IMPROVE- THE MANUFACTURE OF CERTAIN CYANOGEN COMPOUNDS AND MENTS IN AMMONIA
Year: 1882

page_text: LETTERS PATENT to Ludwig Mond, of Winnington Hall, Northwich, in the
County of Chester, Manufacturing Chemist, for an Invention of "IMPROVE-
THE MANUFACTURE OF CERTAIN CYANOGEN COMPOUNDS AND
MENTS IN
AMMONIA
"
PROVISIONAL SPECIFICATION left by the said Ludwig Mond at the Office
of the Commissioners of Patents on the 28th January 1882.
LUDWIG MOND of Winnington Hall Northwich in the County of Chestor,
Manufacturing Chemist. "IMPROVEMENTS IN THE MANUFACTURE OF CYANOGEN
COMPOUNDS AND AMMONIA."
'This Invention consists in improvements on the process of obtaining barium
cyanide and ammonia patented by Messrs Margueritte and Sourdeval No. 1027 of
1860 which consists in heating to an elevated temperature barium carbonate or
barium oxide intimately mixed with carbon in an atmosphere of nitrogen whereby
a compound or compounds of barium and cyanogen are formed and after cooling
treating the material by steam at a temperature of from three hundred degrees to
five hundred degrees centigrade whereby ammonia is liberated.
This process
failed to succeed commercially owing among other reasons to the materials being
used in the pulverulent form and being thus apt to cake or choke or cause the gas
to act imperfectly and also owing to the various operations being performed in one
retort which was consequently subjected to frequent and great changes of
temperature causing great waste of fuel and wear and tear.
To obviate these defects I first make my materials into bricks or lumps and
treat them in suitably arranged kilns or ovens or I treat them in retorts or
chambers so arranged that the upper part of them only is heated and then cool
them in a lower part of these retorts or chambers or in a second retort or chamber
connected with the first and subsequently treat the materials by steam in a still
lower part of these retorts or chambers or in a separate apparatus altogether.
In making the bricks or lumps I take the barium carbonate and carbonaceous
matter preferably finely pulverized and if desired by the operator mixed with a
quantity of strontia, magnesia or lime, or their carbonates so as to make them less
fusible as a whole and when well mixed form them into blocks (with pitch as an

page_text: "
agglutinating substance) preferably moulding them hot as is done with "patent
fuel" and preferably heat these blocks in a reducing flame to a degree sufficient to
coke the pitch or still further until a part or all of the barium carbonate is
converted into barium oxide. I prefer to use wood charcoal or coke and pitch for
this purpose say :-32 carbonate of baryte, 8 charcoal, 11 pitch. but can use any
other organic agglutinating substance sufficiently free from inorganic impurities or
I can use a solution of an oxide or an easily decomposable salt of an alkali or
alkaline earth to bind the materials together. If necessary when cold I break
these blocks up to the requisite size say lumps of such size as will pass through a
ring about 3 inches in diameter. Or I mix the carbon and barium carbonate to which
may be added some carbonate of potash or soda, or some other salt or salts of
the alkalies or alkaline earths to render the mass more fusible on the bed of a
furnace or in a revolving furnace in a reducing flame till the carbonate melts and
forms a pasty or viscous mass with the carbon when it is withdrawn cooled and
broken up.
The change to cyanogen compounds can be accomplished in various ways:-
One plan is to treat the materials in a system of chambers kilns or ovens of
convenient shape-preferably kilns of the type known as a continuous kiln
consisting of numerous chambers some of which are being heated while the others
are being cooled, filled or emptied. A chamber being filled it is heated by passing
through it a gas which has been elevated to a high temperature (say 1400 degrees
centigrade) before entering the chamber said gas containing as inuch nitrogen as
possible with the smallest practicablo amount of oxygen, carbonic acid or vapour of
water. Fuel can be economised both in heating and in cooling on the well known
principle used in continuous kilns. When a sufficient amount of cyanogen
compounds has been formed the hot gas is shut off and cool gas of the same or
similar composition is passed through until the temperature is reduced to below
500 degrees centigrade when the supply of gas can be shut off and the materials
- treated with steam to liberate aminonia (which is drawn out by means of an
aspirator and condensed or absorbed as desired); or the current of cold gas is
continued untill the material is sufliciently cool to take it out of the chamber (in
any case below 300° centigrade as at higher temperatures the cyanogen compounds
are largely decomposed on contact with air) It is then lixiviated with water and
the liquors obtained are treated by well known means to obtain cyanogen
compounds or it is treated with steam in a separate apparatus say an iron retort
at a temperature of from 300 degrees to 500 degrees centigrade to produce
ammonia. In place of steam a spray of water or mixture of steam and water or
of nitrogen and water may be introduced. After this treatment the bricks can be
repeatedly subjected to the same treatment until the carbon is sufficiently exhausted
when they are ground up with fresh carbon and pitch and made into bricks again
or they may be remade after each operation by replacing the carbonaceous materials
consumed. As a source of nitrogen the gases are very suitable which escape from
the absorbing plant of the ammonia soda manufacture. Theso gases may be
heated to the required temperature by any known means preferably a Siemen's
regenerator. Or I use the hot gases produced by the combustion of coal or coko
with a minimum quantity of air so that they contain as little carbonic acid
and vapour of water as possible. These gases may be obtained at the high
temperature required by further heating them in a regenerator or other heating
apparatus or preferably by previously heating the air used in the combustion of
the fuel. When using the last named gases it becomes necessary to cool the gases
after leaving the last kiln used at the time for heating the material by passing
them under boilers, pans et cetera or through a scrubber down which water is
running before they are introduced into the kiln or kilns in which at the time the
material is cooling. The gases leaving the kilns which consist largely of carbonic
oxide can be used as a source of heat say for heating the air raising the steam and
heating the ammonia generating apparatus in the process under consideration or
for any other purpose.

page_text: In some cases it may be found convenient to use the hot gases obtained from
gas producers, as described for heating the material and to effect the cooling by
the gases obtained from the manufacture of bicarbonate of soda by the ammonia
process or by any other gases of the required composition which may be available.
A modification of this plan useful especially in small works consists in forming the
barium cyanide in a retort or chamber the upper part of which is heated externally
while the lower or middle part is not exposed to the hent but on the contrary is
cooled preferably both externally and internally as will be hereinafter described.
The material is cooled in its passage through the middle part and near the bottom
is exposed to the action of steam. Or the material is carried when sufficiently
cooled to an independent apparatus to be steamed.
The retorts are preferably vertical clay cliptical retorts rising in four rows
through a chamber heated by a series of hot gas and air jets, the hot gases passing
up round the two nearest rows of retorts and down round the outer row then out
by orifices into the return flue. The cooling chambers below are preferably iron
continuations of the clay retorts. In some cases hot gases rich in nitrogen and
free of deleterious ingredients as mentioned above are introduced near the
junction of the iron and clay retorts. This increases the yield but involves more
cooling space. Or instead of this cold gases of the required composition before
mentioned are introduced near the bottom of the cooling space, and rising up are
heated by the descending materials and cooling the latter until they enter the clay
retort very hot.
The materials cooled to 400 or 500 degrees centigrade can be treated with steam
in the lowest part of the iron chamber or retort preferably in a part shut off from
the rest by a damper or cock, or they can be cooled to 300 degrees and removed
to an independent apparatus heated again to about 300 or 500 degrees and steamed
to produce ammonia. The gases leaving the top of these retorta can also be used
as fuel
Throughout this Specification I have only spoken of carbonate of barium, this
can however be partially or wholly replaced by the carbonates of potassium and
sodium the proportion of carbon being increased at the same time as required.
The results obtained are however less favourable,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Ludwig Mond in the Great Seal Patent Office on the 28th
July 1882.
LUDWIG MOND of Winnington Hall Northwich in the County of Chester,
Manufacturing Chemist. "IMPROVEMENTS IN THE MANUFACTURE OF CERTAIN
CYANOGEN COMPOUNDS AND AMMONIA."
This Invention consists in improvements on the process of obtaining barium
cyanide and ammonia patented by Messrs. Marguerite and Sourdeval in Great
Britain No. 1027 of 1860 which consists in heating barium carbonate or barium
oxide intimately mixed with carbon in an atmosphere of nitrogen to an elevated
temperature whereby a compound or compounds of barium and cyanogen are
formed and then treating the material by steam at a temperature of from three
hundred degrees to five hundred degrees centigrade whereby ammonia is liberated.
This process failed to succeed commercially owing among other reasons to the
materials being used in the pulverulent form and being thus apt to cake or choke
or cause the gas to act imperfectly and also owing to the various operations being
performed in one and the same retort which was consequently subjected to frequent
and great changes of temperature causing great waste of fuel and wear and tear.
Another reason for the failure of previous attempts to work out this process was
that ordinary fuel being largely mixed with the carbonate of baryta, not merely
for the purpose of supplying carbon for forming cyanides but as ordinary fuel for
supplying heat, the inineral constituents of the fuel remained with the baryta
adulterating it and combining with it so that after several repetitions of the
-process-the-bary.ta would become pratically useless.
To obviate these defects I first make my materials into bricks or lumps and
treat them in suitably arranged kilns or ovens or 1 treat them in retorts or chambers
so arranged that the upper part only is heated, and then cool them in a lower part
of these retorts or chambers or in a second retort or chamber connected with tho
first and subsequently treat the materials by steam in a still lower part of these
retorts or chambers.
In making the bricks or lumps, I take the barium carbonate and carbonaceous
matter preferably finely pulverized and if desired by the operator mixed with a
quantity of strontia, magnesia or lime or their carbonates but preferably magnesia
so as to soak up the melting carbonato of barium and make the inaterial less fusible
as a whole.
When mixed i form them into blocks with pitch as an agglutinating
substance preferably moulding them hot as is done with "patent fuel" and
preferably heat these blocks in a reducing flame to a degree sufficient to coke the
pitch or still further until part or all of the barium carbonate is converted into
barium oxide. I use 1st wood charcoal or coke or preferably a carbon made from
oil or pitch containing little or no ash and 2nd pitch for this purpose say
32 carbonate of baryta 8 charcoal 11 pitch, but can use any other organic
agglutinating material sufficiently free from inorganic impurities instead of the
pitch or I can use a solution of an oxide or an easily decomposable salt of an
alkali or alkalino earth to bind the materials together. If necessary when cold I
break these blocks up to requisite size say lumps of such size as will pass through
a ring about three inches in diameter or I make the lumps by mixing carbonaceous
matter and barium carbonate to which may be added some carbonate of potash or
soda, or soine other salt or salts of the alkalies or alkaline carths to render the
mass more fusible on the bed of a furnace preferably a revolving furnace in a
reducing flame till the carbonate melts and forms a pasty or viscous mass with the
carbon, when it is withdrawn cooled and broken up to the required size.
The change to cyanogen compounds can be accomplished in various ways. One

page_text: plan is to pile the materials in chambers, kilns, or ovens of convenient shape
methodically arranged and connected so as to form a continuous kiln consisting of
numerous chambers-As this type of kiln of which I cite the Hofinann kiln as an
example is well known and none of my improvements relate to the form of kiln
itself. I omit Drawings of this kind of kiln in which the gases or products of
combustion used in heating, converting, or cooling the products in one chamber are
made to do duty in the next and each chamber in succession becomes the first in
the series is filled, heated by hot nitrogenous gases or products of combustion from
the chamber previously filled until in time the material is converted and cooled
and the chamber now the last in the series is shut off emptiod, refilled, and again
heads the series. A chamber being filled with fresh material it is heated by passing
through it the gases from the last chamber previously filled so as to raise the
temperature as high as possible by what would otherwise be waste heat. It is then
heated further by passing through it a gas which has been elevated to a very high
temperature (say 1400 degrees, centigrade) before entering the chamber said gas
containing as much nitrogen as possible with the smallest practicable amount of
oxygen carbonic acid or vapour of water. When by this treatment a sufficient
amount of cyanogen compounds has been formed the hot gas is shut off and a
current of cool gas as free as possible from oxygen, carbonic acid and vapour of
water is passed through the chamber to cool the material. When the material has
been cooled to 500 degrees centigrade the current of cool gas may be stopped and
steam passed into the kiln to liberate ammonia which is drawn out by means of
an aspirator and absorbed in any known manner, or the current of cool gas is
continued until the material is sufficiently cooled to take it out of the chamber (in
any case below 300 degrees centigrade as at higher temperatures the cyanogen
compounds are largely decomposed in contact with air). It is then lixiviated with
water and the liquors obtained are treated by well known means to obtain
cyanogen compounds or it is removed to a separate apparatus say an iron retort
and treated with steam at a temperature of from 300 degrees to 500 degrees
centigrade to produce ammonia. In place of steam a spray of water or mixture
of steam and water or of nitrogen and water may be used. After this treatment
the bricks can be repeatedly subjected to the saine treatment until the carbon is
sufficiently exhausted when they are ground up with fresh carbon and pitch and
made into bricks again or they may be remade after each operation by replacing
the carbonaceous materials consumed. The hot gases employed in the formation
of cyanogen compounds may be obtained at the required temperature by passing
the gases which have been used in cooling the hot material in the chambers
serving at the time for cooling through a regenerator or other suitable heating
apparatus placed conveniently below or besides the kiln so that these gases can be
taken through it on their way from the last cooling chamber to the first converting
chamber; or these hot gases may be obtained in a more direct way by the
combustion of fuel with a minimum quantity of previously heated air in a suitably
constructed fireplace or furnace, say a gas-generator supplied with a hot blast of
300 to 400 degrees centigrade.
When these last named gases are used for producing the cyanide it will be
convenient to use for the purpose of cooling the gases emanating from the chamber
last filled with fresh bricks or lumps; if not cold enough from the contact with
the fresh material these gases may be further cooled by passing them under boilers,
pans, through scrubbers or in any other way before entering the chambers used at
the time for cooling. Any other gases of the required composition will however
answer our purpose, notably the waste gases from several well known chemical
processes such as the manufacture of soda by the ammonia process et cetera
et cetera.
The gases which finally leave the kila consist largely of carbonic oxide and can
be used as a source of heat say for heating the air, raising the steam and heating
the aminonia generating apparatus in the process under consideration or for any
other purpose.

page_text: A modification of this plan useful especially in small works, consists in forming
the barium cyanide in a retort or chamber the upper part of which is heated
externally while the middle part is not exposed to the heat but on the contrary is
cooled preferably both externally and internally as will be hereafter described.
The material is cooled in its passage through the middle part and in the bottom
part of the retort it is exposed to the action of steam.
This system and apparatus can be best described by aid of the accompanying
Drawings in which Fig. 1 shows a sectional plan through W X of Fig: 2, Fig. 2 a
vertical section through Z Y of the plan.
A. A are clay retorts set in four rows in heating chamber B., A' upper
continuation of same. C. C. are the entrance holes for the gas and air preferably
brought from a Siemens regenerator. D D diaphragms or partitions of fire clay
placed between each pair of rows of retorts to force the products of combustion to
ascend round one row of retorts and descend round the other to the exit holes.
E. E exit holes carrying the products of combustion back to regenerator. HH are
the lower portion of the retort A preferably made of iron which can be surrounded
by water or cooled by a blast of air or spray from roses T, T. placed in any
convenient position as found. most convenient I is the pipe through which cold
gases rich in nitrogen are passed into the cooling part of the retort or chamber,
Jis a stopcock and K entrance for steam-L continuation of retort or chamber H
below the stop cock for forming aminonia. M escape for ammonia PQ are the
flues supplying gas and air respectively from the regenerator, R. the exit fluo
carrying the waste gases back to the regenerator, S doors of retort-The mode of
action is as follows:-The retorts or chambers being nearly filled with blocks
which have already partly undergone the cyanide forming process the upper
portions A are filled with fresh briquettes of barium carbonate or oxide and
carbon-The heat in the heating chambers A is maintained to from 1100 to 1400
degrees centigrade, and nitrogenous gases as already described are passed through
entrances II into the chambers H H. As the briquettes in A get hot the nitrogen
reacts upon them and cyanogen compounds are-formed. From time to time
material is abstracted from the bottom of chamber H and fresh material inserted
at A¹.
In its passage through the chamber H the material is cooled so as to arrive at
the stop cock J with a temperature of about 500 degrees centigrade a portion at
this temperature is passed into chamber L. The cock J being shut steam is passed
in through orifice K. This steam should be of less pressure than the nitrogen
entering at I as it is very undesirable that the steam should rise up among the
hot material past the stop cock J which it will be very difficult to keep perfectly
tight.
The steam is passed downward through the materials and the ammonia formed
leaves by orifice M. When ammonia ceases to be formed the steam is shut off
and that portion of the materials hitherto exposed to the action of the steam is
withdrawn-The stop cock is then opened and the material allowed to descend to
fill the void, a fresh charge is inserted at the top of A¹ and the operation goes on
as before.
"
With regard to the foregoing I would remark that when cold nitrogen is
introduced at I it rises up among the hot material cooling the latter and being
heated in its turn till as it enters A it is very hot thus economising fuel on the
principle of the continuous kiln recommended for working on a large scale.
Throughout this Specification I have only spoken of barium-The Invention is
however also applicable with littlo modification if potassium or sodium be used
instead of barium and possibly at extremely high temperatures some of the other
alkaline earths might be substituted for barium.
Having now described my Invention and the best modes known to me of
carrying it into effect I claim as the Invention to be protected under the Letters
Patent :-
1st. In the manufacture of cyanogen compounds of barium or of ammonia there-

page_text: from, the preliminary heating of the mixture of barium carbonate or oxide and
carbon in a reducing flame until they form a pasty mass, and the breaking up of
the mass after cooling into lumps for the formation of cyanogen compounds by
contact with nitrogen at an elevated temperature.
2nd. The improvement in the manufacture of cyanogen compounds by means of
barium salts or oxido and carbon which consists in cooling the hot cyanogen
compounds by passing through them nitrogenous gases as free as possible from
oxygen, carbonic acid and vapour of water.
3rd. The improvements in the manufacture of cyanogen compounds by means of
barium salts or oxide and carbon which consists in treating the barium salt
and carbon at the temperature required to form cyanogen compounds with the
nitrogenous gases already heated by their passage through hot cyanogen compounds
from a previous operation.
4th. The application of the hot nitrogenous gases obtained by burning coal or
coke with hot air in such quantity as to produce gases practically free from
carbonic acid and vapour of water, in the manufacture of cyanogen compounds or
of ammonia by means of barium salts or oxide and carbon.
5th. The manufacture of cyanogen compounds or of ammonia from barium salts
or oxide and carbon by treatment with nitrogenous gases practically free from
carbonic acid and other deletereous ingredients in a retort apparatus substantially
as described and illustrated in the Drawings, or in a kiln, substantially as set
forth.
In witness whereof I the said Ludwig Mond have hereunto set my hand
and seal this Twenty second day of July in the year of our Lord One
thousand eight hundred and eighty two.
Witness,
WP. THOMPSON,
Patent Agent,
Liverpool and London.
LUDWIG MOND. (L.S.)