CN101484615A - Apparatus for regenerating plating solution and method for regenerating plating solution - Google Patents

Abstract

A plating solution regenerating apparatus for electroplating, comprising a circulation tank, a sludge removing unit, a concentrating unit, an iron compound crystallizing unit, an iron compound separating unit, an iron compound re-dissolving unit, an iron ion removing unit, a piping started with the circulation tank and sequentially connecting these units so that the recited order agrees with the downstream direction, a piping connecting the iron ion removing unit to the circulation tank, a piping connecting the iron compound separating unit to the circulation tank, and a flow channel changing unit connected to the circulation tank and disposed at at least one interspace selected from the group consisting of the interspace between the sludge removing unit and the concentrating unit, the interspace between the concentrating unit and the iron compound crystallizing unit and the interspace between the iron compound crystallizing unit and the iron compound separating unit. This apparatus is capable of removing sludge and iron contents from the plating solution used in electroplating of steel strip to thereby regenerate the plating solution. Further, by the use of this apparatus, continuous operation of electroplating can be maintained without lowering of the utilization rate of the sludge removing unit even when the operation of unit for iron contents removal is halted.

Description

Plating solution regeneration device and plating solution regeneration method

technical field

The present invention relates to a regenerating device and a regenerating method for reusing a plating solution used in electroplating of a steel strip.

Background technique

In order to continuously electroplate the steel strip (such as tin plating, chrome plating, zinc plating, copper plating, etc.), the electrolyte liquid is accumulated in the plating tank in advance, and the steel strip is run in the liquid, and the steel plate is set as the cathode , using the metal to be plated (such as tin, chromium, zinc, copper, etc.) disposed opposite to the steel strip as an anode and applying a voltage. A tin-plated steel strip is also called tinplate, but a plated steel strip is hereinafter referred to as a plated steel strip.

During the electroplating operation, sludge is mixed into the electrolytic liquid (hereinafter referred to as plating solution) accumulated in the plating tank. Here, the sludge refers to a substance in which oxides of the metal to be plated float or settle in the plating solution and accumulate. For example, in the case of tin plating, Sn(OH) ₄ and the like become sludge. When the amount of sludge in the plating solution increases, problems such as scratches and other problems that affect the quality will occur.

Therefore, various studies are being conducted on techniques for removing sludge in a plating solution from a plating tank.

For example, JP-A-62-74486 describes a technique of separating and removing sludge using a centrifuge. However, since the viscosity of the sludge is often high, not only a powerful centrifugal separator capable of separating the sludge is required, but also a long period of time is required to separate the sludge.

In addition, JP-A-2004-59940 describes a technique of precipitating and removing sludge using a sedimentation tank. However, since it takes a long time to settle the sludge, it is generally necessary to install a plurality of sedimentation tanks in order to shorten the treatment time.

Moreover, not only sludge exists in the plating solution, but also metal ions and iron ions to be plated exist. Among these ions, metal ions to be plated (such as tin ions, chromium ions, zinc ions, copper ions, etc.) that form a coating on the surface of the steel strip do not need to be removed. The iron ions are dissolved due to the reaction between the steel strip and the components of the plating solution, which will damage the electrolytic properties of the plating solution, thereby causing the quality of the coating on the surface of the coated steel strip to deteriorate. However, in the above-mentioned two techniques, the removal of the iron ions is not considered.

In order to recycle the plating solution while continuously performing electroplating on the steel strip, it is necessary to remove not only the sludge in the plating solution but also iron ions from the plating tank. It is difficult to simultaneously remove sludge and iron ions with a single device, and therefore, it is necessary to divide the sludge removal step and the iron ion removal step into a series of steps and perform these steps continuously. For this reason, it is necessary to arrange each dedicated removing device in series and operate it simultaneously so that the plating solution is continuously supplied to each device.

In this way, when the device for removing sludge and the device for removing iron ions are installed in series to regenerate the plating solution, if any one device breaks down, the entire plating solution regeneration process has to be stopped, so that the electroplated steel strip Productivity drops.

The object of the present invention is to provide a regeneration device and regeneration method of a plating solution, which can remove sludge and iron components from the plating solution used in the electroplating of steel strips, thereby allowing the plating solution to be reused, and The productivity of the plated steel strip can be improved.

Contents of the invention

The present invention provides a plating solution regeneration device for electroplating, which has a circulation tank, a sludge removal device, a concentration device, an iron compound crystallization device, an iron compound separation device, an iron compound redissolution device, an iron ion removal device, Taking the circulation tank as the base point and sequentially connecting the pipelines of these devices in the above order in the downstream direction, the pipeline connected to the circulation tank from the iron ion removal device, the pipeline connected to the circulation tank from the iron compound separation device, and At least one selected from the group consisting of between the sludge device and the concentration device, between the concentration device and the iron compound crystallization device, and between the iron compound crystallization device and the iron compound separation device is connected to the Flow channel changing device for circulation tank.

In addition, in the plating solution regenerating device, it is preferable that the channel changing device is provided between the sludge removing device and the concentrating device. Alternatively, it is preferable to install the channel changing device between the concentrating device and the iron compound crystallizing device. Alternatively, it is preferable to install the channel changing device between the iron compound crystallization device and the iron compound separation device.

In addition, in any one of the above-mentioned plating solution regenerating devices, it is more preferable to have a flow path changing device connected to the circulation tank between the iron compound redissolving device and the iron ion removing device.

Moreover, the present invention also provides a plating solution regeneration device for reusing the used plating solution for electroplating a steel strip, which is characterized in that it has a circulation tank for accumulating the plating solution, and the circulation A sludge removal device for removing sludge in the plating solution supplied from a tank, a plating solution concentration device for concentrating the plating solution supplied from the sludge removal device, and a plating solution concentration device for concentrating the plating solution supplied from the plating solution concentration device an iron component separating device for cooling the plating solution and depositing an iron compound, an iron component separating device for separating the iron compound from the plating solution supplied from the iron component separating device and redissolving it in water, The ion exchange resin removes iron ions from the redissolved solution supplied from the iron component separating device, and has a flow path changing device for feeding the plating solution from the plating solution concentrating device to the circulation tank.

In addition, the present invention also provides an operation method of a plating solution regeneration device, wherein, in any of the above-mentioned plating solution regeneration devices, the device selected from the concentration device, the iron compound crystallization device, the iron compound separation device, the iron When at least one device in the group consisting of the compound redissolving device and the iron ion removal device is stopped, it is further upstream of the most upstream stop device, and is selected between the sludge removal device and the concentration device, At least one of the group consisting of the concentration device and the iron compound crystallization device, and the iron compound crystallization device and the iron compound separation device switches the flow path of the plating solution to the circulation tank.

In addition, in the operation method of the plating solution regeneration device, it is preferable to use at least one device selected from the group consisting of the iron compound crystallization device, the iron compound separation device, the iron compound redissolving device and the iron ion removal device When stopping, it is further upstream of the most upstream stop device, and is selected from between the sludge removal device and the concentration device, between the concentration device and the iron compound crystallization device, the iron compound crystallization device and the At least one of the groups of iron compound separating devices switches the flow path of the plating solution to the circulation tank. Or, preferably, when at least one device selected from the group consisting of the iron compound separating device, the iron compound redissolving device, and the iron ion removing device is stopped, further upstream of the most upstream stopping device, and At least one selected from the group consisting of between the sludge removal device and the concentration device, between the concentration device and the iron compound crystallization device, and between the iron compound crystallization device and the iron compound separation device, The flow path of the plating solution is switched to this circulation tank.

In addition, in the operation method of any one of the above-mentioned plating solution regeneration devices, it is more preferable that when the iron ion removal device is stopped, the flow of the redissolution solution between the iron compound redissolution device and the iron ion removal device is further preferably The channel switches to the circulation tank.

In addition, in any one of the above-mentioned operation methods of the plating solution regeneration device, it is preferable that the plating solution is an electroplating solution containing tin methanesulfonate.

Moreover, the present invention also provides a method for regenerating a plating solution for reusing a used plating solution for electroplating a steel strip, wherein the plating solution accumulated in a circulation tank is supplied to the sludge After the removal device removes the sludge in the plating solution, the plating solution is supplied to the plating solution concentrating device to concentrate the plating solution, and then the plating solution is supplied to the iron component analysis device to make the iron in the plating solution The iron compound is precipitated in the form of iron compound, and the iron component separation device is further supplied with the plating solution to separate the iron compound, and the separated iron compound is redissolved in water to make a redissolving solution, and the redissolving solution is supplied to the iron component removal means and iron ions are removed by an ion exchange resin, and at the same time, the plating solution from which the iron compound has been removed in the iron component separation means and the plating solution from which the iron ions have been removed in the iron component removal means The redissolved solution is sent to the circulation tank. On the other hand, when the iron component separating device, the iron component separating device, or the iron component removing device is stopped, the plating solution concentrating device is sent to the The circulation tank transports the plating solution.

Description of drawings

Fig. 1 is a flowchart showing an example of an apparatus for removing sludge and iron ions to which the present invention is applied.

Fig. 2 is a flow chart illustrating another apparatus for removing sludge and iron ions using the present invention.

Fig. 3 is a flow chart illustrating another apparatus for removing sludge and iron ions using the present invention.

Fig. 4 is a flowchart showing the means used for the comparison.

Detailed ways

The plating solution used when electroplating steel strip contains metal ions to be plated, so it is conductive. As the electroplating operation proceeds, sludge and iron ions are inevitably mixed into the plating solution. When sludge and iron ions are mixed into the plating solution, it will adversely affect the properties of the steel strip surface and the electrolytic properties of the plating solution, and hinder the electroplating operation. Therefore, it is necessary to remove the sludge and iron ions from the plating solution.

The invention is applied to electroplating such as tin plating, chrome plating, zinc plating and copper plating. Especially preferred for tin plating which is prone to sludge and iron ion problems. In addition, as tin plating, it is preferably applied to a plating solution such as a methanesulfonic acid plating solution, a halogen plating solution, or a phenolsulfonic acid plating solution. In particular, the pH of the methanesulfonic acid plating solution is low, and the dissolution of iron is prone to occur, so the present invention is preferably applied to the methanesulfonic acid plating solution. Next, a case where the present invention is applied to a tin methanesulfonate plating solution will be described.

In the present invention, the plating solution contained in the plating tank is temporarily stored in the circulation tank, and the plating solution is sent to the device for removing sludge and iron ions. Further, after removing sludge and iron ions and returning the regenerated plating solution to the circulation tank, it is circulated to the plating tank.

Fig. 1 is a flowchart showing an example of a procedure for removing sludge and iron ions by applying the present invention. 1 shows an example of installing the pump 9 on the discharge side of the circulation tank 1, but the position and number of the pumps 9 can be appropriately set according to the flow rate of the plating solution 10 or the specifications of each device described later. In addition, illustration of the plating tank is omitted.

The plating solution 10 is supplied from the circulation tank 1 to the sludge removal device 2 . The sludge removal device 2 is a device for removing sludge in the plating solution 10, and conventionally known equipment such as a filter, a filter press, and a centrifugal separator are used. However, when considering the viscosity and particle size of the sludge, it is preferable to use a filter press.

On the discharge side (downstream) of the sludge removal device 2, valves 13a, 13b as flow path changing means 13 and pipes connected to the circulation tank are provided. When a series of devices described later are in operation, the valve 13b is closed and the valve 13a is opened. Therefore, the plating solution 10 is supplied from the sludge removing device 2 to the plating solution concentrating device 3 . The plating solution concentration device 3 is a device for concentrating the plating solution 10, and it is preferable to use a device capable of vaporizing water by heating or vacuum distillation. This concentration facilitates precipitation of the iron compound 11 in the iron compound crystallization device 4 (also referred to as an iron component precipitation device) to be described later. The concentration ratio of the plating solution 10 in the plating solution concentrating device 3 may be appropriately set according to the flow rate of the plating solution 10 or the specifications of each device described later. However, if it is over-concentrated, the consumption of heat energy will increase, leading to an increase in cost. In the case of the tin methanesulfonate plating solution, the standard is to concentrate to about 4 times the concentration of methanesulfonic acid in the plating solution 10 supplied from the sludge removal device 2 .

In the present invention, the plating solution 10 is concentrated after removing sludge in the plating solution 10 . The reason is that if the plating solution 10 mixed with sludge is supplied to the plating solution concentration device 3 , subsequent removal of the iron component becomes difficult.

In addition, what is shown in FIG. 1 is an example in which valves 13a, 13b are provided as components of the channel changing device 13, but the channel changing device 13 used in the present invention is not limited to valves, and conventional valves for changing fluid flow can be used. Road devices (such as valve opening and closing devices, etc.).

The plating solution 10 concentrated in the plating solution concentration device 3 is supplied to an iron compound crystallization device 4 (also referred to as an iron component analysis device). In the iron compound crystallization device 4 , the plating solution 10 is cooled to deposit the iron compound 11 (iron methanesulfonate in the case of a tin methanesulfonate plating solution). Iron methanesulfonate is a substance produced by the reaction of the steel strip with methanesulfonic acid, which is a component of the bath. In this iron compound crystallization device, the metal ions to be plated (ie, tin ions) remain dissolved in the plating solution 10 , and only the iron compound 11 is precipitated. Therefore, the cooling condition of the plating solution 10 in the iron compound crystallization device 4 is set to be in the middle of the temperature at which the iron compound is precipitated and the temperature at which the metal compound to be plated (ie, the tin compound) is precipitated. For example, in the case of a tin methanesulfonate plating solution, it is set at an intermediate temperature (about −4° C.) between the precipitation temperature of iron methanesulfonate and the precipitation temperature of tin methanesulfonate.

Next, the plating solution 10 and the iron compound 11 are supplied from the iron compound crystallization device 4 to the iron component separation device 5 . This iron component separation device 5 is composed of a separation device 6 for iron compounds and a redissolution device 7 for iron compounds, and is to remove the precipitated iron compound 11 (iron methanesulfonate in the case of tin methanesulfonate plating solution) from the plating solution 10 A device for separating and redissolving in water. As the iron compound separating device 6, conventionally known devices such as a filter and a centrifuge are used. However, considering that the sludge has been removed in this process, the viscosity of the mixture of the plating solution 10 and the iron compound 11 decreases, and the specific gravity of the iron compound 11 (ie, iron methanesulfonate) is relatively large, it is preferable to use a centrifuge.

The plating solution 10 from which the iron compound 11 has been separated by the iron compound separating device 6 is sent to the circulation tank 1 .

On the other hand, the iron compound 11 is supplied to the redissolving device 7 . The redissolving device 7 is a device for redissolving the iron compound 11 (that is, iron methanesulfonate) in water, and a water tank or the like in which water is stored is used. Here, water refers to water that does not contain methanesulfonic acid, such as distilled water, ion-exchanged water, tap water, and industrial water. In addition, the aqueous solution obtained by redissolving the iron compound 11 (that is, iron methanesulfonate) is referred to as the redissolved solution 12 below.

The redissolution liquid 12 is supplied from the redissolution device 7 to the iron ion removal device 8 (also referred to as an iron component removal device). The iron ion removal device 8 is a device for removing iron ions from the redissolution liquid 12 by adsorption onto an ion exchange resin by replacing the iron ions in the redissolution liquid 12 with protons. In the redissolving solution 12 from which iron ions have been removed, the plating solution component (ie, methanesulfonic acid) is regenerated, and this redissolving solution 12 is sent to the circulation tank 1 .

In this way, sludge and iron ions are removed from the used plating solution 10 accumulated in the circulation tank 1, and the regenerated plating solution 10 returns to the circulation tank 1 again, and further returns to the plating tank for recycling.

In addition, at least one of the group selected from the group consisting of the plating solution concentration device 3, the iron compound crystallization device 4, the iron compound separation device 6, the iron compound redissolution device 7, and the iron ion removal device 8 is selected for reasons such as failure and periodic inspection. When a device stops its operation, the valve 13b of the channel changing device 13 is opened and the valve 13a is closed. As a result, the plating solution 10 is sent from the sludge removal device 2 to the circulation tank 1 . That is, even when a series of devices related to the removal of iron components from the plating solution concentration device 3 to the iron ion removal device 8 or a part thereof are stopped, the sludge removed in the sludge removal device 2 can be removed. The plating solution 10 is transported to the circulation tank 1, so that the continuous operation of electroplating can be maintained.

Fig. 2 is a flowchart showing another example of the apparatus of the present invention. Specifically, the flow channel changing device 13 shown in FIG. 1 is installed on the discharge side (downstream) of the plating solution concentrating device 3 . Similar to the operation of FIG. 1 described above, when a series of apparatuses are operated, the valve 13b is closed and the valve 13a is opened.

However, at least one device selected from the group consisting of the iron compound crystallization device 4, the iron compound separation device 6, the iron compound redissolution device 7 and the iron ion removal device 8 stops its operation due to reasons such as failure and periodic inspection. , the valve 13b of the channel changing device 13 is opened, and the valve 13a is closed. As a result, the plating solution 10 is sent from the plating solution concentration device 3 to the circulation tank 1 . That is, even when a series of devices related to the removal of iron components or a part thereof from the iron compound crystallization device 4 to the iron ion removal device 8 are stopped, the plating solution removed in the sludge removal device 2 can be removed. The sludge in 10 and the plating solution 10 concentrated in the plating solution concentrating device 3 are sent to the circulation tank 1, thereby maintaining the continuous operation of electroplating.

Fig. 3 is a flowchart showing another example of the device of the present invention. Specifically, it is a device in which the flow channel changing device 13 of FIG. 1 is installed on the discharge side (downstream) of the iron compound crystallization device 4 . Similar to the operation of FIG. 1 described above, when a series of apparatuses are operated, the valve 13b is closed and the valve 13a is opened.

However, when at least one device selected from the group consisting of the iron compound separation device 6, the iron compound redissolution device 7 and the iron ion removal device 8 is stopped due to failure and periodic inspection, the plating solution The valve 13b of the channel changing device 13 is opened, and the valve 13a is closed. As a result, the plating solution 10 is transferred from the iron compound crystallization device 4 to the circulation tank 1 . That is, even when a series of devices related to the removal of iron compounds from the iron compound separation device 6 to the iron ion removal device 8 or a part thereof are stopped, the plating solution removed in the sludge removal device 2 can be removed. The sludge in 10, the plating solution 10 concentrated in the plating solution concentration device 3, and then the iron compound is precipitated in the iron compound crystallization device 4 is sent to the circulation tank 1, thereby maintaining the continuous operation of electroplating. In this case, although the iron compound precipitates are mixed into the plating solution in the circulation tank 1, they are dissolved in the circulation tank 1, so that they do not interfere with the plating operation.

As described above, the present invention is a plating solution regeneration device for electroplating, an operation method of the device, and a regeneration method of the plating solution. In the plating solution regeneration device for electroplating, the sludge removal device 2 and the plating At least one of the groups formed between the liquid concentration device 3, between the plating solution concentration device 3 and the iron compound crystallization device 4, and between the iron compound crystallization device 4 and the iron compound separation device 6 has a connection to the The channel changing device 13 of the circulation tank.

Therefore, the following devices are of course also included in the technical scope of the plating solution regeneration device of the present invention: the device of three flow channel changing devices 13 is preset in all the above-mentioned three places, or any two places in the above-mentioned three places are selected and A device in which two flow path changing devices 13 are provided in advance. The plating solution can be regenerated by using these devices and appropriately switching the valves of the channel changing device 13 suitable for a desired operation method.

Moreover, in any one of the above-mentioned plating solution regenerating devices of the present invention, preferably between the iron compound redissolving device 7 and the iron ion removing device 8, there is further a change in the flow path of the redissolving solution connected to the circulation tank. device 14.

That is, it is preferable to install the valves 14a and 14b of the flow channel changing device 14 for the redissolving liquid and the piping connected to the circulation tank on the discharge side (downstream) of the redissolving device 7 .

An example of such an arrangement is shown in FIG. 3 . When the iron ion removal device 8 is operating, the valve 14b is closed and the valve 14a is opened. Therefore, usually, the redissolving solution 12 is supplied from the redissolving device 7 to the iron ion removing device 8 .

On the other hand, when the operation of the iron ion removing device 8 is stopped due to equipment failure, periodic inspection, etc., the valve 14b of the flow path changing device 14 for the redissolving solution is opened and the valve 14a is closed. As a result, the redissolving solution 12 is sent from the redissolving device 7 to the circulation tank 1 . That is, even when the operation of the iron ion removing device 8 is stopped, the sludge obtained by removing the sludge in the plating solution 10 in the sludge removing device 2, precipitating the iron compound, and dissolving the iron compound in water can be recovered. The solution 12 is sent to the circulation tank 1, whereby continuous operation of electroplating can be maintained.

Although an example is shown in which valves 14a, 14b are provided as components of the redissolved liquid flow path changing device 14 used in the present invention, the flow path changing device 14 used in the present invention is not limited to valves, and conventionally used A device that changes the fluid flow path (such as a valve opening and closing device, etc.).

In any of the plating solution regenerating devices of the present invention, one of the plating solution channel changing device 13 and the redissolving solution channel changing device 14 may be used, or both may be used in combination.

In addition, the above description shows only an example of the embodiment of the present invention in the case of the tin methanesulfonate plating solution, and various changes can be made according to the type of metal to be plated and the components of the plating solution.

As described above, according to the present invention, sludge and iron components can be removed from the plating solution used for electroplating to regenerate the plating solution. Furthermore, in this plating solution regeneration device, even when the operation of the device related to the removal of iron components is stopped, the continuous operation of electroplating can be maintained without reducing the operating rate of the sludge removal device. Thereby, productivity improvement of a galvanized steel strip can be aimed at.

Example 1

The plating solution used in the plating tank installed on the tinplate strip production line is sent to the circulation tank. The plating solution is tin methanesulfonate plating solution. Along with the manufacture of tinplate steel strip, sludge, iron ions and tin ions are inevitably mixed into the plating solution. The plating solution was regenerated using the apparatus shown in Flowchart 1 .

As shown in FIG. 1 , a plating solution 10 is supplied from a circulation tank 1 to a sludge removing device 2 to remove sludge. The sludge removal device 2 uses a filter press. In normal operation, the valve 13b of the channel changing device 13 arranged on the discharge side of the sludge removal device 2 is closed, and the valve 13a is opened, so that the plating solution 10 is supplied from the sludge removal device 2 to the plating solution. Concentrator 3. In the plating solution concentration device 3 , the plating solution 10 is distilled under reduced pressure to vaporize water, and concentrated to four times the methanesulfonic acid concentration of the plating solution 10 supplied from the sludge removal device 2 . The plating solution 10 concentrated in the plating solution concentration device 3 was supplied to the iron compound crystallization device 4 and cooled to -4°C to precipitate iron methanesulfonate. Next, the plating solution 10 and the precipitate are supplied to the iron compound separator 6 in the iron component separator 5 . The iron methanesulfonate precipitated in the iron compound separating device 6 is separated from the plating solution 10 . As the iron compound separator 6, a centrifuge or the like is used. The plating solution 10 that has separated iron methanesulfonate 11 in the iron compound separating device 6 is sent to the circulation tank 1, on the other hand, the iron methanesulfonate 11 is supplied to the iron compound redissolving device 7, and the iron methanesulfonate 11 Dissolved in industrial water. The obtained redissolved solution 12 is supplied to the iron ion removal device 8 so that iron ions are adsorbed on the ion exchange resin. The redissolved solution 12 from which iron ions have been removed is sent to the circulation tank 1 .

In addition, when at least one device of the plating solution concentration device 3, the iron compound crystallization device 4, the iron compound separation device 6, the iron compound redissolution device 7, and the iron ion removal device 8 is stopped, the flow path changing device 13 is turned off. The valve 13b is opened, and the valve 13a is closed, thereby transferring the plating solution 10 from the sludge removal device 2 to the circulation tank 1 . Let this be an invention example.

On the other hand, as a comparative example, the used plating solution was regenerated by the apparatus shown in Flowchart 4 . This device is the same as the usual operation of the inventive example, so description is omitted. However, when at least one of the plating solution concentration device 3, the iron compound crystallization device 4, the iron compound separation device 6, the iron compound redissolving device 7, and the iron ion removal device 8 is stopped, the regeneration process of the entire plating solution 10 stop.

For the inventive example and the comparative example, the tinplate strip production line was operated for twelve months, and the operation rate of the sludge removal device 2 was investigated. During this twelve-month period, circumstances arose that had to shut down the equipment related to the removal of iron components.

As a result, the operating rate of the sludge removal device 2 was 100% in the example of the invention, whereas it was 50% in the comparative example. Therefore, compared with the comparative example, the productivity of the tinplate strip improved in the inventive example.

Example 2

The plating solution used in the plating tank installed on the tinplate strip production line is sent to the circulation tank. The plating solution is tin methanesulfonate plating solution. Along with the manufacture of tinplate steel strip, sludge, iron ions and tin ions are inevitably mixed into the plating solution. The bath was regenerated using the apparatus shown in Flowchart 2.

As shown in FIG. 2 , a plating solution 10 is supplied from a circulation tank 1 to a sludge removing device 2 to remove sludge. The sludge removal device 2 uses a filter press. The plating solution 10 from which the sludge has been removed is supplied to the plating solution concentrating device 3 . In the plating solution concentrating device 3 , the plating solution 10 is distilled under reduced pressure to vaporize water, and concentrated to four times the methanesulfonic acid concentration of the plating solution 10 supplied from the sludge removing device 2 . In a normal operation, the valve 13b of the flow channel changing device 13 arranged on the discharge side of the plating solution concentrating device 3 is closed, and the valve 13a is opened to supply the plating solution 10 from the plating solution concentrating device 3 to the iron compound. Crystallization device 4. The concentrated plating solution 10 was supplied to the iron compound crystallization device 4 and cooled to -4°C to precipitate iron methanesulfonate. Next, the plating solution 10 and the precipitate are supplied to the iron compound separator 6 in the iron component separator 5 . The iron methanesulfonate precipitated in the iron compound separating device 6 is separated from the plating solution 10 . As the iron compound separator 6, a centrifuge or the like is used. The plating solution 10 that has separated iron methanesulfonate 11 in the iron compound separating device 6 is sent to the circulation tank 1, on the other hand, the iron methanesulfonate 11 is supplied to the iron compound redissolving device 7, and the iron methanesulfonate 11 Dissolved in industrial water. The obtained redissolved solution 12 is supplied to the iron ion removal device 8 so that iron ions are adsorbed on the ion exchange resin. The redissolved solution 12 from which iron ions have been removed is sent to the circulation tank 1 .

In addition, when at least one of the iron compound crystallization device 4, the iron compound separation device 6, the iron compound redissolution device 7, and the iron ion removal device 8 is stopped, the valve 13b of the flow channel changing device 13 is opened, and the The valve 13a is closed, so that the plating solution 10 is delivered from the plating solution concentrating device 3 to the circulation tank 1 . Let this be an invention example.

On the other hand, as a comparative example, the used plating solution was regenerated by the apparatus shown in Flowchart 4 . This device is the same as the usual operation of the inventive example, so description is omitted. However, when at least one of the iron compound crystallization device 4, the iron compound separation device 6, the iron compound redissolution device 7, and the iron ion removal device 8 is stopped, the regeneration process of the entire plating solution 10 is stopped.

For the inventive example and the comparative example, the tinplate strip production line was operated for twelve months, and the operation rate of the sludge removal device 2 was investigated. During this twelve-month period, circumstances arose that had to shut down the equipment related to the removal of iron components.

As a result, the operating rate of the sludge removal device 2 was 100% in the inventive example, whereas it was 50% in the comparative example. In addition, the operating rate of the plating solution concentrating device 3 was 95% in the inventive example, whereas it was 45% in the comparative example. Therefore, compared with the comparative example, the productivity of the tinplate strip improved in the inventive example.

Example 3

The plating solution used in the plating tank installed on the tinplate strip production line is sent to the circulation tank. The plating solution is tin methanesulfonate plating solution. Along with the manufacture of tinplate steel strip, sludge, iron ions and tin ions are inevitably mixed into the plating solution. The plating solution was regenerated using the apparatus shown in Flowchart 3 .

As shown in FIG. 3 , a plating solution 10 is supplied from a circulation tank 1 to a sludge removing device 2 to remove sludge. The sludge removal device 2 uses a filter press. The plating solution 10 from which the sludge has been removed is supplied to the plating solution concentrating device 3 . In the plating solution concentrating device 3 , the plating solution 10 is distilled under reduced pressure to vaporize water, and concentrated to four times the methanesulfonic acid concentration of the plating solution 10 supplied from the sludge removing device 2 . The plating solution 10 concentrated in the plating solution concentration device 3 was supplied to the iron compound crystallization device 4 and cooled to -4°C to precipitate iron methanesulfonate. Next, in normal operation, the valve 13b of the channel changing device 13 provided on the discharge side of the iron compound crystallization device 4 is closed, and the valve 13a is opened to supply the plating solution 10 and the deposit to the iron component separation process. The iron compound separation device 6 in the device 5. The iron methanesulfonate precipitated in the iron compound separating device 6 is separated from the plating solution 10 . As the iron compound separator 6, a centrifuge or the like is used. The plating solution 10 that has separated iron methanesulfonate 11 in the iron compound separating device 6 is sent to the circulation tank 1, on the other hand, the iron methanesulfonate 11 is supplied to the iron compound redissolving device 7, and the iron methanesulfonate 11 Dissolved in industrial water. In normal operation, the valve 14b of the redissolved liquid flow channel changing device 14 on the discharge side of the iron compound redissolved device 7 arranged in the iron component separating device 5 is closed, and the valve 14a is opened, thereby redissolving The liquid 12 is supplied from the iron compound redissolving device 7 to the iron ion removal device 8 . In the iron ion removal device 8 , iron ions are adsorbed on the ion exchange resin. The redissolved solution 12 from which iron ions have been removed is sent to the circulation tank 1 .

In addition, when at least one of the iron compound separating device 6, the iron compound redissolving device 7, and the iron ion removing device 8 is stopped, the valve 13b of the flow path changing device 13 is opened, and the valve 13a is closed, so that the The plating solution 10 is delivered to the circulation tank 1 from the iron compound crystallization device. In particular, when only the iron ion removal device 8 is stopped, the valve 13b of the channel changing device 13 is closed, and the valve 13a is opened, and at the same time, the valve 14b of the channel changing device 14 for the redissolving solution is opened, and By closing the valve 14a, the redissolution solution 12 is sent from the iron compound redissolution device 7 to the circulation tank 1 . Let this be an invention example.

On the other hand, as a comparative example, the same spent plating solution as that of the inventive example was regenerated by using the apparatus shown in Flowchart 4 . This device is the same as the usual operation of the inventive example, so description is omitted. However, when at least one of the iron compound separating device 6 , the iron compound redissolving device 7 , and the iron ion removing device 8 is stopped, the regeneration treatment of the entire plating solution 10 is stopped.

For the inventive example and the comparative example, the tinplate strip production line was operated for twelve months, and the operating rates of the sludge removal device 2 and the iron compound crystallization device 4 were investigated. During this twelve-month period, circumstances arose that had to shut down the equipment related to the removal of iron components.

As a result, the operating rate of the sludge removal device 2 was 100% in the inventive example, whereas it was 50% in the comparative example. In addition, the operating rate of the iron compound crystallization device 4 was 90% in the inventive example, whereas it was 40% in the comparative example. Therefore, compared with the comparative example, the productivity of the tinplate strip improved in the inventive example.

Industrial Utilization Possibility

According to the apparatus and method of the present invention, sludge and iron components can be removed from the plating solution used for electroplating a steel strip to regenerate the plating solution. Furthermore, the apparatus of the present invention can maintain the continuous operation of electroplating without reducing the operating rate of the sludge removal apparatus even when the apparatus related to the removal of iron components is stopped. Thereby, productivity improvement of a plated steel strip can be aimed at, and it can make a wide contribution to industry.

Claims (12)

1. A plating solution regeneration device for electroplating, which has: circulation tank, Sludge removal device, concentration device, Crystallization device for iron compounds, Separation device for iron compounds, redissolving device for iron compounds, Iron ion removal device, Take the circulation tank as the base point and connect the pipes of these devices in the downstream direction in the above order, The pipeline connected to the circulation tank by the iron ion removal device, a pipe connected to the circulation tank by the separation device of the iron compound, and At least one selected from the group consisting of between the sludge removal device and the concentration device, between the concentration device and the iron compound crystallization device, and between the iron compound crystallization device and the iron compound separation device is connected to The flow path changing device of the circulation tank. 2. The plating solution regenerating device according to claim 1, wherein the channel changing device is disposed between the sludge removing device and the concentrating device. 3. The plating solution regenerating device as claimed in claim 1, wherein the channel changing device is disposed between the concentrating device and the iron compound crystallizing device. 4. The plating solution regenerating device as claimed in claim 1, wherein the channel changing device is disposed between the iron compound crystallization device and the iron compound separation device. 5. The plating solution regenerating device according to any one of claims 1 to 4, further comprising a channel changing device connected to the circulation tank between the iron compound redissolving device and the iron ion removing device. 6. A plating solution regenerating device for reusing a used plating solution for electroplating a steel strip, characterized in that it has a circulation tank for accumulating the plating solution, and all the components supplied by the circulation tank are provided. A sludge removing device for removing sludge in the plating solution, a plating solution concentrating device for concentrating the plating solution supplied from the sludge removing device, cooling the plating solution supplied from the plating solution concentrating device and An iron component separating device for precipitating an iron compound, an iron component separating device for separating the iron compound from the plating solution supplied from the iron component separating device and redissolving it in water, an ion exchange resin The iron component removal device for removing iron ions from the redissolved solution supplied by the iron component separation device has a flow channel changing device for feeding the plating solution from the plating solution concentrating device to the circulation tank. 7. The operating method of the plating solution regenerating device as claimed in claim 1, wherein, after making the device selected from the concentration device, the iron compound crystallization device, the iron compound separation device, the iron compound redissolving device and the iron ion removal When at least one device in the group consisting of devices is stopped, further upstream of the stop device that is the most upstream, and selected from between the sludge removal device and the concentration device, the concentration device and the iron compound crystallization device At least one of the groups formed between the iron compound crystallization device and the iron compound separation device switches the flow channel of the plating solution to the circulation tank. 8. The operation method of the plating solution regenerating device as claimed in claim 1, wherein, in the group selected from the group consisting of the iron compound crystallization device, the iron compound separation device, the iron compound redissolving device and the iron ion removal device When at least one of the devices is stopped, at the upstream of the most upstream stop device, and between the sludge removal device and the concentration device, between the concentration device and the iron compound crystallization device and the At least one of the groups formed between the iron compound crystallization device and the iron compound separation device switches the flow channel of the plating solution to the circulation tank. 9. The operation method of the plating solution regeneration device as claimed in claim 1, wherein at least one device selected from the group consisting of the iron compound separation device, the iron compound redissolving device and the iron ion removal device When stopping, further upstream of the most upstream stop device, and between the sludge removal device and the concentration device, between the concentration device and the iron compound crystallization device, and between the iron compound crystallization device and the iron compound crystallization device At least one of the groups of iron compound separating devices switches the flow path of the plating solution to the circulation tank. 10. The operation method of the plating solution regenerating device as claimed in claims 7 to 9, wherein, when the iron ion removing device is stopped, the redissolving device is further redissolved between the iron compound redissolving device and the iron ion removing device. The flow channel of the solution is switched to this circulation tank. 11. The operation method of the plating solution regeneration device according to claims 7-9, wherein the plating solution is an electroplating solution containing tin methanesulfonate. 12. A method for regenerating a plating solution for reusing a used plating solution for electroplating a steel strip, wherein the plating solution accumulated in a circulation tank is supplied to a sludge removal device to After removing the sludge in the plating solution, the plating solution is supplied to a plating solution concentrating device to concentrate the plating solution, and then the plating solution is supplied to an iron component separating device to make the plating solution in the plating solution Iron is precipitated in the form of an iron compound, and the plating solution is further supplied to an iron component separation device to separate the iron compound, and the separated iron compound is redissolved in water to form a redissolving solution, and the redissolved The solution is supplied to the iron component removal device and iron ions are removed by an ion exchange resin, and at the same time, the plating solution from which the iron compound is removed in the iron component removal device and the iron component removal device are removed. The redissolved solution of the iron ions is sent to the circulation tank. On the other hand, when the iron component separating device, the iron component separating device, or the iron component removing device is stopped, the The plating solution concentration device delivers the plating solution to the circulation tank.

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