IMPROVEMENTS IN THE MANUFACTURE OF CAUSTIC SODA AND OTHER ALKALIES AND CORRE- SPONDING SALTS, AND IN THE APPARATUS EMPLOYED THEREIN
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Thomas Morgan at the Office of the
Commissioners of Patents on the 9th December 1879. A communication
from abroad by Theodore Wastchuk, Architect, and Nicholas Glouchoff,
Captain of Artillery, both of Moscow, in the Empire of Russia.
THOMAS MORGAN (Secretary of the Inventors' Patentright Association, Limited),
21, Cockspur Street, Charing Cross, in the County of Middlesex. "IMPROVEMENTS
IN THE MANUFACTURE OF CAUSTIC SODA AND OTHER ALKALIES AND CORRE-
SPONDING SALTS, AND IN THE APPARATUS EMPLOYED THEREIN." A communication
from abroad by Theodore Wastchuk, Architect, and Nicholas Glouchoff, Captain of
Artillery, both of Moscow, in the Empire of Russia.
This Invention consists in an improved process and apparatus for the
manufacture of caustic soda, potash, and like alkalies and salts, by means of
electrolysis, whereby products of greater purity are obtained than has hitherto
been possible in carrying on the manufacture on a large scale, common salt only
being employed, and the whole process completed in one operation.
The principal features of the said Invention consist in expelling the gases which
would otherwise tend to polarize the electrodes, and employing these gases for
supplying batteries for generating currents to be employed as hereinafter described.
Saline solution may, under suitable conditions, bo decomposed by an electric
current, and in case the metal so obtained acts upon water, an acid and oxygen
will be obtained at the positive pole, and a metallic oxide and hydrogen at the
negative pole. If the products of the decomposition are allowed to remain in the
same vessel in which they are formed, the intensity of the current will be weakened
by the polarization of the electrodes, and the substances formed will tend to re-
unite, thereby rendering it difficult to effect a complete decomposition, by this
process, of the salt previously subjected to electrolysis, and a continuous manufacture
of the products has hitherto been impossible.
By means of this Invention these difficulties are overcome and the following
advantages are obtained, viz. :—
(1.) All the products obtained by decomposition are removed as fast as they are
formed from the vessel in which they are generated, and collected in separate
receivers by means of a continuous current of the saline solution, which diminishes
the polarization by washing the electrodes.
(2.) The gases obtained are utilized in different ways depending upon local
economical conditions; (a) by employing the gases generated in one apparatus for
charging the clements of a so-called gaseous galvanic battery for generating a
current capable of producing electrolysis in another apparatus which we denominate
electrolysis of second order; (b) or the hydrogen set at liberty may be employed for
heating purposes, or for driving a dynamo-electric machine, producing a current, or
or evaporating liquids on a large scale, or for any other operation in which heat is
equired.
It will be sufficient to give a general description of the method of preparation
ccording to our improved process; the different details, such as the dimensions of

page_text: the apparatus and their relative arrangement, depend on the building employed and
the scale on which it is proposed to carry on the manufacture.
The local conditions will show which of the substances obtained should be
regarded as principal, and which as secondary products.
In order to give a general idea of the principle of our improved process, we will
now proceed to describe the preparation of soda, according to this Invention, by
the electrolysis of common salt or chloride of sodium (Na Cl). The same process is
also applicable for the manufacture of potash by the electrolysis of chloride of
potassium, but when soda is prepared from sulphate of soda, sulphuric acid will be
obtained as a secondary product instead of hydrochloric acid.
A vessel divided into two parts by a porous partition is employed, each part
containing an electrode.
The electrode on the right forming the positive pole may be of platinum or
carbon, and the electrode on the left or the negative pole is of platinum, carbon,
silver, or iron (by preference iron).
When these electrodes are connected with a generator of electricity, and the
vessel is filled with a saline solution, this solution will be decomposed. On the
right side of the partition chlorine or chloric gas will be generated, which, acting in
part upon the water, will form bydrochloric acid, and this hydrochloric acid, with
the oxygen formed by the decomposition of the water, will pass through a tube
into a vessel half filled with water, where the bydrochloric acid will be absorbed by
the water whilst the oxygen and chlorine are conducted through a suitable pipe to
the gas batteries. On the left side of the partition the action of the current will
reduce the salt to metallic sodium, which, acting in turn upon the water, is
converted into caustic soda, and together with the hydrogen produced by the
decomposition of the water, passes into another vessel, where the caustic soda is
collected whilst the hydrogen gas passes into the gas batteries. Two separate
vessels are provided for the reception of the hydrochloric acid, as well as for the
caustic soda, so that one of each may be employed whilst the other is being cleaned
or repaired without interrupting the manufacture. The saline solution contained
in the divided vessel is introduced into the said vessel by means of a tube com-
municating with the lower part of the vessel and takes the place of the products of
decomposition, at the same time washing the electrodes so as to diminish the
polarization.
The rate at which the saline solution flows into the vessel depends on the energy
of the electrolysis, and the limit of the flow from the vessel containing the caustic
soda may be obtained by testing with nitrate of silver.
We have already stated that the oxygen and hydrogen generated by the
electrolysis are conducted into the gas batteries by ineans of tubes; these tubes
may be divided into two or more branches in order to supply batteries having
several elements, by combining the same in consecutive or parallel series. These
gas batteries being constantly supplied with newly formed gas produced by
elctrolysis generate a continuous current capable of producing electrolysis in
another apparatus without additional expense, for which purpose it is simply
necessary to connect the poles of the batteries with the electrodes of an apparatus
similar to that herein beforo described.
The oxygen and hydrogen generated in this apparatus may be conducted to the
first gas batteries, or be employed to supply other batteries capable of producing an
electrolysis of the third order.
In order to retain carbonate of soda it is necessary to saturate the concentrated
solution of caustic soda with carbonic acid prepared in the ordinary method.