Improvements in Diaphragms for Electrolytic Decomposing Apparatus.
Year: 1891

page_text: Date of Application, 14th Nov., 1891
Complete Specification Left, 11th Aug., 1892-Accepted, 1st Oct., 1892
PROVISIONAL SPECIFICATION.
Improvements in Diaphragms for Electrolytic Decomposing
Apparatus.
1, Dr. AUGUST BREUER, of Duisburg, in the Empire of Germany, do hereby
declare the nature of this invention to be as follows:-
In electrolytic decomposing apparatus it has generally been the custom to use,
instead of parchment paper, clay diaphragms, amongst other materials, especially
when a corrosive action of the electrolyte has been expected to take place.
When using such electrolytic decomposing apparatus it is found however, more
particularly in those cases in which corrosive substances are separated or formed,
such as in the decomposition of solutions of alkaline chlorides, that the clay
diaphragms soon lose their porosity and then they become useless.
Experiments have been made in order to obviate this inconvenience by the
employment of a permanently efficient diaphragm. These researches led to the
discovery of the fact that diaphragms made of a porous cement substance can be
used with advantage. It was also ascertained that porous cement-substances, used
as diaphragms in electrolytic decomposing apparatus, withstood chemical action and
were not even attacked by chlorine, and thus in contradistinction to clay
diaphragms they retained their porosity and consequently their usefulness.
The employment of such porous cement substances as diaphragms enables the
electrolytic decomposition of compounds which separate caustic or corrosive
substances. The above-mentioned cement substances may be made of either natural
or artificial cement or from lime or magnesia cements.
Such porous cement diaphragms may be readily obtained by giving the desired
form to a mixture of cement and porous resistant substances such as pumice stone,
or, by mixing the cement with soluble substances which are dissolved out during or
after the setting of the cement and thus leave the cement substance in a porous
state. The cement may also be mixed with a concentrated solution of salt from
which it withdraws the water of solution, whereby the salt is again lixiviated after
the cement has set or is dissolved in the electrolyte or in the lye which is to be
electrolyzed or has been more or less electrolyzed. Substances may also be added
to the cement which are destroyed or decomposed by the lye, the cement diaphragın
being left in a porous condition, as is the case with organic substances.
When these porous diaphragms are made from cement in any manner they
invariably possess the property of resisting the action of caustic or corrosive
substances, or of chlorine, and of preserving their porosity in electrolytic
decomposing apparatus. Such substances are easily produced in any form as plates,
cylinders, or the like by the means which are usually employed in the manufacture
of cements.
DL: 14th Jaw of November 1801

page_text: "
COMPLETE SPECIFICATION.
Improvements in Diaphragms for Electrolytic Decomposing
Apparatus.
I, Dr. August BREUER, of Duisburg, in the Empire of Germany, 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:—
In electrolytic decomposing apparatus it has generally been the custom to use,
instead of parchment paper clay diaphragms amongst other materials, especially
when a corrosive action of the electrolyte has been expected to take place.
In the use of such electrolytic decomposing apparatus it is found, however, more
particularly in those cases in which corrosive substances are separated or formed,
such as in the decomposition of solutions of alkaline chlorides, that the clay
diaphragms soon lose their porosity and therefore cease to be useful.
Experiments have been made in order to obviate this inconvenience by the
employment of a permanently efficient diaphragm. These researches led to the
discovery of the fact that diaphragms made of a porous cement substance can be
used with advantage. It was also ascertained that porous cement substances used
as diaphragms in electrolytic.decomposing apparatus withstood chemical action and
were not even attacked by chlorine, and thus in contradistinction to clay
diaphragms they retained their porosity and consequently their usefulness.
The employment of such porous cement substances as diaphragms enables the
electrolytic decomposition of compounds which separate caustic or corrosive
substances. The above-mentioned cement substances may be made of either,
natural or artificial cement, or from lime or magnesia cements.
Such porous cement diaphragms may be readily obtained by giving the desired
form to a mixture of cement and porous resistant substances such as pumice stone,
or by mixing the cement with soluble substances which are dissolved out during or
after the setting of the cement and thus leave the cement substance in a porous
state. The cement may also be mixed with a concentrated solution of salt from
which it withdraws the water of solution, whereby the salt is again lixiviated after
the cement has set or is dissolved in the electrolyte or in the lye which is to be
electrolyzed or has been more or less electrolyzed. Substances may also be added
to the cement which are destroyed or decomposed by the lye, the cernent diaphragm
being left in a porous condition, as is the case with organic substances.
The following examples may be mentioned for this:
First. Sifted pieces of pumice stone or coke of from 4 to 8 millimetres thick are
carefully mixed with natural or artificial cement, such as lime or magnesia cement,
in equal proportious, diluted with water to form a thick paste and put in moulds.
After setting the moulded pieces can be used. The thickness of the pieces of
pumice-stone or coke depends on the thickness of the moulded pieces to be obtained,
the pieces of pumice stone or coke mentioned in this example are suitable for the
manufacture of plates of from 12 to 15 millimetres thick.
Second. 35 litres of reduced rock-salt are mixed with 65 litres of natural or
artificial cement, such as lime or magnesia cement, diluted with water to form a
thick paste, and put in moulds. In lieu of rock-salt use may be made of other
soluble salts. After setting the moulded pieces or plates are lixiviated with
water.
Third. 50 litres of natural or artificial cement such as lime or magnesia cement,
are intimately mixed with 36 litres of a solution of rock-salt, which contains about
250 grammes of rock salt per litre, and 14 litres of hydrochloric acid, whereupon I
proceed as stated in the second example. The solution of rock-salt can be replaced
by other solutions of metallic salt, and the hydrochloric acid by other (inorganic or
organic) acids.

page_text: Fourth. 100 litres of natural or artificial cement such as lime or magnesia cement,
are intimately mixed with 2 kilogrammes of cow hair or woollen yarn cut to pieces,
diluted to form a thick paste and put in moulds. Such moulded pieces or plates
possess after they are set such a porosity that in the use of the same a greater
resistance to the current does not occur; in use the hair or the woollen fibres are
then gradually dissolved in the liquor, thereby rendering the plates still more
porous.
When these porous diaphragms are made from cement in any manner they
invariably possess the property of resisting the action of caustic or corrosive
substances, or of chlorine, and of preserving their porosity in electrolytic
decomposing apparatus. Such substances are easily produced in any form as plates,
cylinders, or the like by the means which are usually employed in the manufacture
of cements.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. The hereinbefore described diaphragms for electrolytic decomposing apparatus,
composed of porous cement substances as above set forth.
2. The process of manufacturing the hereinbefore described diaphragms consisting
of either mechanically mixing cement with porous substances resistant to the action
of caustic alkali and chlorine, or by adding to the cement any soluble material such
as soluble salts, vegetable fibre, hair, organic or inorganic acids, which may after-
wards be dissolved by a suitable agent or by the electrolyte, so as to leave the
cement diaphragms in a porous state.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.