JP2001149941A - Treating device of metal-containing waste water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treating device of metal-containing waste water for treating waste water containing metal with high efficiency and recovering the metal in the waste liquid at a high content ratio. SOLUTION: The treating device of metal-containing waste liquid is provided with a waste liquid treating tank for housing the waste liquid containing metal, a single or plural positive electrode plates installed to immerse it or them in the waste liquid, a single or plural negative plates being rotatable by being confronted with the positive electrode plates and connected with a revolving shaft, and a scraper fox peeling off deposition deposited on the negative electrode plates and obtaining a recovery product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for treating a waste liquid containing a metal such as a plating waste liquid.

[0002]

2. Description of the Related Art As a treatment method for removing metals from a waste liquid containing metals such as plating waste liquid, there is a neutralization precipitation method. This is a method in which the pH of the waste liquid is adjusted to a neutral range by adding an acid or an alkali, and the metal dissolved in the waste liquid is precipitated and separated as a hardly soluble hydroxide. There is also a chelate addition treatment method in which a chemical solution that produces a metal and a chelate compound is added. In addition, there is an electrodeposition treatment method in which a positive electrode plate and a negative electrode plate are immersed in a waste liquid containing a metal and energized. This is a method in which a metal dissolved as an ion in a waste liquid is reduced to a metal having no charge on the negative electrode plate to precipitate on the negative electrode plate, and is separated and recovered from the negative electrode plate.

[0003]

Among the conventional techniques, in the neutralization precipitation method, the equipment required for the apparatus is small and the cost of the apparatus is low. However, when the pH of the waste liquid is a strong acid or a strong alkali, a large amount of chemical solution is required. It is necessary to neutralize with, there is a possibility that the operating cost may be expensive, and also, when the metal hydroxide sludge generated by this treatment is recovered as a valuable resource, the metal hydroxide sludge has a high water content. In addition, a device that performs dehydration or drying is required, and furthermore, the metal hydroxide sludge obtained by this means that the metal is present not as a simple substance but as a hydroxide, and depending on the type of waste liquid, other than a metal hydroxide. Due to the mixture of substances, the content of metals is low, the unit price when selling as valuable resources becomes very low, and eventually the transportation cost becomes higher, and collection costs may occur. There is a problem that had.

[0004] In addition, in the chelate addition treatment method, since these chemicals called chelating agents are expensive, the operating cost is high, and when the produced metal chelate compound sludge is recovered as valuables, it is neutralized. As in the case of the sedimentation method, there is a problem that a collection cost is required.

[0005] In addition, the electrodeposition treatment method does not require a large amount of a chemical solution and has a low water content in the recovered material, so that a device for performing dehydration and drying when recovering valuable resources is unnecessary, and the metal in the recovered material is not required. Since the content rate is high and the unit price when selling it as a valuable resource is expensive, it is superior to the above two methods, but the work of stripping the precipitate on the negative electrode plate requires labor and time. At present, very few examples have been implemented for that purpose.

The present invention relates to an improvement in an electrodeposition treatment method, and more particularly to an apparatus for treating a metal-containing waste liquid which is excellent in efficiency and can treat a metal-containing waste liquid and can recover a high content of metal in the waste liquid. The purpose is to provide.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to a waste liquid treatment tank containing a waste liquid containing a metal, a single or a plurality of positive plates installed so as to be immersed in the waste liquid, and a plate facing the positive plate. By being connected by a rotating shaft, a rotatable single or multiple negative plates, and a metal-containing waste liquid treatment device equipped with a scraper that separates deposits deposited on the negative plates to obtain a recovered product is there.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.
It will be described based on. The waste liquid 8 is a waste liquid containing a metal such as a plating waste liquid. Although it can be applied regardless of the concentration of the metal, it is desirable that an appropriate amount of electrolyte is dissolved in the waste liquid in order to conduct electricity in the waste liquid. The waste liquid treatment tank 5 has a capacity that accommodates the waste liquid 8 and can immerse a part of the positive electrode plate 1 and a part of the negative electrode plate 2. Further, in order to keep the metal concentration distribution in the waste liquid treatment tank 5 constant, it is preferable to stir the inside of the tank by means such as aeration (not shown) as necessary. The positive electrode plate 1 is provided so as to face the negative electrode plate 2 in the waste liquid treatment tank 5. If the number of the electrode plates becomes complicated, the positive electrode plate 1 can be provided alternately with the negative electrode plate 2. Positive electrode plate 1
The material varies depending on the type of waste liquid to be treated, but a corrosion-resistant metal plate or carbon plate can be used. Although the carbon plate is lightweight and inexpensive, depending on the waste liquid 8, carbon may be dissolved in the waste liquid 8 and the positive electrode plate 1 may be severely worn. In such a case, it is desirable to use an insoluble metal plate such as titanium. The negative electrode plate 2 includes a waste liquid treatment tank 5
It is provided so as to face the positive electrode plate 1 and is rotatable while being supported by the rotating shaft 4. When the number of electrode plates is complicated, they are supported by the same rotating shaft 4 and provided alternately with the positive electrode plate 1. As the material of the negative electrode plate 2, a corrosion-resistant metal plate can be used, and stainless steel is particularly desirable. The rotating shaft 4 also has a role of a conducting wire for supplying a current to the negative electrode plate 2, and its outer periphery is covered with an insulator to prevent a short circuit near the positive electrode plate 1. The precipitate 6 is peeled off by the scraper 3 when the negative electrode plate 2 rotates. As the scraper 3, a steel plate can be applied. Further, the scraper 3 is installed with an inclination, and also has a role of transferring the collected material 7 separated from the negative electrode plate 2 to the outside of the device.

[0009]

EXAMPLE An example in which a plating waste liquid is actually treated will be described. Table 1 shows the contents of the waste liquid to be treated.

[0010]

[Table 1]

The specifications of the apparatus will be described below.・ Waste liquid treatment tank: Size = 300mm × 900mm × 500mm, effective volume = 110 liter ・ Positive electrode plate: Shape = semicircle with diameter of 800mm, thickness = 20mm, material = titanium, number of sheets = 2, effective electrode plate area = 0.75 m ² · Negative electrode plate: Shape = disk with a diameter of 800 mm, thickness = 30 mm, material =
Stainless steel, number of sheets = 2, effective electrode plate area = 0.75 m ²

Most of the positive electrode plate is immersed in the waste liquid 8 of the waste liquid treatment tank 5 shown in FIG. 1, and the lower half of the negative electrode plate is immersed in the waste liquid. The number of the positive electrode plate and the negative electrode plate is two, respectively.
Since the surfaces of the positive electrode plate and the negative electrode plate facing each other in the waste liquid are respectively three, the area of the effective electrode plate is three times the area of the positive electrode plate. In such an apparatus, a DC current of 600 A was applied between the positive electrode plate and the negative electrode plate. The nickel concentration in the treated water was 450 mg / l after 2 hours (93% removal rate).
%) 110 mg / l (removal rate 98%) after 4 hours,
After 8 hours, the concentration had dropped to 20 mg / l (a removal rate of 99.7%). The nickel content of the recovered material separated and recovered by the scraper was 8% by weight based on the dry weight of the recovered material.
2%.

According to the apparatus for treating a metal-containing waste liquid, a single or a plurality of rotatable negative electrode plates and a scraper for removing a substance deposited on the negative electrode plate to obtain a recovered material are provided. The operation of separating the precipitate on the negative electrode plate can be automated, and a waste liquid containing a metal component can be treated without using a large amount of a chemical solution. In addition, the collected material collected during the treatment has a low water content and a high metal component content, and thus can be collected as a valuable material without performing post-treatment such as dehydration or drying.

[0014]

As described above, according to the present invention, it is possible to treat highly efficient waste liquid containing metal,
It is possible to provide an apparatus for treating a metal-containing waste liquid capable of recovering a high content of metals in the waste liquid.

[Brief description of the drawings]

FIG. 1A is a perspective view showing a main part of an embodiment of the present invention, and FIG. 1B is a front view showing an outline of the entire apparatus.

[Explanation of symbols]

 1. 1. positive electrode plate Negative electrode plate 3. Scraper 4. Rotation axis 5. Waste liquid treatment tank 6. Precipitate 7. Collected items 8. Waste liquid

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshinobu Makita 1250 Shimoedori, Shimodate-shi, Ibaraki Prefecture Within Hitachi Chemical Technoplant Co., Ltd. (72) Inventor Masashi Yamamoto 1250 Shimoedori, Shimodate-shi, Ibaraki Hitachi Techno Plant Co., Ltd. F term (reference) 4D061 DA08 DB18 DC20 EA05 EB20 EB28 EB30 EB33 ED20 4K001 AA19 BA21 DB21

Claims (1)

[Claims] 1. A waste liquid treatment tank containing a waste liquid containing metal,
A single or a plurality of positive plates placed so as to be immersed in the waste liquid, a single or a plurality of negative plates which are rotatable by being connected to a rotating shaft facing the positive plate, and on the negative plate; An apparatus for treating a metal-containing waste liquid, comprising: a scraper for separating a precipitate deposited on a surface to obtain a recovered product.