IMPROVEMENTS IN THE PROCESS FOR DECOMPOSING AMMONIAKAL DISTILLATES
Year: 1875

page_text: LETTERS PATENT to Frank Wirth, of the Firm of Wirth &
Company, Patent Agency, of Frankfort-/-Main, in the Empire
of Germany, for the Invention of "IMPROVEMENTS IN THE PROCESS
FOR DECOMPOSING AMMONIAKAL DISTILLATES."-A communication from
Gustav Theodor Gerlach, Doctor of Philosophy, residing at Kalk,
near Deutz (Germany).
Sealed the 21st September 1875, and dated the 14th June 1875.
PROVISIONAL SPECIFICATION left by the said Frank Wirth at the
Office of the Commissioners of Patents, with his Petition, on the
14th June 1875.
I, FRANK WIRTH, of the Firm of Wirth & Company, Patent Agency,
5 of Frankfort-/-Main, in the Empire of Germany, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN THE PROCESS FOR
DECOMPOSING AMMONIAKAL DISTILLATES," to be as follows:-

page_text: in order to produce sal ammoniac, sulphate of ammonia, or nitrate of
ammonia, or soda. Whilst in the ammonia soda process the sole end to
be attained is the manufacture of soda. The object which I desire to
attain by means of my improvements is the most economical utilization
of the gas water.
Where ordinary rock salt is to be used for the decomposition I dissolve
the salt in a concentrated solution of carbonate of ammonia, so that
equivalent amounts are contained in both. Into this solution I convey
carbonic acid gas until bicarbonate of soda is precipitated. The latter
is then separated and heated, and the gas evolved may be again used for
the decomposition of fresh quantities of lyc or solution. The remaining
liquid containing carbonate of ammonia, sal ammonica, and chloride of
sodium, is heated and carbonate of ammonia is obtained, and the lye or
solution is then treated with lime (for the preparation of caustic
ammonia) or it is evaporated to crystallization (by which process sal
ammoniac is obtained). The salt mother liquor or lye returns for the
same circle of operations.
Where Glauber salt (or various sulphates) is to be used I dissolve
crystallized Glauber salt in a concentrated solution of carbonate of
ammonia in such proportion that equal equivalents are contained in the
liquid, which is then treated in the way already described; or by using
Chili saltpetre nitrate of ammonia and soda are obtained as the resulting
products. The carbonic acid gas is in each case obtained from the gases
produced by combustion, such gases, when cooled, being pumped
through saturated soda solutions of the specific weight 1·15, and the
solution being afterwards heated.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Frank Wirth in the Great Seal Patent Office
on the 8th December 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANK 3
WIRTH, of the Firm of Wirth and Company, Patent Agency, of
Frankfort-on-the-Main, in the Empire of Germany, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourteenth day of June, in the year
of our Lord One thousand eight hundred and seventy-five, in the thirty- 3

page_text: eighth year of Her reign, did for Herself, Her heirs and successors,
give and grant unto me, the said Frank Wirth, Her special licence
that I, the said Frank Wirth, my executors, administrators, and
assigns, or such others as I, the said Frank Wirth, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE PROCESS FOR DECOMPOSING AMMONIAKAL DISTILLATES," a communication
from Gustav Theodor Gerlach, Doctor of Philosophy, a person resident
at Kalk, near Deutz (Germany), upon the condition (amongst others)
that I, the said Frank Wirth, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Frank Wirth, do hereby declare
the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement :—
The following description refers to a process for decomposing ammo-
niacal distillates, such as are obtained in the distillation of gas water
from gasworks, in bone black factories, from coke ovens, and other
industrial establishments. The decomposition is accomplished by
common salt, Glauber salt, or Chili saltpetre, sal ammoniac, sulphate of
ammonia, or nitrate of ammonia being obtained, and on the other hand
carbonate of soda or bicarbonate of soda is produced.
The ammoniacal distillates, as obtained by the distillation of gas
water from gasworks, as well as from bone-black establishments and
coke ovens, have hitherto been generally treated in the following
manner:-
In order to obtain caustic ammonia the gas water is distilled with
lime, and in order to get carbonate of ammonia the ammoniacal vapours
are brought together with carbonic acid.

page_text: In order to produce sulphate of ammonia the ammoniacal distillates
are conveyed into sulphuric acid or they are brought together with
gypsum, whereby sulphate of ammonia is obtained.
For producing sal ammoniae the ammoniacal distillates are conveyed
in hydrochloric acid, or into solutions of carthy or metallic chlorids
(for instance, chloride of calcium or manganese lyes).
Chloride of sodium finds application in the so-called ammonia soda
process, and I shall immediately take occasion to call attention to a
very essential difference between my process and the so-called ammonia
soda process.
In the ammonia soda process the sole end is the manufacture of soda,
while the end I wish to attain is the most cconomical utilisation of the
gas water. Apart from the soda I obtain sal ammoniac, or the solution
of this latter may be used for the preparation of ammoniacal liquor or
carbonate of ammonia.
On the decomposition of ammoniacal distillates by means of rock
salt, sea salt, or saline lyes, I prepare a concentrated solution of
carbonate of ammonia by the distillation of gas water, and dissolvo
common salt or chloride of sodium in it, and in such a quantity that
equivalent amount of chloride of sodium and carbonate of ammonia
are contained in the concentrated solution. In this solution I convey
carbonic acid gas until bicarbonate of soda ceases to precipitate, hereby
hydrosulphuric acid pass off. By distilling gas water with lime result
a ammoniac liquor without hydrosulphuric acid, but by use of this
distillate it is necessary to convey afterwards two equivalents of acid
carbonic for precipitation, bicarbonate of soda. The bicarbonate of
soda is separated from the liquid by means of a centrifugal machinc or
sucking apparatus.
In order to regain the one equivalent of carbonic acid the bicarbonate
is heated, and the gas evolved is again used for the decomposition of
new quantities of lyes, or it is boiled in closed vessels with so much
water that a concentrated soda lye results which is crystallised, while
on the other hand the carbonic acid is regained, or the bicarbonate of
soda is the final by-product.
The liquid obtained from the sucking apparatus, chloride of sodium,
and sal ammoniac as well as carbonate of ammonia.

page_text: For regaining the carbonate of ammonia the liquor is heated, and
the lye, which then only contains chloride of sodium and sal ammoniac'
is either treated with lime (for the preparation of caustic ammonia or
carbonate of ammonia), or it is evaporated to crystallisation, by which
process sal ammoniac is produced.
The salt or mother lyc, which still contains some sal ammoniac, is
used in the course of further operations by being again saturated with
new products of distillation.
In the so-called ammonia soda process a concentrated salt solution is
saturated to a certain degree with caustic ammonia, whereupon carbonic
acid is conveyed into this solution until no more bicarbonate of soda
precipitates. The sal ammoniac formed thereby is decomposed with
caustic lime, and hence the ammonia returns in the operation as caustic
ammonia. However, it is a fact that at most two-thirds of the salt are
decomposed, one-third of this latter being lost as chloride of calcium,
the time being also lost; but the most important loss is that caused by
the volatilization of the ammonia. My process differs from the soda
process in the following
First. The gas water is utilized in the best possible way, new
quantities being continually brought into circulation.
Second. The sal ammoniac produced is not decomposed by time, and
thus is not introduced again in the operation, but is separated by
crystallisation; furthermore, no loss of ammonia is incurred.
Third. There is no lime necessary except the small quantity required
in the distillation of the gas water for decomposing the combined
ammonia salts.
Fourth. The one-third of the salt mentioned above is not lost, but
returns again into the circulation. Hence I gain for every equivalent
chloride of sodium, also an equivalent of bicarbonate of soda, while in
the ammonia soda process these equivalents of chloride of sodium
produce at most two equivalents, bicarbonate of soda.
Fifth. The carbonic acid contained in the gas water as carbonate of
ammonia is also being used, while in the ammonia soda process caustic
ammonia or sal ammoniac decomposed by limo is made use of.
Sixth. Apart from the gas water which is distilled off no waste
produce need be separated.

page_text: At the completion of the operation I separate the bicarbonate of soda
from the lye and change it into soda. The lye is heated to drive out the
dissolved carbonate of ammonia, and the sulphate of soda is separated
from the sulphate of ammonia by crystallization. The Glauber salt is
used again in the operation of being brought together with new
quantities of Glauber salt and carbonate of ammonia produced from new
quantities of gas water.
On the decomposition of the ammoniacal products of distillation by
means of Chili saltpetre I prepare a solution containing for one
equivalent nitrate of soda an equivalent carbonate of ammonia. The
process is exactly the same as in the decomposition of salt and Glauber
salt, the final products that are obtained being nitrate of ammonia and
soda. In the same way, although this is a less profitable operation, the
ammoniacal products of distillation may be decomposed by chloride of
potassium, but hereby a great quantity of bicarbonate of ammonia
constantly precipitates with bicarbonate of potassa, sal ammoniac and
potash are obtained as final products.
As acid carbonic gas in all these cases can be used the cooled gases
from a coke fire or from a limekiln, or the acid carbonic can be prepared
in a more pure state by pumping cooled fire gases from coal or coke or
from a limekiln through a saturated soda solution. Hereby the acid
carbonic is absorbed, and bicarbonate of soda, for the use of pure acid
carbonic, is precipitated. While the atmospheric air and the nitrogen
contained in the fire gases pass off a pure acid, carbonic, can also be
produced by heating marble or lime in closed vessels or by decomposing
carbonates with acids. This process for decomposing ammoniacal dis-
tillate by alkalies may be carried out with the most varied apparatus.
The distillating apparatus for the gas water, as well as the apparatus for
the saturation of the lyes with carbonic acid, the centrifugal machine,
and the drying contrivances for the various salts may be constructed in
different ways, hence I do not claim any special apparatus.
At present the products of the distillation of ammoniacal liquors are
conducted into acids; however, under my Patent I employ alkaline or
their solutions. Until now only common salt was used in the decom-
position of said liquors, but simply and exclusively for the purpose of
producing soda. The lyc containing the ammonia was continually
decomposed by lime, therefore the production of soda by this ammoniac

page_text: soda process would immediately be terminated if the lye containing
the ammonia would be evaporated for the purpose of obtaining sal
ammoniac.
Never and at no time ammoniacal liquors were decomposed with
alkaline in such a manner that at the same time all the ammonia
contained therein was gained as sal ammoniac, and the same time soda
as a valuable by-product much less was at a any time a practicable
attempt made to manufacture sulphate of ammonia or nitrate of
ammonia in the manner proposed by me. This method, however, as
appears at the first glance, offers an enormous advantage over the
present mode of working with acids. For against a small additional
outlay of working expenses and apparatus the costs of the acids are
very much diminished by the application of the cheap alkali salts,
whereby the sodium of the soda is introduced really gratis. A very
considerable advantage of my process is that the sulphate of ammonia
being crystallized is quite white.
Having thus particularly described the said Invention as communi-
cated to me, and the manner of performing the same, I have to state
that I do not restrict myself to the precise details herein described or
delineated, but that what I believe to be novel and original, and claim
is, the new and useful manner for working the gas water and the
decomposition of the ammoniacal liquors by alkalies for obtaining at
the same time ammoniac or ammoniacal salts and soda or bicarbonate
of soda.
In witness whereof I, the said Frank Wirth, have hereunto
set my hand and scal, this Thirtieth day of November, in the
thousan