IMPROVEMENTS IN THE MANUFACTURE OF AMMONIA AND ITS SALTS, AND IN THE APPARATUS EMPLOYED FOR THIS MANUFACTURE
Year: 1879

page_text: LETTERS PATENT to George Neilson Tucker, of 79, Mark Lane, in the City of
London, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF
AMMONIA AND ITS SALTS, AND IN THE APPARATUS EMPLOYED FOR THIS
MANUFACTURE." A communication from abroad by Nicolas Basset, Chemist,
Paris, France.
Sealed the 6th January 1880, and dated the 24th October 1879.
PROVISIONAL SPECIFICATION left by the said George Neilson Tucker at
the Office of the Commissioners of Patents on the 24th October 1879.
GEORGE NEILSON TUCKER, of 79, Mark Lane, in the City of London. "IMPROVE-
MENTS IN THE MANUFACTURE OF AMMONIA AND ITS SALTS, AND IN THE APPARATUS
EMPLOYED FOR THIS MANUFACTURE." A communication from abroad by Nicolas
Basset, Chemist, Paris, France.
This Invention consists in an improved chemical process, and in special arrange-
ments of apparatus to be employed in the manufacture of ammonia and its salts.
The improved process consists essentially in the production of azoture of boron
(a compound of nitrogen and boron) either alone or in conjunction or mixture with
other azotures (or compounds of nitrogen with various bases), cyanides or cyanates,
whether by acting on the amorphous boron only, or on any boride, such as the
alkaline borides, the alkaline-earthy borides, the borides of magnesium, calcium,
barium, aluminium, manganese, antimony, iron, titanium, silicon. The combination
of atmospheric nitrogen with amorphous boron, or with the elements of one or more
of the metallic borides before mentioned, is readily effected by the passage of
ordinary air, of nitrogen, or of air burnt and deprived of its oxygen by combustion,
on a mixture of carbon or coke, or carbonizable organic substances, with an alkaline
borate, or with a borate of one or more of the before mentioned metals, with an
addition of alkali or of alkaline carbonate, or also with boracic acid with the
addition of alkali, or alkaline carbonate and one or more oxides or carbonates, or
one or more decomposable salts of one or more of the aforesaid metals. The object
of this mixture is to bring about the reduction of the alkaline element by the
carbon employed, in order that the alkaline metal in the nascent state may act as
a reducing agent, and concurrently with the carbon on the boracic acid alone, or on
Dminn 21

page_text: this acid and the metallic compounds present. This reaction necessitates the
employment of a red heat. The azoture of boron (Bo. Az.) having been formed, or
the double or multiple azotures composed of one or more metals, of boron and
nitrogen, give ammonia, by the passage of a current of steam, from a dull red to
an ordinary red heat. The operation may also be effected by causing a simul-
taneous current of ordinary air, burnt air, or nitrogen and steam to pass through
the mixtures. The ammoniacal product is purified, condensed, dissolved in water,
or transformed into a salt by the employment of a suitable acid.
The producing apparatus consists of vertical retorts of cast iron, or of fire clay,
rendered impermeable to gases and capable of being hermetically closed, into which
the mixture of the reducing bodies and of the reducible bodies before mentioned
are introduced. After closing the charging aperture the retorts are heated to a red
heat, and then a current of air, burnt air, or nitrogen is made to pass through the
retort at the same time with a current of steam, or the operation may be carried on,
first, by the aid of air, burnt air, or nitrogen and afterwards with a current of
steam, according to whether it is desired to decompose the boro-metallic azotures as
soon as they are formed or to produce them in the retorts before decomposing
them by means of nascent hydrogen arising from steam reduced by carbon and the
other reducing agents present.
In connection with the producing apparatus vessels are arranged for the purpose
of purifying the ammoniacal gas by the action of milk of lime, to condense, dissolve,
and transform it into carbonate, sulphate, or other salt; evaporating vessels for the
concentration of the salts by waste heat; pumps and vessels for utilizing the
carbonic acid of the gases of combustion and for separating from it the nitrogen
which has to serve to form the azotures in such manner that this Invention
comprises not only the production of ammonia by azoture of boron or a double
azoture of boron and another base, or by a multiple azoture of boron and various
other bases, but also the complete organization for a manufacturing plant.
The bases of operation on which the improved process is organized are as
follows:-
It is known that amorphous boron at a red heat combines with nitrogen so as to
form an azoture of boron (Bo. Az.), and that this azoture furnishes ammonia
abundantly by means of a current of steam at red heat. This azoture Bo. Az. has, on
analysis, given 51.124 of nitrogen to 100 parts in weight, which corresponds to
68.15 of anhydrous ammonia. Thus, this azoture is that which gives the most
considerable proportion of ammonia, but the processes hitherto known for the
preparation of amorphous boron and azoture of boron cannot lead to a manu-
facturing result, and the present Invention has for object to supplement this
requirement. When boracic acid and borates are mixed with a sufficient quantity
of alkali, in presence of carbon, at a red heat, the alkalis and metallic oxides are
reduced to the nascent metallic state, and the alkaline metal, reacting on the free
or combined boracic acid sets the boron free in the nascent state, in which this
metalloid readily combines with the metals present, and with nitrogen. The simple,
double, or multiple azotures very readily give up their nitrogen in the state of
ammonia by the action of nascent hydrogen obtained from steam or from an
alkaline hydrate.
In accordance with these bases, charcoal, coke, or a carbonizable or carbonized
substance is taken, and this substance is subjected to the action of a solution
composed of 100 parts of water, 10 to 20 parts of boracic acid, and a proportion of
alkali (potash or soda), or of alkaline carbonate corresponding to 2 chemical
equivalents. For greater rapidity this solution must be employed warm, although
the operation may be conducted with it at the ordinary temperature. A solution
of 20 to 40 parts of ordinary borax and 1 equivalent of alkali or alkaline carbonate
in 100 parts of water may also be employed in a more convenient manner. It is
still better that the solutions be warm on account of the low solubility of the
boracic acid or borax. When the carbon employed, coke for example, is well
saturated with the solution it is drained off, then mixed with magnesia, carbonated

page_text: or not, lime or chalk, carbonate of baryta, alumina, an oxide of manganese or of
antimony, or of iron, or of titanated iron, or with silica, or with the borate of one
of these metals, in such manner as to dry the surface by covering it with a layer of
one of the metallic substances mentioned, employed in the state of oxide, carbonate
or borate.
The carbon or carbonaceous substance thus prepared is introduced into the
retort, the charging and discharging apertures of which are closed, and the
temperature brought to a red heat. A current of nitrogen is then caused to pass
into the lower part of the retort. The gases arising therefrom escape by the tube
at the top. After an hour and a half or two hours of action, that is to say, after a
time sufficient for the reduction of the oxidated compounds and the combination of
the nitrogen, the current of this latter gas is suspended and a current of steam is
substituted for it, which becomes decomposed in the presence of the carbon and
metals and gives nascent hydrogen, which carries away the nitrogen in the state of
ammonia, and which is collected under known conditions realized by the apparatus
hereinafter described.
Action may also be effected differently, and a current of air or nitrogen and
steam in the proportion of 3 volumes of steam to one volume of nitrogen be all at
once introduced into the retort heated to a red heat and ammonia is obtained
which is collected in the same manner.
The metals most advantageously employed in the form of borates, oxides, or
carbonates to cover or coat the carbon or coke saturated with alkali or alkaline
carbonate, with boracic acid or borax and form multiple borides, are those which
most readily take up nitrogen and have been previously mentioned. Amongst
them, magnesium, barium, manganese, titanated iron are those to be preferred.
By this process the metallic residues composing the ashes are not lost, and are
constantly re-used without the necessity of habitually adding new elements other
than the carbon which has been burnt and which has to be replaced. The ashes
lixiviated by heat give the alkaline-boracic solution useful for the impregnation of
the fresh carbon, and the dried insoluble residues serve to cover or coat this carbon
after draining the same. The ammoniacal salts obtained and the ammonia are
very pure, free from arsenic, sulpho-cyanides and sundry other impurities, providing
operations are carried out in the manner hereinafter set forth in the description,
and the improved apparatus which forms a part of the present Invention employed.
In order to avoid useless repetition, and to facilitate the description of the
apparatus, I will refer to some of the parts by numbers and letters.
The producing apparatus is formed either of cast iron or of unpermeabilized fire
clay retorts placed vertically in a special furnace. A fixed part at the lower part
of the retort is provided with a grate for the passage of the ashes, and with an
enclosed end with door, set in the masonry of the furnace. This part is more
advantageously made of cast iron. The body of the retort is of cast iron or fire
clay, and is placed vertically on the lower part so as to make a tight joint by means
of asbestos packing arranged in a groove formed in one of the parts.
The joint is made by the weight of the body of the retort. In the same way
another part which forms a cover is placed on the top of the aforesaid body, and
makes a tight joint therewith. The upper closed end is arranged similarly to the
lower one, and the upper part is advantageously made of cast iron.
At the lower part, the tube, which conducts air or nitrogen and steam into the
incandescent substance, penetrates to the centre of the retort. This tube, a straight
portion of which is set in the masonry, is directed into the retort by a bend, and
above a given line it is pierced with oblique openings from above downwards, by
which the inlet gases are forced to disseminate in the mass of the substance, and to
produce the maximum effect. On the outside, this tube communicates with a
metallic mixing box, into which the air or the nitrogen coming from the supply
tube enters by a cock. The steam coming from the supply tube enters the mixing
box through a suitable cock.
At the upper part of the retort the cover is lengthened into a chimney, from

page_text: which passes an oblique pipe extending from below upwards for the outlet of the
gases produced, which are conducted through a valve to a collecting pipe which is
in connection with the general collector, passing thence to a tube which is in
connection with the rest of the apparatus.
The method of closing the upper and lower ends of the retort is as follows:-
A metallic plate held in position by a hinge has a projection to take into a groove
in the upper or lower part of the body of the retort, and the contact of the same is
effected by the pressure of a screw. There are three of these screws at each door,
and the hinge forms the fourth side. At the bottom of each groove a hermetically
tight joint is made with a band of asbestos by the pressure thereon.
Any desired number of this kind of retort is placed in a special furnace. The
air entering by the ash pits passes through the fuel in the furnaces, where it
becomes changed to a mixture of carbonic acid, oxide of carbon, and nitrogen. The
hot gases of combustion ascend through inclined flues against the fire bridge and
pass into a space in which a retort is mounted.
They are in some measure drawn through small openings in the upper part of
such spaces, but the greater portion is drawn through openings at the lower part
thereof. They then pass into other spaces in which other retorts are fixed, which
spaces they fill; they then pass through the openings at the upper part of such
spaces into flues which conduct them to the draught chimney. This arrangement
causes the action of the heat to be regulated, but this regularity is still further
insured by the heating chambers, their purpose being to store up the caloric in the
greatest possible proportion. To this end the brick walls of these chambers are
pierced with openings arranged in zigzag direction, the hot air of the spaces
occupied by the retorts passes into them, bringing these walls to a red heat, and
this temperature is kept constant by reason of the continuity of the current and
the low conductibility of the material,
The other parts of the apparatus are arranged so as to be in connection with the
furnaces containing the retorts. The resulting gases which pass out of the retort
through the outlet tube (l), valve (m), and collector (n), pass into another collector (u),
thence into a tube (v), and through another valve (m) into a closed vessel (19)
which contains milk of lime for retaining the carbonic acid, the hydro sulphuric
acid, the empyreumatic and tarry products. The vessel has no particular features
of novelty, and the arrangements which it presents are well known in chemical
industries. Thence the gas already purified passes into a close washer (20), where
it is washed by means of water only, then through another valve (m) into another
washer (21) also close, and containing water and a little lime. When the spaces to
be passed through are somewhat long, it may be advantageous to place a suction
and force pump in front of the last mentioned washer (21). On the other hand, if
the mixtures adopted for the work of the retorts contain substances that may be
partially carried away by the current, it is prudent to arrange the water washer (20)
in the place of the lime vessel (19), and vice versa, in order that these substances
may be prevented from passing away at the first. On leaving the lime washer (21)
the ammoniacal gas mixed only with a little water passes into a condenser (22), and
the liquid product is delivered into a receiver (23) through a cock (r, r¹) and
pipe (s, s,) the cock (r, 7, leading to close water vessels 14, 15) remaining closed.
The gaseous non condensed portion is dissolved according to the ordinary method
of manufacture, in water placed in a number of receivers (24, 24', 24¹¹) provided
with safety funnel tubes.
In connection with the last of these receivers (2411) a dip tube (s, 8,1111) carries
the undissolved gas into an acid solution, or into a decomposable saline solution.
From time to time the liquid ammonia is drawn off from the first of such
receivers (23), and in the same manner the liquid is collected from the other
receivers (24), when it is sufficiently concentrated.
When instead of preparing liquid ammonia, it is desired to produce ammoniacal
salts, and particularly sulphate, the operation is performed in a different way,
namely: In connection with the condenser (22) the cock (r, ',) leading to the

page_text: receivers is closed, the cock (r, 7,) is opened, and the liquid or gaseous products pass
through a tube (o, o,) and cock (p, p.) bubbling through the water contained in the
close vessel (14).
According to the requirements of the case, water or a saline solution to be
concentrated, is placed in an evaporating vessel (10), and in a refrigerator (11). A
pump (12) is put in motion when the furnace is heated to a red heat. Immediately
that the gascous current (the product of combustion), composed of carbonic acid,
carbonic oxide, and nitrogen, is drawn from the flue leading to the draught chimney
through a tube (g), it passes through another tube (a) into the tubes (w) of the
evaporating vessel (10), to the liquid of which it gives up a portion of its heat,
then through a tube (y) into the refrigerator (11), from which it is taken by the
pump (12) and conveyed by bubbling into a water washer receiver (13), from which
a tube (a, a,) conveys it into the vessel (14) through a cock (b, b,) by means of a
dip tube. On the contact of the ammoniacal liquid and ammoniacal gas carried
through a cock (p, p,) coming from the condenser (22) through a pipe (o, o,) this
gaseous current gives up its carbonic acid to the ammonia which passes into the
carbonated state.
The nitrogen, carbonic oxide, and a small proportion of ammoniacal product,
carried along or escaping the reaction, passes out through a pipe (d, d,) and is
conducted by a pipe (m, m,) into a close vessel (16) which contains an acid solution
or a decomposable saline solution for retaining the ammonia.
The nitrogen gas
purified from the carbonic acid, and retaining only carbonic oxide, passes through a
pipe (m, n) into the washer receiver (17) provided with a safety valve. From that
vessel a cock directs it into a tube (a, z,) towards the distributing tube (p), which
furnishes it to the mixing boxes (o) for the formation of azotures in the retorts.
When the ammoniacal solution of the vessel (14) is well carbonated, the work is
transferred to another similar vessel (15) simply by the turning of cocks. The
liquid of vessel (14), drawn off through a cock (f, f) passes by a tube (h, h,) into a
vat (25) which contains roughly pulverized gypsum. On contact with sulphate of
lime the carbonate of ammonia changes to sulphate, and carbonate of lime is formed.
The reaction is completed in other vats (25' and' 25") where the liquid passes
through syphoidal tubes (j, j).
The sulphate solution is collected at the outlet (1, 1) of the last mentioned vat,
and is conveyed to the refrigerator (11), and to the evaporating vessel (10), for
concentration. Crystallization is effected in the ordinary manner, and the other
salts are prepared by known means.
To avoid useless stoppages and loss of time, parts 10, 11, 12, 13, 14, 19, and 20
of the apparatus are in duplicate, so that the two sets 10, 11, 12, 13, may be worked.
at the same time, and the vessels 14, 15, 19, and 20 alternatively.
By the combination of these arrangements, considerable advantages are obtained
in the matter of economy.
The waste heat is utilized for the concentration of the saline liquids in the
evaporator (10), the purification of the nitrogen in the various vessels 14, 15, and 16
allows of the transformation free from cost of the ammoniacal product into carbonate,
which is the condition of the decomposition of gypsuin, and avoids the expenditure
in sulphuric acid for the formation of sulphate, which, by this fact itself, is free
from arsenic. And the operation is rendered more profitable by the employment of
nitrogen instead of air, the current being less destructive to the carbon in the
retorts. The method of working for liquid ammonia is very simple. Preparation
of alkaline boracic carbon, dried and coated by the aid of one of the oxides,
carbonates, or borates mentioned. The introduction of this carbon into the retorts
up to a little below the outlet tube (1). Hermetical closing of the covers. Elevation
of the temperature up to a red heat. Water having been caused to arrive at the
line of level in the vessels 10, 10, 11, 111, 13, 13'; milk of lime in 19, 191, 14, 15,
and 21, water in 20, 21, and 22; acidulated water, or a decomposable saline solution
in 16 and 241, and water having been introduced up to the proper level in the
vessels 24, 241, and 241, the valves (m) are opened to the outlet of the retorts

page_text: before the vessels 19, 20, and 21, the set 19', 20¹, remaining closed. The cock (7, r¹)
is opened, but the cock (r, r,) is closed.
The cocks (b, b,) and (b, b¹) on 14 are also opened. When the fire is well alight,
so that the retorts begin to get red, the pumps 12 and 12' are set to work. The hot
gases pass into 10, 101, 11, 111, 12, 121, 13, 131, then into vessel 14, where they lose
their carbonic acid on contact with the milk of lime, and they pass through the
vessel 16 and pipe (n, n,) into the reservoir 17. When the retorts are quite red,
the substance in the retorts is acted on, either by causing to pass successively a
current of nitrogen, coming from the reservoir 17, through pipes az, u, p, r, and
mixing box o, then a current of steam through 8, r, and mixing box o, or by the
simultaneous introduction of nitrogen and steam. The ammoniacal product is
purified in 19, 20, 21, condensed in 22, and then passed into the receiver 23.
The residue is dissolved in the receivers 24, 241, and 24. When the lime of vessels
19 and 14 is exhausted, the current of the products is made to pass through vessels
19 and 20¹, and that of the burnt air through vessel 15, whilst the renewal of the
lime for purification is being effected in 19 and 14. About once a day the working
of each retort is stopped successively for some minutes, for the purpose of opening
the lower door K, and causing the ashes to fall down which are collected; the door
is again shut and the upper one opened to replace with prepared carbon that which
has been consumed. After which the upper door is again closed, and the working
continues. To stop a retort, an air-cock on the outlet tube between and m is
opened, and the cocks r and r¹, and the valve m, are closed. On the renewal of the
work the air-cock is closed, and the cocks and the valve which had been closed are
again opened.
For the production of sulphate of ammonia the method of operation is identical,
only, the vessels 25, 251, and 25" are charged with gypsum; other vessels 10, 10', 11,
and 11 receive the saline solution to be evaporated instead of water; 14 and 15
receive water instead of milk of lime; the cock r, r, is closed, r, r, is opened, and
the ammoniacal product is directed through o, o, and p, p, into the close vessel 14,
instead of being conducted towards the receivers 23 and 24, through the cock ?, 7.
The remainder of the work has been previously described. The vessels of the
apparatus, other than the retorts, are of sheet iron, except the transition vessel 16,
which is of lead, and in duplicate.
The tubes are of iron, as are the valves and cocks; the receiving vessels (23, 24,
24, 24, and 2411) may be made of lead, and all the tubes dipping into sulphuric
liquid are also of lead.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Neilson Tucker, in the Great Seal Patent Office on the 24th
April 1880.
GEORGE NEILSON TUCKER, of 79, Mark Lane, in the City of London. "IMPROVE-
MENTS IN THE MANUFACTURE OF AMMONIA AND ITS SALTS, AND IN THE APPARATUS
EMPLOYED FOR THIS MANUFACTURE." A communication from abroad by Nicolas-
Basset, Chemist, Paris, France.
This Invention consists in an improved chemical process, and in special
arrangements of apparatus to be employed in the manufacture of ammonia and its
salts.
The
The improved process consists essentially in the production of azoture (nitride) of
boron (a compound of nitrogen and boron), either alone or in conjunction or mixture
with other azotures (nitrides or compounds of nitrogen with various bases), cyanides
or cyanates, whether by acting on the amorphous boron only, or on any boride,
such as the alkaline borides, the alkaline earthy borides, the borides of magnesium,
calcium, barium, aluminium, manganese, antimony, iron, titanium, silicon.
combination of atmospheric nitrogen with amorphous boron, or with the elements
of one or more of the metallic borides before mentioned, is readily effected by the
passage of ordinary air, of nitrogen, or of air burnt and deprived of its oxygen by
combustion, on a mixture of carbon, or coke or carbonizable organic substances, with
an alkaline borate, or with a borate of one or more of the before mentioned metals,
with an addition of alkali, or of alkaline carbonate, or also with boracic acid with the
addition of alkali, or alkaline carbonate and one or more oxides or carbonates, or
one or more decomposable salts of one or more of the aforesaid metals. The object.
of this mixture is to bring about the reduction of the alkaline element by the.
carbon employed, in order that the alkaline metal, in the nascent state, may act as
a reducing agent, and concurrently with the carbon on the boracic acid alone, or on
this acid and the metallic compounds present. This reaction necessitates the
employment of a red heat. The azoture (nitride) of boron (Bo. Az. or B. N.),
having been formed, or the double or multiple azotures (nitrides) composed of one
or more metals, of boron and nitrogen, give ammonia, by the passage of a current
of steam from a dull red to an ordinary red heat. The operation may also be
effected by causing a simultaneous current of ordinary air, burnt air or nitrogen
and steam to pass through the mixtures. The ammoniacal product is purified,
condensed, dissolved in water, or transformed into a salt. by the employment of a
suitable acid.
The producing apparatus consists of vertical retorts of cast iron, or of fireclay
rendered impermeable to gases, and capable of being hermetically closed, into which
the mixture of the reducing bodies, and of the reducible bodies before mentioned
are introduced.
After closing the charging aperture, the retorts are heated to a' red heat, and
then a current of air, burnt air, or nitrogen, is made to pass through the retort at
the same time with a current of steam, or the operation may be carried on first by
the aid of air, burnt air, or nitrogen, and afterwards with a current of steam,
according to whether it is desired to decompose the boro-metallic ozotures (nitrides)
as soon as they are formed, or to produce them in the retorts before decomposing
them by means of nascent hydrogen arising from steam, reduced by carbon and the
other reducing agents present.
In connection with the producing apparatus, vessels are arranged for the purpose
of purifying the ammoniacal gas by the action of milk of lime, to condense, dissolve,
and transform it into carbonate, sulphate, or other salt; evaporating vessels for the
concentration of the salts by waste heat; pumps and vessels for utilizing the carbonic
acid of the gases of combustion, and for separating from it the nitrogen which has.

page_text: to serve to form the azotures (nitrides) in such manner that this Invention comprises
not only the production of ammonia by azoture (nitride) of boron or a double azoture
(nitride) of boron and another base, or by a multiple azoture (nitride) of boron, and
various other bases, but also the complete organization for a manufacturing
plant..
The bases of operation on which the improved process is organized are as
follows:-
It is known that amorphous boron at a red heat combines with nitrogen so as to
form an azoture (nitride) of boron Bo. Az. (B. N.), and that this azoture (nitride)
furnishes ammonia abundantly by means of a current of steam at red heat. This
azoture (nitride) Bo. Az. (B. Ñ.) has, on analysis, given 51·124 of nitrogen to 100
parts in weight, which corresponds to 68.15 of anhydrous ammonia. Thus, this
azoture (nitride) is that which gives the most considerable proportion of ammonia,
but the processes hitherto known for the preparation of amorphous boron and
azoture (nitride) of boron cannot lead to a manufacturing result, and the present
Invention has for object to supplement this requirement. When boracic acid and
borates are mixed with a sufficient quantity of alkali, presence of carbon at a red
heat, the alkalis and metallic oxides are reduced to the nascent metallic state, and
the alkaline metal reacting on the free or combined boracic acid sets the boron free
in the nascent state in which this metalloid readily combines with the metals
present, and with nitrogen.
The simple, double, or multiple azotures (nitrides) very readily give up their
nitrogen in the state of ammonia by the action of nascent hydrogen obtained from
steam or from an alkaline hydrate.
In accordance with these bases, charcoal, coke or a carbonizable or carbonized
substance is taken, and this substance is subjected to the action of a solution
composed of 100 parts of water, 10 to 20 parts of boracic acid, and a proportion of
alkali (potash or soda), or of alkaline carbonate corresponding to 2 chemical
equivalents.
For greater rapidity, this solution must be employed warm, although the operation
may be conducted with it at the ordinary temperature. A solution of 20 to 40
parts of ordinary borax, and 1 equivalent of alkali or alkaline carbonate in 100
parts of water may also be employed in a more convenient manner.
It is still better that the solutions be warm on account of the low solubility of
the boracic acid or borax. When the carbon employed, coke for example, is well
saturated with the solution it is drained off, then mixed with magnesia, carbonated
or not, lime or chalk, carbonate of baryta, alumina, an oxide of manganese, or of
antimony, or of iron, or of titanated iron, or with silica, or with the borate of one
of these metals, in such manner as to dry the surface by covering it with a layer of
one of the metallic substances mentioned, employed in the state of oxide, carbonate,
or borate.
The carbon or carbonaceous substance thus prepared is introduced into the retort,
the charging and discharging aperatures of which are closed, and the temperature
brought to a red heat. A current of nitrogen is then caused to pass into the lower
part of the retort. The gases arising therefrom escape by the tube at the top.
After an hour and a half or two hours of action, that is to say, after a time
sufficient for the reduction of the oxidated compounds and the combination of the
nitrogen, the current of this latter gas is suspended, and a current of steam is
substituted for it, which becomes decomposed in the presence of the carbon and
metals, and gives nascent hydrogen, which carries away the nitrogen in the state
of ammonia, and which is collected under known conditions realized by the
apparatus hereinafter described. Action may also be effected differently, and a
current of air or nitrogen and steam in the proportion of 3 volumes of steam to
1 volume of nitrogen be all at once introduced into the retort heated to a red heat,
and ammonia is obtained which is collected in the same manner.
The metals most advantageously employed in the form of borates, oxides, or
carbonates to cover or coat the carbon or coke saturated with alkali or alkaline

page_text: carbonate, with boracic acid or borax and form multiple borides, are those which
most readily take up nitrogen, and have been previously mentioned. Amongst
them, magnesium, barium, manganese, titanated iron are those to be preferred.
By this process the metallic residues composing the ashes are not lost and are
constantly reused, without the necessity of habitually adding new elements other
than the carbon which has been burnt, and which has to be replaced. The ashes
lixiviated by heat give the alkaline boracic solution useful for the impregnation of
the fresh carbon, and the dried insoluble residues serve to cover or coat this carbon, "
after draining the same. The ammoniacal salts obtained, and the ammonia are
very pure, free from arsenic, sulpho cyanides, and sundry other impurities, providing
operations are carried out in the manner hereinafter set forth in the description,
and the improved apparatus which forms a part of the present Invention
employed.
The producing apparatus is formed either of cast iron or of impermeabilized fire-
clay retorts (18), Figure 2, placed vertically in a special furnace. . A fixed part fat the
lower part of the retort is provided with a grate g for the passage of the ashes, and
with an enclosed end with door ch, h, k, t, set in the masonry of the furnace; this.
part is more advantageously made of cast iron. The body of the retort e is of cast
iron or fire clay, and is placed vertically on the lower part f, so as to make a
tight joint at e, f, by means of asbestos packing arranged in a groove formed in
the part f, see Figure 7. The joint is made by the weight of the body e of the
retort. In the same way another part & which forms a cover is placed on the top
of the aforesaid body e, and makes a tight joint therewith at d', e'. The upper
closed end ch, i, j, t, is arranged similarly to the lower one, and the upper part d is.
advantageously made of cast iron.
At the lower part of the tube which conducts air or nitrogen and steam into the
incandescent substance penetrates to the centre of the retort. This tube, a straight.
portion of which is set in the masonry, is directed into the retort by a bend o¹, and
above a given line e¹, f¹, it is pierced with oblique openings from above downwards
by which the inlet gases are forced to disseminate in the mass of the substance, and
to produce the maximum effect. On the outside this tube communicates with a
metallic mixing box o into which the air or the nitrogen coming from the supply
tube Az enters by a cock r¹. The steam coming from the supply tube s enters the
mixing box o through a suitable cock r.
At the upper part of the retort the cover d is lengthened into a chimney i, from
which passes an oblique pipe extending from below upwards for the outlet of the
gases produced, which are conducted through a valve m to a collecting pipe n which
is in connection with the general collector u (dotted in Figure 1), passing thence to
a tube which is in connection with the rest of the apparatus.
The method of closing the upper and lower ends of the retort is shown at Figure 9,.
and is as follows:-
A metallic plate held in position by a hinge ch has a projection to take into a
groove in the upper or lower part i or of the body of the retort, and the contact
of the same is effected by the pressure of a screw t on an angle iron. There are
three of these screws at each door, and the hinge forms the fourth side. At the
bottom of each groove a hermetically tight joint is made with a band of asbestos by
the pressure thereon due to the annular projection on the plate ; or k.
Any desired number of this kind of retort, the dimensions of which may be varied
according to circumstances, are placed in a special furnace, the arrangements of
which are shown in Figures 1, 2, 3, 4, 5, and 6, the indicated direction taken by the
air and hot gases on the line c, c, d, making them easily understood. The air entering
by the ash pits 1, Figure 3, passes through the fuel in the furnaces 2, where it
becomes changed to a mixture of carbonic acid, oxide of carbon, and nitrogen. The
hot gases of combustion ascend through inclined flue 3 against the fire bridge 4, and
pass into a space in which a retort is mounted. They are in some measure drawn
through small openings in the upper part of such spaces, but the greater portion.

page_text: 4
is drawn through openings d at the lower part thereof. They then pass into other
spaces 6 in which other retorts are fixed, which spaces they fill; they then pass
through the openings at the upper part of such spaces into flues 7 which conduct
them to the large draught chimney. This arrangement causes the action of the
heat to be regulated, but this regularity is still further insured by the heating
chambers 8 (Figures 1 and 6), their purpose being to store up the caloric in the
greatest possible proportion. To this end the brick walls of these chambers are
pierced with openings o, v, arranged in zigzag direction, that is to say, not opposite
to each other; the hot air of the spaces 6 occupied by the retorts passes into them,
bringing these walls to a red heat, and this temperature is kept constant by reason
of the continuity of the current and the low conductibility of the material.
The other parts of the apparatus are arranged so as to be in connection with the
furnaces containing the retorts. The resulting gases which pass out of the retort
through the outlet tube l, valve m, and collector n pass into another collector u,
thence into a tube v and through another valve m into a closed vessel 19 which
contains milk of lime for retaining the carbonic acid, the sulphuretted hydrogen,
the empyreumatic, and tarry products.
The vessel has no particular features of novelty, and the arrangements which it
presents are well known in chemical industries. Thence the gas already purified
passes into a close washer 20, where it is washed by means of water only, then
through another valve m into another washer 21, also close, and containing water
and a little lime. When the spaces to be passed through are somewhat long it may
be advantageous to place a suction and force pump in front of the last mentioned
washer 21. On the other hand, if the mixtures adopted for the work of the retorts
contain substances that may be partially carried away by the current it is prudent
to arrange the water washer 20 in the place of the lime vessel 19, and vice versa, in
order that these substances may be prevented from passing away at the first.
On leaving the lime washer 21 the ammoniacal gas, mixed only with a little
water, passes into a condenser 22, and the liquid product is delivered into a receiver
23 through a cock r, rl, and pipe 8, 8, the cock 1, r, leading to close water vessels
14, 15 remaining closed. The gaseous non condensed portion is dissolved, according
to the ordinary method of manufacture, in water placed in a number of receivers 24,
24, 24, provided with safety funnel tubes. In connection with the last of these
receivers 24 a dip tube 8, 8¹¹11, carries the undissolved gas into an acid solution or
into a decomposable saline solution. From time to time the liquid ammonia is
drawn off from the receiver 23, and in the same manner the liquid is collected from
the receivers 24 when it is sufficiently concentrated.
When, instead of preparing liquid ammonia, it is desired to produce ammoniacal
salts, and particularly sulphate, the operation is performed in a different way,
namely: In connection with the condenser 22 the cock r, ', leading to the receivers
is closed, the cock r, r, is opened, and the liquid or gaseous products pass through a
tube o, o, and cock p, p, bubbling through the water contained in the close vessel
14. According to the requirements of the case, a saline solution to be concentrated,
or water, is placed in an evaporating vessel 10 and in a refrigerator 11. A pump
12 is put in motion when the furnace is beated to a red heat. Immediately that
the gaseous current (the product of combustion), composed of carbonic acid, carbonic
oxide, and nitrogen, is drawn from the flue 7 leading to the draught chimney
through a tube 9, it passes through another tube x into the tubes w of the evapo-
rating vessel 10 to the liquid, of which it gives up a portion of its heat, then through
a tube
into the refrigerator 11, from which it is taken by the pump 12 and con-
veyed by bubbling into a water washer receiver 13, from which a tube a, a, conveys
it into the vessel 14 through a cock b, b, by means of a dip tube. On the contact
of the ammoniacal liquid and ammoniacal gas carried through a cock p, p, coming
from the condenser 22 through a pipe o, o, this gaseous current gives up its carbonic
acid to the ammonia, which passes into the carbonated state. The nitrogen, carbonic
oxide, and a small proportion of ammonical. product, carried along or escaping the

page_text: reaction, passes out through a pipe d, d, and is conducted by a pipe m, m, into a
close vessel 16 which contains an acid solution or a decomposable saline solution for
retaining the ammonia. The nitrogen gas, purified from the carbonic acid and
retaining only carbonic oxide, passes through a pipe n, n, into the washer receiver
17 provided with a safety valve. From that vessel a cock directs it into a tube a, z,
towards the distributing tube p which furnishes it to the mixing boxes o for the
formation of azotures (nitrides) in the retorts.
When the ammoniacal solution of the vessel 14 is well carbonated the work is
transferred to another similar vessel 15 simply by the turning of cocks. The liquid
of vessel 14, drawn off through a cock f, f, passes by a tube h, h, into a vat 25 which
contains roughly pulverized gypsum. On contact with the gypsum or sulphate of
lime the carbonate of ammonia changes to sulphate, and carbonate of lime is formed.
The reaction is completed in other vats 25¹ and 25 where the liquid passes through
syphoidal tubes j, j. The sulphate solution is collected at the outlet 1, 1, of the vat.
25, and is conveyed to the refrigerator 11 and to the evaporating vessel 10 for
concentration. Crystallization is effected in the ordinary manner, and the other
salts are prepared by known means.
To avoid useless stoppages and loss of time parts 10, 11, 12, 13, 14, 19, and 20 of
the apparatus are in duplicate, so that the two sets 10, 11, 12, 13 may be worked at
the same time, and the vessels 14, 15, 19, and 20 alternatively.
By the combination of these arrangements considerable advantages are obtained
in the matter of economy.
The waste heat is utilized for the concentration of the saline liquids in the
evaporator 10. The purification of the nitrogen in the various vessels 14, 15,
and 16, allows of the transformation free from cost of the ammoniacal product into
carbonate, which is the condition of the decomposition of gypsum, and avoids the
expenditure in sulphuric acid for the formation of sulphate, which by this fact
itself is free from arsenic, although in some cases where gypsum is difficult to
obtain or expensive sulphuric acid may be used, in which case the apparatus would
be suitably modified as will be readily understood. And the operation is rendered
more profitable by the employment of nitrogen instead of air, the current being less
destructive to the carbon in the retorts.
The method of working for liquid ammonia is very simple. Preparation of
alkaline boracic carbon dried and coated by the aid of one of the oxides, carbonates,
or borates mentioned; the introduction of this carbon into the retorts up to a
little below the outlet tube l; hermetically closing of the covers j and k; elevation
of the temperature up to a red heat; water having been caused to arrive at the
line of level in the vessels 10, 101, 11, 111, 13, 13¹; milk of lime in 19, 191, 14, 15,
and 21; water in 20, 21, and 22; acidulated water, or a decomposable saline
solution in 16 and 24; and water having been introduced up to the proper level
in the vessels 24, 24', and 24", the valves m are opened to the outlet of the retorts
before the vessels 19, 20, and 21, the set 191, 20', remaining closed. The cock r, r¹,
is opened, but the cock r, r, is closed. The cocks b, b, and b, b', on 14 are also
opened. When the fire is well alight so that the retorts begin to get red the pumps
12 and 12 are set to work. The hot gases pass into 10, 10, 11, 11, 12, 12',
13, 13', then into vessel 14, where they lose their carbonic acid on contact with the
milk of lime, and they pass through the vessel 16 and pipe n, n, into the reservoir
17. When the retorts are quite red the substance in the retorts is acted on either
by causing to pass successively a current of nitrogen, coming from the reservoir 17
through pipes a, z, u, p, r, and mixing box o, then a current of steam through 8, r,
and mixing box o, or by the simultaneous introduction of nitrogen and steam. The
ammoniacal product is purified in 19, 20, 21, condensed in 22, and then passed
into the receiver 23. The residue is dissolved in the receivers 24, 241, and 24¹¹.
When the lime of vessels 19 aud 14 is exhausted the current of the products is
made to pass through vessels 19' and 20', and that of the burnt air through vessel
15, whilst the renewal of the lime for purification is being effected in 19 and 14.

page_text: About once a day the working of each retort is stopped in succession for some
minutes for the purpose of opening the lower door k and causing the ashes to fall
down which are collected; the door is again shut, and the upper one j opened to
replace with prepared carbon that which has been consumed, after which the upper
door j is again closed and the working continues. To stop a retort an air cock on
the outlet tube between 1 and m (not shown in the Drawings) is opened, and the
cocks and 1 and the valve m are closed. On the renewal of work the air cock is
closed, and the cocks and the valve which had been closed are again opened.
For the production of sulphate of ammonia the method of operation is identical
with that above described, only the vessels 25, 25, and 25" are charged with
gypsum; other vessels 10, 10', 11, and 11', receive the saline solution to be evapo-
rated instead of water; 14 and 15 receive water instead of milk of lime; the cock
r, r, is closed; r, r, is opened; and the ammoniacal product is directed through.
o, o, and p, p, into the close vessel 14, instead of being conducted towards the
receivers 23 and 24 through the cock r, r¹. The remainder of the work has been
previously described.
The vessels of the apparatus other than the retorts are of sheet iron except the
transition vessel 16 which is of lead and in duplicate.
The tubes are of iron, as are the valves and cocks; the receiving vessels 23, 24,
241, 241, and 24111, may be made of lead, and all the tubes dipping into sulphuric
liquid are also of lead.
In some cases, for security of working, a condenser and receiver may be inter-
posed between the retort and the valves m, or the gases may be pumped from the
retort to the vessels.
Having thus described the nature of the said Invention, and the mode in which
the same is carried into effect, I would have it understood that I do not claim the
manufacture of ammonia by passing currents of ordinary air, nitrogen, or burnt air
and steam through retorts charged with incandescent carbon, nor the methods
hitherto in use of forming the salts of ammonia, nor do I claim the employment of
the apparatus herein described separately considered; but what I do claim is,-
First. The production of amorphous boron, or of a simple boride, or of multiple
borides, for the purpose described, by the reduction of boracic acid, borates, and
metallic oxides by the aid of a nascent alkaline metal in presence of carbon at a red
heat, substantially as herein described.
Second. The transformation of amorphous boron or of the borides mentioned into
nitrides by a current of air, burnt air, or nitrogen at a red heat under the con-
ditions mentioned, substantially as and for the purpose herein described.
Third. The elimination of nitrogen in the state of ammonia by means of nascent
hydrogen produced by steam and reacting on the nitrides formed, substantially as
herein described.
Fourth. The successive or simultaneous employment of air, burnt air, or nitrogen,
with steam on the nitride of boron, or the double or multiple nitrides of boron, and
of one or more of the metals mentioned, either after their formation or as they are
formed, which process allows the intermittent or continuous production of ammonia
as may be desired, substantially as herein described.
Fifth. The preparation of alkaline-boracic carbon or coke covered over with a
layer of oxide, carbonate, or borate of one or more of the metals mentioned for the
purpose of drying, substantially as and for the purpose herein described.
Sixth. The particular construction of the retorts employed, enabling the body of
the retort to be taken away and replaced without destroying the furnace; the
arrangement of the groove joints; the system of hinged covers to these retorts;
the curved pipe for the introduction of nitrogen and steam through oblique
openings from above downwards; the method of conducting and introducing air,
nitrogen, and steam, by means of the mixing box, substantially as herein shown
and described.
Seventh. The general arrangement and combination of the plant for the purifi-

page_text: cation, condensation, and production of ammonia in the state of a commercial liquor,
very pure, and free from foreign products such as arsenic, sulpho-cyanides, and
other impurities, substantially as herein shown and described.
Eighth. The general arrangement and combination of the plant for purifying the
current of air of combustion, and in particular the arrangements of the evaporating
vessels 10 and 10', of the carbonating vessels 14 and 15, and of the transition
vessel 16, substantially as herein shown and described.
Ninth. The mode of utilisation of the heat of the current of burnt air, to effect
without cost the concentration of the liquids, and the employment of the carbonic
acid of this current for carbonating the ammonia, thus ensuring the double decom-
positions which serve for the preparation of salts by known methods, and also the
use as a chief reducer of the oxide of carbon mixed with the current of nitrogen,
substantially as herein described.
Tenth. The particular method adopted in the employment of gypsum as a source
of sulphuric acid, substantially as herein described.
Eleventh. The peculiar arrangement of the furnace shewn in Figures 1, 2, 3, 4, 5,
substantially as herein shown and described and for the purposes stated; and
Twelfth. The arrangements of the heating chambers (Figures 1 and 6) to accu-
mulate and store up the caloric around the retorts and to regulate their action,
substantially as herein shown and described.
In witness whereof, I, the said George Neilson Tucker, have hereunto set my
hand and seal, this Twenty second day of April, in the year of our Lord
One thousand eight hundred and eighty.
G. NEILSON TUCKER. (L.S.)