JP7601893B2 - Metal recovery equipment status monitoring system - Google Patents

Description

The present invention relates to a system for monitoring the status of a metal recovery device.

Valuable metals such as Au, Ag, Pt, Ni, Cu, and Co are contained in various waste liquids, such as processing liquids discharged from factories and solutions obtained by dissolving waste materials. Metals to be recovered are recovered, for example, by electrolyzing the waste liquid. Various metal recovery devices using electrolysis have been used in the past, such as those shown in Patent Documents 1 to 4.

As metal recovery equipment operates for long periods of time, the electrodes deteriorate, reducing its operating efficiency, and the wiring and equipment also deteriorate, requiring maintenance. However, the timing at which maintenance is required for the metal recovery equipment varies depending on factors such as the type of electrolyte and processing conditions, making it difficult to predict when maintenance will be required for the metal recovery equipment. As a result, the condition of the metal recovery equipment is checked regularly, but this requires the equipment to be stopped, which reduces the metal recovery efficiency and creates a significant workload.

JP 2017-155343 A International Publication No. WO 2008/153001 JP 2007-002310 A Japanese Unexamined Patent Publication No. 61-104096

The present invention has been developed in consideration of the above problems, and aims to provide a system for monitoring the status of a metal recovery device.

The condition monitoring system of the present invention, which has been able to solve the above problems, has the following configuration.
[1] A system for monitoring the status of a metal recovery device, comprising:
The condition monitoring system includes:
A metal recovery device and a control device are provided,
The metal recovery device comprises:
A voltage measuring unit for measuring a voltage between the cathode and the anode is provided.
The control device includes:
a data calculation unit that processes the voltage data received from the voltage measurement unit;
The data calculation unit calculates a first-order differential value or a second-order differential value as a feature amount based on the voltage data, and
The characteristic amount is compared with a predetermined threshold value, and when the characteristic amount is equal to or greater than the threshold value, the metal recovery device is diagnosed as requiring maintenance.

[2] It is also a preferred embodiment that the control device notifies the management terminal via a telecommunications line of the diagnostic results obtained by comparing with a threshold value.

[3] It is also a preferred embodiment that the subject of the maintenance-requiring condition is an anode coated with an electrode catalyst.

The present invention provides a system for monitoring the status of a metal recovery device. In particular, the system of the present invention monitors the voltage of the metal recovery device, making it possible to grasp the status of the metal recovery device and perform maintenance on the metal recovery device at the appropriate time.

FIG. 1 is a schematic diagram showing the overall configuration of a monitoring system for a metal recovery apparatus according to the present invention. FIG. 2 is a schematic diagram of the metal recovery device. FIG. 3 is a block diagram showing the configuration of a monitoring system according to an embodiment of the present invention. FIG. 4 shows an example of the database configuration. FIG. 5 is a flowchart showing an example of data processing. FIG. 6 is a graph plotting first-order differential values based on voltage data. FIG. 7 is a graph plotting values obtained by second-order differentiation based on voltage data.

[Overall configuration of surveillance system]
FIG. 1 is a schematic diagram showing an example of the overall configuration of a state monitoring system for a metal recovery apparatus (hereinafter referred to as a state monitoring system) of the present invention.
The status monitoring system of the present invention monitors the voltage status used in the metal recovery device 1. The status monitoring system includes the metal recovery device 1 and a control device 20.
The metal recovery device 1 has an anode and a voltage measuring unit 10 that measures the voltage between the anode and the cathode.
The control device 20 has a data calculation unit that processes the voltage data received from the voltage measurement unit 10 .
The control device 20 is equipped with a data calculation unit which is a central processing unit represented by a CPU, a storage unit for various data, and a data input/output unit, and is, for example, a processor such as a CPU, a memory such as a ROM, a storage medium such as a HDD, a general-purpose computer equipped with a communication function for transmitting and receiving data, or an electronic calculator such as a personal computer or a server.
The control device 20 is connected by wire or wirelessly to the output section of the voltage measurement section 10 provided in the metal recovery device 1, and is configured to be able to acquire voltage data when the metal recovery device is in operation.
Furthermore, the status monitoring system may optionally include a management terminal 40. The results of processing the voltage data in the data processing section of the control device 20 may be notified to the management terminal 40 via an electric communication line as necessary.

[Configuration of metal recovery device]
Fig. 2 is a schematic diagram showing an example of the metal recovery apparatus 1. The outline of the metal recovery apparatus 1 will be described based on Fig. 2, but the present invention is not limited to the illustrated example, and the system of the present invention can be applied to various known metal recovery apparatuses that recover metals from waste liquid by utilizing electrolysis.
The condition monitoring system of the present invention can be used without modifying the configuration of an existing metal recovery device.
The metal recovery device 1 has an electrolytic cell 2 which contains waste liquid 6 containing metal ions (hereinafter referred to as a metal ion-containing solution), and an anode 3 and a cathode 4 which are necessary for electrolysis.
The size, shape, and material of the electrolytic cell 2 can be appropriately selected depending on the purpose.
The anode 3 is an insoluble material. Various known electrode base materials can be used for the anode 3, and metals having corrosion resistance, such as titanium, niobium, zirconium, and various alloys using these as base materials, are preferred. In addition, the metal recovery device of the present invention preferably uses an anode in which the electrode base material is coated with an electrode catalyst. Examples of the electrode catalyst that coats the anode base material include oxides of platinum group metals such as ruthenium, rhodium, palladium, platinum, and iridium.
The present invention can be applied to the anodes of existing metal recovery devices, and therefore can be applied without changing the size, shape, number, or material of the anodes.

The material of the cathode 4 can be appropriately selected depending on the type of metal ion-containing solution 6 and the metal to be recovered, and may be, for example, iron, nickel, stainless steel, aluminum, titanium, or an alloy having these as a base material.
In the illustrated example, a cylindrical cathode 4 is used, but since the present invention can be applied to existing metal recovery devices, it can be applied without changing the material, size, shape, structure, etc. of the cathode.
The cathode 4 is provided with a drive unit 5, and is configured to rotate the cathode 4 by the drive unit 5. The cathode 4 rotates in the circumferential direction about an axis 14 by the operation of the drive unit 5. An example of the drive unit 5 is a power source such as a motor, but is not limited to this.

The anode 3 and the cathode 4 are connected to a power supply unit 7 having a rectifier and an AC power supply, and are configured so that a potential is generated between the anode 3 and the cathode 4 in the electrolytic cell 2 .
The power supply unit 7 rectifies the AC power supply and supplies a predetermined DC current to the electrodes 3 and 4. When power is supplied, electrolysis of the metal ion-containing solution 6 is carried out in the electrolytic cell 2, and valuable metals are deposited on the cathode 4.
In the present invention, in order to measure the voltage of the current supplied to the electrodes, a voltage measurement unit 10 is installed in the metal recovery device 1. The voltage measurement unit 10 has a voltage measurement sensor 8 such as a voltmeter, a voltage measurement terminal 9, and a measurement value output unit 11. The voltage measurement terminal 9 is connected to any position between the power supply unit 7 and the anode 3 and between the power supply unit 7 and the cathode 4 so that the voltage of the electrodes can be measured.

There is no particular limitation on the metal ion-containing solution 6 as long as it is a solution that contains valuable metals. Examples of the metal ion-containing solution 6 include plating waste liquids such as plating stripping solutions, plating solutions, and cleaning solutions for plated products, and solutions in which materials containing valuable metals, such as printed circuit boards, are dissolved in an acidic solution.
Valuable metals include, but are not limited to, gold, silver, copper, nickel, platinum group elements, and the like, and may be any metal that is eligible for recovery.

The metal ion-containing solution 6 is supplied from a discharge source such as a factory through a supply tank 12 provided as necessary, or from a supply port provided in the electrolytic cell 2 to the electrolytic cell 2 in a batch or continuous manner. A liquid delivery means such as a pump 13 may be used to supply the metal ion-containing solution 6 as necessary. The operating conditions of the metal recovery device, such as the electrolysis conditions, are set appropriately depending on the processing volume of the metal recovery device 1 and the supply amount of the metal ion-containing solution 6. The present invention can employ the operating conditions of the existing metal recovery device 1.
After being treated in the electrolytic cell 2, the treated liquid is sent to an arbitrary treatment step. In the illustrated example, the treated liquid discharged from the electrolytic cell 2 is returned to the supply cell 12 and is supplied to the electrolytic cell 2 again. In the present invention, the treatment step of the treated liquid is not particularly limited, and a known process can be used. For example, the treated liquid may be sent to an arbitrary treatment step other than electrolysis.

In this specification, the voltage fluctuates due to the depletion of the electrode catalyst coated on the anode, but the status monitoring system of the present invention is not limited to voltage fluctuations due to the anode. The status monitoring system of the present invention can also include accelerated voltage fluctuations caused by various failures. For example, if the wiring connecting the electrode and the power supply unit deteriorates, the voltage may fluctuate at an accelerated rate when an abnormality occurs in the metal recovery device. In such a case, if the characteristic amount exceeds the threshold value, a notification is sent to the management terminal 40. This notification indicates that the metal recovery device is in a state requiring maintenance. If the state of the anode confirmed based on this notification is normal, it can be determined that there is a problem in another part, such as the wiring. Therefore, based on the notification, it can be determined that the metal recovery device is in a state requiring maintenance.

[Relationship between voltage change and anode deterioration]
In a metal recovery device, for example, when an anode is used in which an electrode substrate is coated with an electrocatalyst such as a precious metal, the performance of the anode deteriorates as the electrolysis period becomes longer, and the electrolysis efficiency decreases, requiring maintenance of the anode.
As a result of research by the inventors, it was found that the appropriate time for maintenance of the anode can be determined by measuring the voltage of the current supplied to the electrode and comparing a feature calculated from the measured value with a threshold value (hereinafter referred to as the threshold value) for determining the deterioration state of the anode.
Through extensive research, the inventors have found that when the electrolytic process involves the wear of the electrode catalyst coated on the anode, resulting in a decrease in the area of the coated electrode catalyst, current is concentrated in the remaining electrode catalyst portion, accelerating the wear of the electrode catalyst and causing a sudden increase in voltage.
If the voltage during electrolysis is measured and the values are plotted on a graph, the voltage will rise as the anode electrode catalyst wears away and the anode begins to deteriorate, resulting in an inflection point where the voltage curve changes. However, even if the amount of voltage change per unit time is observed, the voltage also changes depending on the treatment conditions such as the type of solution being treated and the metal ion concentration, so if the voltage change is detected as the object of detection, there will be many detection errors and it will be difficult to determine whether maintenance is required.

As a result of further investigation into reducing detection errors, it was found that when the voltage measurement results are differentiated by the first or second order and plotted, an inflection point appears where the voltage curve steeply changes from 0 to a positive value, as shown in Figures 6 and 7 (indicated by the arrow in the figures), and that when this first or second order differential value is equal to or greater than a predetermined threshold value, it can be determined that anode maintenance is necessary.
Therefore, in the present invention, the measured voltage data (raw data) is not used as is, but the first or second derivative (hereinafter, these may be collectively referred to as the derivative value) is used as a feature, and this feature is compared with a threshold value to determine whether or not maintenance of the anode is required.
The first-order differentiation method may be, but is not limited to, for example, dividing the amount of change in voltage by time, and the second-order differentiation method may be, but is not limited to, for example, dividing the amount of change in the first-order differential value by time.

The threshold value can be determined by referring to the values when anode maintenance is required, based on electrolysis conditions such as the type of electrolysis solution, voltage, and current, past data, and data from similar devices.
An arbitrary voltage may be set as the threshold, and a maintenance-required state may be determined when the feature value reaches the threshold, but the voltage may fluctuate significantly after the start of operation, which may result in erroneous detection. From the viewpoint of reducing the rate of erroneous detection that occurs in the early stages of operation, for example, (1) an average value of differential values may be calculated a predetermined time after the start of electrolysis, twice the average value may be set as a threshold value, differential values sampled at predetermined intervals may be compared with the threshold value, and a maintenance-required state may be determined when the differential value is equal to or greater than the threshold value once or any number of times greater than or equal to two.
Alternatively, (2) a differential value calculated a predetermined time after the start of electrolysis is compared with a moving average value of each differential value, and when the moving average value becomes equal to or greater than the threshold value, it may be determined that maintenance is required.
The differential value is calculated after a predetermined time has elapsed because the voltage is likely to increase or decrease immediately after the start of electrolysis, and it is therefore desirable to collect data after the voltage has stabilized, for example, 30 hours after the start of electrolysis.
In addition, it is desirable to compare the differential value with the threshold value at regular intervals, and for example, when the electrolytic device is operated continuously for 24 hours, the comparison may be performed at regular intervals such as every 12 hours or every 24 hours, or at any interval (hereinafter, collectively referred to as a "predetermined interval"). When the operation of the electrolytic device is less than 24 hours, the comparison may be performed at the predetermined interval during the operation.
The moving average value may be calculated for any fixed interval, for example, every 100 hours.

In addition, (3) it is also a preferred embodiment to set the threshold value as follows:
The feature quantity is calculated from the acquired voltage data, and the average value and standard deviation (1σ) of the feature quantity are calculated, and the average value + nσ (n is an arbitrarily set value) is set as a threshold value. The feature quantity is compared with this threshold value, and if the feature quantity is equal to or greater than the threshold value, it is determined that maintenance is required.
For example, in Table 1, the state of the anode can be monitored by setting the threshold values as follows: Table 1 shows data corresponding to FIG.

In Table 1, the threshold value is set to the average value + 3σ, and it can be determined that maintenance is required when the accumulated time that the feature exceeds the threshold value is 129 hours.

[Configuration of the status monitoring system]
FIG. 3 is a block diagram showing the configuration of a status monitoring system according to an embodiment of the present invention.
The control device 20 has a data acquisition unit 22, a storage unit 23, a data calculation unit 24, and an output unit 25. The control device 20 preferably further has an A/D converter 21 that converts the voltage data acquired by the voltage measurement unit 10 into digital data.

Figure 5 is a flowchart showing an example of processing by the data calculation unit 24 of the control system 20.

While the metal recovery device 1 is in operation, the voltage measurement unit 10 measures the voltage of the current supplied to the electrode using the voltage measurement sensor 8. The measurement interval in the voltage measurement sensor 8 can be set arbitrarily, and may be set to measure the voltage at regular intervals or continuously, for example. The obtained voltage data (voltage measurement value) is transmitted to the control device 20 via the measurement value output unit 11. The voltage data is preferably transmitted to an A/D converter 21. The measurement value output unit 11 and the control device 20 are connected by any communication means such as a wired LAN, wireless LAN, WiFi, a telecommunications line such as a telephone communication line, or a data transfer cable, and are configured to be able to transmit voltage data.

The A/D converter 21 converts the analog signal received from the voltage measurement unit 10 into a digital signal.

The data acquisition unit 22 receives voltage data from the voltage measurement unit 10 or the A/D converter 21. The received voltage data is stored in the memory unit 23 and transmitted to the data calculation unit 24. The received voltage data may be transmitted directly from the data acquisition unit 22 to the data calculation unit 24, or may be stored from the data acquisition unit 22 in the memory unit 23 and then read out from the memory unit 23 and transmitted to the data calculation unit 24. It is preferable to store the voltage data in association with acquisition time information.

The data calculation unit 24 calculates the feature quantity (first-order differential and/or second-order differential value) from the acquired voltage data. The obtained differential value is stored in the memory unit 23 as the feature quantity.

The data calculation unit 24 also compares the feature amount with a threshold value to determine the state of the anode. The determination result is stored in the memory unit 23. The determination result may be stored in the memory unit 23 with additional information such as symbols, numbers, and characters. Examples of additional information include information that distinguishes between values above the threshold value and values below the threshold value, and the difference between the feature amount and the threshold value.

The data calculation unit 24 determines whether an event such as a notification is necessary depending on the judgment result, and transmits the judgment result from the output unit 25 to the management terminal 40 as necessary. For example, when the judgment result meets a necessary condition, such as being equal to or greater than a threshold value, this triggers the execution of an event, and the output unit 25 notifies the management terminal 40 via a telecommunications line. The notification content can be information set appropriately, such as a predetermined judgment result, various acquired data, or a fixed phrase. For example, the notification information may be generated by adding a fixed phrase prepared in advance in the memory unit 23 to the judgment result, voltage data, etc.

The output unit 25 communicates with the management terminal 40 via a communication line. For example, when the output unit 25 receives a judgment result from the data calculation unit 24, it transmits the information to the management terminal 40. The information and date and time transmitted to the management terminal 40 may be stored in the memory unit 23.

Various processes in each processing unit of the control device 20, such as the data acquisition unit 22, the storage unit 23, the data calculation unit 24, and the output unit 25, are realized by a processor such as a CPU executing a program corresponding to each process. Each program is pre-stored in a memory such as a ROM, and the processor reads and executes the program from the memory, thereby executing and operating the required process in each processing unit.
A recording medium such as a RAM for temporarily storing data may be provided as necessary. By temporarily storing data in the RAM, the time required for the processor to retrieve data from a storage medium such as a HDD can be reduced.

The storage unit 23 may be a built-in storage medium such as an HDD or SSD, or a portable storage medium such as an SD card or a USB memory.
In the present invention, it is preferable to provide a database (DBMS: database management system) area in the storage unit 23 and input and store each data received by the storage unit 23 in an appropriate record of the database. For example, in the database of Fig. 4, it is preferable to create records for storing data generated in the above process, such as a unique primary key, a measurement date record (Day), a measurement time record (Time), an integrated time record, a current data record, a voltage data record, a second-order differential record, an average value record, a standard deviation record, a threshold value record, and a judgment result record, and to link each data derived from the same voltage data to the same primary key and input and store it in each record. If necessary, the database may be provided with records holding any information, such as a status indicated by the above data, or an event or action triggered by the above data.

The output unit 25 is a functional unit that communicates between the control device 20 and an external management terminal 40, and is composed of a communication module that can be connected to a telecommunications line such as an LTE line or the Internet, or a communication module that can be connected to a wired LAN, for example.

The management terminal 40 to be notified may be one or more. The management terminal 40 is a terminal capable of communicating with the control device 20, and examples of the management terminal 40 include mobile information terminals such as smartphones, tablets, PDAs, and mobile phones, as well as terminals equipped with various communication modules such as mobile computers and desktop computers.

The administrator can grasp the state of the anode 3 based on the notification received at the management terminal 40, and can carry out appropriate maintenance and management, such as replacing the anode.
The administrator can access the control device 20 through an electric communication line, or can check the data stored in the memory unit 23 through a terminal such as a personal computer optionally connected to the control device 20. In this case, the state of the anode can be easily checked by using a program that extracts and processes any record or data from the database. For example, the voltage information may be used to graph the change in voltage over time so that it can be monitored.

This application claims the benefit of priority based on Japanese Patent Application No. 2020-176849, filed on October 21, 2020. The entire contents of the specification of Japanese Patent Application No. 2020-176849, filed on October 21, 2020, are incorporated by reference into this application.

REFERENCE SIGNS LIST 1 Metal recovery device 2 Electrolytic cell 3 Anode 4 Cathode 5 Drive unit 6 Metal ion-containing solution 7 Power supply unit 8 Voltage measurement sensor 9 Voltage measurement terminal 10 Voltage measurement unit 11 Measurement value output unit 12 Supply tank 13 Pump 14 Shaft 20 Control device 21 A/D converter 22 Data acquisition unit 23 Memory unit 24 Data calculation unit 25 Output unit 40 Management terminal

Claims (3)

1. A system for monitoring the condition of an anode in a metal recovery device, comprising:
The condition monitoring system includes:
A metal recovery device and a control device are provided,
The metal recovery device comprises:
A voltage measuring unit for measuring a voltage between the cathode and the anode is provided.
The control device includes:
a data calculation unit that processes the voltage data received from the voltage measurement unit;
The data calculation unit calculates a first-order differential value or a second-order differential value as a feature amount based on the voltage data, and
The anode condition monitoring system is characterized in that the characteristic amount is compared with a predetermined threshold value, and when the characteristic amount is equal to or greater than the threshold value, the system diagnoses the metal recovery device as requiring maintenance. 2. The anode condition monitoring system according to claim 1, wherein the control device notifies a management terminal of the diagnosis result obtained by comparison with the threshold value via an electric communication line. 3. The anode condition monitoring system according to claim 1, wherein the object requiring maintenance is an anode coated with an electrode catalyst.

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