Pickling device and pickling method

Abstract

The present invention provides a pickling device for pickling a metal strip being transported, the pickling device comprising a pickling tank for storing an acid solution, an enclosing part provided in the pickling tank so as to surround the strip immersed in the acid solution in the pickling tank, and an oxidizing-agent-feeding unit for feeding a liquid oxidizing agent towards the interior of the enclosing part.

Description

[Technical field]

[0001] The present disclosure relates to a pickling apparatus and a pickling method. [Background technology]

[0002] In pickling metal (steel, etc.) strips, the ferric ions (Fe 3+ It is known that the pickling speed can be increased by adjusting the concentration of Fe in the acid solution. 3+ Methods have been proposed for adjusting the concentration.

[0003] For example, in Patent Document 1, the acid solution in the pickling tank is circulated through a conduit connected to the tank, and hydrogen peroxide water is supplied to the conduit, so that Fe in the acid solution is removed. 2+ Fe 3+ The Fe in the acid solution is oxidized to 3+ It is stated that the concentration is increased. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-170090 Summary of the Invention [Problem to be solved by the invention]

[0005] By the way, depending on how the liquid oxidizer such as hydrogen peroxide solution is supplied to the acid solution, the liquid oxidizer may 2+ is easily consumed in a reaction different from the oxidation of Fe 2+ In order to adequately oxidize the acid, a large amount of liquid supply must be supplied, making efficient pickling difficult.

[0006] In view of the above circumstances, an object of at least one embodiment of the present invention is to provide a pickling apparatus and a pickling method capable of more efficiently pickling a metal strip. [Means for solving the problem]

[0007] At least one embodiment of the pickling apparatus of the present invention comprises: A pickling apparatus for pickling a transported metal strip, comprising: a pickling tank for storing an acid solution; an enclosure provided in the pickling tank so as to surround the strip immersed in the acid solution in the pickling tank; an oxidizer supply unit for supplying a liquid oxidizer toward an inside of the enclosure; Equipped with.

[0008] Further, the pickling method according to at least one embodiment of the present invention includes: 1. A method for pickling a transported metal strip, comprising the steps of: a step of transporting the strip while the strip is immersed in an acid solution stored in a pickling tank and surrounded by an enclosure provided in the pickling tank; supplying a liquid oxidizer toward an interior of the enclosure; Equipped with. Effect of the Invention

[0009] According to at least one embodiment of the present invention, in view of the above circumstances, at least one embodiment of the present invention provides a pickling apparatus and a pickling method capable of more efficiently pickling a metal strip. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic configuration diagram of a pickling apparatus according to an embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view of the pickling apparatus shown in FIG. [Figure 3A] FIG. 2 is a schematic diagram of an enclosure and an oxidant supply section of a pickling apparatus according to an embodiment. [Figure 3B] FIG. 2 is a schematic diagram of an enclosure and an oxidant supply section of a pickling apparatus according to an embodiment. [Figure 4A] FIG. 2 is a schematic diagram of an enclosure and an oxidant supply section of a pickling apparatus according to an embodiment. [Figure 4B] FIG. 2 is a schematic diagram of an enclosure and an oxidant supply section of a pickling apparatus according to an embodiment. [Figure 5A] FIG. 2 is a schematic diagram of an enclosure and an oxidant supply section of a pickling apparatus according to an embodiment. [Figure 5B] FIG. 2 is a schematic diagram of an enclosure and an oxidant supply section of a pickling apparatus according to an embodiment. [Figure 6A] FIG. 2 is a schematic diagram of an enclosure and an oxidant supply section of a pickling apparatus according to an embodiment. [Figure 6B] FIG. 2 is a schematic diagram of an enclosure and an oxidant supply section of a pickling apparatus according to an embodiment. [Figure 7A] FIG. 2 is a schematic diagram of an enclosure and an oxidant supply section of a pickling apparatus according to an embodiment. [Figure 7B] FIG. 2 is a schematic diagram of an enclosure and an oxidant supply section of a pickling apparatus according to an embodiment. [Figure 8] FIG. 2 is a schematic diagram of an enclosure and an oxidant supply section of a pickling apparatus according to an embodiment. [Figure 9] FIG. 1 is a schematic configuration diagram of a pickling apparatus according to an embodiment. [Figure 10] FIG. 1 is a schematic configuration diagram of a pickling apparatus according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as the embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0012] Fig. 1 is a schematic configuration diagram of a pickling apparatus according to one embodiment, and Fig. 2 is a schematic cross-sectional view of the pickling apparatus shown in Fig. 1.

[0013] The pickling apparatus 1 shown in Fig. 1 is an apparatus for pickling a metal (e.g., steel) strip S with an acid solution 4. As shown in Fig. 1, the pickling apparatus 1 is equipped with a pickling tank 2 for storing the acid solution 4. The acid solution 4 is an acid solution for dissolving and removing scale (oxide film) formed on the surface of the strip S, and is a liquid containing an acid such as hydrochloric acid, sulfuric acid, nitric acid, or hydrofluoric acid.

[0014] The pickling apparatus 1 shown in Fig. 1 includes a skid 8 and transport rolls 6 for guiding and transporting the strip S immersed in the acid solution 4. The transport rolls 6 may be driven by a motor (not shown) or the like to apply tension to the strip S to transport the strip S. Note that the strip S may be transported by being moved only by a catenary due to its own weight to a depth where an enclosure is to be added, without including the transport rolls 6.

[0015] The pickling apparatus 1 shown in FIG. 1 further includes an enclosure 10 provided in the pickling tank 2, and an oxidizing agent supplying unit 50 for supplying a liquid oxidizing agent toward the inside of the enclosure 10.

[0016] The enclosure 10 is provided in the pickling tank 2 so as to surround the strip S immersed in the acid solution 4 in the pickling tank 2. The enclosure 10 forms a flow path 12 for the acid solution 4 along the conveying direction of the strip S (hereinafter also simply referred to as the conveying direction).

[0017] As shown in Fig. 1, the pickling apparatus 1 may include a plurality of enclosures 10 arranged in the conveying direction inside the pickling tank 2. In the exemplary embodiment shown in Fig. 1, four enclosures 10 are provided inside the pickling tank 2.

[0018] 2, the enclosure 10 includes an upper plate portion 20 and a lower plate portion 22 provided so as to cover both sides of the strip S, respectively, and a pair of side plate portions 24, 26 provided so as to connect the upper plate portion 20 and the lower plate portion 22 on both sides in the strip width direction of the strip S. A flow path 12 for the acid liquid 4 is formed by the inner surfaces of the upper plate portion 20, the lower plate portion 22, and the side plate portions 24, 26.

[0019] In some embodiments, as shown in Figures 1 and 2, a guide unit 16 for guiding the transported strip S is provided in the enclosure 10. The guide unit 16 may include a guide roll 17 or a receiving unit 18 (such as a skid) provided in the enclosure 10. In the exemplary embodiment shown in Figures 1 and 2, the guide unit 16 includes the guide roll 17 supported by the upper plate portion 20 (enclosure 10) and the receiving unit 18 supported by the lower plate portion 22 (enclosure 10).

[0020] The oxidizing agent supply unit 50 supplies Fe in the acid solution 4 toward the inside of the enclosure 10. 2+ Fe 3+ 1 and 2 includes an oxidizer tank 52 for storing liquid oxidizer, an oxidizer supply line 53 for directing the liquid oxidizer from the oxidizer tank 52 toward the inside of the enclosure 10, and an oxidizer pump 54 provided in the oxidizer supply line 53.

[0021] 1 and 2, the oxidizer supply unit 50 includes pipes 56 (56A, 56B) connected to the enclosure 10, and is configured to supply liquid oxidizer into the enclosure 10 via the pipes 56. In the embodiment shown in FIGS. 1 and 2, the pipe 56A is connected to the upper plate 20 that constitutes the enclosure 10. Furthermore, the pipe 56B is connected to the lower plate 22 that constitutes the enclosure 10.

[0022] As a liquid oxidizer, ferrous ions (Fe 2+ A liquid capable of oxidizing the oxygen can be used. The liquid oxidizer may be, for example, a liquid including at least one of hydrogen peroxide, hypochlorous acid, ammonium peroxodisulfate (ammonium persulfate), and potassium permanganate solution.

[0023] In the pickling apparatus 1 according to the above embodiment, the liquid oxidizing agent is supplied toward the inside of the enclosure 10 provided to surround the strip S in the pickling tank 2. This prevents the liquid oxidizing agent from diffusing outside the enclosure 10 in the pickling tank 2 and makes the liquid oxidizing agent tend to remain in the vicinity of the strip S. Therefore, Fe generated by the reaction between the liquid oxidizing agent and the acid solution 4 is easily removed. 3+ Since it is easy for the pickling material to come into contact with the strip S, pickling can be performed efficiently.

[0024] In addition, inside the enclosure 10, a flow of the acid liquid (entrained flow) is formed that accompanies the transported strip S, and the flow rate of the acid liquid 4 is relatively high. In this regard, in the above-mentioned embodiment, the liquid oxidizer is supplied toward the inside of the enclosure 10, so that the Fe in the liquid oxidizer and the acid liquid 4 can be easily mixed. 2+ This increases the chance of contact between the liquid oxidizer and the Fe 2+ Oxidation reaction of (Fe 3+ This makes it easier for the liquid oxidizer to be thermally decomposed or reacted with the acid in the acid solution, thereby preventing the liquid oxidizer from being wasted.

[0025] In this regard, the acid liquid 4 contains hydrochloric acid (HCl), and the liquid oxidizer is hydrogen peroxide (H 2 O 2 ) will be described as an example. That is, when the liquid oxidizing agent is supplied to the acid solution 4 in the pickling tank 2, the Fe 2+ is oxidized according to the following reaction formula (A). H 2 O 2 +2Fe 2+ +2HCl → 2H 2 O+2Fe 3+ +2Cl - …(A) On the other hand, the liquid oxidizing agent supplied to the acid liquid 4 can also be consumed by a thermal decomposition reaction (reaction formula (B) below) or a reaction with the acid constituting the acid liquid 4 (reaction formula (C) below). 2H 2 O 2 → 2H 2 O+O 2 …(B) H 2 O 2+2HCl → 2H 2 O+Cl 2 …(C) Here, the Fe in the liquid oxidizer and the acid liquid 4 2+ If the contact with the liquid oxidizer increases, the reaction rate of the Fe ions increases compared to the thermal decomposition of the liquid oxidizer (reaction (B)) and the reaction with the acid (reaction (C)). 2+ The oxidation reaction (reaction (A)) becomes relatively more likely to occur, and the liquid oxidizer becomes Fe through the reactions of reaction (B) and reaction (C). 2+ It is possible to suppress the consumption of the hydrogen without contributing to the oxidation reaction.

[0026] Therefore, according to the above-described embodiment, the pickling of the strip S can be carried out more efficiently.

[0027] 1 and 2, the pickling apparatus 1 may include a lid 30 that covers the pickling tank 2 from above. By covering the pickling tank 2 from above with the lid 30, loss of the acid solution 4 in the pickling tank 2 due to evaporation can be suppressed. The pickling apparatus 1 may also include a seal 40 that seals the space surrounded by the pickling tank 2 and the lid 30. By providing such a seal 40, loss of the acid solution 4 in the pickling tank 2 due to evaporation can be more effectively suppressed.

[0028] 2, the lid 30 may include an upper plate 20 constituting an upper portion of the enclosure 10. The lid 30 may include the upper plate 20 and a sealing plate 34 configured to be inserted from above into a tub 42 provided on the edge (upper end) of the pickling tank 2. The sealing portion 40 may include the tub 42 and the sealing plate 34, and may be configured to seal the space surrounded by the pickling tank 2 and the lid 30 by immersing the sealing plate 34 in a sealing liquid (water or the like) stored in the tub 42.

[0029] 2, the lid part 30 is provided so as to be able to be opened and closed integrally with the upper plate part 20 constituting the enclosure part 10. The pickling apparatus 1 may include an actuator for opening and closing the lid part 30.

[0030] In some embodiments, the flow path 12 formed by the enclosure 10 has a flow path reduction section 14 located downstream of an upstream end 10a of the enclosure 10 in the conveying direction and having a flow path cross-sectional area smaller than that of the upstream end 10a. Here, the flow path cross-sectional area is the area of ​​the flow path cross section of the flow path 12 perpendicular to the conveying direction. The flow path reduction section 14 may be formed by the above-mentioned guide section 16 provided in the enclosure 10. In the exemplary embodiment shown in Figs. 1 and 2, the flow path reduction section 14 is formed by a guide roll 17 (guide section 16) and a receiving section 18 (guide section 16).

[0031] In the above embodiment, the flow path 12 formed by the enclosure 10 has a flow path narrowing portion 14 located downstream of the upstream end 10a of the enclosure 10, so that a reverse flow is formed in the enclosure 10, in which the flow of the acid liquid 4 entrained by the strip S is reversed at the flow path narrowing portion 14 (guide roll 17 and receiving portion 18). This reverse flow agitates the acid liquid 4, so that the liquid oxidizer and the Fe in the acid liquid 4 are mixed together. 2+ Therefore, the contact opportunity with the liquid oxidizer is increased. 2+ This makes the oxidation reaction more likely to occur, and the pickling of the strip S can be carried out more efficiently.

[0032] Fig. 3A to Fig. 8 are schematic diagrams of the enclosure 10 and the oxidizing agent supply unit 50 of the pickling apparatus according to one embodiment. Fig. 3A, Fig. 4A, Fig. 5A and Fig. 8 are cross-sectional views including the conveying direction and the up-down direction (vertical direction), and Fig. 3B, Fig. 4B and Fig. 5B are plan views corresponding to Fig. 3A, Fig. 4A and Fig. 5A, respectively. Fig. 6A and Fig. 7A are front views, and Fig. 6B and Fig. 7B are cross-sectional views along the horizontal direction corresponding to Fig. 6A and Fig. 7A, respectively.

[0033] In the exemplary embodiment shown in FIGS. 3A to 7B, the oxidizing agent supply unit 50 has pipes 56 (56A to 56D) connected to the enclosure 10. The pipes 56 may be provided so as to penetrate members forming the enclosure 10 (the upper plate 20, the lower plate 22, or the side plates 24, 26, etc.). The pipes 56 may be supported by the pickling tank 2 or the lid 30. The liquid oxidizing agent is supplied to the inside of the enclosure 10 via the pipes 56.

[0034] In the exemplary embodiment shown in Fig. 8, the oxidizer supply unit 50 includes nozzles 57 (57A, 57B) provided at least partially on the upstream side of the enclosure 10 in the transport direction. The liquid oxidizer is ejected from an opening 55 of the nozzle 57 and supplied to the inside of the enclosure 10. As shown in Fig. 8, the opening 55 of the nozzle 57 may be located upstream of the upstream end 10a of the enclosure 10 in the transport direction, or may be located downstream of the upstream end 10a, or may be located at the same position as the upstream end 10a.

[0035] In some embodiments, the oxidant supply unit 50 may include a pipe 56A connected to the upper plate 20, or may include a pipe 56B connected to the lower plate 22. In the exemplary embodiment shown in FIGS. 3A-5B, the oxidant supply unit 50 includes a pipe 56A connected to the upper plate 20 and a pipe 56B connected to the lower plate 22.

[0036] In some embodiments, the oxidant supply unit 50 may include a pipe 56C or a pipe 56D connected to at least one of the side plate portions 24, 26. In the exemplary embodiment shown in Figures 6A to 7B, the oxidant supply unit 50 includes a pipe 56C and a pipe 56D connected to the side plate portions 24, 26, respectively.

[0037] 5A to 8, the oxidizer supplying unit 50 may be configured to supply the liquid oxidizer at a position upstream of the flow path narrowing section 14 in the conveying direction. In the exemplary embodiment shown in Fig. 5A to 8, the liquid oxidizer is supplied at a position upstream of the flow path narrowing section 14 in the conveying direction via a pipe 56 or a nozzle 57 (oxidizer supplying unit 50) connected to the enclosure 10 at a position upstream of the guide roll 17 and the receiving unit 18 that form the flow path narrowing section 14 in the conveying direction.

[0038] In this way, by supplying the liquid oxidizer at a position upstream of the narrowed flow passage 14, the acid solution 4 containing the liquid oxidizer is agitated by the reverse flow formed in the narrowed flow passage 14. Therefore, the liquid oxidizer and the Fe in the acid solution 4 are mixed together. 2+ The opportunities for contact with Fe 2+ Since the oxidation reaction occurs more easily, the pickling of the strip S can be carried out more efficiently.

[0039] In some embodiments, as shown in, for example, Figures 3A to 4B and 6A to 6B, the oxidizer supplying unit 50 may be configured to supply the liquid oxidizer at a position that is a distance from the upstream end 10a of the enclosure 10 that is greater than or equal to 0 and less than or equal to L / 2, where L is the length of the enclosure 10 in the transport direction.

[0040] In this way, by supplying the liquid oxidizer at a relatively upstream position having a length of 0 to L / 2 from the upstream end 10a of the enclosure 10, the liquid oxidizer supplied toward the inside of the enclosure 10 diffuses into the acid liquid 4 while traveling a relatively long distance of at least half the length of the enclosure 10 inside the enclosure 10. 2+ This will increase opportunities for contact with

[0041] 4A to 4B, for example, the oxidant supply unit 50 may include a plurality of pipes 56 connected to the enclosure 10 at different positions in the width direction of the strip S. In the exemplary embodiment shown in FIGS. 4A and 4B, the oxidant supply unit 50 includes a plurality of pipes 56A connected to the upper plate 20 (enclosure 10) at different positions in the width direction of the strip S, and a plurality of pipes 56B connected to the lower plate 22 (enclosure 10) at different positions in the width direction of the strip S.

[0042] In the enclosure 10, the acid solution 4 mainly flows in the transport direction of the strip S (i.e., the longitudinal direction of the strip S), so the diffusion speed of the liquid oxidizer supplied to the inside of the enclosure 10 in the strip width direction is smaller than the diffusion speed in the transport direction. According to the above-mentioned embodiment, the liquid supply agent is supplied into the enclosure 10 through a plurality of pipes 56 provided at different positions in the strip width direction, so that the concentration of the liquid oxidizer is easily uniformed in the strip width direction where the diffusion speed of the liquid oxidizer is small. Therefore, uniform pickling is easily performed in the strip width direction. In the enclosure 10, the acid solution flows mainly in the transport direction of the strip S (i.e., the longitudinal direction of the strip S) along with the strip S, but tends to flow mainly in the opposite direction to the transport direction of the strip S below the lower plate 22 of the enclosure 10 and outside both of the two side plate portions 24, 26 of the enclosure 10. In addition, by positioning the lid part 30 so that the upper plate part 10 of the lid part 30 is below the free liquid level of the acid liquid, the lid part 30 reduces the area of ​​the free liquid level of the acid liquid, so that the energy generated by the movement of the strip to entrain the acid liquid is used for the flow of the acid liquid without being consumed by the up and down movement of the free liquid level, etc., and the energy is efficiently converted into the flow of the acid liquid.

[0043] In some embodiments, as shown in FIG. 2, for example, a check valve 58 (58A, 58B) may be provided in the pipe 56 (oxidizer supply unit 50) connected to the enclosure 10. In the exemplary embodiment shown in FIG. 2, a check valve 58A is provided in the pipe 56A connected to the upper plate 20 (enclosure 10). Also, a check valve 58B is provided in the pipe 56B connected to the lower plate 22 (enclosure 10). In FIG. 2, the oxidizer supply line 53 is provided with valves 62A, 62B for adjusting the amount of liquid oxidizer supplied from the oxidizer tank 52 to the inside of the enclosure 10.

[0044] According to the embodiment described above, the check valve 58 is provided in the piping 56 for supplying the liquid oxidizer, so that it is possible to prevent the acid liquid from being mixed into the oxidizer supply line 53 for some reason (e.g., a decrease in the supply pressure of the liquid oxidizer, etc.).

[0045] In some embodiments, for example as shown in FIG. 2, a flexible hose 60 may be provided in the oxidizer supply line 53 between the piping 56A connected to the upper plate portion 20 and the oxidizer tank 52.

[0046] In the above embodiment, the flexible hose 60 is provided on the oxidizer supply line 53 between the piping 56A connected to the upper plate 20 and the oxidizer tank 52, so that the upper plate 20 of the enclosure 10 can be smoothly opened and closed together with the lid 30 while maintaining the state in which the enclosure 10 and the oxidizer tank 52 are connected via the piping 56A and the flexible hose 60. This makes it easy to inspect and maintain the inside of the pickling tank 2 and the enclosure 10.

[0047] In some embodiments, for example, as shown in FIG. 2, a flexible hose 60 may be provided on the oxidant supply line 53 upstream of the check valve 58 (on the oxidant tank 52 side).

[0048] In this way, by providing the flexible hose 60 upstream of the check valve 58, it is possible to prevent the acid liquid from entering the flexible hose 60, and it is possible to protect the flexible hose 60 from corrosion due to acid, etc.

[0049] 9 and 10 are schematic configuration diagrams of a pickling apparatus according to an embodiment.

[0050] In the exemplary embodiment shown in FIGS. 9 and 10 , the pickling apparatus 1 includes a pickling tank 2 for storing an acid solution 4, an enclosure 10 provided in the pickling tank 2, and an oxidizing agent supply unit 50 for supplying a liquid oxidizing agent toward the inside of the enclosure 10, similar to the pickling apparatus 1 shown in FIG. 1 .

[0051] 9 and 10 , the pickling apparatus 1 further includes an acid circulation line 72 configured to extract the acid 4 from the pickling tank 2 and return the acid 4 toward the inside of the enclosure 10 in the pickling tank 2. The acid circulation line 72 is provided with an acid circulation pump 74. The acid 4 extracted from the pickling tank 2 is supplied to the inside of the enclosure 10 via the acid circulation line 72 and a pipe 76 connected to the enclosure 10.

[0052] According to the above-described embodiment, the acid solution 4 extracted from the pickling tank 2 is returned to the inside of the enclosure 10 through the acid solution circulation line 72, so that the agitation of the acid solution 4 inside the enclosure 10 can be promoted. As a result, the liquid oxidizing agent supplied to the inside of the enclosure 10 and the Fe in the acid solution 4 are mixed together. 2+ The opportunities for contact with Fe 2+ This makes it easier for the oxidation reaction to occur, and therefore the pickling of the strip S can be carried out more efficiently.

[0053] In some embodiments, as shown in FIG. 10, for example, the oxidizer supply unit 50 may include a pipe 64 connected to the acid liquid circulation line 72 and may be configured to supply the liquid oxidizer toward the inside of the enclosure 10 through the acid liquid circulation line 72. In the exemplary embodiment shown in FIG. 10, the oxidizer supply unit 50 includes a pipe 64 connecting the oxidizer tank 52 and the acid liquid circulation line 72. In the exemplary embodiment shown in FIG. 10, a pipe 76 connected to the enclosure 10 for returning the acid liquid 4 from the acid liquid circulation line 72 to the inside of the enclosure 10 also functions as the pipe 56 for supplying the liquid oxidizer to the inside of the enclosure 10. In addition, a portion of the acid liquid circulation line 72 downstream of the connection with the pipe 64 functions as the oxidizer supply line 53.

[0054] According to the above-described embodiment, the liquid oxidizer is mixed into the acid liquid 4 through the piping 64 connected to the acid liquid circulation line 72, so that the liquid oxidizer can be supplied toward the inside of the enclosure 10 with a relatively simple configuration.

[0055] Below, an overview of pickling apparatuses and pickling methods according to some embodiments will be provided.

[0056] (1) At least one embodiment of the pickling apparatus (1) according to the present invention comprises: A pickling apparatus for pickling a transported metal strip (S), comprising: a pickling tank (2) for storing an acid solution (4); an enclosure (10) provided in the pickling tank so as to surround the strip immersed in the acid solution in the pickling tank; an oxidizer supply section (50) for supplying a liquid oxidizer toward the inside of the enclosure; Equipped with.

[0057] In the above configuration (1), the liquid oxidizing agent is supplied toward the inside of the enclosure that is provided to surround the strip in the pickling tank. This prevents the liquid oxidizing agent from diffusing outside the enclosure in the pickling tank and makes it more likely to remain in the vicinity of the strip. As a result, the Fe generated by the reaction between the liquid oxidizing agent and the acid solution is reduced. 3+Since the contact with the strip is easy, pickling can be performed efficiently. In addition, inside the enclosure, a flow of the acid liquid (entrained flow) is formed along with the transported strip, and the flow rate of the acid liquid is relatively fast. In this respect, in the above-mentioned configuration (1), the liquid oxidizer is supplied toward the inside of the enclosure, so that the Fe in the liquid oxidizer and the acid liquid can be easily mixed. 2+ This increases the chance of contact between the Fe and the liquid oxidizer. 2+ Oxidation reaction of (Fe 3+ This makes it easier for the liquid oxidizer to be thermally decomposed or reacted with the acid in the acid solution, thereby preventing the liquid oxidizer from being wasted. Therefore, according to the above configuration (1), the pickling of the strip can be carried out more efficiently.

[0058] (2) In some embodiments, in the configuration of (1) above, The surrounding portion forms a flow path (12) for the acid solution along a conveying direction of the strip, The flow path has a flow path narrowing portion (14) located downstream of an upstream end (10a) of the enclosure in the transport direction and having a flow path cross-sectional area smaller than that of the upstream end.

[0059] According to the above-mentioned configuration (2), the flow path formed by the enclosure has a flow path narrowing portion located downstream of the upstream end, so that a reverse flow is formed in the enclosure, in which the entrained flow of the acid liquid is reversed at the flow path narrowing portion. This reverse flow stirs the acid liquid, so that the liquid oxidizer and the Fe in the acid liquid are mixed together. 2+ Therefore, the contact opportunity with the liquid oxidizer is increased. 2+ This makes the oxidation reaction more likely to occur, and the pickling of the strip can be carried out more efficiently.

[0060] (3) In some embodiments, in the configuration of (2) above, The pickling apparatus comprises: a guide portion (16) provided in the enclosure for guiding the strip; The flow passage narrowing portion is formed by the guide portion.

[0061] According to the above configuration (3), the flow path reduction portion is formed by utilizing the guide portion provided within the enclosure portion, so that efficient pickling of the strip can be achieved with a simple configuration.

[0062] (4) In some embodiments, in the configuration of (2) or (3), The oxidizer supplying section is configured to supply the liquid oxidizer at a position upstream of the flow path narrowing section in the transport direction.

[0063] According to the above configuration (4), the liquid oxidizer is supplied at a position upstream of the narrowed flow passage, so that the acid solution containing the liquid oxidizer is agitated by the reverse flow formed in the narrowed flow passage. 2+ The opportunities for contact with Fe 2+ This makes it easier for the oxidation reaction to occur, so that the pickling of the strip can be carried out more efficiently.

[0064] (5) In some embodiments, in any one of the configurations (1) to (4) above, The oxidizer supplying section is configured to supply the liquid oxidizer at a position whose length from an upstream end of the enclosing section is equal to or greater than 0 and equal to or less than L / 2, where L is the length of the enclosing section in the transport direction.

[0065] According to the above configuration (5), the liquid oxidizer is supplied at a relatively upstream position having a length from the upstream end of the enclosure of 0 to L / 2. Therefore, the liquid oxidizer supplied toward the inside of the enclosure diffuses into the acid solution while traveling a relatively long distance of at least half the length of the enclosure inside the enclosure. Therefore, the liquid oxidizer and the Fe in the acid solution are mixed. 2+ This will increase opportunities for contact with

[0066] (6) In some embodiments, in any of the configurations (1) to (5) above, The oxidizer supply includes at least one pipe (56) connected to the enclosure and is configured to supply the liquid oxidizer into the enclosure via the pipe.

[0067] According to the above configuration (6), by supplying a liquid oxidizing agent into the enclosure through a pipe connected to the enclosure, the pickling of the strip can be performed more efficiently, as described in the above configuration (1).

[0068] (7) In some embodiments, in the configuration of (6), The at least one pipe includes a plurality of pipes connected to the surrounding portion at different positions in the plate width direction of the band plate.

[0069] In the enclosure, the acid solution flows mainly in the transport direction of the strip (i.e., the longitudinal direction of the strip), so the diffusion speed of the liquid oxidizer supplied inside the enclosure in the strip width direction is smaller than the diffusion speed in the transport direction. According to the configuration of (7) above, the liquid supply agent is supplied into the enclosure through multiple pipes provided at different positions in the strip width direction, so that the concentration of the liquid oxidizer can be made uniform in the strip width direction where the diffusion speed of the liquid oxidizer is small. This makes it easier to perform uniform pickling in the strip width direction.

[0070] (8) In some embodiments, in the configuration of (1) above, The pickling apparatus comprises: A check valve (58) is provided in the at least one pipe.

[0071] According to the above configuration (8), since the check valve is provided in the piping for supplying the liquid oxidizer, it is possible to prevent the acid liquid from being mixed into the liquid oxidizer supply line for some reason.

[0072] (9) In some embodiments, in any of the configurations (1) to (8) above, The surrounding portion includes an upper plate portion (20) and a lower plate portion (22) arranged to cover both sides of the band plate, and a pair of side plate portions (24, 26) arranged to connect the upper plate portion and the lower plate portion on both sides of the band plate.

[0073] According to the above configuration (9), the pickling of the strip can be performed more efficiently, as described in the above configuration (1), by using a simple enclosure including an upper plate portion, a lower plate portion, and a pair of side plate portions.

[0074] (10) In some embodiments, in the configuration of (9), The oxidant supply section includes a pipe (56A, 56B) penetrating at least one of the upper plate section and the lower plate section.

[0075] According to the above-mentioned (10) configuration, the liquid oxidizing agent can be supplied from above or below the strip inside the enclosure through the piping connected to the upper or lower plate, thereby making it possible to more efficiently pickle the strip as described in the above-mentioned (1).

[0076] (11) In some embodiments, in the configuration of (9) or (10), The oxidant supply section includes a pipe (56C, 56D) penetrating at least one of the pair of side plate sections.

[0077] According to the above-mentioned configuration (11), the liquid oxidizing agent can be supplied from the side of the strip inside the enclosure through a pipe connected to at least one of the pair of side plates, which allows the pickling of the strip to be performed more efficiently as described in the above-mentioned (1).

[0078] (12) In some embodiments, in any one of the configurations (9) to (11) above, The pickling apparatus comprises: A lid (30) is provided to cover the pickling tank from above, The cover is provided integrally with the upper plate so as to be openable and closable, The oxidant supply unit is an oxidizer tank (52) for storing the liquid oxidizer; A pipe (56A) connected to the upper plate portion; a flexible hose (60) provided between the oxidizer tank and the piping; Includes.

[0079] According to the above configuration (12), a flexible hose is provided between the piping connected to the upper plate portion and the oxidizer tank, so that the upper plate portion of the enclosure portion can be smoothly opened and closed together with the lid portion while maintaining the enclosure portion and the oxidizer tank connected via the piping and the flexible hose.

[0080] (13) In some embodiments, in any one of the configurations (1) to (12) above, The pickling apparatus comprises: The pickling tank includes an acid circulation line (72) configured to extract the acid from the pickling tank and return the acid to the inside of the enclosure in the pickling tank.

[0081] According to the above configuration (13), the acid liquid is returned to the inside of the enclosure through the acid liquid circulation line, so that the agitation of the acid liquid inside the enclosure can be promoted. As a result, the liquid oxidizer supplied to the inside of the enclosure and the Fe in the acid liquid can be mixed with each other. 2+ The opportunities for contact with Fe 2+ This makes it easier for the oxidation reaction to occur, so that the pickling of the strip can be carried out more efficiently.

[0082] (14) In some embodiments, in the configuration of (13), The oxidant supply unit includes a pipe (64) connected to the acid liquid circulation line, and is configured to supply the liquid oxidant toward the inside of the enclosure via the acid liquid circulation line.

[0083] According to the above configuration (14), the liquid oxidizer is mixed into the acid liquid through a pipe connected to the acid liquid circulation line, so that the above configuration (1) can be realized with a relatively simple configuration.

[0084] (15) At least one embodiment of the pickling method of the present invention comprises: 1. A method for pickling a transported metal strip, comprising the steps of: a step of transporting the strip while the strip is immersed in an acid solution stored in a pickling tank and surrounded by an enclosure provided in the pickling tank; supplying a liquid oxidizer toward an interior of the enclosure; Equipped with.

[0085] According to the method of (15) above, the liquid oxidizing agent is supplied toward the inside of the enclosure that is provided to surround the strip in the pickling tank, so that the liquid oxidizing agent is prevented from diffusing out of the enclosure in the pickling tank and tends to remain in the vicinity of the strip. Therefore, the Fe generated by the reaction between the liquid oxidizing agent and the acid solution can be prevented from being diffused out of the enclosure. 3+ Since the contact with the plate is easy, pickling can be performed efficiently. In addition, inside the enclosure, a flow of the acid liquid (entrained flow) is formed that accompanies the transported strip, and the flow rate of the acid liquid is relatively fast. In this regard, in the method (15) above, the liquid oxidizer is supplied toward the inside of the enclosure, so that the Fe in the liquid oxidizer and the acid liquid can be easily mixed. 2+ This increases the chance of contact between the Fe and the liquid oxidizer. 2+ Oxidation reaction of (Fe 3+ This makes it easier for the liquid oxidizer to be thermally decomposed or reacted with the acid in the acid solution, thereby preventing the liquid oxidizer from being wasted. Therefore, according to the method of (15) above, the pickling of the strip can be carried out more efficiently.

[0086] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0087] In this specification, expressions expressing relative or absolute configuration, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," do not only strictly represent such a configuration, but also represent a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions indicating that things are in an equal state, such as "identical," "equal," and "homogeneous," not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. Furthermore, in this specification, expressions describing shapes such as a rectangular shape or a cylindrical shape do not only refer to shapes such as a rectangular shape or a cylindrical shape in the strict geometric sense, but also refer to shapes that include uneven portions, chamfered portions, etc., to the extent that the same effect is obtained. In addition, in this specification, the expressions "comprise," "include," or "have" a certain element are not exclusive expressions that exclude the presence of other elements. [Explanation of symbols]

[0088] 1 Pickling equipment 2 Pickling tank 4 Acid liquid 6 Transport roll 8. Skid 10 Enclosure 10a Upstream end 12 Flow Path 14 Flow path reduction section 16 Guide section 17 Guide Roll 18 Receiving part 20 Upper plate 22 Lower plate part 24 Side plate part 26 Side plate part 30 Lid 34 Seal plate 40 Seal part 42 Okebe 50 Oxidant supply section 52 Oxidizer Tank 53 Oxidizer supply line 54 Oxidizer Pump 55 Aperture 56,56A~56D Piping 57 Nozzle 58, 58A, 58B Check valve 60 Flexible Hose 62A, 62B Valve 64 Piping 72 Acid circulation line 74 Acid Circulation Pump 76 Piping S strip

Claims

1. A pickling apparatus for pickling a transported metal strip, comprising: a pickling tank for storing an acid solution; an enclosure provided in the pickling tank so as to surround the strip immersed in the acid solution in the pickling tank; an oxidizer supply unit for supplying a liquid oxidizer toward an inside of the enclosure; Equipped with The surrounding portion includes an upper plate portion and a lower plate portion provided so as to cover both sides of the band plate, and a pair of side plate portions provided so as to connect the upper plate portion and the lower plate portion on both sides of the band plate. Pickling equipment.

2. The surrounding portion forms a flow path for the acid solution along a conveying direction of the strip, The flow path has a flow path narrowing portion located downstream of an upstream end of the enclosing portion in the transport direction and having a flow path cross-sectional area smaller than that of the upstream end.

2. The pickling apparatus according to claim 1.

3. A guide portion is provided in the surrounding portion and configured to guide the band plate, The flow passage narrowing portion is formed by the guide portion.

3. The pickling apparatus according to claim 2.

4. The oxidizer supply unit is configured to supply the liquid oxidizer at a position upstream of the flow path narrowing unit in the transport direction.

4. The pickling apparatus according to claim 2 or 3.

5. The oxidizer supply unit is configured to supply the liquid oxidizer at a position that is a distance from an upstream end of the enclosure to a length of 0 to L / 2, where L is a length of the enclosure in the transport direction of the strip.

5. A pickling apparatus according to claim 1 .

6. The oxidizer supply unit includes at least one pipe connected to the enclosure and is configured to supply the liquid oxidizer into the enclosure via the pipe.

6. A pickling apparatus according to claim 1 .

7. The at least one pipe includes a plurality of pipes connected to the surrounding portion at different positions in the plate width direction of the band plate.

7. The pickling apparatus according to claim 6.

8. A check valve is provided in the at least one pipe.

8. The pickling apparatus according to claim 6 or 7.

9. The oxidant supply unit includes a pipe penetrating at least one of the upper plate unit and the lower plate unit.

9. A pickling apparatus according to any one of claims 1 to 8.

10. The oxidant supply unit includes a pipe that penetrates at least one of the pair of side plate portions.

10. A pickling apparatus according to any one of claims 1 to 9.

11. A lid portion is provided to cover the pickling tank from above, The cover is provided integrally with the upper plate so as to be openable and closable, The oxidant supply unit is an oxidizer tank for storing the liquid oxidizer; A pipe connected to the upper plate portion; A flexible hose provided between the oxidizer tank and the piping; Includes 11. A pickling apparatus according to any one of claims 1 to 10.

12. The pickling tank includes an acid circulation line configured to extract the acid from the pickling tank and return the acid to the inside of the enclosure in the pickling tank.

12. A pickling plant according to any one of claims 1 to 11.

13. The oxidizer supply unit includes a pipe connected to the acid liquid circulation line, and is configured to supply the liquid oxidizer toward the inside of the enclosure through the acid liquid circulation line.

13. The pickling apparatus according to claim 12.

14. 1. A method for pickling a transported metal strip, comprising the steps of: a step of transporting the strip while the strip is immersed in an acid solution stored in a pickling tank and surrounded by an enclosure provided in the pickling tank; supplying a liquid oxidizer toward an interior of the enclosure; Equipped with The surrounding portion includes an upper plate portion and a lower plate portion provided so as to cover both sides of the band plate, and a pair of side plate portions provided so as to connect the upper plate portion and the lower plate portion on both sides of the band plate. Pickling method.

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