ELECTROLYSIS APPARATUS
[TECHNICAL FIELD]
[0001] The present invention relates to an electrolysis apparatus and, more particularly,
to an electrolysis apparatus having an evaporation restraining member.
[BACKGROUND ART]
[0002] In recent years, an electrolysis apparatus has been proposed for melting metal compound
such as zinc chloride or the like to carry out electrolysis of the same for producing
metal such as zinc or the like. With such an electrolysis apparatus, metal compound,
filled in a crucible (electrolysis cell) made of graphite, is heated up to a temperature
above a melting point of meal to obtain electrolyte. Then, applying electric current
electrodes immersed in the resulting electrolyte enables electrolyte to be decomposed
respectively into compound such as chloride and metal such as zinc.
[0003] With such an electrolysis apparatus, heating metal compound to a temperature beyond
the melting point of metal results in the production of metal compound gas. If zinc
chloride is heated to a temperature of, for instance, 400°C higher than a melting
point of zinc by a value of approximately 50°C, then a part of zinc chloride is gasified
from a liquid surface of melted zinc chloride and such gasified zinc chloride rises
in the electrolysis apparatus to be cooled in an area above the liquid surface of
electrolyte. This causes a large amount of electrolyte mist to be generated. Such
electrolyte mist is adhered onto an inner wall of an exhaust pipe for exhausting by-product
gas, thereby causing a possibility to occur with an issue of clogging the exhaust
pipe.
[0004] Japanese Patent Application Laid-Open Publication
2005-200758 discloses an electrolysis cell structure body, comprised of an air space provided
in an area above a liquid surface of electrolyte to cause by-product gas to convect,
and a gas exhaust tube provided above such an air space. A temperature of the spacing
at an upper area of the air space is set to be lower than a temperature of electrolyte
to cause by-product gas and electrolyte mist to convect in the air space, causing
electrolyte mist to drop into electrolyte to allow only by-product gas to be delivered
to the exhaust pipe.
[DISCLOSURE OF INVENTION]
[Technical Problem]
[0005] However, upon studies conducted by the present inventors, with such a structure disclosed
in Japanese Patent Application Laid-Open Publication
2005-200758, when heating electrolyte at a higher temperature, the amount of evaporated electrolyte
increases. In this case, there is a certain limitation in causing electrolyte mist
to drop into electrolyte by causing by-product gas and electrolyte mist to convect
in the air space.
[0006] Meanwhile, if the temperature for heating metal compound set at a lower level to
lower the temperature of electrolyte, the amount of evaporated electrolyte can be
reduced. However, the lower the temperature of electrolyte, the higher will be a voltage
required for electrolysis and the greater will be liquid resistance of electrolyte
with a resultant increase in electric power needed for electrolysis. Further, the
low temperature results in an increase in viscosity of electrolyte and an electrolysis
product is separated from electrode surfaces at slow speeds with a resultant difficulty
of efficiently continuing electrolysis reaction. That is, there is a certain limitation
in setting the temperature for heating metal compound to be lowered to maintain electrolyte
at the lowered temperature.
[0007] The present invention has been completed with the above studies conducted by the
present inventors in mind and has an object of the present invention to provide an
electrolysis apparatus that can minimize the amount of evaporated electrolyte and
prevent the occurrence of the clogging of an exhaust pipe without lowering a temperature
of electrolyte.
[Technical Solution]
[0008] To solve the above issues, one aspect of the present invention provides an electrolysis
apparatus comprising an electrolysis cell accommodating therein electrolyte, a heating
section located around the electrolysis cell to heat the electrolysis cell, an electrode
section having an electrode unit immersed in the electrolyte and a power-conducting
electrode portion supporting the electrode unit to apply the electrode unit with electric
power, a lid body defining a space region in an area above the electrolysis cell,
an exhaust section located in the lid body to allow the space region to communicate
with an outside for exhausting by-product gas, resulting from electrolysis of the
electrolyte, from the space region to the outside, and an evaporation restraining
member floating on a liquid surface of the electrolyte so as to cover the liquid surface
of the electrolyte for permitting the by-product gas, resulting from electrolysis
of the electrolyte, to escape to the space region while restraining the electrolyte
from evaporating.
[Advantageous Effects]
[0009] With the electrolysis apparatus of one aspect of the present invention, the amount
of evaporated electrolyte can be decreased and the clogging of an exhaust pipe can
be avoided without lowering a temperature of electrolyte.
[BRIEF DESCRIPTION OF DRAWINGS]
[0010]
FIG. 1 is a cross-sectional view of an electrolysis apparatus of a first embodiment
according to the present invention.
FIG. 2 is a view as viewed in a Z-direction of FIG. 1 and represents an enlarged top
view of an evaporation restraining member used in the present embodiment.
FIG. 3 is an enlarged cross-sectional view taken on line A-A of FIG. 1.
FIG. 4 is a cross-sectional view of an electrolysis apparatus of a second embodiment
according to the present invention.
FIG. 5 is a view as viewed in the Z-direction of FIG. 4 and represents an enlarged
top view of an evaporation restraining member used in the present embodiment.
FIG. 6 is an enlarged cross-sectional view taken on line B-B of FIG. 4.
FIG. 7 corresponds to a positional relationship of FIG. 5 and represents an enlarged
top view of an evaporation restraining member of a modified form of the present embodiment.
FIG. 8 corresponds to a positional relationship of FIG. 5 and represents an enlarged
top view of an evaporation restraining member of another modified form of the present
embodiment.
FIG. 9 is a cross-sectional view of an electrolysis apparatus of a third embodiment
according to the present invention.
FIG. 10 is a view as viewed in the Z-direction of FIG. 9 and represents an enlarged
top view of an evaporation restraining member used in the present embodiment.
FIG. 11 is an enlarged cross-sectional view taken on line C-C of FIG. 10.
FIG. 12 corresponds to a positional relationship of FIG. 11 and represents an enlarged
top view of an evaporation restraining member of a modified form of the present embodiment.
FIG. 13 corresponds to a positional relationship of FIG. 11 and represents an enlarged
top view of an evaporation restraining member of another modified form of the present
embodiment.
[BEST MODE FOR CARRYING OUT THE INVENTION]
[0011] Now, electrolysis apparatuses of various embodiments according to the present invention
will be described below with reference to the accompanying drawings. Throughout the
drawings, an x-axis, a y-axis and a z-axis represent a three-axis orthogonal coordinate
system with the z-axis having a positive direction referred to as an upper direction
and a negative direction referred to as a lower direction.
(First Embodiment)
[0012] First, the electrolysis apparatus of a first embodiment according to the present
invention will be described below in detail.
[0013] FIG. 1 is a cross-sectional view of the electrolysis apparatus of the present embodiment.
Further, FIG. 2 is an enlarged top view of FIG. 1, as viewed in the Z-direction that
is parallel to the z-axis, for representing an evaporation restraining member forming
part of the electrolysis apparatus of the present embodiment. FIG. 3 is an enlarged
cross-sectional view taken on line A-A of FIG. 1.
[0014] As shown in FIG. 1, the electrolysis apparatus 1 of the present embodiment includes
an electrolysis cell 10, a heating section 20, an electrode section 30, a lid body
45, an exhaust section 50 and an evaporation restraining member 60.
[0015] The electrolysis cell 10 is a cylindrical member, made of graphite, which is bottomed
for internally accommodating electrolyte 70 composed of melted metal compound such
as zinc chloride or the like. The electrolysis cell 10 has an inner surface 10a, coated
with a glass-like carbon layer, with which electrolyte 70 is held in contact. The
electrolysis cell 10 has, for instance, an inner diameter d1 of 400mm with a wall
thickness t1 of 20 mm.
[0016] The heating section 20 is a bottomed cylindrical member located around the electrolysis
cell 10 so as to surround the same. The heating section 20 has an upper end formed
in an open end that is folded inward to be brought into contact with an outer wall
10b of the electrolysis cell 10 at an upper open end thereof to fixedly retain the
electrolysis cell 10. Further, the electrolysis cell 10 has the open end protruding
upward from a contact position with the heating section 20.
[0017] The heating section 20 heats and melts the metal compound accumulated in the electrolysis
cell 10 to form electrolyte 70. Electrolyte 70 is maintained at a given temperature
to reduce liquid resistance and when electrolyte 70 includes, for instance, zinc chloride,
electrolyte 70 is maintained at a temperature of approximately 550°C.
[0018] The electrode section 30 supplies electric current to electrolyte 70 for making electrolysis
of electrolyte 70. The electrode section 30 includes an electrode unit 30a entirely
immersed in electrolyte 70, and a power-conducting electrode portion 30b.
[0019] The electrode unit 30a takes the form of a structure comprised of a plurality of
plate-like graphite electrodes 33 unitarily juxtaposed by given distances on a ceramic
base member 35 made of alumina to be fixedly retained in place. The electrode unit
30a is of a bipolar type formed in an electrode pair in which adjacent ones of the
plurality of plural electrodes 33 have different polarities but may be of a unipolar
type.
[0020] The power-conducting electrode portion 30b are a pair of columnar electrode bars
each made of iron and each covered with a protector tube (not shown) made of mullite.
The pair of iron electrode bars 37 is connected to the electrodes 33 on both sides
of the electrode unit 30a.
[0021] The lid body 45 includes a cylindrical member with an upper portion being closed
and is located on the electrolysis cell 10 at an upper portion thereof. The lid body
45 has a lower end portion formed with an open end portion having an inner surface
45a kept in contact with the outer wall 10b protruding upward from a contact area
held in contact with the heating portion 20 of the electrolysis cell 10. The lid body
45 and the outer wall 10b are hermetically sealed with each other by means of a seal
member (not shown) such that the lid body 45 and the electrolysis cell 10 are formed
in a unitary structure. This allows the electrolysis cell 10 to have an upper area
formed with a space region 40 in a closed space. In addition, the lid body 45, closing
an upper area of the space region 40, has a top surface portion formed with a pair
of through-bores through which the pair of electrode bars 37 is inserted.
[0022] The exhaust section 50 includes an exhaust pipe 53 connected to the top surface portion,
closing the upper area of the space region 40, of the lid body 45 at an area apart
from the area in which the electrode bars 37 are inserted, and a filter 57 fitted
in the exhaust pipe 53.
[0023] The exhaust pipe 53 is connected to an exhaust system (not shown) to allow by-product
gas, generated during electrolysis of electrolyte 70, to be exhausted from the space
region 40 to the outside through the exhaust system.
[0024] As shown in FIGS. 2 and 3 in detail, the evaporation restraining member 60 is placed
on a liquid surface of electrolyte 70 in a floating state so as to cover a nearly
greater part of the liquid surface of electrolyte 70. More particularly, the evaporation
restraining member 60 is comprised of a circular plate-like member, having a pair
of vertically extending first through-bore 60a, and a plurality of vertically extending
second through-bores 60b.
[0025] The evaporation restraining member 60 is shaped in a plate-like configuration similar
to a shape of the open end of the electrolysis cell 10 because of enabling the plate-like
configuration to cover the greater portion of the liquid surface of electrolyte 70
and, hence, comprised of the circular plate-like member. However, the present invention
is not limited to such a configuration and the evaporation restraining member 60 may
take a variety of shapes depending on a structure, such as a rectangular shape, of
the electrolysis cell 10 at the open end thereof.
[0026] Under a circumstance where electrolyte 70 is melted liquid of zinc chloride, further,
the evaporation restraining member 60 may be preferably made of graphite on the standpoint
of tolerance and specific gravity against electrolyte 70. By so doing, the evaporation
restraining member 60 can be reliably placed on the liquid surface such that the evaporation
restraining member 60 partly protrudes from the liquid surface of electrolyte 70 in
a floating state.
[0027] The pair of first through-bores 60a is formed in circular holes, penetrating upper
and lower surfaces of the evaporation restraining member 60, through which the pair
of electrode bars 37 is inserted. Each of the through-bores 60a has an opening diameter
d2 that is greater than a diameter d4 of each electrode bar 37 involving the protector
tube. The pair of electrode bars 37 is fixed to a support body (not shown) in an area
above the evaporation restraining member 60 and connected to a D.C power supply (not
shown).
[0028] The plurality of second through-bores 60b are formed in circular holes, penetrating
the upper and lower surfaces of the evaporation restraining member 60 so as to allow
a part of the liquid surface of electrolyte 70 to be exposed to the space region 40,
which are formed in given distances in a cyclic pattern as to the x-y plane. As observed
in the direction of the z-axis, the evaporation restraining member 60 is disposed
so as to cover the electrode unit 30a immersed in electrolyte 70. Thus, the plurality
of second through-bores 60b of the evaporation restraining member 60 are necessarily
disposed in a region involving a projection geometry, projected onto the evaporation
restraining member 60, of the electrode unit 30a which is immersed in electrolyte
70.
[0029] Each of the first through-bores 60a has an opening diameter d2 of, for instance,
60mm and each of the second through-bores 60b has an opening diameter of, for instance,
20mm. Further, each of the electrode bars 37, involving the protector tube, has a
diameter d4 of 50mm. In addition, the evaporation restraining member 60 has an outer
diameter of, for instance, 90mm with a thickness t2 of 5mm.
[0030] Here, electrolyte mist is present in the space region 40 at a rate varying in proportion
to the amount of evaporated electrolyte 70. In addition, the amount of evaporated
electrolyte 70 varies in proportion to a surface area of a liquid phase relative to
a gas phase when the liquid phase and the gas phase are held in contact with each
other, i.e. in proportion to a surface area in which the liquid surface of electrolyte
70 is held in direct contact with the space region 40.
[0031] Therefore, the evaporation restraining member 60 is placed on the liquid surface
of electrolyte 70 so as to cover the greater part of the liquid surface of electrolyte
70 in the floating state with a part of the liquid surface of electrolyte 70 being
exposed to the space region 40 via the second through-bores 60b. With such a structure
being adopted, even if a temperature of electrolyte 70 reaches high temperatures,
the amount of evaporated electrolyte 70 can be reduced while appropriately permitting
by-product gas, generated upon electrolysis of electrolyte 70, to escape to the space
region 40.
[0032] Further, the evaporation restraining member 60 is placed on the liquid surface of
electrolyte 70 in the floating state. Even if the liquid surface moves upward or downward
depending on an increment or decrement of electrolyte 70, the evaporation restraining
member 60 can cover the liquid surface of electrolyte 70 following the movement thereof.
This allows the liquid surface to have a minimized exposed surface area, reliably
decreasing the amount of evaporated electrolyte 70.
[0033] With the structure of the present embodiment, therefore, applying the evaporation
restraining member 60 reliably enables a reduction in the amount of evaporated electrolyte
70 while realizing electrolysis reaction with high efficiency at high temperatures.
[0034] Further, the liquid surface of electrolyte 70 is appropriately exposed to the space
region 40 via the second through-bores 60b. This allows by-product gas, generated
following electrolysis of electrolyte 70, to escape through the second through-bores
60b to the space region 40, reliably enabling the suppression of a situation under
which by-product gas undesirably remain in a lower area of the evaporation restraining
member 60.
[0035] At the same time, a reduction occurs in the amount of evaporated electrolyte 70 while
achieving a reduction in a heat discharge rate of electrolyte 70. This results in
an increase in a heat retention effect of electrolyte 70 to enable the heat section
20 to have improved heating efficiency.
[0036] Further, the reduction occurs in the amount of evaporated electrolyte 70 and the
rate of generating electrolyte mist is decreased. This allows the filter 57 to be
less subjected to the occurrence of electrolyte mist adhered thereto to minimize a
risk of clogging. This enables by-product gas such as, for instance, chlorine gas,
generated in electrolysis of electrolyte 70 to be efficiently exhausted from the space
region 40, resulting in improvement in safety of the electrolysis apparatus.
[0037] Incidentally, in case that the power-conducting electrode portion 30b is not provided
to extend above the electrode unit 30a but provided to extend laterally to or beneath
the electrode unit 30a, of course, it is not needed that the pair of first through-bores
60a is formed in the evaporation restraining member 60, and such a situation is applicable
to the following embodiments.
(Second Embodiment)
[0038] Next, an electrolysis apparatus of a second embodiment according to the present invention
will be described below in detail with reference to the accompanying drawings.
[0039] FIG. 4 is a cross-sectional view of the electrolysis apparatus of the present embodiment.
Further, FIG. 5 is an enlarged top view of FIG. 4, as viewed in the Z-direction that
is parallel to the z-axis, for representing an evaporation restraining member used
in the present embodiment. Furthermore, FIG. 6 is an enlarged cross-sectional view
taken on line B-B of FIG. 4.
[0040] The electrolysis apparatus 2 of the present embodiment mainly differs from the first
embodiment in that the evaporation restraining member 60 is replaced by an evaporation
restraining member 80 with other structures being identical to each other. Therefore,
the present embodiment will be described below with a focus on such a differing point
and like or corresponding component parts bear like reference numerals to suitably
simplify the description or to omit such a description.
[0041] As shown in FIGS. 4 to 6, more particularly, the evaporation restraining member 80
is a circular plate-like member placed on the liquid surface of electrolyte 70 in
a floating state so as to cover a nearly greater part of the liquid surface of electrolyte
70. The evaporation restraining member 80 has the same structure as that of the evaporation
restraining member 60 of the first embodiment and includes a pair of first through-bores
80a inserting the electrode bars 37 of the electrode section 30, and a plurality of
second through-bores 80b but differs from the evaporation restraining member 60 of
the first embodiment in respect of a detailed structure of the second through-bores
80b. Also, the pair of first through-bores 80a of the evaporation restraining member
80 has the same structure as the pair of first through-bores 60a of the evaporation
restraining member 60 of the first embodiment.
[0042] That is, the plurality of second through-bores 80b is provided in a limited way in
an inward area surrounded with a circle 85, having a diameter composed of a distance
between respective center axes of the pair of first through-bores 80a and 80a (i.e.
between respective center axes of the pair of electrode bars 37 and 37), which passes
across respective center points of the pair of first through-bores 80a and 80a as
to the x-y plane. In other words, the plurality of second through-bores 80b is provided
in a limited region involving a projection geometry, projected onto the evaporation
restraining member 80, of the electrode unit 30a which is immersed in electrolyte
70.
[0043] Therefore, the evaporation restraining member 80 has a structure having the plurality
of second through-bores 80b provided in the limited way only at the region corresponding
to an upper area of the electrode unit 30a immersed in electrolyte 70. Meanwhile,
a remnant area, in which none of such through-bores 80b is provided in the evaporation
restraining member 80, realizes a structure for reliably covering the liquid surface
of electrolyte 70.
[0044] With the structure of the present embodiment, accordingly, the evaporation restraining
member 80 is capable of minimizing an exposed area of the liquid surface of electrolyte
70 to reliably decrease the amount of evaporated electrolyte 70 while enabling by-product
gas, generated upon electrolysis initiated at the electrode unit 30a, to be directly
exhausted to the space region 40 at high efficiency in an area immediately above the
electrode unit 30a. This reliably prevents by-product gas from accumulating at a lower
area of the evaporation restraining member 80.
[0045] Further, a reduction in the amount of evaporated electrolyte 70 results in a decrease
in a heat radiation effect of electrolyte 70. As a result, electrolyte 70 can have
an increased heat retention effect with resultant improvement in heating efficiency
of the heating section 20.
[0046] With the evaporation restraining member 80 of the present embodiment, the pair of
first through-bores 80a are provided for inserting the pair of electrode bars 37,
respectively, and, in addition thereto, the second through-bores are provided in the
evaporation restraining member 80 to allow the liquid surface of electrolyte 70 to
be exposed in the limited region involving the projection geometry, projected onto
the evaporation restraining member 80, of the electrode unit 30a immersed in electrolyte
70. Thus, the evaporation restraining member 80 may be conceivably applied in various
modified forms as typically described below in detail.
[0047] FIG. 7 shows a positional relationship corresponding to that of FIG. 5 and represents
an enlarged top view of an evaporation restraining member of a modified form of the
present embodiment.
[0048] As shown in FIG. 7, in particular, the evaporation restraining member 80A of the
modified form has a single second through-bore 80Ab having a contour continuous with
that of a pair of first through-bores 80Aa through which the pair of electrode bars
37 are inserted, respectively, with the pair of first through-bores 80Aa and the second
through-bore 80Ab providing a single through-bore in a continuous contour as a whole.
[0049] More particularly, in addition to that the second through-bore 80Ab has an opening
configuration which is formed in a limited region involving a projection geometry,
projected onto the evaporation restraining member 80A, of the electrode unit 30a immersed
in electrolyte 70, the second through-bore 80Ab has an opening configuration which
corresponds to the projection geometry of the electrode unit 30a, i.e. which matches
the projection geometry of the electrode unit 30a.
[0050] With such a structure of the modified form, accordingly, only an upper region corresponding
to the electrode unit 30a immersed in electrolyte 70 is exposed to the space region
40 in a limited way. This allows electrolyte 70 to have the liquid surface exposed
in a limited small surface area with a reliable reduction in the amount of evaporated
electrolyte 70 while enabling by-product gas, resulting from electrolysis initiated
at the electrode unit 30a, to be directly exhausted to the space region 40 with increased
efficiency. This prevents by-product gas in a further reliable manner from accumulating
in an area beneath the evaporation restraining member 80A.
[0051] FIG. 8 shows a positional relationship corresponding to that of FIG. 5 and represents
an enlarged top view of an evaporation restraining member of another modified form
of the present embodiment.
[0052] With an evaporation restraining member 80B of another modified form shown in FIG.
8, in particular, four second through-bores 80Bb are juxtaposed in an area sandwiched
between a pair of first through-bores 80Ba. In addition, the pair of first through-bores
80Ba have the same structures as those of the pair of through-bores 60a of the evaporation
restraining member 60 of the first embodiment.
[0053] More particularly, in addition to that the four second through-bores 80Bb have opening
configurations formed in limited regions involving a projection geometry, projected
onto the evaporation restraining member 80A, of the electrode unit 30a immersed in
electrolyte 70, the four second through-bores 80Bb have opening configurations respectively
corresponding to four gap portions each of which is defined as a gap portion between
an adjacent pair of five electrodes 33 of the electrode unit 30a. That is, the second
through-bores 80Bb have opening configurations matching the projected shapes of the
gap portions of the five electrodes 33, respectively.
[0054] With such a structure of another modified form, accordingly, only an upper region
corresponding to the four gap portions of the five electrodes 33 of the electrode
unit 30a immersed in electrolyte 70 are exposed to the space region 40. This enables
by-product gas, resulting from electrolysis initiated at the electrode unit 30a, to
be directly exhausted to the space region 40 with increased efficiency. This further
reliably prevents by-product gas from accumulating in an area beneath the evaporation
restraining member 80B while permitting the liquid surface of electrolyte 70 to have
a further minimized exposed surface area to reliably decrease the amount of evaporated
electrolyte 70.
(Third Embodiment)
[0055] Next, an electrolysis apparatus of a third embodiment according to the present invention
will be described below in detail with reference to the accompanying drawings.
[0056] FIG. 9 is a cross-sectional view of the electrolysis apparatus of the present embodiment.
FIG. 10 is an enlarged top view of FIG. 9, as viewed in the Z-direction that is parallel
to the z-axis, for representing an evaporation restraining member used in the present
embodiment. FIG. 11 is an enlarged cross-sectional view taken on line C-C of FIG.
10.
[0057] The electrolysis apparatus 3 of the present embodiment mainly differs from the second
embodiment in that the evaporation restraining member 80 of the second embodiment
is replaced by an evaporation restraining member 90 with other structures being identical
to each other. Therefore, the present embodiment will be described below with a focus
on such a differing point and like or corresponding component parts bear like reference
numerals to suitably simplify the description or to omit such a description.
[0058] As shown in FIGS. 9 to 11, more particularly, the plurality of second through-bores
80b of the evaporation restraining member 80 of the second embodiment represent simplified
circular holes whereas a plurality of second through-bores 90b of the evaporation
restraining member 90 include through-holes each formed in a top-sliced cone-shaped
inner circumferential surface 90w. In addition, a pair of first through-bores 90a
of the evaporation restraining member 90 have the same structure as the pair of first
through-bores 60a of the evaporation restraining member 60 of the first embodiment
and the pair of first through-bores 80a of the evaporation restraining member 80 of
the second embodiment.
[0059] That is, the plurality of second through-bores 90b include the through-holes each
having the top-sliced cone-shaped inner circumferential surface 90w with an opening
diameter d6, placed on the evaporation restraining member 90 at a bottom wall thereof
facing electrolyte 90, which is greater than an opening diameter d5 placed on the
evaporation restraining member 90 at a top wall thereof facing the space region 40.
With each of the second through-bores 90b, for instance, the opening diameter d6,
placed at the bottom wall facing electrolyte 90, is 20mm and the opening diameter
d5, placed at the top wall facing the space region 40, is 15mm.
[0060] With such a structure of the present embodiment, accordingly, by-product gas, resulting
from electrolysis, can smoothly escape through the second through-bores 90b to prevent
by-product from accumulating in an area beneath the evaporation restraining member
90, while reliably minimizing an exposed surface area of the liquid surface of electrolyte
70 to enable a reduction in the amount of evaporated electrolyte 70.
[0061] The evaporation restraining member 90 of the present embodiment is intended to provide
a structure in which by-product gas, resulting from electrolysis, is enabled to smoothly
escape through the second through-bores 90b and a variety of modifications are conceivably
provided as typically described below.
[0062] FIG. 12 corresponds to the positional relationship shown in FIG. 11 and is an enlarged
cross-sectional view of an evaporation restraining member of a modified form of the
present embodiment.
[0063] As shown in FIG. 12, more particularly, with an evaporation restraining member 90A
of the present modification, each of a plurality of second through-bores 90Ab has
an inner wall 90w1, formed in a top-sliced cone-shaped circumferential wall with a
diameter increasing downward from a top wall facing the space region 40, and an inner
wall 90w2 formed in a top-sliced cone-shaped circumferential wall with a diameter
decreasing upward from a bottom wall facing electrolyte 70.
[0064] That is, the inner walls 90w1 and 90w2 of each of the plurality of second through-bores
90Ab are formed in a surface structure in which both of adjacent top-sliced cone-shaped
inner walls are connected to each other via a stepped portion formed in a planar wall
portion. When complicated work is needed for performing processing of the inner wall
formed in a continuous top-sliced cone-shaped inner wall, the evaporation restraining
member 90A can be processed at the top and bottom walls in a separate fashion, providing
a further simplified processing capability.
[0065] With the structure of the present embodiment, therefore, simply performing the processing
results in the formation of the second through-bores 90Ab that enables by-product
gas, resulting from electrolysis, to smoothly escape. Such by-product gas can be exhausted
to the space region 40 at further increased efficiency. This reliably prevent by-product
gas from accumulating in an area beneath the evaporation restraining member 90A while
minimizing an exposed surface area of the liquid surface of electrolyte 70, thereby
reliably enabling a reduction in the amount of evaporated electrolyte 70.
[0066] FIG. 13 corresponds to the positional relationship shown in FIG. 11 and represents
an enlarged cross-sectional view of an evaporation restraining member of another modified
form of the present embodiment.
[0067] As shown in FIG. 13, more particularly, with an evaporation restraining member 90B
of the present modification, each of a plurality of second through-bores 90Bb has
an inner wall 90w3 formed with a circumferential surface with a diameter continuously
and decreasing upward in a decrescent way from a bottom wall facing electrolyte 70.
[0068] That is, the inner wall 90w3 of each of the plurality of second through-bores 90Bb
has a structure having a curved surface that smoothly varies from an area facing electrolyte
70 to another area facing the space region 40. This allows by-product gas, resulting
from electrolysis, to smoothly escape upward without unnecessarily disturbing a flow
of by-product gas resulting from electrolysis such that by-product gas can be guided
to the space region 40.
[0069] With the structure of the present embodiment, therefore, by-product gas resulting
from electrolysis can smoothly escape through the second through-bores 90Bb, thereby
enabling by-product gas resulting from electrolysis to be exhausted to the space region
40 at further increased efficiency. This reliably prevent by-product gas from accumulating
in an area beneath the evaporation restraining member 90B while minimizing an exposed
surface area of the liquid surface of electrolyte 70, thereby reliably enabling a
reduction in the amount of evaporated electrolyte 70.
[0070] Further, the inner wall structure of the various second through-bores 90b, 90Ab and
90Bb, formed in the evaporation restraining members 90, 90A and 90B, respectively,
may be applied to parts of such through-bores and remaining through-bores may take
simplified circular holes.
[0071] Furthermore, the inner wall structure of the various second through-bores 90b, 90Ab
and 90Bb, formed in the evaporation restraining members 90, 90A and 90B, respectively,
may be applied to parts of or a whole of the second through-bores 80b of the evaporation
restraining member 80 of the second embodiment, parts of or a whole of the second
through-bores 80Ab of the evaporation restraining member 80A or parts of or a whole
of the second through-bores 80Bb of the evaporation restraining member 80B.
[0072] Hereunder, test examples complying the various embodiments described above will be
described below in detail.
(Example 1)
[0073] First, in an example 1, electrolysis of electrolyte was conducted using the electrolysis
apparatus 1 of the first embodiment under a condition mentioned below.
[0074] The electrolysis cell 10, having an inner diameter d1 of 400mm with a wall thickness
t1 of 20mm, was fixedly placed inside the heating section 20. Thereafter, zinc chloride
was poured as a metal compound into the electrolysis cell 10, in which zinc chloride
was heated up to a temperature of 550°C to be melted to adequately decrease liquid
resistance of poured zinc chloride, thereby forming electrolyte 70.
[0075] Subsequently, the electrode unit 30a, supported with the electrode bars 37 each made
of iron and including the protector tube with a diameter d4 of 50mm, was immersed
in electrolyte 70. Then, the electrode bars 37 were inserted through the first through-bores
60a of the evaporation restraining member 60, made of graphite and having an outer
diameter d5 of 390mm with a wall thickness t2 of 5mm, which had the first through-bores
60a each with an opening diameter d2 of 60mm and the second through-bores 60b each
with an opening diameter d3 of 20mm. The evaporation restraining member 60 was dropped
onto the liquid surface of electrolyte 70, on which the evaporation restraining member
60 is placed in a floating condition.
[0076] The lid body 45, having the exhaust section 50 connected to the exhaust system, has
the open end whose inner wall 45a is unitarily fixed to the outer wall 10b of the
open end of the electrolysis cell 10 via the seal member, thereby defining the space
region 40.
[0077] By using the electrolysis apparatus 1 of the structure set forth above, the electrode
unit 30a is supplied with electric current with current density of 0.5Acm2, thereby
conducting electrolysis of electrolyte 70 continuously for 8 hours.
[0078] During such electrolysis, an inside of the lid body 45 through an observation window
(not shown) located on the lid body 45 was observed, thereby confirming the presence
of or absence of the occurrence of electrolyte mist under a visual observation method.
Further, after electrolysis has been completed, a comparison was made between weights
of the filter 57 made of carbon felt on stages before and after electrolysis to check
the amount of evaporated electrolyte 70, i.e. the amount of generated electrolyte
mist, upon which evaluation was made in terms of a resulting increment.
(Example 2)
[0079] Next, in an example 2, electrolysis of electrolyte was conducted using the electrolysis
apparatus 2 of the second embodiment under the same condition as that of the example
1. During electrolysis, the presence of or absence of the occurrence of electrolyte
mist was similarly confirmed under the visual observation method. In addition, after
electrolysis, a comparison was similarly made between weights of the filter 57 on
stages before and after electrolysis. Also, the structures of various modifications
of the second embodiment were not adopted.
(Example 3)
[0080] Subsequently, in an example 3, electrolysis of electrolyte was conducted using the
electrolysis apparatus 3 of the third embodiment under the same condition as that
of the example 1. During electrolysis, the presence of or absence of the occurrence
of electrolyte mist was similarly confirmed under the visual observation method. In
addition, each through-bore 90b had an opening diameter d6 of 20mm at the end facing
electrolyte 70 and an opening diameter d5 of 15mm at the other end facing the space
region 40. Moreover, the structures of various modifications of the third embodiment
were not adopted.
(Comparative Example)
[0081] For a comparative example, electrolysis was conducted under the same structure and
the condition as those of the apparatus used in the example 1 except that the evaporation
restraining member 60 is not provided. During electrolysis, the presence of or absence
of the occurrence of electrolyte mist was similarly confirmed under the visual observation
method. After electrolysis, a comparison was similarly made between weights of the
filter 57 made of carbon felt on stages before and after electrolysis.
[0082] With the examples 1 to 3, during electrolysis continuously conducted for 8 hours,
observing the inside of the lid body 45 through the observation window (not shown)
provided on the lid body 45 allowed the inside of the lid body 45 to be viewed well.
[0083] With the comparative example, on the contrary, the lid body 45 was internally filled
with white-colored mist of zinc chloride under a status in which no inside could be
viewed. Such a result enabled an evaluation to be made that with the examples 1 to
3, the amount of electrolyte mist can be further effectively reduced than that obtained
in the comparative example.
[0084] Further, with the examples 1 to 3, the increment in weight of the filter 57 on a
stage after electrolysis continuously conducted for 8 hours decreased to 1/15 of the
increment in weight of the filter 57 in the comparative example. Among the examples
1 to 3 in comparison, the increment in weight of the filter 57 on a stage of electrolysis
in the example 3 marked the smallest value. As a result, the examples 1 to 3 can be
evaluated to have further favorable effects of efficiently minimizing the occurrence
of electrolyte mist than that obtained in the comparative example.
[0085] With the present invention, further, it is of course to be appreciated that a kind,
an arrangement and the number of pieces of component members are not limited to those
of the embodiments set forth above and modifications may be made without departing
from the scope of the invention upon suitably substituting those component elements
by those which provide equivalent operations and effects.
INDUSTRIAL APPLICABILITY
[0086] As set forth above, the present invention provides an electrolysis apparatus, available
to minimize the amount of evaporated electrolyte while preventing the occurrence of
the clogging of an exhaust pipe without causing a reduction in temperature of electrolyte,
which has a general-purpose and universal characteristic based on which the present
invention is expected to be applied to a variety of electrolysis apparatuses.