Improved Diaphragm for Electrolytic Apparatus.
Year: 1898

page_text: Date of Application, 13th July, 1898-Accepted, 1st Oct., 1898
Communicated om abroa oy MRICH LANGGUTH, ΟΙ INNO. 03, Tempiergraben
Aachen, Germany, Mining Engineer.]
Improved Diaphragm for Electrolytic Apparatus.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 322, High Holborn, in the County of Middlesex, 6, Lord Street,
Liverpool, and 6, Bank Street, Manchester, both in the County of Lancaster, and
Lower Temple Street, Birmingham, in the County of Warwick, Civil Engineer,
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 follow-
ing statement:-
-
The present invention relates to an improved diaphragm for electrolytic appa-
ratuses
The construction of a thoroughly satisfactory diaphragm for electrolytic pur-
poses, and especially for the electrolysis of the alkalies still remains a much
desired requirement.
The present invention is devised to supply this want and to furnish a suitable
diaphragm which itself acts as a so-called bi-polar electrode. This diaphragm is
water tight and gas tight, it is not attacked by the electrolyte nor by the pro-
ducts produced in the operation, and offers little resistance to the passage of
the current.
My improved diaphragm consists essentially of a net work or grating of iron,
nickel, cobalt, copper or other suitable metals. The open spaces of this diaphragm
are completely closed with an amalgam of copper, lead, silver or other suitable
metals, according to the nature of the electrolyte. The aforesaid amalgam,
which must contain an excess of free quicksilver, is applied to the net or grating
in the warm state and of a pasty consistency; it completely fills the openings of
the grating or net work. When the mass cools, it hardens and forms one solid
whole in the form of a thick plate, which is well supported by the net-work or
grating passing through it.
The plates are secured in frames and when placed in the trough form the im-
penetrable divisions between the anode and the cathode cells. The mode of
operation of these bi-polar electrodes varies according to the various electrolytes
to be operated on. Taking by way of example solution of chloride of potassium,
the action will be as follows, reference being made to the accompanying drawing,
Figures 1 and 2. The bi-polar electrode c divides the anode space a from the
cathode space k of the tank b. The former space is filled with a solution of
chloride of potassium and the latter space with dilute caustic potash. When
electrolysis takes place, chloride of potassium is added gradually to the anode
cell. The chlorine escapes at the anode and is further treated in a suitable
manner. The potassium passes to the bi-polar electrode and there combines with
the free quicksilver to form a potassiumi amalgam. In the cathode space a
caustic potash decomposition takes place. The potassium passes to the cathode

page_text: and forms, by secondary decomposition of water, caustic potash (KOH). The
ion HO travels to the bi-polar electrode. As it possesses the greatest possible
affinity for the potassium of the potassium and copper amalgam there will be
formed at the wall of the bi-polar electrode in the cathode space KOH, con-
sequently, the quick-silver will be regenerated and enabled to take up a fresh
quantity of potassium. The bi-polar electrode consequently acts as a quick-silver
partition placed upright. The potassium of the decomposed potassic chloride
travels through it from the anode into the cathode space; nevertheless, the
diaphragm remains gas and water tight continuously The result of the elec-
trolysis is the liberation of chlorine in the anode space and the collection and
production of strong potash lye in the cathode space. Similar processes take
place in the decomposition of other alkalies.
my
Having now particularly described and ascertained the nature of said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is :—
1. The use in the electrolysis of alkalies of a bi-polar electrode acting as a
diaphragm constructed of copper, silver or lead amalgam in the form of dense
plates, prepared by inserting the amalgam in the apertures of a grating or net of
nickel, cobalt, iron, copper or the like.
2. The improved diaphragm constructed substantially as described and shewn
in the accompanying drawing.
Doted this 12th day of Tuly 1900
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant.