Manufacture of the Alkaline Carbonates or Bicarbonates by the Electrolytic Decomposition of Alkaline Chlorides in the presence of Gelatinous Alumina or Chloride or other Salt of Aluminium.
Year: 1892

page_text: Date of Application, 4th Apr., 1892
Complete Specification Left. 22nd Dec., 1892-Accepted, 11th Feb., 1893
PROVISIONAL SPECIFICATION.
Manufacture of the Alkaline Carbonates or Bicarbonates by the
Electrolytic Decomposition of Alkaline Chlorides in the presence
of Gelatinous Alumina or Chloride or other Salt of Aluminium.
We, EUGENE HERMITE, and ANDRÉ DUBOSc, both of No. 4 Rue Drouot,
Paris, France, do hereby declare the nature of this invention to be as follows:-
The different processes proposed up to the present time for obtaining alkalis or
the alkaline carbonates or bicarbonates by electrolytic decomposition of the alkaline
chlorides have not given satisfactory industrial results for the following reason:-
When a solution of an alkaline chloride such as chloride of sodium is subjected
to electrolytic action in a vessel with or without a partition, there is first obtained,
at the positive pole, chlorine, and at the negative pole sodium, which, in at once
decomposing the water by chemical reaction, produces soda. If the quantity of
this soda be determined as it is produced, it will be found that the quantity obtained
is much less than that indicated by the electro chemical theory, for the intensity of
current used. This loss of yield is due to the following causes :
The combining heat of Na O is less than that of Na Cl; it follows that a
current the electromotive force of which is sufficient to decompose Na Cl will,
a fortiori, be sufficient to decompose Na O. Consequently the Na O enters in the
circuit as electrolyte from the time of its production and, conformably with the law
of Faraday, Na O is decomposed by the current at the same time as Na Cl, pro-
It follows that, on
portionately to its electro chemical equivalent and to its mass.
the one hand the current produces soda in decomposing Na Cl, but on the other
hand it decomposes the soda as soon as produced. Consequently the electromotive
force is uselessly expended.
On the other hand if in its nascent state, the Na O produced be made to enter
into a sodic combination, the combining heat of which is higher than that of Na Cl,
the electromotive force of the current, being constant and equal to the force
required for decomposing Na Cl, will no longer act upon the new sodic compound.
Na Cl will remain the sole electrolyte, and the sodic combination obtained by the
secondary reaction will remain a dielectric, and its quantity will continue to increase
in proportion to the decomposition of Na Cl, the electromotive force remaining the
same as at the commencement of the operation, that is to say, equal to the electro-
motive force required for effecting the decomposition of the Na Cl.
Having thus stated the principle of our invention we will now describe .the
manner of carrying it into practice.
If gelatinous alumina be put in the presence of an alkali, a combination of the
two bodies ensues, and alkaline aluminate is formed, the combining heat of which
We therefore add
is higher than that of the alkaline chlorides or of the alkalis.
to an alkaline chloride in solution a quantity of pure gelatinous alumina, sufficient
for combining with the total quantity of alkali contained in the chloride, in forming
an alkaline aluminate, and we subject the liquid thus prepared to electrolytic action
by means of a current, the electromotive force of which is sufficient to decompose the
alkaline chloride. The alkali set free at the negative pole combines, as soon as
formed, with the alumina for producing in its turn an alkaline aluminate, while the Cl
Bet free at the positive pole is driven off and is employed for the production of
hypochlorites, or for other purposes. When the whole of the alkaline chloride has
been decomposed, the electric current is stopped and a current of carbonic acid gas is
5 passed through the liquor, which combines with the alkali for giving an alkaline
carbonate or bicarbonate, while the alumina is precipitated in the form of gelatinous
alumina which can serve for a fresh operation.

page_text: Instead of adding alumina to the solution of alkaline chloride, there may be used
chloride or other salt of aluminium; the freed alkali then precipitates the alumina in
forming an alkaline chlorate; when all the alumina of the Al C has been pre-
cipitated, the formation of the alkaline aluminate commences and continues as
previously described.
Dated this 4th day of April 1899
ABEL & IMRAY,
Agents for the Applicants."
COMPLETE SPECIFICATION.
Manufacture of the Alkaline Carbonates or Bicarbonates by the
Electrolytic Decomposition of Alkaline Chlorides in the presence
of Gelatinous Alumina or Chloride or other Salt of Aluminium.
We, EUGENE HERMITE, and ANDRÉ DUBOSC, both of No. 4 'Rue Drouot,
Paris, France, Manufacturers, do hereby declare the nature of this invention and
in what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement:-
The different processes proposed up to the present time for obtaining alkalis or
the alkaline carbonates or bicarbonates by electrolytic decomposition of the alkaline
chlorides have not given satisfactory industrial results for the following reason:-
When a solution of an alkaline chloride such as chloride of sodium is subjected
to electrolytic action in a vessel with or without a partition, there is first obtained,
at the positive pole, chlorine, and at the negative pole sodium, which, in at once
decomposing the water by chemical reaction, produces soda. If the quantity of
this soda be determined as it is produced, it will be found that the quantity
obtained is much less than that indicated by the electro chemical theory, for
the intensity of current used. This loss of yield is due to the following causes :
The combining heat of Na O is less than that of Na Cl; it follows that a current
the electromotive force of which is sufficient to decompose Na Cl will, a fortiori, be
sufficient to decompose Na O. Consequently the Na O enters in the circuit as
electrolyte from the time of its production and conformably with the law of
Faraday, Na O is decomposed by the current at the same time as Na Cl, pro-
portionately to its electro chemical equivalent and to its mass. It follows that,
on the one hand the current produces soda in decomposing Na Cl, but on the other
band it decomposes the soda as soon as produced. Consequently the electromotive
force is uselessly expended.
On the other hand if in its nascent state, the Na O produced be made to enter
into a sodic combination, the combining heat of which is higher than that of Na CL,
the electromotive force of the current being constant and equal to the force
required for decomposing Na Cl, will no longer act upon the new sodic compound.
Na Cl will remain the sole electrolyte, and the sodic combination obtained by the
secondary reaction will remain a dielectric, and its quantity will continue to increase
in proportion to the decomposition of Na Cl, the electromotive force remaining the
same as at the commencement of the operation, that is to say, equal to the electro-
motive force required for effecting the decomposition of the Na Cl.
Having thus stated the principle of our invention we will now describe the
manner of carrying it into practice.
If gelatinous alumina be put in the presence of an alkali, a combination of the
two bodies ensues, and alkaline aluminate is formed, the combining heat of which
is higher than that of the alkaline chlorides or of the alkalies. We therefore add
to an alkaline chloride in solution a quantity of pure gelatinous alumina, sufficient
for combining with the total quantity of alkali contained in the chloride, in forming
an alkaline aluminate, and we subject the liquid thus prepared to electrolytic
action in a partitioned vessel by means of a current, the electromotive force of
which is sufficient to decompose the alkaline chloride. The alkali set free at the

page_text: When
negative pole combines, as soon as formed, with the alumina for producing in its
turn an alkaline aluminate, while the Cl set free at the positive pole is driven off
and is employed for the production of hypochlorites, or for other purposes.
the whole of the alkaline chloride has been decomposed, the electric current is
stopped and a current of carbonic acid gas is passed through the liquor, which
combines with the alkali for giving an alkaline carbonate or bicarbonate, while
the alumina is precipitated in the form of gelatinous alumina which can serve for a
fresh operation.
Instead of adding alumina to the solution of alkaline chloride, there may be
used chloride or other salt of aluminium, the freed alkali then precipitates the
alumina in forming an alkaline chloride; when all the alumina of the Al' Cl³ has
been precipitated, the formation of the alkaline aluminate commences and continues
as previously described.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. The herein described process for preparing alkaline aluminates by subjecting
alkaline chlorides to electrolytic action in presence of gelatinous alumina or
aluminium chloride or other salts of aluminium.
2. The herein described process for manufacture of alkaline carbonates or
bicarbonates by treating with carbonic acid alkaline aluminates electrolytically
prepared as above, and for recovery of the alumina available for subsequent
preparation of the said aluminates.
Dated this 22nd day of December 1892.
ABEL & IMRAY,
Agents for the Applicants.