Improvements in the Manufacture of Alkali Cyanides.
Year: 1894

page_text: Date of Application, 10th Nov.. 1894
Complete Specification Left, 10th Aug., 1895-Accepted, 14th Sept., 1895
Improvements in the Manufacture of Alkali Cyanides.
I HAMILTON YOUNG CASTNER of 13 & 14 Abchurch Lane in the City of
London Managing Director of The Aluminium Company Limited do hereby declare
the nature of this invention to be as follows:-
In Patent Applications dated the 23rd June 1891 Nos. 12,218-9, I have
described and shown a method for the production of alkali cyanide by employing
the alkali metal as a starting point and combining same with either nascent or
combined nitrogen and carbon (either in the nascent state or in one of its ordinary
forms). The nitrogen either in the nascent state or nitrogen combined with a
certain quantity of hydrogen being produced by the decomposition of anhydrous
ammonia. In carrying on the said processes while the ultimate product is alkali
cyanide several intermediate reactions take place more or less due to the heat
employed and varying quantities of materials present and this renders it difficult
to carry on the manufacture without considerable care to avoid loss of nitrogen.
I have found by experiment that such loss can be avoided if I carry on the process
in two separate steps or reactions.
Thus a product closely approaching the theoretical yield from the amount of
alkali metal and ammonia employed can be obtained and the general character of
the process will be much simplified. In this manner the process may either be
carried on continuously or intermittently. Briefly stated therefore the present
invention while depending upon the same principle as to the employment of the
alkali in the metallic form, particularly relates to carrying on the process in two
steps whereby an intermediate product is actually obtained and which is then
directly and separately converted into alkali cyanide. The first step of the process
consists in passing anhydrous ammonia over metallic sodium heated to a temperature
of between 300 and 400° C. and thereby producing amide of the alkali metal the
reaction being
carrying out the manufacture.
Figure 1 is a sectional elevation of the furnace A in which is set the rectangular
iron retort B having an inclined bottom.
Figure 2 is a horizontal section of the upper half of the iron retort.
Figure 3 a section of the retort through the line x-y in Figure 1, and
Figure 4 is a vertical iron retort in which the second step of the process is
carried on.
The upper
half of the retort B is provided with partitions c which reach down so
as to project into the bath of molten alkali metal D. Opposite ends of these
partitions are cut away as shown in Figure 2 so as to compel the passage of any
vapour or gas to take the direction shown by the arrows. The upper half is

page_text: furthermore provided with a branched inlet pipe L, an outlet pipe M, and a swan-
neck inlet pipe and hopper N, which is also provided with a valve O. The bottom
half of the retort is provided with partitions E and F, the former rising above the
level of the latter and the partition H which rises above the level of F and which
partition has several openings at the bottom shown at K. The bottom is further-
more provided with an outlet pipe P and a swan-neck outlet pipe R.
Figure 4 shews a vertical iron retort S set in furnace T. This retort is provided
with a funnel entrance pipe U, a hopper V, a gas outlet pipe W, and a swan-neck
outlet pipe Z.
In carrying on the process the retort, Figure 1, is raised to a temperature of
between 300 and 400° C. Perfectly dry ammonia gas is then allowed to enter
through the pipe L' and L in order to expel the air. Metallic sodium which is
melted in N is then allowed to flow in until it rises to the level of the dotted line
between E and H and overflowing at F it passes out through R when the supply is
temporarily stopped. The flow of ammonia gas is now regulated to the ascertained
capacity of the retort and the proportionate quantity of sodium introduced through N
at intervals, that is, for every 17 lbs. of ammonia gas introduced 23 lbs. of sodium
must be added. The amide forming on the surface of the molten sodium, melts,
sinks to the bottom, flowing along the same and gradually fills the space between H
and F expelling the sodium through the pipe R. The overflow of amide then
becomes regular, and may be collected in closed vessels for future treatment with
carbon or it may be allowed to flow direct into the retort S through the opening U.
This retort having been heated to dull redness and filled with charcoal through the
hopper V. The reaction here taking place producing hydrogen and cyanide the
former escaping through the opening W while the latter fuses, filters through
the bed of charcoal and escapes through the opening Z into receptacles placed for
its reception. Fresh carbon is introduced from time to time to replace that used in
the formation of the cyanide.
The gas escaping from the pipe M will consist of hydrogen together with a
small quantity of ammonia and is led through acid when the latter is absorbed for
reuse.
In stopping the apparatus some care is necessary owing to the presence of
hydrogen. The inlet pipe N, Figure 1, is closed by the tap O and while the
ammonia is still passing the charge of molten sodium and amide is drawn off
through the pipe P. This is then closed and either nitrogen or carbonic acid gas
admitted through LL while L'L is closed in order to sweep out all the ammonia
and hydrogen. It is thus possible to obtain pure alkali cyanide practically in one
continuous operation although by two separate and distinct reactions.
1 am quite aware it is not new to form an amide by passing ammonia over an
alkali metal although such an operation had no commercial application and was
merely of scientific interest. If the question was submitted to a competent chemist
he would probably reply that an amide decomposed in the presence of heated carbon
would produce cyanide, hydrogen and a small quantity of ammonia, and yet so far
as I am aware it has not heretofore been proposed to commercially manufacture
alkali cyanide by first making an amide and then decomposing same in the presence
of heated carbon. It is evident that in place of carbon it is quite possible to heat
the amide in an atmosphere of hydrocarbon to form the cyanide and in place of an
alkali metal being used an alkali alloy may be substituted.
Dated this 10th day of November 1894.
PHILIP M. JUSTICE,
55 & 56 Chancery Lane, London, Chartered Patent Agent,
For the Applicant.

page_text: Improvements in the Manufacture of Alkali Cyanides.
I, HAMILTON. YOUNG CASTNER of 13 & 14 Abchurch Lane, in the City of
London, Managing Director of The Aluminium Company Limited, 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:-
In Patent Applications dated 23rd June 1894, Nos. 1221804 and 1221904, I have
described and shown a method for the production of alkali cyanide by employing
the alkali metal as a starting point and combining same with either nascent or
combined nitrogen and carbon (either in the nascent state or in one of its ordinary
forms). The nitrogen either in the nascent state or nitrogen combined with a
certain quantity of hydrogen being produced by the decomposition of anhydrous
ammonia.
In carrying on the said processes while the ultimate product is alkali cyanide
several intermediate reactions take place more or less due to the heat employed
and varying quantities of materials present, and this renders it difficult to carry on
the manufacture without considerable care to avoid loss of nitrogen. I have found
by experiment that such. loss can be avoided if I carry on the process in two
separate steps or reactions. Thus a product closely approaching the theoretical
yield from the amount of alkali metal and ammonia employed can be obtained, and
the general character of the process will be much simplified. In this manner the
process may either be carried on continuously or intermittently: Briefly stated
therefore the present invention while depending upon the same principle as to the
employment of the alkali in the metallic form, particularly relates to carrying on
the process in two steps whereby an intermediate product is actually obtained and
which is then directly and separately converted into alkali cyanide. The first step
of the process consists in passing anhydrous ammonia over metallic sodium heated
to a temperature of between 300 and 400° C., and thereby producing amide of the
alkali metal the ronation bein
In the drawings accompanying the Provisional Specification I show a form of
apparatus well adapted for carrying out the manufacture.
Fig. 1 is a sectional elevation of the furnace A, in which is set the rectangular
iron retort B having an inclined bottom.
Fig. 2 is a horizontal section of the upper half of the iron retort.
Fig. 3 is a section of the retort through the line -y in Fig. 1, and
Fig. 4 is a vertical iron retort in which the second step of the process is
carried on.
The upper half of the retort B is provided with partitions C which reach down
so as to project into the bath of molten alkali metal D. Opposite ends of these
partitions are cut away as shown in Fig. 2 so as to compel the passage of any
vapour or gas to take the direction shown by the arrows. The upper half is
furthermore provided with a branched inlet pipe L, an outlet pipe M, and a swan-
neck inlet pipe and hopper N which is also provided with a valve O. The bottom
half of the retort is provided with partitions E and F, the former rising above

page_text: the level of the latter and the partition H which rises above the level of F, and
which partition bas several openings at the bottom shown at K. The bottom is
furthermore provided with an outlet pipe P and a swan-neck outlet pipe R.
Fig. 4 shews a vertical iron retort S set in furnace T. This retort is provided
with a funnel entrance pipe U, a hopper V, a gas outlet pipe W, and a swan-neck
outlet pipe Z.
In carrying on the
between 300 and 400° process the retort, Fig. 1, is raised to a temperature of
Perfectly dry ammonia gas is then allowed to enter
through the pipe L' and L in order to expel the air. Metallic sodium which is
melted in N is then allowed to flow in until it rises to the level of the dotted line
between E and H, and overflowing at F it passes out through R when the supply
is temporarily stopped. The flow of ammonia gas is now regulated to the
ascertained capacity of the retort, and the proportionate quantity of sodium
introduced through N at intervals, that is, for every 17 lbs. of ammonia gas
introduced 23 lbs. of sodium must be added. The amide forming on the surface
of the molten sodium melts, sinks to the bottom, flowing along the same and
gradually fills the space between H and F expelling the sodium through the
pipe R. The overflow of amide then becomes regular, and may be collected in
closed vessels for future treatment with carbon, or it may be allowed to flow direct
into the retort S through the opening U. This retort having been first heated to
dull redness and filled with charcoal through the hopper V, the reaction here
taking place producing hydrogen and cyanide, the former escaping through the
opening W, while the latter fuses, filters through the bed of charcoal and escapes
through the opening Z into receptacles placed for its reception. Fresh carbon is
introduced from time to time to replace that used in the formation of the cyanide.
The gas escaping from the pipe M will consist of hydrogen together with a small
quantity of ammonia and is led through acid when the latter is absorbed for
reuse.
In stopping the apparatus some care is necessary owing to the presence of
hydrogen. The inlet pipe N, Fig. 1, is closed by the tap O, and while the ammonia
is still passing the charge of molten sodium and amide is drawn off through the
pipe P.
This is then closed and either nitrogen or carbonic acid gas admitted
through LL while L' L is closed in order to sweep out all the ammonia and
hydrogen. It is thus possible to obtain pure alkali cyanide practically in one
continuous operation although by two separate and distinct reactions.
I am quite aware it is not new to form au amide by passing ammonia over an
alkali metal although such an operation has had no commercial application and was
merely of scientific interest. In the same way it was I believe known in the
aboratory that an amide decomposed in the presence of heated carbon would
produce cyanide, hydrogen and a small quantity of ammonia, and yet so far as
I am aware it has not heretofore been proposed to commercially manufacture
alkali cyanide by first making an amide and then decomposing same in the presence
of previously heated carbon. It is evident that in place of carbon it is quite
possible to beat the amide in an atmosphere of hydrocarbon to form the cyanide
and in place of an alkali metal being used an alkali alloy may be substituted.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is :-
1. The improvements in the manufacture of alkali cyanides consisting in first
producing an amide by decomposing anhydrous ammonia in the presence of an
alkali metal maintained at a temperature as set forth, and then converting the
amide into cyanide by decomposing it in the presence of carbon heated previously
to the admission of the amide as described.
2. The improvements in the manufacture of alkali cyanides consisting in
introducing molten alkali metal at a temperature of about 300 to 400-C. into an a
atmosphere of anhydrous ammonia in the proportions of about 23 pounds of alkali

page_text: metal for each 17 pounds of ammonia gas, withdrawing the amide produced and
decomposing it by passing it through carbon heated to redness previously to the
admission of the amide and collecting the resulting cyanide.
3. In apparatus for the manufacture of alkali cyanides an externally heated
retort provided with gas inlet and discharge pipes and inlet pipes for the molten
alkali inetal, means for causing the gas to come into intimate contact with the
metal, and means for drawing off the amide produced.
4. In apparatus for the manufacture of alkali cyanides an externally heated
retort provided with baffle plates dipping into the molten metal, an end plate with
bottom openings through which the produced amide passes, and an overflow plate
and discharge pipe for same.
Dated the 9th day of August 1895.
PHILIP M. JUSTICE,
55 & 56 Chancery Lane, London, Chartered Patent Agent,
For the Applicant.