Improvements in the Obtainment of Cyanogen Compounds.
Year: 1899

page_text: Improvements in the Obtainment of Cyanogen Compounds.
I, JAMES MACTEAR, of 28, Victoria Street, Westminster, Chemical Engineer,
do hereby declare the nature of this invention to be as follows:-
This invention relates to the production of alkaline cyanides and cyanogen com-
pounds and has special reference to the obtainment, in an improved manner, of
ammonium cyanide, from which potassium cyanide, sodium cyanide or a mixture
of such cyanides or other cyanogen compounds may be readily obtained, the
object of the invention being to enable such products to be obtained at a reduced
cost and to avoid the production of useless bye-products in their obtainment.
To this end, the invention is based on the reaction which takes place between
gaseous ammonia and gascous carbonic, oxide when a mixture of such gases is
submitted, under suitable conditions, to a sufficient temperature to decompose.
such gases, and consists in the obtainment of ammonium cyanide by submitting
a gaseous mixture of ammonia and carbonic oxide, or of ammonia, carbonic oxide
and nitrogen, in a decomposing chamber charged with a suitable catalytic sub-
stance, and heated internally by the employment of an electrical resistance and
also externally either by the like means or by gaseous fuel, to a temperature
sufficient to decompose the gases and to cause the formation of ammonium cyanide.
In order to keep the volume of the gases entering into the reaction as low as
possible, I prefer that the gaseous carbonic oxide used in the process should be as
pure as possible. It can be obtained in a condition specially suitable for the said
process by leading carbonic acid (produced by the decomposition of carbonate of
lime by heat in closed vessels or in any other known way) into closed vessels
charged with coke or carbon and sufficiently heated to decompose the carbonic
acid and produce carbonic oxide, which is then led through suitable purifying
vessels to eliminate any carbonic acid or sulphur compounds.
But where the volume of the gases to be dealt with is not of material importance,
I may use, in lieu of carbonic oxide, a mixture of carbonic oxide with nitrogen
or with nitrogen and hydrogen such as may be obtained by the limited com-
bustion of carbonaceous matter with air or with air and steam such as "producer"
gas, or Dowson" gas.
The gaseous ammonia used in the process may also be produced in any known
way, but can be produced in a condition specially suitable for my improved pro-
cess by distilling ammonium sulphate with caustic lime.
In submitting such gases (say, for example, the gaseous ammonia and the
gaseous carbonic oxide,) to the process of the invention, they are firstly mixed in
a closed chamber in the respective proportions of about two volumes of the gascous
ammonia and one volume of the gaseous carbonic oxide, being conveniently
supplied to such chamber in such proportions by the use of two rotary pumps or
blowers of such respective sizes and driven at such respective speeds as will supply
the respective gases in the required respective proportions.
From such chamber the gaseous mixture is led into a decomposing and recom-

page_text: posing chamber which is charged with wood charcoal or other suitable catalytic
substance, and is heated to a temperature (approximately 1800° to 2000° Fah.)
sufficient to decompose the gaseous, mixture and to cause, as the products of the
reaction, the formation of ammonium cyanide and water, which are led from
the chamber. Should it be required to produce alkaline cyanides, the
products of the reaction in the decomposing chamber are led from
the chamber into suitable absorbing vessels, containing alkaline hydrates,
in solution in water or alcohol, such as caustic potash when potassium
cyanide is required or caustic soda when sodium cyanide is required; with the
formation of the required alkaline cyanide, and liberation of the ammonia of the
ammonium cyanide which is recovered and may again be used in the cycle of
operations. The products of the reaction in the decomposing chamber should be
cooled before entering the absorbing vessels which should be kept as cool as
possible.
The solution of the alkaline cyanide or mixture of cyanides obtained is
evaporated, preferably in vacuo, and the cyanide may be either prepared for sale
as a crystalline mass or may be fused.
Other cyanogen compounds may also be produced from the ammonium cyanide
obtained as aforesaid, by any known means.
I prefer to use for the decomposition of the gaseous mixture a closed chamber
heated internally by the employment of an electrical resistance, in addition to its
being heated externally, which latter may be done either by the like means of an
electrical resistance, but for economy may be effected by the use of gaseous fuel.
in any suitable manner, as by the employment of such means of internally heating.
the decomposing chamber, I am enabled to obtain a practically equal temperature.
throughout the chamber and can make the latter of such a size and internal
dimensions as will enable the process to be carried out on a commercial scale and
in an economical manner.
DAY, DAVIES & HUNT,
Chartered Patent Agents,
321, High Holborn, London, W.C.,
Agents for the Applicant.
I, JAMES MACTEAR, of 28, Victoria Street, Westminster, 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:-
This invention relates to the production of alkaline cyanides and cyanogen
compounds, its objects being to enable such products to be obtained at a reduced
cost and to avoid in their obtainment the production of useless bye-products.
To this end, the invention is characterized by the obtainment of ammonium
cyanide by submitting a mixture of gaseous ammonia and gaseous carbonic oxide,
in a decomposing chamber, (preferably charged with a suitable catalytic sub-
stance) heated internally by the employment of an electrical resistance to a
temperature sufficient to decompose such gaseous mixture and to cause the forma-
tion of the ammonium cyanide, and by the obtainment of ammonium cyanide in
such manner as a step in the production of other alkaline cyanides and cyanogen
compounds.

page_text: In carrying out the invention the gaseous ammonia and the gaseous carbonic
oxide are firstly mixed in the respective proportions of about two volumes of the
gaseous ammonia and one volume of the gaseous carbonic oxide in a closedl
chamber, to which they may be conveniently supplied by rotary pumps or blowers
of such respective sizes and driven at such respective speeds as will supply the
respective gases in the required proportions, and from which the gaseous mixturé
is led into the decomposing chamber wherein the mixture is heated to a tempera-
ture (approximately 1800° to 2000° Fahrt.) sufficient to decompose it, and to cause,
as the products of the reaction, the formation of ammonium cyanide and water.
These products are led from the chamber and cooled, and, if, say, alkaline
cyanides are required, are led into suitable absorption vessels containing appro-
priate alkaline hydrates in solution in water or alcohol, such, for example, as
caustic soda when sodium cyanide is required, or caustic potash when potassium
cyanide is required, or a mixture of caustic soda and caustic potash when a mixture
of sodium and potassium cyanides is required, with the consequent formation of
the required cyanide or cyanide mixture, and liberation from the ammonium
cyanide of the ammonia, which latter may be recovered and may again be used in
the cycle of operations.
The solution of the alkaline cyanide or mixture of cyanides thus obtained is
evaporated, preferably in vacuo, and the resultant cyanide or mixture of cyanides
may be prepared for sale as a crystalline mass or may be fused.
If ferrocyanides or other cyanogen compounds are required, the cooled products
from the decomposing chamber are in like manner submitted to the action of
known means of obtaining such compounds from ammonium cyanide.
To keep the volume of the gases entering into the aforesaid reaction in the pro-
duction of the ammonium cyanide as small as possible, the gaseous carbonic oxide
should be used as pure as obtainable, and to this end, I prefer that it should be
obtained by decomposing carbonic acid in sufficiently heated closed vessels chargedl
with coke or carbon and by freeing the resultant carbonic oxide from any carbonic
acid in suitable purifying vessels.
If, however, for any reason, the volume of the gases to be dealt with is not of
material importance, a mixture of gaseous carbonic oxide with nitrogen or with
nitrogen and hydrogen (such as may be obtained by the limited combustion of
carbonaceous matter with air or with air and steam, such as producer gas
66
or
Dowson gas") may be used (in lieu of the gaseous carbonic oxide) in mixture
with the gaseous ammonia.
The gaseous ammonia used in the process may be produced in any known way,
but can be obtained in a specially suitable condition for the purpose of the inven
tion by distilling ammonium sulphate with caustic lime.
The heating of the decomposing chamber internally by the employment of an
electric resistance is of special utility and advantage in enabling a practically equal
temperature throughout the chamber to be obtained, which is so essential a
requirement to the economical obtainment of the required products, and also in
enabling the chamber to be made of such a size and of such internal dimensions
as will enable the process to be carried out on a commercial scale with considerable
economy as compared with existing means of obtaining the required products.
The accompanying drawings represent one form of electrical furnace such as
I employ in carrying out my invention; Figure 1, representing. the same in
sectional elevation on the line 1-1, Fig. 2; and Figure 2, representing the same
in scctional plan on the line 2-2, Fig. 1.
, represents a vertically arranged chamber made of porcelain or other suitable
refractory material and formed of an oblong shape (Fig. 2) with open ends and
flanged extensions a¹, the end faces of which are each formed with a surrounding
annular channel a², which communicates with the interior of the chamber by
lateral perforations a³.
The chamber ends are closed by covers b, each of which is formed with through
openings, adapted to communicate with the adjacent channels a³, of the

page_text: chamber. The openings 61, at the inlet end of the chamber communicate by
branched piping 2, with a main 3, leading from the mixing chamber of the
gases to be decomposed, and the openings 1, at the outlet end of the chamber
communicate by branched piping 64, with a main b, by which the products of the
reaction of the gases in the chamber are led to the absorption vessels wherein the
ammonium cyanide is converted into the alkaline cyanide or other cyanogen
compound required.
The chamber ends and its end covers are luted together at d, by a suitable
The bottom end of the
cement and are also bound together by metal bands e.
chamber is made with an inner ledge a, serving to support a perforated false
bottom f, by which the catalytic substance g, employed (say, wood charcoal) is
supported.
The chamber is heated internally by a series of electrical resistances h, pre-
ferably in the form of coils of platinum wire wound upon a support of refractory
material mounted in a tube j, of refractory material passing into or through the
chamber, the resistances being connected in series or otherwise with a dynamo
or other source of electric energy by means of which their temperature can be
raised to such a point as will give the required equal temperature in the spaces
between the adjacent tubes j, and also in those between each thereof and the
adjacent sides of the chamber, whereby the desired equable temperature of the
whole interior of the decomposing chamber is effectually obtained.
To prevent loss of heat by radiation, and to assist in maintaining the internal
equable temperature, the chamber is or may also be heated externally, and this,
where the electric current can be obtained at a low cost, may also be effected by
a resistance coil or coils wound around the chamber, but, in other cases, is pre-
ferably effected by gaseous fuel, in which case, a suitable combustion chamber or
flues would be required to be built around the chamber.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. The production of ammonium cyanide by the decomposition of a gaseous
mixture of carbonic oxide and ammonia, carbonic oxide ammonia and nitrogen,
or carbonic oxide ammonia nitrogen and hydrogen, in decomposing chamber
heated internally and equably throughout by an electrical resistance surrounded
by the gaseous mixture under treatment, as set forth.
2. The production of ammonium cyanide by the decomposition of a gaseous
mixture of carbonic oxide and ammonia alone, or with nitrogen or nitrogen and
hydrogen in decomposing chamber heated internally and equably throughout by
an electrical resistance and also externally by like means or by gaseous fuel so that
such gaseous mixture will both surround and will be surrounded by the source
of heat by which its decomposition is effected, as set forth.
3. The production of alkaline cyanides and cyanogen compounds by the pro-
duction of ammonium cyanide by the respective process and means referred to in
the preceding respective claims, the conversion of the ammonium cyanide so
obtained into the desired alkaline cyanide or cyanide mixture or cyanogen com-
pound by the action of appropriate alkaline hydrates or means of obtaining the
required products in solution in water or alcohol, with liberation from the
ammonium cyanide of the ammonia, and the evaporation of the solution of the
cyanide or cyanide mixture or cyanogen compound so obtained, as set forth.
4. A decomposing chamber adapted especially for producing ammonium cyanide
from a mixture of gaseous ammonia and gaseous carbonic oxide alone, or with
nitrogen or nitrogen and hydrogen, but applicable for decomposing other gaseous
mixtures, characterized by being made of an oblong shape with open ends and
perforated flanged extensions fitted with perforated end covers cemented and metal
bound thereto and serving to lead the mixed gases from a branched main to the
chamber interior and the resultant products from the chamber to a branched

page_text: outlet main, and by being fitted internally with a perforated support to a filling
of suitable catalytic substance and with a series of refractory tubes equi-spaced
as regards each other and also as regards the chamber sides and containing electric
coils or resistances adapted to heat the chamber equably throughout from the
inside, as set forth.
5. An apparatus for decomposing gaseous mixtures, comprising a body having
open ends, a flat cover and bottom fitting said ends, tubes of refractory material
inserted through and depending from the cover and spaced equi-distant from each
other and from the sides of the body, said tubes having closed lower ends, electric
resistances inside of each tubes, and pipes for supplying the gaseous mixture and
drawing off the products of its treatment, as set forth.
6. An apparatus for decomposing gaseous mixtures, comprising a body having
flanged and perforated ends, a flat bottom and cover having corresponding per-
forations, a perforated diaphragm supported shortly above said bottom, a catalytic
substance nearly filling the body above said diaphragm, pipes connecting with the
perforations in the cover and bottom, tubes of refractory material depending from
the cover into the catalytic substance and spaced equidistant from each other and
from the sides of the body, and electric resistances arranged within said tubes,
as set forth.
7. An apparatus for decomposing gaseous mixtures, comprising a body provided
with removable cover and bottom, a catalytic substance contained in said body,
refractory tubes depending into said substance, electric resistances within said
tubes, and means for applying heat to the outside of the body, as set forth.
S. An apparatus for decomposing gaseous mixtures, comprising a body pro-
vided with a flat cover, tubes of refractory material depending from said cover,
a catalytic substance nearly filling the body around said tubes, and electric heaters
within said tubes and surrounding said body, as set forth.
Dated this 10th day of August 1899
DAY, DAVIES & HUNT,
Chartered Patent Agents,
321, High, Holborn, London, W.C.,
Agents for the Applicant.