Process and Apparatus for the Manufacture of Concentrated Nitric Acid.
Year: 1892

page_text: Date of Application, 12th Jan., 1892
Complete Specification Left, 6th Oct., 1892-Accepted, 26th Nov., 1892
PROVISIONAL SPECIFICATION.
Process and Apparatus for the Manufacture of Concentrated Nitric
Acid.
I, FRIEDRICH VALENTINER, Doctor of Philosophy, of Plagwitz near Leipzig,
in the Kingdom of Saxony, do hereby declare the nature of this invention to be as
follows:-
This invention relates to the production of highly concentrated nitric acid by the
decomposition of saltpetre by means of sulphuric acid in vacuo, and to apparatus
suitable for this purpose.
I decompose dried saltpetre with sulphuric acid at 66° Beaumé in a vacuum by
means of an apparatus consisting of a retort or still, a cooler, a receiver, a vacuum
chamber, an air pump and certain auxiliary appliances.
From the head of the retort a tube leads to the cooler (in which it forms a coil
surrounded by cooling water) and thence into the receiver, preferably placed
underneath the cooler.
The receiver has preferably the shape of a large flask through the plug of which
passes the tube from the cooler, and which is connected on one side with the
vacuum chamber by means of a tube containing a threeway cock and a pressure
gauge (placed between the said cock and the receiver). Another tube leads from
the vacuum chamber to the air pump.
After the air in the apparatus has been sufficiently exhausted or rarefied by the
air pump, the decomposition of the saltpetre commences, and the acid passes over
into the receiver, which operation may be considerably promoted by heat.
For this purpose we place the retort in or upon a water bath and heat the latter
by any suitable means.
The nitric acid which collects in the receiver in this manner, is drawn off into
flasks or receptacles suitable for transport. It is as clear as water and chemically
pure, free from hyponitric and of nitrous acid, chlorine and water. The specific
gravity at 15 degrees centigrade is about 1.59.
Dated this 12th day of January 1892.
FAIRFAX & WETTER,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Process and Apparatus for the Manufacture of Concentrated Nitric
Acid.
I, FRIEDRICH VALENTINER, Doctor of Philosophy, of Plagwitz near Leipzig,
in the Kingdom of Saxony, 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:-
This invention relates to the production of highly concentrated nitric acid by the
decomposition of saltpetre by means of sulphuric acid in vacuo, and to apparatus
suitable for this purpose.
1 decompose dried saltpetre with sulphuric acid at 66° Baume in a vacuum by
ineans of an apparatus shown in sectional elevation upon the accompanying
drawings; consisting of a retort or still A, (containing the said saltpetre and acid),
a cooler B, a receiver C, a tube D, having a three way cock E, leading from the
receiver C into a vacuum chamber F. Another tube G, also containing a stop
[Price]

page_text: cock is led from the chamber F to a suitable air pump, by means of which the
vacuum is maintained.
From the head of the retort A, a tube leads to the cooler B, in which it forms a
coil surrounded by cooling water, which enters by a lower pipe, (from a suitable
source of supply), and passes off by an upper one in the direction shown by the
arrow. The end of the coil tube passes from the cooler B through the plug of the
receiver C, which is preferably placed beneath the cooler; and the latter is con-
nected to the vacuum chamber F by the tube D, in which is placed a three way
cock E, and, (between the cock E and the receiver C), a pressure gauge H. The
tube G connects the vacuum chamber F to the air pump as already mentioned.
After the air in the apparatus has been sufficiently exhausted or rarefied by the
air pump (indicated on the right hand side of the drawing) the decomposition of
the saltpetre commences, and the acid passes over into the receiver C, which
operation is considerably promoted by heat. For this purpose, the retort A is
placed in or upon a water bath L, which is heated by any suitable means.
The nitric acid which thus collects in the receiver C is drawn therefrom through
the tap J into flasks or receptacles K suitable for transport. It is as clear as
water. The specific gravity at 15 degrees centigrade is about 1.59.
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. The herein described process for the manufacture of concentrated nitric acid
whereby the decomposition of saltpetre is effected by sulphuric acid in a vacuum,
substantially as set forth.
2. In an apparatus for manufacturing concentrated nitric acid, the combination
of the retort A, with a cooler B, a receiver C, vacuum chamber F, and air pump
with communicating tubes G and D, arranged and adapted to operate substantially
in the manner and for the purpose shown and described with reference to the
drawing.
Dated this 6th day of October 1892.
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicant.