Improvements in the Production of Metallic Carbides and of Illuminating Gas derived therefrom.
Year: 1894

page_text: Date of Application, 27th Aug., 1891
Complete Specification Left, 27th. June, 1895-Accepted, 27th Nov., 1895
PROVISIONAL SPECIFICATION.
Improvements in the Production of Metallic Carbides and of
Illuminating Gas derived therefrom.
A communication from abroad by THOMAS LEOPOLD WILLSON, of New York,
United States of America, Electrical Engineer.
1, GEORGE BELOE ELLIS of the Firm of J. C. Mewburn and Ellis Patent
Agents of 55 and 56 Chancery Lane, London, do hereby declare the nature of this
invention to be as follows:-
This invention relates to the production of metallic carbides and chiefly consists
in submitting a metal of the alkaline earths or its oxides and carbon to the action
of the electric arc.
Another part of this invention consists in the production of acetylene which can
be used for the purpose of illuminating gas.
In carrying out the first part of my invention ! heat by way of example lime
and carbon in an electric furnace; thereby producing calcium carbide. This has
an active affinity for water evolving acetylene and leaving calcium hydroxide. The
acetylene can be collected in suitable vessels and used for the purposes hereafter
mentioned.
The carbide has various useful applications and can be used as a deoxydizing,
disrupting or dehydrating agent.
Dated this 27th day of August 1894.
J. C. MEWBURN & ELLIS,
55 and 56 Chancery Lane, London, Patent Agents.
Improvements in the Production of Metallic Carbides and of
Illuminating Gas derived therefrom.
A communication from abroad by THOMAS LEOPOLD WILLSON, of New York,
United States of America, Electrical Engineer.
I, GEORGE BELOE ELLIS of the Firm of J. C. Mewburn and Ellis, Patent
Agents of 55 and 56 Chancery Lane, London, 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 :-
According to this invention calcium oxide or lime or some other suitable
compound containing calcium such for example as dolomite is treated in the
presence of carbonaceous matter by exposure to the intense heat of the electric
arc in an electric furnace for a sufficient length of time. The intense degree of
beat that is only to be attained by converting electrical energy into heat energy
seems to be necessary to ensure the requisite reaction. Carbon and the heavier
liquid or solid hydrocarbons may be used; but carbon in the form of pulverised coal
or coke is preferable. In practice, pulverulent lime and coke or coal are mixed in
1 Paine Q71

page_text: the proportions of approximately 90 pounds of lime to 60 pounds of carbon.
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 calcium carbide as it is formed fusing
and forming a pool on the hearth, on which pool the mixture which is again fed
into the furnace floats. As the pool or bath of carbide accumulates, the carbon
pencil is raised to maintain the arc, which is drawn between the electro-conductive
carbide as one electrode and the carbon pencil as the other. The molten carbide
may be tapped off from time to time. Since making the invention which is the
subject of this Patent my correspondant has 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 therefore no claim is made
for it in this Specification.
As the carbide is taken from the furnace it couls and solidifies in crystalline
masses. It has a strong affinity for water, and if left exposed to the air gradually
crumbles to powder, its surface turning to a whitish grey by reason of the formation
of lime.
So great is the affinity of this carbide for water, that on bringing it into contact
with cold water, it rapidly decomposes the water, generating gas in large volume.
The residue of this reaction is milk of lime, sometimes slightly discoloured with
graphite. The generated gas is acetylene C₂H.. 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.
The product of this invention is distinguished from calcium carbide previously
produced in minute quantities for laboratory experiments, in that it is crystalline,
existing in masses of aggregated crystals, whereas the previous carbide was
amorphous, and incapable of being aggregated into a solid mass or lump. It is also
distinguished by its almost complete purity, and evolves a volume of acetylene
gas when treated with water, amounting to approximately 58 cubic feet (at
atmospheric pressure) per pound of carbide.
This new product, crystalline calcium carbide, which my correspondent has
discovered, will it is believed, develop important practical uses in the arts.
Its
decomposition of water in the cold shows that it is an agent having powerful
affinities, and points to probable uses as a reducing agent in metallurgical reductions
and in various other chemical reactions, both wet and dry.
The strong affinity of calcium canbide for moisture opens up uses for it as a
dehydrating substance. In dehydrating it acts by decomposing the water present
and evolves acetylene gas, hence its use is limited to the dehydration of such
substances as are not impaired by the presence of this gas notably for dehydration
of combustible or illuminating gases, which by the operation of dehydration are
enriched by the addition of the highly illuminating acetylene. If acetylene gas
generated from calcium carbide and water (and which commonly carries off moisture
in suspension) is passed into contact with calcium carbide, it is dehydrated and its
volume is increased by the addition to it of the newly generated gas.
The formula for calcium carbide is believed to be CaC₂.
Having now particularly described and ascertained the nature of the said joven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. The process of producing crystalline calcium carbide, consisting in subjecting
lime and carbonaceous matter in suitable proportions to the continued heat of an
electric are between a carbon pencil above and a conducting hearth, or pool of
reduced material thereon, beneath, substantially as herein before described.
2. The process of producing hydrocarbon gas by heating a compound containing
calcium with carbonacous matter in an electric furnace as hereinbefore described to

page_text: produce a carbide of the metal or metals contained in such compound and
afterwards by acting upon the carbide so formed with water to generate the
hydrocarbon gas substantially as hereinbefore described.
3. The process of producing acetylene gas which consists in treating calcium
oxide with carbonaceous matter in an electric furnace as hereinbefore described
to produce calcium carbide and afterwards acting upon the calcium carbide with
water to produce acetylene, substantially as hereinbefore described.
Dated this 27th day of June 1895.
J. C. MEWBURN & ELLIS,
55 and 56 Chancery Lane, London, Chartered Patent Agents.