WO2018182083A1

WO2018182083A1 - Metal recovery method including cyanide removal and metal recovery system therefor

Info

Publication number: WO2018182083A1
Application number: PCT/KR2017/003726
Authority: WO
Inventors: 오영민; 김내형
Original assignee: (주)다남이엔이
Priority date: 2017-03-30
Filing date: 2017-04-05
Publication date: 2018-10-04

Abstract

The present invention relates to a metal recovery method including cyanide removal and a metal recovery system therefor. A metal recovery method including cyanide removal according to the present invention comprises the steps of: preparing leachate containing a metal ion and cyanide; preparing an electrolyzer which receives the leachate and reduces and precipitates the metal ion of the leachate on a surface of a negative electrode when the leachate is supplied to a reaction space formed between a positive electrode and the negative electrode surrounding the positive electrode; and supplying the leachate and a decomposition solution capable of decomposing the cyanide to the electrolyzer.

Description

Metal recovery method including cyanide removal and metal recovery system therefor

The present invention relates to a metal recovery method comprising cyanide removal and to a metal recovery system therefor.

In general, useful metals are contained in waste liquids, plating waste liquids or washing water generated in the electronic industry such as semiconductor manufacturing processes. In particular, waste liquids or washing water generated in industrial processes in which precious metals are used contain a considerable amount of precious metals, and thus, it is necessary to recover and recycle them.

In general, the recovery method of precious metals contained in waste liquid or washing water is often adopted by ion exchange resin method, activated carbon method and electrolytic extraction method, and the solution after recovery may be neutralized, discarded or semi-treated and recycled.

Among them, the electrolytic extraction method is a method of electrolytic reduction of an aqueous solution or a leachate containing a noble metal as an electrolyte solution to deposit a desired noble metal on the negative electrode surface. The electrowinning method has the advantage that a high purity metal is obtained at a time without going through an intermediate step such as crude metal, and that the solvent can be regenerated and reused in the leaching process according to the electrolysis.

However, in the case of electrowinning, in spite of these advantages, it is easy to apply when the concentration of metal ions in the aqueous solution is high, and when the concentration is low, the recovery rate of the metal is reduced due to the slow speed of metal ions moving to the negative electrode surface. .

In addition, although cyanide compounds are used to dissolve valuable metals such as waste PCBs, there is a problem in that the efficiency of electrolysis is lowered by cyanide compounds.

An object of the present invention is to provide a metal recovery method including cyanide removal and a metal recovery system for the same.

The object of the present invention is to provide a leachate comprising a metal ion and a cyanide in a metal recovery method comprising the cyanide removal; Providing an electrolyzer for receiving the leachate and reducing precipitation of metal ions of the leachate on the surface of the negative electrode when the leachate is supplied to a reaction space formed between the positive electrode and the negative electrode surrounding the positive electrode; And supplying the decomposition solution capable of decomposing the cyanide and the leaching solution to the electrolyzer.

The decomposition solution may include a tea salt.

The cyanide includes KCN, and the weight ratio of the cyanide and the tea salt may be 1: 1 to 1: 2.

The metal may comprise gold.

The leaching solution may be obtained by leaching waste PCB.

The negative electrode includes a main negative electrode and an auxiliary negative electrode disposed inside the main negative electrode and detachable from the main negative electrode, and reducing and depositing a metal on an inner surface of the auxiliary negative electrode; Removing the auxiliary negative electrode from the electrolyzer; The auxiliary negative electrode may further include melting the auxiliary negative electrode using an acid solution that melts the metal and does not dissolve the metal.

The method may further include cutting or crushing the auxiliary negative electrode, and after the cutting or crushing, the auxiliary negative electrode may be melted.

The main electrode may have a ring shape, and the auxiliary negative electrode may have a plate shape and may be wound and positioned in the main electrode.

The auxiliary negative electrode may have a thin plate shape.

The auxiliary negative electrode may be in close contact with the main negative electrode, and the auxiliary negative electrode may substantially cover an entire inner surface of the main negative electrode.

The object of the present invention is a metal recovery system comprising cyanide removal, the metal recovery reactor; And a decomposition solution supply unit for supplying a decomposition solution capable of decomposing cyanide to the metal recovery reactor, wherein the metal recovery reactor receives a leachate containing metal ions and cyanide from the outside, and provides a positive electrode and the positive electrode. When the aqueous solution is supplied to the reaction space formed between the surrounding negative electrode is achieved by including an electrolyzer to reduce and precipitate the metal ions of the aqueous solution on the surface of the negative electrode.

The decomposition solution may include a tea salt.

The cyanide may comprise KCN.

The metal ion may include a gold ion.

The leachate may be obtained through leaching of the waste PCB.

The negative electrode may include a main negative electrode and an auxiliary negative electrode disposed inside the main negative electrode and detachable from the main negative electrode.

The auxiliary negative electrode may have a thin plate shape.

According to the present invention, a metal recovery method including cyanide removal and a metal recovery system therefor are provided.

1 is a block diagram of a metal recovery system according to an embodiment of the present invention,

2 is a view showing a control structure of a metal recovery system according to an embodiment of the present invention,

3 is a cross-sectional view of an electrolyzer according to an embodiment of the present invention;

4 is a schematic exploded perspective view of an electrolyzer according to an embodiment of the present invention;

5 is a positive electrode shape of the electrolyzer according to the embodiment of the present invention,

6 shows a configuration of a negative electrode according to an embodiment of the present invention,

Figure 7 shows the assembly of the negative electrode according to an embodiment of the present invention,

8 is a perspective view of a coupled state of an electrolyzer according to an embodiment of the present invention;

9 is a cross-sectional view taken along the line IX-IX 'of FIG. 8,

10 shows the configuration of a vehicle flame supply apparatus according to an embodiment of the present invention,

Figure 11 shows the control structure of the vehicle flame supply apparatus according to an embodiment of the present invention,

12 is a flowchart showing a method of operating a vehicle flame supply apparatus according to an embodiment of the present invention,

Figure 13 shows the residual gold concentration according to the addition of the flame in the metal recovery system according to an embodiment of the present invention,

14 is a flowchart illustrating an operation method according to an auxiliary tank level in a metal recovery system according to an embodiment of the present invention.

15 is a flowchart illustrating an operating method of performing a solid-liquid separator washing in a metal recovery system according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, a metal recovery reactor and a metal recovery system used in the metal recovery method according to the present invention will be described in detail.

1 is a block diagram of a metal recovery system according to an embodiment of the present invention, Figure 2 is a view showing a control structure of the metal recovery system according to an embodiment of the present invention.

The metal recovery system 1 includes an electrolyzer 100 (metal recovery reactor), an auxiliary tank 200, a solid-liquid separator 300, and a receiving tank 400.

Pumps

501 and 502 and

valves

601, 602, 603 and 604 are provided for transporting and blocking the aqueous solution containing the metal ions and / or metal particles to be recovered (hereinafter 'aqueous solution'). In addition, there is provided a timer (800) for measuring the operation time of the level measuring unit 210 and the solid-liquid separator 300, etc. for measuring the level of the auxiliary tank 200, input from the level measuring unit 210 and the timer (800) The controller 700 controls the operation of the

pumps

501, 502 and the

valves

601, 602, 603, 604 based on the signal. In addition, the metal recovery system 1 is provided with a vehicle flame supply device 900 for supplying vehicle flame to the electrolyzer 100.

The electrolyzer 100 receives an aqueous solution from the receiving tank 400 and collects (recovers) the metal from the aqueous solution by a cyclone electrolytic extraction method. The electrolyzer 100 will be described in detail again.

The auxiliary tank 200 is supplied with an aqueous solution that is electrolytically collected from the electrolyzer 100. The auxiliary tank serves as a buffer between the electrolyzer 100 and the receiving tank 400, and solves an operation stability problem that may occur due to a difference in the flow rate between the first pump 501 and the second pump 502. The auxiliary tank 200 has a level sensor 210, the level sensor 210 senses whether the level of the auxiliary tank 200 is a proper range, more than the upper limit or less than the lower limit. The level sensor 210 may be provided in various ways, such as using the total weight or pressure of the auxiliary tank 200.

The solid-liquid separator 300 separates the metal in the form of particles from an aqueous solution. The metal in the form of particles may be generated by growing and separating the metals electrolytically collected from the electrolyzer 100. The solid-liquid separator 300 is not limited thereto, but may include a filter capable of separating particles.

The aqueous solution from which the metal particles are separated in the solid-liquid separator 300 is received back into the receiving tank 400.

The receiving tank 400 combines the aqueous solution containing the recovery target metal supplied from the plating process and the aqueous solution from which the recovery target metal passed through the electrolyzer 100 and the solid-liquid separator 300 is recovered. In another embodiment, the aqueous solution supplied from the plating process and the aqueous solution passed through the electrolyzer 100 and the solid-liquid separator 300 are not combined, and the aqueous solution passed through the electrolyzer 100 and the solid-liquid separator 300 is a separate facility / process. Can be processed through

The metal recovery system also includes a wash section for cleaning the solid-liquid separator. The washing unit includes a washing water supply unit,

valves

603 and 604, a washing water discharge unit, and a washing water line.

An electrolyzer 100 according to a first embodiment of the present invention will be described in detail with reference to FIGS. 3 to 9.

3 is a cross-sectional view of an electrolyzer according to the first embodiment of the present invention, FIG. 4 is a schematic exploded perspective view of the electrolyzer according to the first embodiment of the present invention, and FIG. 5 is a first embodiment of the present invention. The shape of the positive electrode of the electrolyzer, Figure 6 shows the configuration of the negative electrode according to the first embodiment of the present invention, Figure 7 shows the assembly of the negative electrode according to the first embodiment of the present invention, Figure 8 is the present invention 9 is a perspective view of the coupled state of the electrolyzer according to the first embodiment, and FIG. 9 is a cross-sectional view taken along the line IX-IX 'of FIG. 8.

3 to 9, the electrolyzer 100 according to the present invention includes an electrolytic cell 10,

negative electrodes

20 and 22, and a positive electrode 30.

The electrolytic cell 10 is to provide a space for the electrolytic extraction process to be described later. In the present embodiment, the electrolytic cell 10 has a cyclone shape, and includes a main body portion 11 and a cone portion 15.

In the present embodiment, the main body 11 is formed in a cylindrical shape and the diameter is constant from the top to the bottom. And one side of the main body portion 11 is formed with an inlet 12 penetrating between the inner circumferential surface and the outer circumferential surface so that the aqueous solution to be described later is introduced. And the inlet port 13 for guiding the aqueous solution to the inlet 12 is connected to the inlet (12). In addition, one side of the main body portion 11 is provided with a connection hole 14 to insert the wire for applying power to the negative electrode (20, 22) to be described later.

In this embodiment, the cone portion 15 extends from the lower portion of the main body portion 11, the diameter gradually decreases from the top to the bottom to form a conical shape as a whole. In addition, an outlet 16 through which the aqueous solution introduced into the main body 11 flows out is provided below the cone 15. And an outlet port 17 for discharging the aqueous solution to the outside is connected to the outlet port (16).

In addition, a sealing cap 18 for opening and closing the inner space of the main body portion 11 is provided. That is, a female thread is formed on the upper inner circumferential surface of the main body portion 11, and a male thread is formed on the outer circumferential surface of the sealing cap 18, so that the sealing cap 18 is screwed to the main body portion 11. Then, the O-ring 18a is interposed between the sealing cap 18 and the main body portion 11 to ensure the sealing property.

The sealing cap 18 is formed with an insertion hole 18b penetrating between the upper surface and the lower surface, and a rod-shaped positive electrode 30 to be described later is inserted into the insertion hole 18b. The O-ring 18c is interposed around the insertion hole 18b to prevent the airtight release between the positive electrode 30 and the insertion hole 18b to be described later. And the pressing cap 19 is screwed on the upper portion of the sealing cap 18 to compress the O-ring 18c to the upper surface of the sealing cap 18 to enhance the airtightness. The through hole 19c is formed in the center of the compression cap 19 so that the positive electrode 30 can be fitted.

A negative electrode structure according to an embodiment of the present invention will be described.

The

negative electrodes

20 and 22 are generally cylindrical in shape and are fitted inside the main body 11 to be coupled. In the present embodiment, the

negative electrodes

20 and 22 are formed in a cylindrical shape with a constant diameter throughout the entire upper and lower portions.

The

negative electrodes

20 and 22 include a main negative electrode 20 and an auxiliary negative electrode 22. The main electrode 20 is cylindrical. The auxiliary negative electrode 22 has a plate shape, and is bent at the time of assembly to be mounted inside the main negative electrode 20. Therefore, in this embodiment, the main electrode 20 and the auxiliary negative electrode 22 are not physically coupled, and can be detached at any time if necessary.

The inlet 21 formed in the main electrode 20 is formed at a position corresponding to the inlet 12 of the main body 11, and communicates with the inlet 12 of the main body 11. Auxiliary inlet 23 corresponding to the inlet 21 of the main electrode 20 is also formed in the auxiliary negative electrode 22. The aqueous solution including the metal ion is introduced into the

negative electrodes

20 and 22 through the inlet 12, the inlet 21, and the auxiliary inlet 23.

In the present invention, the aqueous solution should be introduced into the negative electrode (20, 22) to form a turbulent flow in the electrolytic cell 10, for this purpose, the inflow direction in which the aqueous solution is introduced into the negative electrode (20, 22) is approximately cylindrical It must be in the tangential direction of. That is, when a cylindrical negative electrode is assumed as a circle, it must flow in a tangential direction at the edge of the circle. The solution must be introduced in the tangential direction so that turbulence can be formed while the aqueous solution rotates along the inner circumferential surfaces of the

negative electrodes

20 and 22.

For example, when flowing in the radial direction toward the center of the negative electrode, turbulence is not formed in the electrolytic cell 10, so that a desired effect cannot be obtained.

The main electrode 20 is electrically connected to a power source through a connection hole 14 formed in the main body 11. The main electrode 20 and the auxiliary negative electrode 22 are in close contact with each other and electrically connected, and the auxiliary negative electrode 22 is connected to a power source through the main negative electrode 20.

The auxiliary negative electrode 22 is in close contact with the main negative electrode 20 and substantially covers the entire inner surface of the main negative electrode 20. As a result, reduction and precipitation of metal ions occur intensively on the inner surface of the auxiliary negative electrode 22. Reduction and precipitation of metal ions on the inner surface of the main electrode 20 may be very insignificant or substantially not generated. In addition, the metal ion reduction and precipitation on the outer surface of the auxiliary negative electrode 22 is also very small.

The outer surface of the main electrode 20 in which the reduction and precipitation of metal ions is insignificant can be suppressed by Teflon coating to prevent unnecessary reduction and precipitation. The inner and outer surfaces of the auxiliary negative electrode 22 facilitate the deposition of precious metals and are not coated to secure electrical conductivity from the negative electrode.

When the electrochemical extraction process is performed, the metal to be recovered is deposited on the inner surface of the auxiliary negative electrode 22. After the process, the auxiliary negative electrode 22 is easily separated from the main electrode 20, and the post-process of separating the recovery target metal such as gold from the auxiliary negative electrode 22 is performed. When the acid-soluble metal is used as the auxiliary negative electrode 22, the precious metal such as gold or platinum is not dissolved in the acid solution, and only the auxiliary negative electrode 22 is dissolved, so that the precious metal can be easily separated from the negative electrode. Nitric acid may be used to recover the metal to be recovered. For convenience of the process, the auxiliary negative electrode 22 may be cut or pulverized and treated with an acid solution.

The auxiliary negative electrode 22 may be made of, for example, iron, zinc, tin, nickel, or copper. In particular, the auxiliary negative electrode 22 preferably has a thin thickness and is elastic and closely adheres to the main negative electrode 20. This is because the electrical conductivity can be maintained only when the auxiliary negative electrode 22 and the main negative electrode 20 are in close contact with each other. To this end, the auxiliary negative electrode 22 may be made of beryllium copper, and the thickness may be 0.2 mm to 0.5 mm. In addition, when the inner surface of the auxiliary anode electrode 22 is precipitated is rough, the precipitated precious metal may be peeled off by the flow rate. In order to solve this problem, the surface of the auxiliary negative electrode 22 may be mirrored.

The main electrode 20 may be formed of a material different from that of the auxiliary negative electrode 22, and may be made of, for example, stainless steel or titanium.

As described above, the auxiliary negative electrode 22 is not physically coupled with the main negative electrode 20, so that the auxiliary negative electrode 22 is easily inserted into the main negative electrode 20 and separated after the process. As a result, only the auxiliary negative electrode 22 may be separated after the step to recover the metal on the surface. If the main electrode 20 is kept intact and only the new auxiliary electrode 22 is inserted, a new process can be started. In addition, since the metal precipitation is insignificant in the main electrode 20, operations such as cleaning are easy.

On the other hand, when the amount of precipitation of the metal to be recovered increases, the precipitated metal may be separated from the negative electrode in the form of particles, and the separated metal particles are separated from the solid-liquid separator 300. In addition, in the case of a metal having a dendritic growth property is easily separated from the negative electrode is separated from the solid-liquid separator 300.

The positive electrode 30 is formed to have a rod shape and is inserted into the electrolytic cell 10 through the through hole 19c of the compression cap 19 and the insertion hole 18b of the sealing cap 18. The upper portion of the positive electrode 30 is electrically connected to a power source.

In addition, the positive electrode 30 is formed in a hollow shape with an empty inside so that the inside of the electrolytic cell 10 communicates with the outside through the hollow portion of the positive electrode 30. After the aqueous solution in the electrolytic cell 10 is lowered to the cone 15, a part is discharged to the outside through the outlet 16 under the cone, and the other part through the inside of the positive electrode 30.

A plurality of grooves 32 are formed on the outer surface of the positive electrode 30. The grooves 32 are formed at regular intervals along the circumferential direction of the positive electrode 30 and have the same width d and the interval c. The groove 32 serves to widen the surface area of the positive electrode 30. The groove 32 has a lower manufacturing cost than forming the through hole. In addition, forming the groove 32 is easier to widen the surface area of the positive electrode 30 as compared with forming the through hole. Increasing the surface area of the positive electrode 30 by forming the groove 32 affects the recovery efficiency, which will be described later.

The surface area of the positive electrode 30 may be adjusted by changing the width d, the gap c, and the depth y of the groove 32.

The shape and arrangement of the grooves 32 can be variously modified. In other embodiments, the width d of each groove 32 may be different and may be formed at irregular intervals. In addition, the groove 32 may be formed along the longitudinal direction of the positive electrode 30 or may be formed in a lattice form or the like. The groove 32 may be variously modified, such as a trapezoid or a semicircle, which is not rectangular as in the cross-sectional embodiment.

In this embodiment, the positive electrode 30 may be made of titanium, and the iridium oxide is coated on the titanium to increase strength. The positive electrode coated with iridium oxite on titanium remains stable without melting in strong acid solution or strong alkaline solution. In addition, the positive electrode 30 may be used by coating it with stainless steel or platinum.

In the electrowinning process, high decomposition voltages are generally required. For example, when an overvoltage is applied while using graphite as a positive electrode, the graphite positive electrode is often weakened by a fluid flowing at high speed. However, when using an electrode coated with iridium oxide on titanium or an electrode coated with platinum on stainless steel, as in this embodiment, the electrode does not wear out and remain intact under high overvoltage and fast flow rates due to its mechanical strength. Therefore, there is an advantage of excellent stability.

The electrolyzer 100 according to the present invention can effectively recover metals even at low metal ion concentrations is described in detail in Korean Patent Application Publication No. 2012-0138921 of the present applicant.

Hereinafter, the flame retardant supply apparatus 900 will be described with reference to FIGS. 10 to 12.

Figure 10 shows the configuration of the flame retardant supply apparatus according to an embodiment of the present invention, Figure 11 shows a control structure of the flame retardant supply apparatus according to an embodiment of the present invention, Figure 12 is an embodiment of the present invention Is a flow chart showing the operation method of the flame retardant supply apparatus according to.

The flame retardant supply device 900 includes a saltwater supply unit 910, an electrolytic module 920, a flame retardant tank 930, a

connection pipe

951, 952, 953, 954, and a flame retardant controller 940. Although not shown, pumps and / or valves are located on at least some of the

connection pipes

951, 952, 953, and 954, and include various instruments. Meters include timers, pH meters, chlorine concentration sensors, salinity sensors, temperature sensors, flow meters and level sensors.

The brine supply unit 910 supplies the electrolytic brine to the electrolytic module 920. The brine supply unit 910 may supply brine at a constant concentration or may supply brine using a salt tank. If salt tanks are used, saturated brine can be supplied.

The electrolytic module 920 electrolyzes the supplied brine to generate brine. The electrolytic module 920 may be supplied with brine from the brine supply unit 910 through a connection pipe 951 or stored in the brine tank 930 through the connection pipe 954. At this time, the salt concentration of the brine water may vary. In another embodiment, brine and brine may be supplied simultaneously.

That is, the electrolysis target water supplied to the electrolytic module 920 may have various salt concentrations. In addition, the electrolysis target water may have various salinities. The electrolytic module 920 may use a rectifier with a constant current function to prevent the applied current from being changed by the salinity change.

The brine generated through electrolysis in the electrolytic module 920 or the brine with increased flame concentration through additional electrolysis is supplied to the brine tank 930 through the connection pipe (953). In another embodiment, there may be additional connection piping for supplying the brine generated in the electrolytic module 920 directly to the load.

The brine tank 930 is leveled and managed. Level management can be done in several ways and can have a lower management level and an upper management level. The lower management limit level is a value that does not discharge the electrolyzed water of the brine tank 930 to the outside if it is possible to reach this value or reach this value within a predetermined time. The upper limit management level is a value which may reach this value or may reach this value within a predetermined time and does not supply electrolyzed water to the brine tank 930.

The brine of the brine tank 930 is supplied to the electrolyzer 100 through the connection pipe (953).

The controller 940 controls the valve or the pump based on the measured value of the measuring instrument, for example, the flame concentration and level of the brine, sterilizes the load, the level of the brine tank 930, and the operation of the electrolytic module 920. Time and / or flame concentration of the brine is controlled.

A control method of the controller 940 will be described in detail with reference to FIG. 12.

First, the brine is produced through the brine supply and electrolysis (S10).

The generated brine is injected into the brine tank 930 and is supplied to the electrolyzer 100 when a predetermined condition (S20). Here, the predetermined condition may mean that the level of the brine tank 930 is above a certain level. However, a predetermined condition for supplying the brine water may vary depending on the operating situation of the electrolyzer 100.

The flame control unit 940 determines whether high concentration flame is produced based on the flame concentration of the salt water and the level measurement result of the salt water tank 930 (S30).

High concentration brine production is to supply the brine of the brine tank 930 to the electrolytic module 920 to produce a higher concentration of brine. This is possible because the salinity of the brine is high enough. That is, since the amount of salt used for preparing salt during electrolysis is small, the salinity of the primary brine is not significantly different from that of the initial brine. Therefore, electrolysis of the primary brine can produce higher concentrations of secondary brine, and electrolysis of the secondary brine can again produce higher concentrations of tertiary brine.

The results of the actual high concentration of brine by the above method are shown in Table 1.

When the brine was produced up to 5 times, the salinity and chlorine concentrations were tested. Experimental conditions are as follows.

Electrode cell structure; 240mm × 220mm size, two IrO coated electrodes on Ti

Initial condition; 1,100 ml of brine with a salinity of around 3%, current 130A, voltage 11-12V

Circulation condition; Sterilized water containing hypochlorous acid produced without supplying brine is used separately.The flow rate is about 1,000ml, current 130A, voltage 11.5-12.5V

The results are shown in Table 1 below.

횟수Count	염도(%)Salinity (%)	염소농도(ppm)Chlorine concentration (ppm)
1회1 time	2.82.8	1,6001,600
2회Episode 2	2.62.6	3,4003,400
3회3rd time	2.62.6	4,2004,200
4회4 times	2.52.5	5,2005,200
5회5 times	2.52.5	5,4005,400

Looking at Table 1, it can be seen that the brine concentration of the brine increases continuously without significantly decreasing the brine concentration according to the number of electrolysis.

If it is determined that the flame control unit 930 meets the high concentration of brine production conditions, the brine of the brine tank 930 is supplied to the electrolytic module 920 through the connection pipe 954 (S40).

Criteria for determining high concentrations of brine production can vary. For example, the level of the brine tank 30 may be a certain level or more, and the salt concentration of the brine water may be a reference level or less. In addition, an operating condition of the electrolyzer 100 may be used as a reference, for example, whether the operation stops.

The metal recovery method using the metal recovery system described above will be described.

The leaching solution (solution to be recovered) of the holding tank 400 is supplied to the electrolyzer 100 by the first pump 501. Specifically, it is supplied into the electrolyzer 100 through the inlet 12 of the electrolyzer 100. Power sources are connected to the

negative electrodes

20 and 22 and the positive electrode 30 of the electrolyzer 100, respectively.

When the leachate is introduced into the electrolyzer 100, the inflow rate is in the range of 2 to 10 m / sec. If the flow rate is less than 2 m / sec, turbulence may not be generated in the negative electrode, and thus the desired performance cannot be obtained.

The leachate flows in the tangential direction of the

negative electrodes

20 and 22 and descends while rotating along the inner circumferential surfaces of the

negative electrodes

20 and 22, and part of the conical portion 15 is discharged through the outlet 16 and part of the positive electrode 30. Inflow and rise inside the hollow part of The leachate introduced in the tangential direction in the cyclone-type electrolyzer is discharged through the positive electrode while forming an upward flow in the lower part of the electrolyzer.

The positive electrode 30 and the

negative electrodes

20 and 22 are energized with each other through the leachate inside the electrolytic cell, and metal ions such as gold, silver, and platinum are received and reduced by the electrons emitted from the negative electrode. Precipitates.

In the conventional electrowinning, in general, when the metal ions in the leachate is present in more than 3g / L, the recovery of the metal through the electrowinning can be carried out effectively, in the present invention, even if the metal ion concentration in the leachate is less than 0.3g / L Sampling is possible because the cyclone electrolyzer is used to move metal ions faster.

The leachate forms turbulence in the electrolyzer, which is also confirmed by the relationship between the dimensionless constant Reynolds number (Re) representing the flow rate and the dimensionless constant Sherwood number (Sh) representing the mass transfer. Can be.

Turbulence formation is due to the inherent geometric features of cyclones. In such turbulence, the mass transfer of metal ions is rapidly accelerated. That is, since the diffusion layer, which is the distance at which the metal ions diffuse, becomes thin, the distance from which the metal ions diffuse to the cathode surface becomes relatively short, thereby increasing the reaction rate. In particular, metal ions, which are inherent in turbulent flow, cause anomalous fluctuation, which causes metal ions to move to the surface of the cathode momentarily, thereby rapidly increasing material movement.

After the electrolytic process, the leachate discharged through the outlet 16 of the electrolyzer 100 and the inside of the positive electrode 30 is supplied to the auxiliary tank 200. The auxiliary tank 200 serves as a buffer between the electrolyzer 100 and the reservoir 400. That is, it may be caused by a mismatch between the flow rate of the pump 501 supplying the leach solution to the electrolyzer 100 and the flow rate between the pump 502 supplying the leach solution from the electrolyzer 100 to the receiving tank 400. It is to relieve fair instability.

Leachate of the auxiliary tank 200 is supplied to the solid-liquid separator 300 by the second pump (502). The solid-liquid separator 300 separates the metal particles in the leachate so that only the liquid phase is supplied to the accommodation tank 400.

After the operation is stopped for a predetermined time, the electrode electrode 100 recovers the metal electrodeposited to the auxiliary negative electrode 22 and the metal separated from the solid-liquid separator 300 and operates again.

In the metal recovery process described above, the continuous operation is stably performed by the auxiliary tank 200, and thus the economic efficiency is very high. In addition, by using the solid-liquid separator 300, the metals easily separated from the

negative electrodes

20 and 22 are effectively recovered, and the continuous operation is made stable. In addition, by using the electrolyzer 100 and the solid-liquid separator 300 at the same time, it is possible to effectively treat the leachate having two or more components having different recovery characteristics.

On the other hand, the leaching solution may contain a cyan compound. Cyanide compounds are used to leach metals from waste PCBs, especially precious metals such as gold. However, in the case where the leachate contains the cyan compound, the precious metal electrolytically precipitated on the negative electrode 20 of the electrolyzer 100 is redissolved by the cyan compound, making it difficult to recover the precious metal.

Therefore, the cyan compound should be removed. In the present invention, a decomposition solution capable of decomposing the cyan compound is used. Specifically, the cyan compound is decomposed by supplying the second salt from the vehicle flame supply device 900. The cyan compound is oxidized to cyanic acid and then oxidized to carbon dioxide and nitrogen.

Precious metal recovery behavior according to the flame supply is shown in FIG.

In the experiment, KCN was used as the cyan compound, and the residual gold concentration (ppm) of the leachate was observed at 0, 10, 30, 60, 120, 240 and 480 minutes. The leaching liquid amount was 7.4 liters, the flow rate was 10 liters / minute, the flow rate was 5.03 meters / second, and the applied current was 3.5A. The tea salt concentration in the leachate was 5000 to 5100 ppm.

The most effective recovery behavior was shown when 1.0-2.0 kg of tea salt was added per kg of KCN. That is, when the tea salt is put 1 to 2 times the weight of the cyan compound, the noble metal recovery efficiency is excellent.

Hereinafter, a description will be given of the operation in the case where there is a problem in the process and the level of the other auxiliary tank 200 and the solid-liquid separator 300 described above in the normal state.

First, a case in which there is a problem in the level of the auxiliary tank 200 will be described with reference to FIG. 14.

Even in the normal operation (S100), the flow rate of the auxiliary tank 200 is changed by the difference in the flow rate between the

pumps

501 and 502. When the flow rate supplied to the solid-liquid separator 300 is greater than the flow rate supplied to the electrolyzer 100, the level of the auxiliary tank 200 is continuously reduced, and in the opposite case, the level of the auxiliary tank 200 is continuously increased. When the reduced level and the increased level are above a certain level, the auxiliary tank 200 may not serve as a proper buffer.

The control unit 700 receives a level value from the level sensor 210 of the auxiliary tank 200 and determines whether the level is between the set high and low levels (S110).

When the level value is very low or lower, the control unit 700 stops the operation of the second pump 502 for supplying the aqueous solution to the solid-liquid separator 300 (S120). As a result, the level of the auxiliary tank 200 increases. After a certain time, the control unit 700 determines the level again and operates the second pump 502 if it is between the high and low levels in normal operation (S140).

In another embodiment, the control unit 700 stops the operation of the second pump 502, and then the level of the auxiliary tank 200 is at a predetermined level (eg, 50%, 60%, 70%, etc.) between low and high. ), The pump 502 can be restarted. It is also possible to reduce the operating flow rate without stopping the operation of the pump 502.

When the level value is very high or higher, the control unit 700 stops the operation of the first pump 501 for supplying the electrolyzer 100 aqueous solution (S130). As a result, the level of the auxiliary tank 200 is reduced. After a certain time, the controller 700 determines the level again and operates the first pump 501 to operate normally if it is between a high and a low level (S140).

In another embodiment, the control unit 700 stops the operation of the first pump 501, and then the level of the auxiliary tank 200 is a predetermined level (eg, 30%, 40%, 50%, etc.) between low and high. ), The first pump 501 may be restarted. In addition, the operating flow rate may be reduced without stopping the operation of the first pump 501.

In another embodiment, when the level of the auxiliary tank 200 is low, the controller 600 increases the flow rate of the first pump 501, decreases the flow rate of the second pump 502, and reduces the flow rate of the auxiliary tank 200. If the level is high, the flow rate of the pump 501 can be reduced and the flow rate of the pump 502 can be increased. In addition, such adjustment may be performed at any time such that the level of the auxiliary tank 200 is a predetermined level (for example, 40%, 50%, 60%, etc.).

By the level control of the auxiliary tank 200 as described above it is possible to stably maintain the buffer role of the auxiliary tank 200, thereby improving the reliability of the continuous process.

Next, the operation of washing the solid-liquid separator 300 will be described with reference to FIG. 15.

The washing operation is started by the determination of the washing start of the controller 600 during the normal operation (S200). The controller 600 may determine the washing start at every predetermined driving time based on the time information received from the timer 800.

In another embodiment, the control unit 600 may determine the start of washing based on the pressure of the solid-liquid separator 300, etc. Higher concentrations may lead to faster washing start).

When it is determined that the start of the washing, the first pump 501 for supplying the aqueous solution to the electrolyzer 100 and the first valve 601 provided at the outlet of the auxiliary tank 200 are turned off (S210). Subsequently, the second pump 502 for supplying the aqueous solution to the solid-liquid separator 300 and the second valve 602 provided at the outlet of the solid-liquid separator are turned off (S220). This eliminates the flow of the aqueous solution in the electrolyzer 100 and the solid-liquid separator 300.

Next, start the cleaning unit. Specifically, the third valve 603 connected to the wash water supply unit, the second pump 502 connected to the solid-liquid separator 300, and the fourth valve 604 connected to the wash water discharge unit are turned on (S230). . Thereby, the washing water is supplied from the washing water supply unit to the solid-liquid separator 300 to wash the solid-liquid separator 300 and then discharged to the washing-water discharge unit (S240).

When the washing is completed, the third valve 603 is turned off to stop the supply of the washing water, the second pump 502 is turned off, and the fourth valve 604 is also turned off (S250). As a result, the washing water supply unit and the washing water discharge unit are separated from the solid-liquid separator 300, and the operation of the washing unit is stopped.

After the above washing process is completed, the steady state operation (S260) is performed.

The metal recovery system described above can be variously modified. In particular, a plurality of electrolyzers 100 and / or solid-liquid separator 300 may be provided in parallel for operational stability and operational continuity.

When the electrolyzers 100 are provided in parallel, when the electrodeposited metal is recovered from any one of the electrolyzers 100, the continuous process may be maintained by using another electrolyzer 100.

When the solid-liquid separator 300 is provided in parallel, even when one of the solid-liquid separator 300 is washed or metal is recovered from the filter, another solid-liquid separator 300 may be used to maintain a continuous process.

Although the present invention has been described with reference to the embodiments shown in the accompanying drawings, this is merely exemplary, and those skilled in the art may understand that various modifications and equivalent other embodiments are possible. There will be. Accordingly, the true scope of protection of the invention should be defined only by the appended claims.

Claims

In a metal recovery method comprising removing cyanide,

Providing a leaching solution containing a metal ion and a cyanide;

Providing an electrolyzer for receiving the leachate and reducing precipitation of metal ions of the leachate on the surface of the negative electrode when the leachate is supplied to a reaction space formed between the positive electrode and the negative electrode surrounding the positive electrode;

Supplying a decomposition solution capable of decomposing the cyanide and the leaching solution to the electrolyzer.
The method of claim 1,

The decomposition solution is a metal recovery method characterized in that it comprises a tea salt.
The method of claim 2,

The cyanide comprises KCN,

The weight ratio of the cyanide and the tea salt is a metal recovery method, characterized in that 1: 1 to 1: 2.
The method of claim 2,

The metal recovery method characterized in that it comprises gold.
The method of claim 2,

The leaching solution is a metal recovery method, characterized in that obtained by leaching the waste PCB.
The method of claim 2,

The negative electrode includes a main negative electrode and an auxiliary negative electrode disposed inside the main negative electrode and detachable from the main negative electrode,

Reducing and depositing a metal on an inner surface of the auxiliary negative electrode;

Removing the auxiliary negative electrode from the electrolyzer;

And recovering the metal by melting the auxiliary negative electrode using an acid solution in which the auxiliary negative electrode melts and the metal does not melt.
The method of claim 6,

Cutting or crushing the auxiliary negative electrode;

And the auxiliary negative electrode is melted after the cutting or crushing.
The method of claim 6,

The main electrode is ring-shaped,

The auxiliary negative electrode has a plate shape and is wound around the metal recovery method, characterized in that located in the main electrode.
The method of claim 6,

The auxiliary negative electrode is a metal recovery method characterized in that the thin plate-like.
The method of claim 6,

The auxiliary negative electrode is in close contact with the main negative electrode,

And the auxiliary negative electrode substantially covers an entire inner surface of the main negative electrode.
In a metal recovery system comprising cyanide removal,

Metal recovery reactor;

It includes a decomposition solution supply for supplying a decomposition solution capable of decomposing cyanide to the metal recovery reactor,

The metal recovery reactor,

When the aqueous solution is supplied to the reaction space formed between the positive electrode and the negative electrode surrounding the positive electrode is supplied with a leaching solution containing a metal ion and cyanide from the outside, and includes an electrolyzer to reduce and precipitate the metal ion of the aqueous solution on the surface of the negative electrode Metal recovery system.
The method of claim 11,

The decomposition solution is a metal recovery system, characterized in that it comprises a flame.
The method of claim 12,

The cyanide metal recovery system, characterized in that it comprises KCN.
The method of claim 12,

The metal ion is a metal recovery system comprising a gold ion.
The method of claim 12,

The leaching solution is a metal recovery system, characterized in that obtained through the leaching of the waste PCB.
The method of claim 12,

And the negative electrode includes a main negative electrode and an auxiliary negative electrode disposed inside the main negative electrode and detachable from the main negative electrode.
The method of claim 16,

The main electrode is ring-shaped,

And the auxiliary negative electrode is plate-shaped and wound and positioned in the main negative electrode.
The method of claim 17,

The auxiliary negative electrode of the metal recovery system, characterized in that the thin plate-like.
The method of claim 18,

The auxiliary negative electrode is in close contact with the main negative electrode,

And the auxiliary negative electrode covers substantially all of an inner surface of the main negative electrode.