An Improved Method of Producing Carbides.
Year: 1898

page_text: Date of Application, 17th Feb., 1898-Accepted, 7th May, 1898
CUMPLEIE DIFOLIATION
An Improved Method of Producing Carbides.
I, JOHN LANDIN, of 40, Drottninggatan, Stockholm, Kingdom of Sweden,
Engineer, 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:
-
In the production of carbides as carbides of calcium, silicium and the like, the
methods heretofore employed have been characterized by the mixing of the
pulverized raw materials and the heating of the mixture in its pulverized state
in an electric furnace.
My invention on the other hand, relates to the transforming of the raw materials,
previous to their heating for the formation of carbide and with or without the
addition of substances which serve to improve their fusibility and conductivity
and to facilitate the process, into a uniform mass, for instance into briquettes,
rods etc. This mass subsequently is introduced between carbon electrodes,
preferably on being previously heated, the carbide now forming with readiness and
completeness. Besides gaining the advantage of obtaining a charging mixture of
greater homogeneity, which gives the different substances a better opportunity to
react on one another, the disadvantage is avoided which is connected with the
treatment of the materials in a pulverized state, viz.; that the gases developed
during the formation of the carbide scatter the powder about and cause disturbances
in the proportions of the mixture, thus materially reducing the quantity of carbide
produced.
In order to obtain the charge in the solid, homogenous form, above mentioned,
the following method is adopted.
The pulverized raw materials are well mixed in their pulverized state with tar
or other material containing hydrocarbon and the mass is subsequently pressed
into briquettes, rods or the like, which are then heated, preferably under pressure,
to 300° or 500° C., the mass thereby changing its aggregate state and forming a
solid, uniformly caked mass. In producing carbide of calcium, oxide or carbonate
of lime (60 parts by weight of lime or 105 parts by weight of limestone) and 40
parts by weight of carbon are thus mixed with 5-10% tar or other material con-
taining hydrocarbon and the mass thus obtained is then treated as before
mentioned.
The latter is now introduced or mechanically pressed between carbon electrodes
in an electric furnace for the formation of carbide, the mass preferably having
being previously highly heated during which operation the carbonic oxide gas
generated in the formation of the carbide can be utilized to advantage. Pressing
the mass in between the electrodes can be accomplished by forcing it through a
hollow cylinder which may constitute one of the carbon electrodes. In order to
make the wear of the electrodes more even and avoid inconvenience owing to the
formation of slag between them, the electrodes may be made movable about their
longitudinal directions besides being made adjustable in a known manner as
regards their distance from each other. In order to favour the formation of
carbide still further, there may be added to the raw materials, such fluxes as

page_text: contain the substance the carbide of which is to be produced, for instance, in the
case of producing carbide of calcium, chloride of calcium. The latter is suitably
introduced in the mass previous to its transformation into the solid, uniform state.
When the electric furnace is charged with this mass the chloride of calcium
disassociates into calcium, which in its nascent state readily combines with
carbon into carbide, and chlorine which in the colder portions of the mass reacts
on lime, causing chloride of calcium to be reformed, and so on.
When a direct current is used for forming the electric arc, the molten chloride
of calcium is also decomposed,, purely, electrolytically, the calcium and chlorine
formed reacting as above mentioned. In this case also the carbonaceous material
to be combined with calcium can constitute one of the electrodes. By adding to
the charge other metallic oxides besides that of calcium, said oxides being intro-
duced in the manner stated regarding the chloride of calcium, for instance a few
per cent. of oxide of barium or magnesium, the mass of carbide is fused more
easily, this having proved to be a matter of importance more particularly, when
using peat or peat-coal as the carbonaceous raw material. The conductivity of
the mass may be improved, by the addition of graphite or the like.
The production of other carbides is accomplished in analogous manner.
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:
·
An improved method of producing carbides, consisting in the mixing together
of the pulverized raw materials (oxide or carbonate of lime and carbon in the
case of making carbide of calcium, silicic acid and carbon in the case of making
carbide of silicium and the like) while adding tar, or other material containing
hydrocarbon, and alternatively as fluxes combinations of the substance the carbide
of which is to be produced for instance in the case of carbide of calcium, chloride
of calcium, and the subsequent pressing and heating of the mixture until it
changes its aggregate state so as to form a uniform mass in which state it is intro-
duced, with or without being previously highly heated, between the carbon
electrodes of an electric furnace, the electrodes of which may be made movable
about their longitudinal directions, to avoid the inconvenience arising in the case
of their slagging together with the bloom formed.
Doted this 17th dor of Wahmo 1900
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.