Improvements in the Manufacture of Alkalies, and in Means applicable for use therein,
Year: 1898

page_text: .
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Alkalies, and in Means applicable
for use therein,
I, JAMES HARGREAVES, of Farnworth-in-Widnes, in the County of Lancaster,
Chemist, do hereby declare the nature of this invention to be as follows:-
This invention relates to the manufacture of alkalies by electrolysis, and con-
sists in certain improvements in the mode of treatment and in the means and
appliances employed; my objects being to increase the efficiency of the process
and to effect economy in the construction of the apparatus and in working.
In working with electrolytic cells of the type described in the Specification to
my Letters Patent dated 27th September, 1893, No. 18,173, I place in the cathode
chamber a series of strips formed of copper or other suitable metal, same extending
from the cover-plate to the surface of the cathode and inclining downwards.
These strips.or plates operate to direct the condensed vapour or other liquid against
the surface of the cathode and more completely and rapidly to wash away the
alkali as it is formed upon the said surface. For holding the inclined strips in
position upon the cover-plate, I bed the former in cement, the latter serving
the further purpose of a non-conductor and preventing loss of heat from the
cells. The inclined strips also serve to support the cathode in close contact with
the diaphragm. I form the lower edges of the inclined strips with suitable
serrations or openings so as to permit the steam and gases to pass freely over the
surface of the cathode.
With a view to rendering the contact between the cathode, and the diaphragm
more perfect, I subject the woven wire cathode to a rolling process with the
effect that the projecting parts of the wires, at the points where they cross one
another are flattened.
To purify the carbonic acid gas from sulphurous acid and other impurities, I
cause the gases (which may be the waste gases from gas engines, coal fires or
lime kilns) whilst in a heated state to be saturated with moisture and then cool
the said gases so as to effect the condensation of the moisture; the latter being
removed by causing the gases to traverse suitable scrubbers.
To avoid the presence of chlorate or hypochlorite in the electrolyte and to
prevent the complicated reactions, destruction of anodes, and loss of power caused
by their presence, I analyse the solution and add thereto sufficient hydrochlorie
acid to decompose the said chlorate or hypochlorite, the chlorine being liberated
from the hydrochloric acid without having any hydrochloric acid in excess.
Where the presence of carbonic acid mixed with the evolved chlorine is not
injurious, I add to the circulating electrolyte some organic substance, such for
example as sugar, sawdust or the like, for the purpose of deoxidising the chlorate
or hypochlorite.
In constructing the anode cell, instead of using stone or slate, I employ
Portland or other like cement and I provide an outside framing of iron or other
metal, the cement being cast therein. Or instead of cement alone, I fill up a

page_text: portion of the framing with bricks, stone or other suitable materials. To prevent
leakage, I saturate the filling material employed in the construction of the cell
with paraffin wax, pitch, tar or other substance adapted to fill up the pores of,
or the interstices between, the bricks or other filling material.
Improvements in the Manufacture of Alkalies, and in Means applicable
for use therein.
I, JANES HARGREAVES, of Farnworth-in-Widnes, in the County of Lancaster,
England, Chemist, 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:-
This invention relates to the manufacture of alkalies by electrolysis, and con-
sists in certain improvements in the mode of treatment and in the means and
appliances employed; my objects being to increase the efficiency of the process
and to effect economy in the construction of the apparatus and in working.
In the accompanying drawings, Fig. 1 is a partial longitudinal section and
side elevation of an electrolytic cell embodying my improvements. Figs. 2 and 3
are respectively a corresponding transverse section and a plan. Figs. 4 and 5
are respectively a longitudinal section and a plan of the left-hand end of Figs. 1
and 3 illustrating a modification; Figs. 6 and 7 being similar views illustrating
a further modification. Fig. 8 is an enlarged view in section of my improved
cathode.
According to the method of working illustrated in Figs. 1, 2 and 3 the electro-
lyte or brine solution is circulated through the cell; the weakened solution in
company with the chlorine flowing away from the cell into a receptacle for
separating the chlorine; the weakened solution being then strengthened by the
addition of salt and re-circulated through the cell. According to the methods
illustrated in Figs. 4 and 5, and in Figs. 6 and 7, dry or new solid salt is supplied
to a saturating vessel situated within the anode compartment of the cell.
In working with electrolytic cells of the type described in the Specification to
my Letters Patent dated 27th September, 1893, No. 18,173, and illustrated in
the accompanying drawings, I place in the cathode chamber a a series of strips b
formed of copper or other suitable metal, same extending from the cover-plate c
to the surface of the cathode d and inclining downwards. These strips or plates
operate to direct the condensed vapour or other liquid formed in the cathode
chamber against the surface of the cathode and more completely and rapidly
to wash away the alkali as it is formed upon the said surface of the cathode and
diaphragm. For holding the inclined strips in position upon the cover-plate,
I bed the former in cement e, the latter serving the further purpose of a non-
conductor of heat and preventing loss of heat from the cells. The inclined
strips also serve to support the cathode din close contact with the diaphragm.
I form the lower edges 61 of the inclined strips b with suitable serrations or
openings so as to permit the steam and gases to pass freely over the surface of
the cathode. aa are injectors for supplying carbonic acid gas and steam to
the cathode chambers a a.

page_text: In treating brine or salt solution, the strengthened brine enters the anode
chamber of the cell by way of the pipe g; the weakened or exhausted solution
together with the chlorine passing away through the pipe h to a well or receptacle
wherein the gas and weakened brine are separated. Salt is added to the latter
for strengthening the same whereupon it is again conducted through the cell by
way of the pipe g for re-treatment by the electric current.
When treating dry or new salt in a solid or crystal state, I employ within the
cell a saturating vessel or compartment i constructed according to either of the
alternative modes illustrated in Figs. 4 to 7 inclusive. In Figs. 4 and 5, this
vessel is of tubular form and is preferably elliptical in transverse section, its sides
being provided with perforations ¹. These perforations are preferably disposed
at an inclination as shown in Fig. 4 with a view to preventing the escape, previous
to the saturation of the electrolyte, of the salt into the anode compartment of
the cell. The saturating compartment & is charged through the charging aperture
formed by the pipe 22 which is arranged to enter the upper end of the saturating
compartment below the surface of the electrolyte and thereby prevent the escape
through the charging aperture of the chlorine generated in the cell. The upper
extremity of the charging aperture may moreover be luted or furnished with a
water-seal. According to the construction shown in Figs. 6 and 7 the saturating
compartment i is formed by placing transversely in the cell a number of slats
same being disposed at an inclination so as to form inclined transverse slits or
openings and serving a similar purpose to the inclined perforations in the
sides of the tube i. With a view to preventing the escape of chlorine, the roof
of the cell is formed with a depending flange which dips into the compartment i
below the surface of the electrolyte.
The tube and the slats 20 may be formed of earthenware, of slate or of tiles.
In using tiles as shown in Figs. 6 and 7 the ends may be embedded in cement as
at 3.
With a view to rendering the contact between the cathode and the diaphragm
more perfect, I subject the woven wire cathode to a rolling process with the
effect that the projecting parts of the wires at the points where they cross one
another are flattened, as shown in the enlarged fragmentary view, Fig. 8.
To purify the carbonic acid gas from sulphurous acid and other impurities, I
cause the gases (which may be the waste gases from gas engines, coal fires or
lime kilns) whilst in a heated state to be saturated with moisture and then cool
the said gases so as to effect the condensation of the moisture; the latter being
removed by causing the gases to traverse suitable scrubbers.
To avoid the presence of chlorate or hypochlorite in the electrolyte and to
prevent the complicated reactions, destruction of anodes, and loss of power caused
by their presence, I analyse the solution and add thereto sufficient hydrochlori
acid to decompose the said chlorate or hypochlorite, the chlorine being liberate:
from the hydrochloric acid without having any hydrochloric acid in excess.
Where the presence of carbonic acid mixed with the evolved chlorine is not
injurious, I add to the circulating electrolyte some organic substance, such, for
example, as sugar, sawdust or the like, for the purpose of deoxidising the chlorate
or hypochlorite.
To
In constructing the anode cell, instead of using stone or slate, I employ
Portland or other like cement and I provide an outside framing 7 of iron or other
metal, the cement being cast therein. Or instead of cement alone, I fill up a
portion of the framing with bricks, stone or other suitable material m.
prevent leakage, I saturate the filling material employed in the construction of
the cell with paraffin wax, pitch, tar or other substance adapted to fill up the
pores of, or the interstices between, the bricks or other filling material. The
framing is formed in three portions, the base and the end-pieces. The base
comprises a central space, forming a tray for the reception of the cement k, and
a channel upon either side thereof for conducting away the product from
the cathode chamber a. 1 are pipes for draining the channel A. The end-

page_text: pieces are secured by bolts to flanges formed on the base-plate. The upper
extremities of the end-pieces are provided with inclined surfaces 13 13 beneath
which work the wedges situated one at each end of the cell. These wedges
rest upon the upper surface of the end-walls of the cell and are connected
together by means of the tie-rods 15. Upon tightening the nuts pertaining
to the tie-rods the wedges are drawn towards each other with the effect that a
downward pressure is exerted upon the end-walls while maintaining the stability
of the roof; the form of the cell being hereby preserved. The cover-plates ce
are held in position by means of cramps
2. The cover-plates may be
protected by wooden planks with a view to preventing loss of heat from the
cathode chambers.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I claim :-
1. In the manufacture of alkalies by electrolysis, a series of inclined metal
strips or plates arranged in the cathode chamber of the cell and extending from
the cover-plate to the surface of the cathode, substantially as herein described.
and whereby the cathode is supported in close contact with the diaphragm, the
condensed vapour is directed against the surface of the cathode and the product
is more completely and expeditiously removed as it is formed upon the surface
of the cathode.
2. The herein described method of holding the inclined strips in position on
the cover-plate, same consisting in bedding the strips in cement; loss of heat
from the cell being hereby prevented.
3. In the manufacture of alkalies by electrolysis, a series of inclined metal
strips or plates arranged in the cathode chamber of the cell and extending from
the cover-plate to the surface of the cathode, the lower edges of the inclined strips
or plates being serrated so as to form openings for the free passage of the steam
and gases over the surface of the cathode, substantially as described.
4. In an electrolytic cell, a woven wire cathode having the projecting parts
of the wires where they cross one another flattened by rolling, substantially as
and for the purpose specified.
5. For use in the production of alkalies by electrolysis, the improved electro-
lytic cell constructed substantially as herein described and having the walls of
the anode compartment composed either wholly or in part of Portland cement
formed by casting in an external casing and preferably in conjunction with a
filling of brick, stone or similar material saturated with paraffin wax, pitch, tar
or the like.