Improved Metallic Carbides, applicable for Use in the Production of Acetylene, and Means for Producing the same.
Year: 1894

page_text: Date of Application, 1st Sept.. 1894
Complete Specification Left, 21th June, 1895-Accepted, 30th Nov., 1895
PROVISIONAL SPECIFICATION.
Improved Metallic Carbides, applicable for Use in the Production
of Acetylene, and Means for Producing the same.
I, THOMAS LEOPOLD WILLSON, of No. 19 West Thirty-eighth Street, in the
City of New York, United States of America, Electrical Engineer, do hereby
declare the nature of this invention to be as follows:-
I have discovered and produced a new commercial product being a compound of
calcium and carbon, namely, a calcium carbide. This new substance proves to
have important and valuable industrial uses.
The method of producing the new product referred to is as follows:-
1 take calcium oxide or lime (which may be anhydrous or slacked) and expose
it
with a deoxidizing reducing agent to the intense heat of an electric furnace for a
sufficient length of time. The furnace is an electric arc furnace. The intense
degree of heat that is only to be attained by converting electrical energy into heat
energy seems to be necessary to ensure the requisite reaction. The reducing
agents which I have employed are carbon and the heavier liquid or solid hydro-
carbons, but other reducing agents may be suitable.
As the carbide is taken from the furnace it cools and solidifies. It has a strong
afhmity for water, and if left exposed to the air gradually crumbles to powder. its
surface turning to a whitish gray by reason of the formation of lime by oxidation.
For this reason it is necessary to preserve the carbide by affording it a protective
covering, either by placing it in sealed vessels from which all moisture is excluded,
or beneath the surface of oil or by coating it with wax, or in some other manner to
protect it from moisture.
So great is the affinity of this substance for oxygen, that on dropping it into
cold water it rapidly decomposes the water, generating gas in large volume. The
residue of this reaction is milk of line, more or less discolored with graphite.
The generated gas is acetylene C,H,. On igniting the gas as it is evolved, and in
the open air, it burns with a yellowish and somewhat smoky flame, accompanied
with some precipitation of lamp black.
This new product which I have discovered will I believe develop important
practical uses in the arts. Its decomposition of water in the cold shows that it is a
powerful reducing or deoxidizing agent and points to probable uses as such agent
in metallurgical reductions and in various other chemical reactions, both wet and
diy. The great volume of gas evolved upon its combination with water points to
its utility as a disruptive or explosive agent under certain conditions. It has also
been demonstrated to produce a combustible or illuminating gas of great richness
and value. The strong affinity of this new substance for moisture opens up uses
for it as a dehydrating substance. It also proves valuable as a source from which
many chemical substances may be produced at less cost than by methods heretofore
in use.
The formula for the calcium carbide is believed to be CaC₂.
My invention may possibly be modified somewhat by the substitution of other
metallic compounds in place of calcium oxide. In my experiments I have found
that certain metallic oxides treated as I have described form metallic carbides,
while others apparently do not. Of the metallic carbides so formed some are
capable of mutual decomposition with water, while others are not so capable.
For

page_text: example aluminium oxide so treated is largely reduced to aluminium carbide, but
this exhibits no reaction with water, and hence would not be included within my
present invention. From such experimental and other data as I have been able to
collect I am led to believe that my invention may be applied in making carbides of
any of the group of metals which exist in the native state as carbonates, namely,
calcium, magnesium, barium, strontium, zircon (rare) and perhaps also lithium
(rare).
I believe my invention to include any metallic carbide capable of a mutual
reaction with water, no such carbide having been known or commercially available
prior to my invention or discovery.
Dated this 1st day of September 1894.
J. C. MEWBURN & ELLIS,
55 and 56 Chancery Lane, London, Patent Agents.
Improved Metallic Carbides, applicable for Use in the Production
of Acetylene, and Means for Producing the same.
I, THOMAS LEOPOLD WILI SON formerly of Number 19, West Thirty-eighth
Street in the City of New York, United States of America, but now of Plaza
Hotel, New York aforesaid, Electrical Engineer, do hereby declare the nature of
the said 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 the production of metallic carbides suitable for the
production of acetylene gas which may be used for illuminating, heating and other
purposes.
By the use of calcium carbide produced according to my invention acetylene gas
may be generated in large quantities and at very moderate cost, such as opens up
commercial uses for such gas which have hitherto been impracticable because of
the great rost of its production. According to my new process I treat calcium
oxide or some other suitable compound containing calcium such for example as
dolomite in the presence of carbonaceous matter, such as carbon, or hydrocarbon,
by exposure to the intense heat of an electric are in an electric furnace, whereby
the oxygen is withdrawn from the calcium and its place taken by carbon, forming
a calcium carbide. and by using water to re-act with this calcium carbide, mutual
decomposition may be brought about wherein the hydrogen of the water unites
with the carbon of the carbide to form dihydrogen dicarbide or acetylene, which
escapes as gas. By this process the gas can be produced with great economy.
In carrying out my invention I employ a suitable electric furnace, such as a
Siemens are furnace and in its chamber I place lime and carbonaceous matter, and
pass a powerful electric current though it in order to generate an enormous degree
of heat. The lime may be quicklime in lumps or powder, and be mechanically
mixed with carbon in the form of coal, or by slacking or hydrating the lime it
may be more intimately combined with carbonaceous matter by stirring it into a
quid hydrocarbon, preferably coal tar pitch kept liquid by heat; when the
hydiocarbon has taken up all of the lime that it will, the mixture is dried by heat
and placed in the furnace. Or the lime and carbonaceous matter may be charged
into the furnace from time to me, or in alternation, during the operation. Or
instead of introducing separate carbonaceous matter, the heavy carbon peucils or
slabs of the furnace may be relied upon as the source of carbon, although this
is disadvantageous because less economical than to provide carbon in the other
forms named. In practice I mix together powdered lime and powdered coke or
coal in the proportions of approximately 90 pounds of lime to 60 pounds of carbon,

page_text: using a furnace with a carbon hearth or crucible and an upright carbon pencil
connected to opposite terminals of a suitably proportioned dynamo electric
generator. The pencil is pressed against the hearth and the mixed materials fed
in around it, the current being then established the pencil is lifted to draw an arc
which heats the materials and effects the reduction. The treatment in the furnace
deoxidises the lime, the oxygen escaping as carbon-monoxide or carbon dioxide
gas, and the calcium thus set free enters into a new combination with the carbon
forming a calcium carbide, the formula for which is believed to be CaC. This
material may be tapped out of the furnace at a white heat or may be removed at the
close of the operation. As the carbide is taken from the furnace it cools and
solidifies in crystalline masses. Since making the invention which is the subject
of this Patent I have discovered that great advantages arise by using an alternating
instead of a continuous current. It is intended to make this the subject of a fresh
application for a Patent and I therefore make no claim for it in this Specification.
The affinity of the carbide for water is so strong that if left exposed to the air it
gradually crumbles to powder, its surface turning to a whitish grey by the
formation of lime. It is consequently necessary if the material is to be preserved
for some time, to enclose it in vessels from which all moisture is excluded or to
keep it beneath the surface of oil, or otherwise to protect it from moisture.
In using this calcium carbide for the manufacture of acetylene I take a bath of
water and drop the calcium carbide into it in suitable quantities from time to time,.
catching the generated gas by any suitable closed vessel and conducting it to any
suitable gasometer or gasholder. Upon dropping the calcium carbide into the water a
violent decomposition takes place accompanied by the evolution of large quantities
of acetylene gas, and leaving a residue of hydrated calcium oxide, the reaction
being believed to be CaC, + (H₂O), H,C,+ Ca(HO),. Approximately
5.8 cubic feet of acetylene produced per pound of calcium carbide the proportion
varying according to the purity of the carbide, which is liable to contain carbon
or graphite and sometimes lime as impurities.
=
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:-
1. The manufacture of crystalline calcium carbide by subjecting lime and
carbonaceous matter in suitable proportions to the continued action of electrically
generated heat, substantially as hereinbefore described.
2. The process of producing crystalline calcium carbide, consisting in subjecting
lime and carbonaceous matter in suitable proportions to the continued heat of an
electric arc between a carbon pencil above and a conducting hearth, or pool of
reduced material thereon, beneath, substantially as hereinbefore described.
3. The process of treating a compound containing calcium with carbonaceous
matter in an electric furnace as hereinbefore described to produce a carbide of the
metal, or metals contained in such compound and afterwards acting upon the carbide
so formed with water to generate a hydrocarbon gas, substantially as herein before
described.
4. The process of treating calcium oxide with carbonaceous material in an
electric furnace as herein before described to produce calcium carbide, and after-
wards acting upon the calcium carbide with water to liberate acetylene substantially
as described.
Doted thin 97th
J. C. MEWBURN & ELLIS,
55 and 56 Chancery Lane, London, Chartered Patent Agents.