Metal recovery apparatus

Abstract

To provide a technique capable of easily and highly efficiently recovering a target metal.SOLUTION: The device 1 for recovering metals is a device for recovering target metals from a 9E of wastes as an object. The metal recovery device 1 includes an adsorption mechanism 20. The adsorption mechanism 20 brings the filter 21 into contact with the extraction liquid LQ1 in which the target metals are dissolved, and causes the target metals in the extraction liquid LQ1 to be adsorbed onto the filter 21. Powder capable of adsorbing the target metal is attached to the filter 21 in advance.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[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 and places less of a burden on the environment than extracting new metal resources from mines.

[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 the 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. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2019-535910 Summary of the Invention [Problem to be solved by the invention]

[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. [Means for solving the problem]

[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, thereby adsorbing 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 adsorption 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 immersed in the metal solution and a position exposed from the metal solution.

[0011] A fourth aspect is a metal recovery device of the first aspect, 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.

[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. [Effects of the Invention]

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

[0014] According to the metal recovery device of the second aspect, the filter that has adsorbed the target metal can be easily recovered by using a 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 embodiment of the metal recovery device, commercially available baker's yeast (dried cells) and torula yeast (dried cells) are inexpensive and widely available microorganisms, making it possible to keep the cost of the separation agent low. Furthermore, recovery of metals after separation can be achieved relatively easily, such as 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, which significantly reduces the burden on the environment. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a diagram showing the configuration of a metal recovery device according to a first embodiment. [Figure 2] FIG. 10 is a diagram showing the configuration of a metal recovery device according to a second embodiment. [Figure 3] FIG. 10 is a diagram showing the configuration of a metal recovery device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[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 extracts a target metal (hereinafter referred to as the "target metal") from an object to be treated using an extraction solution that dissolves the metal contained in the object, and recovers the target metal from the extraction solution. The object to be treated 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. Examples of rare metals include indium, gallium, chromium, germanium, cobalt, zirconium, strontium, cesium, cerium, tungsten, tantalum, titanium, niobium, nickel, vanadium, palladium, platinum, and manganese. Examples of precious metals include gold, silver, palladium, platinum, iridium, and rhodium. In the following description, the recovery of the precious metal gold will be mainly described.

[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 an 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 is, for example, 50 to 100% aqua regia, an ammonium thiosulfate aqueous solution (pH 9 to 11), or an iodine aqueous solution. Furthermore, a primary extraction liquid may be supplied into the extraction tank 11 for the purpose of extracting unnecessary metals (e.g., base metals) before extraction with the extraction liquid LQ1. The primary extraction liquid is, for example, dilute nitric acid or a ferric chloride aqueous solution. By treating the waste 9E with the primary extraction liquid before the extraction liquid LQ1, unnecessary metals can be removed, thereby increasing the recovery efficiency of the target metal. The extraction liquid LQ1 in which the target metal is dissolved 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 improving extraction efficiency. Note that 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 (for example, a diameter of about 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 that heats 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 is 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. Note that the powder does not necessarily need to 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, the microorganism may be, for example, baker's yeast, torula yeast, Cupriavidus metallidurans, Chromobacterium, or Chromobacterium violaceum. Among the microorganisms, commercially available baker's yeast (dried cells) and torula yeast (dried cells) are inexpensive and readily available in large quantities, making their cost as a separation agent low. Furthermore, metal recovery after separation can be achieved relatively easily by roasting yeast containing the target metal to burn off the yeast cells. Furthermore, because metal separation and recovery is performed using organisms, no petroleum-derived separation agents (e.g., ion exchange resins, solvent extractants, etc.) are used, significantly reducing the environmental impact.

[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 rotatably supported 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 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 LQ1 stored in the adsorption tank 13. Note that a non-rotating pressing member may be used instead of the intermediate roller 24. The shape of the portion of the pressing member that comes into contact with the filter 21 is preferably a shape with 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 apparatus 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 drives and rotates the take-up roller 23, thereby continuously transporting the filter 21 from the unwinding roller 22 to the take-up roller 23. During the transport, the filter 21 is pressed downward by the intermediate roller 24, and is thereby immersed 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 filter 21 (the rotation speed of unwinding roller 22) is set to a speed designated by the user, for example. Alternatively, the conveying speed of filter 21 may be automatically set by control unit 30 according to various conditions (such as the amount of waste 9E, the components or amount of extract liquid LQ1, and the temperature of extract liquid 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 makes it possible to recover metals easily and efficiently.

[0037] Moreover, because 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 collected 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 be equipped with a device for calcining such 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 given the same reference numerals or alphabetical letters, 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 is equipped with an adsorption mechanism 20A. The adsorption mechanism 20A has a plurality of filters 21A, a filter holder 26, and a moving unit 27. Like filter 21, filter 21A has a substrate and powder attached to the substrate. However, filter 21A is not elongated like filter 21, but is a sheet-like member formed into a rectangular shape or the like. Note that 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 multiple 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 by 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 collecting multiple filters 21A, the target metals can be collected while minimizing the loss of the powder that has adsorbed the target metals. Therefore, the target metals can be collected 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 essential 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 FIG. 3 is a diagram showing the configuration of a metal recovery apparatus 1B according to a third embodiment. The metal recovery apparatus 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 made of a material that is resistant to the extract liquid LQ1.

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

[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 metal is 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 makes it easy to reduce the size of the device. In addition, the filter 21B can be easily replaced, which improves work efficiency.

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

[0051] <4. Variations> 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 one common tank.

[0053] Furthermore, in the above embodiment, the case where the target metal is extracted and recovered from the waste 9E has been described, but the target metal can also be recovered from objects other than the waste 9E (for example, natural objects such as ores).

[0054] The metal solution may include mining and industrial wastewater, such as plating wastewater, in which precious metals, rare metals, or both are dissolved. When treating 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. [Explanation of symbols]

[0056] 1, 1A, 1B: Metal recovery equipment 9E: Waste (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 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; A metal recovery device comprising:

2. The metal recovery device according to claim 1, The filter has a long strip shape, The adsorption mechanism is an unwinding roller that unwinds the filter; a winding roller that winds up the filter; A metal recovery device comprising:

3. The metal recovery device according to claim 1, The filter has a sheet-like shape, The adsorption mechanism has a moving part that moves the filter between a position where the filter is immersed in the metal solution and a position where the filter is exposed from the metal solution.

4. The metal recovery device according to claim 1, The adsorption mechanism is a housing having an inlet and outlet for the metal solution; a liquid delivery unit that delivers the metal solution to the housing; and The metal recovery device, wherein the filter is housed inside the housing.

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

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