Metal recovery device

Abstract

The present invention provides a technology that makes it possible to recover a target metal easily and highly efficiently. A metal recovery device (1) recovers a target metal from a waste (9E) that is an object. The metal recovery device (1) comprises an adsorption mechanism (20). The adsorption mechanism (20) brings a filter (21) into contact with an extraction solution (LQ1) in which the target metal is dissolved, thereby causing the target metal in the extraction solution LQ1 to be adsorbed onto the filter (21). A powder capable of adsorbing the target metal is attached to the filter (21) in advance.

Description

Metal Recovery Equipment

[0001] The subject matter disclosed herein relates to metal recovery devices.

[0002] Recovering rare and precious metals from waste materials such as electronic equipment (E-waste) has been attracting attention in recent years because it is far more efficient than extracting new metal resources from mines and places less of a burden on the environment.

[0003] For example, Patent Document 1 discloses a method for recovering a target metal from a noble aqueous solution containing the target metal. Specifically, the method includes a dissolution step, which includes dissolving the target metal from a solid source material with a leachate to form a noble aqueous solution containing target metal ions, a biosorption step, which includes contacting microorganisms with the noble aqueous solution so that at least a portion of the target metal is biosorbed by the microorganisms, the microorganisms containing the metal, and the noble aqueous solution becomes a barren solution, a separation step, which includes substantially separating the metal-containing microorganisms from the barren solution, and a recovery step, which includes recovering the target metal from the metal-containing microorganisms.

[0004] Special table 2019-535910 publication

[0005] However, when microorganisms are directly added to an extract as in Patent Document 1, it is necessary to separate and recover the microorganisms from the extract after adsorption. Methods for separating microorganisms from an extract include centrifugation and filtration, but each method has its own problems.

[0006] For example, with the centrifugation method, the processing time is long, making it difficult to efficiently recover the target metal. Furthermore, the introduction and operation of centrifuge equipment is costly, making it difficult to process large amounts of extract. With the filtration method, processing time is long and maintenance work, such as replacing the filter paper, increases. Furthermore, clogging of the filter paper reduces the recovery rate of microorganisms. Therefore, there is a demand for technology that allows for easy and efficient recovery of target metals.

[0007] An object of the present invention is to provide a technique that allows for easy and highly efficient recovery of target metals.

[0008] In order to solve the above problem, the first aspect is a metal recovery device that recovers a target metal from an object, and is equipped with an adsorption mechanism that brings a filter, to which a powder capable of adsorbing the target metal has been previously attached, into contact with a metal solution in which the target metal has been dissolved, and adsorbs the target metal in the metal solution onto the filter.

[0009] A second aspect is the metal recovery device of the first aspect, wherein the filter has a long strip shape, and the suction mechanism has an unwinding roller that unwinds the filter and a winding roller that winds up the filter.

[0010] A third aspect is a metal recovery device of the first aspect, wherein the filter is sheet-shaped, and the adsorption mechanism has a moving part that moves the filter between a position where it is immersed in the metal solution and a position where it is exposed from the metal solution.

[0011] A fourth aspect is a metal recovery device of the first aspect, in which the adsorption mechanism has a housing having an inlet and outlet for the metal solution and a liquid delivery section that delivers the metal solution to the housing, and the filter is housed inside the housing.

[0012] A fifth aspect is the metal recovery device according to any one of the first to fourth aspects, wherein the powder is a microorganism.

[0013] According to the metal recovery devices of the first to fifth aspects, since the powder capable of adsorbing the target metal is attached to the filter in advance, the powder that has adsorbed the target metal can be recovered by recovering the filter, thereby enabling easy and highly efficient recovery of the target metal.

[0014] According to the metal recovery device of the second aspect, the filter that has adsorbed the target metal can be easily recovered by the mechanism for unwinding and winding the film.

[0015] According to the metal recovery device of the third aspect, the target metal can be adsorbed onto the filter by immersing the filter in the metal solution, so that the target metal can be recovered easily.

[0016] According to the metal recovery device of the fourth aspect, the target metal can be easily recovered because the target metal can be adsorbed onto the filter by passing a metal solution through the housing.

[0017] According to the fifth aspect of the metal recovery device, commercially available baker's yeast (dried cells) and torula yeast (dried cells) are inexpensive and widely available in large quantities, making it possible to keep the cost of the separation agent low. Furthermore, metal recovery after separation can be achieved relatively easily by roasting yeast containing the target metals to burn off the yeast cells. Furthermore, because metals are separated and recovered using living organisms, no petroleum-derived separation agents (e.g., ion exchange resins, solvent extractants, etc.) are used, significantly reducing the burden on the environment.

[0018] It is a figure which shows the structure of the metal recovery device based on 1st Embodiment. It is a figure which shows the structure of the metal recovery device based on 2nd Embodiment. It is a figure which shows the structure of the metal recovery device based on 3rd Embodiment.

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the components described in the embodiment are merely examples and are not intended to limit the scope of the present invention. In the drawings, the dimensions and numbers of each part may be exaggerated or simplified as necessary to facilitate understanding.

[0020] 1. First Embodiment FIG. 1 is a diagram showing the configuration of a metal recovery apparatus 1 according to a first embodiment. The metal recovery apparatus 1 is an apparatus that extracts a target metal (hereinafter referred to as the "target metal") from a processing object using an extraction solution that dissolves the metal contained in the processing object, and recovers the target metal from the extraction solution. The processing object is, for example, electronic equipment waste (hereinafter simply referred to as "waste") 9E, also known as E-waste. The target metal is, for example, a rare metal or a precious metal. Rare metals include indium, gallium, chromium, germanium, cobalt, zirconium, strontium, cesium, cerium, tungsten, tantalum, titanium, niobium, nickel, vanadium, palladium, platinum, manganese, and the like. Precious metals include gold, silver, palladium, platinum, iridium, rhodium, and the like. The following description will mainly focus on the recovery of the precious metal gold as the target metal. The materials to be treated by the metal recovery device 1 are not limited to waste electrical and electronic equipment. For example, hydrogen fuel cell systems and their constituent electrodes (such as hydrogen generation electrodes or fuel ionization electrodes), as well as electrode materials (catalytic materials) used in the electrodes, can also be treated. Furthermore, electrode ink waste, precious metal functional materials, and semiconductor wastewater can also be treated.

[0021] The metal recovery device 1 includes an extraction tank 11, an adsorption tank 13, an adsorption mechanism 20, and a control unit 30. The extraction tank 11 is a container for extracting the target metal with the extraction liquid LQ1. The extraction tank 11 is capable of storing the extraction liquid. The extraction liquid LQ1 is a chemical solution capable of dissolving the target metal. When the target metal is gold, the extraction liquid may be, for example, 50% to 100% aqua regia, an ammonium thiosulfate aqueous solution (pH 9 to 11), or an iodine aqueous solution. Furthermore, prior to extraction with the extraction liquid LQ1, a primary extraction liquid may be supplied to the extraction tank 11 for the purpose of extracting unwanted metals (e.g., base metals). The primary extraction liquid may be, for example, dilute nitric acid or a ferric chloride aqueous solution. Treating the waste 9E with the primary extraction liquid prior to the extraction liquid LQ1 allows the unwanted metals to be removed, thereby increasing the recovery efficiency of the target metal. The extraction liquid LQ1 with the dissolved target metal is an example of a "metal solution."

[0022] A nozzle 110 is disposed within the extraction tank 11. The nozzle 110 sprays the extraction liquid LQ1, for example, in a spray form. This allows the extraction liquid LQ1 to be supplied to all of the waste 9E within the extraction tank 11, thereby increasing the extraction efficiency. It is not essential that the nozzle 110 sprays the extraction liquid LQ1. For example, the extraction liquid LQ1 may be ejected from the nozzle in a shower-like manner, or may be ejected at high pressure.

[0023] The waste 9E introduced into the extraction tank 11 is preferably crushed to a predetermined size (e.g., a diameter of approximately 5 mm) in advance. This increases the extraction efficiency. To accelerate the extraction process, the extraction tank 11 may further be equipped with a heater for heating the extract liquid LQ1.

[0024] The adsorption tank 13 is a container for recovering the target metal. The adsorption tank 13 is connected to the extraction tank 11 via a pipe 15. A valve 17 and a pump 19 are disposed in the pipe 15. The valve 17 opens and closes the pipe 15. The pump 19 pressure-feeds the extraction liquid LQ1 in the pipe 15 from the extraction tank 11 to the adsorption tank 13. The valve 17 and the pump 19 are controlled by a control unit 30. By driving the pump 19 with the valve 17 open, the extraction liquid LQ1 in the extraction tank 11 is sent to the adsorption tank 13 via the pipe 15. As a result, the extraction liquid LQ1 in which the target metal has been dissolved is stored in the adsorption tank 13.

[0025] Although not shown, in order to supply the extract liquid LQ1 to the extraction tank 11, a storage tank for storing the extract liquid LQ1 and a pump and piping for sending the extract liquid LQ1 from the storage tank to the extraction tank 11 are appropriately provided. In addition, in order to discharge the extract liquid LQ1 from the adsorption tank 13, a waste liquid tank for storing the discharged extract liquid LQ1 and a pump and piping for sending the extract liquid LQ1 from the adsorption tank 13 to the waste liquid tank are appropriately provided.

[0026] The adsorption mechanism 20 includes a filter 21, an unwinding roller 22, a winding roller 23, an intermediate roller 24, and a rotation drive unit 25. The filter 21 includes a long strip-shaped substrate. The substrate may be made of a water-permeable or water-permeable material, such as cellulose-based filter paper, a membrane, or a film. The substrate is resistant to the extraction liquid LQ1, specifically, is alkali-resistant and acid-resistant. The filter 21 also includes a powder capable of adsorbing the target metal. The powder is attached to the surface of the substrate via, for example, an adhesive. It is not essential that the powder be attached to the surface of the substrate; it may be fixed inside the substrate.

[0027] The powder may be, for example, a microorganism. When the target metal is gold, examples of the microorganism include baker's yeast, torula yeast, Cupriavidus metallidurans, Chromobacterium, and Chromobacterium violaceum. Commercially available baker's yeast (dried cells) and torula yeast (dried cells) are inexpensive and readily available in large quantities, reducing the cost of these microorganisms as separation agents. Furthermore, metal recovery after separation can be achieved relatively easily by roasting the yeast containing the target metal to burn off the yeast cells. Furthermore, because this method uses organisms for metal separation and recovery, petroleum-derived separation agents (e.g., ion exchange resins, solvent extractants, etc.) are not used, significantly reducing the environmental impact. The microorganisms may be live or dead. Alternatively, components derived from the microorganisms may be added instead of the microorganisms themselves. Specifically, powders or extracts obtained by purifying components such as polysaccharides on the surface of the microorganisms (e.g., cell walls) can be used. Although microbial components do not function as living microorganisms, they can be effective in adsorbing metals.

[0028] The powder is not limited to microorganisms, and may be an inorganic or organic material. For example, a metal-organic framework (MOF) or a noria derivative may be used as the powder.

[0029] The unwinding roller 22, the winding roller 23, and the intermediate roller 24 are cylindrical members supported to be rotatable around a horizontal rotation axis. The unwinding roller 22 is arranged with the filter 21 wound around it in a roll. The unwinding roller 22 continuously unwinds the filter 21 by rotating. The winding roller 23 is arranged at a distance from the unwinding roller 22. The winding roller 23 winds up the filter 21 unwound from the unwinding roller 22. The unwinding roller 22 and the winding roller 23 are arranged above the adsorption tank 13 or at a distance above the adsorption tank 13.

[0030] The intermediate roller 24 is a member that immerses the filter 21 in the extract liquid LQ1. The intermediate roller 24 is disposed between the unwinding roller 22 and the winding roller 23. The intermediate roller 24 is positioned lower than the unwinding roller 22 and the winding roller 23. The intermediate roller 24 is disposed inside the adsorption tank 13. The intermediate roller 24 presses downward a portion of the filter 21 that is suspended between the unwinding roller 22 and the winding roller 23, thereby immersing a portion of the filter 21 in the extract liquid LQ1 stored in the adsorption tank 13. Note that a non-rotating pressing member may be used instead of the intermediate roller 24. It is desirable that the shape of the portion of the pressing member that comes into contact with the filter 21 has a curvature such as a circle. This can reduce damage to the filter 21, such as wear, caused by pressure.

[0031] The rotation drive unit 25 is a drive source such as a motor that rotates the winding roller 23. The rotation drive unit 25 is controlled by the control unit 30. When the rotation drive unit 25 rotates the winding roller 23, the filter 21 is unwound from the unwinding roller 22, and the unwound filter 21 passes through the intermediate roller 24 and is wound onto the winding roller 23.

[0032] The control unit 30 is configured by a computer having a processor such as a CPU (Central Processing Unit) and a memory such as RAM or ROM. The memory stores programs that can be executed by the computer. When the processor executes the programs, the operation of each drive unit of the metal recovery device 1 connected to the control unit 30 is controlled, and the metal extraction process by the metal recovery device 1 is carried out in a predetermined procedure.

[0033] A stirring blade 131 is disposed at the bottom of the adsorption tank 13. The stirring blade 131 is rotated by the power of a motor (not shown), thereby stirring the extract liquid LQ1 stored in the adsorption tank 13. The rotational drive of the stirring blade 131 is controlled by the control unit 30. By stirring the extract liquid LQ1, the efficiency with which the target metals are adsorbed onto the filter 21 can be increased.

[0034] In the metal recovery device 1, when the extraction process of the target metals in the extraction tank 11 is completed, the extraction liquid LQ1 is sent to the adsorption tank 13 through the pipe 15. Then, the rotation drive unit 25 of the adsorption mechanism 20 rotates the take-up roller 23, thereby continuously transporting the filter 21 from the unwinding roller 22 to the take-up roller 23. During transport, the filter 21 is pressed downward by the intermediate roller 24, thereby immersing it in the extraction liquid LQ1. In other words, the filter 21 comes into contact with the extraction liquid. As a result, the target metals in the extraction liquid LQ1 are adsorbed onto the filter 21.

[0035] The conveying speed of the filter 21 (the rotational speed of the unwinding roller 22) is set to, for example, a speed specified by the user. Alternatively, the conveying speed of the filter 21 may be automatically set by the control unit 30 according to various conditions (such as the amount of waste 9E, the components or amount of the extract LQ1, and the temperature of the extract LQ1).

[0036] According to the metal recovery device 1, the filter 21, to which the powder has been previously attached, is brought into contact with the extraction liquid, and then the filter 21 is recovered. This allows the powder to be easily recovered while minimizing loss of the powder that has adsorbed the target metal. This allows for easy and highly efficient metal recovery.

[0037] In addition, since the filter 21 is in the form of a long strip, the adsorption process can be carried out continuously and the filter 21 can be easily recovered by using a mechanism for unwinding and winding the filter 21. Furthermore, the filter 21 can be easily replaced, which improves work efficiency.

[0038] The filter 21 recovered by the winding roller 23 is, for example, calcined. The metal recovery device 1 may include a device for calcining such a filter 21. By calcining the filter 21, the base material and powder (microorganisms) are removed, and a high-purity target metal can be obtained.

[0039] 2. Second Embodiment Next, a second embodiment will be described. In the following description, elements having the same functions as elements already described will be denoted by the same reference numerals or alphabetical characters, and detailed description thereof may be omitted.

[0040] FIG. 2 is a diagram showing the configuration of a metal recovery device 1A according to a second embodiment. The metal recovery device 1A includes an adsorption mechanism 20A. The adsorption mechanism 20A includes a plurality of filters 21A, a filter holder 26, and a moving unit 27. Like the filter 21, the filter 21A includes a substrate and powder attached to the substrate. However, unlike the filter 21, the filter 21A is not elongated, but is a sheet-like member formed into a rectangular shape or the like. The filter 21A may be a thick member, such as a sponge-like member with large pores that is more permeable than filter paper and has good drainage properties.

[0041] The filter holder 26 holds a plurality of filters 21A. In this example, the filter holder 26 holds and suspends the upper portions of the plurality of filters 21A. However, the manner in which the filters 21A are held is not limited to this and can be changed as desired. Furthermore, the filter holder 26 does not necessarily have to hold a plurality of filters 21A. The filter holder 26 may be configured to hold only one filter 21A.

[0042] The moving unit 27 is a device that moves the filter holder 26 up and down in the vertical direction. The moving unit 27 has a linear motion mechanism such as a linear guide, a ball screw, an air cylinder, or a linear motor. The moving unit 27 moves the filter holder 26 in the vertical direction, thereby moving the plurality of filters 21A between a position where they are immersed in the extract liquid LQ1 and a position away from the extract liquid LQ1.

[0043] In the metal recovery apparatus 1A, when the extraction process in the extraction tank 11 is completed, the extraction liquid LQ1 is sent to the adsorption tank 13 through the pipe 15. Then, the moving unit 27 of the adsorption mechanism 20A moves the filter holder 26 downward, thereby immersing the multiple filters 21A in the extraction liquid LQ1. As a result, the target metals in the extraction liquid LQ1 are adsorbed onto the filters 21A. After a predetermined time has elapsed, the moving unit 27 raises the filter holder 26, thereby separating the multiple filters 21A from the extraction liquid LQ1. As a result, the multiple filters 21A are exposed to the extraction liquid LQ1.

[0044] Even when the adsorption mechanism 20A is employed, the target metals can be adsorbed onto the filters 21A by contacting the extract with multiple filters 21A to which powder has already been attached. Therefore, by recovering multiple filters 21A, the target metals can be recovered while minimizing the loss of the powder that has adsorbed the target metals. Therefore, the target metals can be recovered easily and efficiently. Furthermore, by increasing the number of filters 21A held by the filter holder 26, the system can be easily scaled up.

[0045] The filter 21A can also be repeatedly inserted into and removed from the extraction liquid LQ1. By inserting and removing the filter 21A, the extraction liquid LQ1 is agitated, thereby increasing the efficiency with which the target metal is adsorbed onto the filter 21A. It is not necessary to insert and remove the entire nozzle 21. For example, while at least a portion of the filter 21A is immersed in the extraction liquid LQ1, the filter 21A1 can be swung up and down (vertically) or left and right (horizontally), or the filter 21A can be rotated.

[0046] 3. Third Embodiment Figure 3 is a diagram showing the configuration of a metal recovery device 1B according to a third embodiment. The metal recovery device 1B includes an adsorption mechanism 20B. The adsorption mechanism 20B has a hollow cylindrical housing 28. The housing 28 has an inlet and outlet for the extract liquid. The inlet of the housing 28 is connected to the extraction tank 11 via piping 15. The outlet of the housing 28 is connected to the waste liquid tank 41 via piping 40. The housing 28 is formed from a material that is resistant to the extract liquid LQ1.

[0047] The housing 28 is filled with a replaceable filter 21B. Although the shape of the filter 21B is different from that of the filters 21 and 21A, they are similar in that a powder is pre-adhered to a base material. The housing 28 has a removable cap 281 on the top. In this example, the cap 281 is provided with an inlet for the extract. By removing the cap 281, the filter 21B inside the housing 28 can be replaced.

[0048] In the metal recovery apparatus 1B, when the extraction process in the extraction tank 11 is completed, the valve 17 is opened and the pump 19 is driven. As a result, the extract liquid LQ1 is sent to the housing 28 of the adsorption mechanism 20B through the piping 15. Then, as the extract liquid LQ1 passes through the housing 28, the target metals are adsorbed onto the filter 21B. Furthermore, the extract liquid LQ1 that has passed through the housing 28 is sent to the waste liquid tank 41 through the piping 40.

[0049] According to the metal recovery device 1B, the target metal is recovered by passing the extraction liquid LQ1 through the housing 28. This allows the size of the device to be easily reduced. In addition, the filter 21B can be easily replaced, which increases work efficiency.

[0050] The metal recovery apparatus 1B may also include a circulation pipe 29 that circulates the extractant LQ1 between the extraction tank 11 and the housing 28. The circulation pipe 29 is connected, for example, to an intermediate portion of the pipe 40 and to the extraction tank 11. To return the extractant LQ1 to the extraction tank 11, a valve 291 that opens and closes the flow path and a pump 293 that pumps the extractant LQ1 are appropriately provided. The valve 291 is provided, for example, between the waste liquid tank 41 and the pipe 40 at a connection point with the circulation pipe 29. The pump 293 is provided, for example, in the circulation pipe 29. Circulating the extractant LQ1 can increase the efficiency with which the target metals are adsorbed onto the filter 21B. Furthermore, the extractant LQ1 can also be easily reused.

[0051] 4. Modifications Although the embodiments have been described above, the present invention is not limited to the above and various modifications are possible.

[0052] For example, in the metal recovery apparatuses 1 and 1A of the first and second embodiments, the extraction treatment and the adsorption treatment are carried out in different tanks by including the extraction tank 11 and the adsorption tank 13. However, the extraction treatment and the adsorption treatment may also be carried out in a single common tank.

[0053] In addition, in the above embodiment, a case was described in which target metals were extracted and recovered from waste 9E, but target metals can also be recovered from objects other than waste 9E (for example, natural objects such as ores).

[0054] The metal solution may include a mining and industrial wastewater such as plating wastewater in which a precious metal, a rare metal, or both are dissolved. When treating a mining and industrial wastewater, the mining and industrial wastewater may be directly introduced into the adsorption tank 13.

[0055] Although the present invention has been described in detail, the above description is merely illustrative in all respects and does not limit the present invention. It is understood that countless variations not illustrated can be envisioned without departing from the scope of the present invention. The configurations described in the above embodiments and variations can be combined or omitted as appropriate as long as they are not mutually inconsistent.

[0056] 1, 1A, 1B: Metal recovery device 9E: Waste (target object) 20, 20A, 20B: Adsorption mechanism 21, 21A, 21B: Filter 22: Unwinding roller 23: Winding roller 27: Moving part 28: Housing LQ1: Extraction liquid (metal solution)

Claims

1. A metal recovery device for recovering a target metal from an object, comprising: an adsorption mechanism that brings a filter, to which a powder capable of adsorbing the target metal has been previously attached, into contact with a metal solution in which the target metal has been dissolved, thereby adsorbing the target metal in the metal solution onto the filter.

2. A metal recovery device according to claim 1, wherein the filter is in the form of a long strip, and the suction mechanism comprises an unwinding roller that unwinds the filter, and a winding roller that winds up the filter.

3. A metal recovery device as described in claim 1, wherein the filter is in the form of a sheet, and the adsorption mechanism has a moving part that moves the filter between a position where it is immersed in the metal solution and a position where it is exposed from the metal solution.

4. A metal recovery device as described in claim 1, wherein the adsorption mechanism has a housing having an inlet and outlet for the metal solution, and a liquid delivery section that delivers the metal solution to the housing, and the filter is housed inside the housing.

5. A metal recovery device according to any one of claims 1 to 4, wherein the powder is a microorganism.

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