JP6573603B2 - Metal recovery method, metal recovery device, metal recovery system, and metal particle manufacturing method - Google Patents

Description

  The present invention relates to a metal recovery method, a metal recovery device, a metal recovery system, and a method of manufacturing metal particles.

  Rare metals that exhibit excellent properties in various devices and parts have low output and high value. In recent years, the use of communication devices such as smartphones and tablet terminals has progressed, and how to secure useful metals such as precious metals by increasing the production of integrated circuits and printed circuit boards used in electronic devices has been It has become an important issue. On the other hand, with the increase in production of these industrial products, their wastes are also increasing, and the importance of recycling rare metals from this waste is increasing.

  In addition, noble metals and the like are usually present in minerals in a low-grade (low purity) state. Accordingly, there is a demand in the industry to effectively concentrate noble metals from low grade minerals.

  The refining and recovery of precious metals from waste and minerals has been industrially performed for a long time. The precious metal is separated and refined to a product-level purity after a recovery process in which the precious metal is diluted and concentrated from waste and minerals containing dilute precious metal. In the precious metal recovery process, chemical reduction with a reducing agent, substitution method with a base metal such as zinc, solvent extraction method, ion exchange resin method, electrolysis method and the like are used.

  On the other hand, in a process using a solution (typically, an electrolytic solution) such as plating, etching, or electrolytic refining, an impurity metal may be dissolved and accumulated in the solution during the process. For this reason, it is necessary to remove these impurities when reusing the solution. Moreover, when discarding a solution, it is necessary to collect valuable noble metals. The amount of metal contained in the solution after the treatment is very small, and an ion exchange resin method, an electrolytic method, or the like is used for the recovery.

JP-A-6-136465 JP-A-10-219363 JP 2013-177663 A

  As an example of the method for recovering the precious metal, for example, Patent Document 1 can be cited. This document discloses a technique for dissolving and extracting a platinum group metal from a used catalyst. Specifically, first, an inorganic acid and an oxidizing agent are sealed together with a waste catalyst in a sealed container that can block outside air. Next, a method is disclosed in which a step of increasing the concentration of the inorganic acid is performed, followed by heat extraction at a temperature of 60 ° C. to 180 ° C.

  Patent Document 1 discloses a method in which a highly concentrated corrosive inorganic acid that does not normally exist (at atmospheric pressure) is present in a sealed container. For this reason, a corrosion-resistant container is required. Therefore, there is a limit to reducing the equipment cost.

  Further, in the case of the electrolytic method, the current efficiency is extremely low when the concentration of metal dissolved in the solution is low. For this reason, there exists a problem that the time which collection | recovery requires will become long. Moreover, since the collected metal adheres to the electrode, a step of collecting the metal attached from the electrode surface is required.

  Further, in the case of the ion exchange method, the amount of metal retained per unit volume of the ion exchange resin is small and is not suitable for a high concentration metal solution. There are also problems such as low processing speed and large equipment. Furthermore, when the adsorption to the ion exchange resin is saturated, it is necessary to replace and regenerate a large amount of the ion exchange resin, which causes a problem in cost.

  In the substitution method, the reaction stops when the metal to be recovered covers the surface of the base metal. For this reason, in order to improve reaction efficiency, a powdery base metal is used. However, there was a problem that the reaction became intense and it was difficult to make it into an apparatus. In order to solve this, an apparatus is provided in which base metal particles are rubbed together in a reaction tank and the metal deposited on the base metal particles is collected (see, for example, Patent Document 2).

  Further, the invention described in Patent Document 2 collects noble metal using a substitution method. For this reason, there is no idea of reusing the solution used for recovery.

  Moreover, in the conventional noble metal recovery method, the noble metal is usually recovered until the noble metal concentration reaches about 1 mg / L. However, in the case of a solution containing a wide range of concentrations of noble metal in which the concentration of the noble metal in the solution is even lower than 1 mg / L, in order to recover it, a separate step of concentrating the solution is required. .

  In addition, as a technique for recovering noble metals from a wide concentration of noble metal solutions ranging from a high concentration to a concentration lower than 1 mg / L, the present inventors have incorporated gold, silver, and silver into a solution containing fluoride ions. By mixing silicon with a metal waste containing at least one element selected from the group of copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium, and depositing a rare metal on the silicon, A technique for recovering rare metals is disclosed (Patent Document 3).

  However, in the technique of Patent Document 3 described above, fluoride ions exist in the recovery process. For this reason, when the solution after the recovery process is discarded or reused, it is necessary to remove fluoride ions remaining after the recovery process. In particular, when recovering rare metals in the electrolyte, in the method of recovering rare metals by mixing fluoride ions and silicon, fluoride ions coexist in the solution after metal recovery. The later solution cannot be reused as the electrolyte.

  By the way, even if a recovery method using a solution containing no fluoride ions or a solution containing only a very small amount of fluoride ions can be found, in order to deposit a metal using silicon, It is necessary to consider that a part or all of the oxide film (typically, it is not covered with a silicon oxide film. If there is no special contrivance in the process of recovering the metal, the silicon film Since the surface of the metal is covered with the oxide film, the further deposition of the metal is stopped, in other words, the recovery of the metal is stopped. Since this may hinder the recovery of the metal, which may cause a cost increase, the practical use of the metal recovery technique will be delayed.

  The present invention solves at least a part of the technical problems described above, and thereby various solutions in which metals dissolve (for example, metal-containing solutions derived from so-called city mines, industrial waste liquids represented by the plating industry, etc.) A metal recovery method, a metal recovery device, and a metal recovery method that recovers metal at a high efficiency and at a low cost while not only requiring fluoride ions but also being relatively safe and reducing environmental burden. This can greatly contribute to the provision of a metal recovery system and a solution recycling method.

  Usually, an insulating layer (silicon oxide film) is formed on the surface of silicon by being exposed to the outside air. Further, as described above, in the process of recovering the metal, when the silicon is used as, for example, a reducing agent, the surface of the silicon is covered with the oxide film unless special measures are taken. Therefore, the present inventor does not need a solution containing fluoride ions typified by hydrofluoric acid, and in order to recover the metal as a solid from a solution in which the metal dissolves, the surface of the silicon is Focusing on the need to properly control not only the original so-called natural oxide film but also the metal deposition process, we have intensively studied and analyzed for the appropriate control. As a result, the present inventor has changed the way of thinking so far, and by making the liquidity of the solution in which the metal dissolves basic, the recovery of the metal can be continued for a long time. It has been found that recovery can be realized. In addition, since the metal obtained as a result of the recovery has been clarified to be extremely fine particles, the present inventor has found that the above-described device can be utilized also from the viewpoint of production of metal particles. It was. The present invention has been created based on the above viewpoints.

  Note that an insulating layer is usually formed on the surface of silicon by being exposed to the outside air. However, since various solutions in which the above metal dissolves are basic, the silicon in the solution is not covered entirely or partially by the insulating layer due to the dissolution of the silicon insulating layer. The fact that the situation is easily formed is one of the excellent features of the present invention. Here, in the meaning of “a situation where the whole or part of the silicon surface is not covered by the insulating layer”, the density of the insulating layer is reduced and / or the thickness of the dense layer is reduced ( Thinning). Therefore, it is only necessary to realize a reduction in density or a reduction in thickness to the extent that a specific metal can be recovered.

  In addition, the specific metal in the present invention is deposited by a reduction reaction of the specific metal ion. In the present invention, as shown in the following formula (1), a specific metal (M) ion dissolved in a solution (for example, an aqueous solution) (for example, a metal ion, a metal complex, or a metal complex ion) (Hereinafter also referred to as “metal ions”).

In addition, in the present invention, the aforementioned metal ions are present in a basic solution. Therefore, holes (h ⁺ ) generated in silicon by this reduction reaction, silicon, and hydroxide ions cause a reaction represented by the following formula (2) to form Si (OH) _4. Is done. Note that Si (OH) ₄ exists in an ionic state of H ₃ SiO ₄ ⁻ and H ^{+ in} the solution. As a result, it is considered that silicon oxide is hardly formed on the silicon surface. Furthermore, as shown in Formula (3), in all the reactions, (4 / n) metal atoms are involved with respect to one silicon atom. Further, the term “aqueous solution” used in this specification may include alcohol and the like. Note that this oxidation-reduction reaction proceeds even at room temperature. Therefore, since it is not necessary to perform special temperature control, it is worthy of special mention that the reaction can be realized by a very simple facility.

M ^{n +} = M + nh ⁺ (1)
Si + 4OH ⁻ + 4h ⁺ = Si (OH) ₄ (H ₃ SiO ₄ ⁻ + H ⁺ ) (2)
Si + (4 / n) M ^{n +} + 4OH ⁻ → (4 / n) M + H ₃ SiO ₄ ⁻ + H ⁺ (3)
(In the formula, n represents a valence of a metal ion to be recovered or removed, and h ⁺ represents a hole.)

  For example, in the case of recovering gold (Au), since gold is trivalent (3+), when one gold atom is reduced, three holes are generated in silicon. That is, it can be seen that 4/3 gold atoms are involved in the oxidation of one silicon atom.

  As described above, the metal recovery method of the present invention can sufficiently recover a specific metal even when a specific metal ion is contained in a trace amount in the recovery step. Further, in the process of depositing metal or recovering metal, it is possible to prevent with high probability that the silicon surface is covered with the oxide film, so that it is possible to continue metal deposition or metal recovery for a longer time. It becomes possible. In addition, when there is no fluoride ion in the recovery process, there is no need for a step of removing fluoride ions, so that the recovery process is extremely easy, especially in the industry, and an apparatus configuration for recovery is provided. It is worth noting that it can be greatly simplified.

  One method of recovering a metal of the present invention is a basic first method including ions of at least one element selected from the group consisting of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium. A deposition step of bringing the solution into contact with particulate silicon and depositing a metal composed of the aforementioned element on the silicon, and a recovery step of recovering the metal composed of the element deposited on the silicon are included.

  If the metal recovery method described above is used, the following metal recovery device and metal recovery system can be constructed.

  One metal recovery device of the present invention is a basic first containing ions of at least one element selected from the group of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium. A reaction tank for bringing the solution into contact with particulate silicon and a recovery unit for recovering the metal composed of the above-described elements deposited on the silicon are provided.

  Further, one metal recovery system of the present invention includes the above-described metal recovery device, a discharge unit that discharges the mixed solution of the above-described solution and the above-described silicon in the above-described reaction tank from the reaction tank, Solid-liquid separation means for solid-liquid separation of the discharged mixed liquid, and the recovery unit for recovering the metal composed of the aforementioned elements deposited on the separated silicon.

  As described above, with respect to each metal recovery apparatus or recovery system in the present invention, the mixed solution after contacting the silicon and the first solution does not need to contain fluoride ions. Therefore, if the mixed solution does not contain fluoride ions, the liquid portion of the mixed solution can be reused as it is. In addition, since the silicate ion derived from silicon is contained in the liquid mixture described above, it is preferable that the silicate ion does not cause any trouble in reuse. Further, according to this recovery device or recovery system, a metal waste or low-grade mineral containing at least one element selected from the group of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium It becomes possible to continue the precipitation or recovery of the metal composed of the element from the first solution in which is dissolved.

  Further, the method for producing one metal particle of the present invention is a basic method comprising ions of at least one element selected from the group consisting of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium. A deposition step of bringing the first solution and particulate silicon into contact with each other, and depositing a metal composed of the aforementioned element on the silicon; and a recovery step of collecting the metal composed of the aforementioned element deposited on the silicon. In the recovery step, a particulate metal composed of the above-mentioned element is generated by bringing the silicon into which the metal composed of the above-mentioned element is deposited into contact with a metal recovery solution that dissolves the above-described silicon.

  According to this method for producing metal particles, silicon can be lost or reduced by the above-described recovery step, so that at least one selected from the group consisting of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium. Metals derived from the ions of the seed elements can be produced as powders, granules or scales. For this reason, the manufactured metal can be easily utilized for various purposes.

  Further, the method of reusing one solution of the present invention includes the above solution containing ions of at least one element selected from the group of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium. And a deposition step for bringing the metal composed of the aforementioned element onto the silicon, and a removal step for removing the silicon deposited with the metal composed of the aforementioned element from the aforementioned solution.

  More specifically, the solution after the electrolytic treatment (typically, the electrolytic solution) is treated on the silicon using the same reaction mechanism as that of the above-described metal recovery method, so that gold, silver, copper, palladium is deposited on the silicon. Depositing at least one element selected from the group consisting of rhodium, platinum, iridium, ruthenium, and osmium. The solution from which the metal from each element is removed by passing through the step of separating the silicon from which the metal from the specific element is removed and the silicon from which the metal from the specific element is deposited (separation step) ( For convenience, a “second solution” can be obtained. Accordingly, the second solution can be used after the solution is reused as it is or after it is prepared by introducing another drug or the like as necessary. Since the above-mentioned second solution contains silicon-derived silicate ions, it is preferable that the silicate ions do not cause trouble when the second solution is reused.

  In the present invention, the metal recovery method and the solution reuse method have different purposes for executing the method, but both adopt the same reaction mechanism. When the purpose is metal recovery, the metal recovery method is used, and when the solution is regenerated, the solution reuse method is used. Therefore, there may be cases where both metal recovery and solution regeneration are aimed. In this case, both metal recovery and solution regeneration are performed.

  By utilizing the solution reuse method described above, a solution reuse system can be created. Specifically, the recycling system comprises a first solution comprising ions of at least one element selected from the group of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium; A reaction tank in contact with silicon, a discharge part for discharging the liquid mixture of the second solution in the reaction tank and the above-described silicon that has been contacted from the reaction tank, and solid-liquid separation of the discharged liquid mixture A solid-liquid separation means that collects the metal composed of the element deposited on the separated silicon, and reuses the third solution obtained by the solid-liquid separation means. .

  The solution recycling system includes a metal containing at least one element selected from the group consisting of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium from a solution (eg, waste liquid). Precipitate. Moreover, the solid solution containing the deposited metal and the solution from which the metal has been removed are separated by solid-liquid separation of the mixed solution after the silicon and the solution are brought into contact with each other. By this solution reuse system, the separated solution is reused (sometimes referred to as regeneration).

  According to one metal recovery method of the present invention, the metal recovery apparatus of the present invention, and the metal recovery system of the present invention, gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium From the first solution in which the metal waste or low-grade mineral containing at least one element selected from the group is dissolved, it is possible to continue the precipitation or recovery of the metal comprising the element for a longer time. .

  According to the method for producing one metal particle of the present invention, a metal derived from ions of at least one element selected from the group consisting of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium. It can be produced as a powdery product, a granular product, or a scale-like product.

  In addition, according to one solution recycling method of the present invention, as a solution obtained as a result of employing the above-described metal recovery method, the metal recovery device of the present invention, and the metal recovery system of the present invention, An original solution with the metal removed is obtained. Therefore, the solution can be used after being prepared by introducing a drug or the like as necessary, or the solution can be reused as it is.

It is the schematic which shows an example of a structure of the metal collection | recovery apparatus 100 in this embodiment. It is the schematic which shows another example of a structure of the metal collection | recovery apparatus 100 in this embodiment. It is the schematic which shows another example of a structure of the metal collection | recovery apparatus 100 in this embodiment. It is a conceptual diagram which shows another usage condition of the silicon | silicone accommodating part in this embodiment. It is a schematic diagram of a metal recovery system showing an example of a metal recovery system of this embodiment. It is a graph which shows collection | recovery of gold | metal | money for every processing time from the 1st solution containing a gold ion. It is a graph which shows collection | recovery of the platinum for every process time from the 1st solution containing the ion of platinum. It is a graph which shows the collection | recovery of the copper for every processing time from the 1st solution containing a copper ion. It is a graph which shows collection | recovery of the palladium for every processing time from the 1st solution containing the ion of palladium. It is a graph which shows collection | recovery of the silver for every processing time from the 1st solution containing a silver ion.

DESCRIPTION OF SYMBOLS 10 Mixing / deposition processing part 11, 11 'Supply part 12 Recovery part 13 1st solution tank 14' Silicon suspension tank 15 Stirring means 16, 18 Discharge part 17 Silicon storage part 19 Liquid recovery part 20 Distribution means 21 Reaction Tank 22 Solid-liquid separation means 23 Silicon storage tank 24 First solution generation tank 26 Electrolytic treatment apparatus 27 Other solid-liquid separation means 90 Silicon 100 Metal recovery apparatus

  Embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this description, common parts are denoted by common reference symbols throughout the drawings unless otherwise specified. In the drawings, the elements of the present embodiment are not necessarily shown to scale. Moreover, in order to make each drawing easy to see, some reference numerals may be omitted.

[Basic principles for realizing this embodiment]
In the present embodiment, a solution (typically an aqueous solution) containing ions of at least one element selected from the group of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium; Contains at least one element selected from the group consisting of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium by contacting with silicon (typically particulate silicon) Metal will be deposited on the silicon. More specifically, in the present embodiment, as described above, at least one element selected from the group of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium in the solution is used. Disclosed is a reaction mechanism in which metal ions are deposited on silicon by taking electrons from silicon and reducing them to metal. In this embodiment, since the solution is basic, even if a silicon insulating layer is temporarily formed on the silicon in the solution by the above-described oxidation-reduction reaction, the insulating layer is dissolved. Since a state where the whole or part of the surface is not covered with the insulating layer is likely to be formed, the oxidation-reduction reaction can be continued with high accuracy. In addition, the solution contains silicon-derived silicate ions. Therefore, when this silicate ion does not hinder reuse, the solution can be reused.

(Processing object)
In this embodiment, an object to be processed is an object containing gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and / or osmium. The processing object is not particularly limited as long as it contains these elements. Examples of the processing object are wastes of industrial products such as communication equipment and electronic equipment, solids such as low-grade minerals, or liquids such as solutions subjected to electrolytic treatment. The above elements may be used alone or in combination of two or more. In the present embodiment, the specific metal can be selectively recovered by distinguishing between the above-mentioned one or more specific metals and other metals (for example, base metals). Above all, it is particularly useful.

In the treatment of this embodiment, the above-described elements need to be present in water in an ionic state. This is because the above-described specific metal ion reduction reaction is used in the present embodiment. Metals contained in industrial wastes and low-grade minerals may be referred to as solutions (hereinafter referred to as “first solutions” in each embodiment) using known chemicals (for example, aqua regia etc.) The description in each claim is not limited to this definition). If necessary, the first solution may be diluted with water or the like. In the case of a solution after electrolytic treatment or the like, the first solution can be used as it is. The concentration of metal ions in the first solution may vary depending on the type of metal and the amount of silicon used, but is, for example, 1 × 10 ⁻² mg / L or more, preferably 1 × 10 ⁻¹ mg. / L or more is sufficient. The upper limit of the metal ion concentration in the first solution is not particularly limited. However, in terms of the technical significance that plays the role of “recovering” the metal in the actual usage situation, it is a preferred embodiment to adopt 2000 mg / L or less (preferably 200 mg / L or less).

  Moreover, in this embodiment, that the above-mentioned specific metal element exists in the state of an ion means that it exists in states, such as a metal ion, a metal complex, or a metal complex ion, for example. Further, the first solution is basic. According to the knowledge of the present inventor, it is very preferable to adopt the first solution having a pH value of 11 or more from the viewpoint of recovering a large amount of metal with higher accuracy and speed. In addition, the upper limit of pH value is not specifically limited. However, from the viewpoint of ease of industrial handling, the pH value is preferably 14.5 or less.

(silicon)
Silicon used in this embodiment is typically a shared crystal having a diamond structure. Usually, the surface of silicon is oxidized by oxygen in the atmosphere to form a silicon oxide layer (insulating layer). However, as described above, since the first solution is basic, the silicon in the first solution is easily dissolved in the insulating layer, in other words, it is difficult to maintain the insulating layer on the silicon surface. Is easily formed.

  Note that it is preferable to use high-purity silicon from the viewpoint of easy progress of metal deposition reaction on silicon or selectivity of deposited metal. However, although the amount of silicon used may increase, silicon with low silicon purity may be used. Therefore, from the viewpoint described above, for example, it is very preferable to use silicon having a silicon purity of 99.99% or more.

  Examples of the first solution (basic solution) of the present embodiment include an alkali metal hydroxide aqueous solution (eg, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, etc.), alkaline earth metal hydroxide. Organic alkali salts such as aqueous solutions of inorganic alkali salts such as aqueous solutions of products (for example, calcium hydroxide aqueous solutions), aqueous solutions of tetraalkylamines (such as aqueous solutions of tetramethylammonium hydroxide and tetraethylammonium hydroxide), and aqueous guanidine solutions. Such as an aqueous salt solution.

  Further, the shape of silicon employed in the present embodiment is not particularly limited. However, for example, powdered or granular silicon (hereinafter collectively referred to as “granular”) silicon can have a larger surface area than other modes (for example, plate-like), and thus is suitable. It is an aspect. That is, granular silicon has more opportunities for contact with gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium and / or osmium.

  In addition, regarding the particle size of silicon, a suitable particle size can be calculated from the value of the surface area of silicon described above. For example, when granular silicon is used, the reaction efficiency increases as the particle size of silicon decreases, but handling becomes difficult. In particular, when a flow method in which the first solution is circulated in a tank filled with silicon or the like or when a filter is used for solid-liquid separation, clogging may occur. On the other hand, even if the particle size is about 1 mm, the reaction efficiency is lowered, but it can be used. Accordingly, the particle size of the granular silicon is not particularly limited, but usually, it is equal to or larger than the particle size that can be most finely divided using the technique at the time of filing the application, and is several mm ( The typical numerical value is 5 mm) or less, preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less. The lower limit of the particle size is not particularly limited, but as described above, it is preferable to employ a particle size larger than the particle size (for example, 0.5 μm or more, more preferably 5 μm or more) that can avoid clogging of the filter. This is one aspect.

  Moreover, you may employ | adopt what attached other metals etc. to the surface of the silicon | silicone of this embodiment. For example, it is relatively difficult to recover iridium using only silicon, but the recovery rate can be improved by using silver particles or gold particles previously attached to the silicon surface.

  Here, in order to efficiently recover metal ions in the first solution with as little silicon as possible, silicon corresponding to each metal ion concentration and ion valence in the solution targeted for the supply amount of silicon is used. It is desirable to supply silicon after taking into account the processing capacity per surface area.

  As a specific example showing the throughput of silicon, the present inventors consider the geometric surface area calculated from the valence and concentration of each metal in the solution and the average particle diameter of the supplied silicon particles. The value calculated in this way is one index that can be adopted.

(Metal recovery / removal)
Regarding the silicon on which the metal is deposited, the deposited metal particles can be collected after the silicon is dissolved by contacting with a metal recovery solution (for example, a basic aqueous solution). In addition, the example of the above-mentioned basic aqueous solution is the solution illustrated as the above-mentioned 1st solution (basic solution). When recovering the metal particles, a mixed solution of hydrofluoric acid and nitric acid can be employed as the metal recovery solution instead of the above basic solution. Accordingly, any metal recovery solution containing fluoride ions and containing an oxidizing agent typified by nitric acid (not limited to nitric acid) can be used as an alternative solution for the basic aqueous solution. However, from the viewpoint of combining with the above-described precipitation process (precipitation step) or liquidity in the precipitation reaction, it is preferable to employ a basic solution for the recovery of the metal.

  One type or two or more types of the above-described metals can be recovered in one step. Further, when two or more kinds of metals are simultaneously deposited, the metal containing at least two kinds of elements selected from the group consisting of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium is silicon. A composite material that adheres to the substrate is obtained. Furthermore, when two or more kinds are recovered, a plurality of kinds of metals can be separated and recovered in one step by utilizing the difference in the deposition rate of the metal.

  In this embodiment, the reaction proceeds at room temperature and normal pressure. Therefore, it is one of the advantageous features to be noted that special temperature control and pressure control are not required. However, temperature control and pressure control in this embodiment is another aspect that can be adopted.

(Metal recovery method)
<First Embodiment>
This embodiment includes at least one element selected from the group of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium (hereinafter also referred to as “specific metal”). This is an embodiment suitable when mixing the solution of No. 1 and silicon.

  FIG. 1 is a schematic diagram illustrating an example of a configuration of a metal recovery apparatus 100 according to the present embodiment. In the example of FIG. 1, the metal recovery apparatus 100 includes a first solution tank 13 and a silicon 90 containing a first solution in which a specific metal is dissolved, in addition to the mixing / deposition processing unit 10 having a reaction tank 21. Supply unit 11, discharge unit 16 that discharges silicon on which the specific metal that has undergone the mixing / deposition process has been discharged, and recovery unit 12 that recovers the specific metal from the silicon on which the specific metal has been deposited. .

  In this embodiment, the specific metal is dissolved in the first solution. That is, an example of the first solution is an aqueous solution in which a metal containing at least one element selected from the group of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium exists in an ionic state. It is. The metal recovery apparatus 100 supplies the first solution to the mixing / precipitation processing unit 10 using a normal supply unit that supplies the liquid, such as a pump.

  On the other hand, the metal recovery apparatus 100 supplies the silicon 90 to the mixing / deposition processing unit 10 by, for example, charging through the supply unit 11.

  This embodiment is performed at normal temperature and normal pressure. Therefore, the mixing / deposition treatment unit 10 may be an open system such as a water tank or a closed system.

  In order for the specific metal to be efficiently deposited on the surface of the silicon 90, it is necessary that the specific metal ions and the silicon 90 are in sufficient contact within the mixing / deposition treatment unit 10. For this reason, it is preferable that the mixing / precipitation processing unit 10 is provided with a stirring means 15. In the example of FIG. 1, a stirring blade is provided as the stirring means 15. The stirring means 15 is not limited to a stirring blade, and known stirring means such as aeration can be used.

  The solution having been subjected to the mixing / deposition treatment is recovered from a metal composed of a specific element that is discharged from the discharge unit 16 and deposited on the silicon 90 by the recovery unit 12. In this case, it is a preferred embodiment that a solid-liquid separation means is provided between the mixing / precipitation processing unit 10 and the recovery unit 12 (not shown). Examples of the solid-liquid separation means are known solid-liquid separation means such as filtration and dehydration.

  In the recovery unit 12, silicon deposited with a metal composed of a specific element is brought into contact with the above-described metal recovery solution (for example, a basic aqueous solution or a mixed solution of hydrofluoric acid and nitric acid). Dissolve and collect metal particles.

  The liquid separated by the solid-liquid separation means can be used as the liquid component of the first solution or suspension.

<Second Embodiment>
This embodiment is suitable for the case where the first solution containing a specific metal is mixed with the slurry of silicon. Further, this embodiment has a configuration that enables continuous processing.

  FIG. 2 is a schematic diagram illustrating another example of the configuration of the metal recovery apparatus 100 according to the present embodiment. In the example of FIG. 2, the metal recovery apparatus 100 includes a mixing / deposition processing unit 10 having a reaction tank 21, a first solution tank 13 containing a first solution in which at least a specific metal is dissolved, and a first A supply unit 11 for supplying the solution, a suspension tank 14 ′ containing a suspension in which silicon is suspended (silicon slurry), and the suspension is supplied from the suspension tank 14 ′. A supply unit 11 ′, a discharge unit 16 that discharges a liquid containing silicon on which a specific metal that has been mixed and deposited is deposited, and a recovery unit 12 that recovers the specific metal from the silicon on which the specific metal has been deposited. Prepare.

  In the example of FIG. 2, since the first solution and the suspension are mixed, ions of a specific metal and silicon can be efficiently contacted. The first solution and the suspension can be supplied using known supply means such as a pump. From the viewpoint of recycling, it is possible to use a suspension containing the same components as the first solution after removing a specific metal. In the example of FIG. 2, the supply unit 11 and the supply unit 11 ′ are provided separately. However, supplying the mixed solution of the first solution and the suspension to the same supply unit 11 and then supplying the mixed solution to the mixing / deposition processing unit 10 is another aspect that can be adopted. In this case, the first solution and the suspension may be separately introduced into the supply unit 11, and a mixing unit (not shown) is provided, and a premixed mixture is introduced into the supply unit 11. Also good.

  Also in the example of FIG. 2, as in the example of FIG. 1, the mixing / precipitation processing unit 10 can be provided with a stirring means 15 in order to improve the contact efficiency between specific metal ions and silicon. However, in the example of FIG. 2, for example, by providing a forced mixing means such as a pump, the first solution and the suspension can be mixed and can be sufficiently brought into contact with each other without providing the stirring means 15. Good.

  In the example of FIG. 2, the first solution and the suspension are introduced from the lower part of the mixing / precipitation processing unit 10. The mixed liquid of both liquids moves from the lower part to the upper part of the mixing / deposition treatment unit 10 while the metal ions and silicon are in contact with each other and the metal is deposited. The mixed liquid of both liquids is discharged from a discharge unit 16 provided on the upper part of the mixing / deposition processing unit 10. As a result, continuous processing is possible in the example of FIG.

  On the other hand, a configuration in which the first solution and the suspension are introduced from the upper part of the mixing / precipitation processing unit 10 is also possible. In this case, although it is difficult to be suitable for continuous processing, it is possible to obtain the effect of mixing the first solution and the suspension.

  When the solution that has been subjected to the mixing / precipitation process is discharged from the discharge unit 16, the recovery unit 12 can recover a metal composed of a specific element deposited on the silicon. In this case, it is a preferred embodiment that a solid-liquid separation means is provided between the mixing / precipitation processing unit 10 and the recovery unit 12 (not shown). Examples of the solid-liquid separation means are known solid-liquid separation means such as filtration and dehydration.

  In the recovery part 12, silicon is dissolved by bringing silicon on which a specific metal is deposited into contact with the above-described metal recovery solution (for example, a basic aqueous solution or a mixed solution of hydrofluoric acid and nitric acid). Metal particles can be recovered.

  The liquid separated by the solid-liquid separation means can be used as the liquid component of the first solution or suspension.

<Third Embodiment>
In this embodiment, the first solution containing a specific metal is passed through a tank filled with silicon. Moreover, in this embodiment, the structure which does not require a solid-liquid separation means is employ | adopted. Furthermore, when this embodiment is used, a configuration that enables a device configuration corresponding to the amount of processing is obtained by combination.

  FIG. 3 is a schematic diagram illustrating still another example of the configuration of the metal recovery apparatus 100 according to the present embodiment. The metal recovery apparatus 100 of the present embodiment supplies a first solution from a column-shaped reaction vessel 21 containing silicon and a first solution vessel 13 containing a first solution in which a specific metal is dissolved. A supply unit 11, a discharge unit 18 that discharges the liquid that has passed through the reaction tank 21, and a liquid recovery unit 19 that recovers the liquid that has passed through the silicon storage unit 17 are provided.

  In the example of FIG. 3, the first solution is supplied from above. In this example, since the liquid flows using gravity, it is not necessary to provide a distribution means. However, it is another aspect that can be adopted to provide a circulation means such as a pump that promotes circulation by reducing the pressure inside the silicon accommodating portion 17 in the vicinity of the discharge portion 18.

  In the present embodiment, for example, as shown in FIG. 4, the supply unit 11 can be provided in the lower part of the reaction vessel 21. In the example of FIG. 4, the first solution is in the form of a column via the supply unit 11 that supplies the first solution from the first solution tank 13 that contains the first solution in which the specific metal is dissolved. From the lower part of the reaction tank 21 toward the reaction tank 21. In this case, the first solution passes through the silicon accommodating portion 17 by forcibly supplying the first solution to the reaction vessel 21 using the flow means 20 such as a pump. As a result, the first solution after the precipitation treatment can be discharged from the discharge portion provided in the upper part of the silicon accommodating portion 17 in the reaction tank 21.

  As long as the reaction vessel 21 can be filled with silicon, the reaction vessel 21 does not have to be columnar as shown in the examples of FIGS. For example, a structure (not shown) in which a cartridge is filled with silicon is another embodiment that can be adopted.

  In the case of this embodiment, the second solution from which the specific metal has been removed is discharged from the reaction tank 21 via the discharge unit 18. In the case of this embodiment, when all of the specific metal cannot be recovered by one operation, the liquid recovered by the liquid recovery unit 19 is additionally used as the first solution once or a plurality of times. Can be used. Accordingly, one or more additional uses are also a preferred aspect.

  In each of the embodiments so far, as described above, since the first solution (and the second solution) is basic, the silicon in these solutions is dissolved by the dissolution of the silicon insulating layer. The state where the whole or part of the surface is not covered with the insulating layer is likely to be formed. Therefore, it should be noted that the continuity of metal deposition can be significantly improved. Further, in each of the embodiments so far, when the amount of silicon to be brought into contact with the first solution decreases with the deposition of metal, silicon is added using a known supply mechanism (not shown). It is also possible.

  In the case of the present embodiment, a specific metal is recovered from silicon when all the processes are completed. In the case of the present embodiment, a metal recovery solution (for example, a basic aqueous solution, or a solution of hydrofluoric acid and nitric acid, which dissolves silicon after transferring silicon deposited with a specific metal to another container or the like). The metal may be recovered by adding a liquid mixture, or a metal recovery process may be performed by introducing a chemical that dissolves silicon into the reaction vessel 21.

  By the way, this embodiment has shown the example using one reaction tank 21. FIG. However, the present embodiment is not limited to such an example. For example, an embodiment in which a plurality of column-shaped or cartridge-shaped reaction vessels 21 are connected and used is another embodiment that can be adopted. By using the column-shaped or cartridge-shaped reaction tanks 21 connected in series and / or in parallel, appropriate processing can be performed according to the variation in the processing amount.

(Metal recovery system)
<Fourth Embodiment>
The metal recovery system according to the present embodiment is configured to utilize the metal recovery method or the metal recovery apparatus described above to construct a metal recovery system. In this metal recovery system, since a basic solution is employed in the metal deposition step and the recovery step, the metal can be recovered using a relatively simple device. Moreover, although the silicate ion derived from silicon is contained in the 1st solution after a process, if this silicate ion does not have trouble in recycling, the 1st solution can be reused. In the recovery of the metal, a mixed solution of hydrofluoric acid and nitric acid can be used as the metal recovery solution instead of the basic solution. Accordingly, any metal recovery solution containing fluoride ions and containing an oxidizing agent typified by nitric acid (not limited to nitric acid) can be used as an alternative solution for the basic aqueous solution. However, from the viewpoint of combining with the liquidity in the precipitation step, it is preferable to employ a basic solution for the recovery of the metal.

  This embodiment is a metal recovery system using the recovery device of each of the embodiments described above. FIG. 5 is a schematic diagram of a metal recovery system showing an example of the metal recovery system of the present embodiment. As shown in FIG. 5, the metal recovery system of the present embodiment includes a supply unit 11, a reaction vessel 21, a mixing / precipitation processing unit 10, a discharge unit 16, solid-liquid separation means 22, 27, and a recovery unit. 12, a silicon storage tank 23, and a solution generation tank 24.

  Note that the metal recovery system of the present embodiment is slightly different in processing contents depending on the configurations of the first to third embodiments described above.

  Specifically, in the case of the metal recovery system using the above-described first embodiment, it is as follows.

  First, a first solution fed from a solution generation tank 24 storing a first solution containing at least one element selected from a specific metal, and silicon fed from a silicon storage tank 23 Then, it is supplied to the reaction tank 21 through the supply unit 11.

  In 10 parts of the mixing / deposition treatment in the reaction vessel 21, the first solution and silicon are mixed to deposit a specific metal. The mixed liquid after the mixing / deposition treatment (including silicon on which a specific metal has been deposited and silicon on which a specific metal has not yet been deposited) is sent from the discharge unit 16 to the solid-liquid separation means 22.

  After the solid-liquid separation means 22 separates the silicon on which the specific metal is deposited and the filtrate, the separated filtrate is sent to the solution generation tank 24 and the silicon on which the specific metal is deposited is sent to the recovery unit 12. It is done. While being sent from the solid-liquid separation means 22 to the solution generation tank 24, for example, a part of the filtrate is treated as waste liquid and the other is returned to the solution generation tank 24. In addition, in this solution production | generation tank 24, a new chemical | medical agent may be added, for example, and the solution of the solution production | generation tank 24 can be reused as a solution for metal dissolution. In addition, when reusing as a solution for melt | dissolving a metal, it is one suitable aspect | mode which throws in this metal additionally so that the density | concentration of the ion of a specific metal in the reaction tank 21 may not fall. On the other hand, without returning the solution in the solution generation tank 24 to the reaction tank 21 in the metal recovery system shown in FIG. 5, a mode in which the solution is separately used in a similar metal recovery system (a so-called batch process) ) Is another aspect that can be employed. In addition, discarding a part of the filtrate outside the metal recovery system is another aspect that can be adopted.

  In the recovery unit 12, as in each of the above-described embodiments, at least one of silicon is brought into contact with the above-described metal recovery solution (for example, a basic aqueous solution or a mixed solution of hydrofluoric acid and nitric acid). Dissolve the parts. The respective solutions for dissolving silicon and the metal to be recovered sent from the recovery unit 12 and the recovery target metal are separated by using the solid-liquid separation means 27, whereby the recovery of specific metal particles and the like can be realized.

  In one modification of the fourth embodiment, the above-mentioned silicon sent to the solid-liquid separation means 27 can be reused for the above-mentioned metal recovery. Specifically, after the metal is recovered in the recovery unit 12, the above-described silicon sent to the solid-liquid separation means 27 is sent to the silicon storage tank 23 via the route indicated by the arrow X in FIG. It is done. As a result, the silicon can be reused for metal recovery. In the present embodiment, for example, the above-described silicon sent to the solid-liquid separation unit 27 may be directly sent to the supply unit 11 without providing the silicon storage tank 23. is there.

  When this metal recovery system is used, even if not all of the specific metal in the first solution can be recovered by a single operation, it can be recovered by a plurality of operations.

  Further, in the case of the metal recovery system using the second embodiment described above, for example, a first solution is configured using a suspension preparation tank (not shown) and using silicon in the silicon storage tank 23. Make a suspension previously suspended in the liquid. This suspension is supplied from the supply unit 11 to the reaction vessel 21.

  In addition, since the other structure of the above-mentioned 2nd Embodiment is the same as each structure of the metal collection | recovery system using the above-mentioned 1st Embodiment, description is abbreviate | omitted.

  In the case of the metal recovery system using the third embodiment described above, the reaction tank 21 is filled in advance using silicon in the silicon storage tank 23. Thereafter, the first solution is supplied from the supply unit 11 to the reaction vessel 21. In the case of this metal recovery system, what is discharged from the reaction vessel 21 is a solution from which at least a part of a specific metal has been removed. Therefore, in the case of the metal recovery system using the above-described third embodiment, the reaction tank 21 can also function as the solid-liquid separation means 22.

  In the case of the metal recovery system using the third embodiment described above, a column-like or cartridge-like reaction vessel 21 can be adopted. As a result, when the column-shaped or cartridge-shaped reaction tank 21 is employed, the reaction tank 21 can also function as the silicon storage tank 23.

  In addition, since the other structure of the above-mentioned 3rd Embodiment is the same as that of each structure of the metal collection | recovery system using the above-mentioned 1st Embodiment, description is abbreviate | omitted.

(Solution reuse method and solution reuse system)
Since each embodiment of the solution reuse method and the solution reuse system has the same basic principle and configuration as those of the above-described metal recovery method, recovery apparatus, or recovery system, the differences are as follows. In the following.

<Fifth Embodiment>
The configuration of the solution reuse system of the present embodiment uses solid-liquid separation means instead of the recovery unit 12 that recovers metal in FIG. In the fifth embodiment, since the first solution used for processing can regenerate a solution containing metal, the discharge unit 16 of the mixing / deposition processing unit 10 is connected to solid-liquid separation means (not shown). . A solution obtained by solid-liquid separation (also referred to as “third solution”) can be reused. The regeneration means used in the regeneration step is not particularly limited. For example, the regeneration means may include adding a necessary electrolytic substance or diluting with water. The regenerated solution can be used again as the first solution.

<Sixth Embodiment>
As another example of the configuration of the solution reuse system of the present embodiment, a configuration similar to the configuration of the second embodiment or the fifth embodiment may be employed as the reuse system of the present embodiment.

<Seventh Embodiment>
As another example of the configuration of the solution reuse system of the present embodiment, a configuration similar to the configuration of the third embodiment or the fifth embodiment may be employed as the reuse system of the present embodiment.

<Eighth Embodiment>
The solution reuse system in the present embodiment is the same as the metal recovery system described above and the fifth to seventh embodiments described above. Therefore, only different points will be described.

  The solution reuse system in the present embodiment includes an electrolytic treatment apparatus 26 instead of the solution generation tank 24 shown in FIG. Further, the metal recovered in the metal recovery unit 12 includes not only valuable metals such as precious metals but also metals that cannot be discarded in a state of being contained in a solution after electrolytic treatment such as copper. The liquid after the recovery process is performed in the metal recovery unit 12 is solid-liquid separated into recovered metal and waste liquid.

[Example]
From the examples shown below, the present inventors have obtained the knowledge that it is possible to recover quickly and in large quantities by adopting the basic first solution. Some specific examples are as follows. The above-described embodiments are not limited to the following examples.

Example 1
Specifically, using each of the above-described embodiments (typically, the recovery device 100 having the configuration shown in FIG. 1), the mixing / precipitation processing unit 10 maintained at a liquid temperature of 25 ° C. (298 K) in a thermostatic bath, A metal ion solution containing a noble metal and / or copper (first solution) and silicon powder were mixed. After mixing, stirring was continued at 200 rpm. The first solution for each treatment time is collected, and after filtration, in the first solution using ICP emission spectroscopic analysis (device name: Hitachi High-Technologies Corporation (former Seiko Instruments Inc.), model SPS7800) The recovery rate was determined by measuring the metal concentration (concentration of residual metal).

Standard conditions are as follows.
(1) Supply amount of silicon powder having an average particle size of 45 μm or less 5.6 g / L (0.2 M)
However, only for the recovery of palladium, the supply amount is 11.2 g / L (equivalent to 0.4M).
(2) Temperature of the solution (298K)
However, the temperature is 340K only for the recovery of palladium.
(3) Stirring speed (200 rpm))
In this example, sodium hydroxide was employed as an agent for making the first solution basic. A typical example of a drug for making the first solution basic is sodium hydroxide or potassium hydroxide.

  In addition, recovery of each metal from an aqueous solution in which gold, silver, copper, palladium, and platinum salts were dissolved individually as the metal species in the first solution in Example 1 was evaluated. In this evaluation, the solution was collected at each reaction time, and after filtration, the recovery rate was determined by measuring the residual concentration of noble metal or copper in the first solution by ICP emission spectroscopy.

  For example, the gold recovery rate was calculated using the following formula.

The metal salt employed in this example is Au: HAuCl ₄ , Pt: H ₂ PtCl ₆ , Cu: CuCl ₂ , Pd: PdCl ₂ , Ag: AgNO ₃ . In addition, the solution (1st solution) of the metal ion containing a noble metal and / or copper can also contain a well-known complexing agent. This has an effect of preventing with high accuracy that the metal to be recovered is precipitated as a precipitate before being recovered using silicon. Further, even in a solution containing a complexing agent, it is possible to sufficiently recover noble metal and / or copper in substantially the same manner as a solution containing no complexing agent. I can say that.

The metal ion concentration and pH value used in the experiment are shown below.
Au: about 197 mg / L (about 1 mM), pH value about 11
Pt: about 195 mg / L (about 1 mM), pH value about 13
Cu: about 66 mg / L (about 1 mM), pH value about 13
Pd: about 59 mg / L (about 0.6 mM), pH value about 13
Ag: about 21 mg / L (about 0.2 mM), pH value about 13

  As a result, it has been clarified that by adopting the first basic solution, sufficient recovery ability can be exhibited for various metals. The results examined in more detail are as follows.

  FIG. 6 is a graph showing the recovery of gold for each processing time from the first solution containing gold (Au) ions. FIG. 7 is a graph showing the recovery of platinum for each treatment time from the first solution containing platinum (Pt) ions. The unit of time on the horizontal axis in FIGS. 6 and 7 and FIGS. 8 to 10 to be described later is “minute (min.)”.

  First, as shown in FIG. 6, it can be seen that substantially 100% of the gold is recovered at a stage after 180 minutes have elapsed since the start of the process. More specifically, the initial gold (Au) concentration was about 197 mg / L (about 1 mM), but already about 80% or more after 120 minutes from the introduction or contact with the silicon powder. The gold (Au) concentration after a lapse of 180 minutes at the latest decreased to 0.19 mg / L or less. That is, it is worthy to note that at the stage after 180 minutes, the recovery rate was 99% or more, more specifically 99.9% or more, and more specifically about 99.91% or more. Therefore, in this example as well, it has been clarified that by adopting the basic first solution, an excellent metal recovery capability can be exhibited. In addition, the 1st solution of the Example shown in FIG. 6 contained 5 mM sodium hydroxide, and the pH value was about 11.

  Next, as shown in FIG. 7, it can be seen that about 30% of platinum is recovered at a stage 200 minutes after the start of the treatment. Moreover, it became clear that 60% or more of platinum can be recovered at a stage after 1140 minutes (24 hours) from the start of the treatment. Accordingly, it has been clarified that by adopting the basic first solution, an excellent metal recovery capability can be exhibited. In addition, the 1st solution of the Example shown in FIG. 7 contained 0.15 mol / L (mol per liter) sodium hydroxide, and the pH value was about 13.

  On the other hand, separation and recovery of precious metals (for example, gold and platinum) can be realized from the results of FIGS. That is, under conditions that do not intentionally improve the platinum recovery rate (for example, conditions under which the amount of silicon input is changed, conditions under which the processing temperature is changed, and / or conditions under which the pH value of the first solution is changed). A specific metal is selectively or preferentially recovered from the first solution containing each ion of platinum and platinum by preferentially sending only the silicon on which gold is deposited to the discharge section (for example, the discharge section 16). The method and apparatus are one preferred embodiment that can be employed. In the above example, the recovery rate of gold and platinum is described, but in the above example, each of the above metal elements (group of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium are described. The first solution containing ions of two or more elements selected from the above can also be applied.

  FIG. 8 is a graph showing the recovery of copper for each processing time from the first solution containing copper (Cu) ions. In addition, FIG. 9 is a graph showing the recovery of palladium for each treatment time from the first solution containing palladium (Pd) ions. In addition, FIG. 10 is a graph showing the recovery of silver for each processing time from the first solution containing silver (Ag) ions.

  As shown in FIG. 8, it can be seen that substantially 100% of copper has been recovered at the stage after 60 minutes from the start of the treatment. On the other hand, as shown in FIG. 9, it can be seen that substantially 100% of palladium is recovered at a stage after only 4 minutes from the start of the treatment. In addition, as shown in FIG. 10, about 95% or more of silver has already been recovered at the stage after 20 minutes from the start of processing, and substantially 100% of silver has been recovered at the stage after 30 minutes. I understand. The first solutions in the examples shown in FIGS. 8 to 10 all contain 100 mM sodium hydroxide. The pH value of the first solution in each example is as described above.

  Therefore, it has been clarified that, in each of the above-described examples, by adopting the basic first solution, an excellent metal recovery ability can be exhibited. The temperature of the first solution employed in the example of the recovery of palladium (Pd) shown in FIG. 9 was 340K, but even if the temperature is about room temperature (298K), for example, An effect can be produced.

  In addition, about the collection | recovery of copper, even if it is a case where what is called industrial waste liquid (copper waste liquid) containing organic substances, such as a resin component, is used as a sample in another Example which the present inventors performed, from the start of a process. It was confirmed that about 43% or more of copper could be recovered at the stage after 60 minutes. Therefore, in this example as well, it has been clarified that by adopting the basic first solution, an excellent metal recovery capability can be exhibited.

  Further, by adopting a basic first solution containing ions of at least one element selected from the group of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium, the accuracy is increased. It can recover metal quickly and in large quantities.

  In any of the above-described examples, the metal obtained as a result of the recovery is an extremely fine metal particle (typically, a metal particle having a particle size on the order of nanometers). It became clear. Therefore, it is worthy of special mention that the devices, systems, and / or methods of the above-described embodiments are utilized from the viewpoint of manufacturing metal particles (in other words, extremely fine metal particles).

  The disclosure of each of the above-described embodiments is described for explaining the embodiments, and is not described for limiting the present invention. In addition, modifications that exist within the scope of the present invention including other combinations of the embodiments are also included in the scope of the claims.

  INDUSTRIAL APPLICABILITY The present invention can be used in a wide range of industrial fields including the recycling industry as a specific metal recovery method, metal recovery device, metal recovery system, and solution recycling method.

Claims (4)

Contacting a basic first solution containing ions of at least one element selected from the group of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium with particulate silicon; A deposition step of depositing a metal comprising the element on the silicon;
A recovery step of recovering the metal composed of the element deposited on the silicon,
Metal recovery method. Reaction in which a basic first solution containing ions of at least one element selected from the group consisting of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium is contacted with particulate silicon A tank,
A recovery unit for recovering a metal composed of the element deposited on the silicon,
Metal recovery device. The metal recovery device according to claim 2,
A discharge part for discharging the mixed solution of the first solution and the silicon in the reaction tank in contact with each other from the reaction tank;
Solid-liquid separation means for solid-liquid separation of the discharged mixed liquid;
The recovery unit for recovering the metal composed of the element deposited on the separated silicon,
Metal recovery system. Contacting a basic first solution containing ions of at least one element selected from the group of gold, silver, copper, palladium, rhodium, platinum, iridium, ruthenium, and osmium with particulate silicon; A deposition step of depositing a metal comprising the element on the silicon;
A recovery step of recovering the metal composed of the element deposited on the silicon;
In the recovery step, by bringing into contact with a metal recovery solution that dissolves the silicon on which the metal consisting of the element is deposited, a particulate metal consisting of the element is generated.
A method for producing metal particles.

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