KR102268168B1 - Degreasing agent and device for removing sludge in the same - Google Patents

Abstract

The degreasing agent of embodiments of the present invention includes an alkali agent, a surfactant including an anionic surfactant represented by Formula 1 and a nonionic surfactant represented by Formula 2, and a hydrotrope including sodium gluconate. The degreasing process is performed at room temperature using a degreasing agent, and degreasing properties and defoaming properties may be improved.

Description

DEGREASING AGENT AND DEVICE FOR REMOVING SLUDGE IN THE SAME

The present invention relates to a degreasing agent and a sludge removal device included therein. More specifically, it relates to a degreasing agent containing an alkali agent and a sludge removal device included therein.

On the manufactured cold-rolled steel sheet, rolling oil or anti-rust oil is present. The rolling oil or rust preventive oil remaining on the cold rolled steel sheet causes carbon precipitation or plating peeling during cold rolled steel sheet processing. Accordingly, the rolling oil or rust-preventing oil must be removed before the cold-rolled steel sheet enters an annealing process.

For example, the rolling oil or rust preventive oil ^{may be removed through a saponification reaction with hydroxide ions (OH −} ) contained in an alkali agent, and the saponification reaction may be performed at about 75 to 85° C. .

However, when the rolling oil or rust preventive oil is removed at a high temperature, a large amount of foam is generated from the degreasing agent, and an additional foam removal process must be performed. Accordingly, there is a need for a degreaser that removes the rolling oil or rust preventive oil at room temperature and minimizes the generation of bubbles.

For example, Korean Patent Application Laid-Open No. 2010-0069121 discloses an alkaline degreasing agent composition comprising sodium hydroxide and ethylenediaminetetraacetic acid (EDTA), but sufficient defoaming properties through ethylenediaminetetraacetic acid (EDTA) and it is difficult to implement degreasing properties.

Korean Patent Publication No. 2010-0069121

One object of the present invention is to provide a degreasing agent having improved defoaming properties and degreasing properties.

One object of the present invention is to provide a sludge removal device contained in the degreasing agent.

1. alkali agent; a surfactant comprising an anionic surfactant represented by the following formula (1) and a nonionic surfactant represented by the following formula (2); and a hydrotrope comprising sodium gluconate:

[Formula 1]

(Wherein, EO is an oxyethylene group, PO is an oxypropylene group, a and b are each an integer of 0 to 20, R ₁ is an alkyl group having 8 to 16 carbon atoms, and M ⁺ is a monovalent cation of an alkali metal)

[Formula 2]

(Wherein, EO is an oxyethylene group, PO is an oxypropylene group, m and n are each an integer from 1 to 19, m+n is an integer from 5 to 40, R ₂ and R ₃ are an alkyl group having 1 or more carbon atoms, , the _{sum of carbon atoms of R 2} and R ₃ is 5 to 18, and R ₄ is hydrogen or a methyl group).

2. The degreasing agent according to 1 above, comprising 5 to 55% by weight of the alkali agent, 0.01 to 30% by weight of the anionic surfactant, 0.01 to 30% by weight of the nonionic surfactant, and 0.2 to 35% by weight of the hydrotrope.

3. The degreasing agent according to 1 above, wherein the alkali agent includes at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium orthosilicate and sodium metasilicate.

4. The method of 1 above, wherein the anionic surfactant further comprises at least one selected from the group consisting of sodium dioctylsulfosuccinate, sodium alkyldiphenyloxidedisulfonate, sodium alkylbenzenesulfonate, and sodium fatty acid having 8 to 20 carbon atoms. , degreaser.

5. The degreasing agent according to the above 1, further comprising an auxiliary surfactant including a polyoxyethylene-based nonionic surfactant.

6. The degreasing agent according to the above 5, wherein the content of the auxiliary surfactant is 0.01 to 10% by weight.

7. The degreasing agent according to 5 above, wherein the polyoxyethylene-based nonionic surfactant comprises at least one selected from the group consisting of polyoxyethylene lauryl ether, polyoxyethylene decyl ether and laureth methyl ether.

8. The above 1, wherein the hydrotrope is ethylene glycol, propylene glycol, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethanolamine, 1,2-benzylisotriazole, sodium naphthalenesulfonate, xylenesulfonic acid A degreasing agent further comprising at least one selected from the group consisting of sodium and polyoxyethylene ester-based phosphates.

9. The degreasing agent according to the above 1, wherein the content of sodium gluconate is 70% by weight or more based on the total weight of the hydrotrope.

10. The degreasing agent according to the above 1, further comprising a metal remover and an antifoaming agent.

11. In the above 10, the content of the metal remover is 0.01 to 5% by weight, the content of the defoaming body is 0.01 to 5% by weight, the degreasing agent.

12. The above 10, wherein the metal removing agent is ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), sodium citrate, ethylenediamine, methylphosphonic acid And a degreasing agent comprising at least one selected from the group consisting of diphosphonic acid.

13. The degreasing agent according to the above 10, wherein the antifoaming agent comprises a silicone-based antifoaming agent or a fatty acid-based antifoaming agent.

14. A sludge removal device comprising a settling tank in which the degreasing agent of 1 above is injected, and at least one magnet is disposed on a side or lower surface, wherein 1 to 15 of the settling tanks are continuously arranged in a horizontal direction.

15. The sludge removal device according to the above 14, wherein the side heights of the settling tanks are gradually lowered according to the moving direction of the degreasing agent.

16. The sludge removal device according to the above 14, wherein the volume of the settling tanks gradually decreases according to the moving direction of the degreasing agent.

17. A sludge removal device comprising a settling tank in which the degreasing agent of 1 above is injected and at least one magnet is disposed on a lower surface, wherein 1 to 15 of the settling tanks are continuously arranged in a vertical direction.

18. 1 to 15 settling tanks in which the degreasing agent of the above 1 is injected are continuously arranged in a vertical or horizontal direction, disposed on the outer wall of the settling tank, and comprising at least one detachable magnet.

The degreasing agent according to embodiments of the present invention includes a surfactant including a copolymer structure including an oxyethylene group and an oxypropylene group as a repeating unit, and a hydrotrope including sodium gluconate, and has excellent defoaming properties and degreasing properties Do.

The degreasing agent contains an alkali agent, the surfactant, and the hydrotrope in a specific amount, effectively preventing a large amount of bubbles from being generated during the degreasing process, so that the degreasing process can be implemented without the occurrence of residues, substrate damage, environmental pollution, etc. .

In the sludge removal apparatus according to embodiments of the present invention, a plurality of settling tanks are continuously arranged horizontally or vertically, and a magnet is disposed on a side or lower surface of the settling tank, so that sludge contained in the degreasing agent is effectively removed. can do.

1 and 3 are schematic cross-sectional views illustrating an apparatus for removing sludge according to exemplary embodiments.

Embodiments of the present invention are applicable at room temperature, including a surfactant including a copolymer structure including an oxyethylene group and an oxypropylene group as a repeating unit, and a hydrotrope containing gluconic acid, and improved degreasing properties and a degreasing agent having antifoaming properties. In addition, there is provided a sludge removal device for removing the sludge contained in the degreasing agent.

Hereinafter, embodiments of the present invention will be described in detail.

The degreasing agent according to exemplary embodiments may include an alkali agent, a surfactant including an anionic surfactant represented by the following Chemical Formula 1 and a nonionic surfactant represented by the following Chemical Formula 2, and a hydrotrope including sodium gluconate. have.

[Formula 1]

Wherein, EO is an oxyethylene group, PO is an oxypropylene group, a and b are each an integer of 0 to 20, R ₁ is an alkyl group having 8 to 16 carbon atoms, and M ⁺ may be a monovalent cation of an alkali metal. .

[Formula 2]

In the formula, EO is an oxyethylene group, PO is an oxypropylene group, m and n are each an integer from 1 to 19, m+n is an integer from 5 to 40, R ₂ and R ₃ are an alkyl group having 1 or more carbon atoms, The _{sum of carbon atoms of R 2} and R ₃ is 5 to 18, and R ₄ may be hydrogen or a methyl group.

In the above formulas, (EO) _a (PO) _b and (EO) _m (PO) _n mean a structure in which an oxyethylene group and an oxypropylene group are repeatedly bonded. In this case, the repeating order of the oxyethylene group and the oxypropylene group is not particularly limited.

The alkali agent may saponify, for example, rolling oil or rust-preventing oil present on the cold-rolled steel sheet. Accordingly, it is possible to more easily remove the rolling oil or rust preventive oil.

In some embodiments, the content of the alkali agent may be about 5 to 55% by weight based on the total weight of the degreasing agent. In the above range, the economical efficiency and stability of the degreasing agent may be excellent.

In some embodiments, the alkali agent may include at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium orthosilicate and sodium metasilicate.

The anionic surfactant represented by Formula 1 may reduce the generation of bubbles by, for example, reducing the surface tension of the system to about 32 dynes/cm or less. Accordingly, the degreasing agent easily penetrates into contaminants (eg, rolling oil or rust preventive oil) present on the cold-rolled steel sheet, so that the degreasing and defoaming properties of the degreasing agent can be further improved.

In some embodiments, the anionic surfactant is at least one selected from the group consisting of sodium dioctylsulfosuccinate, sodium alkyldiphenyloxidedisulfonate, sodium alkylbenzenesulfonate, and sodium fatty acid having 8 to 20 carbon atoms (soap). may include more.

The anionic surfactant, for example, has a relatively smaller particle size than the anionic surfactant represented by Chemical Formula 1, and thus can more easily penetrate into the contaminants while maintaining excellent defoaming properties.

In some embodiments, the anionic surfactant represented by Formula 1 may be included in an amount of about 70% by weight or more of the total anionic surfactant content, thereby simultaneously satisfying excellent degreasing properties and defoaming properties.

In some embodiments, the content of the anionic surfactant may be about 0.01 to 30% by weight based on the total weight of the degreasing agent. In the above range, a degreasing agent having excellent degreasing power and stability can be more easily implemented. Preferably, the content of the anionic surfactant may be about 0.01 to 20% by weight.

The nonionic surfactant represented by Formula 2 may be formed by combining a copolymer including oxyethylene and oxypropylene, which are hydrophilic groups, as repeating units, with a secondary alcohol. In this case, the _{hydrophilic group is positioned between the lipophilic groups R 2} and R ₃ , so that the nonionic surfactant can more easily penetrate between the contaminants. Accordingly, the degreasing property may be more improved than when a primary alcohol or a tertiary alcohol is used.

In addition, when R ₄ is a methyl group, it is possible to further reduce the foaming.

In some embodiments, the content of the nonionic surfactant may be about 0.01 to 30% by weight based on the total weight of the degreasing agent. In the above range, it is possible to more easily implement a degreaser having excellent defoaming properties and stability. Preferably, the content of the nonionic surfactant may be about 0.01 to 20% by weight.

In some embodiments, the surfactant may include an auxiliary surfactant including a polyoxyethylene-based nonionic surfactant. The auxiliary surfactant may supplement the degreasing power of the surfactant and prevent re-agglomeration of the rust preventive oil or rolling oil.

In some embodiments, the content of the auxiliary surfactant may be about 0.01 to 10% by weight based on the total weight of the degreasing agent. In the above range, it is possible to effectively prevent the occurrence of bubbles due to the addition of the auxiliary surfactant, and further improve the degreasing power.

In some embodiments, the polyoxyethylene-based nonionic surfactant may include at least one selected from the group consisting of polyoxyethylene lauryl ether, polyoxyethylene decyl ether and laureth methyl ether.

In some embodiments, the cloud point of the nonionic surfactant included in the degreasing agent may be about 40° C. or higher. The cloud point may be a temperature at which the solubility of the nonionic surfactant is reduced and the nonionic surfactant is precipitated cloudy. For example, when the cloud point is less than about 40° C., the nonionic surfactant may be precipitated during the degreasing process at room temperature, and the degreasing power of the degreasing agent may be reduced.

The hydrotrope may have a structure similar to that of a surfactant, but may be a low-molecular complex in which self-aggregation is not easy due to a small lipophilic portion. The hydrotrope may, for example, improve the solubility of the contaminant in water.

For example, sodium gluconate contained in the hydrotrope is a multifunctional organic salt and has excellent penetrating power, so that the alkali agent can easily penetrate into the contaminant.

The contaminants may be removed from the cold-rolled steel sheet by performing a saponification reaction with the alkali agent at room temperature (about 25° C. or higher). Accordingly, a highly efficient degreasing process without an additional heating or foam removal process can be implemented.

For example, the hydrotrope is ethylene glycol, propylene glycol, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethanolamine, 1,2-benzylisotriazole, sodium naphthalenesulfonate, sodium xylenesulfonate and poly It may further include at least one selected from the group consisting of oxyethylene ester-based phosphates.

In some embodiments, the content of the hydrotrope including sodium gluconate may be about 0.2 to 35% by weight based on the total weight of the degreasing agent. In the above range, it is possible to easily implement a room temperature desorbent having excellent stability and degreasing properties. Preferably, the content of the hydrotrope containing sodium gluconate may be about 0.01 to 25% by weight.

In some embodiments, the content of sodium gluconate may be about 70% by weight or more based on the total weight of the hydrotrope. In the above range, the effect of increasing the solubility of contaminants on the cold-rolled steel sheet is easily realized, so that the room temperature degreasing process can be easily performed.

In some embodiments, the degreasing agent may further include a metal remover or an antifoaming agent.

The metal remover prevents hardening of the degreasing agent by, for example, removing a hardness component introduced during the degreasing process.

For example, the metal removing agent is ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), sodium citrate, ethylenediamine, methylphosphonic acid and diphosphonic acid. It may include at least one selected from the group consisting of acids.

In some embodiments, the content of the metal remover may be about 0.01 to 5% by weight based on the total weight of the degreasing agent. In the above range, the excellent anti-hardening effect of the metal remover can be more easily implemented.

The antifoaming agent removes bubbles generated during the degreasing process, thereby preventing the surface of the cold-rolled steel sheet from being re-contaminated.

For example, the anti-foaming agent may include a silicone-based anti-foaming agent or a mineral oil-based anti-foaming agent. The silicone-based anti-foaming agent may be, for example, a silicone oil-based anti-foaming agent. For example, the mineral oil-based antifoaming agent may be an antifoaming agent obtained by emulsifying mineral oil or a fatty acid ester compound with a hydrophobic material.

In some embodiments, the content of the antifoaming agent may be about 0.01 to 5% by weight based on the total weight of the degreasing agent. In the above range, it is possible to easily prevent the generation of bubbles and recontamination by the antifoaming agent.

In some embodiments, the degreasing agent may be used after being diluted in a solvent. For example, the solvent may include purified water.

In some embodiments, the alkali agent included in the degreasing agent by the solvent may be diluted to about 0.8 to 3.8 wt% based on the total weight of the degreasing agent to which the concentration is diluted. Preferably, the alkali agent may be diluted to a concentration of about 1.5 to 2.5% by weight based on the total weight.

Hereinafter, a sludge removal apparatus for removing sludge contained in a degreasing agent according to exemplary embodiments will be described with reference to the drawings.

1 and 2, in the sludge removal apparatus 100, 200 according to some exemplary embodiments, the degreasing agent is injected, and at least one magnet 120, 130, 220 is disposed on the side or lower surface. It includes the settling tanks 110 and 210, and 1 to 15 of the settling tanks 110 and 210 may be continuously arranged in a horizontal direction (M) or a vertical direction (Y).

For example, the type of degreasing agent injected into the sludge removal apparatuses 100 and 200 is not particularly limited, but preferably, the above-described degreasing agent may be injected into the sludge removal apparatuses 100 and 200 .

For example, the sludge may include iron powder generated from the surface of the cold-rolled steel sheet during the degreasing process and hair loss generated during the brush roller process.

The magnets 120, 130, and 220 disposed on the side or lower surfaces of the settling tanks 110 and 210 may magnetically separate and precipitate the sludge contained in the degreasing agent. For example, the magnets 120 , 130 , and 220 may be permanent magnets or electromagnets.

In addition, the sludge separated on the wall surface of the settling tanks 110 and 210 by the magnets 120, 130 and 220 is to be removed after the magnets 120, 130, and 220 are separated from the settling tanks 110 and 210. can

Referring to FIG. 1 , 1 to 15 settling tanks 110 may be sequentially arranged in a horizontal direction (M). In this case, the degreasing agent may be injected into the settling tank 110 located at the outermost part of the plurality of settling tanks. The degreasing agent may be injected, for example, through the degreasing agent inlet 140 of the settling tank located at the outermost portion.

Referring to FIG. 1 , the degreasing agent injected into the settling tank 110 may move in the horizontal direction M along the continuously arranged settling tank 110 . The magnets 120 and 130 disposed on the side or the lower surface of the settling tank 110 may precipitate the sludge contained in the degreasing agent through magnetic force.

Referring to FIG. 1 , the degreasing agent from which the sludge has been removed may be discharged from the settling tank located at the end of the settling tanks 110 arranged in the horizontal direction (M). For example, the degreasing agent from which the sludge has been removed may be discharged through the degreasing agent outlet 150 of the settling tank 110 located at the end of the horizontal direction M.

Referring to FIG. 2 , the sludge removal device 200 includes a settling tank 210 in which the degreasing agent is injected, at least one magnet 220 is disposed on a lower surface, and 1 to 15 settling tanks 210 are vertical. They may be continuously arranged in the direction (Y).

Referring to FIG. 2 , the degreasing agent may be injected into the settling tank 210 located at the bottom of the settling tanks 210 continuously arranged in the vertical direction (Y). For example, the degreasing agent may be injected into the degreasing agent inlet 240 of the settling tank 210 located at the bottom.

Referring to FIG. 2 , the degreasing agent injected into the settling tank 210 may move along the settling tank 110 continuously arranged in the vertical direction (Y). The magnet 220 disposed on the lower surface of the settling tank 210 may precipitate the sludge contained in the degreasing agent through magnetic force.

Referring to FIG. 2 , the degreasing agent from which the sludge has been removed may be discharged from the settling tank 210 located at the top of the settling tanks 110 arranged in the vertical direction (Y). For example, the degreasing agent from which the sludge has been removed may be discharged through the degreasing agent outlet 250 of the settling tank 210 located at the uppermost end of the vertical direction Y.

In this case, the sludge contained in the degreasing agent is deposited in the lower part of the settling tank 210, and only the supernatant of the degreasing agent having a low concentration of the sludge can move to the upper part. Accordingly, the sludge removal efficiency can be improved.

Referring to FIG. 3 , the side heights of the settling tanks 310 may be gradually lowered according to the movement direction (X) of the degreasing agent.

Therefore, when an excess of the degreasing agent is injected than the volume of the precipitation tank 310 into which the degreasing agent is initially injected, the excess volume of the precipitation tank 310 overflows into the next settling tank 310 having a relatively low side height. can be Accordingly, only the supernatant having a low sludge concentration among the degreasing agent moves to the next settling tank 310, so that the sludge contained in the degreasing agent can be more easily removed.

In some embodiments, the volume of the settling tanks may be gradually reduced according to the direction of movement of the degreasing agent. In this case, the volume of the sedimentation tank in which the degreasing agent is first injected and excess sludge is deposited is the largest, whereas the volume of the sedimentation tank after a relatively small amount of sludge is settled may be relatively small. Accordingly, the cleaning cycle for sludge removal can be increased.

The settling tanks 110 and 210 included in the sludge removal apparatuses 100 and 200 according to some exemplary embodiments may repeatedly perform an actuator participating in the sludge removal process and a resting period not participating in the process.

For example, some of the settling tanks 110 and 210 correspond to the mover, and sludge may be deposited therein. For example, some of the settling tanks 110 and 210 may correspond to a rest period. After the magnets 120, 130, and 220 are separated from the settling tanks 110 and 210 corresponding to the resting period, the sludge deposited in the settling tanks 110 and 210 may be removed. In this case, it is not necessary to stop the sludge removal apparatus for removing the settled sludge, and thus the efficiency and economical efficiency of the sludge removal process can be improved.

In some exemplary embodiments, a plurality of sludge removal devices 100 and 200 may be additionally connected vertically or horizontally. In this case, the sludge removal rate may be further improved through the repeated settling process through the sludge removal devices 100 and 200 .

In some embodiments, the magnets 120 , 130 , 220 may be disposed on the outer wall of the sludge removal device 100 , 200 . In this case, the magnets 120 , 130 , and 220 may be detachable from the outer wall of the sludge removal device 100 , 200 . Accordingly, the sludge removal devices 100 and 200 may improve the sludge removal efficiency by adjusting the attachment positions of the magnets 120 , 1300 , 220 .

In some embodiments, the shape of the interior of the sludge removal devices 100 and 200 is not particularly limited. For example, the inside of the sludge removal apparatuses 100 and 200 may have a straight shape. For example, the inside of the sludge removal apparatuses 100 and 200 may have a winding shape as shown in FIG. 1 or FIG. 2 . For example, each settling tank 110 may be divided by a plurality of sides as shown in FIG. 3 in the interior of the sludge removal devices 100 and 200 .

100, 200,300: sludge removal device 110,210,310: sedimentation tank
120,130,220,320,330: magnet 140,240,340: degreaser inlet
150,250,350: degreaser outlet

Claims (18)

alkali agent;
a surfactant comprising an anionic surfactant represented by the following formula (1) and a nonionic surfactant represented by the following formula (2); and
A degreasing agent for cold-rolled steel sheet sludge removal comprising a hydrotrope containing sodium gluconate:
[Formula 1]

(Wherein, EO is an oxyethylene group, PO is an oxypropylene group, a and b are each an integer of 1 to 20, R ₁ is an alkyl group having 8 to 16 carbon atoms, and M ⁺ is a monovalent cation of an alkali metal)
[Formula 2]

(Wherein, EO is an oxyethylene group, PO is an oxypropylene group, m and n are each an integer from 1 to 19, m+n is an integer from 5 to 40, R ₂ and R ₃ are an alkyl group having 1 or more carbon atoms, The _{sum of carbon atoms of R 2} and R ₃ is 5 to 18, and R ₄ is hydrogen or a methyl group).
The method according to claim 1, wherein the content of the alkali agent is 5 to 55% by weight based on the total weight of the degreasing agent, the content of the anionic surfactant is 0.01 to 30% by weight, and the content of the nonionic surfactant is 0.01 to 30% by weight And, the content of the hydrotrope is 0.2 to 35% by weight, a degreasing agent for cold-rolled steel sheet sludge removal.
The degreasing agent for cold-rolled steel sheet sludge removal according to claim 1, wherein the alkali agent comprises at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium orthosilicate and sodium metasilicate.
The cold rolling according to claim 1, wherein the anionic surfactant further comprises at least one selected from the group consisting of sodium dioctylsulfosuccinate, sodium alkyldiphenyloxide disulfonate, sodium alkylbenzenesulfonate, and sodium fatty acid having 8 to 20 carbon atoms. Degreasing agent for steel plate sludge removal.
The degreasing agent for cold-rolled steel sheet sludge removal according to claim 1, wherein the surfactant further comprises an auxiliary surfactant including a polyoxyethylene-based nonionic surfactant.
The degreasing agent for cold-rolled steel sheet sludge removal according to claim 5, wherein the content of the auxiliary surfactant is 0.01 to 10% by weight based on the total weight of the degreasing agent.
The degreasing agent for cold-rolled steel sheet sludge removal according to claim 5, wherein the polyoxyethylene-based nonionic surfactant comprises at least one selected from the group consisting of polyoxyethylene lauryl ether, polyoxyethylene decyl ether, and laureth methyl ether.
The method according to claim 1, wherein the hydrotrope is ethylene glycol, propylene glycol, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethanolamine, 1,2-benzyl isotriazole, sodium naphthalenesulfonate, sodium xylenesulfonate and A degreasing agent for cold-rolled steel sheet sludge removal further comprising at least one selected from the group consisting of polyoxyethylene ester-based phosphates.
The degreasing agent for cold-rolled steel sheet sludge removal according to claim 1, wherein the content of sodium gluconate is 70% by weight or more based on the total weight of the hydrotrope.
The degreasing agent for cold-rolled steel sheet sludge removal according to claim 1, further comprising a metal removal agent or an antifoaming agent.
The degreasing agent for cold-rolled steel sheet sludge removal according to claim 10, wherein the content of the metal remover is 0.01 to 5% by weight and the content of the antifoaming agent is 0.01 to 5% by weight based on the total weight of the degreasing agent.
The method according to claim 10, wherein the metal removing agent is ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), sodium citrate, ethylenediamine, methylphosphonic acid and depot A degreasing agent for cold-rolled steel sheet sludge removal, comprising at least one selected from the group consisting of sonic acids.
The degreasing agent for cold-rolled steel sheet sludge removal according to claim 10, wherein the antifoaming agent comprises a silicone-based antifoaming agent or a fatty acid-based antifoaming agent.
A settling tank in which the degreasing agent for cold-rolled steel sheet sludge removal of claim 1 is injected, and at least one magnet is disposed on the side or lower surface,
The sludge removal device, wherein the settling tanks 1 to 15 are continuously arranged in a horizontal direction.
The sludge removal apparatus according to claim 14, wherein the side heights of the settling tanks are gradually lowered according to the moving direction of the degreasing agent for cold-rolled steel sheet sludge removal.
The sludge removal apparatus according to claim 14, wherein the volumes of the settling tanks are gradually decreased according to the moving direction of the degreasing agent for the cold rolled steel sheet sludge removal.
A settling tank in which the degreasing agent for cold-rolled steel sheet sludge removal of claim 1 is injected, and at least one magnet is disposed on the side or lower surface,
The sludge removal device, wherein the settling tanks 1 to 15 are continuously arranged in a vertical direction.
The settling tanks 1 to 15 in which the degreasing agent for cold-rolled steel sheet sludge removal of claim 1 are injected are continuously arranged in a vertical or horizontal direction,
A sludge removal device disposed on the outer wall of the settling tank and comprising at least one detachable magnet.

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