Improvements in the Method of Vapourizing Solutions Containing Nitrates of Manganese, and in the Means used for Decomposing the said Nitrates.
Year: 1890

page_text: Date of Application, 28th Jan., 1890
Complete Specification Left, 16th Oct.. 1890-Accepted, 6th Dec., 1890
PROVISIONAL SPECIFICATION.
Improvements in the Method of Vapourizing Solutions Containing
Nitrates of Manganese, and in the Means used for Decomposing
the said Nitrates.
I, GEORGE WISCHIN, of 3 Fonarni, St. Petersburgh, Russia, Doctor of Philosophy,
do hereby declare the nature of this invention to be as follows:-
This invention relates to the vapourization of solutions containing nitrate of
manganese and the decomposition of the said nitrate for the purpose of recovering
the nitric acid and the peroxide of manganese contained therein while preventing
these solutions from coming into direct contact with the walls of the vessel forming
part of the apparatus used, and likewise avoiding an incrustation of the peroxide of
manganese on the walls of the vessel, this process being carried out by gra lually
bringing, in suitable apparatus, such solutions in small quantities in contact with
powdered, granulated, or broken substances, preferably peroxide of manganese, or
pyrolusite, which have a very slight, or no chemical action upon these solutions under
continuous stirring and heated at, or somewhat above the temperature of decomposition
of the nitrate of manganese.
The invention consists of bringing solutions of nitrate of manganese, such as are
obtained in the preparation of chlorine, for instance, by the action of peroxide of
manganese and nitric acid upon hydrochloric acid, or chloride of manganese, in
contact with pulverized, granulated, or broken substances, preferably pyrolusite, or
peroxide of manganese, which have a very slight, or no chemical action upon these
solutions and further in heating the same while continuous stirring in suitable
apparatus at, or slightly above the temperature of decomposition of the nitrate of
manganese, whereby the said solutions are vapourized without coming in direct
contact with the walls of the vessel in the apparatus and at the same time, to
gather in a free state, the peroxide of manganese formed by the decomposition of
the nitrate of manganese without any incrustation being formed.
I shall now proceed to describe in what manner and by means of what apparatus
the residual mother liquor from the chlorine process can be suitably treated for
recovering therefrom the peroxide of manganese and the nitric acid, although I must
clearly state that the manner of carrying out the process, as well as the construction
of the apparatus and the material of which the latter may be manufactured can be
modified in various ways, the main feature of the invention being the gradual inter-
mixing of the liquor with heated substances hereinafter more particularly referred
to. I may remark at the same time, that I use preferably inother liquors or lyes
formed by the action of peroxide of manganese and nitric acid upon dry chloride of
manganese. By condensing the steam forined containing nitric acid, a relatively small
volume of diluted nitric acid is obtained which can be used for the absorption of the
nitric acid recovered.
I heat a cylindrical, vertical, and enclosed cast iron vessel provided at the top with
an outlet pipe for the steam, and having a diameter of about 3 metres and a height of
about 1 metre, in which vessel, is arranged a stirring device, or agitator operating
particularly upon the bottom thereof, and set in motion after having previously
introduced in the said vessel through an opening in the cover, capable of being closed,
a pre-determined quantity of pulverized peroxide of manganese, or after having
prepared therein, a similar quantity of the same substance at a necessary temperature.
Care must be taken that the parts of the vessel's walls which are not covered by
peroxide of manganese should be at least heated to such an extent that no nitric acid
vapours may precipitate upon these walls. I admit now the liquor through numerous
perforations formed in the cover by means of small tubes, so as to fall in fine jets upon

page_text: the peroxide of manganese contained in the vessel, or the liquor may be farther
divided or broken up by means of a turbine, such as used for acids, the heated
peroxide of manganese being continuously stirred by means of the agitator. The
vapours and gases disengaged are allowed to escape, the nitric acid being afterwards
extracted therefrom by any well known processes.
The peroxide of manganese formed by the decomposition of the nitrate of manganese
becomes mixed with that originally introduced, or present in the vessel, and can be
periodically, or continuously removed therefrom through a suitable opening.
Dated this 28th day of January 1890
H. GARDNER,
166, Fleet Street, London, Agent for the said George Wischin.
COMPLETE SPECIFICATION.
Improvements in the Method of Vapourizing Solutions Containing
Nitrates of Manganese, and in the Means used for Decomposing
the said Nitrates.
I, GEORGE WISCHIN, of 3 Fonarni, St. Petersburgh, Russia, Doctor of Philosophy,
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 ---
It is known that, in order to produce chlorine by the action of equivalent quantities
of nitric acid, peroxide of manganese and hydrochloric acid, or of 2 equivalents of
nitric acid one equivalent of peroxide of manganese and one equivalent of chloride
of manganese, a mixture of those ingredients, is subjected to a temperature of
about 212° F. in suitable vessels, whereby chlorine is evolved, whilst in the vessel
remains a solution, containing principally nitrate of manganese, with comparatively
small quantities of nitric acid, or hydrochloric acid, which solution is more or less
diluted by water, according to, whether hydrochloric acid or dry chloride of manganese
has been used. If the said solution or solutions of nitrate of manganese, which I
henceforth call liquors, be first evaporated in iron pans, opened at the top, to the
point of the beginning decomposition of nitrate of manganese and the residue,
transferred to suitable iron apparatus, in which the decomposition by heat of the
nitrate of manganese in peroxide of manganese and nitrous acid, is effected, it only
remains, to remove the peroxide of manganese, produced in the decomposing
apparatus and to convert, by well known means, the escaping nitrous acid into
nitric acid and both of them may now be used and reconverted an indefinite number
of times.
The evaporations of the liquors and the decomposition of the nitrate of manganese
which they contain, presents principally two difficulties.
1. Iron vessels are strongly acted upon by the acid liquors.
2. Hard crusts of peroxide of manganese (firmly attaching themselves to the
bottom of the decomposing vessel) are produced, which are difficult to remove and
prevent the transmission of heat to the nitrate of manganese to be decomposed.
The object of the present invention is to overcome these difficulties and I now
describe how I proceed and illustrate in the annexed drawing what sort of apparatus
I purpose using to attain this object, although I do not confine myself strictly to the
use and the construction of the apparatus shown, nor to the exact mode of working,
as hereafter described.
Essential is the gradual supply and in small quantities of the liquors into an iron
vessel, the bottom of which is covered with powdered or granulated substances to
prevent the liquors acting injuriously upon the vessel. It is preferable to employ
powdered or granulated peroxide of manganese, and it is important that no part of
the vessel is so cold that liquid nitric or muriatic acid will be condensed, it is also
important that the said liquors do not come in direct contact with the sides of the iron
vessel, but only with the powdered or granulated substances, which substances should
be heated to about 400° F. or generally speaking to the proper temperature of

page_text: decomposition of nitrate of manganese, and should be stirred or overturned by an
agitator moving inside the iron vessel, whereby the evaporation of the liquors and the
decomposition of the nitrate of manganese takes place from the heated surface of the
said substances and whereby also the formation of the crusts is avoided, and so
the two objects, namely avoiding the injurious action of the liquors upon iron vessels
and formation of hard crusts of peroxide of manganese are attained.
I must also mention that I am using with praference liquors which have been
obtained by using chloride of manganese instead of muriatic or hydrochloric acid, by
reason of being so enabled to use the liquors directly, without previous evaporation in
open vessels and neutralization of the free acid they may contain, both of which must
be done with liquors obtained by hydrochloric acid, as it is required to first of all get
rid of all the water introduced into the liquors by the use of muriatic acid by
evaporation (in order to obtain the recovered nitric acid of proper strength) the
evaporation in iron pans, necessitating the previous neutralization of the acid liquors.
The further treatment is the same, whether liquors produced with chloride of
manganese or hydrochloric acid are used.
A represents a cylindrical cast iron pan of about 7 feet diameter and 3 feet high,
with flat bottom and top closed but with apertures (and connections with the recovery
plant of nitric acid) in order to carry away the vapours of water and nitrous acid,
further with an aperture c for removing periodically or continuously the peroxide of
manganese produced and finally with the branch pipes i, i, for introducing the liquors.
The pan is placed in a furnace, preferably over a perforated arch, in order to attain a
proper division of heat.
The stirring of the layer of peroxide of manganese covering the bottom takes place
by means of an agitator, the wings are close to the bottom of the pan to spread it
evenly. The luting of the hole in the pan through which the shaft passes is inade by
a bell g attached firmly and airtight to the agitator shaft and moving in a sand luto.
The equal distribution of the liquors over the heated peroxide of manganese is effected
best by a liquor-distributor o and branches i, i, identical with the acid distributors
used in vitriol works. The introduction of the liquor into the inside of the pan takes
place by means of a number of branch pipes i, i, fixed on the top of the vessel.
Having now particularly described and ascertained the nature of this invention
and in what inanner the same is to be performed I declare that what I
claim is :-
1. The herein before described method of treating nitrates of manganese solutions
for the recovery of nitric acid therefrom.
2. The employment of powdered peroxide of manganese or its equivalent in an
iron vessel as an ingredient to prevent injurious action of nitrate of manganese
solutions thereon during the process of recovering the nitric acid from the solutions,
as set forth.
H. GARDNER,
Patent Agent, 166, Fleet Street, London, Agent for the said George Wischin.