adapted for carrying out the above process and its
method of operating is hereinafter described, which method and process I also
desire to claim.
The nature, characteristic features and scope of my invention will be more
fully understood from the following description taken in connection with the
drawings filed with my Provisional Specification and in which
Figure 1 is a view partly in section of a furnace embodying features of my
invention and adapted for carrying my process into effect.
Figure 2 is a top or plan view of the same.
Figure 3 is a sectional view taken on the line 3-3 of Figure 1.
In the drawings, a is the masonry or other base of a horizontal electric furnace.
Upon the base a is mounted a plate which constitutes a terminal. The elec-
trode c is afforded a range of horizontal motion by means for example of the
wheel d and screw and hand wheel e. The source of electricity and electrical
connections are designated by the reference letters f, g, and g¹. h is a remov-
able hopper that may be provided with eyes as h¹ to which hooks or cords may
be attached for the purpose of lifting it bodily from the furnace bed or founda-
tion a.
This hopper is provided with an electrode that rests upon and makes
contact with the plate or terminal b. It is also provided with suitable side
walls. Opposite to the electrode i may be a wall or abutment j. Mounted in
the electrode c are a number of pencils or carbons of which those designated k
are longer than those designated or at any rate the pencils & protrude further
than the others. The number of carbons in each set is not important and may
be varied. As shewn in the drawings, there are four long or protruding pencils k
and twelve short pencils. Provision is made for controlling the electrical
conditions of the circuit, that is to say the current may be converted from an
alternating to a continuous one as required by any suitable form of apparatus
as may be well known & convenient.

page_text: ""
<
Coke or refuse calcium carbide in limited quantity as shewn at A is placed
in the hopper in order to protect the plate forming the electrode i and the pen-
cils are brought into contact with the electrode i, thus completing the cir-
cuit f, g, b, i, k, c, gl. Carbon, ground so as to pass, for example, through a
forty mesh, is inserted into the hopper until it is one third full, more or less.
This underlying layer of carbon is designated !. A mixture m containing
carbon and calcium generally in the form of lime is then put on top of the layer
of carbon, and a top layer of broken coke or bricks, stones and the like as ",
about a foot thick is placed upon the mixture of carbide producing materials m
with a flux as previously mentioned. The arc is now shifted in the
mixture m by moving the electrode e toward the right, or in other words, away
from the electrode and maintaining a current of, for example, two thousand
four hundred amperes at the pencils or carbonsk, which may be sixty-four inches
in cross section. This are gives rise to the rapid production of a thin shaft or
teazer of incomplete calcium carbide, it being understood that the electrodes
are gradually separated during its formation. Upon the completion of a shaft
or teazer of the required length the pencils or carbons are forced back (that is
toward the left in the drawings) into the mass of carbide and unfinished mixture.
The current now flows from the faces of all the pencils and may tend to increase
in amperage. However, I restrain such tendency in any appropriate manner,
for example, by the insertion of induction or the proper manipulation of the
exciting current of the dynamo to about two thousand four hundred amperes.
The carbide shaft or teazer" is a good conductor and remains incandescent,
thus causing the particles of the carbide producing mixture m, which lie in
a zone surrounding it to be chemically combined, so that the mass of calcium
carbide does not increase in length but does increase or grow in diameter. Since
the teazer or shaft is a good conductor and since it is made to carry an excessive
current it follows that the current flowing through it keeps it hot. During
these operations the top layer or coke n permits the gases generated at and near
the arc to escape through it, but it retains the carbide producing material and
prevents it from becoming thrown out at the top so that a saving is effected.
Moreover, the furnace being properly charged, no further stoking is necessary
because the mass of carbide of calcium increases in diameter as has been explained
and this absence of stoking is obviously a desirable feature. Since the carbon
pencils, are completely embedded at all times they are not exposed to the
air, and therefore are not consumed or burned and last a comparatively long
time. The carbon strewn upon the floor of the furnace and constituting the
layer is of course brought into contact with the diametrically growing mass
of calcium carbide, and the latter absorbs this carbon chemically, not necessarily
crystalline like normal carbide. Upon the completion of the treatment of the
material contained in one hopper, it may be removed and replaced by another
hopper and the finished product may be dumped from its containing hopper.
It will be obvious to those skilled in the art to which my invention appertains
that modifications may be made without departing from the spirit thereof, hence
I do not limit myself to the precise construction and arrangement hereinabove
set forth and illustrated in the accompanying drawings.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what
I clain is:-
1. The hereindescribed process and apparatus for the production of calcium
carbide as described and illustrated herein and for the purpose set forth.
2. The herein described process which consists in subjecting a mixture of
carbide of calcium producing material substantially as described, and a flux
consisting of manganese oxide and calcium carbonate to the action of heat,
substantially as specified.
3. The herein described process which consists in mixing carbide producing

page_text: materials, substantially as described, and a flux containing manganese, and then
subjecting the mass to the action of heat, substantially as specified.
4. As an improvement in the art of manufacturing carbide the herein described
process which consists in introducing carbon and lime into a fused bath con-
taining manganese and calcium and oxygen and passing a continuous electric
current through the fused mass to effect chemical combination, substantially
as described.
5. The herein described process which consists in forming a core or conducting
path of calcium carbide and molten lime ready to take up carbon in the presence
of free carbon by means of a current of electricity passing between clectrodes,
and then increasing the working cross section of one of said electrodes and
maintaining said core or conducting path incandescent by a current to cause it
to take up carbon and to form carbide concentrically around it, substantially
as described.
6. The herein described process which consists in forming a core or conduct-
ing path of calcium carbide and molten lime ready to take up carbon in the
presence of free pulverulent carbon by means of a current of electricity passing
between electrodes, and then maintaining said core or conducting path incan-
descent by a current to cause it to take up carbon and to form carbide concen-
trically around it, substantially as described.
7. In combination an electric furnace having a plate-like electrode, pencils or
carbons of which some protrude beyond the others and all of which make up
the second electrode, means for shifting one of said electrodes to close circuit
through the protruding pencils and subsequently through all the pencils, and
circuit connections and their controlling devices, substantially as described.
8. In combination a furnace having its terminal plate as b, connected in cir-
cuit, a detachable hopper having one of its conducting walls adapted to rest on
and form electrical contact with said plate, a horizontally adjustable electrode
having circuit connections, and means for shifting the last mentioned, electrode,
substantially as described.
:
9. In apparatus for the production of calcium carbide the combined construc-
tion and arrangement of the various parts substantially as described and illus-
trated herein and for the purpose set forth.
Datel this 28th day of Donamba 1908