Improvements in Process and Apparatus for Electrolytically Treating Salts in Solution or in Molten State.
Year: 1894

page_text: Date of Application, 10th July, 1894-Accepted, 22nd Sept., 1894
Improvements in Process and Apparatus for Electrolytically
Treating Salts in Solution or in Molten State.
1, PETER JENSEN of No. 77 Chancery Lane in the County of Middlesex Chartered
Patent Agent do hereby declare the nature of this invention (a communication to
me from abroad by Henrik Christian Fredrik Störmer of Zetlitz Gade No. 5
Christiania, Norway, Mechanical Engineer) 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 electrolytical processes, in which the positive and negative
electric field are separated from each other by means of a porous diaphragm in order
to prevent the mixing of the ions with each other.
By these processes as they are mostly carried out there exist several drawbacks,
from which reason the same are not considered to be economically advantageous
processes. One of these drawbacks is that the electrolytic resistance is considerably
increased through the diaphragm and another that the diaphragm does not
absolutely prevent reunion of the ions and hereto comes that the diaphragms
themselves are destroyed by the action of the chemical processes that take place
within the pores of the diaphragm.
The present invention has for its object a method in which the use of such
diaphragms is not associated with the above drawbacks, which method consists in
utilizing, so to say, a flowing liquid or molten substance as diaphragm for separating
the two electric fields from each other.
To make my invention better understood, I show in the annexed drawing an
apparatus which may be used when carrying out my improved process for instance
in the decomposition of common salt, chloride of sodium, in order to obtain
chlorine gas and caustic soda.
The drawing shows a schematical vertical cross section through this improved
apparatus. B is the vessel containing the electrolyte or solution to be treated-in
this case a solution of chloride of sodium. The shape material and arrangement of
the same differs according to the circumstances and it may be of a usual well-known
construction. If a salt in molten state is treated, it is made of fireproof material.
A is the anode and C the cathode; these are also of the usual construction and of a
material according to the treated substances; carbon electrodes being preferred for
the sake of their cheapness. The vessel B is divided in two compartments by
means of a hollow partition D; the latter may be carried above the upper edge of
the vessel or it may only reach underneath the cover of the vessel and in this latter
case the space of the partition wall communicates with a cistern placed at a higher
level or with pump arrangement.
The said hollow partition consists below the level of the solution of two thin
porous diaphragms M, of any material commonly used for such purposes; these
thin diaphragms may also consist of perforated plates. If a substance in molten
condition is being treated the diaphragms M are made of a fireproof material, such
as asbestos. E, E and F F' are inlet and outlet pipes for the solutions under
treatment. G and H are gas outlet pipes.
This apparatus works in the following manner. The solution or molten substance
to be treated is filled in the vessel and in the space in the diaphragm D there is
filled a liquid or a molten substance, so that there will exist an outward pressure in
the partition space.
The liquid will therefore pass out to both sides through the
diaphragms preventing thereby absolutely any wandering of the ions from one
compartment of the vessel to another. As partition liquid or "din-liquid is
"

page_text: advantageously used the electrolyte itself or a solution containing one constituent of
the electrolyte. The feeding of the electrolyte may then be done through the
hollow diaphragm, whereby the pipes E, E¹ are made superfluous and the whole
process greatly simplified. Also in case of treating a molten substance the same
may be fed to the vessel through the diaphragm.
Of course my invention may be carried out in the most different ways as to the
details of construction.
Having now particularly described and ascertained the nature the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In the electrolysis of salts in solution or in molten state the method for
preventing the wandering of the ions from the electro negative field to the electro
positive field and vice versa and the reunion of such ions in the diaphragm separating
the two fields of actions from each other, consisting in placing a liquid (or
eventually a molten substance) under pressure in a space between the said electric
fields, which space is separated from the electrode compartments by thin porous or
perforated walls, so that the fluid in the said hollow space will continuously pass out
to both sides through the pores of the diaphragmns.
2. In a process as described the feeding of the electrolyte through the hollow
diaphragm, thereby utilizing the electrolyte às separating fluid between the electrode
compartments.
3. In a process as described a hollow diaphragm or partition wall D provided
with porous or perforated membranes M and with an extension above the level of
the fluid in the vessel containing the electrodes or with a pipe connection to a
cistern situated at a higher level or to a pump.
4. The construction of apparatus as described with reference to the drawings.
Dd this 10th
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.