Improvements in the Manufacture or Production of Metallic Cyanides, particularly Cyanide of Potassium and of Sodium.
Year: 1895

page_text: Date of Application, 9th Dec., 1895
Complete Specification Left, 15th Jan., 1896-Accepted, 15th Feb., 1896
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture or Production of Metallic
Cyanides, particularly Cyanide of Potassium and of Sodium.
I, CARL KELLNER, of 29, Wasagasse, Vienna, 1X, Austria, Doctor of
Philosophy, do hereby declare the nature of this invention to be as follows:-
The methods, both indirect and direct, of producing metallic cyanides heretofore
known possess several serious disadvantages. Thus, for instance, when the said
cyanides are produced in an indirect way i.e. by the use of metallic ferro-cyanides
and the decomposition of the latter salts by alkaline carbonates at a high
temperature the raw molten product must, in order to obtain a commercial article,
be subsequently submitted to a thorough purification, which operation is very
expensive and takes a great deal of time.
When metallic cyanides are produced in a direct way, by fusing the oxides or
carbonates of the respective metals in the presence of carbonaceous substances rich
in nitrogen, or in the presence of carbonaceous substances and of a gas-mixture
rich in nitrogen, the appliances required for the execution of this process, even
when the fusing is effected by means of an electric current, are a great deal too
complicated for the execution of the process on an extensive manufacturing scale,
and the continuous introduction into the molten mass, at such high temperatures,
of air or generator gases rich in nitrogen, is always attended with considerable
inconveniences.
Now this invention has for its object a process by which the above mentioned
defects are entirely obviated. For this purpose the employment of carbonaceous
substances rich in nitrogen, or of gases rich in nitrogen, is entirely avoided during
the process of formation of metallic cyanides, the metallic salt or compound used
according to this invention, as the initial material for the production of the
corresponding cyanide, being such that it simultaneously serves also as a source of
nitrogen.
For practically carrying out my improved process, a nitrate or a nitrite of the
particular metal, the cyanide of which is to be produced, is fused in an electric arc.
During the fusing operation a chemical reaction takes place between the carbon
of the electrodes and the fused salt in such a manner that the salt is reduced,
its oxygen being replace during the reduction by carbon, so that the desired
cyanide is thereby produced.
Thus, for instance, for producing cyanide of potassium, saltpetre may be employed.
The reduction of the saltpetre by the aid of heat and carbon and the simultaneous
introduction of carbon into the resulting product, is effected by means of an electric
arc produced between carbon electrodes, the formation of a carbonate or carbonates
during this operation being thereby avoided.
The chemical reaction which takes place during this operation may be expressed
by the following formula :-
KNO, +4C - KCN +3 CO.
KNO, + 3 C = KCN + 2CO.
[Price 8d.]

page_text: For carrying out the above described process, it is preferable to use an electric
melting furnace which may be of known construction.
In order to promote the chemical action of the carbon of the anode upon the salt,
the nitrate or nitrite employed as the initial material can also be mixed with
carbon free from nitrogen and in this state submitted to the action of the
electrical arc.
When working with nitrates on a large scale, it will be advisable to melt the
nitrate in a separate vessel and mix the carbon therewith successively, so as to
promote the partial transformation of the nitrate into nitrite. This is however
not of great importance as regards the essential feature of the invention.
Dated this 9th day of December 1895.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
Improvements in the Manufacture or Production of Metallic
Cyanides, particularly Cyanide of Potassium and of Sodium.
I, CARL KELLNER, of 29, Wasagasse, Vienna, IX, Austria, Doctor of
Philosophy, 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 :—
The methods, both indirect and direct, of producing metallic cyanides heretofore
known, possess several serious disadvantages. Thus, for instance, when the said
cyanides are produced in an indirect way-i.e., by the use of metallic ferro-cyanides
and the decomposition of the latter salts by alkaline carbonates at a high temperature
-the raw molten product must, in order to obtain a commercial article, be
subsequently submitted to a thorough purification, which operation is very
expensive and takes a great deal of time. When metallic cyanides are produced
in a direct way, i.e., by fusing the oxides or carbonates of the respective metals
in the presence of carbonaceous substances rich in nitrogen, or in the presence
of carbonaceous substances and of a gas-mixture rich in nitrogen, the appliances
required for the execution of this process, even when the fusing is effected
by means of an electric current, are
a great deal too complicated for
the execution of the process on an extensive manufacturing scale, and the
continuous introduction into the molten mass, at such high temperatures, of air
or generator-gases rich in nitrogen, is always attended with considerable incon-
veniences.
Now this invention has for its object to provide a process by which the above
mentioned defects are entirely obviated. For this purpose the employment of
carbonaceous substances rich in nitrogen, or of gases rich in nitrogen, is entirely
avoided during the process of formation of metallic cyanides, the metallic salt
or compound used, according to this invention, as the initial material for the
production of the corresponding cyanide, being such that it simultaneously serves
also as a source of nitrogen.
For practically carrying out my improved process, a nitrate or a nitrite of the
particular metal, the cyanide of which is to be produced, is fused in an electric arc
produced between carbon electrodes. During the fusing operation, a chemical
reaction takes place between the carbon of the electrodes and the fused salt in such
a manner that the salt is reduced, its oxygen being replaced, during the reduction,
by carbon, so that the desired cyanide is thereby produced.
Thus, for instance, for producing cyanide of. potassium, saltpetre may be
employed. The reduction of the saltpetre by the aid of heat and carbon and the

page_text: simultaneous introduction of carbon into the resulting product is effected by means
of an electric are produced between carbon electrodes, the formation of a carbonate
or carbonates during this operation being thereby avoided.
The chemical reaction which takes place during this operation may be expressed
by the following formula :-
KNO, + 4 C
===
KCN +3 CO.
If instead of a nitrate, a nitrite should be employed, the reaction will take place
in an analogous manner and may be represented thus:-
KNO, + 3 C
= KCN + 2CO.
For carrying out the above described process, it is preferable to use an electric
melting furnace which may be of known construction.
In order to promote the chemical action of the carbon of the anode upon the
salt, the nitrate or nitrite employed as the initial material, can also be mixed with
carbon free from nitrogen and in this state submitted to the action of the
electrical arc.
When working with nitrates on a large scale, it will be advisable to melt the
nitrate in a separate vessel and to mix the carbon therewith in small quantities at a
time so as to promote the partial transformation of the nitrate into nitrite before.
subjecting it to the action of the electric are. This preliminary treatment by
carbon is, however, not of great importance as regards the essential feature of the
invention.
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 :-
:-
The manufacture or production of metallic cyanides, (cyanide of potassium,
cyanide of sodium and the like) by subjecting the nitrate or nitrite of the metal of
which a cyanide is required, either alone or mixed with carbon free from nitrogen,
to the action of an electric are formed between carbon electrodes as set forth.
1
T
1000
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.