Improvements in the Manufacture of Ammonium Nitrate.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Ammonium Nitrate.
I, THOMAS FAIRLEY, of 17 East Parade, Leeds in the County of York,
Chemist, do hereby declare the nature of this invention to be as follows:-
In the reaction of ammonia and carbon dioxide on saturated solutions of sodium
nitrate or of ammonium bicarbonate, about two-thirds of the sodium nitrate react
with ammonium bicarbonate to give sodium bicarbonate and ammonium nitrate and
about one-third of the sodium nitrate remains unchanged, no matter what excess of
ammonium bicarbonate or of its components may be used. The process therefore
gives sodium bicarbonate which can be readily purified but hitherto ammonium
nitrate has not been obtained free from sodium salts by this means.
The object of this invention is to supply simple means for the manufacture of
practically pure ammonium nitrate from this source.
Using solid ammonium bicarbonate, this salt may be fed into the bottom end of
a suitable extractor apparatus and caused to continuously pass upwards through
the cylinder. At the same time saturated solution of sodium nitrate flows into the
upper part of the apparatus and passes through the column of the ammonium
bicarbonate. The supply can be adjusted so that sodium bicarbonate muistened
with the sodium nitrate solution is delivered at the upper part and the liquid
issuing at the lower end consists of solution of ammonium nitrate with about
30 per cent. of sodium nitrate, along with ammonium and sodium bicarbonates in
smaller quantity.
On exposing this liquid to cold by passing it through a similar apparatus
externally cooled to a temperature which need not be below-15° Centigrade-the
greater part of the ammonium nitrate crystallizes out and most of the other salts
remain in solution. The solid ammonium nitrate is delivered at the upper end of
the apparatus, and can be completely purified by washing with cold water or with
a cold saturated solution of ammonium nitrate. The liquids remaining from the
cooling process can be utilized in dissolving fresh quantities of sodium nitrate.
In the absence of cheaper or more convenient means of obtaining low tempera-
tures for the above operations-the solution of ammonium nitrate in its own
weight of cold water can be used as a cooling agent.
The above process is an application of the fact that below a certain temperature
sodium nitrate is more soluble than ammonium nitrate, and the process can be
applied if desired to mixtures of solid ammonium and sodium nitrates.
Dated this 23rd day of January 1896.
BOULT & WADE,
Agents for the Applicant.

page_text: Improvements in the Manufacture of Ammonium Nitrate.
I, THOMAS FAIRLEY of 17 East Parade, Leeds in the County of Yorkshire
Chemist, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement:--
In the reaction of ammonia and carbon dioxide on saturated solutions of sodium
nitrate or of ammonium bicarbonate on sodium nitrate about two-thirds of the
sodium nitrate is changed into ammonium nitrate and about one-third of the sodium
nitrate remains-no matter what excess of ammonium bicarbonate or of the
components of ammonium bicarbonate may be used. The process therefore gives
sodium bicarbonate which can be readily purified but hitherto ammonium nitrate
has not been obtained free from sodium salts by this means.
The object of this invention is to supply a simple means for the manufacture of
practically pure ammonium nitrate from this source.
If in the ammonia-soda process applied to sodium nitrate solid ammonium
bicarbonate be used-this salt in a powdered or granulated condition may be fed
into the bottom end of an extractor and caused to continuously pass upwards
through the cylinder. At the same time saturated solution of sodium nitrate flows
into the upper part of the apparatus and passes through the column of the
ammonium bicarbonate, the supply can be adjusted so that sodium bicarbonate
moistened with the sodium nitrate solution is delivered at the upper part and the
liquid issuing at the lower end consists of solution of ammonium nitrate with about
30 per cent. of sodium nitrate along with bicarbonates of sodium and ammonium in
small quantity.
Any other of the arrangements used in the ammonia-soda process may be applied
to the conversion of sodium nitrate-so as to give ammonium nitrate and sodium
bicarbonate, for instance the processes described in Wirth's Specification No. 2174
of 1875 and Chance's Specification No. 5919 of 1885.
To facilitate the process for the purification of the ammonium nitrate-the
solutions should be obtained with the minimum quantity of water necessary in the
reaction of sodium nitrate on ammonium bicarbonate or its components. Weak
liquors must be concentrated by evaporation or by the addition of the solid salts
from the complete evaporation of another portion of the liquid.
On exposing such liquids to cold in an apparatus externally cooled to a
temperature of about 15° Centigrade the greater part of the ammonium-nitrate
crystallizes out while the other salts remain in solution. This cooling process may
be carried out in an apparatus similar to that previously referred to, in which case
the liquid is supplied at the bottom and the ammonium-nitrate is delivered at the
upper end and can be purified by washing with cold water or with a cold saturated
solution of ammonium nitrate. The salt may be dried by exposure to a gentle heat
with or without the aid of a hydro extractor.
The liquid remaining from the cooling process is used to dissolve fresh quantities
of sodium nitrate to be used as in the ammonia-soda process.
In the absence of cheaper or more convenient means of obtaining low temperatures
for the cooling process the solution of ammonium nitrate in its own weight of water
can be employed as a cooling agent. It is not necessary for this purpose to use
pure ammonium nitrate as the impure nitrate obtained by the evaporation of the
liquid from the ammonia-soda process applied to sodium nitrate as above described
is preferable to the pure salt. This can be dissolved directly in the liquid and be
cooled without altering the relative proportions of the salts in the liquid, and the

page_text: cooling effect is applied in the most direct manner possible, so that less external:
refrigeration is necessary.
The above process is an application of the fact that below a certain temperature
sodium nitrate is more soluble in water than ammonium nitrate and the process can
be applied to mixtures of solid ammonium and sodium nitrates by dissolving them.
in the minimum quantity of water or, as above mentioned, in the liquor from the
application of the ammonia-soda process to sodium nitrate.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what. I
claim is :-
1. In the manufacture of ammonium nitrate by the ammonia-soda process.
crystallizing out the salt from the mixed liquid by refrigeration and subsequently
washing and purifying the salt substantially as described.
2. The manufacture of pure ammonium nitrate from a mixture of the solid
nitrates of ammonium and sodium by dissolving them in the smallest possible
quantity of water, or in the liquid from the ammonia-soda process, refrigerating the
solutions so obtained and purifying the salt substantially as described.
3. The complete process substantially as described for the manufacture of pure-
ammonium nitrate.
Dated this 23rd day of October 1800
THOMAS FAIRLEY.
Boult & Wade,
Agents for the Applicant..