Improvements in the Manufacture of Sulpho Cyanides, in the Recovery of Bye Products, and in Apparatus therefor.
Year: 1893

page_text: Date of Application, Túth Nov.,
1690
Complete Specification Left, 10th Sept., 1894-Accepted, 13th Oct., 1894
Date of Application, 10th N.,
Complete Specification Left, 10th Sept., 1894-Accepted, 13th Oct., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Sulpho Cyanides, in the
Recovery of Bye Products, and in Apparatus therefor.
We JOHN BROCK of Wellfields Farnworth Widnes in the County of Lancaster
Director of The United Alkali Company Limited and ALBERT EDWARD
HETHERINGTON Ph. D., FERDINAND HURTER Ph. D. and JULIUS RASCHEN
Ph. D. all of Central Laboratory, Widnes aforesaid, Analytical Chemists do
hereby declare the nature of this invention to be as follows:-
This invention is based on the well known reaction between carbon bisulphide
and ammonia which produces successively sulpho carbonate and sulpho cyanide of
ammonium and this said invention has for its object the more economical utilization
of the raw materials employed as well as a more rapid production of cyanides
than hitherto and the recovery of the sulphur and the ammonia which are not
finally contained in the sulpho cyanide.
According to this invention a mixture of bisulphide of carbon, ammonia lime
and water in suitable proportions is agitated in a suitable apparatus and the
mixture is heated gradually to a temperature preferably above 212° Fahrenheit.
The lime is added for the purpose of absorbing sulphuretted hydrogen gas which
would otherwise be evolved and carry away some carbon bisulphide vapours and
ammonia.
It is believed that it will be found best to use for every 100 parts of bisulphide of
carbon from about 33 to 45 parts of ammonia calculated as anhydrous ammonia
180 to 200 parts of slaked lime and sufficient water to permit of proper agitation
of the mixture.
This mixture is agitated and heated in a closed vessel until a sample withdrawn
and tested shows little or no sulpho carbonate. The mixture now consists of
sulpho cyanide of calcium, free ammonia in solution, calcium sulphide partly in
solution but chiefly in suspension, and some lime.
The vessel containing this mixture is then connected with a suitable apparatus
for absorbing ammonia and the boiling of the mixture at atmospheric pressure
and its agitation are continued until the whole or nearly the whole of the ammonia
is driven off, which, after condensation, can be used in a further operation. The
contents of the vessel are then discharged on to a vacuum filter to separate as
completely as possible the solution containing the calcium sulpho cyanide and
soluble sulphide from the insoluble portion.
Carbonic acid gas from any convenient source (such as a lime kiln) is then
forced through the solution for the purpose of decomposing the sulphides,
calcium carbonate being formed and sulphuretted hydrogen set free which may be
collected and utilized in any well known manner.
If calcium sulpho cyanide be the product desired the solution is filtered and
evaporated but should potassium or sodium sulpho cyanide be required there is
added to the solution of calcium sulpho cyanide, freed from sulphides by carbonic

page_text: acid gas, the necessary quantity of the respective carbonate without previous
filtration or cooling during which operation the solution is agitated. Calcium
carbonate and sodium or potassium sulpho cyanide (as the case may be) are
formed the calcium carbonate being separated by filtration and the solution of
sodium or potassium sulpho cyanide being evaporated to dryness or to the point of
crystallisation.
The apparatus used according to this invention is preferably a steam jacketted
cylinder made of cast iron or steel for instance and provided with an agitator and
capable of withstanding considerable pressure. This vessel must also be provided
with apertures (capable of being hermetically closed) respectively for the
admission of the ingredients and for the withdrawal of the finished products, and
also with a pressure gauge, a safety valve and a sampling tap. The top of the
cylinder is connected by means of a pipe and valve with a cooling worm and an
ammonia condensing apparatus.
Or there may be used a steam jacketted revolving cylinder furnished inside
with breakers or buckets and also with the necessary apertures for the admission
and withdrawal of the contents, and with a pressure gauge a safety valve and
connections to a cooling worm and an ammonia condensing apparatus.
Into these cylinders the materials are charged and the agitator is set in
motion. The contents are then gradually heated by slowly admitting steam into
the jacket, to the requisite temperature preferably above 212° F. Should from
any cause the pressure rise too high (such as a stoppage of the agitator or too
slow absorption of sulphuretted hydrogen) the valve of the pipe leading to the
cooling worm and ammonia condenser is opened and both the bisulphide of carbon
and the ammonia gas will be therein condensed and can thus be recovered.
If the agitation be sufficient the pressure does not usually rise to any
considerable extent and in that case the valve of the pipe leading to the cooling
worm and ammonia condenser is not opened until a sample withdrawn shews the
reaction to be completed.
When that operation is finished, the heating is continued so that the excess of
ammonia is distilled off and passes into the cooling worm and from thence into
the condenser. When the liquor is practically free from ammonia it is withdrawn.
and may be treated as hereinbefore described.
Or, carbonic acid gas may be forced from any convenient source (such as a
lime kiln) through the mixture before filtration in a suitable apparatus so as to
decompose all the sulphide of calcium both soluble and insoluble, and utilize the
sulphuretted hydrogen thus produced for the manufacture of sulphur as is well
understood. By this operation the whole of that sulphur which is not contained in
the sulpho cyanides is recovered.
The condensing apparatus may consist of a coil of pipes (of iron for instance)
surrounded by cold water and communicating below with a catch box to collect
any liquids which may have condensed. The gas is conveyed from the catch box
to a condensing apparatus where it comes into intimate contact with a spray of
water, by which the ammonia is absorbed, and recovered.
A tower containing coke or like material may be used with advantage as the
condensing apparatus, and this tower may be fed with water or with the dilute
solutions derived from the washing of the various precipitates obtained in the
process.
Dated the 10th day of November 1893.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.

page_text: Improvements in the Manufacture of Sulpho Cyanides, in the
Recovery of Bye Products, and in Apparatus therefor.
We, JOHN BROCK of Wellfields, Farnworth Widnes, in the County of
Lancaster, Director of The United Alkali Company Limited and ALBERT EDWARD
HETHERINGTON Ph. D., FERDINAND HURTER Ph. D., and JULIUS RASCHEN
Ph. D., all of Central Laboratory, Widnes aforesaid Analytical Chemists 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 is based on the well known reaction between carbon bisulphide
and ammonia, known as Gelis process which produces successively sulphocarbonate
and sulphocyanide of ammonium and this said invention has for its object the more
economical utilization of the raw materials employed as well as a more rapid
production of sulpho cyanides than hitherto and the recovery of the sulphur and
the ammonia which are not finally contained in the sulphocyanide.
According to this invention a mixture of carbon bisulphide, ammonia, lime and
water in the proportions hereinafter stated or thereabouts is agitated in a suitable
apparatus and the mixture is heated gradually to a temperature of 212° Fahrenheit
or preferably above 212° Fahrenheit. The lime forms the base for the sulpho
cyanide and absorbs sulphuretted hydrogen gas which would otherwise be evolved
and carry away some carbon bisulphide vapours and ammonia.
We use for every 100 parts (by weight) of carbon bisulphide at least 33 parts
but preferably 45 parts of ammonia (calculated as anhydrous ammonia) 180 to
200 parts of slaked lime in the form of fine powder and sufficient water to permit
of proper agitation of the mixture. We find a suitable amount of water to be
from 500 to 1000 parts inclusive of that contained in the liquid ammonia.
The proportions of carbon bisulphide and ammonia which we prefer, as above
indicated are such, that for every molecule of CS, there shall be present in the
nixture two molecules of ammonia (NH,). Theoretically one molecule of carbon
bisulphide requires only one molecule of ammonia to furnish the nitrogen needed
for the formation of sulpho-cyanide according to the equation :-
TY
LOND
H. 1 4HU
2 CS₂+ 2 NH, +2 CaH₂O, Oa (ONS), +
2 T
We have found however that this equation does not represent the decomposition
actually taking place, when the ingredients are mixed in these theoretical propor-
tions, since in addition to the sulpho cyanide large quantities of sulpho carbonate
of calcium are formed. In consequence of the well known instability of calcium
sulpho carbonate (which with water readily decomposes into calcium carbonate and
sulphuretted hydrogen) carbon bisulphide is thus lost and the yield of calcium
sulpho cyanide is diminished.
We have found that the formation of calcium sulpho carbonate and the
consequent loss of carbon bisulphide are practically avoided and the yield of
sulpho cyanide thereby proportionately increased by the use of two molecules of
ammonia to every one molecule of carbon bisulphide.
The mixture of carbon bisulphide, ammonia lime and water is agitated and
heated in a closed vessel until a sample withdrawn and tested shews little or no
sulpho-carbonate, as indicated by the absence of the characteristic red coloration
due to sulpho-carbonate. The mixture now consists of calcium sulpho cyanide, in
solution, free ammonia in solution, calcium sulphide partly in solution but chiefly in
suspension and some lime.

page_text: The vessel containing this mixture is then connected with a suitable apparatus
for absorbing ammonia, and the boiling of the mixture (which may be assisted by
the introduction of live steam into the vessel) at atmospheric pressure, and its
agitation are continued until the whole or nearly the whole of the ammonia is
driven off, and it, after condensation, can be used in a further operation. The
contents of the vesse! are then discharged onto a vacuum filter to separate as
completely as possible the solution containing the calcium sulpho-cyanide and
soluble sulphide from the insoluble portion. The precipitate is then washed and
the wash water may be used instead of pure water in the next operation or for
condensing the ammonia carbonic acid gas from any convenient source (such as a
lime kiln) is then forced through the solution for the purpose of decomposing the
sulphides, calcium carbonate being formed and sulphuretted hydrogen set free
which may be collected and utilised in any well known manner.
Or carbonic acid gas may be forced from any convenient source (such as a lime
kiln) through the mixture before filtration in a suitable apparatus so as to
decompose all the calcium sulphide both soluble and insoluble and utilize the
sulphuretted hydrogen thus produced for the manufacture of sulphur, as is well
understood. By this means the whole of that sulphur which is not contained in
the sulpho-cyanides is recovered.
If calcium sulpho cyanide be the product desired the solution is filtered and
evaporated. Should potassium or sodium sulpho cyanide be required there is
added to the solution of calcium sulpho cyanide, freed from sulphides by carbonic
acid
gas, the necessary quantity of the respective carbonate without previous
filtration or cooling during which operation the solution is agitated. Calcium
carbonate and sodium or potassium sulpho cyanide (as the case may be) are formed,
the calcium carbonate being separated by filtration and the solution of sodium
or potassium sulpho cyanide being evaporated to dryness or to the point of
crystallization.
The apparatus used for carrying out this invention is shewn on the accom-
panying drawing.
A is a steam jacketted cylinder made of cast iron or steel for instance, provided
with an agitator B driven through suitable gearing C by an engine D.
The ends of the cylinder are preferably not jacketted, so that the various
apertures and other fittings may be more easily attached. The shaft of the
agitator is supported at one end of the cylinder by the stuffing box through which
it passes and within the cylinder by the bearing bracket Y. At the other end of
the cylinder is fitted a manhole R for purposes of cleaning and repairs. The
cylinder is capable of withstanding a considerable pressure (say 180 to 200 lbs. per
square inch). The cylinder is further provided with several apertures all of them
capable of being hermetically closed by valves taps or lids. E is the inlet pipe
for the ammonia liquor as well as for the carbon bisulphide, this pipe having
communicating with it the pipes with valves for the supply of the ammonia liquor
and the carbon bisulphide. F is an aperture or pipe fitted with an airtight lid or
cover, through, which the sieved lime is introduced.
The vessel or cylinder is first charged with the ammonia liquor and water. The
lid on F is then removed and the sieved lime is thrown in, the agitator having first
been set in motion. In order to avoid a loss of ammonia the pipe F may
advantageously be made to dip into the liquor (or as is shewn in the drawing) a
plate G attached to the top and sides of the cylinder and reaching below the surface
of the liquor (indicated by the dotted line) prevents the escape of ammonia vapours
from the main portion of the cylinder during the operation of charging the lime.
The carbon bisulphide is then allowed to flow in by the opening at E after the lid
en F has been fastened. During the whole operation of charging the vessel.with
the several ingredients the tap H must be open so that the displaced gases may
escape through the ammonia absorbing apparatus. The materials are charged in
the relative proportions hereinbefore given or thereabouts.
When the cylinder has thus been charged all openings and taps are hermetically

page_text: closed, and steam is admitted into the jacket through the opening I the water of
condensation flowing out through the opening K. The agitation must be continued,
so that the lime may be kept in suspension and thus readily absorb the sulphurettet
hydrogen gas generated by the reaction. With a sufficiently rapid agitation and
an ample amount of water the pressure in the vessel as indicated on the pressure
gauge L will not usually rise above 50 lbs. to the square inch. If from any cause,
such as an accidental stoppage of the agitator and consequent slow absorption of
the sulphuretted hydrogen the pressure should rise too high, we provide a safety
valve M so arranged that any vapours escaping may pass into the ammonia
condensing apparatus. If it is desirable to release the pressure, we open the tap H
temporarily to allow some of the gases to escape into the condensing apparatus.
The heating by means of the steam jacket is continued until the temperature
indicated by the thermometer O reaches at least 212° Fahrenheit. If the pressure
is not too high the heating may be accelerated by the admission of live steam into
the interior of the cylinder through the tap P. It is advisable to place a back-
pressure-valve between the tap and the boiler, so that no liquid can flow back into
the boiler.
As the reaction approaches completion the pressure falls and a sample may be
drawn by means of the tap N and tested. When the reaction is complete the
valve H is opened and the charge is boiled by means of live steam (admitted
through the tap P) continuing the agitation so as to expel the ammonia which has
not been changed in making the sulpho cyanide. The ammonia gas escaping
through the tap H is led by the pipe S into the tubular condenser T cold water
entering at U surrounding the tubes and abstracting the heat from the gases within
the tubes, and leaving the apparatus at V. The liquid condensing in the tubes
may be withdrawn by means of the tap W any ammonia vapours which escape
condensation in T pass on to the coke scrubbers X X, where they are absorbed by
a stream of cold water. The ammonia liquors thus recovered are again used in a
future operation.
When the charge is practically free from ammonia it is withdrawn through the
tap Q and may then be treated as herein before described.
Having now particularly described and ascertained the nature of this inveu-
tion and in what manner the same is to be performed we declare that we are
aware of the Specification of Crowther and Rossiter's Patent No. 17846 A.D. 1893
and we wish it to be understood that we make no claim to anything as described
and claimed therein but what we claim is :-
1. The manufacture of sulpho cyanides and the obtainment of bye products by
subjecting the materials herein before mentioned and in, or about, the relative
proportions hereinbefore given, to the operations hereinbefore described.
2. An apparatus arranged or constructed, substantially as hereinbefore described
and shewn in the accompanying drawings for the purpose described.
Dated this 10th day of September 1894.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, Agents.