Process and Apparatus for the Manufacture of Cyanides.
Year: 1891

page_text: Date of Application, 18th Mar., 1891
f
Complete Specification Left. 18th Jan.. 1892-Accepted, 18th June, 1892
PROVISIONAL SPECIFICATION.
Process and Apparatus for the Manufacture of Cyanides.
I GEORGE THOMAS BEILBY of St. Kitts Slateford, Midlothian, Chemical
Engineer do hereby declare the nature of this invention to be as follows:-
I
pass ammonia over or through a mixture of alkali with alkaline cyanide and
finely divided carbon at a temperature sufficiently high to keep the mixture fluid
and to decompose the ammonia. By this means carbon and ammonia are consumed
and a large part of the alkali is converted into cyanide. The fused cyanide which
is obtained contains a small percentage of finely-divided carbon which is removed
by settling or filtration.
As it is desirable that the operation should be conducted at as low a temperature
as possible so as to avoid waste of materials or damage to the apparatus, the
proportions of the several ingredients, are so adjusted that the mixture is fluid at
a temperature below that at which iron would be rapidly destroyed. In practice
I have found that a mixture containing about 20 per cent. of cyanide of potassium,
20 to 25 per cent. of carbon and 55 to 60 per cent. of carbonate of potassium melts
at a sufficiently low temperature, but I do not restrict myself to any exact pro-
portions as these must vary more or less according to the materials used and to the
form of apparatus used. In certain of the forms of apparatus which I am about to
describe the cyanide necessary for the fusion can be formed in the mixture of
carbon and alkali after it has entered the apparatus.
The process may be carried out in a melting pot provided with an inlet pipe for
ammonia, an outlet pipe for the gases evolved in the process, an opening or hopper
for the introduction of the solid materials, and a tap hole for running off the finished
cyanide.
When the mixture in the pot has been brought into a state of fusion ammonia is
brought into intimate contact with it either by bubbling the ammonia through the
fluid, or by breaking up the fluid by mechanical stirrers while the ammonia gas is
passed through the pot.
Throughout the operation it is important to have a sufficient proportion of cyanide
in the mixture to render it thoroughly fluid otherwise the mass froths up and is apt
to choke the exit pipe.
As the mixture becomes more fluid by the formation of further quantities of
cyanide, fresh quantities of alkali and carbon are added from time to time till the
pot is filled to its fullest working capacity. The supply of ammonia is then kept up
till the desired proportion of cyanide is obtained, after which the fused salt is settled
or filtered and run into moulds or drums.
The gases from the process, containing undecomposed ammonia, may be led
through other melting pots or may be led directly from the first pot to washers or
absorbers for the recovery of the ammonia. Or the gases from the pot or pots may
be led through tubes containing an infusible mixture of carbon and alkali kept at
a suitable temperature for the production of cyanide.
My process for the production of cyanides may be carried out in a more continuous
manner in vertical retorts kept at a suitable temperature by any convenient
arrangement of furnace and flues. The bottom of the retort is closed and forms a
melting pot in which the cyanide collects and from which it is periodically run off.
Ammonia is led in to the lower part of the retort. The lower part of the body of
the retort is fitted with perforated shelves. A central revolving shaft carries disks
or arms which stir and sweep the mixture on the shelves and cause it to drop from
shelf to shelf. A mixture of alkali and carbon, with or without cyanide according
to circumstances, is fed through a suitable hopper at the top of the retort and drops-

page_text: on to the top shelf where it is acted on by the ammonia with the formation of some
cyanide which makes it fuse and drop to the next shelf. The revolving arms keep
the imperfectly fused mixture on the top shelves from frothing up in a dangerous
way and mix and drive forward the molten mass.
With mixtures which are very fluid at moderate temperatures it is possible to
dispense with the moving shaft. In this case the mixture of alkali, carbon and
cyanide is fed into the upper part of the retort through a perforated or grated tube
which passes down for some distance into the retort. Or the mixture may be fed
through the annulus between the tube and the retort walls. The perforations or
gratings of the feed tube are so arranged that the mixture can only pass into the
retort as it softens and melts by the action of heat and ammonia.
The retorts are provided at their upper ends with exit pipes for the gases which
are dealt with in any of the ways described as applicable to the gases from
the process as carried out in melting pots.
The alkali I prefer to use is carbonate of potassium. The carbon may be
supplied by charcoal, lampblack, coke or pitch or any other convenient source.
By using pitch made from the basic tars of crude shale or coal oil or peat tar
I am able to recover a large part of its nitrogen as cyanide.
I can also, to a certain extent, use the volatile bases from crude shale or coal
oils or peat tar, or from animal or bone oil, instead of ammonia.
In some cases I add a proportion of finely-divided iron to the mixture of alkali
and carbon or alkali cyanide and carbon.
Dated this 17th day of March 1891.
GEORGE THOMAS BEILBY,
Applicant.
COMPLETE SPECIFICATION.
Process and Apparatus for the Manufacture of Cyanides.
I, GEORGE THOMAS BEILBY, St. Kitts, Slateford, Midlothian, 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 has for its object the direct production of simple cyanides of high
or of moderately high percentage in a convenient and marketable form, and it
consists in a process whereby such cyanides are produced by passing ammonia over
or through a liquid fused mixture of anhydrous alkali and alkaline cyanide with
finely divided carbon, and to suitable apparatus for carrying such process into
effect.
I pass ammonia over or through a mixture of anhydrous alkali with alkaline
cyanide and finely-divided carbon at a temperature sufficiently high to keep the
mixture fluid and to decompose the ammonia. By this means carbon and ammonia
are consumed and a large part of the alkali is converted into cyanide. The fused
cyanide which is obtained contains a small percentage of finely-divided carbon
which may be removed by settling or filtration.
As it is 'desirable that the operation should be conducted at as low a temperature
as possible so as to avoid waste of materials or damage to the apparatus, the
proportions of the several ingredients are so adjusted that the mixture is fluid'at a
temperature below that at which iron would be rapidly destroyed. In practice I
have found that a mixture containing about 20 per cent. of cyanide of potassium,
20 to 25 per cent. of carbon, and 55 to 60 per cent. of carbonate of potassium, melts
at a sufficiently low temperature; but I do not restrict myself to any exact pro-
portions as these must vary more or less according to the materials and to the form
of apparatus used.
The process may be carried out in a melting pot provided with an inlet pipe for
ammonia, an outlet pipe for the gases evolved in the process, an opening or hopper

page_text: for the introduction on те копи шабетта, ап
finished cyanide.
When the mixture in the pot has been brought into a state of fusion, ammonia is
brought into intimate contact with it either by bubbling the ammonia through the
fluid or by breaking up the fluid by mechanical means, while the ammonia gas is
passed through the pot.
Throughout the operation, it is important to have a sufficient proportion of
cyanide in the mixture to render it thoroughly fluid, otherwise the mass froths up
and is apt to choke the exit pipe, or otherwise to interfere with the proper carrying
out of the process.
As the mixture becomes more fluid by the formation of further quantities of
cyanide fresh quantities of alkali and carbon may be added from time to time, till
the pot is filled to its fullest working capacity, or the full charge may be introduced
into the pot before the ammonia is turned ou. The supply of ammonia is then kept
up till the desired proportion of cyanide is obtained, after which the fused salt may
be settled or filtered or is directly run into moulds or drums, and is ready for the
market.
The guses from the process containing undecomposed ammonia may be led through
other melting pots or may be led directly from the first pot to washers or absorbers
for the recovery of the ammonia. Or the gases from the pot or pots may be led
through tubes containing an infusible mixture of carbon and alkali, kept at a
suitable temperature for the production of cyanide.
In carrying out my invention even when the operation in the melting pot is
conducted at a temperature somewhat below the melting point of carbonate of
sodium, and therefore much below the boiling point of the cyanide of potassium or
of sodium, the gases as they leave the melting pot carry with them a considerable
quantity of alkaline cyanide. At higher temperatures correspondingly larger
quantities of cyanide are carried over by the gases. I therefore employ a suitable
chamber or chambers through which the gases are caused to pass on their way to
the scrubbers or other apparatus above referred to for the recovery of the ammonia.
In these chambers the fumes of cyanide condense and deposit, and the condensed
product is removed therefrom from time to time.
If the gases contain any water vapour the chambers are maintained at a
sufficiently high temperature (either by a steam jacket or other suitable means) to
prevent its condensation, so that the cyanide may be recovered in a dry condition.
The cyanide obtained may be used in the form in which it is deposited, but if
desirable it may be remelted and run into moulds or drums, or it may be returned
to the melting pot and drawn off with the rest of the cyanide.
It is obvious that the greater or less volatilization of the cyanide from the
melting pot is a question of time, temperature and volume of gas passing through,
and if it were desirable the process might be worked so that the greater part of the
cyanide might be sublimed over and drawn off from the chamber as sublimate instead
of from the melting pot as fused salt.
My process for the production of cyanide may be carried out in a more continuous
manner in vertical retorts, kept at a suitable temperature by any convenient
arrangement of furnace and flues. The bottom of the retort is closed and forms a
melting pot in which the cyanide collects, and from which it is periodically run off.
Ammonia is led into the lower part of the retort. The lower part of the body of
the retort is fitted with perforated shelves. A central revolving shaft carries
discs or arms which stir and sweep the mixture on the shelves, and cause it to drop
from shelf to shelf. Or the perforated shelves may be carried by the revolving
shaft and the arms which sweep saine be fixed to the body of the retort. A mixture
of alkali, carbon and cyanide is fed through a suitable hopper at the top of the
retort, and drops on to the top shelf, where it is acted upon by the heat and
ammonia. The arms or discs sweep the shelves and cause the fused mixture to drop
through the perforations of such shelves, the ammonia as it passes up through the
retort coming into intimate contact with such fused mixture as it falls from shelf to

page_text: shelf, forming fresh quantities of cyanide, so that by the time the liquid reaches the
melting pot at the bottom it contains a large percentage of cyanide. The revolving
arms keep the imperfectly-fused mixture on the top shelves from frothing up in a
dangerous way and mix and drive forward the molten mass.
With mixtures which are very fluid at moderate temperatures, it is possible to
dispense with the revolving shaft. In this case the mixture of alkali, carbon and
cyanide may be fed into the upper part of the retort, through a perforated or grated
tube which passes down for some distance into the retort. Or the mixture may be
fed through the annulus between the tube and the retort walls. The perforations
or gratings of the feed-tube are so arranged that the mixture can only pass into the
retort as it softens and melts by the action of heat. Or again, the mixture of
alkali, carbon and cyanide is brought into a state of tranquil fusion in a separate
portion of the apparatus, and is thence allowed to flow in a regulated stream down
through the vertical retort with perforated shelves.
The retorts are provided at their upper ends with exit pipes for the gases, which
are dealt with in any of the ways described as applicable to the gases from the
process as carried out in melting pots.
The apparatus for carrying my invention into effect may vary, several suitable
forms of such apparatus being illustrated in the accompanying drawings, in which
Fig. 1 is a vertical section of one form of apparatus suitable for the purpose.
Fig. 2 is a horizontal section of Fig. 1 on line x, .
Fig. 3 is a horizontal section of Fig. 1 on line y, y.
Fig. 4 is a front elevation at right angles to Fig. 1, showing particularly the
chamber used for recovering cyanides from the gases leaving the melting pot.
Fig. 5 is a vertical section of an apparatus in which the fused mixture is caused
to drop from shelf to shelf and in its descent is brought into contact with an
ascending current of ammonia.
Fig. 6 is a modification of the apparatus shown in Fig. 5.
Similar letters of reference indicate corresponding parts in all the figs. where
they occur.
Referring to the apparatus illustrated in Figs. 1 to 4 inclusive :-
The melting pot A of cast iron is built in an oven heated by a furnace B and
flues C. It is provided with one or more tap holes a, a', with plugs which can be
opened or closed from the outside of the structure. The upper part of the pot is
covered by a plate or blind flange through which the ammonia tube D passes. The
ammonia tube may be simply open at its lower end or it may terminate in perforated
branch pipes or in a perforated rose distributor d. The object aimed at in the
introduction of the ammonia being that it shall come into intimate contact with the
fluid in the pot, the arrangement which does this most effectively will be the best.
Instead of one large ammonia pipe and distributor a number of smaller pipes may
be introduced.
Owing to the rapid decomposition of ammonia by high temperatures it is best to
lead the pipe D down the inside from the top of the pot A, but it is evident that a
suitably protected pipe might be led from the outside into the bottom of the pot.
A convenient hoisting apparatus E is arranged above the pot so that the ammonia
pipe and cover can be lifted out and in.
Spare covers without ammonia pipes are provided for closing the pot A when the
ammonia pipe is not in place.
F is an oven or drying chamber in which the raw materials may be dried and
warmed.
The covers are provided with suitable openings through which the fluid inside
can be gauged or sampled. These openings can be closed air-tight by plugs or
covers G.
The pot or crucible H is provided for the final heating of the alkali or alkali and
carbon before they are put in the pot. The alkali, or the mixture of alkali and
carbon to be heated is contained in an inner case I which can be filled on the
ground or at any convenient point and is then hoisted up and slipped into the

page_text: crucible H, from which after heating it is again removed and its hot contents
turned over into the melting pot A.
The heating pot or crucible may be arranged in any other convenient way so as
to carry out the object aimed at.
In carrying out the process in apparatus of this form the charge of dry, hot alkali
and carbon along with a proportion of cyanide is brought into a state of tranquil
fusion in the melting pot A at a suitable temperature. The cover of the pot A is
then quickly removed and the ammonia tube D lowered into its place and the
attached cover firmly secured to the flange of the pot.
Before lowering the ammonia tube into the liquid it is advisable to turn on the
ammonia, otherwise the liquid would be apt to plug the tube and close its
perforations.
The stream of ammonia is bubbled through the liquid mixture in the pot till the
desired percentage of cyanide is reached. This is ascertained by sampling the
liquid by a dipper introduced through one of the openings G in the cover, care
being necessary to avoid oxidation of the cyanide by air.
Fresh portions of alkali and carbon may be added from time to time, till the pot
is filled to its fullest working capacity, or the full charge may be introduced before
the ammonia is turned on.
When the required percentage of cyanide has been reached the ammonia pipe is
withdrawn from the pot, which is immediately closed by one of the close-covers.
The cyanide is then run off into moulds or drums by the upper tap hole a¹. The
portion of cyanide which remains in the pot serves to start the next charge.
When the alkali used is carbonate of potassium I find that the process proceeds
satisfactorily at a temperature somewhat below the melting point of pure carbonate
of sodium, and that I easily obtain a product containing 70 per cent. of cyanide
and upwards, but I do not restrict myself to that or any other precise
temperature.
In running off the cyanide I find it convenient to leave a proportion of the
finished charge in the pot to provide cyanide with which to start the next charge,
and this as above stated can be effected by drawing off the finished charge through
the upper tap hole a¹.
The pot A is provided at its upper end with an exit pipe K through which the
gases from the process are conveyed through suitable scrubbers for the recovery of
such excess of ammonia as may have escaped decomposition in the pot, and of any
volatilized alkaline salts. Or these gases, after the removal of any water they may
contain, may be led through secondary retorts or tubes containing alkalised charcoal
kept at a suitable temperature for the formation of cyanide, the charcoal with
cyanide so obtained being used in making the mixture for the pot. By this means
the waste of either ammonia or alkali is reduced to a minimum.
I
The chamber used for the condensation and deposition of cyanides carried over.
by the gases from the melting pot A may be in the form of a tube or pipe X of any
suitable length, and to which the escape pipe K from each of the melting pots is
connected, a plug or other valve x being provided for cutting off such connection
when the melting pot is open. At one end of pipe or tube X, a pipe Y extends
downwards, so that the cyanide deposited in the tube can be delivered therefrom
into a drum or other receptacle Z when desired. A scraper is preferably provided
within tube X, and when actuated by the handle or rod z¹ (working through a
suitable stuffing box or gland) will carry the deposited cyanide to the end of the
tube at which delivery pipe Y is situated, and cause same to pass into the latter.
The bottom of pipe Y is provided with a slide or other valve ', for closing same
except when it is desired to deliver the cyanide.
A pipe y enables the gases to pass from chamber or tube X either to a second
chamber for further treatment for the recovery of any cyanide still contained in
such gases, or to scrubbers for the recovery of ammonia therefrom.
It will be readily understood that the apparatus for recovering the cyanides
above described is only given as an example of a suitable form of apparatus for such

page_text: purpose, and that any other form of apparatus might be employed which would
enable the cyanides contained in the gases.to be effectually condensed and
deposited.
Fig. 5 of the drawings is a vertical cross section of a vertical retort arranged for
carrying out my process in a more continuous manner.
A is the body of the melting pot which is cast with a solid bottom.
B the furnace and C flues.
L is a central shaft carrying shelves or discs M provided with suitable openings.
N are scrapers fixed to the body of the melting pot and which sweep the shelves
or discs as the latter are turned by the shaft.
O is a hopper with a feeding arrangement for the raw material.
D is the ammonia pipe.
a is the tap hole with plug.
K is the exit pipe for the gases.
P is an opening for the introduction of fresh material into the hopper.
In carrying out my process by this apparatus, the temperature having been raised
to a suitable point, the hopper O is charged with dry material, the ammonia is
turned on through the pipe D, and the shaft L is slowly turned. The mixture of
alkali, cyanide and carbon drops on to the top shelf M when it is met by the up
coming current of gas containing ammonia. The scrapers stir and push forward the
mass and cause it to drop through the perforations in the shelves. As the mixture
drops from shelf to shelf it becomes more fluid and flowing over the surfaces of the
discs or shelves is freely exposed to the ammonia. The apparatus is fed and worked
at such a speed as to ensure that the mixture which collects at the bottom contains
a sufficient percentage of cyanide. The finished product is run off from time to
time by the tap hole a at the bottom.
When is desirable to avoid the use of moving parts within the highly heated
portions of the apparatus the arrangement shown in Fig. 6 may be employed.
The vessel A is set in a brick oven and heated by the furnace B.
The vessel A is fitted with pairs of shelves l, preferably concave and convex, the
concave ones having a hole or holes in the centre, and the convex ones spaces or
holes round the circumference.
The ammonia tube D enters the vessel A at the bottom thereof, as in the arrange-
ment shown in Fig. 5.
H is a crucible in which the fluid mixture of alkali, cyanide and carbon is
prepared. is a plug valve through which the fluid mixture can be gradually run
through the pipe into the top of the vessel A.
The whole apparatus having been brought to a working temperature and the
mixture in crucible H having been brought into a state of tranquil fusion, ammonia
is turned on to the pipe D and a gentle stream of the fluid mixture is allowed to
flow through the pipe into the vessel A, in which it flows down from shelf to
shelf 1, 1, 1, exposing a large surface to the up coming gases and ammonia so that
cyanide is produced. The rate of flow of the mixture is regulated by the condition
of the product which collects in the bottom of the retort, and if need be the product
is treated with a further quantity of ammonia by bubbling, if the percentage of
cyanide produced by flowing over the shelves is not sufficient.
The ammonia is generated in any convenient way but care should be taken to
free it as thoroughly as possible from water vapour. I can to a certain extent use
the volatile alkaloidal bases from crude shale or coal oils, or from peat tar, or from
animal or bone oil instead of ammonia.
The alkalies I prefer to use are the anhydrous carbonates of potassium and
sodium, separately or in mixture, but other anhydrous alkalies may be used. The
carbon may be supplied by charcoal, lamp black, gas black, coke or pitch or any
other convenient source.
By using pitch or coke made from the basic tars or from the crude oils of
shale, coal or peat, I am able to recover a large part of the nitrogen they contain
as cyanide.

page_text: When volatile alkaloidal bases are used as a source of nitrogen it is not necessary
to use so much free carbon in the mixture with alkali, as the decomposition of
these bases produces free carbonaceous matter.
When it is intended to convert the cyanide into ferro-cyanide I may add a
proportion of finely-divided iron to the mixture of alkali, cyanide and carbon.
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 :-
1. The process for the production of cyanides of the fixed alkalies, consisting in
bringing ammonia into intimate contact with a liquid fused mixture of anhydrous
alkali, cyanide and carbon.
2. The process for the production of cyanides of the fixed alkalies, consisting in
bringing the vapours of alkaloidal bases into intimate contact with a liquid fused
mixture of anhydrous alkali, cyanide and carbon.
3. The process for the production of cyanides of the fixed alkalies, consisting in
bringing ammonia into intimate contact with a liquid fused mixture of anhydrous
alkali, cyanide and carbon, the fused cyanide so produced being run or emptied out
directly from the apparatus.
4. The process for the production of cyanides of the fixed alkalies, consisting in
bringing ammonia into intimate contact with a liquid fused mixture of anhydrous
alkali, cyanide and carbon, the cyanide produced being sublimed and obtained as a
sublimate.
5. The apparatus for the production of cyanides of the fixed alkalies consisting
in a melting pot or vessel heated by suitable means and having an open ended or
perforated pipe descending to or entering at or near the bottom thereof, so as to
euable ammonia or the vapours of alkaloidal bases to be distributed by bubbling or
otherwise through the liquid fused mixture contained in the bottom of such melting
pot or vessel, substantially as specified.
6. The apparatus for the production of cyanides of the fixed alkalies consisting
in a melting pot or vessel heated by suitable means and having an open ended or
perforated pipe descending to or entering at or near the bottom thereof, so as to
enable ammonia or the vapours of alkaloidal bases to be delivered to the bottom of
such melting pot or vessel, in combination with a set of perforated shelves arranged
one above the other in the pot or vessel and over and through which a liquid fused
mixture of alkali, cyanide and carbon is caused to flow downwards in succession, and
of a set of stirrers arranged to sweep such shelves, either the shelves or the stirrers
being caused to rotate, substantially as specified, and shown in Fig. 5 of the
drawings.
7. The apparatus for the production of cyanides of the fixed alkalies consisting in
a melting pot or vessel heated by suitable means and having an open ended or
perforated pipe descending to or entering. at or near the bottom thereof, so as to
enable ammonia or the vapours of alkaloidal bases to be delivered to the bottom of
such melting pot or vessel, in combination with a set of pairs of shelves arranged
one above the other within the pot or vessel, one of each pair of the shelves being
perforated or having openings at or near its periphery, while the other one of each
pair of shelves has perforations or openings at or near its centre, substantially as
specified and as shown in Fig. 6 of the drawings.
Dated this 15th day of January 1892.