KR20180110833A - System for recovering metal comprising removing cyanide - Google Patents

Abstract

The present invention relates to a metal recovering system capable of removing cyanide, comprising: a metal recovering reactor; and a decomposition solution supply portion supplying a decomposition solution capable of decomposing cyanide in the metal recovering reactor, wherein the metal recovering reactor includes an electrolytic cell which is provided with a leachate including metal ions and cyanide from the outside, and reduces and precipitates metal ions of a solution on the surface of a cathode when a reacting space formed between an anode and the cathode surrounding the anode is provided with the solution.

Description

≪ Desc / Clms Page number 1 > System for recovering metal comprising removing cyanide &

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

It is common that a waste liquid, a plating waste liquid or a washing water generated in an electronic industry such as a semiconductor manufacturing process contains a useful metal. In particular, since waste water or washing water generated in an industrial process in which a precious metal is used contains a considerable amount of precious metal, it is necessary to recover and recycle the precious metal.

 In general, the method of recovering precious metals contained in waste liquid or washing water is often adopted by ion exchange resin method, activated carbon method, and electrolytic sampling method. The recovered solution may be neutralized, discarded, or semen treated and recycled.

Among them, the electrolytic collection method is a method of electrolytically reducing an aqueous solution or a leaching solution containing a noble metal as an electrolyte to deposit a desired noble metal on a cathode surface. The electrolytic harvesting method has an advantage that a high-purity metal can be obtained at a time without going through a middle step, and the solvent can be regenerated according to electrolysis and can be reused in the leaching step.

However, in the case of electrolytic harvesting, it is easy to apply when the concentration of the metal ion in the aqueous solution is high in spite of this advantage, and when the concentration is low, the rate of the metal ion moving to the surface of the negative electrode is slow, .

Further, a cyanide compound is used to dissolve a valuable metal such as waste PCB, but the efficiency of electrolytic collection is lowered by the cyanide compound.

Korea Open Patent No. 2012-0138912 (Dec. 27, 2012)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a metal recovery system including cyanide removal.

It is an object of the present invention to provide a metal recovery system including cyanide removal, comprising: a 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 is supplied with an extract solution containing metal ions and cyanide from the outside, And an electrolyzer for reducing and precipitating metal ions of the aqueous solution on the surface of the negative electrode when the aqueous solution is supplied to the reaction space formed between the surrounding negative electrode.

The decomposition solution may include secondary salts.

The cyanide may comprise KCN.

The metal ion may include gold ions.

The leach can be obtained through the leaching of 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 main negative 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 negative electrode.

The auxiliary negative electrode may be a thin plate.

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

According to the present invention there is provided a metal recovery system comprising cyanide removal.

1 is a configuration diagram of a metal recovery system according to an embodiment of the present invention,
2 is a view illustrating 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,
FIG. 5 is a schematic view showing the shape of a positive electrode of an electrolyzer according to an embodiment of the present invention,
FIG. 6 illustrates a structure of a negative electrode according to an embodiment of the present invention,
7 illustrates assembly of a negative electrode according to an embodiment of the present invention,
FIG. 8 is a perspective view of an electrolyzer according to an embodiment of the present invention,
9 is a sectional view taken along the line IX-IX 'in Fig. 8,
10 is a view showing a configuration of a chromate discharge device according to an embodiment of the present invention,
11 shows a control structure of a decalcification apparatus according to an embodiment of the present invention,
12 is a flowchart illustrating a method of operating a chromate discharge device according to an embodiment of the present invention,
FIG. 13 is a graph showing the residual gold concentration according to the addition of the secondary salt 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 operation method of performing a solid-liquid separator cleaning in a metal recovery system according to an embodiment of the present invention.

Hereinafter, 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 with reference to the accompanying drawings.

FIG. 1 is a configuration diagram of a metal recovery system according to an embodiment of the present invention, and FIG. 2 is a view illustrating a control structure of a 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 for transferring and blocking an aqueous solution (hereinafter referred to as 'aqueous solution') containing metal ions and / or metal particles to be recovered are provided. A level meter 210 for measuring the level of the auxiliary tank 200 and a timer 800 for measuring the operation time of the solid-liquid separator 300 are provided. The level meter 210 and the timer 800 And a controller 700 for controlling the operation of the pumps 501 and 502 and the valves 601, 602, 603, and 604 based on the signals. In addition, the metal recovery system 1 is provided with a decontamination supply device 900 for supplying decontamination to the electrolyzer 100.

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

The auxiliary tank 200 receives the aqueous solution electrolyzed from the electrolyzer 100. The auxiliary tank serves as a buffer between the electrolyzer 100 and the receiving tank 400 and solves the operational stability problem that may arise from the flow rate difference 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 within an appropriate range, an upper limit value, or a lower limit value. The level sensor 210 may be provided in various ways, such as by 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 the aqueous solution. The metal in the form of particles can be generated by the separation and growth of the electrolytically collected metal from the electrolyzer 100. The solid-liquid separator 300 may include, but is not limited to, a filter capable of separating particles.

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

In the receiving tank 400, an aqueous solution containing the metal to be recovered supplied from the plating process, an aqueous solution recovered from the recovered metal through the electrolyzer 100 and the solid-liquid separator 300 are combined. In another embodiment, the aqueous solution supplied through the plating process, 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- Lt; / RTI >

The metal recovery system also includes a wash section capable of washing the solid-liquid separator. The washing section includes a washing water supplying section, valves 603 and 604, a washing water discharging section, and a washing water line.

3 to 9, the electrolyzer 100 according to the first embodiment of the present invention will be described in detail.

FIG. 3 is a cross-sectional view of an electrolyzer according to a first embodiment of the present invention, FIG. 4 is a schematic exploded perspective view of an electrolyzer according to a first embodiment of the present invention, and FIG. FIG. 6 shows the structure of the negative electrode according to the first embodiment of the present invention, FIG. 7 shows assembly of the negative electrode according to the first embodiment of the present invention, FIG. FIG. 9 is a cross-sectional view taken along line IX-IX 'of FIG. 8. FIG. 9 is a perspective view of the electrolytic apparatus according to the first embodiment.

3 to 9, an electrolyzer 100 according to the present invention includes an electrolytic bath 10, negative electrodes 20 and 22, and a positive electrode 30.

The electrolytic bath 10 serves to provide a space in which an electrolytic picking process to be described later is performed. In this embodiment, the electrolytic bath 10 is formed in a cyclone shape and includes a main body portion 11 and a conical portion 15.

In the present embodiment, the main body 11 is formed in a cylindrical shape and has a constant diameter from top to bottom. An inlet 12 is formed at one side of the main body 11 so as to pass between an inner peripheral surface and an outer peripheral surface so that an aqueous solution to be described later can be introduced. And an inlet port (13) for guiding the aqueous solution to the inlet (12) is connected to the inlet (12). A connection hole 14 is formed at one side of the main body 11 so that electric wires for applying power to the negative electrodes 20 and 22 to be described later can be inserted.

In the present embodiment, the conical portion 15 extends from the lower portion of the body portion 11, and its diameter gradually decreases from the upper portion to the lower portion to form a conical shape as a whole. And an outlet 16 through which the aqueous solution flowing into the main body 11 flows out is provided below the conical portion 15. [ And an outlet port 17 for discharging the aqueous solution to the outside is connected to the outlet 16.

Further, a sealing cap 18 for opening and closing the inner space of the main body 11 is provided. The sealing cap 18 is screwed to the main body 11. The sealing cap 18 is formed on the outer circumferential surface of the sealing cap 18 by screw threads. An O-ring 18a is interposed between the sealing cap 18 and the main body 11 to ensure airtightness.

The sealing cap 18 is provided with an insertion hole 18b passing through between the upper surface and the lower surface and a rod-like positive electrode 30 to be described later is inserted into the insertion hole 18b. The O-ring 18c surrounds the insertion hole 18b to prevent the airtightness from being released between the anode 30 and the insertion hole 18b, which will be described later. The compression 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. A through hole 19c is formed at 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 and are fitted to the inside of the main body 11 and joined. In the present embodiment, the negative electrodes 20 and 22 are formed in a cylindrical shape with a constant diameter over the entire upper and lower portions as a whole.

The negative electrodes 20 and 22 include a main negative electrode 20 and an auxiliary negative electrode 22. The main negative electrode 20 is cylindrical. The auxiliary negative electrode 22 is plate-shaped, and is made to bend during assembly to be mounted inside the main negative electrode 20. Therefore, in the present embodiment, the main negative electrode 20 and the auxiliary negative electrode 22 are not physically coupled and can be attached and detached at any time, if necessary.

The inlet portion 21 formed in the main cathode electrode 20 is formed at a position corresponding to the inlet port 12 of the main body portion 11 and communicates with the inlet port 12 of the main body portion 11. [ The auxiliary negative electrode 22 also has an auxiliary inlet portion 23 corresponding to the inlet portion 21 of the main negative electrode 20. An aqueous solution containing metal ions flows into the inside of 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 inside of the cathode electrodes 20 and 22 to form a turbulent flow in the electrolytic bath 10. For this purpose, the direction in which the aqueous solution flows into the inside of the cathode electrodes 20 and 22, . That is, when a cylindrical negative electrode is assumed to be a circle, it must flow in a tangential direction from the edge of the circle. The turbulence can be formed while the aqueous solution rotates along the inner circumferential surface of the cathode electrodes 20 and 22 only when it flows in the tangential direction.

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

The main negative electrode 20 is electrically connected to a power source through a connection hole 14 formed in the main body 11. [ The main negative electrode 20 and the auxiliary negative electrode 22 are in close contact with each other and are electrically connected to each other and the auxiliary negative electrode 22 is connected to the 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 inner surface of the main negative electrode 20. Whereby the reduction and precipitation of the metal ions occur intensively on the inner surface of the auxiliary negative electrode 22. The reduction and precipitation of metal ions on the inner surface of the main negative electrode 20 may be very small or substantially not occur. Metal ion reduction and precipitation on the outer surface of the auxiliary negative electrode 22 are also very slight.

The outer surface of the main negative electrode 20, in which the reduction and precipitation of metal ions is insignificant, can be suppressed by unnecessary reduction and precipitation by Teflon coating. The inner and outer surfaces of the auxiliary negative electrode 22 smoothly deposit the noble metal and do not coat to secure electrical conductivity from the negative electrode.

When the electrolytic picking process proceeds, 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 negative electrode 20, and a post-process for separating the target metal such as gold from the auxiliary negative electrode 22 proceeds. When the metal dissolving in the acid is used as the auxiliary negative electrode 22, the noble 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 noble metal can be easily separated from the negative electrode. Nitric acid may be used for recovering the recovered metal, and the auxiliary negative electrode 22 may be cut or pulverized and treated with an acid solution for convenience of the process.

The auxiliary negative electrode 22 may be made of, for example, iron, zinc, tin, nickel or copper. It is preferable that the auxiliary negative electrode 22 has a particularly thin thickness and is in contact with the negative electrode 20 with elasticity. This is because the electric conductivity can be maintained when the auxiliary negative electrode 22 and the main negative electrode 20 are in close contact with each other. For this, the auxiliary negative electrode 22 may be made of beryllium copper and may have a thickness of 0.2 mm to 0.5 mm. Further, if the inner surface of the auxiliary negative electrode 22 to be deposited is rough, the deposited noble metal can be peeled off by the flow velocity. In order to solve this problem, the surface of the auxiliary negative electrode 22 can be mirror-finished.

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

As described above, since the auxiliary negative electrode 22 is not physically coupled to the main negative electrode 20, it is easy to insert it into the main negative electrode 20 and to separate it after the process. Thereby, only the auxiliary negative electrode 22 is separated after the process to recover the surface metal. A new process can be started when the main negative electrode 20 is maintained as it is and only the new auxiliary negative electrode 22 is inserted. In addition, since the main cathode electrode 20 has little metal precipitation, it is easy to work such as cleaning.

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

The positive electrode 30 is elongated in a rod shape and inserted into the electrolytic bath 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 the power source.

Also, the positive electrode 30 is formed in a hollow shape with its interior being hollow, and the inside of the electrolytic cell 10 communicates with the outside through the hollow portion of the positive electrode 30. The aqueous solution in the electrolytic bath 10 is lowered to the conical part 15 and then partly discharged through the outflow port 16 on the lower part of the conical part and the other part is discharged to the outside through the inside of the positive electrode 30.

On the outer surface of the positive electrode 30, a plurality of grooves 32 are formed. The grooves 32 are formed at regular intervals along the circumferential direction of the positive electrode 30 and are formed with the same width d and spacing c. The groove 32 serves to enlarge the surface area of the positive electrode 30. The formation of the grooves 32 has a lower manufacturing cost than that of forming the through holes. In addition, forming the groove 32 facilitates widening the surface area of the positive electrode 30 compared to forming the through hole. Widening the surface area of the positive electrode 30 by forming the grooves 32 affects the recovery efficiency, which will be described later.

The surface area of the positive electrode 30 can be adjusted by varying 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 another embodiment, the width d of each groove 32 may be different and may be formed at irregular intervals. The grooves 32 may be formed along the longitudinal direction of the positive electrode 30, or may be formed in a lattice shape or the like. The cross section of the groove 32 may be variously modified, such as a trapezoidal or semicircular shape other than a rectangular shape as in the embodiment.

In the present embodiment, the positive electrode 30 can be made of titanium, and the strength is increased by coating iridium oxide on titanium. The positive electrode coated with iridium oxide on titanium is not dissolved in a strongly acidic solution or a strong alkaline solution and is stably maintained. The positive electrode 30 may be coated with stainless steel or platinum.

Generally, a high decomposition voltage is required in an electrolytic sampling process. For example, when an overvoltage is applied while graphite is used as a positive electrode, the graphite anode has a weakened surface and is often worn by a fluid flowing at high speed. However, as in the present embodiment, when an electrode coated with iridium oxide or an electrode coated with platinum in stainless steel is used, the electrode is not worn and remains unchanged even at high overvoltage and high oil flow rate due to its own mechanical strength Which is advantageous in terms of stability.

The electrolyzer 100 according to the present invention is capable of effectively recovering the metal even at a low metal ion concentration, which is described in Korean Patent Publication No. 2012-0138921 of the present inventor.

The following will describe the present invention with reference to FIGS. 10 to 12. FIG.

FIG. 10 shows a configuration of a chromate discharge device according to an embodiment of the present invention. FIG. 11 shows a control structure of a chromate discharge device according to an embodiment of the present invention. FIG. 7 is a flowchart showing a method of operating a molten salt supply apparatus according to the present invention; FIG.

The supply system 900 includes a brine supply unit 910, an electrolytic module 920, a brine tank 930, connection pipes 951, 952, 953 and 954 and a decontamination control unit 940. Although not shown, pumps and / or valves are located on at least some of the connecting pipes 951, 952, 953 and 954, and include various measuring instruments. The instrument includes a timer, a pH meter, a chlorine concentration sensor, a salinity sensor, a temperature sensor, a flow meter and a level sensor.

The brine supply unit 910 supplies the brine to be electrolyzed to the electrolysis module 920. The brine supply unit 910 may supply brine with a predetermined concentration of salt water or may supply salt water using a salt tank. If salt tank is used, saturated salt water 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 the connection pipe 951 or the brine stored in the brine tank 930 through the connection pipe 954. At this time, the concentration of sodium chloride can be varied. 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 concentrations of the decontamination salt. In addition, the electrolysis target number may have various salinity. The electrolytic module 920 can use a rectifier having a constant current function to prevent the applied current from changing due to the salinity change.

The electrolytic module 920 electrolyzes the electrolytic water or the electrolytic water, and the electrolytic module 920 electrolyzes the electrolytic water. In another embodiment, there may be additional connecting piping that directly supplies the brine produced in the electrolytic module 920 to the load.

The salt water tank 930 is leveled and the level is managed. Level management can be done in several ways, and can have a lower management level and an upper management level. The lower management level is a value that does not discharge the electrolytic water of the fresh water tank 930 to the outside if it is possible to reach this value or reach this value within a certain time. The upper management level is a value that reaches this value or reaches this value within a certain time and does not supply electrolytic 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 control unit 940 controls the valve, the pump, and the like based on the measured value of the meter, for example, the concentration and level of the decontamination of the deionized water to control the sterilization of the load, the level of the deionized water tank 930, Time and / or the sodium chloride concentration of the brine.

The control method of the control unit 940 will be described in detail with reference to FIG.

First, the brine is supplied through salt water supply and electrolysis (S10).

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

The decontamination controller 940 determines whether to produce high concentration decontamination on the basis of the decontamination concentration of the decontamination water and the level measurement result of the decontamination tank 930 (S30).

The production of high concentration of brine produces the brine water of the brine tank 930 to the electrolysis module 920 to produce brine of higher concentration. This is possible because the salinity of the brine is sufficiently high. That is, since the amount of salt used in the electrolytic decomposition is small, the salinity of the primary generated brine is not much different from the salinity of the original brine. Therefore, electrolysis of the primary generated brine can produce a higher concentration of secondary brine, and electrolysis of the secondary brine can produce a higher concentration of tertiary brine.

Table 1 shows the results of the actual high concentration of deionized water produced by the above method.

Changes in salinity and chlorine concentration were tested when the salt water was produced up to 5 times. The experimental conditions are as follows.

Electrode cell structure; 240 mm ㅧ 220 ㎜ size, composed of 3 electrodes of IrO coated on Ti

Initial conditions; 1,100 ml of saline having a salinity of about 3%, a current of 130 A, a voltage of 11 to 12 V

Circulation condition; Sterilized water containing hypochlorous acid produced separately without supplying brine was used, and the flow rate was about 1,000 ml, a current of 130 A, a voltage of 11.5 to 12.5 V

The results are shown in Table 1 below.

Number of times Salinity (%) Chlorine concentration (ppm) 1 time 2.8 1,600 Episode 2 2.6 3,400 3rd time 2.6 4,200 4 times 2.5 5,200 5 times 2.5 5,400

As shown in Table 1, it can be seen that the concentration of sodium chloride in the salt water is steadily increasing without decreasing the salt concentration by the number of electrolysis.

If it is determined that the drainage control unit 930 is in conformity with the high concentration brine production condition, the brine of the brine tank 930 is supplied to the electrolysis module 920 through the connection pipe 954 (S40).

Criteria for determining the production of high-concentration brine can vary widely. For example, it may be a standard that the level of the brine tank 30 is higher than a certain level and the concentration of the brine salt of the brine is lower than a certain level. Also, the operating condition of the electrolyzer 100, for example, whether or not the operation is stopped can be a standard.

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

The liquid (the liquid to be recovered) of the receiving tank 400 is supplied to the electrolyzer 100 by the first pump 501. Specifically, the water is supplied into the electrolyzer 100 through the inlet 12 of the electrolyzer 100. Power is connected to the negative electrodes (20, 22) and the positive electrode (30) of the electrolyzer (100).

The inflow rate when the leach solution is introduced into the electrolyzer 100 is in the range of 2 to 10 m / sec. If the flow rate is less than 2 m / sec, the desired result can not be obtained because the turbulence is not generated in the negative electrode. If the flow rate is more than 10 m / sec, it is not economical.

The leachate flows in the tangential direction of the negative electrodes 20 and 22 and descends while rotating along the inner circumferential surface of the negative electrodes 20 and 22 so that part of the leachate is discharged through the outflow port 16, And is discharged. In this way, the leaching solution flowing in the tangential direction in the cyclone type electrolytic cell is discharged through the inside of the positive electrode while forming a rising current in the lower part of the electrolytic cell.

The positive electrode 30 and the negative electrodes 20 and 22 are energized through the leaching solution in the electrolytic cell and metal ions such as gold, silver and platinum are reduced by receiving electrons emitted from the negative electrode, .

In the conventional electrolytic harvesting, metal recovery through electrolytic harvesting can be effectively performed when metal ions in the leaching solution are present in an amount of 3 g / L or more. However, in the present invention, This is because a cyclone-type electrolytic cell is used and the migration speed of metal ions is fast.

The leachate forms a turbulent flow in the electrolytic cell. The formation of this turbulence is also confirmed by the relationship between the non-dimensional constant Reynolds number (Reynolds number, Re) representing the flow rate and the dimensionless constant Sherwood number (Sherwood number, Sh) .

Turbulent formation is due to the inherent geometry of the cyclone. In this turbulent flow, the mass transfer of the metal ions is rapidly accelerated. That is, since the diffusion layer, the diffusion distance of the metal ions, becomes thinner, the diffusion distance of the metal ions to the surface of the cathode is relatively shortened and the reaction rate is increased. In particular, metal ions, which are inherent characteristics of turbulence, randomly fluctuate, which moves the metal ions instantaneously to the surface of the negative electrode, thereby rapidly increasing the mass transfer.

After the electrolysis 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 receiving tank 400. This is because the flow rate of the pump 501 for supplying the liquid to the electrolyzer 100 and the flow rate of the liquid between the electrolyzer 100 and the pump 502 for supplying the liquid to the receiving tank 400 do not coincide with each other Thereby eliminating the process instability.

The leachate of the auxiliary tank 200 is supplied to the solid-liquid separator 300 by the second pump 502. In the solid-liquid separator (300), the metal particles in the leach solution are separated and only the liquid phase is supplied to the receiving tank (400).

After the operation is stopped for a predetermined time, the metal recovered from the metal electrodeposited on the auxiliary negative electrode 22 and the metal separated from the solid-liquid separator 300 in the electrolyzer 100 is operated again.

In the above-described metal recovery step, continuous operation is stably performed by the auxiliary tank 200, and the economical efficiency is very high. In addition, by using the solid-liquid separator 300, metals which are liable to be separated from the cathode electrodes 20 and 22 are effectively recovered, and the continuous operation is stably performed. Also, the electrolytic cell 100 and the solid-liquid separator 300 can be used at the same time to effectively treat the leaching solution having two or more components having different recovery characteristics.

On the other hand, the leaching solution may contain a cyanide compound. Cyanide compounds are used to leach metals contained in waste PCBs, especially precious metals such as gold. However, when the leaching solution contains a cyanide compound, the noble metal electrolytically deposited on the cathode 20 of the electrolyzer 100 is redissolved by the cyanide compound, making it difficult to recover the noble metal.

Therefore, the cyanide compound should be removed. In the present invention, a decomposition solution capable of decomposing the cyanide compound is used. Specifically, the cyanide compound is decomposed by supplying decahydrate in the decahydrate supply device 900. The cyanide compound is oxidized by cyanide to cyanogen and then to carbon dioxide and nitrogen.

The noble metal recovery behavior according to the supply of the decahydrate is as shown in Fig.

In the experiment, KCN was used as a cyanide and the residual gold concentration (ppm) of the leachate was observed at 0, 10, 30, 60, 120, 240 and 480 min. The amount of the leach solution was 7.4 liters, the flow rate was 10 liters / min, the flow rate was 5.03 meters / sec, and the applied current was 3.5A. The sodium salt concentration in the leach solution was 5000 to 5100 ppm.

The most effective recovery behavior was shown when 1.0 to 2.0 kg of secondary salt per kg of KCN was added. That is, the efficiency of recovery of noble metal is excellent when the titration salt is put in one to two times the weight of the cyanide compound.

Hereinafter, the operation in the case where there is a problem in the level of the auxiliary tank 200 different from the process in the steady state described above, and the operation in the case where the solid-liquid separator 300 is cleaned will be described.

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

In the normal operation (S100), the flow rate of the auxiliary tank 200 changes due to the difference in the flow rate of the fluid passing between the pumps 501 and 502. The level of the auxiliary tank 200 is continuously decelerated when the flow rate supplied to the solid-liquid separator 300 is higher than the flow rate supplied to the electrolyzer 100, and conversely, the level of the auxiliary tank 200 continuously increases. When the reduced level and the increased level are above a certain level, the auxiliary tank 200 can not function as a proper buffer.

The controller 700 receives the level value from the level sensor 210 of the auxiliary tank 200 and determines whether the level is between a high level and a low level at which the level is set (S110)

If the level value is very low, which is below the low level, the controller 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 predetermined time has elapsed, the controller 700 determines the level again and operates the second pump 502 to operate normally (S140) if the level is between the high level and the low level.

The controller 700 may stop the operation of the second pump 502 so that the level of the auxiliary tank 200 is maintained at a certain level (e.g., 50%, 60%, 70%, etc.) ), The pump 502 can be reactivated. It is also possible to reduce the operation flow rate without stopping the operation of the pump 502.

If the level value is extremely high or higher, the controller 700 stops the operation of the first pump 501 that supplies the aqueous solution of the electrolyzer 100 (S130). Whereby the level of the auxiliary tank 200 is reduced. After a predetermined time has elapsed, the controller 700 determines the level again and operates the first pump 501 to perform normal operation (S140) if the level is between the high level and the low level.

The controller 700 stops the operation of the first pump 501 so that the level of the auxiliary tank 200 is maintained at a certain level (e.g., 30%, 40%, 50%, etc.) ), The first pump 501 can be restarted. Further, it is also possible to reduce the operation flow rate without stopping the operation of the first pump 501.

The control unit 600 may increase the flow rate of the first pump 501 and reduce the flow rate of the second pump 502 when the level of the auxiliary tank 200 is low, When the level is high, the flow rate of the pump 501 can be decreased and the flow rate of the pump 502 can be increased. This adjustment may also be performed at any time so that the level of the auxiliary tank 200 becomes a certain level (for example, 40%, 50%, 60%, etc.).

By the level control of the auxiliary tank 200 as described above, the buffering function of the auxiliary tank 200 can be stably maintained, 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.

During the normal operation, the cleaning operation is started by the determination of the start of cleaning of the control unit 600 (S200). The control unit 600 can determine the start of the cleaning operation every predetermined operation time based on the time information received from the timer 800.

In another embodiment, the control unit 600 can determine the start of cleaning based on the pressure of the solid-liquid separator 300 (when the pressure exceeds a predetermined level), the control unit 600 determines whether the metal concentration of the aqueous solution The higher the concentration, the faster the cleaning is started).

When it is determined that the start of cleaning is started, 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). Thereby, in the electrolyzer 100 and the solid-liquid separator 300, the aqueous solution flow disappears.

Next, the cleaning unit is operated. 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, washed with the solid-liquid separator 300, and discharged to the washing water discharging unit (S240).

When the cleaning 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 turned off (S250). Thereby, the washing water supply part and the washing water discharge part are separated from the solid-liquid separator 300, and the operation of the washing part is stopped.

After completing the cleaning process as described above, the normal operation (S260) is performed.

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

When the electrolyzer 100 is provided in parallel, when a metal electrodeposited from one electrolyzer 100 is recovered, the continuous process can be maintained using another electrolyzer 100.

When the solid-liquid separator 300 is provided in parallel, it is possible to maintain the continuous process by using another solid-liquid separator 300 even in the case of cleaning one solid-liquid separator 300 or recovering metal from the filter.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. There will be. Accordingly, the true scope of protection of the present invention should be determined only by the appended claims.

Claims (9)

A metal recovery system comprising cyanide removal,
Metal recovery reactor;
And a decomposition solution supply unit for supplying a decomposition solution capable of decomposing cyanide to the metal recovery reactor,
The metal recovery reactor includes:
And an electrolyzer for reducing and precipitating the metal ion of the aqueous solution on the surface of the negative electrode when the aqueous solution is supplied to the reaction space formed between the positive electrode and the negative electrode surrounding the positive electrode and supplied with the leaching solution containing the metal ion and the cyanide from the outside, Metal recovery system. The method according to claim 1,
Characterized in that the decomposition solution comprises a secondary salt. 3. The method of claim 2,
RTI ID = 0.0 > 1, < / RTI > wherein the cyanide comprises KCN. 3. The method of claim 2,
Wherein the metal ion comprises gold ions. 3. The method of claim 2,
Wherein the leach liquor is obtained through leaching of waste PCB. 3. The method of claim 2,
Wherein 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 according to claim 6,
Wherein the main negative electrode is annular,
Wherein the auxiliary negative electrode is in a plate shape and is wound and positioned in the main negative electrode. 8. The method of claim 7,
Wherein the auxiliary negative electrode is in the form of a thin plate. 9. The method of claim 8,
Wherein the auxiliary negative electrode is in close contact with the main negative electrode,
And the auxiliary negative electrode covers substantially all the inner surface of the main negative electrode.

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