JP7046352B2 - Precious metal concentrating method and precious metal concentrator - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Law (1) General Incorporated Association Resources and Materials Society, Resources and Materials & EARTH2017 (Sapporo), August 24, 2017, Website https: // confit. atlas. jp / guide / print / mij2017b / subject / 3401-09-01 / detail (2) General Incorporated Association Resources and Materials Society, Conference Program / Abstracts / Resources / Materials & EARTH2017 (Sapporo), September 26, 2017, Page 162 (3) Japan Society for Resources and Materials, Resources and Materials & EARTH2017 (Sapporo), September 26, 2017, website https://confit. atlas. jp / guide / event / mmij2017b / subject / 3401-09-01 / advanced

The present invention relates to a noble metal concentrating method and a noble metal concentrating device, and more particularly to a noble metal concentrating method for concentrating and recovering a noble metal such as gold contained in used electric / electronic equipment.

Precious metals generally refer to the eight elements of gold (Au), silver (Ag), platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), and osmium (Os). Copper is included as the precious metal, based on the magnitude of the ionization tendency relative to hydrogen.

Among the above precious metals, for example, for hydrometallurgy of gold, a method of dissolving gold contained in used electronic components with aqua regia to separate gold from the used electronic components has been put into practical use. However, with this method, it is considered difficult to efficiently recover the gold wired inside the resin. Further, regarding dry refining, a method is disclosed in which a raw material containing a metal is heated in a chlorine stream and volatilized by chloride, and a solid carbon is mixed to lower the volatilization temperature to separate and recover gold. (Patent Document 1). Further, it is said that when gold is heated to 800 ° C. or higher in a chlorine stream, gold volatilizes at a high volatilization rate (Non-Patent Document 1).

On the other hand, as a metal concentration method, the present inventors reduced the first solid metal compound in the mixture containing an oxide of a specific rare metal such as gallium at the first content to obtain a gaseous metal compound. We have found a dry concentration method for oxidizing the gaseous metal compound and concentrating the second solid metal compound as a second solid metal compound at a second content higher than the first content (Patent Document 2).

Japanese Unexamined Patent Publication No. 2015-17279 Japanese Patent No. 6192645

Akira Hosoi, Kenichi Hirata, Yasushi Takasaki, Atsushi Shibayama, "Recovery of Metals from Waste Electronic Substrates Using Chloride Volatilization Method and Examination of Volatile Behavior", Japan Institute of Metals, Vol. 76, No. 2, 2012, No. 155 Page-163

It is considered that the metal concentration method having a small environmental load as in Patent Document 2 can be applied to the concentration of precious metals such as gold.

An object of the present invention is to provide a noble metal concentrating method and a noble metal concentrating device capable of concentrating a noble metal with a small environmental load.

As a result of diligent research on the concentration of gold, which has a small environmental load, the present inventors have found a first solid metal compound in a mixture containing an oxide of a specific rare metal such as gallium at a first content. In a method of reducing the gaseous metal compound to obtain a gaseous metal compound and oxidizing the gaseous metal compound to concentrate the second solid metal compound as a second solid metal compound at a second content higher than the first content, the noble metal is added to the mixture. It has been found that the noble metal can be concentrated at a higher content than the content in the mixture when it is contained.

That is, the gist structure of the present invention is as follows.
(1) Gas noble metal by vaporizing the first solid noble metal in a mixture of the first solid noble metal containing one or more kinds of noble metals selected from the group consisting of gold, silver and copper at the first metal content. And the process of
A step of solidifying the gaseous noble metal and collecting the second solid noble metal as a second solid noble metal with a second metal content higher than that of the first metal content.
Precious metal concentration method.
(2) The mixture contains a first solid metal compound containing a metal selected from the group consisting of gallium, indium, germanium, tellurium, and cesium at a third metal content.
The step of vaporizing the first solid noble metal to obtain the gaseous noble metal is carried out together with the step of reducing the first solid metal compound in the mixture to form a gaseous metal compound.
In the step of collecting the second solid noble metal at the second metal content, the gas metal compound is oxidized to obtain the second solid metal compound as the second solid metal compound, and the second solid metal compound is higher than the third metal content. The noble metal concentration method according to (1) above, which is performed together with the step of collecting by the metal content.
(3) The precious metal concentration method according to (1) or (2) above, wherein the mixture contains used electronic devices.
(4) The gas noble metal is obtained by vaporizing the first solid noble metal in the mixture of the first solid noble metal containing one or more kinds of noble metals selected from the group consisting of gold, silver and copper at the first metal content. The present invention is characterized by comprising a reaction furnace in which the gaseous noble metal is solidified and the second solid noble metal is collected as a second solid noble metal at a second metal content higher than that of the first metal content. Precious metal concentrator.
(5) The reactor is
A reaction tube for reacting the first solid noble metal in the internal space,
A heating unit that heats the reaction tube and
A holding portion provided in the lower part of the reaction tube and holding the first solid noble metal, and a holding portion.
An introduction port provided in the lower part of the holding part and for introducing the introduction gas from the lower part of the reaction tube into the holding part.
A fluidized bed portion provided above the holding portion and allowing the first solid noble metal to flow by the pressure of introducing the introduced gas into the holding portion.
A collecting section located above the fluidized bed and collecting the second solid noble metal, and a collecting section.
The noble metal according to (4) above, which is provided above the collecting portion and has a discharge port for discharging by-product gas generated in the reaction furnace from the inside of the reaction tube to the outside. Concentrator.
(6) The precious metal concentrator according to (5) above, wherein the collecting portion is a part of a side wall defining an internal space of the reaction tube.
(7) The precious metal concentrator according to any one of (4) to (6) above, wherein the mixture contains used electric / electronic equipment.

According to the present invention, the noble metal can be concentrated without adding harmful substances such as aqua regia and chlorine gas to the mixture containing the noble metal. Therefore, it is possible to reduce the environmental load and concentrate precious metals such as gold from primary resources such as ore and secondary resources such as used electric / electronic equipment (so-called urban ore). In particular, when recycling used electric / electronic equipment, precious metals contained in the used electric / electronic equipment can be easily concentrated.

It is a figure which shows roughly the structure of the noble metal concentrator to which the noble metal concentrating method which concerns on embodiment of this invention is applied. It is sectional drawing which shows the structure of the reactor in FIG. It is sectional drawing which shows the structure of the collection part and the recovery device of the reaction furnace in FIG. It is a graph explaining the oxygen partial pressure dependence of the gallium type vapor pressure concentrated by the noble metal concentrator of FIG. It is a figure explaining the height from the upper end part of the through hole to the collection part in a reaction tube. It is a graph which shows the relationship between the height from the upper end part of the through hole to the collection part in a reaction tube, and the yield of solid gallium oxide. It is a graph which shows the temperature distribution along the height direction in a reaction tube when the temperature in a furnace is constant. It is a figure which shows the relationship between the flow rate of nitrogen gas which is an example of the reducing gas supplied to a reaction furnace, and the yield of solid gallium oxide. It is a figure which shows the relationship between the temperature in a furnace in a reactor, and the yield of solid gallium oxide. It is a graph which shows the relationship between the temperature of a collecting part and a yield when the temperature in a furnace is kept constant. It is sectional drawing which shows the 1st modification of the reactor of FIG. It is sectional drawing which shows the 2nd modification of the reaction furnace of FIG. It is a figure which shows roughly the structure of the metal compound concentrator which concerns on 2nd Embodiment of this invention. It is a figure which shows roughly the structure of the metal compound concentrator which concerns on 3rd Embodiment of this invention. It is a figure explaining the recycling model of the precious metal realized by using the precious metal enrichment method which concerns on this embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<Structure of precious metal concentrator>
FIG. 1 is a diagram schematically showing a configuration of a noble metal concentrating device to which the noble metal concentrating method according to the embodiment of the present invention is applied. The apparatus configuration of FIG. 1 shows an example thereof, and the configuration to which the noble metal concentration method according to the present invention is applied is not limited to that of FIG.

The noble metal concentrating device 1 of FIG. 1 is a device for concentrating a mixture containing a noble metal by a dry method, and one or more kinds of noble metals selected from the group consisting of gold, silver and copper are concentrated in the first metal content. The first solid noble metal in the mixture of the first solid noble metal contained is vaporized to be a gaseous noble metal, and the gaseous noble metal is solidified to be a second solid noble metal, and the second solid noble metal is obtained from the first metal content. Also equipped with a reactor 10 that collects at a high secondary metal content. In this precious metal concentrator 1, as a configuration other than the reaction furnace 10, for example, an oxygen-containing gas supply means 40, a gas heating means 50, and a reducing gas generation means 30 are provided on the upstream side of the reaction furnace 10 as a reference. A gas discharge means 60, a recovery means 80, and a purification means 90 are arranged on the downstream side of the reactor 10.

The noble metal concentrated by the noble metal concentrator 1 may contain one or more kinds of metal elements selected from the group consisting of gold (Au), silver (Ag) and copper (Cu), and each of them may contain an element of one or more kinds of metals. Includes simple metals, alloys or compounds. For example, when the precious metal is gold, it includes pure gold, an alloy of gold, or a compound of gold.

As shown in FIG. 2, the reaction furnace 10 is provided with a reaction tube 11 for reacting the first solid noble metal in the internal space, a heating unit 12 for heating the reaction tube 11, and a lower portion in the reaction tube 11. A holding portion 13 for holding the first solid noble metal, an introduction port 14 provided below the holding portion 13 for introducing the introduction gas into the holding portion 13 from the lower part of the reaction tube 11, and above the holding portion 13. The fluidized bed portion 15 that causes the first solid noble metal to flow by the pressure of introducing the introduced gas into the holding portion 13, and the collecting unit 16-that is located above the fluidized bed portion 15 and collects the second solid noble metal. It has 1 and a discharge port 17 provided above the collection unit 16-1 for discharging the by-product gas generated in the reaction furnace 10 from the inside of the reaction tube 11 to the outside.

Further, the noble metal concentrator 1 also has a function of concentrating a metal compound such as a rare metal. Specifically, the noble metal concentrator 1 is a metal selected from the group consisting of gallium (Ga), indium (In), germanium (Ge), tellurium (Te), and cesium (Cs) (hereinafter, simply "rare metal"). The first solid metal compound in the mixture M of the first solid metal compound containing (also referred to as) the first metal content is reduced to a gaseous metal compound, and the gaseous metal compound is oxidized to the second. As a solid metal compound, a reaction furnace 10 for collecting the second solid metal compound at a second metal content higher than the first metal content and a reducing gas G2 for reducing the first solid metal compound are generated and reacted. The reducing gas generating means 30 supplied to the furnace 10, the oxygen-containing gas supplying means 40 supplying the oxygen-containing gas G1 for generating the reducing gas G2 to the reducing gas generating means 30, and the gas heating for heating the oxygen-containing gas G1. Means 50, a gas discharging means 60 for discharging the by-product gas G3 generated in the reaction furnace 10, a recovery means 80 arranged downstream of the gas discharging means 60 and recovering the second solid metal compound, and recovery. It is arranged downstream of the means 80 and includes a purification means 90 for purifying the by-product gas G3.

As shown in FIG. 2, the reaction furnace 10 is provided with a reaction tube 11 for reacting the first solid metal compound in the internal space, a heating unit 12 for heating the reaction tube 11, and a lower portion in the reaction tube 11. In order to introduce the holding portion 13 for holding the first solid metal compound and the reducing gas G2 provided in the lower part of the holding portion 13 and supplied from the reducing gas generating means 30 into the holding portion 13 from the lower part of the reaction tube 11. A flow bed portion 15 provided above the holding portion 13 and flowing the first solid noble metal and / or the first solid metal compound by the pressure of supplying the reducing gas G2 to the holding portion 13. The by-product gas G3 is located above the floor portion 15 and is provided above the collection unit 16-1 for collecting the second solid noble metal and / or the second solid metal compound and the collection unit 16-1. It has a discharge port 17 for discharging the gas from the inside of the reaction tube 11 to the outside. From the viewpoint that the first solid noble metal and / or the first solid metal compound can be heated directly or locally at a high temperature, it is preferable to use an infrared furnace such as an infrared gold image furnace as the reaction furnace 10. In addition to the infrared furnace, a resistance heating furnace, a gas furnace, an induction heating furnace, a direct energization heating furnace, or the like may be used.

The reaction tube 11 closes the inner tube 11a, the support tube 11b that supports the inner tube 11a, the outer tube 11c that internally accommodates both the inner tube 11a and the support tube 11b, and the lower end opening of the outer tube 11c. It has a portion 11d, a closing portion 11e that closes the upper end opening of the outer pipe 11c, and a supply portion 11f provided in the outer pipe 11c for supplying the mixture M into the inner pipe 11a. The mixture M is a material containing a first solid noble metal containing a noble metal selected from the group consisting of gold, silver and copper at a first metal content.

The mixture M may contain a carbon source in addition to the noble metal, and is, for example, a used electric / electronic device containing the noble metal and the resin, and specifically, an LED device. When the mixture M is an LED device, examples of the precious metal include gold used for bonding wires and the like, and silver and copper used for printed circuit boards and lead frames. Examples of the resin include epoxy resins, silicone resins, polyimide resins and the like used for the base material of the printed circuit board.

Further, the above-mentioned mixture M is a metal selected from the group consisting of gallium (Ga), indium (In), germanium (Ge), tellurium (Te), and cesium (Cs) (hereinafter, also simply referred to as “rare metal”). May contain a first solid metal compound containing a third metal content. For example, when the mixture M is the used electric / electronic device, the used electric / electronic device may include an LED element containing the rare metal. It is possible to concentrate the precious metal and the rare metal even when the mixture M further contains the rare metal as described above in addition to the precious metal.

The inner tube 11a is made of a tubular body having one end closed, and has a tubular portion 11a-1, an inner peripheral surface 11a-2 of the tubular portion 11a-1, and a bottom portion 11a-provided integrally with the tubular portion 11a-1. 3 and a through hole 11a-4 provided in the bottom portion 11a-3. The inner tube 11a is made of a ceramic whose main component is an oxide such as aluminum, magnesium, zirconia, or quartz. Of the internal space defined by the tubular portion 11a-1 and the bottom portion 11a-3, the internal space on the bottom portion 11a-3 side forms the holding portion 13, and the internal space located directly above the holding portion 13 forms the fluidized bed portion 15. Eggplant.

The support pipe 11b is interposed between the inner pipe 11a and the closing portion 11d, positions the inner pipe 11a in the outer pipe 11c in the height direction, and communicates the introduction portion 14 and the inner pipe 11a. .. The support tube 11b is made of a ceramic whose main component is an oxide such as aluminum, magnesium, zirconia, or quartz. The outer tube 11c is made of a tubular body having both upper and lower ends open, and is made of a ceramic whose main component is an oxide such as aluminum, magnesium, zirconia, or quartz.

The closed portion 11d has a through hole 11d-1 penetrating in the vertical direction, and the through hole 11d-1 is connected to the gas introduction pipe 30a of the gas generating means 30. The upper end of the through hole 11d-1 forms the introduction port 14 described above.

The closed portion 11e has a through hole 11e-1 penetrating in the vertical direction, and the through hole 11e-1 is connected to the gas discharge pipe 60a of the reducing gas discharge means 60. The lower end of the through hole 11e-1 forms the above-mentioned discharge port 17.

The supply unit 11f is, for example, a supply pipe for supplying the mixture M from the outside into the inner pipe 11b, and a lid portion 11g for sealing the inside of the outer pipe 11c is attached to the end of the supply pipe. There is. The supply unit 11f may have a transport means for transporting the mixture M and a gate portion for maintaining a closed state in the furnace.

The heating unit 12 has a furnace body 12a and a heater 12b mounted in the furnace body 12a. The furnace body 12a has a heat insulating material containing ceramic as a main component, and insulates the internal space and the outside of the furnace body 12a. The heater 12b is, for example, an alloy heating element such as iron-chromium (Fe-Cr) or nickel-chromium (Ni-Cr), a single metal heating element such as molybdenum (Mo) or tungsten (W), or carbonization. It is made of a non-metal heating element such as silicon (SiC). The heating unit 12 may have a temperature detection unit such as a thermocouple and a control unit that controls the calorific value of the heater 12b based on the detection temperature of the temperature detection unit. In this case, the heating unit 12 may have a temperature detection unit in the furnace body 12a. The temperature inside the reaction tube 11 is adjusted by controlling the temperature.

The holding unit 13 holds the mixture M of the first solid noble metal containing the noble metal at the first metal content. Before introducing the gas or in the initial stage of heating, a plug member made of Parafilm may be fitted into the through hole 11a-4 provided in the bottom portion 11a-3. This makes it possible to prevent the mixture M in the holding portion 13 from falling from the through holes 11a-4.

The fluidized bed portion 15 is a space in which particles made of the first solid metal compound contained in the mixture M flow due to the pressure of supplying the reducing gas G2 to the holding portion 13. At this time, a loop-shaped flow path L as shown in FIG. 2 is formed in the fluidized bed portion 15. Then, in the fluidized bed portion 15, the first solid noble metal constituting the fluidized particles is vaporized and changed to a gaseous noble metal, and further, the gaseous noble metal is solidified and changed to a second solid noble metal.
Further, in the fluidized bed portion 15, the first solid metal compound constituting the fluidized particles can be changed to a gaseous metal compound by a reduction reaction, and further, the gaseous metal compound can be transformed into a second solid metal compound by an oxidation reaction.

The collection unit 16-1 is, for example, a part of the side wall defining the internal space of the reaction tube 11. Specifically, the collecting portion 16-1 is a region located above the fluidized bed portion 15 in the inner peripheral surface 11a-2 of the tubular portion 11a-1 in the reaction tube 11. The collecting unit 16-1 collects the second solid noble metal obtained by solidifying the gaseous noble metal with a second metal content higher than that of the first metal content.
Further, the collecting unit 16-1 can collect the second solid metal compound obtained by oxidizing the gaseous metal compound at a fourth metal content higher than the third metal content. In the fluidized bed portion 15, when the gas metal compound of the rare metal is changed to the second solid metal compound by the oxidation reaction as described above, the second solid metal compound is formed on the inner peripheral surface 11a-2 of the inner tube 11a by this oxidation reaction. It adheres and the second solid metal compound is collected.

The oxygen-containing gas supply means 40 (FIG. 1) supplies, for example, the oxygen-containing gas G1 to the gas heating means 50 at a predetermined flow rate. The oxygen-containing gas G1 supplied by the oxygen-containing gas supply means 40 is, for example, an oxygen-containing nitrogen gas such as air. The oxygen-containing gas supply means 40 may be a blower for supplying air, or has a nitrogen gas generating means and a fan, and a mixed gas of nitrogen and air, or an impurity oxygen of about 1 ppm to 1%. The nitrogen gas contained may be supplied to the gas heating means 50.

In the present embodiment, the gas heating means 50 is a heat exchanger 50 having a first flow path 50-1a connected to the oxygen-containing gas supply means 40 and a second flow path 50-1b connected to the gas discharge means 60. It has a -1 and a preheating unit 50-2 that heats the oxygen-containing gas G1 supplied from the first flow path 50-1a to a predetermined temperature and supplies the oxygen-containing gas G1 to the reducing gas generating means 30.

In the heat exchanger 50-1, the oxygen-containing gas G1 flows through the first flow path 50-1a, and the by-product gas G3 having a higher temperature than the oxygen-containing gas G1 flows through the second flow path 50-1b. At this time, heat energy is exchanged between the oxygen-containing gas G1 in the first flow path 50-1a and the by-product gas G3 in the second flow path 50-1b, and the heat energy is exchanged in the first flow path 50-1a. The oxygen-containing gas G1 is heated by the by-product gas G3 in the second flow path 50-1b, and the by-product gas G3 is cooled by the oxygen-containing gas G1.

The preheating section 50-2 has a stainless steel tube 50-2a connected to the first flow path 50-1a and a heating section 50-2b for heating the stainless steel tube 50-2a, and has a first flow path. The oxygen-containing gas G1 supplied from 50-1a is heated in the stainless steel pipe 50-2a, and the heated oxygen-containing gas G1 is supplied to the reducing gas generation means 30 via the gas introduction pipe 50a. The preheating unit 50-2 may have a temperature detection unit such as a thermocouple and a control unit that controls the calorific value of the heating unit 50-2b based on the detection temperature of the temperature detection unit. In this case, the control unit adjusts the temperature of the oxygen-containing gas G1 supplied to the reactor 10 by controlling the temperature inside the stainless steel tube 50-2a.

The reducing gas generating means 30 has a material supply unit 31 for supplying the carbon source-containing material W to the generation unit described later, and a generation unit 32 for oxidizing the carbon source-containing material W to generate the reduced gas G2. The material supply unit 31 is, for example, a supply path capable of supplying the carbon source-containing material W to the generation unit 32 from the outside.

The generation unit 32 has, for example, a quartz tube 32a connected to the preheating unit 50-2 and a heater 32b for heating the quartz tube 32a. A heating unit such as a ribbon heater is attached to the gas introduction pipe 30a connecting the reducing gas generating means 30 and the reaction furnace 10. The generation unit 32 heats the oxygen-containing gas G1 supplied from the preheating unit 50-2 and the carbon source-containing material W supplied from the material supply unit 31 with the heater 32b, and contains carbon monoxide by the carbon oxidation reaction. The reducing gas G2 is generated and supplied to the reactor 10 via the gas introduction pipe 30a.

The carbon source-containing material W supplied to the reducing gas generating means 30 is, for example, a petroleum-based liquid fuel, waste lumber or waste resin, or a mixture thereof. From the viewpoint of recycling, the carbon source-containing material W is preferably a waste resin obtained by decomposing used electric / electronic equipment.
Further, the reducing gas G2 generated by the reducing gas generating means 30 is, for example, a combustion gas of a petroleum-based liquid fuel, a combustion gas of a waste timber, or a combustion gas of a waste resin, and specifically, for example, carbon monoxide ( It is a mixed gas containing CO), carbon dioxide (CO ₂ ) and nitrogen (N ₂ ).
The carbon source-containing material W may contain an oxidation catalyst. The oxidation catalyst contained in the carbon source-containing material W is, for example, a precious metal catalyst such as platinum (Pt), palladium (Rd), rhodium (Rh), and silver (Ag). This noble metal catalyst may be used in a state of being supported on a carrier made of a porous oxide such as alumina (Al ₂ O ₃ ), or a cerium oxide-zirconium oxide-based composite oxidation such as a CeO2 _{- ZrO2} solid solution. It may be used in a state of being supported on a carrier made of a substance. As a result, the carbon in the carbon source-containing material W can be oxidized at a low temperature.

The gas discharge means 60 has a gas discharge pipe 60a whose upstream side is connected to the reaction furnace 10 and whose downstream side is connected to the purification means 90, and discharges the by-product gas G3 discharged from the reaction furnace 10 to generate heat. It is supplied to the purification means 90 through the exchanger 50-1.

The recovery means 80 is attached in the path of the gas discharge pipe 60a connecting the reactor 10 and the heat exchanger 50-1. The collecting means 80 is, for example, a dust collector. The recovery means 80 is connected to a centrifugal separation type separation unit 81 that separates the second solid metal compound in the by-product gas G3 by centrifugal force, and a second solid that is connected below the separation unit 81 and separated by the separation unit 81. It has a recovery unit 82 for recovering a metal compound.

The purification means 90 is located downstream of the gas discharge means 60 and downstream of the heat exchanger 50-1, purifies the by-product gas G3 supplied from the recovery means 80, and uses the purification gas G4 as an apparatus. Discharge to the outside. The purification means 90 is, for example, activated carbon, and carbon monoxide in the by-product gas G3 is removed by adsorbing carbon monoxide in the by-product gas G3 on the activated carbon. The purification means 90 has one or more catalysts that convert carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NO _X ), etc. in the by-product gas G3 into harmless substances. May be. For example, carbon monoxide in the by-product gas G3 is converted to carbon dioxide, hydrocarbons are converted to water and carbon dioxide, and nitrogen oxides are converted to nitrogen. When the by-product gas G3 does not contain carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NO _X ) or the like, the purification means 90 may not be provided.

<Precious metal concentration method>
In the noble metal concentrator 1 having the above configuration, the noble metal is concentrated by an extremely simple method. That is, the gas noble metal is obtained by vaporizing the first solid noble metal in the mixture M of the first solid noble metal containing one or more kinds of noble metals selected from the group consisting of gold, silver and copper at the first metal content. Then, the gaseous noble metal is solidified to be used as a second solid noble metal, and the second solid noble metal is collected at a second metal content higher than that of the first metal content. It is presumed that such concentration of the noble metal occurs because, for example, the carbon source contained in the mixture M is calcined in the fluidized bed portion 15 to satisfy the conditions for vaporizing or evaporating the solid noble metal.

In the step of vaporizing the first solid noble metal into a gaseous noble metal, for example, the reduction reaction conditions of the first solid metal compound (solid gallium nitride or the like) can be included or the same conditions can be used. The temperature condition for heating the mixture M, particularly the temperature condition for vaporizing the first solid noble metal, can be 900 ° C. or higher and 1500 ° C. or lower.
From the viewpoint of increasing the yield of gold, the temperature condition for heating the mixture M, particularly the temperature condition for vaporizing the first solid noble metal, can be more than 1300 ° C and not more than 1500 ° C. From the viewpoint of increasing the yield of silver, the temperature condition for heating the mixture M, particularly the temperature condition for vaporizing the first solid noble metal, can be 900 ° C. or higher and 1100 ° C. or lower. From the viewpoint of increasing the yield of copper, the temperature condition for heating the mixture M, particularly the temperature condition for vaporizing the first solid noble metal, can be 1100 ° C. or higher and 1300 ° C. or lower. Further, even in the step of collecting the second solid noble metal at a second metal content higher than that of the first metal content, for example, the same conditions as the oxidation reaction conditions of the first solid metal compound can be set.

In this concentration method, the ratio of the mass of one or more of the noble metal elements (for example, gold) in the first solid noble metal to the mass of the mixture M containing the first solid noble metal is the first metal content α1. When the ratio of the mass of the noble metal element in the second solid noble metal to the mass of the second solid noble metal is the second metal content α2, the second metal content α2 is higher than the first metal content α1. Further, when the mass of the noble metal element in the first solid noble metal contained in the mixture M is m1, and the mass of the noble metal element in the second solid noble metal collected by the collecting unit 16-1 is m2, the amount is collected. The rate β (= m2 / m1 * 100) is 0.5% or more, preferably 0.8% or more. When the noble metal element is silver, the yield β is 3.0% or more, preferably 8.0% or more. When the noble metal element is copper, the yield β is 5.0% or more, preferably 8.0% or more.

Further, when the mixture M contains a first solid metal compound containing a metal selected from the group consisting of gallium, indium, germanium, tellurium, and cesium at a third metal content, the first solid noble metal is vaporized. The step of converting the gas noble metal into a gaseous noble metal may be performed together with, for example, a step of reducing the first solid metal compound in the mixture M to form a gaseous metal compound. Further, in this case, in the step of collecting the first solid noble metal at the second metal content, for example, the second solid metal compound is obtained by oxidizing the gaseous metal compound as the second solid metal compound. It may be carried out together with the step of collecting at a fourth metal content higher than the metal content. By the above-mentioned noble metal concentration method, one or more kinds of the above-mentioned noble metals can be easily concentrated.

Next, the first solid metal compound is a first solid gallium compound (solid gallium nitride or solid gallium oxide), a first solid indium compound, a first solid germanium compound, a first solid tellurium compound, or a first solid cesium compound. The method for concentrating the metal compound in the above case will be described in the following (1-1) to (1-6).

(1-1) When the first solid metal compound is the first solid gallium compound (solid gallium nitride) and the second solid metal compound is the second solid gallium compound (solid gallium oxide) In FIG. 2, first, the reaction furnace 10 is used. A mixture M containing gallium nitride, which is a first solid metal compound, at a third metal content is charged from the supply unit 11f of the above, and the mixture M is housed in the holding unit 13. When the mixture M is a rare metal-containing waste material, it is, for example, a mixture of gallium nitride (GaN) and aluminum oxide (Al ₂ O ₃ ), and if necessary, a mixture to which activated carbon (C) is further added. For example, when the mixture M is an ore, in addition to the first solid gallium compound, silicon dioxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), magnesium oxide (MgO), calcium oxide (CaO), iron oxide (Fe). It is a mixture containing ₂ O ₃ ) and the like. After that, the carbon source-containing material W, for example, an epoxy resin is put into the material supply unit 31 of the reducing gas generating means 30, and the carbon source-containing material W is housed in the quartz tube 32a.

Next, the oxygen-containing gas G1 is introduced from the oxygen-containing gas supply means 40 at a predetermined flow rate and supplied to the preheating unit 50-2 via the first flow path 50-1a of the heat exchanger 50-1. When the by-product gas G3 is supplied to the second flow path 50-1b, the oxygen-containing gas G1 flowing through the first flow path 50-1a is heated by the by-product gas G3 flowing through the second flow path 50-1b. To. Then, in the preheating section 50-2, the stainless steel tube 50-2a is heated, and the oxygen-containing gas G1 supplied to the stainless steel tube is heated to a predetermined temperature, for example, 600 ° C. Then, the oxygen-containing gas G1 heated to a predetermined temperature is supplied to the reducing gas generating means 30 via the gas introduction pipe 50a.

Next, the temperature inside the quartz tube 32a in the reducing gas generating means 30 is heated to 500 to 700 ° C., and the carbon source-containing material W contained in the quartz tube 32a and the air supplied to the quartz tube 32a are subjected to an oxidation reaction. To generate a reducing gas G2 (including a mixed gas composed of carbon monoxide and carbon dioxide). Then, the reducing gas G2 generated by the reducing gas generating means 30 is supplied to the reaction furnace 10 via the gas introduction pipe 30a. The reducing gas G2 supplied to the reaction furnace 10 is adjusted to contain a predetermined amount of oxygen as needed. The reducing gas G2 supplied to the reaction furnace 10 is introduced into the reaction tube 11 from the introduction port 14, and is supplied to the holding portion 13 in the reaction tube 11 through the through holes 11a-4. The flow rate of the reducing gas G2 supplied into the reaction tube 11 is, for example, 0.1 L / min to 1.0 L / min when the hole diameter of the through hole 11a-4 is 1.5 mm. When the through hole 11a-4 has a hole diameter larger than 1.5 mm, the flow rate of the reducing gas G2 can be set to a value larger than 1.0 L / min.

Next, as shown in FIG. 3, in the reaction furnace 10, for example, the inside of the reaction furnace 10 is heated at 400 ° C./h and held at 1100 to 1300 ° C. for 2 hours, and then the reduction supplied from the reducing gas generating means 30 is performed. The gas G2 is introduced into the inner pipe 11a through the through hole 11a-4, and the reducing gas G2 is ejected upward in the inner pipe 11a. As a result, in the inner pipe 11a, the mixture M in the vicinity of the penetration 11a-4 is blown upward by the reducing gas G2, and the mixture M at a position away from the through hole 11a-4 falls, and the mixture M rises and falls. By repeating the above steps, the fluidized bed portion 15 is formed directly above the holding portion 13. At this time, the length of the inner pipe 11a is preferably 30 cm or more in order to cope with the high flow rate of the reducing gas G2. Further, the inner diameter of the through hole 11a-4 is preferably, for example, 1 mm to 9 mm in consideration of the blowout amount of the reducing gas G2.

Then, the inside of the reaction tube 11 is heated to a predetermined temperature, and the first solid gallium compound in the mixture M and the reducing gas G2 are reacted in the inner tube 11a.
When the first solid gallium compound is solid gallium nitride and the reducing gas G2 contains a mixed gas composed of carbon monoxide and carbon dioxide (hereinafter referred to as "CO / CO ₂ mixed gas"), the fluid bed portion 15 is described below. The chemical formulas (1) and (2) of the above cause a reduction reaction and an oxidation reaction of gallium, and the collection part 16-1 has a fourth metal content higher than that of gallium in the first solid gallium compound. , The second solid gallium compound (gallium oxide), which is the second solid metal compound S1, is collected.
2GaN (solid) + CO ₂ (gas) → Ga ₂ O (gas) + N ₂ (gas) + CO (gas) ...
・ (1)
Ga ₂ O (gas) + O ₂ (gas) → Ga ₂ O ₃ (solid) ... (2)

In the reaction in which the first solid gallium compound is reduced to produce a gaseous gallium compound, as shown in the chemical formula (1), it is contained in the first solid gallium compound GaN and the reducing agent CO / CO ₂ mixed gas. Carbon dioxide reacts to produce the gaseous gallium compounds Ga ₂ O, nitrogen, and carbon monoxide.
Further, in the reaction in which the gaseous gallium compound is oxidized to produce the second solid gallium compound, as shown in the chemical formula (2), Ga ₂ O, which is a gaseous gallium compound, reacts with oxygen, which is an oxidizing agent, and the reaction occurs. Ga ₂ O ₃ which is a second solid gallium compound is produced.

When activated carbon (C) is added to the mixture M, the reaction between GaN (solid), activated carbon (C), and any of carbon dioxide (CO ₂ ) and oxygen (O ₂ ) proceeds in parallel with the above reaction. , Ga ₂ O, which is a gaseous gallium compound, is produced. However, since the probability that the solid activated carbon comes into contact with GaN is low, it is presumed that the reduction reaction of gallium that occurs in the inner tube 11a is mainly due to the CO / CO ₂ mixed gas.

When the first solid gallium compound is solid gallium nitride, in the step of obtaining the second solid gallium compound (solid gallium oxide) from the first solid gallium compound via the gaseous gallium compound, the mixture M of the first solid gallium compound is 1000 to 1000. It is preferable to heat in the range of 1300 ° C. Further, the temperature inside the reaction tube 11 and the oxygen partial pressure, particularly the temperature and the oxygen partial pressure of the collecting portion 16-1, are adjusted so that the vapor pressure of the gaseous gallium compound (Ga ₂ O) in the gallium mixture becomes the maximum value. Is preferable. That is, the reaction furnace 10 may further have an oxygen partial pressure control unit that controls the oxygen partial pressure in the reaction tube 11 in addition to the heating unit 12.

FIG. 4 is a graph illustrating the oxygen partial pressure dependence of the gallium vapor pressure concentrated by the noble metal concentrator of FIG. 1 at 1150 ° C. In the graph, the vapor pressure of Ga ₂ O (g) among the vapor pressures of gallium species reaches the maximum value at about 1 × 10 ⁴ Pa, and the oxygen partial pressure at this time is 1 × 10 ^-11 Pa (position a in the figure). ). Therefore, in this embodiment, the vapor pressure of Ga ₂ O (g) is used, and the oxygen partial pressure in the reaction tube 11 is set to 1 Pa (1 × 100) so that the vapor pressure of Ga ₂ ^O , which is a gaseous gallium compound, becomes large. Pa) It is preferable to control it to 1 × 10 ^-19 Pa or more, and 1 × 10 ^-7 Pa or less is more preferable. Further, at 1150 ° C., it is particularly preferable to adjust the oxygen partial pressure in the reaction tube ¹¹ to 1 × 10-11 Pa so that the vapor pressure of Ga ₂ O, which is a gaseous gallium compound, becomes the maximum value. The range of this oxygen partial pressure differs depending on the temperature, and is calculated by thermodynamic calculation using thermochemical data. Further, in this case, the reaction furnace 10 has an oxygen detection unit for measuring the oxygen partial pressure in the reaction tube 11, and a flow rate of the oxygen-containing gas G1 in the oxygen-containing gas supply means 40 based on the detection result of the oxygen detection unit. It may have a control unit for controlling the above. In this way, the oxygen partial pressure corresponding to the maximum value of the vapor pressure of Ga ₂ O (g) is set, and the oxygen in the reaction furnace 11 is set so that the oxygen partial pressure in the reaction tube 11 becomes the above oxygen partial pressure. By controlling the partial pressure or introducing the reducing gas G2 having the oxygen partial pressure into the reaction reactor 10, the collection unit 16-1 has a larger amount of Ga ₂ O (s), which is a second solid gallium compound. It becomes possible to collect.

The ratio of the mass of the gallium element in the first solid gallium compound to the mass of the mixture M containing the first solid gallium compound is the third metal content α3, and the ratio of the second solid gallium to the mass of the second solid gallium compound. When the ratio of the mass of the gallium element in the compound is the fourth metal content α4, the fourth metal content α4 is higher than the third metal content α3. Further, when the mass of gallium in the first solid gallium compound contained in the mixture M is m3 and the mass of gallium in the second solid gallium compound collected by the collecting unit 16-1 is m4, the yield γ1 (= M4 / m3 * 100) is 0.5% or more, preferably 10% or more. For example, 0.0012 g of Ga ₂ O ₃ (s) was collected from a mixture containing 0.10 g of GaN (s), and the yield γ1 achieved 1.1%.

Next, the by-product gas G3 generated by the reduction / oxidation reaction in the reaction tube 11 is discharged from the discharge port 17 through the through hole 11e-1 to the gas discharge pipe 60a. The by-product gas G3 includes, in addition to nitrogen and carbon monoxide produced by the reaction formula (1), Ga ₂ O ₃ (s), which is a second solid gallium compound produced by the reaction formula (2), and Contains carbon dioxide. The Ga ₂ O ₃ (s) -containing by-product gas G3 is supplied to the recovery means 80 via the gas discharge pipe 60a.

Then, in the recovery means 80 (FIG. 3), the by-product gas G3 spirally descends along the inner wall 81a of the separation portion 81, reaches the lower end 81b of the separation portion 81, and then passes through the center of the separation portion 81. It is discharged from the discharge port 81d provided at the upper end 81c of the separation portion. At this time, the Ga ₂ O ₃ (s) contained in the by-product gas G3 is centrifuged at the separation unit 81 and recovered as the second solid metal compound S2 at the recovery unit 82. Further, the by-product gas G3 discharged from the discharge port 81d of the recovery means 80 is supplied to the heat exchanger 50-1 via the gas discharge pipe 80a.

In the heat exchanger 50-1 (FIG. 1), the by-product gas G3 is introduced into the second flow path 50-1b, and the by-product gas G3 flowing through the second flow path 50-1b and the first flow path 50-1a The by-product gas G3 is cooled by exchanging heat energy with the oxygen-containing gas G1 flowing through the water. After that, the by-product gas G3 cooled by the heat exchanger 50-1 is supplied to the purification means 90, the by-product gas G3 is purified to obtain the purification gas G4, and the purification gas G4 is discharged to the outside.

As described above, in the method for concentrating a metal compound in (1-1) above, a mixture M containing a first solid gallium compound (solid gallium nitride) is heated to a predetermined temperature and a predetermined temperature using a reducing gas G2 containing carbon monoxide. By reducing under oxygen partial pressure, Ga ₂ O, which is a gaseous metal compound, is separated and oxidized to collect a second solid gallium compound (solid gallium oxide).

(1-2) When the first solid metal compound is the first solid gallium compound (solid gallium oxide) and the second solid metal compound is the second solid gallium compound (solid gallium oxide) Also in this case, the above (1-). Solid gallium oxide can be concentrated by the same method as in 1). In the fluidized bed section 15, gallium reduction reaction and oxidation reaction occur according to the following chemical formulas (3) and (4), and in the collection section 16-1, from the third metal content of gallium in the first solid gallium compound. The second solid gallium compound is collected with a high fourth metal content.
Ga ₂ O ₃ (solid) + 2CO (gas) → Ga ₂ O (gas) + 2CO ₂ (gas) ... (3)
Ga ₂ O (gas) + O ₂ (gas) → Ga ₂ O ₃ (solid) ... (4)

In the reaction in which the first solid gallium compound is reduced to produce a gaseous gallium compound, Ga ₂ O ₃ which is the first solid gallium compound and carbon monoxide which is a reducing agent react as shown in the chemical formula (3). As a result, Ga ₂ O, which is a gaseous gallium compound, and carbon dioxide are produced.
Further, in the reaction in which the gaseous gallium compound is reduced to produce solid gallium oxide which is the second solid gallium oxide, as shown in the chemical formula (4), Ga ₂ O which is the gaseous gallium compound reacts with oxygen. As a result, Ga ₂ O ₃ which is a second solid gallium compound is produced.

When the first solid gallium compound is the above-mentioned solid gallium oxide, in the step of obtaining the second solid gallium compound (solid gallium oxide) from the first solid gallium compound via the gaseous gallium compound, 900 a mixture of the first solid gallium compounds is used. It is preferable to heat the temperature above ° C. Further, it is preferable to adjust the temperature and oxygen partial pressure of the collecting unit 16-1 so that the vapor pressure of the gaseous gallium compound in the gallium mixture becomes the maximum value.

As described above, in the method for concentrating the metal compound in (1-2) above, the mixture containing the first solid gallium compound (solid gallium oxide) is mixed with the reducing gas G2 containing carbon monoxide at a predetermined temperature and a predetermined oxygen content. By reducing under pressure, Ga ₂ O, which is a gaseous metal compound, is separated and oxidized to collect a second solid gallium compound (solid gallium oxide).

(1-3) When the first solid metal compound is the first solid indium compound (solid indium oxide) and the second solid metal compound is the second solid indium compound (solid indium oxide) Also in this case, the above (1-). The solid indium oxide can be concentrated by the same method as in 1). In the fluidized bed portion 15, indium reduction reaction and oxidation reaction occur according to the following chemical formulas (5) and (6), and in the collection portion 16-1, from the third metal content of indium in the first solid indium compound. The second solid indium compound is collected with a high fourth metal content.
In ₂ O ₃ (solid) + 2CO (gas) → In ₂ O (gas) + 2CO ₂ (gas) ... (5)
In ₂ O (gas) + O ₂ (gas) → In ₂ O ₃ (solid) ... (6)

In the reaction in which the first solid indium compound is reduced to produce a gaseous gallium compound, as shown in the chemical formula (5), In ₂ O ₃ which is the first solid indium compound and carbon monoxide which is a reducing agent react. As a result, In ₂ O, which is a gaseous indium compound, and carbon dioxide are produced.
Further, in the reaction in which the gaseous indium compound is reduced to produce the solid indium oxide which is the second solid indium oxide, as shown in the chemical formula (6), the gaseous indium compound In ₂ O reacts with oxygen. As a result, In ₂ O ₃ which is a second solid indium compound is produced.

When the first solid indium compound is solid indium oxide, in the step of obtaining the second solid indium compound (solid gallium oxide) from the first solid indium compound via the gaseous indium compound, the mixture of the first solid indium compound is heated at 700 ° C. or higher. It is preferable to heat to. Further, it is preferable to adjust the temperature and oxygen partial pressure of the collecting unit 16-1 so that the vapor pressure of the gaseous indium compound in the indium mixture becomes the maximum value.

As described above, in the method for concentrating the metal compound in (1-3) above, the mixture containing the first solid indium compound (solid indium oxide) is mixed with the reducing gas G2 containing carbon monoxide at a predetermined temperature and a predetermined oxygen content. By reducing under pressure, In ₂ O, which is a gaseous metal compound, is separated and oxidized to collect a second solid indium compound (solid indium oxide).

(1-4) When the 1st solid metal compound is the 1st solid germanium compound (solid germanium oxide) and the 2nd solid metal compound is the 2nd solid germanium compound (solid germanium oxide) The solid germanium oxide can be concentrated by the same method as in 1). In the fluid bed portion 15, a reduction reaction and an oxidation reaction of germanium occur according to the following chemical formulas (7) and (8), and in the collection portion 16-1, from the third metal content of germanium in the first solid germanium compound. The second solid germanium compound is collected with a high fourth metal content.
GeO ₂ (solid) + CO (gas) → GeO (gas) + CO ₂ (gas) ... (7)
GeO (gas) + 1/2 * O ₂ (gas) → GeO ₂ (solid) ... (8)

In the reaction in which the first solid germanium compound is reduced to produce a gaseous germanium compound, as shown in the chemical formula (7), Ge ₂ O ₃ which is the first solid germanium compound and carbon monoxide which is a reducing agent react. As a result, Ge ₂ O, which is a gaseous germanium compound, and carbon dioxide are produced.
Further, in the reaction in which the gaseous germanium compound is reduced to produce solid germanium oxide which is a second solid germanium oxide, as shown in the chemical formula (8), Ge ₂ O which is a gaseous germanium compound reacts with oxygen. As a result, Ge ₂ O ₃ which is a second solid germanium compound is produced.

When the first solid germanium compound is solid germanium oxide, in the step of obtaining the second solid germanium compound (solid germanium oxide) from the first solid germanium compound via the gaseous germanium compound, the mixture of the first solid germanium compound is 700 ° C. or higher. It is preferable to heat to. Further, it is preferable to adjust the temperature and oxygen partial pressure of the collecting unit 16-1 so that the vapor pressure of the gaseous germanium compound in the germanium mixture becomes the maximum value.

As described above, in the method for concentrating the metal compound in (1-4) above, the mixture containing the first solid germanium compound (solid germanium oxide) is mixed with the reducing gas G2 containing carbon monoxide at a predetermined temperature and a predetermined oxygen content. By reducing under pressure, Ge ₂ O, which is a gaseous metal compound, is separated and oxidized to collect a second solid germanium compound (solid germanium oxide).

(1-5) When the first solid metal compound is the first solid tellurium compound (solid tellurium oxide) and the second solid metal compound is the second solid tellurium compound (solid tellurium oxide) Also in this case, the above (1-5). The solid tellurium oxide can be concentrated by the same method as in 1). In the fluidized bed portion 15, a reduction reaction and an oxidation reaction of tellurium occur according to the following chemical formulas (9) and (10), and in the collection portion 16-1, the content of the tertiary metal of tellurium in the first solid tellurium compound is higher than that of the tertiary metal content of tellurium. The second solid tellurium compound is collected with a high fourth metal content.
2TeO ₂ (solid) + 2CO (gas) → Te ₂ O ₂ (gas) + 2CO ₂ (gas) ... (9)
Te ₂ O ₂ (gas) + O ₂ (gas) → Te ₂ O ₃ (solid) ... (10)

In the reaction in which the first solid tellurium compound is reduced to produce a gaseous tellurium compound, as shown in the chemical formula (9), TeO ₂ which is the first solid tellurium compound and carbon monoxide which is a reducing agent react with each other. , The gaseous tellurium compound Te ₂ O ₂ , and carbon dioxide are produced.
Further, in the reaction in which the gaseous tellurium compound is reduced to produce the solid tellurium oxide which is the second solid tellurium oxide, as shown in the chemical formula (10), the gaseous tellurium compound Te ₂ O ₂ reacts with oxygen. Then, Te ₂ O ₃ which is a second solid tellurium compound is produced.

When the first solid tellurium compound is solid tellurium oxide, in the step of obtaining the second solid tellurium compound (solid tellurium oxide) from the first solid tellurium compound via the gaseous tellurium compound, the mixture of the first solid tellurium compound is heated to 200 ° C. or higher. It is preferable to heat to. Further, it is preferable to adjust the temperature and oxygen partial pressure of the collecting unit 16-1 so that the vapor pressure of the gaseous tellurium compound in the mixture becomes the maximum value.

As described above, in the method for concentrating the metal compound in (1-5) above, the mixture containing the first solid tellurium compound (solid tellurium oxide) is mixed with the reducing gas G2 containing carbon monoxide at a predetermined temperature and a predetermined oxygen content. By reducing under pressure, Te ₂ O ₂ which is a gaseous metal compound is separated and oxidized to collect a second solid tellurium compound (solid gallium oxide).

(1-6) When the first solid metal compound is the first solid cesium compound (solid cesium oxide) and the second solid metal compound is the second solid cesium compound (solid cesium oxide) In this case as well, the above (1-6) Solid cesium monoxide can be concentrated in the same manner as in 1). In the fluidized bed portion 15, a reduction reaction and an oxidation reaction of cesium occur according to the following chemical formulas (11) and (12), and in the collection portion 16-1, the content of the third metal of cesium in the first solid cesium compound is higher than that of the third metal content of cesium. The second solid cesium compound is collected with a high fourth metal content.
Cs ₂ O ₃ (solid) + 2CO (gas) → Cs ₂ O (gas) + 2CO ₂ (gas) ... (11)
Cs ₂ O (gas) + O ₂ (gas) → Cs ₂ O ₃ (solid) ... (12)

In the reaction in which the first solid cesium compound is reduced to produce a gaseous cesium compound, as shown in the chemical formula (11), Cs ₂ O ₃ which is the first solid cesium compound and carbon monoxide which is a reducing agent react. As a result, Cs ₂ O, which is a gaseous cesium compound, and carbon dioxide are produced.
Further, in the reaction in which the gaseous cesium compound is reduced to produce solid cesium oxide which is a second solid cesium oxide, as shown in the chemical formula (12), Cs ₂ O which is a gaseous cesium compound reacts with oxygen. As a result, Cs ₂ O ₃ , which is a second solid cesium compound, is produced.

When the first solid cesium compound is solid cesium oxide, in the step of obtaining the second solid cesium compound (solid cesium oxide) from the first solid cesium compound via the gaseous cesium compound, the mixture of the first solid cesium compound is brought to room temperature or higher. It is preferable to heat it. Further, it is preferable to adjust the temperature and oxygen partial pressure of the collecting unit 16-1 so that the vapor pressure of the gaseous cesium compound in the cesium mixture becomes the maximum value.

As described above, in the method for concentrating the metal compound in (1-6) above, the mixture containing the first solid cesium compound (solid cesium oxide) is mixed with the reducing gas G2 containing carbon monoxide at a predetermined temperature and a predetermined oxygen content. By reducing under pressure, Cs ₂ O, which is a gaseous metal compound, is separated and oxidized to collect a second solid cesium compound (solid cesium oxide).

<Relationship between various parameters in the reactor and yield γ1>
Next, the relationship between various parameters in the reactor and the yield γ1 of the second solid compound will be described with reference to FIGS. 5 to 10. In FIGS. 5 to 8, the case where the first solid compound is solid gallium nitride and the second solid compound is solid gallium oxide ((1-1) above) will be described as an example.

25 mg of gallium nitride (GaN) and 25 mg of aluminum oxide (Al ₂ O ₃ ) were charged into the holding portion of the above reactor, and as shown in FIG. 5, a collector composed of wound Pt wire was placed above the reactor. A Pt wire having a diameter of 0.3 mm was installed from above the reactor to the vicinity of the center position in the height direction of the reactor. Then, the temperature of the preheating furnace is 600 ° C., the temperature of the reducing gas generating means is 700 ° C., the temperature inside the reactor during the reduction / oxidation reaction of the reaction furnace (in this embodiment, the temperature of the ejection part) is 1125 ° C. to 1200 ° C., the preheating furnace. The flow rate of nitrogen gas (including impurity oxygen of 50 ppm or less) passing through the reducing gas generating means is set to 0.2 L / min to 0.25 L / min, and solid gallium oxide (Ga ₂ O ₃ ) collected by Pt wire is used. Was collected, and the yield γ1 was calculated by the above formula. At this time, the position of the collecting portion is changed within the range of 12.0 cm to 15.0 cm in height with reference to the upper end of the through hole of the reactor, and the solid gallium oxide collected at each height h is obtained. Yield γ1 was calculated. The nitrogen gas in the present invention is not a reducing gas but rather an oxidizing gas before being supplied to the concentrating device, and is changed to a reducing gas in the reducing gas generating means after being introduced into the concentrating device.

As a result, as shown in FIG. 6, the yield γ1 of solid gallium oxide in the GaN _{- Al2O3} system varies depending on the height of the collecting portion, and in particular, the height h is 12.5 cm to 13.4 cm. It can be seen that when the yield γ1 is 19% or more and the height h is 13.0 cm, the yield γ1 of the solid gallium oxide is 27%, which is the peak value. Therefore, in the GaN _- Al ₂ O3 system, it is presumed that the yield γ1 of solid gallium oxide can be improved by optimizing the height of the collecting portion.

Further, FIG. 7 shows the temperature distribution along the height direction in the reaction tube when the temperature inside the furnace (temperature at the ejection portion) is constant. As shown in FIG. 7, when the temperature of the ejection portion, that is, the upper end of the through hole is 1250 ° C., the temperature inside the pipe in the region having a height of 2 to 3 cm is slightly higher than the temperature of the ejection portion, but the height is 3 cm. The temperature inside the pipe in the region of more than 10 cm and 10 cm or less gradually decreases with height, and the temperature in the pipe in the region of 10 cm or more in height decreases almost linearly. Then, in FIG. 6, it can be seen that the temperature inside the tube at a height (h = 13.0 cm) of 27%, which is the peak value of the yield γ1, is about 850 ° C. Therefore, there is a correlation between the temperature distribution in the reaction tube and the height h, and it is presumed that the yield γ1 of solid gallium oxide can be improved by optimizing the temperature of the collecting portion.

Next, the same as in the case of FIG. 6 except that the temperature inside the reactor was kept constant at 1150 ° C. and the nitrogen gas flow rate was changed within the range of 0.18 L / min to 0.23 L / min, and each nitrogen was used. The yield γ1 of solid gallium oxide at the gas flow rate was calculated.
As a result, as shown in FIG. 8, the yield γ1 improves as the nitrogen gas flow rate increases, and the yield γ1 becomes 20% or more particularly when the nitrogen gas flow rate is 0.2 L / min or more. I understand. Since gallium nitride scatters when the nitrogen gas flow rate is 0.23 L / min or more, 0.23 L / min is the limit flow rate in this precious metal concentrator. Therefore, when the temperature inside the furnace (reaction temperature) is constant, the yield γ1 of solid gallium oxide can be improved by increasing the nitrogen gas flow rate in the range of the limit flow rate or less.

Next, the same as in the case of FIG. 6 except that the temperature inside the reactor was changed in the range of 1125 ° C to 1200 ° C and the nitrogen gas flow rate was 0.23 L / min, and solid oxidation at each furnace temperature was performed. The yield γ1 of gallium was calculated.
As a result, as shown in FIG. 9, the yield γ1 of the solid gallium oxide in the GaN _{- Al2O3} system varies depending on the temperature inside the reactor, and in particular, the temperature inside the reactor is 1125 ° C to 1200 ° C. Sometimes the yield γ1 is 20% or more, the yield γ1 is 35% or more when the furnace temperature is 1140 ° C to 1184 ° C, and the yield γ1 is the peak value when the furnace temperature is 1150 ° C. It turns out that it is 38%. The yield γ1 decreased when the temperature inside the furnace exceeded 1150 ° C. because the temperature near the collection site was higher than the precipitation temperature of solid gallium oxide and was outside the temperature range suitable for precipitation of solid gallium oxide. Inferred. Therefore, when the nitrogen gas flow rate is constant, it is presumed that the yield γ1 of solid gallium oxide can be improved by optimizing the temperature inside the furnace during the reduction / oxidation reaction.

Therefore, the relationship between the temperature of the collecting part and the yield γ1 of the solid gallium oxide when the temperature inside the furnace (the temperature of the ejection part) was constant was obtained. As a result, as shown in FIG. 10, when the temperature inside the furnace was kept constant at 1150 ° C., the yield of solid gallium oxide γ1 showed a peak value of 27% when the temperature of the collecting portion was around 850 ° C. It is presumed that the reason why the yield γ1 increases with the temperature rise in the range where the temperature of the collecting part is less than 850 ° C. is that a better air flow is formed in the vicinity of the collecting part with the temperature rise. Further, the reason why the yield γ1 decreases with the temperature rise in the range where the temperature of the collecting part exceeds 850 ° C. is because (1) the updraft generated in the vicinity of the collecting part increases with the temperature rise. The temperature near the collection part has not dropped to the proper temperature for precipitation of solid gallium oxide, and (2) the updraft generated near the collection part is disturbed by colliding with the lower surface of the spiral structure of the collection part. It is presumed that the solid gallium oxide deposited on the collection part is peeled off, scattered, etc., and the amount of precipitation decreases.

Therefore, it was confirmed that there is a correlation between the temperature of the collecting part, the temperature distribution in the furnace, and the yield γ1, and that the yield γ1 of the solid gallium oxide is improved by optimizing the temperature of the collecting part.

As described above, according to the present embodiment, the above-mentioned first in a mixture of first solid noble metals containing one or more kinds of noble metals selected from the group consisting of gold, silver and copper at a first metal content. 1 The solid noble metal is vaporized to be a gaseous noble metal, and then the gaseous noble metal is solidified to be a second solid noble metal, and the second solid noble metal is collected at a second metal content higher than the first metal content. The precious metal selected from the above group can be concentrated and collected, no waste liquid is generated during concentration, the environmental load is small, and complicated waste liquid treatment is not required. In addition, the metal can be concentrated with a simple device configuration that does not have a structure for waste liquid treatment, and a precious metal concentrating device 1 suitable for practical use can be provided.

FIG. 11 is a cross-sectional view showing a first modification of the reactor of FIG. Since the reactor of FIG. 11 is basically the same as the reactor of FIG. 2, overlapping description will be omitted, and different parts will be described below. The reactor 10 of FIG. 11 differs from the reactor 10 of FIG. 2 in that it has another collection unit in addition to the collection unit 16-1.
In the figure, the reaction furnace 10A includes a lid portion 21 arranged on the upper portion of the fluidized bed portion 15 and mounted on the upper portion of the inner pipe 11a. The lid portion 21 is a ceramic member having a mortar shape, and has a bottom portion 21a, a side wall portion 21b, and a through hole 21c provided in the bottom portion 21a. The lid portion 21 is made of a ceramic containing an oxide such as aluminum, magnesium, or zirconia as a main component.

The reactor 10A is located in the fluidized bed section 15 and has a collection section 16-2 for collecting the second solid metal compound. In this modification, the collecting portion 16-2 is a ceiling wall composed of the lid portion 21. Specifically, the collecting portion 16-2 is the lower surface 21d or the upper surface 21e of the bottom portion 21a of the lid portion 21. The collecting unit 16-2 collects the second solid noble metal obtained by solidifying the gaseous noble metal with a second metal content higher than that of the first metal content. Further, the second solid metal compounds S3 and S4 obtained by oxidizing the gaseous metal compound can be collected at a fourth metal content higher than that of the third metal content.

The fluidized bed portion 15 changes to a second solid noble metal due to the solidification of the gaseous noble metal, and the second solid noble metal adheres to the lower surface 21d of the bottom portion 21a by this solidification reaction. Further, as described above, the gas metal compound of the rare metal is changed to the second solid metal compound by the oxidation reaction, and the second solid metal compound S3 can be attached to the lower surface 21d of the bottom portion 21a by this oxidation reaction.

Further, the gaseous noble metal supplied from the fluidized bed portion 15 through the through hole 21c to the vicinity of the upper surface 21e of the bottom portion 21a changes to the second solid noble metal, and the second solid noble metal adheres to the upper surface 21e. At this time, the gaseous metal compound supplied from the fluidized floor portion 15 through the through hole 21c to the vicinity of the upper surface 21e of the bottom portion 21a changes to the second solid metal compound S4, and the second solid metal compound S4 adheres to the upper surface 21e. You can also do it. As a result, the second solid noble metal is collected by the collecting unit 16-2, and in addition, the second solid metal compounds S3 and S4 are collected.

The mass of gallium in the first solid gallium compound contained in the mixture M is m1, the mass of gallium in the second solid metal compound S1 collected by the collecting unit 16-1 is m2, and the mass of gallium in the collecting unit 16-2 is m2. When the total mass of gallium in the collected second solid metal compounds S3 and S4 is m3, the yield γ2 {= (m2 + m3) / m1 * 100} exceeds 1.0%, preferably 1. Over 5%. Therefore, by further providing the collecting portion 16-2 as a partition wall in the fluidized bed portion 15, it is possible to collect a larger amount of the second solid metal compound in both the collecting portions 16-1 and 16-2. Will be.

FIG. 12 is a cross-sectional view showing a second modification of the reactor of FIG. Since the reactor of FIG. 12 is basically the same as the reactor of FIG. 2, overlapping description will be omitted, and different parts will be described below. The reactor 10 of FIG. 12 differs from the reactor 10 of FIG. 2 in that it has another collection unit in addition to the collection unit 16-1.
In the figure, the reaction furnace 10B is located in the fluidized bed portion 15 and has a collecting portion 16-3 for collecting the second solid metal compound. In this modification, the collection unit 16-3 is a seed crystal material 22 held in the internal space of the reaction tube 11 and made of a second solid metal compound. The seed crystal material 22 is held in a state of being suspended in the fluidized bed portion 15 by the wire rod 23 attached to the closed portion 11e.

The collecting unit 16-3 can collect the second solid metal compound S5 obtained by oxidizing the gaseous metal compound with a second metal content higher than that of the first metal content. As described above, the fluidized bed portion 15 changes to a second solid noble metal due to the solidification of the gaseous noble metal, and the solidification reaction causes the inner peripheral surface (11a-2) of the tubular portion 11a-1 (see FIG. 2). A second solid noble metal adheres to the surface. At this time, as described above, the gas metal compound of the rare metal is changed to the second solid metal compound by the oxidation reaction, and the second solid metal compound S5 can be attached to the seed crystal material 22 by this oxidation reaction. As a result, the second solid metal compound S5 is collected by the collection unit 16-3.

The mass of gallium in the first solid gallium compound contained in the mixture M is m1, the mass of gallium in the second solid metal compound S1 collected by the collecting unit 16-1 is m2, and the mass of gallium in the collecting unit 16-3 is m2. When the mass of gallium in the collected second solid metal compound S5 is m4, the yield γ3 {= (m2 + m4) / m1 * 100} is 2.1% or more. Therefore, by further providing the collecting section 16-3 made of seed crystals in the fluidized bed section 15, more of the second solid metal compound can be collected by both the collecting sections 16-1 and 16-3. It will be possible.

<Other Embodiments of Precious Metal Concentrator>
FIG. 13 is a diagram schematically showing the configuration of the precious metal concentrator according to the second embodiment of the present invention.
The noble metal concentrator 1A of FIG. 13 is basically the same as the noble metal concentrator 1 of FIG. 1, and differs from the noble metal concentrator of FIG. 1 in that it does not have a preheating furnace 50-2. That is, the preheating furnace 50-2 of FIG. 1 heats the oxygen-containing gas G1 supplied from the heat exchanger 50-1 to a predetermined temperature, but the oxygen-containing gas G1 is heated to a predetermined temperature by the heat exchanger 50-1. If it is possible to heat, it is not necessary to provide a preheating furnace 50-2. Thereby, the device configuration can be further simplified, and a precious metal concentrator more suitable for practical use can be provided.

Further, the precious metal concentrator 1A may be further provided with a depressurizing means 91 which is provided in the gas discharging means 60 and depressurizes the inside of the reaction furnace 10. The depressurizing means 91 is, for example, a fan attached to the gas discharge pipe 60a, and is arranged downstream of the reactor 10 and upstream of the recovery means 80. When the by-product gas G3 has a high temperature, a cooling means for cooling the by-product gas G3 may be provided downstream of the reactor 10 and upstream of the decompression means 91. As a result, the pressure inside the reaction tube 11 becomes lower than the normal pressure inside the tube, and the reduction reaction of the rare metal in the fluidized bed portion 15 can be performed at a temperature lower than the normal time, and energy saving can be achieved.

FIG. 14 is a diagram schematically showing the configuration of the precious metal concentrator according to the third embodiment of the present invention. The noble metal concentrator of FIG. 14 is basically the same as the noble metal concentrator 1 of FIG. 1, does not have a preheating furnace 50-2, and uses another reducing gas generating means instead of the reducing gas generating means 30. It differs from the precious metal concentrator of FIG. 1 in that it is provided.

The noble metal concentrator 1B of FIG. 14 includes a reducing gas generating means 92 that generates a reducing gas G2'that reduces a first solid metal compound containing a rare metal and supplies it to the reaction furnace 10. The reducing gas generating means 92 is, for example, a rotary kiln, and is connected to a rotatably provided furnace body 92a and a heat exchanger 50-1, and an oxygen-containing gas G1 from the heat exchanger is transferred to the furnace body 92a. The gas supply unit 92b for supplying, the material supply unit 92c for supplying the carbon source-containing material W to the furnace body 92a, the burner 92d attached to the furnace body 92a, and the reduction generated in the furnace body 92a. It includes a gas discharge unit 92e for supplying the gas G2'to the gas introduction pipe 30a, and a carbonized solid material discharge unit 92f for discharging the carbonized solid material produced as a by-product during the generation of the reduced gas.

The reducing gas generating means 92 heats the oxygen-containing gas G1 supplied from the preheating unit 50-2 and the carbon source-containing material W supplied from the material supply unit 92c with a burner 92d, and carbon monoxide is generated by an oxidation reaction of carbon. The reduced gas G2'containing the above gas is generated and supplied to the reaction furnace 10 via the gas introduction pipe 30a. As described above, according to the configuration of the reducing gas generating means 92, it is possible to continuously supply the carbon source-containing material W, generate the reducing gas G2', and discharge the carbonized solid substance, which is more practical. A precious metal concentrator can be provided.

FIG. 15 is a diagram illustrating a rare metal recycling model realized by using the precious metal concentrator 1 of FIG.
Conventionally, in the manufacturing process of electric / electronic equipment using gold, which is a precious metal, LED device P2 is first manufactured at a device manufacturing factory 131 using gold P1 mined from ore or the like, and then an equipment manufacturer. At 132, an electric / electronic device P3 such as an LED bulb on which the LED device P2 is mounted is manufactured. Then, the electric / electronic device P3 is used as lighting in the consumer's building 133 and the like.

Until now, a recycling model for used electrical and electronic equipment equipped with LED devices has not been specifically studied. In addition, the manufacture and sale of consumer electric and electronic devices equipped with LED devices started around 2011, and the design life of general LED devices is as long as about 10 years, so the manufacture and sale of these devices After 10 years have passed from the start, it is expected that a large amount of electric / electronic devices whose design life has expired will be left over, and there is a demand for the early realization of a recycling model of electric / electronic devices equipped with LED devices.

Therefore, in the recycling model proposed by the present invention, the noble metal concentrator 1 according to the above embodiment is introduced into the recovery factory 134, and the used electric / electronic equipment used in the consumer's building 133 at the recovery factory 134. P4 is recovered and used electric / electronic equipment P4 is disassembled to obtain a used LED device. Then, using the precious metal concentrator 1, the used LED device is supplied to the noble metal concentrator 1 as a mixture M, and the gold (or gold, gallium nitride, etc.) contained in the mixture M is concentrated by a dry method and solidified. The precious metal-containing mixture P5 containing gold, which is a precious metal, is recovered. Further, the waste resin obtained by decomposing the used electric / electronic device P4 is supplied to the reducing gas generating means 30 as the carbon source-containing material W to generate the reducing gas G2.

As a result, a large amount of used electric / electronic equipment P4 can be processed, and the precious metal-containing mixture P5 in which the precious metal is concentrated can be recovered. Therefore, by supplying the noble metal-containing mixture P5 or the gallium recovered from the mixture from the recovery factory 134 to the element manufacturing factory 131, the gallium contained in the used electric / electronic device P4 is efficiently recycled at the element manufacturing factory 131. This makes it possible to realize a recycling model of used electric / electronic equipment P4 at an early stage.

Although the precious metal concentrator according to the above embodiment has been described above, the present invention is not limited to the described embodiment, and various modifications and modifications can be made based on the technical idea of the present invention.

For example, the reactor can be a reactor having the functions of the present invention based on various high-temperature furnaces known as heat treatment systems. Examples of the waste heat treatment system include a stoker furnace, a fluidized bed furnace, a rotary kiln, a submersible combustion furnace, a melting furnace, a gasification combustion furnace, a gasification reforming furnace, an oilification facility, and a dry distillation furnace (carbonization furnace). (Source: Central Environment Council Waste and Recycling Association, Waste Disposal Standards Expert Committee (6th) As soon as proceedings, excerpted from materials). Examples of the target waste include sludge, waste plastics, paper waste, wood waste, fiber waste, animal and plant residues, waste oil, waste solvent, incineration residue, inorganic substances, etc., and the heat treatment system is used for the treatment of these wastes. It has been optimized. Therefore, the reaction furnace of the present invention can be configured by optimizing the heat treatment system as described above so as to have the above-mentioned essential functions of the present invention. When the present invention is implemented as an industry, unnecessary configurations can be omitted and simplified, and the device scale and processing capacity can be increased or decreased according to the application or specifications.

Further, the precious metal concentrator of the present invention is suitable for implementation on a relatively small scale, and is particularly useful as a research device or a small unit for verification. Further, such a small unit can be used as a so-called "desktop recycling factory" used in educational institutions, research institutes, and the like.

Hereinafter, examples of the present invention will be described. The present invention is not limited to the examples shown below.
Using a precious metal concentrator as shown in FIG. 5, a quartz plate was hung at the tip of the Pt wire instead of the Pt wire having a winding portion, and 1.5 g of the LED device as a mixture was put into the reaction furnace. Next, nitrogen gas (impurity oxygen of 50 ppm or less) was supplied at a flow rate of 0.2 L / min. Then, in the heating part of the reactor, an infrared gold image furnace (manufactured by Advance Riko Co., Ltd., device name "RHL-E410P", temperature range (specification): room temperature to 1400 ° C), heat treatment zone (specification): φ10 mm x 80 mm ) Was set in the reactor at a set temperature of 1150 ° C. and a heating time of 5 hours. did.
Of the inner peripheral surface of the inner tube, the position where the temperature is 1000 ° C. or higher is suitable for collecting the precipitate, so that position was set as the collecting position.

When the precipitate adhering to the sampling position was analyzed by SEM-EDX (manufactured by Hitachi High Technology Co., Ltd., device name "SU8020"), 48.9% by mass of the detected substance was Cu element and 23.6% by mass was O. Since 18.1% by mass was Si element, 8.6% by mass was Ag element, 0.4% by mass was Au element, and 0.3% by mass was Al element, a large amount of Au was found in the detected material. It was found that Ag and Cu were present.

Therefore, the recovery part of the inner tube including the above collection position is cut, the recovery part is divided into four equal parts, the mass of the precipitate deposited on each tube piece is analyzed, and the Au collected from the four tube pieces is analyzed. The total mass and yield were determined. The ICP mass spectrometry method was used for mass spectrometry (manufactured by Agilent Technologies, Ltd., device name "Agilent 7700 series"), and the total mass and yield of Ag and Cu were determined by the same method as above. .. Au and Ag were treated with aqua regia, and Cu was treated with nitric acid. Further, the same experiment as above was performed three times, and the average value of each value for each of the three experiments was calculated for each element of Au, Ag, and Cu. The results are shown in Table 1.

As shown in Table 1, the maximum yield of Au was 1.3% and the average yield was 0.88%, indicating that Au can be concentrated and recovered in a high yield. Further, the maximum yield of Ag was 19.1% and the average yield was 8.6%, indicating that Ag can be concentrated and recovered at a very high yield. Further, the maximum yield of Cu was 9.5% and the average yield was 8.1%, indicating that Cu can be concentrated and recovered at a very high yield.

Since gold, which is a precious metal, is an important element applied to CIGS type thin film solar panels and light emitting diodes (LEDs), this technology separates gold from ores mined from mines and used electronic components. It is available for. In particular, this technology is very useful because it can meet the needs of recycling gold from waste LEDs by the drywall method.

1 Noble metal concentrator 1A Noble metal concentrator 1B Noble metal concentrator 10 Reaction furnace 10A Reaction furnace 10B Reaction furnace 11 Reaction tube 11a Inner tube 11a-1 Tubular part 11a-2 Inner peripheral surface 11a-3 Bottom 11a-4 Through hole 11d-1 Through hole 11e-1 Through hole 11b Support pipe 11c Outer pipe 11d Closure part 11e Closure part 11f Supply part 11g Lid part 12 Heating part 12a Furnace body 12b Heater 13 Holding part 14 Introductory part 15 Flowing floor part 16-1 Collection part 16 -2 Collection section 16-3 Collection section 17 Discharge port 21 Cover section 21a Bottom section 21b Side wall section 21c Through hole 21d Bottom surface 21e Top surface 22 Species crystal material 30 Reduced gas generation means 30a Gas introduction pipe 31 Material supply section 32 Generation section 32a Quartz tube 32b heater
40 Oxygen-containing gas supply means 50 Gas heating means 50a Gas introduction pipe 50-1 Heat exchanger 50-1a First flow path 50-1b Second flow path 50-2 Preheating part 50-2a Stainless steel pipe 50-2b Heating part 60 Gas discharge means 60a Gas discharge pipe 80 Recovery means 81 Separation part 81a Inner wall 81b Lower end 81c Upper end 81d Discharge port 82 Recovery part 90 Purification means 91 Decompression means 92 Reduction gas generation means 92a Furnace 92b Gas supply part 92c Material supply part 92d Burner 92e Gas discharge section 92f Carbonized solids discharge section 100 Reaction furnace 101 Reaction tube 101a Inner tube 101b Support stand 101c Outer tube 101d Supply section 102 Heating section 103 Holding section 104 Introduction tube 105 Flow bed section 107 Discharge port 108 Reaction tube temperature control section 110 Reducing gas supply means 111 Stainless steel tube 112 Heating unit 113 Reducing gas temperature control unit 114 Oxygen partial pressure control unit 131 Element manufacturing plant 132 Equipment manufacturer 133 Building 134 Recovery plant G1 Oxygen-containing gas G2 Reducing gas G2'Reducing gas G2 "Reducing gas G3 By-product gas G4 Purification gas L Flow path M Mixture P1 Gallium P2 LED device P3 Electric / electronic equipment P4 Used electric / electronic equipment P5 Noble metal-containing mixture S1 Second solid metal compound S2 Second solid metal compound S3 Second solid metal Compound S4 Second solid metal compound S5 Second solid metal compound W Carbon source-containing material

Claims (5)

A step of vaporizing the first solid noble metal in a mixture of first solid noble metals containing one or more noble metals selected from the group consisting of gold, silver and copper at a first metal content to obtain a gaseous noble metal. When,
A step of solidifying the gaseous noble metal and collecting the second solid noble metal as a second solid noble metal with a second metal content higher than that of the first metal content.
Have,
The mixture comprises a first solid metal compound containing a metal selected from the group consisting of gallium, indium, germanium, tellurium, and cesium at a third metal content.
The step of vaporizing the first solid noble metal to obtain the gaseous noble metal is carried out together with the step of reducing the first solid metal compound in the mixture to form a gaseous metal compound.
In the step of collecting the second solid noble metal at the second metal content, the gas metal compound is oxidized to obtain the second solid metal compound as the second solid metal compound, and the second solid metal compound is higher than the third metal content. A method for concentrating precious metals , which is performed together with the process of collecting by metal content . The precious metal concentration method according to claim 1 , wherein the mixture comprises used electronic devices. The first solid noble metal in the mixture of the first solid noble metal containing one or more kinds of noble metals selected from the group consisting of gold, silver and copper at the first metal content is vaporized into a gaseous noble metal. A reaction furnace is provided which solidifies the gaseous noble metal and collects the second solid noble metal as a second solid noble metal at a second metal content higher than that of the first metal content .
The reactor is
A reaction tube for reacting the first solid noble metal in the internal space,
A heating unit that heats the reaction tube and
A holding portion provided in the lower part of the reaction tube and holding the first solid noble metal, and a holding portion.
An introduction port provided in the lower part of the holding part and for introducing the introduction gas from the lower part of the reaction tube into the holding part.
A fluidized bed portion provided above the holding portion and allowing the first solid noble metal to flow by the pressure of introducing the introduced gas into the holding portion.
A collecting section located above the fluidized bed and collecting the second solid noble metal, and a collecting section.
A precious metal concentrator provided above the collection unit and having a discharge port for discharging by-product gas generated in the reaction furnace from the inside of the reaction tube to the outside . The noble metal concentrator according to claim 3 , wherein the collecting portion is a part of a side wall defining an internal space of the reaction tube. The precious metal concentrator according to claim 3 or 4 , wherein the mixture comprises used electrical and electronic equipment.

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