JP2001234377A - Equipment for cleaning metallic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an equipment for cleaning a metallic material with which formed bubbles are efficiently broken, the defoamed solution is reutilized as a cleaning solution, and the lowering of detergency after cleaning is appropriately prevented. SOLUTION: This equipment for cleaning a metallic material is provided with a cleaning tank for cleaning a metallic material with grease, or the like, stuck on its surface, a circulating tank for circulating a cleaning solution between it and the cleaning tank, a means for sucking the bubbles of the cleaning solution in the circulating tank, a defoaming box supplied with the bubbles sucked by the suction means and breaking the bubbles, a tank supplied with the defoamed solution generated in the defoaming box, separating and removing the impurities in the solution and a pipeline for supplying the solution freed from the impurities in the tank to the circulating tank.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for cleaning a metal material such as a steel strip, and more particularly to a method for removing bubbles generated during cleaning and reusing a liquid produced by the defoaming as a cleaning liquid. It is related to the equipment that was used.

[0002]

2. Description of the Related Art Generally, in cleaning equipment for steel strips and the like,
A method in which an alkaline aqueous solution such as caustic soda or orthosilicate soda is used as a cleaning liquid and a steel strip or the like is immersed in the cleaning liquid, a method in which the cleaning liquid is sprayed on the steel strip or the like, or a state where the steel strip or the like is immersed in the cleaning liquid or The method of electrolysis in the state where the cleaning liquid is sprayed on the steel strip or the like, and the method of brushing the steel strip or the like in the state where the cleaning liquid is sprayed on the steel strip or the like by immersing the steel strip or the like in the cleaning liquid or the like, by combining the method such as Degreasing and washing of rolling oil and the like adhering to the surface are performed. In this degreasing cleaning, a chemical reaction occurs between the rolling oil and the like and a cleaning solution such as an alkaline aqueous solution, and a large amount of bubbles is generated in a cleaning tank or a circulating tank of the cleaning equipment. Invite. For this reason, it is necessary to replenish the cleaning liquid, and the cost increases due to the purchase cost of the cleaning liquid. Further, since the cleaning liquid is often used after being heated from normal temperature to ensure cleaning properties, a large amount of heat energy such as steam is consumed with the supply of the cleaning liquid.
In addition, since the foam overflows out of the tank, the working environment around the tank is remarkably deteriorated, and a disposal cost for waste liquid is required. In order to prevent the foam from overflowing, it is common to add an antifoaming agent to the cleaning solution. The cost increases due to the purchase cost of In addition, even if a defoaming agent is added, the defoaming does not become 100%, and it does not become a decisive factor for defoaming measures.

An apparatus for solving such a problem is disclosed in the following publication. Japanese Unexamined Patent Publication (Kokai) No. Hei 3-153887 discloses that a foamed alkaline cleaning liquid is stored in a storage tank, bubbles generated in the upper part of the storage tank are led to an overflow tank, and foams in the overflow tank are collected. A device for spraying atomized water and defoaming is disclosed. Also, JP-A-6-4954
No. 4 discloses an apparatus for defoaming by blowing hot air at 50 ° C. to 300 ° C. on foams generated in a steel strip degreasing cleaning tank and a cleaning liquid circulation tank.

On the other hand, an apparatus for reusing an antifoaming liquid as a cleaning liquid is disclosed in Japanese Patent Application Laid-Open No. 11-36090. In this method, foam generated in the cleaning tank is sent to a defoaming box by an ejector to defoam the liquid, the liquid generated by the defoaming is stored in a circulation tank, and the stored liquid is returned to the cleaning tank as a cleaning liquid by a circulation pump. is there.

[0005]

However, as in the apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 3-153887, the spray liquid is sprayed on the foam, and a large amount of spray water is required. There is a problem that the concentration of is reduced. Also,
The atomized water collides with the surface of the cleaning liquid that has been defoamed by spraying the atomized water, and foaming occurs, so that complete defoaming cannot be performed. For this reason, when the generation of bubbles is large, it is insufficient to prevent the overflow of the bubbles from the overflow tank. Also,
A device that blows hot air onto foam to defoam it, such as the device disclosed in Japanese Patent Application Laid-Open No. 6-49544, requires a large amount of hot air to maintain the defoaming ability commensurate with foaming. There was a problem that complete defoaming was not possible.

On the other hand, in the apparatus disclosed in Japanese Patent Application Laid-Open No. 11-36090, it is possible to discharge the generated foam in a larger amount than before, and to eliminate almost 100% of the discharged foam. However, oil and iron powder are mixed. Since the liquid after defoaming is returned to the circulation tank as it is, there is a problem that the cleaning ability of the cleaning liquid is reduced with time.

According to the present invention, the generated bubbles are efficiently defoamed,
The defoaming liquid generated by defoaming can be reused as a cleaning liquid,
Moreover, it is an object of the present invention to provide a metal material cleaning facility capable of appropriately preventing a reduction in cleaning performance after cleaning.

[0008]

SUMMARY OF THE INVENTION The cleaning equipment for metal materials of the present invention has the following features.

(1) A washing tank for washing a metal material having oils and the like adhered to the surface, a circulation tank for circulating the washing liquid between the washing tank, and a bubble of the washing liquid in the circulation tank. A foam suction means for sucking, a foam sucked by the foam suction means, and a defoaming box in which foam is broken; and a liquid generated by foam breaking in the defoaming box is supplied. Cleaning equipment for metal material, comprising: an impurity separation tank for separating and removing impurity components therein; and a piping system for supplying a liquid from which the impurity components have been separated and removed in the impurity separation tank to the circulation tank. .

(2) The circulation tank has a partition wall whose lower part is immersed in the cleaning liquid stored in the tank, and one of the sections divided by the partition wall receives the cleaning liquid from the cleaning tank. The cleaning equipment for a metal material according to the above (1), wherein:

(3) The impurity separating tank described above, wherein the impurity separating tank has a plurality of separation sections divided by a plurality of partition plates and a plurality of weirs vertically provided from the top of the tank. Cleaning equipment for metal materials as described in.

(4) The foam suction port of the foam suction means moves up and down in accordance with the level of the washing liquid in the circulation tank in the vertical direction. Cleaning equipment for metal materials as described.

(5) The above-mentioned (3), wherein the impurity separation tank having the separation section has an effective volume such that the residence time of the liquid in the separation section is at least 15 minutes or more.
Or the washing | cleaning equipment of the metal material in any one of (4).

(6) The impurity separation tank having a separation section has discharge means for discharging the impurities separated in each of the separation sections to the outside of the tank for each of the separation sections. 3) The cleaning equipment for a metal material according to any one of the items (3) to (5).

(7) The equipment for cleaning a metal material according to any one of the above (1) to (6), wherein a steam ejector is used as the foam suction means.

(8) A cleaning tank for cleaning a metal material having grease or the like adhering to the surface, a circulation tank for circulating the cleaning liquid between the cleaning tank and the cleaning tank, Foam suction means for suctioning, a foam sucked by the foam suction means is supplied, a defoaming box in which foaming is performed, and a liquid generated by foaming in the defoaming box is supplied,
An impurity separation tank for separating and removing the impurity component in the liquid; and a piping system for supplying a liquid from which the impurity component is separated and removed in the impurity separation tank to the circulation tank. Cleaning equipment.

In the present invention, a liquid containing impurities obtained by defoaming the foam after washing (hereinafter referred to as "defoaming liquid")
Through an impurity separation tank to remove impurities,
Since the obtained liquid is returned to the circulation tank as a recovered cleaning liquid,
The cleaning ability of the cleaning liquid can be maintained for a long time. As a result, the supply amount of the cleaning liquid can be reduced, so that the purchase cost of the cleaning liquid can be reduced. Further, since the supply amount of the cleaning liquid can be reduced, heat energy such as steam necessary for raising the temperature can be reduced. Further, since the bubbles are prevented from overflowing out of the tank, the working environment around the tank is improved, and the cost for treating the waste liquid is unnecessary.

In the following description, the soap content refers to the fatty acid sodium produced by the hydrolysis (saponification) reaction of the rolling oil adhering to the steel strip surface with the alkali in the cleaning solution. Refers to the sum of the unsaponifiable oil component in the rolling oil that does not cause the saponification reaction and the unsaponifiable oil component that is present due to the insufficient saponification reaction in the rolling oil, and the iron component refers to wear powder mainly generated from the surface of the steel strip. Point.

[0019]

FIG. 1 is a schematic view showing an embodiment of the cleaning equipment of the present invention.

FIG. 1 shows a cleaning tank 2 for cleaning a metal material having oil or the like adhered to the surface, a circulation tank 5 for circulating a cleaning liquid 3 between the cleaning tank 2 and a cleaning liquid in the circulation tank. A bubble suction means for sucking the foam of No. 3, a foam sucked by the foam suction means is supplied, and a defoaming box 11 in which foam is broken, and a liquid generated by foam breaking in the defoaming box 11 is supplied. An impurity separation tank 15 for separating and removing impurity components in the liquid, and piping systems 22 and 24 for supplying the liquid from which the impurity components have been separated and removed in the impurity separation tank 15 to the circulation tank 5 are provided.

The cleaning tank 2 is filled with a cleaning liquid for cleaning a steel strip or the like having a surface to which oil or the like has adhered.
Is continuous.

The circulation tank 5 has a cleaning liquid upper space divided into a first section 7 and a second section 8 by a partition wall 6 whose lower part is immersed in the cleaning liquid 3 stored in the tank. Then, the liquid from the cleaning tank 2 is supplied to the first section 7 through the pipe 4.

The foam suction means comprises a foam suction port 9 and an ejector 10 serving as a driving source for foam suction. The foam suction port 9 is provided above the first section 7 of the circulation tank 5. The ejector 10 is connected to the defoaming box 11, to which the pipe connected to the foam suction port 9 and the pipe for the driving fluid are connected. The ejector 10 feeds the foam to the collision plate 12 of the defoaming box 11 at a high speed. As the ejector 10, a steam ejector, an air ejector, or the like can be used.

The defoaming box 11 has a mesh-like collision plate 1 inside.
2 and a partition wall 13. The collision plate 12 is formed of a net-like baffle plate, and the bubbles discharged from the ejector 10 are jetted toward the collision plate 12 and collide. The atmosphere inside the defoaming box is radiating to the atmosphere.

The impurity separation tank 15 includes the defoaming box 11
An antifoaming liquid containing impurities flowing through the pipe 14 through the pipe 14 flows as shown by an arrow, and is suspended from the upper part of the tank in order to perform sedimentation / separation of impurity components in the liquid in a plurality of stages in the flow direction. A plurality of partition plates 16 whose lower portions are immersed in the liquid and weirs 17 erected at the tank bottom are alternately provided along the flow direction of the liquid. Here, the partition plate 16 allows the defoaming liquid to pass from below, and the weir 17 causes the defoaming liquid to overflow from above. Further, the impurity separation tank 15 has an effective volume such that the residence time of the liquid in the separation section is at least 15 minutes or more. Further, the oil and soap 18 and the iron 19 separated in each of the separation sections are discharged out of the tank by the extraction pipe 21 in each of the separation sections. The outlet section C of the impurity separation tank 15 is provided with a level meter 20.

The piping systems 22 and 24 supply the liquid discharged from the liquid discharge side of the impurity separation tank 15 to the recovered liquid circulation pump 2.
3 is supplied to the circulation tank 5.

Next, a process for treating bubbles of the cleaning liquid generated in the cleaning equipment will be described. When the steel strip 1 is degreased and cleaned in the cleaning tank 2 by a method of immersing the steel strip 1 in the cleaning liquid, a liquid layer of the cleaning liquid mixed with the bubbles 30 is formed in an upper layer of the cleaning liquid 3. The cleaning liquid mixed with the foam flows into the first section 7 of the circulation tank 5 through the pipe 4. When the cleaning liquid flows, a large amount of foam 30 is generated by mixing with the cleaning liquid 3 stored in the circulation tank 5, and the foam is used to fill the first compartment. Does not flow into Here, the partition wall 6 of the circulation tank 5 may be omitted, but it is preferable that the partition wall 6 be provided in order to efficiently guide the bubbles to the bubble suction port 9.

The foam 30 has oil and soap 18 and iron 19 together with the washing liquid. The foam 30 in the first section 7 is sucked by the ejector 10 through the foam suction port 9 provided in the first section 7 and is jetted at high speed toward the collision plate 12 of the defoaming box 11. Here, it is desirable that the foam suction port 9 vertically follows the liquid level of the circulation tank. If the bubble suction port 9 follows up and down so as to be directly above the liquid level of the circulation tank, only the bubbles in the first section 7 of the circulation tank can be sucked most efficiently without sucking the cleaning liquid 3. For example, as means for causing the foam suction port 9 to follow the liquid surface level of the circulation tank in the vertical direction, a float body is provided on the liquid surface, and a member connecting the float body and the foam suction port 9 is provided. The foam suction port 9 may be moved up and down.

Here, it is desirable to use a steam ejector as the ejector 10. This is because, when the ejector 10 is used, the foam breaks due to the steam heat as compared to the shear break of the foam by giving kinetic energy to the foam and the collision break of the foam to the collision plate. In addition, efficient foam breaking (or defoaming) is performed, and foam is almost 10
This is because 0% of the bubbles are broken.

Further, as described in Examples described later, as a result of testing the pressure of the steam used in this steam ejector and the state of foam breakage using a steam ejector as the ejector, the steam pressure was 3 to 4 kg / cm. ^{At 2} , it was found that good foam suction and foam breakage were obtained.

The foam collides with the collision plate 12 and breaks into a liquid, which is stored in a liquid pool at the bottom of the defoaming box 11. The defoaming liquid stored at the bottom of the defoaming box 11 is a cleaning liquid mixed with impurities such as oil, soap and iron. The cleaning solution 3a containing this impurity passes through the pipe 14 and passes through the impurity separation tank 15
Flows into the lower part of the entry side section A of FIG.

The cleaning solution containing impurities flowing into the impurity separation tank 15 is inverted under the partition plate 16 as shown by the arrow,
Overflowing the weir 17, entry section A → middle section B → exit section C
It flows in the order of In each section, an oil component and a soap component 18 having a lower specific gravity than the cleaning liquid float on the cleaning liquid 3b,
The sedimentation / separation is performed in which iron 19 having a higher specific gravity than the washing liquid settles at the tank bottom. Floating of impurities in each section
Since sedimentation and separation are performed, the amount of impurities contained in the cleaning liquid decreases in the order of the entrance section A → the intermediate section B → the exit section C,
The cleaning liquid 3c having almost no impurities is separated in the outlet section C,
Collected.

It is to be noted that the plurality of partition plates 16 and the weirs 17 erected on the tank bottom may not be provided, but the plurality of partition plates 1
6 and a weir 17 standing on the bottom of the tank, it is preferable that the section C is provided because the settling and separation can clean the outlet section C.

In each section, for example, every time a predetermined recovery amount or recovery time is reached, oil, soap, etc. 18,
It is desirable that impurities such as iron 19 are discharged to the outside of the tank through the extraction pipe 21 together with the cleaning liquid in each section.

The level of the recovered washing liquid 3c from which the impurities in the outlet section C have been removed is controlled by the level meter 20 to be constant, and is passed through the suction pipe 22, the recovered liquid circulation pump 23 and the discharge pipe 24 to the circulation tank 5. Flows into the second section 8.
Here, a concentration meter is installed in the outlet section C, and the collected cleaning liquid 3c is set.
Is abnormal (extremely low concentration, etc.), the concentration may fluctuate when the collected cleaning liquid 3c flows into the circulation tank 5, so the collected cleaning liquid 3c in the outlet section C is extracted. The gas may be discharged out of the tank by the pipe 21. In addition, a thermometer is installed in the outlet section C, and when an abnormality (extreme temperature rise / fall) is detected in the temperature of the recovered liquid 3c, a temperature fluctuation occurs when the recovered cleaning liquid 3c flows into the circulation tank 5. Therefore, the collected cleaning liquid 3c in the outlet section C may be discharged to the outside of the tank through the extraction pipe 21.

Cleaning liquid 3 stored in circulation tank 5
Is returned to the cleaning tank 2 again via the suction pipe, the circulation pump 26 and the discharge pipe 27, and is subjected to degreasing cleaning of the steel strip 1. In the cleaning step and the circulation of the recovered cleaning liquid in the cleaning tank 2, the cleaning liquid adheres to the steel strip and is carried away, or a part of the cleaning liquid is lost due to evaporation or the like.
A replenishing tank 28 for the cleaning liquid is provided to replenish the loss. The cleaning liquid is supplied from the supply tank 28 to the pipe 29.
Through the circulation tank 5. Instead of the replenishing tank 28 for the cleaning liquid, a tank for the undiluted liquid for the cleaning liquid and a tank for the water for dilution may be separately provided, and each tank may be individually replenished as needed.

(1) Method of directly returning the cleaning liquid generated by foam breakage to the circulation tank, and returning from the circulation tank to the wash tank: a method using a conventional apparatus (a method using an apparatus disclosed in JP-A-11-36090) and (2) a method using foam breakage Of the cleaning liquid produced by the above-mentioned process, after removing impurities in the impurity separation tank, and then returning the cleaning liquid to the cleaning tank via the circulation tank. The cleanliness (change in alkali concentration, oil content, soap content and iron content) was compared and investigated. Table 1 shows the results.

[0038]

[Table 1]

Table 1 shows that, in the method using the conventional apparatus, the oil, soap and iron in the recovered liquid greatly increased and dirt was conspicuous. On the other hand, in the method using the apparatus of the present invention, the oil content slightly increased. Other than that, the cleanliness is the same as that of a new cleaning solution.

According to the apparatus of the present invention, it is possible to reduce the amount of the new cleaning liquid to be supplied to the circulation tank and to reduce the purchase cost of the cleaning agent. In addition, it was possible to prevent bubbles from overflowing from the circulation tank, and the working environment was improved.

FIG. 2 is a schematic view showing another embodiment of the cleaning equipment of the present invention.

FIG. 2 shows a cleaning tank for cleaning a metal material having grease or the like adhered to its surface, a circulation tank for circulating the cleaning liquid between the cleaning tank, and suction of bubbles of the cleaning liquid in the cleaning tank. Foam sucking means for performing foaming, foam sucked by the foam sucking means is supplied, a defoaming box in which foaming is performed, and a liquid generated by foam breaking in the defoaming box is supplied. An impurity separation tank for separating and removing impurity components,
And a piping system for supplying a liquid from which the impurity component has been separated and removed in the impurity separation tank to the circulation tank.

In the embodiment of FIG. 2, the steel strip 1 is degreased and washed in the washing tank 2, and a liquid layer of the washing liquid mixed with the bubbles 30 is formed in the upper layer of the washing liquid 3. In this method, suction is directly performed from the cleaning tank 2 without passing through the cleaning tank 5. For this reason, the foam suction port 9 of the foam suction means is provided in the cleaning tank 2. Other configurations that are completely the same as the embodiment of FIG. 1 can use a steam ejector, an air ejector, and the like. When using a steam ejector, the pressure set value of the steam ejector is set to 3 to 4 kg / cm ² is preferable.

In FIG. 2, the impurity separation tank 15
Has a plurality of separation sections divided by a plurality of partition plates 16 and a plurality of weirs 17, and the foam suction port 9 installed in the cleaning tank 2 follows the liquid level of the cleaning liquid in the cleaning tank. Up and down, the impurity separation tank 15 has at least 15 times the residence time of the defoaming liquid in the separation section.
And that the impurity separation tank 15 has a discharge means for discharging the impurities separated in each of the separation sections to the outside of the tank in each of the separation sections. This is similar to the first embodiment.

[0045]

EXAMPLE The method of the present invention was applied to the cleaning equipment of a continuous annealing apparatus using the apparatus shown in FIG. Here, a steam ejector was used as the ejector. In the cleaning equipment, caustic soda was used as a main component of the cleaning liquid, and various conditions of the cleaning liquid were set as follows. Alkaline concentration in the circulating tank (concentration of cleaning effective component): 1.8 (%), alkali temperature in the circulating tank: 70 (° C.), total volume of the circulating tank: 30 (m ³ ), volume of alkaline liquid in the circulating tank : 15 (m ^3).

After the periodic repair, the operation was started from the state of the fresh liquid. After 2 to 3 days without using the defoaming liquid circulation device, bubbles were constantly generated on the circulation tank and flowed out of the circulation tank.

Next, as the operating conditions of the defoaming liquid circulation device, the steam ejector pressure was set to 2.5 kg / cm ² , 3 kg
The cleaning equipment was operated at three levels of / cm ² and 4 kg / cm ² to collect bubbles, and the amount of the collected cleaning liquid, the properties of the collected cleaning liquid, the amount of steam used, and the like were investigated.

Table 2 shows the results of operating the cleaning equipment.

[0049]

[Table 2]

In Table 2, at 2.5 kg / cm ² , the amount of the collected washing liquid was small and the temperature was low. The foam recovery rate is 100
%, But bubbles overflowed out of the circulation tank. 4kg / c
With m ² , bubbles do not overflow from the circulation tank, but the alkali concentration of the recovered cleaning solution tends to decrease and the temperature is too high. In this embodiment, the pump for sending the recovered cleaning liquid from the impurity separation tank to the circulation tank has a heat-resistant temperature of 90 ° C. Further, since the amount of recovery is too large, the liquid level fluctuation in the first layer of the impurity separation tank is severe.

[0051] than its Results Table 2, when the main component is used a cleaning solution is sodium hydroxide, the pressure setting of the steam ejector is preferably ^{3kg / cm 2 ~4kg / cm 2} .
However, the most preferable condition is that the steam ejector pressure is set at 4 kg / cm ² from the amount of the collected washing liquid. However, in consideration of the collected washing liquid temperature and the concentration of the collected washing liquid, the optimum setting is 3 kg / cm ^{2 of the} steam ejector pressure. .

Next, the cleaning solution 3a containing impurities coming out of the defoaming box 11 of FIG. 1 was sampled from the tube 14, the sample solution was allowed to stand in a measuring cylinder, and the state of liquid separation was visually observed in time series. As a result, it was found that it took about 15 minutes or more for the sample liquid to separate into an oil component and a soap component in the upper layer, a washing liquid in the intermediate layer, and an iron component in the lower layer. From this experimental result, it is desirable to have an effective volume of the impurity separation tank so that the residence time of the defoaming liquid in the separation section is at least 15 minutes or more.

[0053]

According to the apparatus of the present invention, impurities are removed by passing an antifoaming liquid containing impurities obtained by defoaming bubbles through an impurity separation tank, and the obtained liquid is used as a recovery cleaning liquid in a circulation tank. , It is possible to maintain the cleaning ability of the recovered cleaning liquid for a long period of time. As a result, the replenishing amount of the cleaning liquid is reduced, so that the purchase cost of the cleaning agent can be reduced.
Further, efficient defoaming (foaming) can be realized by the combination of the steam ejector and the defoaming box. Further, the working environment around the circulation tank can be improved by realizing efficient defoaming.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one embodiment of a metal material cleaning facility of the present invention.

FIG. 2 is a schematic view showing another embodiment of the metal material cleaning equipment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steel strip 2 Cleaning tank 3 Cleaning liquid 3a Cleaning liquid (or defoaming liquid) containing impurities 3b Cleaning liquid in the section on the entrance side of the impurity separation tank 3c Recovery cleaning liquid 5 Circulation tank 6 Partition wall 7 First section of circulation tank 8 Circulation tank 2 section 9 Bubble suction port 10 Ejector 11 Defoaming box 12 Collision plate 13 Partition wall 15 Impurity separation tank 16 Partition plate 17 Weir (overflow) 23 Recovered liquid circulation pump 26 Circulation pump 28 Supply tank 30 Bubble

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Suga Politics 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Kiyofumi Shibuya 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Sun (72) Inventor Akihiro Nagahiro 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Japan Nihon Kokan Co., Ltd. (72) Inventor Seiji Sato 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Japan Inside the corporation

Claims (8)

[Claims] 1. A cleaning tank for cleaning a metal material having grease or the like adhering to the surface, a circulation tank for circulating a cleaning liquid between the cleaning tank, and suction of bubbles of the cleaning liquid in the circulation tank. Foam sucking means for performing foaming, a foam sucked by the foam sucking means is supplied, and a defoaming box in which foam is broken; and a liquid generated by foam breaking in the defoaming box is supplied. An impurity separation tank for separating and removing impurity components of
A pipe system for supplying a liquid from which the impurity component has been separated and removed in the impurity separation tank to the circulation tank. 2. The circulation tank has a partition wall whose lower part is immersed in the cleaning liquid stored in the tank, and one of the sections divided by the partition wall receives the cleaning liquid from the cleaning tank. The cleaning equipment for a metal material according to claim 1, wherein: 3. The metal according to claim 1, wherein the impurity separation tank has a plurality of separation sections divided by a plurality of partition plates and a plurality of weirs vertically provided from an upper portion of the tank. Material cleaning equipment. 4. The metal material according to claim 1, wherein the foam suction port of the foam suction means moves up and down in accordance with the level of the cleaning liquid in the circulation tank. Cleaning equipment. 5. An impurity separation tank having a separation section,
5. The metal material cleaning equipment according to claim 3, having an effective volume such that the residence time of the liquid in the separation section is at least 15 minutes or more. 6. An impurity separation tank having a separation section,
The metal material cleaning equipment according to any one of claims 3 to 5, further comprising a discharge unit configured to discharge impurities separated in each of the separation sections to the outside of the tank for each of the separation sections. 7. The cleaning equipment for a metal material according to claim 1, wherein a steam ejector is used as the foam suction means. 8. A cleaning tank for cleaning a metal material having oil or the like adhered to a surface thereof, a circulation tank for circulating a cleaning liquid between the cleaning tank, and suction of bubbles of the cleaning liquid in the cleaning tank. Foam sucking means for performing foaming, a foam sucked by the foam sucking means is supplied, and a defoaming box in which foam is broken; and a liquid generated by foam breaking in the defoaming box is supplied. An impurity separation tank for separating and removing impurity components of
A pipe system for supplying a liquid from which the impurity component has been separated and removed in the impurity separation tank to the circulation tank.