A New or Improved Method or Process for the Production of Alkaline Cyanides.
Year: 1892

page_text: Date of Application, 19th Jan., 1892-Accepted, 9th Apr., 1892
COMPLETE SPECIFICATION
A New or Improved Method or Process for the Production of
Alkaline Cyanides.
I, PIERRE ROGATIEN DE LAMBILLY of Boulevard Henri IV. Paris in the
Republic of France Chemist 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 :-
If a mixture of carbonate of potash or of soda or of barium in fine powder
with very finely powdered charcoal is exposed to a red heat, the carbonate is
reduced to anhydrous oxide. On passing a current of ammonia gas over this
mixture when at the said high temperature the gas is decomposed, the nitrogen in
the nascent state in the presence of the alkali and the carbon produces a cyanide.
When ammonia gas is passed over red hot carbon cyanide of ammonium
produced.
The new or improved process is based on a combination of these two facts and
consists in passing ammonia gas into a first tube or vessel containing carbon at a
red heat so as to form cyanide of ammonium and thence through a second tube or
vessel charged with a mixture of cyanides after reduction of the carbonate to the
state of anhydrous oxide. The cyanide of ammoni um formed in the first tube is
decomposed in the second by contact with the alkali, to form cyanogen which is
absorbed by the alkali, and ammonia which is further decomposed in contact with
the alkali and carbon to form cyanide.
If the ammonia were passed direct over the alkali mixture there would be a
considerable loss of gas not utilized this loss is much reduced by first producing
cyanide of ammonia. To utilize more completely the gas, the apparatus may
moreover be arranged in series in the same furnace or in two distinct furnaces of
tubes, two and two, one being charged with carbon the other with the alkali
mixture. The reactions above described will then proceed alternately until the gas
is practically entirely used up.
In carrying this invention into effect three principal operations are necessary-
1st. The preparation of the mixture to be converted into cyanide. A very concen-
trated solution of say 100 parts of carbonate of potash or soda is made, and in this
solution powdered charcoal say 50 parts is poured. The solution is then evaporated
to dryness and when dry the mixture is broken up and mixed with about 20 parts
of powdered chalk to facilitate the reduction of the carbon by maintaining the
porosity of the mass. It is desirable to make this mixture into briquets by adding
about 10 parts of coal tar or resin, the presence of a hydrocarbon facilitates the
reaction. 2nd. The reduction of the alkaline carbonate. The mixture so far
prepared when heated to redness gives off carbonic oxide gas into which the
carbonic acid of the carbonate is transformed by the carbon, and this gas continues
to be given off until the tension no longer exceeds the pressure of the atmosphere.
At this moment it is advantageous to carry the reaction further by submitting the
mass to the action of a vacuum by drawing off the gases as they are formed so as
to maintain a vacuum in the tube or vessel. 3rd. The production and passage of
the ammonia. When the aforesaid reduction is adjudged sufficiently completed,
the gaseous ammonia is passed in. This gas may be produced in the usual way
by decomposition of an ammonia salt by heat in the presence of chalk. It is
preferable to choose a salt which can be decomposed in a dry or nearly dry state,
but if water is present or has to be added in the decomposition of the ainmonia
salt the gas passing over is dried by passing through any suitable drying material
before it is passed over the alkali mixture prepared as above described.

page_text: Having now particularly described and ascertained the nature of this said inven-
tion and in what manner the same is to be performed I declare that what I
claim is:
1. The method of producing cyanides by passing ammonia gas over a mixture
of carbonate of potash or soda and carbon at a red heat.
2. The method of producing cyanides by passing ammonia gas over red hot
carbon to produce cyanide of ammonium and passing said cyanide of ammonium
over a mixture of carbonate of potash or of soda with carbon also at a red
heat.
3. The method of producing cyanides by passing ammonia gas over red hot
carbon to produce ammonium cyanide and passing the resulting gases over a
mixture resulting from the heating of carbon and carbonate of potash or of soda
until the carbonic acid has been driven off as herein stated, the whole substantially
as described.
Dated this 10th day of January 1899
HERBERT & Co.,
18, Buckingham Street, Strand, London, W.C., Agents to Applicant.