JPH11286796A - Fluidized-bed electrolytic cell, method for recovering and removing metal such as nickel and treatment of water using the cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluidized-bed electrolytic cell excellent in treating efficiency, a water treating method using the cell and especially a method for efficiently recovering and removing low-concn. metals in a waste water and low-concn. nickel in the waste water. SOLUTION: A main electrode 11 consists of the inner side face of a box- shaped electrolytic cell, an auxiliary electrode 13 consists of a plate of net- shaped electrode covered with a diaphragm, the auxiliary electrode 13 is arranged opposedly to the main electrode 11 in the box-shaped electrolytic cell, and conductive grains are packed in the cell in contact with the main electrode 11. The bottom face of the cell is formed by a substrate substantially permeable to the water to be treated and impermeable to the conductive grains, the water to be treated is introduced from the lower part to fluidize the grains, and a DC voltage is applied between the main electrode 11 and auxiliary electrode 13. In this fluidized-bed electrolytic cell 10 system, one or more electrolytic cells 10 are arranged in parallel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to Au, Ag, P
A fluidized bed used for various electrochemical reactions such as recovery and purification of various metals such as t, Pd, Cu, Pb, Cr, and Cd, electroplating of granules, and decomposition of organic compounds and / or cyanides, etc. The present invention relates to an electrolytic cell, and more particularly to a method for collecting and removing metal ions such as Ni and Sn contained in wastewater using the electrolytic cell.

[0002]

2. Description of the Related Art At present, various kinds of water are used in our daily lives. For example, well water, tap water, industrial water, pure water, ultrapure water, bathtub water, pool water, etc.
The used water is industrial wastewater or domestic wastewater. Alternatively, water containing various substances is used in various industries. Various impurities are contained in factory wastewater and the like, and impurities are removed or useful substances are collected to prevent environmental pollution. In particular, wastewater is treated and reused for effective use of precious water resources.

For example, in a plating step, a cleaning wastewater containing metal ions comes out in order to wash and remove a plating solution attached to a product after plating. Although the contained metal ions are generally low in concentration, the amount of wastewater is large, and there is a problem that the treatment requires a large load on the ion exchange resin. For example, nickel plating is used to decorate aluminum, and nickel or tin is added to this washing wastewater.
-100 ppm, and the load of the ion exchange resin used for the treatment was large.

[0004]

SUMMARY OF THE INVENTION The present invention relates to an electrolytic cell capable of recovering and removing trace amounts of metals contained in wastewater and the like, purifying metals, plating particles, and decomposing organic compounds or cyanide compounds. It is intended to provide a used water treatment method.

It is another object of the present invention to provide a method for efficiently recovering metals such as nickel contained in wastewater.

[0006]

The object of the present invention is achieved by any of the following technical means (1) to (10).

(1) The main electrode is composed of a box-shaped electrolytic cell, and the auxiliary electrode is composed of a plate or mesh electrode covered with a diaphragm. The auxiliary electrode is provided in the box-shaped electrolytic cell as the main electrode. Oppositely disposed, the box-shaped electrolytic cell is filled with conductive particles in a state capable of contacting the main electrode, and the bottom surface of the box-shaped electrolytic tank can substantially pass water to be treated, but the conductive particles are A fluidized-bed electrolytic cell comprising a support that cannot pass through, supplying treated water from the lower part to bring the conductive particles into a fluidized state, and applying a DC voltage between the main electrode and the auxiliary electrode. Are arranged in parallel in one or more fluidized bed electrolytic cells.

(2) The main electrode comprises the inner side surface of the box-shaped electrolytic cell, and the auxiliary electrode comprises at least two perforated plate electrodes or mesh electrodes covered with a diaphragm. It has a formed gap, is arranged so that gas generated on the auxiliary electrode can pass through this gap, the auxiliary electrode is disposed facing the inside of the box-shaped electrolytic cell which is the main electrode, the box-shaped In a state in which the conductive particles can be brought into contact with the main electrode in the electrolytic cell, the bottom surface of the box-shaped electrolytic cell can substantially pass through the water to be treated, but is made of a support that cannot pass through the conductive particles, A fluidized bed electrolytic cell for supplying treated water from the lower part to bring the conductive particles into a fluidized state and applying a DC voltage between the main electrode and the auxiliary electrode, wherein one or more electrolytic cells are arranged in parallel. A fluidized bed electrolytic cell characterized by the above-mentioned.

(3) In the fluidized bed electrolyzer according to the above item (1) or (2), the electrolyzer is configured such that the FBE value obtained by the following equation (1) is 0.2 or more. A fluidized-bed electrolytic cell characterized in that:

FBE = 2 (D + W) / (DW−PQ) (1) P: thickness of auxiliary electrode portion including internal space (cm) Q: width of auxiliary electrode (cm) W: box-shaped main Length of the short side of the electrode chamber (cm) D: Length of the long side of the box-shaped main electrode chamber (cm) (4) The fluidized bed electrolytic cell according to any one of (1) to (3) A method for recovering or removing metal from wastewater using the method, wherein the current density of the side surface of the box-shaped electrolytic cell that is the main electrode serving as the cathode is 1.5 A / dm ² or more; A method for recovering and removing metal using a fluidized-bed electrolytic cell, wherein the fluidized-bed is operated at a current concentration of 3 A / L or more in contact with the main electrode.

(5) A water treatment method for recovering or removing a metal using the fluidized bed electrolytic cell according to any one of (1) to (3), wherein the metal concentration is 500 ppm or less. A water treatment method using a fluidized-bed electrolytic cell, wherein wastewater having an electric conductivity of 100 mS / m or less is treated.

(6) A method for treating the water to be treated containing metal ions in a fluidized-bed electrolytic cell to recover or remove the contained metal component. A method for recovering and removing metals using a fluidized bed electrolytic cell, wherein a part or all of the liquid before or after passing through the fluidized bed electrolytic cell is treated with an anion exchange resin.

(7) The nickel content is 500 ppm
A method for recovering or removing nickel contained in wastewater at a concentration of 10 ppm or less in a fluidized-bed electrolytic cell so as to have a concentration of 10 ppm or less, wherein the pH of a treatment solution in the electrolytic cell is maintained at 6 to 10. To remove and remove nickel.

(8) The nickel concentration is 500 ppm
A method for recovering or removing nickel contained in wastewater at a concentration of 5 ppm or less in a fluidized bed electrolytic cell so as to have a concentration of 5 ppm or less, wherein the pH of the treatment liquid is maintained at 7.7 to 9.2. To remove and remove nickel.

(9) Using a fluidized bed electrolytic cell, the nickel content is 100 ppm or less, and the electric conductivity is 100 mS.
/ M or less in wastewater using a fluidized bed, wherein the treatment is performed while maintaining the pH of the treatment solution at 7.7 to 9.2. Nickel recovery method.

(10) The main electrode is formed of a cylindrical or box-shaped electrolytic cell having an inner side surface, and an auxiliary electrode covered with a diaphragm is disposed facing the main electrode so that the main electrode can contact the main electrode.
It is filled with conductive particles, and the bottom surface of the electrolytic cell is made of a support that can substantially pass through the water to be treated but cannot pass through the conductive particles. A fluidized bed electrolytic cell in which particles are in a fluidized state and a DC voltage is applied between the main electrode and the auxiliary electrode, wherein the water to be treated and the electrolytic gas can pass above the particles in a fluidized state, but the particles cannot. A fluidized-bed electrolytic cell provided with a barrier plate.

[0017]

Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto.
In the following description, although there are definite expressions for terms and the like, they show preferred examples of the present invention, and do not limit the meaning of the terms of the present invention and the technical scope.

An object of the present invention is to provide an electrolytic cell capable of recovering and removing a trace amount of metal contained in waste water, purifying metal, plating on granules, and decomposing organic compounds or cyanide compounds. In particular, an object of the present invention is to provide a fluidized bed electrolytic cell for recovering and removing a trace amount of metal contained in wastewater and a water treatment method using the same.

As shown in the horizontal sectional view of FIG. 1, the side sectional view of FIG. 2, the front sectional view of FIG. 3, and the perspective view of FIG. The electrode surface 11A which is the inner side surface portion of the electrolytic cell, the auxiliary electrode 13 is a flat plate or a mesh electrode, and preferably has a box shape having a gap serving as a gas discharge path 19 between two electrodes, The auxiliary electrode 13 is disposed inside the box-shaped electrolytic cell so that the distance between the main electrode 11 and the auxiliary electrode 13 is substantially constant.

The auxiliary electrode is defined by a diaphragm 15,
The box-shaped electrolytic cell is filled with the conductive particles 14 </ b> A so as to be able to contact the main electrode 11.

For example, in the case of collecting and removing metal, the main electrode 1
1, the box-shaped electrolytic cell side is a cathode, the conductive particles are also a cathode, and the auxiliary electrode 13 is an anode. The liquid to be treated, which is sent from below by a pump or the like, rises through the gap while flowing the conductive particles 14A, and at this time, metal components are electrolytically deposited on the conductive particles and the main electrode. The treated liquid is discharged from the upper part. The treatment of the water to be treated is basically carried out by circulation, but it is also possible to treat the water in one pass by adjusting the supplied current.

FIGS. 1, 2, 3 and 4 show an example of the electrolytic cell of the present invention. The box-type electrolytic cell is preferably made of metal, and the inner side surface acts as a main electrode. The part surrounded by the electrolytic cell is the main electrode chamber. Height of box-shaped electrolytic cell H (c
m), the length W (cm) of the short side inside the box-shaped electrolytic cell, and the length D (cm) of the long side inside the box-shaped electrolytic cell. An auxiliary electrode 13 is disposed inside the box-shaped electrolytic cell, and preferably has a gas discharge path 19 through which the electrolytic gas generated by the auxiliary electrode 13 can be discharged. ) Indicates the thickness of one auxiliary electrode plate or the thickness of the auxiliary electrode including the gap formed by two plates.

When the auxiliary electrode 13 is composed of two plates and a space is provided inside, the electrolytic gas generated on the auxiliary electrode is discharged to the upper portion to prevent the masking of the electrode by the electrode gas and to improve the efficiency. Electrolytic treatment can be performed. Therefore, the auxiliary electrode 13 may be a perforated plate shape, but a mesh shape is preferably used.

The auxiliary electrode 13 is arranged in a state covered by the diaphragm 15. The gap between the auxiliary electrode 13 and the box-shaped electrolytic cell serving as the main electrode 11 is filled with conductive particles 14 </ b> A and used as a fluidized bed 14. The fluidized bed 14 is supplied with a potential from the main electrode side. The lower part of the box-shaped electrolytic cell is constituted by a mesh-like support plate 17 through which the processing liquid can pass and the filled particles cannot pass.

In the present invention, it has been confirmed that the electrolytic cell of this embodiment is particularly preferable as the fluidized bed electrolytic cell 10 when the FBE value calculated from the equation (1) is 0.2 or more.

FBE = 2 (D + W) / (DW−PQ) Equation (1) P: thickness of auxiliary electrode including internal space (cm) Q: width of auxiliary electrode (cm) W: box-shaped main electrode Length of the short side of the chamber (cm) D: Length of the long side of the box-shaped main electrode chamber (cm) The value of FBE is the volume of the main electrolysis chamber which becomes the fluidized bed 14 in the electrolysis cell of the present invention, the main electrode. 11 and the cross-sectional area of water, the distance between the main electrode 11 and the auxiliary electrode 13, the cross-sectional area of the gas discharge part, etc., and the area of the main electrode 11 per volume of the main electrolytic chamber is important. is there. By multiplying the numerator of the above formula (1) indicating the value of FBE by H, the area of the main electrode 11 is obtained,
This shows that multiplying the denominator by H becomes the volume of the main electrolysis chamber. In particular, it is preferable to satisfy this condition when a low-concentration metal contained in wastewater is recovered by electrolysis. However, if the cross-sectional area (PQcm ² ) of the gas discharge part becomes larger than the cross-sectional area (DWcm ² ) of the main electrolysis chamber, adverse effects such as an unnecessary increase in installation area occur.
That is, it is desirable to design so that PQ / DW is 0.4 or less.

The distance (electrode distance = (WP) / 2) between the electrode surface 11A, which is the inner side surface of the box-shaped electrolytic cell serving as the main electrode chamber, and the auxiliary electrode 13 is preferably 1 to 10 cm. In particular, 1.5 to 4 cm is preferably used.

The height H (cm) of the electrolytic cell is preferably 20 to 200 cm from the viewpoint of maintenance and the like.

FIG. 7 is a side sectional view of the fluidized bed electrolytic cell of FIG.
FIG. 8 which is a cross-sectional view of FIG. 8 shows an example using the fluidized-bed electrolytic cell 10 of the present invention. FIG. 5 shows a fluidized-bed electrolytic cell according to the present invention.
As shown in the perspective view of FIG. 1, the electrolytic cells shown in FIGS. 1, 2, 3, and 4 can be made into one unit, and a plurality of the electrolytic cells can be arranged in parallel according to a required processing capacity. The fluidized bed electrolytic cell 10 of the present invention is excellent in that such scale-up can be easily performed.

The method of the present invention and the fluidized bed electrolyzer 10 are used for collecting and removing metals, purifying metals, plating on granules,
Decomposition of organic compounds or cyanide compounds.

In the case of recovering / removing or purifying a metal or plating a granular material, the side surface of the box-shaped electrolytic cell is connected to the main electrode 11 of the cathode.
Here, the anode covered with the diaphragm 15 as the auxiliary electrode 13 is inserted. The inside of the box-shaped electrolytic cell is filled with the conductive particles 14A, and this serves as a main electrolytic chamber. Therefore, the conductive particles 14A serve as a cathode.

When the fluidized-bed electrolytic cell 10 of the present invention is used to decompose organic substances or decompose a cyanide or the like by utilizing anodic oxidation, the side surface of the box-shaped electrolytic cell serves as an anode, and an auxiliary electrode is provided therein. As 13, the cathode covered with the diaphragm 15 is inserted. Then, the conductive particles 14 are placed inside the box-shaped electrolytic cell.
This is the main electrolytic chamber after A is filled. In this case, the conductive particles 14A serve as an anode.

When the cathode particles are used, the material may be a carbon-based material such as graphite, glassy carbon, or activated carbon, as well as platinum, gold, silver, copper, nickel, tin, lead, or the like.
Conductive materials such as metals or alloys thereof and oxides thereof are used. Furthermore, these conductive materials are graphite,
Those coated on particles made of various resins such as activated carbon, glass, ceramics, and polystyrene can also be used. When anode particles are used, particles obtained by coating a particle selected from graphite, glass, ceramics, resin, metal, and the like with a noble metal, a noble metal oxide, lead, or the like can be used.

The particles used as the fluidized bed 14 have a particle diameter of 0.0
Those having a thickness of 5 to 3.0 mm are used, preferably 0.1 to 3.0 mm.
A 1.0 mm one is used. The specific gravity is 1.1 to
Those having a value of about 3.0 are preferably used. It is desirable that the particle diameter and weight of the particles used are as uniform as possible in order to maintain a stable fluidized state.

In the case of recovering the metal, the metal is electrolytically deposited on the particles. For this reason, the apparent specific gravity of the particles is increased. Therefore, it is preferable to increase the flow rate of the processing liquid accordingly and maintain the optimum flow state.

Main electrode 11 and auxiliary electrode 13 (cathode or anode)
The materials of are graphite, stainless steel, titanium,
Commonly used electrode materials such as platinum or titanium coated with a noble metal oxide can be used. In particular, in the case of collecting and removing metals, titanium or platinum-coated titanium, platinum-iridium-coated titanium is preferably used for the box-shaped electrolytic cell (cathode), and platinum-coated titanium or platinum-iridium-coated titanium is preferably used for the anode.

The diaphragm 15 for separating the conductive particles 14A and the auxiliary electrode 13 in the main electrolysis chamber may be any as long as it allows ions or electrolyte to pass without passing through the particles.
In the case of a porous membrane, the porous membrane has a pore size equal to or smaller than the particle size, and preferably 10 to 100 μm. The material of the diaphragm is preferably a non-conductive organic compound such as polytetrafluoroethylene, polypropylene, polyethylene or nylon, or a non-conductive inorganic compound such as glass fiber or porous ceramic. Further, the diaphragm 15 may have an ion exchange function.

The auxiliary electrode 13 is preferably formed in a perforated shape and closely adhered to the diaphragm 15 in order to discharge gas generated on the electrode to the inside of the electrode. For example, the perforated auxiliary electrode 13 is preferably made of an expanded mesh, a plate provided with holes, a sintered body, a porous body, or the like.

The liquid to be treated is sent to the electrolytic cell from the lower part,
While maintaining the flowing state of the conductive particles arranged in the box-shaped electrolytic tank by the ascending flow, the box-shaped electrolytic tank as the main electrode 11 and the auxiliary electrode 13 are energized to remove or recover the metal. . This flow state is a state in which the processing liquid passes through the gap while the particles in the main electrolytic chamber repeatedly contact and separate from each other. The electrolytic treatment is preferably performed while the fluidized state is expanded so that the apparent volume becomes 105% to 150% by the ascending flow with respect to the apparent fluidized bed volume in the stationary state when the water supply is stopped.

When the electrolysis is performed in this state, the electrolysis is performed on the particle surface of the main electrode 11 in the box-shaped electrolytic cell, so that an efficient treatment can be performed.

The temperature of the water to be treated during the electrolytic treatment is 20
It is preferred to process at ~ 70 ° C.

The height H (cm) of the box-shaped electrolytic cell is preferably at least equal to or higher than the height Hf (cm) of the fluidized particles. It is desirable that H is about 1.1 to 1.8 times Hf. The height of the auxiliary electrode is preferably at least equal to or higher than the height Hf (cm) of the particles in the fluidized state, and more preferably equal to or higher than the height H (cm) of the box-shaped electrolytic cell.

As shown in the partial perspective view of FIG. 5 or the side sectional view of FIG. 6, a plurality of such box-shaped electrolytic cells are arranged in parallel according to the required processing capacity. This makes it easy to scale up without having to change the electrolysis conditions or reconsider.

It is desirable to have a processing liquid discharge section for smoothly discharging the liquid to be processed at the upper portion of the electrolytic cell, and this section reduces the linear velocity of the liquid supply so that particles can be easily separated from the upward flow. It is desirable to design it to have a wide cross section. Since this part does not participate in electrolysis, it is made of a non-conductive material, for example, a vinyl chloride resin, an acrylic resin, a Teflon resin, glass, or the like is used. In particular, it is desirable to be formed of a transparent resin. When a plurality of box-shaped electrolytic cells are arranged in parallel as described above, the processing liquid discharge portion can be formed integrally as shown in FIG. 5 or FIG.

When the electrolytic treatment is performed in the fluidized bed electrolytic cell 10, an electrolytic gas is generated. The gas generated in the fluidized bed 14 becomes large bubbles inside the fluidized bed 14 and may locally blow up particles in the fluidized bed 14. Alternatively, air bubbles may adhere to the particles and float on the upper part. Therefore, there has been a problem that the particles flow out of the electrolytic cell 10. Therefore, as a result of intensive studies, it was found that the particles 14
It has been found that the problem can be solved by providing a barrier plate 18 above which the water to be treated and the electrolytic gas can pass but the particles cannot pass.

The barrier plate 18 may be a perforated plate, a porous plate, a net, or the like. This makes it possible to prevent the particles from flowing out of the electrolytic cell even when the particles are blown up by local blowing of the electrolytic gas. In the electrolytic cell shown in the side sectional view of FIG. 7, a net for preventing outflow of particles is provided as a barrier plate 18 above the fluidized bed 14. Although a non-conductive material is used for the barrier plate 18, a material obtained by applying the same potential as the main electrode 11 to the conductive material may be used.

For the purpose of recovering / removing or purifying the metal, the target metal is electrolytically deposited on the cathode particles in the main electrode chamber. Therefore, the target metal can be taken out and the metal can be recovered. Therefore, it is desirable to provide an outlet 33 or a discharge valve 34 for the particles 14A in the main electrolysis chamber below the fluidized bed electrolyzer 10. Further, it is preferable that the particle take-out port 33 be provided on the short side of the fluidized bed electrolytic cell 10 because it does not hinder the installation of a plurality of electrolytic cells.

The deposited metal can be recovered by re-dissolving it with an acid or the like, but can also be recovered by melting it in a blast furnace or the like. When the particles are recovered by dissolving them in an acid or the like, the particles can be reused, and the recovered liquid has a high concentration and a small amount, and can be economically recovered.

Alternatively, the polarity of the applied voltage may be reversed in order to redissolve the metal deposited on the particles, and the metal deposited on the particles may be redissolved by circulating with a small amount of processing liquid.

When used for the decomposition of an organic compound or a cyanide compound, they do not precipitate on the anode particles.
In particular, no separation operation is required. However, if scale or the like deposited on the auxiliary electrode serving as a cathode hinders electrolysis, it may be necessary to periodically wash the scale. Alternatively, when the deposited metal is easily peeled from the particles,
A filter 26 can be provided at the subsequent stage of the fluidized bed electrolytic cell 10 to recover as fine metal powder.

When the fluidized-bed electrolytic cell 10 of the present invention is used for collecting and removing metals, the current density on the electrode surface 11A, which is the side surface of the box-shaped electrolytic cell serving as the main electrode 11, is 1.5 A / dm ² and the main electrode 11 is used. It is preferable that the operation is performed so that the current concentration of the fluidized bed 14 that is in contact with the liquid is 3 A / L or more per fixed particle volume. If the current density or current concentration is low, it is difficult to efficiently collect and remove the metal.

The fluidized-bed electrolytic cell 10 of the present invention is particularly effective for recovering and removing low-concentration metals contained in waste liquid.
It is possible to efficiently collect and remove metals contained at a very low concentration of 0 ppm or less, particularly 100 ppm or less, to 10 ppm or less or 1 ppm or less.

Another embodiment of the present invention also provides a method for recovering nickel. The concentration of nickel contained in the wastewater generated in the nickel plating step is usually as low as several tens of ppm, but the amount of the wastewater is large, so that the load on the ion exchange resin for treating the wastewater is large. An attempt was made to treat such effluent in a fluidized bed electrolytic cell, but the concentration of nickel could not be sufficiently reduced.

Therefore, as a result of intensive studies to solve this problem, it was confirmed that the nickel content in the wastewater can be reduced to 10 ppm or less by maintaining the pH of the wastewater during electrolysis at 6 to 10. Was. More preferably, by maintaining the pH of the treatment solution at 7.7 to 9.2, the nickel content in the wastewater can be reduced to 1 ppm or less. When the pH is 7.7 or higher, nickel can be recovered to a low concentration. However, when the pH exceeds 9.2, it is confirmed that the activated carbon used as particles is broken down during electrolysis and the treatment liquid is colored black. It has been found that it is preferable to treat at a pH of 7.7 to 9.2. On the strong alkali side, nickel ions in the wastewater are converted to hydroxides, which is not preferable.

Also, at this time, in the electrolytic cell of the present invention, when the distance between the cathode of the electrode surface 11A which is the inner side surface of the box-shaped electrolytic cell and the anode which is the auxiliary electrode 13 is 4 cm or less, high treatment is performed. The nickel concentration could be reduced with efficiency. The nickel plating wastewater tested contained components such as tin ion, sulfate ion, tartaric acid, and ammonium sulfate. Was also recoverable. Further, it was confirmed that the electrolytic solution shifted to the acidic side as the metal ions decreased during electrolysis for collecting and removing the metal. In particular, when it is desired to continue electrolysis under conditions of neutral to weak alkali such as nickel, it is necessary to add an alkali such as sodium hydroxide for pH adjustment. However, when the purpose of the treatment is not only the recovery and removal of metals but also the reuse of wastewater, it is not preferable to add a new electrolyte. for that reason,
As a result of intensive studies on a method of solving this, in a method of recovering metal contained in wastewater in the fluidized bed electrolytic cell 10,
A part or all of the treatment liquid before or after passing through the electrolytic cell 10 is treated with the anion exchange resin 27, so that the treatment liquid is treated so that the pH of the treatment liquid becomes a predetermined value. I found a way to do it. This makes it possible to control the fluctuation of pH due to electrolysis, and to provide a water treatment method in which water can be easily reused while preventing fluctuation or reduction in electrolysis efficiency. .

Next, the present invention will be described based on examples.
Embodiments of the present invention are not so limited.

Example 1 A box-shaped electrolytic cell of the present invention as shown in FIGS.
Was 50 cm, the width D was 20 cm, and the width W was 4 cm. A 2 mm thick titanium plate was used for the box-shaped electrolytic cell serving as the cathode. The auxiliary electrode serving as the anode has two 1 mm thick platinum-coated titanium meshes (height H50 cm, width Q16c).
m) held at P = 0.7 cm at intervals of 0.5 cm. This gap was used as an electrolytic gas discharge passage, which was covered with a diaphragm made of glass fiber cloth. The main electrolysis chamber was filled with 2 liters of activated carbon beads (φ 0.7 to 0.8 mm).

Using this, the processing apparatus shown in FIG. 9 was prepared. Plating wastewater (pH 6.0) containing 80 ppm of tin and additionally containing sulfuric acid and other ions was fed from the bottom of the electrolytic tank, and a DC voltage was applied by a DC power supply 40 to perform electrolysis at a constant current of 20 A. Water storage tank 2 having pH meter 23
50 liters of the water to be treated in 1 was treated by the pump 25 by circulation for 1 hour.

Table 1 shows the results.

It was confirmed that the use of the electrolytic cell of the present invention efficiently recovered tin in wastewater. or,
The electrolyzed water after the treatment was shifted to the acidic side up to about pH 4.

The electrolytic cell of the present invention can be used for increasing the processing amount.
As shown in FIG. 6, two or more electrolytic cells can be added, and the same result was obtained even when the treatment liquid volume was set to 100 liters. It was confirmed that scale-up could be easily performed.

[0062]

[Table 1]

Example 2 A box-shaped electrolytic cell according to the present invention as shown in FIGS.
Was 50 cm, the width D was 30 cm, and the width W was 5 cm. A 2 mm thick titanium plate was used for the box-shaped electrolytic cell serving as the cathode. An auxiliary electrode serving as an anode has two platinum-coated titanium meshes having a thickness of 1 mm (height H is 50 cm and width Q is 26).
cm) at 1 cm intervals (P = 1.2 cm). This gap serves as an electrolytic gas discharge passage,
This was coated with a diaphragm. The main electrolytic chamber was filled with activated carbon beads (φ0.7 to 0.8 mm) and 3 liters.

A test device shown in FIG. 9 was prepared. A plating wastewater (pH 6.0) containing 30 ppm of nickel and further containing sulfuric acid and other ions is sent from the bottom of the electrolytic cell,
DC voltage was applied by the DC power supply 40, and electrolysis was performed at a constant current of 30A. 100 L of water to be treated in a water storage tank 21 having a pH meter 23 was circulated by a pump 25. During the treatment, a NaOH solution was appropriately added to the water to be treated in the water storage tank 21 in order to maintain the pH within a predetermined range.
As a comparative example, electrolysis was performed without controlling the pH.

Table 2 shows the results.

It was confirmed that nickel was efficiently recovered from the wastewater by controlling the pH using the electrolytic cell of the present invention. When the pH is 6 or less, it is difficult to recover a low concentration of nickel.

[0067]

[Table 2]

Example 3 Using the electrolytic cell of the present invention used in Example 1, some or all of the water to be treated after passing through the electrolytic cell can pass through the anion exchange resin 27 as shown in FIG. It was arranged as follows. A plating wastewater containing 30 ppm of nickel and 40 ppm of tin and further containing sulfuric acid and other ions (pH 6.
0), an electric conductivity of 60 mS / m is fed from the bottom of the electrolytic cell, a DC voltage is applied by a DC power supply 40, electrolysis is performed at a constant current of 20 A, and a water storage tank 21 having a pH meter 23 is provided.
50 liters of water to be treated in the
Time processed. While monitoring the pH of the liquid to be treated in the water storage tank 21, a part of the liquid to be treated after passing through the electrolytic tank was sent to an anion exchange resin and maintained at pH 7.7 to 8.3.

Table 3 shows the results.

[0070]

[Table 3]

It was confirmed that by using the electrolytic cell of the present invention and the anion exchange resin 27 in combination, it was possible to efficiently treat nickel in wastewater, and it was confirmed that the method was excellent as a method for regenerating wastewater. .

[0072]

According to the present invention, a fluidized-bed electrolytic cell having excellent treatment efficiency and a water treatment method using the same are provided. In particular, efficient collection and removal of low-concentration metals in wastewater has become possible. .

In addition, it was possible to provide a method for efficiently recovering and removing nickel particularly contained in wastewater at a low concentration.

[Brief description of the drawings]

FIG. 1 is a horizontal sectional view of a fluidized-bed electrolytic cell of the present invention.

FIG. 2 is a side sectional view of the fluidized bed electrolytic cell of the present invention.

FIG. 3 is a front sectional view of the fluidized bed electrolytic cell of the present invention.

FIG. 4 is a perspective view of a fluidized bed electrolytic cell of the present invention.

FIG. 5 is an explanatory view showing one example of a water treatment method using the fluidized bed electrolytic cell of the present invention.

FIG. 6 is a side cross-sectional view when the fluidized-bed electrolytic cell of the present invention is provided in two rows.

FIG. 7 is a side sectional view showing another embodiment of the fluidized bed electrolytic cell of the present invention.

FIG. 8 is a sectional view taken along line AA of FIG. 7;

FIG. 9 is a side sectional view showing another embodiment of the fluidized bed electrolytic cell of the present invention.

FIG. 10 is a side sectional view showing still another embodiment of the fluidized bed electrolytic cell of the present invention.

DESCRIPTION OF SYMBOLS 10 Fluidized bed electrolysis cell 11 Main electrode 13 Auxiliary electrode 14 Fluidized bed 14A Conductive particles (particles, beads) 15 Diaphragm 17 Support plate 18 Barrier plate 19 Gas discharge path 26 Filter 27 Ion exchange resin 31 Discharge of treatment liquid Part 33 Particle outlet 34 Valve

Claims (10)

[Claims] 1. A main electrode comprises the inner side surface of a box-shaped electrolytic cell, an auxiliary electrode comprises a plate-like or mesh-like electrode covered with a diaphragm, and the auxiliary electrode faces the inside of the box-shaped electrolytic cell as the main electrode. It is arranged, and the conductive particles are filled in such a state that the box-shaped electrolytic cell can come into contact with the main electrode, and the bottom surface of the box-shaped electrolytic cell can substantially pass through the water to be treated, but the conductive particles do. It consists of a support that cannot be processed,
A fluidized bed electrolytic cell for applying a DC voltage between the main electrode and the auxiliary electrode by making the conductive particles in a fluidized state, wherein one or more electrolytic cells are arranged in parallel. 2. The main electrode comprises an inner side surface portion of a box-shaped electrolytic cell, and the auxiliary electrode comprises at least two perforated plate electrodes or mesh electrodes covered with a diaphragm, formed by the at least two electrodes. The auxiliary electrode is disposed so as to allow gas generated on the auxiliary electrode to pass through the gap, and the auxiliary electrode is disposed to face the inside of the box-shaped electrolytic cell as the main electrode, The tank is filled with conductive particles in a state where it can contact the main electrode, and the bottom surface of the box-shaped electrolytic tank is made of a support that can substantially pass water to be treated but cannot pass conductive particles. Send more water to be treated,
A fluidized bed electrolytic cell for applying a DC voltage between the main electrode and the auxiliary electrode by making the conductive particles in a fluidized state, wherein one or more electrolytic cells are arranged in parallel. 3. The fluidized-bed electrolytic cell according to claim 1, wherein the electrolytic cell is an FB obtained by the following equation (1).
A fluidized-bed electrolytic cell characterized by having an E value of 0.2 or more. FBE = 2 (D + W) / (DW-PQ) Equation (1) P: Thickness of auxiliary electrode part including internal space (cm) Q: Width of auxiliary electrode (cm) W: Box-shaped main electrode chamber Length of short side (cm) D: Length of long side of box-shaped main electrode chamber (cm) 4. A metal recovery and removal method for recovering or removing metal from wastewater using the fluidized bed electrolytic cell according to claim 1, wherein the main electrode is a cathode. Wherein the current density at the side of the box-shaped electrolytic cell is 1.5 A / dm ² or more, and the fluidized bed in contact with the main electrode is operated at a current concentration of 3 A / L or more. Metal recovery and removal method using an electrolytic cell. 5. A water treatment method for recovering or removing a metal using the fluidized bed electrolytic cell according to any one of claims 1 to 3, wherein the metal concentration is 500 ppm or less and the electric conductivity is less. A water treatment method using a fluidized bed electrolytic cell, wherein wastewater having a degree of 100 mS / m or less is treated. 6. A method for recovering or removing contained metal components by treating treated water containing metal ions in a fluidized-bed electrolytic cell. A method for recovering and removing metals using a fluidized bed electrolytic cell, wherein a part or all of the liquid before or after passing through the bed electrolytic cell is treated with an anion exchange resin. 7. A method for recovering or removing nickel contained in waste water at a nickel content of 500 ppm or less in a fluidized bed electrolytic cell so as to have a concentration of 10 ppm or less. A method for recovering and removing nickel, wherein the method is maintained at 6 to 10. 8. A method for recovering or removing nickel contained in waste water at a nickel content of 500 ppm or less in a fluidized bed electrolytic cell so as to be 5 ppm or less,
A method for recovering and removing nickel, wherein the pH of the treatment liquid is maintained at 7.7 to 9.2. 9. A method for recovering or removing nickel contained in wastewater having a nickel content of 100 ppm or less and an electric conductivity of 100 mS / m or less, using a fluidized bed electrolytic cell, wherein the pH of the treatment liquid is adjusted. A method for recovering and removing nickel from wastewater using a fluidized bed, wherein the treatment is performed while maintaining the pH at 7.7 to 9.2. 10. A method in which a main electrode comprises an inner side surface portion of a cylindrical or box-shaped electrolytic cell, and an auxiliary electrode covered with a diaphragm is disposed facing the inside of the main electrode so that the conductive particles can be brought into contact with the main electrode. Is filled, and the bottom surface of the electrolytic cell is made of a support that can substantially pass through the water to be treated, but cannot pass through the conductive particles. A fluidized bed electrolytic cell for applying a DC voltage between the main electrode and the auxiliary electrode, wherein a barrier plate through which the water to be treated and the electrolytic gas can pass but the particles cannot pass above the particles in the fluid state. A fluidized-bed electrolytic cell, which is provided.