An Improved Method of Heating or Fusing Refractory and other Substances.
Year: 1898

page_text: Date of Application, 24th Nov., 1898-Accepted, 21st Jan., 1899
COMPLETE SPECIFICATION.
An Improved Method of Heating or Fusing Refractory and other
Substances.
I, WILHELM BORCHERS, of 3, Lousberg Strasse, Aix-la-Chapelle, in the German
Empire, Professor of Metallurgy, 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, that is to say:-
This invention relates to an improved method of heating or fusing refractory and
other substances, and has reference more particularly to the employment of liquid
air or liquid oxygen for this purpose.
When high temperatures are to be produced with ordinary fuels, by burning
the latter in oxygen, or in gaseous mixtures rich in oxygen, it is, as has been
proved by experiments in producing calcium carbide without electricity, extremely
difficult to generate a flame which is uniformly hot and chemically inactive, and
even where this is achieved, it is still difficult to cause the heating gases to so act
upon the materials to be fused, as to cause the reaction to take place under the
desired conditions throughout the constituent parts of the mass.
Now, by my invention, I obviate these defects, as I will now proceed to describe
by way of example with reference to the manufacture of calcium carbide.
To this end, lime, calcium carbonate, or other suitable calcium compound, is
mixed as uniformly as possible with carbon, preferably in a pulverized form. To
this is added the necessary amount of a suitable fuel, for instance charcoal, coke,
coal, or the like, to produce the temperature required for reaction and fusion. The
whole is then placed in a crucible, muffle, or any other appropriate vessel. Either
prior, or subsequent, to this, however, I incorporate with the mass, liquid air or
liquid oxygen in quantity sufficient to ensure the combustion of the fuel, and in
such a manner that the charge is uniformly penetrated thereby.
It will depend upon the density of the materials employed, whether the liquid
air or oxygen be mixed with the charge, so as to form a wet mass, or whether the
charge be first rammed into the vessel, and the liquid air or oxygen be then added
so as to become uniformly absorbed by the charge.
The ignition of the mass is then effected by the aid of known chemical or electric
igniting devices (for instance fulminate of mercury, magnesium ribbon, electric
sparks, electrically heated or incandescent bodies and the like). According as the
effect of such igniting bodies or fuses is of a more or less violent character, the
combustion of the mass mixed with liquid air or liquid oxygen will take place more
or less rapidly.
When combustion takes place rapidly, a gas pressure will be developed so quickly
that the mass will fuse together at a moderate temperature in open vessels. As,
however, in such case, the fused product and the charge might easily be forced
out and scattered, I prefer to effect the combustion rather less abruptly, and in a
closed vessel, especially as the pressure thus generated can be released within any
desired limits, and even be utilized if so desired. This pressure has also a favour-
able effect upon the fusing mass, inasmuch as under an increased pressure the
temperature to be applied may be in most cases reduced.

page_text: By my invention, I obtain the following advantages over processes heretofore
employed:
1. Generation of high temperatures directly in the interior of the mass to be
fused:
2. Reduction of the necessary temperature for reaction and fusion, by means
of pressure developed in the interior of the charge:
3. Capability of utilizing the pressure of the gases produced by the reactions,
which gases being in most cases combustible (for instance carbonic oxide) and being
obtained without the objectionable presence of air, may be supplied to another
heating apparatus.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what
claim is:-
1. Heating substances by mixing them with fuel and with liquid air or liquid
oxygen, and then igniting the mixture in suitable vessels, substantially as and
for the purposes set forth.
2. Effecting the heating, as in the preceding claim, in closed vessels provided
with pressure regulating devices.
3. My improved method of heating or fusing refractory and other substances,
for the purpose of obtaining reactions between their constituents, substantially as
herein before described.
Dated this day of November 1898.
ERNEST DE PASS,
Chartered Patent Agent,
78, Fleet Street, London, and 5A, Market Street, Nottingham,
Agent for the Applicant.