JPS6254876B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of sodium chlorate, and more particularly to a chlorate production apparatus and a chlorate production apparatus equipped with a large number of electrolytic cells.

Sodium chlorate is a valuable industrial agent,
Manufactured by electrolysis of an aqueous sodium chloride solution. Various electrolytic cells are known for carrying out electrolysis.

The present invention provides a method and apparatus for producing sodium chlorate which is particularly improved compared to conventional methods.

According to the present invention, there is provided a sodium chlorate production apparatus having a plurality of electrolyzers connected in parallel to each other and equipped with a single acidification apparatus, a brine production apparatus, and a heat exchanger.

Each electrolyzer has a plurality of chlorate production electrolyzers connected in parallel to each other and a common reaction tank from which brine for electrolysis is supplied and from which the electrolyzed brine is removed. The temperature of the reaction tank liquid, ie, the electrolyzed brine, is controlled by adjusting the flow rate of the liquid sent to the reaction tank.

The chlorate production electrolyzer has a box-like structure welded on three sides, a manifold with entrances and exits at the top and bottom is welded, and the fourth side is insulated and bolted to the rest of the box-like structure. There is. Vertical thin anode plates and cathode plates are inserted alternately at intervals to form a plurality of vertical grooves through which the electrolytic solution flows, extending between an inlet and an outlet through which the electrolytic salt water flows. . The electrode plates are inserted and welded into vertical slots formed on each support plate.

A plurality of non-conductive spacer members are used in the electrolytic cell to maintain the alternately inserted thin anode and cathode plates electrically insulated and spaced apart; This spacer member is one of the features of the present invention.

Referring to FIG. 1, FIG. 1 shows a sodium chlorate manufacturing apparatus 10 including a number of electrolytic cells. The chlorate production apparatus 10 consists of a plurality of chlorate production electrolyzers 12 connected in parallel. Although two chlorate production electrolyzers 12 are shown, more will typically be used depending on the desired output. Each electrolyzer 12 is sized to produce, for example, approximately 1200 tons/year of sodium chlorate.

Each chlorate production electrolyzer 12 has a reaction tank containing brine, in which a reaction for producing chlorate from the electrolysis product takes place. A plurality of electrolytic cells 16 without a diaphragm are arranged in parallel with each other in the tank 14.
The electrolytic solution is sent from the tank 14 to each electrolytic cell 16, and the electrolyzed solution from each electrolytic cell 16 is circulated to the tank 14. Each reaction tank 14 has an inlet pipe 18 for supplying electrolytic brine and an outlet pipe 20 for removing sodium chlorate solution. The reaction tank 14 further has an exhaust port 22 for removing the gaseous products of electrolysis.

The flow rate of brine supplied to each reaction tank 14 is individually adjusted by manual valve 23 depending on the desired temperature of the reactor liquid. The outlet pipe 20 of the sodium chlorate solution may be provided with a measuring device 25 for measuring the temperature of the solution, thereby making it possible to modify the flow rate of the liquid fed to the reactor 14.

Line 20 of sodium chlorate solution is line 2
1 to form a single product solution;
A single common mixing tank 24 is fed. Sodium chlorate solution is removed from tank 24 by line 26 as a product of manufacturing apparatus 10.
A sodium chloride solution is supplied by line 28 to a mixing tank 24, and the solution is converted to the required amount for electrolysis.
Hydrochloric acid necessary to acidify to a pH, eg, about 6.8, is supplied to the mixing tank by line 30.
A sodium dichromate catalyst for the electrolytic reaction may be included in the sodium chloride solution in feed line 28.

A vent line 31 may be provided in the mixing tank 24 to remove residual gas that enters the mixing tank with the sodium chlorate solution in line 21.

The interior of the mixing tank 24 is divided into two parts by a buckle 32 extending upward from the bottom. The sodium chlorate solution in line 21 is discharged into one chamber below the liquid level to which the product withdrawal line 26 is connected, and the sodium chloride solution and hydrochloric acid supply lines 28 and 30 are discharged into the other chamber below the liquid level. released. In this way the product chlorate stream 26 is avoided from being contaminated by the feedstock;
On the other hand, mixing of the chlorate solution overflowing the bucket 32 with the feedstock is possible.

A sodium chlorate solution rich in sodium chloride and acidified with hydrochloric acid (hereinafter referred to as "brine") is removed from the second chamber of the mixing tank 24 by line 34 and passed through a heat exchanger 36 of suitable construction. Ru.
The brine is then fed in parallel to the plurality of electrolyzers 12 by respective feed lines 18.

Heat exchanger 36 cools the circulating liquid in line 34 to the desired feed temperature, eg, about 40° C., and the heat generated in electrolyzer 16 is removed as sensible heat in the overflow product of line 20. As mentioned above, the temperature of this liquid is adjusted to a desired value, for example in the range of about 60 DEG C. to about 90 DEG C., by adjusting the supply rate of salt water to the electrolyzer 12 with a valve.

The electrolytic cells 16 are electrically connected to each other by flexible electrical connectors 38 so that the electrolytic cells 16 can be moved and placed in any desired location.

Each electrolytic cell 16 is provided with a valved drain line 40 and individual flow control valves 42 to cut off flow to and drain the individual or all electrolytic cells.

Therefore, the sodium chlorate production device 10 includes a single brine production device, an acidification device, a heat exchanger, and a large number of sodium chlorate production electrolytic cells 12 that work in parallel with each other, and the number of electrolytic cells 12 is individually It is determined according to the processing capacity of the manufacturing apparatus 10 and the production amount of the manufacturing apparatus 10 as a whole. The mixing tank 24 and the heat exchanger 36 are sized to match the production volume of the manufacturing apparatus 10 as a whole.

Electrolyzer 12 and its construction as shown in FIG. 1 has considerable advantages. That is, each electrolyzer 12 has a plurality of electrolyzers 1 operated in parallel.
6 produces a product stream of the desired chlorate concentration. The product streams in each line 20 do not require further electrolysis before being removed from the system. Since each electrolyzer 12 is independent, individual operational problems can be isolated and resolved without interfering with the operation of other electrolyzers 12.

By providing the sodium chlorate production system 10 with a single brine production unit, acidifier, and heat exchanger, the equipment capital associated with these matters can be reduced and the overall operation of the production system 10 can be reduced. Unity of conditions can be easily achieved.

By providing a single reaction tank 14 with a plurality of electrolyzers in parallel in each electrolyzer 12, the influence of individual factors in the operating characteristics of the electrolyzers on product quality can be reduced; Equipment costs are lower than if each electrolyzer 16 had its own reaction tank 14.

The flexibility of the electrical connectors provided between the individual cells 16 allows the relative positions of the cells 16 to vary considerably with respect to each other, reducing the problems that would arise if the cells were fixedly connected. has been resolved.

2-6, details of a preferred construction of the chlorate production electrolyzer 16 of FIG. 1 are shown. The electrolytic cell 16 has a generally closed box structure with a liquid inlet manifold 50 at the bottom and a liquid outlet manifold 52 at the top as shown in FIG. The cathodically protected liquid inlet and outlet manifolds 50 and 52 are joined together by welding to a vertical square cathode end plate 54. The inlet and outlet manifolds 50 and 52 and the cathode end plate are made from mild steel. Projecting straight from the end plate 54 are a plurality of thin, staple cathode plates 56 arranged generally vertically.

Inlet and outlet manifolds 50 and 52 close off the top and bottom of the cell, and a cathode end plate 54 and two outermost cathode plates 56 surround the box cell on three sides. The fourth side of the box electrolyzer is occupied by the anode end plate as shown below.

The use of mild steel inlet and outlet manifolds allows for easy connection to the rest of the box cell by using welding means instead of bolts or other fastening means. however,
Other joining means are required if a corrosion resistant polymeric material is used as the manifold material.

Similarly, the use of electrodes to surround the sides of the cell facilitates construction of the cell, eliminating the need for vaulting and sealing gaskets.

Cathode end plate 54 consists of an inner stay sheet 58 joined to an outer copper or aluminum sheet 60. This two-component structure is an electrolytic cell 16
This facilitates electrical connection to the electrolyzer and reduces voltage drops associated with internal electrolyzer connectors.

The stay sheet 58 has a plurality of vertical slot-like grooves 62, each of which tightly receives the inner edge of the thin cathode plate 56, to which the cathode plate 56 is welded.

The two outermost cathode plates 56 forming the sides of the cell 16 are welded to a peripheral frame member 64 to which the inlet and outlet manifolds 50 and 52 are also welded. The outer protection and reinforcement plate 65 is also the outermost plate 5
It is welded to the outer frame member 64 of 6.

A vertical square anode end plate 66 is provided parallel to the cathode end plate 54 and forms the fourth side of the electrolytic cell 16. The anode end plate 66 has a plurality of vertically aligned thin anode plates 68 extending parallel to and alternating with the cathode plates 56 . The anode end plate 66 consists of an inner titanium sheet 70 bonded to an outer copper or aluminum sheet 72 to facilitate electrical connection with the anode plate and reduce voltage drops associated with internal cell connections. Titanium sheet 70 has a plurality of vertical slot-like grooves 74, each of which tightly receives the inner edge of a thin anode plate 68, to which anode plate 68 is welded. The thin anode plate 68 is preferably made of titanium with an electrically conductive surface, such as a platinum group metal or an alloy thereof or other electrically conductive coating, such as a platinum group metal oxide.

In a box electrolyzer, thin anode plates 68 are arranged alternately with thin cathode plates 56 to form a plurality of vertically flowing parallel channels therebetween, such that the electrolyzer is connected to the inlet manifold 50.
Flows upwardly through electrolytic cell 16 between the electrode plates from to outflow manifold 52 . A spacer member 76 is provided to maintain the desired spacing of electrode plates 56 and 68 from each other.

As shown in Figures 2-6, the alternating electrodes occupy all the space between the side walls of the electrolytic cell, dividing the space into vertically flowing channels 75, so that the electrolytic capacity of the electrolytic cell is very low. expensive.

By providing vertical slots or grooves on the anode and cathode end plates to receive the electrode plates, welding and assembling the electrode plates with their respective support plates therein, and utilizing spacer members 76, the electrolytic cell is assembled. To maximize internal space, the electrode plates are made very thin, e.g., about 1/16 to about 1/8 inch (about 0.16 to about 0.32 cm) thick.

This structure is significantly different from the conventional case,
Conventionally, the anode plates are joined to the end plates by bolts, which limits the number of anode plates that can be installed, and generally limits the desired gap between the electrodes to about 1/16 to about 1/8 inch. ~about 0.32
cm), the cathode plate is thick, usually about 1/
It is made into 2 inches (about 1.27 cm).

Another advantage of the welded anode plate construction is that voltage drops between the bolted anode plate and the support plate as in the conventional case are avoided.

By using a thin cathode plate in the electrolytic cell 16, a much smaller and lighter electrolytic cell can be made for the same capacity, and since the cathode is generally flexible, it is easier to use a bolted anode. Assembly of the anode and cathode plates is easier compared to using thicker, less flexible cathode plates in construction.

As can be seen in Figure 3, the spacer member 76 utilized to maintain the electrode plates in the desired relative position is constructed from a substantially rigid, non-conductive, corrosion resistant material such as polytetrafluoroethylene. It consists of an integral member 78. The member 78 has a short cylindrical portion or shank 80 slightly larger than the thickness of the electrode plate 56 or 68 and two head portions 82 located at opposite ends of the cylindrical portion 80 and having a larger diameter than the cylindrical portions.

Each head portion 82 has an inner surface 81 , an outer plane 83 parallel to said inner surface 81 , an angled rim 85 and a cylindrical portion 87 extending between said inner surface 81 and said rim 85 .

Said inner surface 81 is formed by electrode plate 56 or 68 when spacer member 76 is assembled as described below.
The outer surface 83 is adapted to contact the adjacent electrode plate to maintain the desired spacing. The axial thickness of head portion 82 is the value necessary to maintain the desired electrode spacing.

Each of the circular head portions 82 is such that the center of curvature is located at the axis of the short cylindrical portion or shank 80, creating a symmetrical structure.

The shank 80 preferably has a cylindrical shape for ease of manufacture and handling, but may have other cross-sectional shapes such as square or hexagonal.

Similarly, the head portion 82 preferably has a circular cross-sectional shape, but if the maximum lateral dimension is larger than the maximum dimension of the cross-section of the shank portion 80, the cross-sectional shape may be quadrilateral, oval, hexagonal, or right-angled. You can change the shape.

Spacer member 76 is fabricated from a substantially rigid, non-conductive, corrosion resistant material according to conventional procedures such as machining, molding, etc.

Spacer portions 76 are installed in as many numbers as necessary to provide adequate spacing at the end of electrode plate 56 or 68 opposite end plate 54 or 66. i.e. a slot 84 extending inwardly from the end of the electrode plate, preferably at right angles.
and the width of the slot 84 is equal to the width of the cylindrical portion 80.
spacer member 7.
6 into the slot 84 and the head portion 82
The spacer member 76 is placed in contact with the outer surface of the electrode plate by bending the tongue 86 formed between the slot 84 and the generally parallel short slot 88 downwardly and inwardly. The spacer member 76 is inserted into the slot 84 in a manner that prevents it from slipping out of the slot 84.
installed inside.

Each electrode plate is provided with a plurality of such spacer members 76, the number depending on the size of the electrode plate. Typically, at least three spacer members 76 are provided, one at each end of the electrode plate and one in the middle.

Spacer members have also been used in conventional electrolyzers, but they consist of two parts that are pressed or otherwise joined to holes in the electrolyzer plates. These two part spacers were unsatisfactory as they tended to separate and become ineffective during cell assembly.

The use of an integral spacer member 76 eliminates the conventional problem and maintains good spacing between the electrodes for long periods of time.

An insulating sealing gasket 90 is provided around the anode end plate 66 to electrically isolate the anode end plate from the adjacent cathode frame member 64 in the cell. Anode plate 66 is attached to frame member 64 by suitably insulated bolts 92 and nuts projecting through holes 94 in the adjacent member. The nut and bolt combination 92 is fitted with a sleeve 93 having sufficient strength to withstand the tightening pressure necessary to form a tight leak-tight seal around the gasket 90.
and Washer 95 are used. These suitable materials are melamine for the washer 95 and polypropylene for the sleeve 93.

Electrical lead connection plate 96 is welded to the outer surface of cathode end plate 54 , and similarly electrical lead connection plate 98 is welded to the outer surface of anode end plate 66 . Connection plates 96 and 98 are connected to appropriate power leads, not shown.

Cell support plates 100 extending horizontally from the side walls of the cell allow the cell to be maintained in a vertical position in a suitable frame.

FIG. 7 shows a pipe connecting portion for connecting the electrolytic cell 16 to the tank 14. Pipe members 102 made of a corrosion-resistant, electrically conductive material such as titanium are provided in short sections electrically isolated from each other by suitable insulation assemblies 104;
Corrosion of the pipe resulting from potential differences between the pipe and the liquid flowing through it as well as current leakage along the pipe are minimized.

The diameters of the inlet and outlet pipes 102 are generally much smaller than the diameters of pipes used in other upward flow type electrolyzer systems, resulting in lower fluid flow rates across the electrode surface. 35000
For Ampere electrolyzers, typical diameter values are approximately 4 inches (approximately 10 cm) versus conventional values of approximately 8 to 10 inches (approximately 20 to 25 cm), and flow rates are approximately 40 cm/sec. In contrast, it is approximately 10 cm/sec.

It has been found that the oxygen generation and inefficiency of this relatively low liquid flow rate is negligible, and gas generation is determined by flow conditions rather than retention volume. This use of much smaller diameter pipes saves equipment costs and reduces current leakage.

In summary, the present invention provides a sodium chlorate production apparatus with certain advantages using a unique electrolytic cell and a unique spacer member, and various application variations are possible within the scope of the present invention. You should understand that.

The gist of the invention is as follows.

(a) In a method for producing sodium chlorate by electrolyzing a sodium chloride solution, the sodium chloride solution to be electrolyzed is supplied in parallel from a single raw material source to a plurality of sodium chlorate production zones, and sodium chlorate production zones are withdrawn in parallel to form a single sodium chlorate stream, each of said sodium chlorate production zones being supplied with a sodium chloride solution from which the sodium chlorate solution is extracted. a plurality of diaphragm-free electrolytic zones each connected to a single reaction zone to be withdrawn; form a sodium chloride solution source, adjust the PH of the resulting mixed solution to the value required for electrolysis, and apply the PH adjusted mixed solution to a heat exchanger to form a single raw material supply having the desired temperature. A method for producing sodium chlorate comprising the step of recovering the remainder of said single sodium chlorate stream as a product stream.

(b) measuring the temperature of the sodium chlorate solution exiting each of said sodium chlorate production zones;
Said (a) characterized in that the flow rate of sodium chloride supplied to each of said sodium chlorate production zones is individually adjusted as necessary, and the measured temperature of the solution is preferably maintained at about 60 to about 90°C. )
The method described in section.

(c) each electrolytic zone has a plurality of parallel vertical liquid flow passageways across which an electric current flows, each passageway extending from a lower inlet to an upper inlet of the electrolytic zone; The method according to any one of paragraphs (a) and (b) above, characterized in that:

(d) said electrolysis zones are electrically connected in series but otherwise physically separate from each other;
The method described in paragraph (a), (b) or (c).

(e) In an apparatus for producing a sodium chlorate solution by electrolysis of a sodium chloride solution according to the method of paragraph (a) above, each of the plurality of electrolyzers 12 has a plurality of individual electrolytic cells 16. However, the individual electrolytic cells 16 are not physically connected to each other other than being connected electrically in series to each other by flexible electrical connectors 38, but are fluidly connected to a single reaction tank 14. Each electrolytic cell 16 is connected from a lower inlet 50 to an upper inlet 5.
a plurality of anodes 68 and cathodes 5 alternately arranged to form an electrolytic channel 75 extending to 2;
6, the raw material supply conduit 18 is connected in parallel to each reaction tank 14 of the plurality of electrolyzers 12, and the product conduit 20, 21
are connected in parallel to the reaction tanks 14 of each of the plurality of electrolyzers 12, and the mixing tank 24 is connected to the product conduit 21, the sodium chloride solution introduction pipe 28, and the hydrochloric acid introduction pipe 30. , the mixing tank 24 is further connected to the raw material supply pipe 18 via a circulation outlet pipe 34 and a heat exchanger 36, and is also connected to a product outlet pipe 26 for removing the sodium chlorate product from the mixing tank 24. A device characterized by:

(f) Each product conduit 20 has a temperature measuring device 25, and each raw material supply pipe 18 has a temperature measuring device 25 for adjusting the amount of liquid supplied to the reaction tank 14 according to the measured temperature of the liquid in the conduit 20. The device according to item (e) above, further comprising a flow rate regulating valve 23 for controlling the flow rate.

(g) The mixing tank 24 is provided with an internal buckle 32 extending upright from the bottom to divide the interior into two sections, including a sodium chloride solution inlet pipe 28, a chlorine inlet pipe 30 and a circulation outlet pipe. 34 is connected to one section, and the product conduit 21 and the product outlet tube 26 are connected to the other section.
Equipment described in Section.

(h) In an electrolytic apparatus for producing sodium chlorate by electrolysis of sodium chloride useful in the apparatus of paragraph (e) above, a plurality of individual electrolytic cells 16
are electrically connected to each other in series by flexible electrical connectors 38 and otherwise are not physically connected to each other and are fluidly connected to a single reaction tank 14, with each of said Electrolytic cell 1
6 has a plurality of anodes 68 and cathodes 56 arranged alternately to form an electrolytic channel 75 extending from the lower inlet 50 to the upper inlet 52, and the raw material supply pipe 18 is connected to supply a sodium chloride solution. An electrolyzer, characterized in that it is connected to the reaction tank 18 and that a product conduit 20 is connected to the reaction tank 14 for removing the product sodium chlorate.

(i) The product conduit 20 is provided with a temperature measuring device 25, and the raw material supply pipe 18 is provided with the conduit 2.
(h) above, characterized in that a flow rate adjustment valve 23 is provided for adjusting the amount of liquid supplied to the reaction tank 14 according to the measured temperature of the liquid in the reaction tank 14.
Electrolyzer as described in section.

(j) The reaction tank 14 and each electrolytic cell 16
The electrolysis device according to item (h) or (i) above, characterized in that the conduit extending between the pipe members 102 has a plurality of pipe members 102 that are insulated from each other.

(k) In an electrolytic cell for the electrolysis of sodium chloride for producing sodium chlorate useful in the apparatus of paragraph (e) and the electrolyzer of paragraph (h), the cathode support plate 54 made of mild steel;
4; a titanium anode support plate 66 located parallel to the cathode support plate 54; a plurality of titanium anode support plates 66 that are welded to respective parallel grooves 62 provided in the cathode support plate 54 and protrude from the cathode support plate 54 toward the anode support plate 66; parallel thin mild steel cathode sheets 56; welded to respective parallel grooves 74 provided in the anode support plate 66, protruding from the anode support plate 66 toward the cathode support plate 54; a plurality of parallel thin anode sheets 68 of titanium with conductive surfaces alternating with said cathode sheets 56 to form a channel 75; welded to said cathode support plate 54 and to said cathode support plate 54; A mild steel inlet 50 welded to a frame 64 (the frame 64 includes anode support plates 66, 90, 92,
93, 95, but insulated); and a mild steel outlet 52 welded to said frame 64 and cathode support plate 54.

(l) each of said cathode support plate 54 and anode support plate 66 has a copper or aluminum sheet 60, 72 bonded to the opposite side of said groove 62, 74;
Electrolytic cell described in paragraph (k).

(m) Each of the electrode sheets 56 and 68 is
The electrolytic cell of paragraph (k) or (l) above, wherein the electrolytic channel 75 has a thickness of about 0.16 to about 0.32 cm, and wherein the electrolytic channel 75 has a width of about 0.16 to about 0.32 cm.

(n) (k) above, wherein the adjacent electrode sheets 56, 68 are separated from each other at an appropriate distance by an electrically insulating spacer member 76;
Electrolytic cell described in (l) or (m).

(o) Each of the spacer members 78 has a length slightly greater than the thickness of the electrode sheets 56, 68, and includes an elongated shank portion 80 extending through a slot 84 cut inwardly from one end of the electrode sheet. , and an inner surface 81 integral with each end of the shank portion 80 and in contact with the outer surfaces of the adjacent electrode sheets 56 and 68, and an outer surface 8 parallel to the inner surface.
3, the maximum transverse dimension of each head section 82 being greater than the maximum cross-sectional dimension of the shank 80 and the width of the slot 84; corresponds to the desired spacing between the electrode sheets 56, 68, and the slot 84 has an obstruction 86 to prevent the spacer member 76 from slipping out of the slot 84. The electrolytic cell according to item (n) above.

(p) an integral electrically insulated electrode spacer member for use in separating electrode sheets from one another in an electrolytic cell, having an elongated shank portion 80 and an integral head portion 82 at each end thereof, said shank having an integral head portion 82; The portion 80 is the electrode sheet 5
6,68 extending from one end of said electrode sheet 56,68 through an inner cut slot 84;
The slot 84 has an obstacle 86 for preventing the spacer member 76 from slipping out after the spacer member 76 is inserted, and each head portion 82 is connected to the adjacent electrode sheet 5.
6 and 68, and an outer surface 83 parallel thereto, the maximum transverse dimension of each head portion 82 being the maximum cross-sectional dimension of the shank 80; A spacer element greater than the width of said slot 84, wherein the maximum axial thickness of said head portion 82 corresponds to the desired spacing between said electrode sheets.

(q) said shank portion 80 is cylindrical, having a diameter slightly smaller than the width of said slot 84, and each head portion 82 is circular, with the center of curvature of said shank portion 80; Spacer element according to clause (p), characterized in that it has an axially inclined edge 85, preferably around the outer surface 83.

(r) characterized in that said obstruction is formed between said slot 84 and an adjacent short slot 86 parallel thereto, and is formed by a tongue 85 bent inwardly of said slot 84; The spacer member described in item p) or (q).

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a sodium chlorate production apparatus equipped with a large number of electrolytic cells. FIG. 2 is an exploded perspective view of an electrolytic cell used as an embodiment of the present invention. 3 is an enlarged perspective view of an electrode plate spacer member used in the electrolytic cell of FIG. 2. FIG. Fourth
The figure is a cross-sectional view of the electrolytic cell of FIG. 2 taken along line 4--4. FIG. 5 is a cross-sectional view taken along line 5--5 in FIG. 4. FIG. 6 is a cross-sectional view taken along line 6--6 in FIG. 5. FIG. 7 shows the pipes connecting the electrolytic cell to the reaction tank. 12... Chlorate production electrolyzer; 14... Reaction tank; 16... Electrolytic cell; 18... Inlet pipe;
20... Outlet pipe; 22... Exhaust port; 24...
Mixing tank; 36... Heat exchanger; 50... Inlet manifold; 52... Outlet manifold; 54... Cathode end plate; 56... Cathode plate; 66...
...Anode end plate; 68...Anode plate; 7
6...Spacer; 80...Shank part; 82
... Head part; 84 ... Slot; 86 ... Obstacle.

Claims (1)

[Claims] 1. A method for producing sodium chlorate by electrolyzing a sodium chloride solution, in which the sodium chloride solution to be electrolyzed is supplied in parallel from a single raw material source to a complex number of sodium chlorate production zones. , withdrawing sodium chlorate from said plurality of sodium chlorate production zones in parallel to form a single sodium chlorate stream, each of said sodium chlorate production zones being supplied with a sodium chloride solution from which chlorine is extracted; a plurality of membrane-free electrolytic zones each connected to a single reaction zone from which a sodium chloride solution is removed, by adding fresh sodium chloride solution to a portion of said single sodium chlorate stream; to form the single source of sodium chloride solution and the pH of the resulting mixed solution.
is adjusted to the value required for electrolysis, the PH adjusted mixed solution is passed through a heat exchanger to provide a single feedstock source with the desired temperature, and the remainder of the single sodium chlorate stream is used as the product. A method for producing sodium chlorate including a step of recovering it as a stream. 2. An integral electrically insulated electrode spacer member for use in separating electrode sheets from one another in an electrolytic cell, having an elongated shank portion 80 and an integral head portion 82 at each end thereof, said shank portion 80 has a length slightly greater than the thickness of the electrode sheets 56, 68 and extends through a slot 84 cut inwardly from one end of the electrode sheets 56, 68;
is an obstacle 86 for preventing the spacer member 76 from coming off after the spacer member 76 is inserted.
Each head portion 82 has an inner surface 81 in contact with the outer surface of the adjacent electrode sheet 56, 68 and an outer surface 83 parallel thereto.
the maximum transverse dimension of each head portion 82 is greater than the maximum cross-sectional dimension of the shank 80 and the width of the slot 84; A spacer member characterized in that its thickness corresponds to the desired spacing between the electrode sheets.