Improvements relating to the Manufacture of Oyanides and to Apparatus therefor.
Year: 1894

page_text: Date of Application, 29th Sept., 1894
Complete Specification Left, 28th June, 1895-Accepted, 3rd Aug., 1895
PROVISIONAL SPECIFICATION:
Improvements relating to the Manufacture of Oyanides and to
Apparatus therefor.
I, JOHANNES PFLEGER, of Kaiserslautern, in the Empire of Germany, Chemical
Engineer; do hereby declare the nature of this invention to be as follows:-
My invention relates to the manufacture of cyanides and to apparatus therefor.
The cyanides are produced from carbon, alkali and the nitrogen of the air at an
elevated temperature,
It consists substantially in mixing or bringing in contact the air, necessary on
the one hand for tlie combustion and on the other hand for giving off nitrogen, as
uniformly as possible with the reaction material so that the combustion and formation
of cyanide will coincide both in respect of time and space. This invention
relates moreover to the employment of certain arrangements and devices which
permit of the intimate contact of the air with the reaction material, the air being
either caused to enter at as many points as possible of a shaft filled with the
reaction material, or to circulate through pans the bottoms of which are covered
with the reaction material, or use being made of some other apparatus which
permits of the free and uniform admission of the air to the whole reaction
material. Lastly ny invention consists in making the walls of the reaction
chamber of magnesia for the purpose of protecting the same against deleterious
actions.
Dated this 20th day of Santamber 1894
HASELTINE, LAKE & Co.,
45. Southampton Buildings, London, W.C., Agents for the Applicant..
Improvements relating to the Manufacture of Cyanides and to
Apparatus therefor.
I, JOHANNES PFLEGER, of Kaiserslautern, in the Empire of Germany, Chemical
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 :-
My invention relates to the manufacture of cyanides from carbon, alkali and
nitrogen of the air at elevated temperatures and to apparatus therefor.
The said invention is based upon observations made by me which run directly
counter to the prevalent opinion and observations of others, regarding the most
suitable mode of carrying out the before mentioned process..
It is well known that, in carrying out this process in practice, if air is caused to
euter a chamber containing carbon, in a state of ignition, the carbon burns at the
point the air enters combining with the free oxygen and leaving the nitrogen
practically free from oxygen.
It is also well known that if the nitrogen thus freed from oxygen is caused to
enter into a chamber containing carbon and alkali. kept in a state of ignition by
heat applied externally it combines with the latter to form cyanide.

page_text: Heretofore in all endeavours to make cyanide by this means the air has been
freed of its oxygen before bringing it in contact with the reaction material (carbon
and alkali). This having been considered' essential' the air was dioxidized at as
grent aidistance as possible from the place where the cyanide was formed and in
fact the combustion chamber was completely separated from the reaction chamber,
or a special layer of carbon was provided to separate any free oxygon which might
have escaped combination in the combustion process before the nitrogen came in
contact with the reaction material, or else the air was previously deprived of its
oxygen by causing it to circulate. through incandescent metal such as copper, iron
and the like.
Now I have observed that under certain circumstances the presence of oxygen is
highly advantageous in effecting the reaction whereby the formation of the cyanide
proceeds more evenly, and more rapidly, while at the same time the yield is greater
and the temperature required is lower and the cost of production is less than when
the air has been first dioxidised.
This process may be.said to consist in intermingling air intimately and uniformly
with the, reaction material while ignited, or bringing it in contact therewith and
allowing local combustion to proceed' in the whole material. By this means the
oxygen producing local combustion of the carbon results in a very uniform.tempe
rature throughout the reaction, material. which greatly facilitates the combination
of the nitrogen.with the reaction material.
.
For this purpose, use is advantageously made of 'flat bottomed covered chambers
over,which are spread the mixture of carbon and alkali' in. a thin layer and into
which air can be allowed to freely pass. The space between the material and the
cover.. of the chamber is such that only just so much air can be admitted
as is; required for local combustion to take place in the reaction materiál.. The
chambers are preferably, heated exteriorly from below, and only to such an extent
that the carbou lying on the bottom will begin to burn on the admission of air.
During this combustion by the presence of air the formation of cyanide will"
then proceed evenly and with a yield of about 95 to 98 per cent. of the theoretical
amount.
:
Under these circumstances I find that, the formation of the. cyanide, is completed
in about 3 hours, whereas 8 to 10 hours are needed in the current of nitrogen free
from oxygen. Moreover a far higher temperature is required for the formation of
cyanide than in my process...
The reaction product, which is the material left in the chamber, is next treated
in any known manner, in order to obtain the cyanide contained therein in the
required state.
Use may also be made of other -apparatus which permits in like manner the
admission of air to the reaction material and the consequent local.combustion within
the materiál:
The air may be allowed to enter, at atmospheric pressure or may be of a higher
or lower pressure.
As an equivalent for oxygen an oxidising agent, such as, potassium or sodium'
nitrate; or other compound capable of producing local combustion of carbon when
ignited, may be added to the reaction material to increase the intensity of local
combustion.
The term alkali" in this Specification' means oxides or carbonates of potassium,
sodium, calcium or barium and these compounds may be employed either separately
or as mixtures of any two or more.
It is well known that the reaction material has a deleterious effect upon, any.
lining used in the reaction chamber, but I have now. discovered that this may be
reduced to a minimum by lining the interior of the chamber. with magnesia moulded
into, suitable form and burnt.
The magnesia may be in its pure state, or commercial state of purity, or may.be
mixed with a little clay or other non-injurious material.

page_text: 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 I
claim is :-
:
I. In the process for the manufacture of cyanides from carbon, alkali, and nitrogen
of the air, the admission of air to the reaction material to enable the formation of
cyanides by local combustion as described.
II. In the process characterized in the first claim, the use of oxygen of the air
for the purpose of maintaining local combustion in the reaction material and
facilitating the formation of cyanides as described.
III. In the process characterized in the first claim, the use of oxygen for the
purpose of facilitating the combination of nitrogen with the reaction material as
described.
IV. In the process characterized in the first claim the use of an equivalent for
oxygen for the purpose of intensifying local combustion and facilitating the formation
of cyanides as described.
V. In the process characterized in the first claim, the use of magnesia to protect
the reaction chamber from the deleterious action of the reaction products as
described.
D
1
T
1007
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.