JP2022020125A - Aluminum seamless can washing method and washing device - Google Patents

Abstract

To provide an aluminum seamless can washing method and washing device that achieve reduction in environmental load and employ a wastewater treatment process capable of reusing treated wastewater.SOLUTION: A washing method for an aluminum seamless can be molded by drawing and ironing, includes at least a degreasing step for degreasing the aluminum seamless can with a degreasing agent; a water-washing step for using water to wash the degreased aluminum seamless can; and a wastewater treatment step for using a membrane separation activated sludge treatment to treat wastewater from the degreasing step and the water-washing step, where the amount of aluminum in the wastewater supplied for the wastewater treatment step is 5-200 mg/L.SELECTED DRAWING: Figure 1

Description

The present invention relates to a cleaning method and a cleaning device for an aluminum seamless can, and more particularly to a cleaning method and a cleaning device for an aluminum seamless can provided with a cleaning wastewater treatment method capable of reducing the burden on the environment. ..

Conventionally, aluminum seamless cans (hereinafter, may be simply referred to as "aluminum seamless cans" or "seamless cans") have been widely used as containers for foods and drinks such as beer and carbonated drinks. Since such a seamless can is obtained by subjecting an aluminum plate to harsh processing such as squeezing and ironing, it is generally molded using a lubricant and a coolant. As a result, the lubricant and the smut are attached to the seamless can after the drawing and ironing process. Further, a film of aluminum oxide is formed on the surface of the aluminum plate.
It is necessary to remove the adhered lubricant or the like on the can on which the lubricant or the like adheres and the aluminum oxide film is formed before being applied to the painting / printing process. Further, in order to form a good chemical conversion coating on the aluminum surface, it is necessary to degreasing with a degreasing agent containing a surfactant and an etching agent, and to wash the degreasing agent with water.

The conventional cleaning step of an aluminum seamless can generally includes a degreasing step using a degreasing agent for removing a lubricant and the like, a water washing step for removing the degreasing agent, and further, if necessary, a surface. It has a surface treatment step using a treatment liquid and a water washing step for removing the surface treatment liquid (Patent Documents 1 to 3, etc.).
The cleaning wastewater discharged from such a cleaning step contains a lubricant and a degreasing agent used when molding an aluminum seamless can, a fluoride in a surface treatment liquid, a phosphoric acid compound, aluminum, and the like. Conventionally, a wastewater treatment method has been used in which the washing wastewater is coagulated and settled or pressure-floated by adding a chemical such as a coagulant, and the wastewater is separated and treated.

Japanese Patent No. 2587916 Japanese Patent No. 3451187 Japanese Unexamined Patent Publication No. 2002-346672

However, the above-mentioned wastewater treatment method requires a large amount of chemicals and water, and in order to treat a large amount of wastewater, the wastewater treatment equipment must be enlarged, and a vast land for installing the equipment is required. There is a problem in terms of economic efficiency. In addition, there is also a problem that the environmental load is large because the entire amount of the treated wastewater is discharged to sewage or the like.
A membrane-separated activated sludge method that treats sewage using microorganisms is also known as a treatment method for factory effluent, but the cleaning effluent of aluminum seamless cans contains a large amount of the above-mentioned lubricant and the like. Therefore, the biochemical oxygen demand (BOD) and the chemical oxygen demand (CODcr) are large, and it is difficult to apply the membrane separation activated sludge method as it is.

Therefore, an object of the present invention is to provide a cleaning method and a cleaning device capable of efficiently performing wastewater treatment by the membrane separation active sludge method in the cleaning method of an aluminum seamless can.
Another object of the present invention is to provide a cleaning method and a cleaning device for an aluminum seamless can, which does not require a large area of land and has a wastewater treatment method in which the treated wastewater can be reused.

According to the present invention, in a method for cleaning an aluminum seamless can formed by squeezing and ironing, a degreasing step of degreasing the aluminum seamless can with a degreasing agent and a water washing of the degreased aluminum seamless can with water. It has at least a wastewater treatment step of treating the wastewater from the step and the degreasing step and the washing step by the film separation active sludge method, and the amount of aluminum in the wastewater supplied to the wastewater treatment step is 5 to 200 mg / L. A method for cleaning a seamless aluminum can is provided.

In the method for cleaning an aluminum seamless can of the present invention,
1. 1. The BOD of the wastewater supplied to the wastewater treatment step is 300 mg / L or less and the CODcr is 700 mg / L or less.
2. 2. The TOC of the wastewater supplied to the wastewater treatment step is 500 mg / L or less.
3. 3. The degreasing agent contains a surfactant and at least one of sulfuric acid, sodium hydroxide, and potassium hydroxide.
4. After the degreasing treatment step, there is a surface treatment step using a surface treatment liquid containing a phosphoric acid compound and / or a fluoride, and a neutralization treatment step for neutralizing the wastewater supplied to the wastewater treatment step. To have more,
5. The amount of fluoride ions in the wastewater supplied to the neutralization treatment step is 40 mg / L or less.
6. Having a further pre-cleaning step prior to the degreasing step,
7. The washing water in the pre-cleaning step is not heated,
8. It further has a filtration treatment step of filtering the treated water obtained by the wastewater treatment step by reverse osmosis membrane filtration, and the filtrate obtained by the filtration treatment step is washed with the water washing step and / or the preliminary washing step. Reusing as water,
9. Reusing the filtrate to a proportion of 30-95% of the wash water used in the wash step and / or the pre-wash step.
10. The squeezing and ironing molding is a squeezing and ironing molding that does not use a lubricant.
Is preferable.

According to the present invention, in a cleaning device for cleaning an aluminum seamless can formed by squeezing and ironing, a pre-cleaning means for an aluminum seamless can supplied from a molding means, which is supplied from the pre-cleaning means. Degreasing means for degreasing aluminum seamless cans with a degreasing agent, water washing means for washing aluminum seamless cans supplied from the degreasing means, drying means for drying aluminum seamless cans supplied from the water washing means, The pre-cleaning means, the degreasing means, the wastewater treatment means for treating the wastewater discharged from the water-washing means by the film-separating active sludge method, and at least the transport for continuously transporting the aluminum seamless can from the molding means to the drying means. An aluminum seamless can cleaning device is provided that comprises at least means.

In the aluminum seamless can cleaning device of the present invention,
1. 1. A surface treatment means using a surface treatment liquid containing a phosphoric acid compound and / or a fluoride is provided on the downstream side of the degreasing means, and a neutralization treatment means for neutralizing the wastewater supplied to the wastewater treatment means. To have more,
2. 2. Having a filtering means for reverse osmosis membrane filtering of the treated liquid obtained by the wastewater treatment means, and a circulating means for supplying the filtered liquid obtained by the filtering means to the water washing means and / or the preliminary cleaning means.
Is preferable.

In the method for cleaning an aluminum seamless can of the present invention, efficient wastewater treatment is possible by the membrane separation active sludge method, so that the conventional wastewater treatment equipment that requires a vast land can be miniaturized and treated. The later wastewater can be reused as washing water after being treated with a reverse osmosis membrane, which is excellent in economic efficiency. In addition, since the amount of sludge and the amount of wastewater discharged into sewage are small, there is an advantage that the burden on the environment can be reduced.

It is a chart diagram which shows the preferable flow of the cleaning process of the aluminum seamless can of this invention. It is a figure in order to explain an example of wastewater treatment by a membrane separation activated sludge method. It is a side view schematically showing an example of the cleaning apparatus of this invention.

In the method for cleaning an aluminum seamless can of the present invention, it is one of the important features to use the membrane separation active sludge method (MBR method) for wastewater treatment, and the amount of aluminum in the wastewater supplied to the wastewater treatment process is one of the important features. Another important feature is that it is 5 to 200 mg / L.
The MBR method adopted as a method of wastewater treatment in the present invention decomposes organic substances such as lubricants contained in washing wastewater by microorganisms, and the microorganisms are decomposed into MF membranes (microfiltration membranes) and UF membranes (ultrafiltration membranes). It is a method of filtering using By reusing it as water, it is possible to reduce the amount of water supplied for new use in the cleaning process of aluminum seamless cans, and it is also possible to reduce the amount of wastewater discharged to sewage, etc., which has a burden on the environment. Can be reduced.
In the present invention, the amount of aluminum is a value measured by ICP emission spectroscopic analysis in the factory wastewater test method of JIS K 102.

In the cleaning method of the present invention, the amount of aluminum in the cleaning wastewater is in the range of 5 to 200 mg / L, particularly 5 to 100 mg / L, so that the oil content and the like in the cleaning wastewater after neutralization are aggregates with the aluminum. By forming and separating the wastewater, the wastewater is efficiently cleaned. Further, when surface treatment is performed, fluoride ions, phosphate ions and the like can be efficiently removed due to the presence of aluminum. In addition, it is possible to reduce the amount of fluoride ions that affect microorganisms and efficiently perform wastewater treatment by the MBR method. If the amount of aluminum is less than the above range, the above-mentioned effect of aluminum may not be sufficiently performed, while if the amount of aluminum is larger than the above range, the amount of precipitated aluminum after neutralization is excessive. On the contrary, the filtration efficiency by the MBR method may be lowered.

In the present invention, the washing wastewater supplied to the treatment step by the MBR method has an aluminum amount in the above range, a biochemical oxygen demand (BOD) of 300 mg / L or less, and a chemical oxygen consumption (CODcr). It is preferable that the amount is 700 mg / g or less and the total organic carbon amount (TOC) is 500 mg / L or less, which enables efficient treatment by the MBR method.
BOD is the amount of oxygen (mg / L) consumed by aerobic microorganisms in the presence of dissolved oxygen at 20 ° C for 5 days, and CODcr is a reaction at 100 ° C for 30 minutes with potassium dichromate added as an oxidizing agent. It is the amount of potassium dichromate consumed when it is made to be converted into oxygen (mg / L), and these are indicators showing the degree of water pollution by organic substances. The TOC is a water quality index that expresses the total amount of organic substances existing in water by the amount of carbon (mg / L) contained in the organic substances, and is a water quality index that expresses the organic substances that can be oxidized by the amount of carbon. By controlling the BOD, CODcr and TOC of the washing wastewater supplied to the treatment process by the MBR method to the above values or less, the amount of aluminum is in the above range, and the wastewater by the MBR method is more efficiently discharged. Processing becomes possible.

(Aluminum seamless can)
In the cleaning method of the present invention, the aluminum seamless can to be cleaned is not particularly limited in its molding method and the like, and a conventionally known aluminum seamless can can be targeted, but it is supplied to the wastewater treatment step by the MBR method. From the viewpoint of keeping the BOD, COD and TOC of the washing wastewater to or less than the above-mentioned values, it is preferable to use an aluminum seamless can in which the amount of lubricant used at the time of molding is reduced.
Aluminum seamless cans are generally made by drawing an aluminum plate made of a well-known aluminum or aluminum alloy such as 3004 material or 3104 material, if necessary, using a conventionally known lubricant such as mineral oil or synthetic oil and water. It is molded by harsh processing such as drawing / deep drawing, drawing / ironing, drawing / bending / stretching / ironing.
As the aluminum seamless can with the reduced amount of adhesive lubricant as described above, the aluminum seamless can formed by squeezing and ironing by dry molding without using a lubricant, or the wet molding using a lubricant. Even so, examples thereof include aluminum seamless cans formed by using a water-soluble lubricant or reducing the amount of the lubricant used.
In addition to the above-mentioned lubricant, aluminum seamless cans also have smut generated during molding. A film of aluminum oxide is formed on the surface of the aluminum plate.

(Washing process)
FIG. 1 is a diagram showing an example of a method for cleaning an aluminum seamless can of the present invention. For a seamless can formed in a can manufacturing process, a pre-cleaning step, a degreasing step, a first water washing step, a surface treatment step, and a second. After a water washing process, it is continuously transported to a drying process. Further, the washing wastewater discharged from each step is subjected to a neutralization treatment step and a treatment step by MBR, and the filtered water is purified to a level that can be reused as washing water through the RO membrane. In the specific example shown in the figure, the cleaning step includes a pre-cleaning step, a surface treatment step and a second water washing step, and the wastewater treatment step includes a rough filtration step, a neutralization treatment step and a filtration step using a back-penetrating film. Although included, these steps are not essential and may be added as needed, as described below. Further, in the present specification, the preliminary cleaning step to the second water washing step are roughly referred to as a washing step, and the three steps of a rough filtration step, a neutralization treatment step, and a wastewater treatment step by the MBR method are roughly referred to as wastewater. It is a processing process.
As the washing water used in the washing step, industrial water, distilled water, pure water (deionized water) and the like can be used, but in the present invention, the treated water (filtered water) that has undergone the wastewater treatment step is used. It is excellent in water saving because it can be reused and 30 to 95% of the total washing water used in the preliminary washing step and the washing step can be replaced with the treated water.

[Preliminary cleaning process]
The pre-cleaning step is a step for removing impurities adhering to the can in the can manufacturing step before the subsequent degreasing treatment, and can be omitted depending on the state of the aluminum seamless can after molding.
Further, in the pre-cleaning step, washing water whose temperature is generally adjusted to 50 to 75 ° C. using a heating device is used, but in the present invention, as described above, the amount of lubricant used in the can-making step. Therefore, the washing water used in the preliminary washing step can exhibit sufficient washing ability without a special heating device.

[Degreasing process / first washing process]
The aluminum seamless cans that have been pre-cleaned as necessary in the pre-cleaning step described above are continuously carried into the degreasing step of the cleaning device at high speed with the can bottom facing up.
In the degreasing step, the degreasing agent is sprayed from above and below onto the aluminum seamless can to remove the lubricant and smut adhering to the surface of the aluminum seamless can and to remove the aluminum oxide film formed on the surface of the aluminum can.
As the degreasing agent, a conventionally known degreasing agent can be used. For example, a surfactant and an acid cleaning solution or an alkaline cleaning solution containing an acid or an alkali can be used, but a surfactant is preferable. , It is preferable to use a degreasing agent containing one of sulfuric acid, sodium hydroxide and potassium hydroxide. As the surfactant, any of a cationic surfactant, an anionic surfactant, a nonionic surfactant, and an ionic surfactant can be used without limitation, but it is particularly preferable to use a nonionic surfactant. ..
In the present invention, as described above, it is preferable that BOD, CODcr and TOC in the washing wastewater are reduced. Therefore, in the can manufacturing process, dry molding without using a lubricant or the amount of the lubricant used is used. Measures such as reduction of the amount of water are taken. Therefore, a degreasing agent having a reduced content of a surfactant, an acid or an alkaline component, etc. can be used, and the degreasing agent component in the wastewater discharged from the degreasing treatment step can be reduced. Further, by adjusting the type and amount of the degreasing agent used, the amount of aluminum degreased from the seamless can by the degreasing treatment can be adjusted. The amount of aluminum in the wastewater supplied to the wastewater treatment step is maintained in a suitable range by adjusting the amount of aluminum degreased by the degreasing treatment and the amount of water used in the subsequent cleaning steps.

The aluminum seamless can subjected to the degreasing treatment is washed with water in the first washing step and then transported to the surface treatment step. In the specific example shown in FIG. 2, the first cleaning step is performed in one step, but it can also be performed in two steps in which a pure water rinsing step is further provided after the first water washing step, and the process is appropriately changed. be able to.
The washing wastewater discharged from the degreasing step and the first water washing step contains organic substances derived from the lubricant removed by the degreasing treatment, but in the present invention, it is finally supplied to the wastewater treatment step. It is desirable that the BOD in the wastewater is 300 mg / L or less, the CODcr is 700 mg / g or less, and the TOC is 500 mg / L or less.

[Surface treatment process / second cleaning process]
The surface treatment step may be performed by chemical conversion treatment using a conventionally known surface treatment agent such as zirconium-based, titanium-based, or chromium-based, in order to improve the coating film stability and corrosion resistance of the aluminum seamless can after degreasing. can. The surface treatment process itself is not an indispensable process, and for example, in the case of a resin-coated aluminum seamless can molded using a resin-coated aluminum plate, or in the case of substituting by another method such as conditioning with phosphate. No surface treatment step is required.
As the surface treatment agent, conventionally known ones can be used, and the surface treatment agent is not limited to this, but is not limited to phosphoric acid compounds such as zirconium phosphate, sodium phosphate and phosphoric acid, and aluminum fluoride, zirconium fluoride, phosphoric acid and the like. A surface treatment agent containing fluoride can be preferably used.
In the present invention, as described above, 5 to 200 mg / L of aluminum is contained in the washing wastewater supplied to the wastewater treatment step, and the phosphoric acid compound and fluoride in the washing wastewater react with aluminum and precipitate. Therefore, it is possible to promote the separation of phosphoric acid compounds and fluorides in the washing wastewater.
The wastewater discharged from the surface treatment step has an amount of fluoride ions in the wastewater of less than 40 mg / L at the stage where the wastewater from the first cleaning step described above is mixed and supplied to the wastewater treatment step. It is desirable to have. When the amount of fluoride ions is larger than the above value, it becomes difficult to sufficiently reduce the amount of fluoride ions in the neutralization treatment step described later, which affects the microorganisms used in the wastewater treatment step by the MBR method. There is a risk.
The aluminum seamless can that has undergone the surface treatment step is transported to the drying step through the second cleaning step.

[Drying process]
The surface-treated aluminum seamless cans carried into the drying process are heated and dried in a dryer such as an oven. The aluminum can that has undergone the surface treatment step is dried at a temperature of 170 to 210 ° C. for 60 to 100 seconds, and then transferred to the subsequent painting / printing step.

(Wastewater treatment process)
As shown in FIG. 1, the washing wastewater discharged from the above-mentioned preliminary washing step, degreasing step, first water washing step, surface treatment step, and second water washing step is drainage by the rough filtration step, the neutralization treatment step, and the MBR method. It is attached to the treatment process and filtration process, and the filtered water can be reused as washing water.
The rough filtration step is not essential depending on the state of the washing wastewater and can be omitted. Further, the neutralization treatment step can be omitted if the above-mentioned surface treatment step is omitted. Further, the filtration step using a reverse osmosis membrane is also an arbitrary step.

[Neutralization process]
In the neutralization treatment step, phosphate ions, fluoride ions, etc. in the surface treatment agent discharged from the surface treatment step are insolubilized by neutralization, and then the MF membrane or UF membrane in the wastewater treatment step by the MBR method is performed. It can be easily filtered.
The neutralization treatment itself can be carried out by a conventionally known method, but as described above, the washing wastewater of the present invention contains aluminum in an amount of 5 to 200 mg / L, preferably 5 to 100 mg / L. By neutralization, aluminum plays the role of an inorganic flocculant, becomes the core of oil agglomeration, and reacts with phosphate ions, fluoride ions, and the like. That is, the phosphate ion becomes aluminum phosphate and becomes insolubilized and aggregates, and the fluoride ion becomes aluminum fluoride and becomes insoluble and aggregates. In addition, sulfate ions in the degreasing agent also become aluminum sulfate, which can be insolubilized and aggregated.
Further, as described above, the amount of fluoride ions in the washing wastewater discharged from the surface treatment step is controlled to be less than 40 mg / L at the stage of being supplied to the wastewater treatment step. As a result, the amount of fluoride ions in the treated water can be reduced to less than 20 mg / L by the neutralization treatment step, and the influence on microorganisms in the subsequent wastewater treatment step is also reduced.

[Wastewater treatment process by MBR method]
The washed wastewater that has undergone the neutralization treatment step is separated from sludge and treated water by a membrane separation activated sludge method (MBR method) using an MF membrane or a UF membrane. The treatment itself by the MBR method used in the present invention can be performed by a conventionally known method.
FIG. 2 is a diagram for schematically explaining an example of membrane separation activated sludge treatment. The membrane separation activated sludge tank is installed in a state where a membrane unit 2 provided with a plurality of membrane modules 2a and a water collecting pipe 2b is immersed in the aeration tank 1, and a bubble air diffuser means 3 is installed below the membrane unit 2. Is installed, and the air supplied from the blower 4 is aerated toward the MF membrane constituting the membrane unit 2. The bubbles, together with the washing of the MF membrane, cause circulation in the tank to promote mixing and stirring of the activated sludge and the water to be treated. Further, when the oxygen in the bubbles comes into contact with the liquid to be treated, it dissolves in the liquid to be treated as dissolved oxygen. The aeration tank 1 is provided with a supply means 5 for quantitatively supplying wastewater (water to be treated) from the neutralization treatment step which is the previous step, and a drainage means equipped with a suction pump for discharging the treated water to the outside of the tank. 6. A discharge means 7 equipped with a suction pump for discharging sludge to the outside of the tank is provided.

Examples of the membrane cartridge constituting the membrane unit installed in the membrane separation activated sludge tank include an MF membrane or a UF membrane, but it is preferable to use a 0.2 to 0.5 μm MF membrane. Further, although it depends on the amount of water to be treated, in a general wastewater treatment device for an aluminum seamless can, the tank preferably has a volume of 300 to 600 m ³ , and the size of the device can be reduced.
The amount of suspended solids (MLSS) in the tank is preferably in the range of 5000 to 10000 mg / L.
The wastewater (water to be treated) supplied to the wastewater treatment step by the MBR method has a fluoride ion content of less than 20 mg / L, particularly less than 15 mg / L, due to the neutralization treatment step. There is no effect on.
The wastewater (water to be treated) supplied to the wastewater treatment process is efficiently reduced by the MBR method because the BOD is reduced to 300 mg / L or less, the CODcr is reduced to 700 mg / L or less, and the TOC is reduced to 500 mg / L or less. It is possible to process.

[Filtration process]
The treated water discharged from the wastewater treatment step by the MBR method is sufficiently cleaned, but when it is reused as washing water, it may be further subjected to a filtration step using a reverse osmosis membrane. Suitable.
The filtration step itself using the reverse osmosis membrane can be performed by a conventionally known method, and the pressure difference (filtration pressure) and the like can be appropriately adjusted according to the reverse osmosis membrane to be used.
The filtered water obtained by filtration using a reverse osmosis membrane can be suitably reused as washing water because impurities such as sodium ions are also removed, and the washing water used in the washing step is 30 to 90. Can be used in% amount.

(Washing equipment)
As shown in FIG. 3 to be described later, the cleaning device for cleaning the aluminum seamless can of the present invention is, roughly speaking, a cleaning device A in a narrow sense that performs from cleaning to drying of the aluminum seamless can, and a cleaning device from this cleaning device. It consists of a wastewater treatment device B for treating wastewater.
The cleaning device A in a narrow sense includes a pre-cleaning means for an aluminum seamless can supplied from a molding means for an aluminum seamless can, a degreasing means for degreasing an aluminum seamless can supplied from the pre-cleaning means with a degreasing agent, and the degreasing means. A water washing means for washing aluminum seamless cans supplied from, a drying means for drying aluminum seamless cans supplied from the water washing means, and a transporting means for continuously transporting aluminum seamless cans from at least a molding means to a drying means. And have.
As described above, in the cleaning of the aluminum seamless can, since the surface treatment can be performed after the degreasing treatment, a surface treatment means using the above-mentioned surface treatment liquid can be provided on the downstream side of the degreasing means, if necessary.

The wastewater treatment device B includes at least a pre-cleaning means, a degreasing means, and a wastewater treatment means for treating the wastewater discharged from the water-washing means by the MBR method.
Further, the treatment apparatus is provided with a neutralization treatment means for neutralizing the pH of the wastewater supplied to the wastewater treatment means and neutralizing fluoride ions and the like in the wastewater.
Furthermore, when the treated water treated by the wastewater treatment device is reused as the washing water of the washing device, the wastewater treatment device is used. A filtration means for filtering the treatment liquid obtained by the wastewater treatment means by a reverse osmosis membrane, and a circulation means for supplying the filtrate obtained by the filtration means to the water washing means and / or the preliminary cleaning means are provided as necessary. Has been done.

FIG. 3 is a side view schematically showing an example of the cleaning device of the present invention, in which the aluminum seamless can 10 to which the lubricant or the like carried in from the molding device is attached is continuously reached by the transport means 11 to the drying means 17. Is transported. As the transporting means, a conventionally known transporting means such as a mesh conveyor or a net conveyor can be used, and the width direction of the transporting means (direction perpendicular to the traveling direction) so that the opening of the aluminum seamless can is downward. ) Are placed side by side and continuously transported.
As is clear from FIG. 3, in a preferred embodiment of the cleaning device of the present invention, the pre-cleaning means 12, the degreasing means 13, from the upstream side (left side in FIG. 3) to the downstream side (right side in FIG. 3) of the cleaning device. The first water washing means 14, the surface treatment means 15, the second water washing means 16, and the drying means 17 are installed along the transport means 11.
A degreasing agent, a washing water, pure water, a surface treatment agent, and a washing water are applied to each of the preliminary cleaning means 12, the degreasing means 13, the first water washing means 14, the surface treatment means 15, and the second water washing means 16, respectively. A spraying device 20, 20, 20 ... With a plurality of discharge ports capable of spraying from the vertical direction of an aluminum seamless can is installed, and drainage pipes 21 and 21 for introducing cleaning wastewater into a wastewater treatment process. , 21 ... are installed.

The drainage pipes 21, 21, ... It is connected to the tank 22. From the drainage tank 22, the wastewater is quantitatively supplied to the neutralization treatment means 31. Although not shown, in the case where impurities are present in the washing wastewater, it is possible to pass through a coarse filtration means such as a metal filter before supplying the neutralization treatment means.
The neutralization treatment means 31 is provided with a stirring means 31b and a supply device 31c for supplying a neutralizing agent such as sodium hydroxide to the reaction tank 31a. In the wastewater supplied from the drainage tank 22 to the reaction tank 31a, the oil in the wastewater is separated by the aggregation effect of aluminum, and the phosphate compounds and fluorides contained in the second washing wastewater are aluminum phosphate and fluoride. Aluminum and the like are coagulated and settled and removed, and the amount of fluoride ions becomes less than 20 mg / L.
The wastewater from which the agglomerates have been removed by the neutralization treatment is supplied from the pipe 31d to the wastewater treatment means 32 by the MBR method, and the sludge that has aggregated and settled is discharged from the discharge pipe 31e.

The wastewater treatment means 32 by the MBR method is as shown in FIG. 2 described above, and includes a treatment tank 1 provided with a membrane unit 2, an air bubble diffuser means 3, and a blower 4. The treated water obtained through the water collecting pipe 2b is supplied to the filtration means 33 provided with the reverse osmosis membrane module, which is performed next, if necessary, via the drainage means 6.
The treated water that has passed through the filtration means by the reverse osmosis membrane is supplied to the preliminary cleaning means 11 and the water washing means 14 and 16 described above by the circulation means 35 including the water absorption pump 34.

The cleaning device of the present invention is not limited to the specific example shown in FIG. 3, and it is sufficient to install cleaning means of a required number or length (line length) before and after the degreasing means and the surface treatment means. In addition, the number of nozzles of the injection device and the number of blower devices can be changed as appropriate.

1 Membrane separation active sludge tank, 2 Membrane unit, 3 Bubble air diffuser means, 4 Blower, 5 Supply means, 6 Drainage means, 10 Aluminum seamless can, 11 Transport means, 12 Preliminary cleaning means, 13 Degreasing means, 14 First cleaning Means, 15 Surface treatment means, 16 Second cleaning means, 17 Drying means, 20 Spraying device, 21 Drainage pipe, 22 Drainage tank, 31 Neutralization treatment means, 32 MBR method wastewater treatment means, 33 Filtering means, 34 Treated water Tank, 35 circulation means.

Claims (14)

In the method of cleaning seamless aluminum cans formed by squeezing and ironing,
A degreasing step of degreasing the aluminum seamless can with a degreasing agent, a water washing step of washing the degreased aluminum seamless can with water, and wastewater for treating the wastewater from the degreasing step and the water washing step by a film separation active sludge treatment. Have at least a processing step,
A method for cleaning a seamless aluminum can, characterized in that the amount of aluminum in the wastewater supplied to the wastewater treatment step is 5 to 200 mg / L. The cleaning method according to claim 1, wherein the BOD of the wastewater supplied to the wastewater treatment step is 300 mg / L or less and the CODcr is 700 mg / L or less. The cleaning method according to claim 1 or 2, wherein the TOC of the wastewater supplied to the wastewater treatment step is 500 mg / L or less. The cleaning method according to any one of claims 1 to 3, wherein the degreasing agent contains a surfactant and at least one of sulfuric acid, sodium hydroxide, and potassium hydroxide. After the degreasing treatment step, there is a surface treatment step using a surface treatment liquid containing a phosphoric acid compound and / or a fluoride, and a neutralization treatment step for neutralizing the wastewater supplied to the wastewater treatment step. The cleaning method according to any one of claims 1 to 4. The cleaning method according to claim 5, wherein the amount of fluoride ions in the wastewater supplied to the neutralization treatment step is 40 mg / L or less. The cleaning method according to any one of claims 1 to 6, further comprising a pre-cleaning step before the degreasing step. The cleaning method according to claim 7, wherein the cleaning water in the preliminary cleaning step is not heated. It further has a filtration treatment step of filtering the treated water obtained by the wastewater treatment step by reverse osmosis membrane filtration, and the filtrate obtained by the filtration treatment step is used for washing the water washing step and / or the preliminary washing step. The cleaning method according to any one of claims 1 to 8, which is reused as water. The washing method according to claim 9, wherein the filtrate is reused so as to have a ratio of 30 to 95% of the washing water used in the water washing step and / or the preliminary washing step. The cleaning method according to any one of claims 1 to 10, wherein the drawing iron molding is a drawing iron molding that does not use a lubricant. In a cleaning device for cleaning aluminum seamless cans formed by squeezing, pre-cleaning means for aluminum seamless cans supplied from the molding means and aluminum seamless cans supplied from the pre-cleaning means are degreased. Degreasing means for degreasing using the degreasing means, water washing means for washing the aluminum seamless can supplied from the degreasing means, drying means for drying the aluminum seamless can supplied from the water washing means, pre-cleaning means and degreasing means. In addition, it has at least a wastewater treatment means for treating the wastewater discharged from the water washing means by a film-separating active sludge treatment, and at least a transporting means for continuously transporting an aluminum seamless can from the molding means to the drying means. A featured aluminum seamless can cleaning device. A surface treatment means using a surface treatment liquid containing a phosphoric acid compound and / or a fluorine compound is provided on the downstream side of the degreasing means, and a neutralization treatment means for neutralizing the wastewater supplied to the wastewater treatment means. 12. The cleaning device according to claim 12. Claimed to have a filtering means for reverse osmosis membrane filtering of the treated liquid obtained by the wastewater treatment means, and a circulation means for supplying the filtered liquid obtained by the filtering means to the water washing means and / or the preliminary cleaning means. The cleaning device according to 12 or 13.

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