IMPROVE- MENTS IN THE PROCESS OF MANUFACTURING AMMONIA
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I ALFRED FELDMANN, doctor of philosophy of 1b Dechanatstrasse Bremen,
German Empire do hereby declare the nature of the said invention for "IMPROVE-
MENTS IN THE PROCESS OF MANUFACTURING AMMONIA " to be as follows:-
In manufacturing liquid ammonia according to the customary methods, the
ammoniacal water obtained in the dry distillation of coal, bones, peat and the like,
is subjected to distillation mixed with caustic lime.
The presence of the calcic mud in the still considerably impedes the complete
expulsion of the ammonia and the subsequent removal of the lime residues is an
inconvenient and unpleasant operation..
To obviate these difficulties I eliminate the insoluble lime compounds formed by
the causticising before distillation takes place, and either by a filter press or a
centrifugal apparatus any sulphur compounds that may be present can be previously,
removed by well known methods. After elimination of the lime compounds the
disstillation is effected much more easily, the ammonia is obtained without loss and
the distillation can be carried out in a customary working column still. The same
manner of proceeding may be adopted in manufacturing concentrated ammonia-
water (so called concentrated gas water) The continuously working stills heretoforo
used produce the ammonia water in a strength of only 12 to 15% of ammonia.
If the concentration is pushed further carbonate of ammonia is eliminated and
chokes the cooling devices If however the crude ammonia water is wholly or even
partly deprived of carbonic acid by means of caustic lime and if the insoluble,
lime compounds are eliminated before distillation as hercinabove stated the
concentrated ammonia water of any required degree of concentration can be
directly produced in column stills whereby a distillate of considerable per centage
and consequently a marketable product is obtained In practising the process the
raw ammonia water or gas-water is placed in a vessel and mixed in the well known
proportions with milk of lime or dry calcium-hydrate and intimately mingled by
stirrers.
After the decomposition has been completed the mixture is placed on a filter
press or a centrifugal filter, the solid compounds are separated from the liquid and
the latter is subjected to distillation. In manufacturing concentrated ammonia
water a part- only of the carbonate of ammonia need be decomposed by lime
vizt such portion only that at the highest degree of concentration to be obtained
the distillate will not give up crystals in the cooler.

page_text: The presence of the calcic mud in the still considerably impedes the complete
expulsion of the ammonia and the subsequent removal of the lime residues is an
inconvenient and unpleasant operation.
To obviate these difficulties I eliminate tho_insoluble_limo_compounds formed by
the treatment with caustic lime before distillation takes place, either by a filter.
press or a centrifugal-apparatus; any sulphur-compounds that may be present can
be previously removed by well known methods. After elimination of the lime
-compounds-the distillation is effected much more easily, the ammonia is obtained
without loss and the distillation can be carried out in a continuously working
column-still. The same manner of proceeding may be adopted in manufacturing
concentrated ammonia-water (so-called concentrated gas water). The continuously
working stills heretofore used produce the ammonia water in a strength of only
12 to 15% of ammonia.
If the concentration is pushed further, carbonate of ammonia is eliminated and
chokes the cooling devices. If however the crude ammonia water is wholly or even
partly deprived of carbonic acid by means of caustic lime and if the insoluble lime
compounds are eliminated before distillation as hereinabove stated, the concentrated
ammonia water, of any required degree of concentration can be directly produced
in column-stills whereby a distillate of considerable percentage, and consequently
à marketable product is obtained. In practising the process the raw-ammonia
water or gas-water is placed in a vessel and mixed in the well known proportions
with milk of lime or dry calcium-hydrate and intimately mingled by stirrers.
After the decomposition has been completed the mixture is placed on a filter
press or a centrifugal filter, the solid compounds are separated from the liquid and
the latter is subjected to distillation in continuously working column-stills or other
suitable stills. In manufacturing concentrated ammonia water a part only of the
carbonate of ammonia need be decomposed by lime, viz, such portion only that at
the highest degree of concentration to be obtained the distillate will not give up
crystals in the cooler.

page_text: Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
In the manufacture of liquid ammonia or of concentrated ammonia water with
a high percentage of ammonia, the elimination by means of filter presses or
centrifugal apparatus, of the insoluble lime compounds forming under treatment
with caustic lime, before distillation.