Improved Process and Apparatus for Dissociating Soluble Salts by Electrolysis.
Year: 1893

page_text: Date of Application, 12th Dec., 1893-Accepted, 20th Jan., 1894
COMPLETE SPECIFICATION.
Improved Process and Apparatus for Dissociating Soluble Salts by
Electrolysis.
I, REGINALD HADDAN; of the Firm of Herbert Haddan and Co. of
18 Buckingham Street, Strand, W.C. London, Patent Agent, do hereby declare
the nature of this invention a communication to me from abroad by Henry Spencer
Blackmore, of Mount Vernon, N.Y., United States of America, Chemist, and in
what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:—
This invention is based on the discovery that the dissociation of soluble salts
by electrolysis can be effected with great facility by providing a bath of
the electrolyte and two independent bodies of liquid, establishing a dialytic
communication between the bath and each of the independent bodies of liquid,
maintaining the independent bodies of liquid at a higher level than the level of the
bath, and passing a current of electricity through the independent bodies and
through the bath.
The apparatus which I have constructed for the purpose of carrying out the
invention is illustrated in the accompanying drawing in which,
Figure 1 represents a transverse vertical section in the plane xx Fig. 2.
Figure 2 is a plan or top view.
Figure 3 is a vertical longitudinal section in the plane y y Fig. 1, ou a smaller
scale than the previous figures.
Figure 4 is a sectional side elevation looking in the direction of arrow 3.
(Fig. 3).
In this drawing the letter A designates a tank which communicates with
a pipe a through which the electrolyte is introduced and also with a pipe b
which communicates with the tank by branch pipes 6' and serves to carry
away the surplus liquid so as to maintain a constant level of the liquid in
the tank A, such level being indicated by the dotted line 10 in Fig. 1. The
pipes a and b communicate with the tank Á at the same level and the pipe a may
run in a horizontal direction and be connected to the bottom part of a supply
tank T containing the electrolyte and extending above the level of the tank A as
shown in Fig. 4, or it may be connected to a pump or other equivalent device
suitable for the purpose of forcing the electrolyte through the pipe a into the
tank A. The surplus liquid which escapes though the pipe b need not be wasted
but it can be collected and fed into the tank A through the pipe a as indicated
in Fig. 4.
The tank A communicates with a tank B by means of a dialytic diaphragm D',
and in the example illustrated by the drawing these diaphragms extend down to
the bottom of the tank A.or nearly so, while the tanks B C extend below the
bottom of the tank A. E E' are two electrodes one of which is situated in the
tank B and the other in the tank C. These electrodes extend below the level of
the bottom edges of the dialytic diaphragms D D1 and they are provided with
upwardly pointed teeth or ridges e e'. The electrode E is secured to a cover or
dome 20 which is provided with an escape opening 23 and fits into a grooved
flange 21 secured in the interior of the tank and situated below the water line 11 so
that a liquid joint is formed which prevents the escape of gas from the interior of
the dome. The electrode E¹ is secured to a bar 22 which rests upon the top edge
of the tank C.
The tank B communicates through an opening or openings 24 with a trough F
which communicates with a water supply pipe 25 and is provided with an overflow

page_text: pipe 26 which extends up to the water line 11 so that if the supply pipe 25 is open,
the level of the water contained in the trough F and in the tank B will remain
constant at the line 11. The tank C connects by an opening or openings 27 with a
trough which is provided with a water supply pipe 28 and an overflow pipe 29.
which rises to the water line 11 so that if the water supply pipe 28 is open, the
level of the liquid in the tank C remains constant at the line 11. It will be
noticed that the line 10 which indicates the level of the liquid in the tank A
is somewhat lower down than the line 11 which indicates the level of the liquids
in the tanks B C. The object of this arrangement is to oppose the passage of
any portion of the electrolyte from the tank A through the diaphragms D D into
the tanks B C which is effected by the tendency of the liquids in the tanks B C to
flow into the tank A which tendency is imparted to them by reason of their higher
level.
If the tank A is charged with the solution of a salt such for instance as sodic
chloride while the tanks B C are filled with water to the levels indicated by the
lines 10 and 11 in Fig. 1 and a current of electricity is passed through the liquids
contained in the tanks, the chlorine migrates into the tank B and is liberated at
the electrode E, while the sodium migrates into the tank C where it combines
with oxygen, setting free hydrogen, and the solution of the ions can be withdrawn
by means of the stop-cocks 30, 31, and if a continuous stream of sodic chloride
solution is caused to pass through tank A while the level of the water in the
tanks BC is maintained by keeping the supply pipes 25 and 28 open, the solutions
of the ions can be withdrawn without interruption as long as the electric current is
maintained.
The gas set free in the tank B collects in the dome 20 and can be withdrawn by
means of the pipe and valve 23.
A hydrometer H and a scale is provided to indicate the height of the
concentrated solution which accumulates in the lower part of the tank C. The
electrodes E E¹ extend below the level of the bottom edges of the diaphragms D D',
but they terminate at some distance above the bottoms of the tanks B C, so that
room is left for the solutions of the ions to settle beneath said electrodes and
corrosion of the electrodes and of the diaphragms is obviated.
By means of the serrations e sharp edges or points are formed on the surfaces
of the electrodes whereby the electric action is facilitated and the danger that the
electrodes will split or become disintegrated is materially reduced or almost
entirely obviated.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The within described process for dissociating soluble salts into their acid and
basic constituents by electrolysis which consists in providing a bath of the
clectrolyte and two independent bodies of liquid, establishing a dialytic.com-
munication between the bath and each of the independent bodies of liquid,
maintaining the independent bodies of liquid at a higher level than the level of
the bath and passing a current of electricity through the independent bodies of
liquid and through the bath.
2. The within described process for dissociating soluble salts into their acid and
basic constituents by electrolysis which consists in providing a bath of the
electrolyte and two independent bodies of liquid, establishing a dialytic communi-
cation between the bath and each of the independent bodies of liquid, passing a
continuous stream of the electrolyte through the bath, maintaining the independent
bodies of liquid at a higher level than the level of the bath, passing a, current of
electricity through the independent bodies of liquid and through the bath and
withdrawing the solutions of the ions from the independent bodies of liquid while
the current of electricity is maintained.
3. The combination with the tanks A B C of dialytic diaphragms which form

page_text: the communications between the tank A and the tanks B C, electrodes EE
suspended in the tanks BC and means for maintaining the liquids in the
tanks B C at a higher level than that of the liquid in the tank A, substantially as
described.
4. The combination with the tank A, of two tanks B C which communicate
with the tank A through dialytic diaphragms and extend beneath the bottom
edges of said diaphragms, the supply pipe a, and discharge pipe b, communicating
with the tank A at the same level, the trough F communicating with the tank B,
the trough F¹ communicating with the tank C, the liquid supply pipes 25 and 28
leading into said troughs and the overflow pipes 26 and 29 rising in said troughs
to a level above the level of the supply pipe a and discharge pipe b, substantially
as described.
5. The combination with the tanks A B C, the dialytic diaphragms which form
communications between the tank A and tanks B C and the means for maintaining
the liquids in the tanks BC at a higher level than that of the liquid in the tank A,
of a dome 20 fitting into the top of the tank B, substantially as described.
6. The combination of the tank B, its dome 20 with its outlet 23, the serrated
electrode E, the trough f, the inlet and outlet pipes 25 and 26, communications 24,
outlet pipe and valve 30, the tank C, trough f¹, its inlet and outlet pipes 28
and 29, communications 24, the serrated electrode E¹ supported by the rod 23,
the hydrometer H with its scale 4, the outlet pipe and valve 31, the tank A
and situated between the tanks B C and
provided with inlet and outlet pipes a
the dialytic diaphragins D and D', substantially as described.
12. 19th dox of December 1893.
K. HADDAN.