An Improved Process of Manufacturing Nitric Acid.
Year: 1899

page_text: Date of Application, 19th Sept.,
1899
Complete Specification Loft 10th June 1900-Accented 11th Aug
1900
Date of Application, 19th Sept., 1899
Complete Specification Left 10th June 1900-Accented 11th Aug 1900
An Improved Process of Manufacturing Nitric Acid.
I, GUSTAV GLOCK, Dr. Philos., of No. 103, Rosenstrasse, Coepenick, near
Berlin, Prussia, in the Empire of Germany, Chemist, do hereby declare the
nature of this invention to be as follows:-
My invention relates to an improved process of manufacturing nitric acid, and
the object of my invention is to prevent the formation of bisulphates in the
course of the process.
The method generally employed of manufacturing nitric acid consists in sub-
jecting to heat saltpetre together with sulphuric acid, within a retort. In pro-
ceeding according to the method generally in use, the necessity exists of employ-
ing more than one equivalent of sulphuric acid, as, otherwise, the charge of
the retort would become solidified, and the solid mass, being a bad conductor of
heat, could not further be heated to that temperature, which is required to.
obtain a complete transformation. By employing a surplus quantity of sul-
phuric acid, the bisulphate of sodium formed during the process will remain in
a fluid state under heat, the transformation is complete and the retort can be
easily emptied. This method of manufacturing nitric acid is advantageous in
those cases, where the bisulphate obtained may be utilized. But most frequently,.
the bisulphate is a waste product of no value at all, and by producing it, the
cost of manufacturing the nitric acid is not only uselessly increased, but still
further encumbered by the expense of removing the waste product.
The improved process of my invention is designed to overcome the incon-
veniences referred to, by preventing entirely the formation of bisulphates.
If one molecule of sulphuric acid is made to act upon two molecules of salt-
petre at a temperature of 100° Centigrade, bisulphate of sodium and nitric acid
will be obtained, while one molecule of the saltpetre will remain unattacked.
The formula is:-
2 NaNo, H,SO, = NaHSO4 + HNO, + NaNO.
After one molecule of nitric acid has been drawn off by distillation, no further
reaction will take place below a temperature of 100° Centigrade.
Only after
elevating the temperature to 120°-130°′ Centigrade, the NaHSO will begin
to melt and exercise its action upon the other molecule of the saltpetre. While
the mass is boiling, one other half molecule of the nitric acid is distilling over,
and subsquently, the mass again becomes solid, yielding no further trace of nitric
acid. If, then, the temperature is further raised-to-2200-Centigrade-or-more,-the-
still remaining saltpetre will entirely enter into decomposition. It is evident
therefrom, that varying acid sulphates are being formed, having different melt-
ing points, and that each of said sulphates only when reaching its melting point
will act upon saltpetre. Now, by subjecting the saltpetre to the action of sul-
phuric acid at the last mentioned temperature, the formation of acid sulphates
is rendered impossible and, consequently, besides nitric acid, only neutral sul-
phate of sodium will be obtained:

page_text: In carrying my invention into practice, I proceed as follows:-
Within a suitable boiler provided with stirring apparatus, saltpetre is heated
to 120°-130° Centigrade. Thereupon the equivalent quantity of sulphuric
acid is gradually added by feeding the same in a fine jet or jets,
while agitation and heating of the mass is continued. The sulphuric
acid, before being introduced, should preferably be heated to 100° to
130° Centigrade. When the determined quantity of sulphuric acid
has been introduced and the development of nitrous fumes has ceased, the
temperature is raised until the saltpetre has been completely decomposed. The
decomposition may be accelerated by introducing water in the form of steam or
fine jets.
Finally, atmospheric air is forced through the apparatus either by
presure or suction, and thereupon the solid, neutral powder of sulphate of sodium
may be exhausted.
Of course, the process may equally well be operated with the modification of
heating the saltpetre from the beginning to about 250° Centigrade.
The process is the same, if nitrate of potassa is treated instead of nitrate of
soda, as before described.
The essential novelty of my invention consists, first, in feeding the sulphuric
acid slowly and by degrees, instead of admixing the total quantity from the begin-
ning, and further, in causing the sulphuric acid to act upon the saltpetre in such
a way, that the latter, from the beginning, is heated to a high temperature, to
prevent the formation of bisulphates, viz. to cause the bisulphates which may
be formed to be immediately transformed into neutral sulphates by their com-
bination with saltpetre.
The advantages derived from the improved process are conspicuous.
First, by feeding the sulphuric acid slowly and by degrees, the attendant has
a full and complete control over the operation of the process, it may be stopped
at any time, without the least disadvantage. With the process generally in use,
it frequently will happen that a strong development of nitrous fumes occurs all
of a sudden; the mass, during the process is subject to violent ebullition, whereby
the conduit pipes and cooling vessels become choked and not only heavy losses
of the mass under treatment, but also eminent dangers to the attendants are
occasioned. All accidents of such kind are entirely excluded by proceeding
according to the improved process before described.
A further advantage consists in a considerable economy of sulphuric acid
emploved, and instead of obtaining bisulphates, neutral sulphates are obtained
as a by-product.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.
COMIDELE DIMITICATION.
An Improved Process of Manufacturing Nitric Acid.
I, GUSTAV GLOCK, Dr. Philos., of No. 103, Rosenstrasse, Coepenick, near
Berlin, Prussia, in the Empire of Germany, Chemist, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be 4
particularly described and ascertained in and by the following statement:—
My invention relates to an improved process of manufacturing nitric acid, and
the object of my invention is to prevent the formation of bisulphates in the
course of the process.
The method generally employed of manufacturing nitric acid consists in sub-

page_text: jecting to heat saltpetre together with sulphuric acid, within a retort. In pro-
ceeding according to the method generally in use, the necessity exists of employ-
ing more than one equivalent of sulphuric acid, as, otherwise, the charge of
the retort would become solidified, and the solid mass, being a bad conductor of
heat, could not further be heated to that temperature, which is required to
obtain a complete transformation. By employing a surplus quantity of sul-
phuric acid, the bisulphate of sodium formed during the process will remain in
a fluid state under heat, the transformation is complete and the retort can be
easily emptied. This method of manufacturing nitric acid is advantageous in
those cases, where the bisulphate obtained may be utilized. But most frequently,
the bisulphate is a waste product of no value at all, and by producing it, the
cost of manufacturing the nitric acid is not only uselessly increased, but still
further encumbered by the expense of removing the waste product.
The improved process of my invention is designed to overcome the incon-
veniences referred to, by preventing entirely the formation of bisulphates.
If one molecule of sulphuric acid is made to act upon two molecules of salt-
petre at a temperature of 100° Centigrade, bisulphate of sodium and nitric acid
will be obtained, while one molecule of the saltpetre will remain unattacked.
The formula is:-
2 NaNo, H₂SO NaHSO + HNO, NaNO.
After one molecule of nitric acid has been drawn off by distillation, no further
reaction will take place below a temperature of 100° Centigrade. Only after
elevating the temperature to 120°-130° Centigrade, the NaHSO, will begin
to melt and exercise its action upon the other molecule of the saltpetre. While
the mass is boiling, one other half molecule of the nitric acid is distilling over,
and subsquently, the mass again becomes solid, yielding no further trace of nitric
acid. If, then, the temperature is further raised to 220° Centigrade or more, the
still remaining saltpetre will entirely enter into decomposition. It is evident
therefrom, that varying acid sulphates are being formed, having different melt-
ing points, and that each of said sulphates only when reaching its melting point
will act upon saltpetre. Now, by subjecting the saltpetre to the action of sul-
phuric acid at the last mentioned temperature, the formation of acid sulphates
is rendered impossible and, consequently, besides nitric acid, only neutral sul-
phate of sodium will be obtained.
In carrying my invention into practice, I proceed as follows:-
-
.
:-
Within a suitable boiler provided with stirring apparatus, saltpetre is heated
to 120°-130° Centigrade. Thereupon the equivalent quantity of sulphuric
acid is gradually added by feeding the same in a fine jet or jets,
while agitation and heating of the mass is continued. The sulphuric
acid. before being introduced, should preferably be heated to 100° to
130° Centigrade. When the determined quantity of sulphuric acid
has been introduced and the development of nitrous fumes has ceased, the
temperature is raised until the saltpetre has been completely decomposed. The
decomposition may be accelerated by introducing water in the form of steam or
fine jets.
Finally, atmospheric air is forced through the apparatus either by
presure or suction, and thereupon the solid, neutral powder of sulphate of sodium
may be exhausted.
Of course the process-may-equally well-be-operated_with_the_modification of
heating the saltpetre from the beginning to about 250° Centigrade.
The process is the same, if nitrate of potassa is treated instead of nitrate of
soda, as before described.
The essential novelty of my invention consists, first, in feeding the sulphuric
acid slowly and by degrees, instead of admixing the total quantity from the begin-
ning, and further, in causing the sulphuric acid to act upon the saltpetre in such
a way, that the latter, from the beginning, is heated to a high temperature. to
prevent the formation of bisulphates namely, to cause the bisulphates which may

page_text: be formed to be immediately transformed into neutral sulphates by their com
bination with saltpetre...
The advantages derived from the improved process are conspicuous.
First, by feeding the sulphuric acid slowly and by degrees, the attendant has
a full and complete control over the operation of the process, it may be stopped
at any time, without the least disadvantage. With the process generally in use,
it frequently will happen that a strong development of nitrous fumes occurs all
of a sudden; the mass, during the process is subject to violent ebullition, whereby
the conduit pipes and cooling vessels become choked and not only heavy losses
of the mass under treatment, but also grave dangers to the attendants are
occasioned. All accidents of such kind are. entirely excluded by proceeding
according to the improved process, before described. ...
A further advantage, consists in a considerable economy of sulphuric acid
employed, and instead of obtaining bisulphates, neutral sulphates are obtained
as a by-product.
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―
•
1:
An improved process for the manufacture of nitric acid whereby the formation
of bisulphates is prevented, which process essentially consists in gradually feed-
ing the sulphuric acid to the saltpetre or other equivalent nitrate, the latter
having been previously heated up to at least 120° Centigrade, substantially as
hereinbefore described.
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