JP5016895B2 - Indium recovery method and apparatus - Google Patents

Description

  The present invention relates to a method and apparatus for recovering indium, and more particularly, to a method and apparatus for recovering indium as a valuable metal element or alloy from a liquid to be treated such as a waste liquid containing In (indium).

  In general, industrial waste liquids may contain various metals, and attempts have been made to collect them as valuable metals as simple substances. For example, plating factory waste liquid contains Ni, Cu, Zn, etc., semiconductor manufacturing factory waste liquid contains Cu, Ga, etc., and liquid crystal manufacturing factory waste liquid contains In etc. If these can be recovered, it becomes possible to reuse those metals.

  In particular, In is a rare metal, and in recent years, various studies have been made on its recovery technology. Generally, as a waste liquid treatment technology for recovering heavy metals, agglomeration precipitation treatment, coprecipitation treatment using chemicals, etc. are generally adopted. When the concentration is low, metals are also removed using an adsorbent. It is. These techniques are also used as an In recovery technique. For example, there are techniques described in Patent Document 1 and Patent Document 2 below.

JP 2006-28608 A JP 2005-314786 A

  Patent Document 1 relates to a method for separating In and Sn from scrap, and is a technique for separating In by producing In and Sn hydroxides by coprecipitation treatment, which is widely used for the separation of In and Sn. Technology. Patent Document 2 relates to a method for recovering indium, which is a technique for recovering indium by precipitating an indium salt using oxalic acid as a precipitant.

  However, in the coprecipitation treatment as described above, indium forms a hydroxide precipitate, and this indium precipitate forms a slurry, but this slurry has poor sedimentation and dehydration properties, and the water content is also low. Since it is high, there is a problem that the volume increases. For this reason, there is a problem that the transportation cost of the slurry becomes high and the economy is poor. In addition, even if the slurry is dried to lower the water content and the volume is reduced, fine powder of indium hydroxide is generated and handling may be worsened. There was also a problem that the cost was low and the processing cost was high.

  Therefore, the present inventors utilize a so-called cementation method in which the recovery target metal contained in the liquid to be treated is deposited and recovered by using the difference in the ionization tendency of the metal. We have intensively studied the technology for recovering In. As a technique of the cementation method, for example, in the metal recovery from the waste plating solution, there is a method in which iron scrap is put into the waste plating solution and the recovery target metal such as Cu is recovered. In addition, improvements were made to the general cementation technique, and attempts were made to actually recover In from various industrial waste liquids.

  However, a new problem was encountered in the process of attempting to recover In using such a cementation technique. That is, when nitrate ions or oxalate ions are contained in the waste liquid, a cementation reaction does not occur suitably, and there is a problem that In is not deposited on the deposition metal. Originally, the cementation reaction should theoretically be preferred if the metal for precipitation is selected by focusing on the difference in ionization tendency between the metal to be recovered and the metal for precipitation, but it contains nitrate ions and oxalate ions. As for the waste liquid that was not deposited, it was found that In could not be precipitated due to the presence of nitrate ions or oxalate ions even though In could be deposited using the same kind of deposition metal.

  Industrial waste liquids containing nitrate ions and oxalate ions together with In exist in reality, for example, cleaning waste liquids for target materials and etching waste liquids for flat panel displays (FPD), and thus newly generated as described above. The problem is a problem that must be solved when recovering In from this type of waste liquid.

  The present invention has been made in order to solve such problems. In particular, the above-mentioned cementation reaction technology has been developed from a liquid to be treated such as a waste liquid containing nitrate ions and oxalate ions together with In. It is an object of the present invention to provide a recovery method and apparatus that can suitably recover In as a single metal or alloy that is a valuable material.

  In order to solve such problems, the present invention has been made as a method and apparatus for recovering indium. The invention according to claim 1 according to the method for recovering indium contains indium in an ionic state. , A method of recovering indium from a liquid to be treated containing at least one of nitrate ions and oxalate ions, wherein a metal for precipitation having a higher ionization tendency than indium and a chlorine ion source are treated liquid Indium is recovered by precipitating indium contained in the liquid to be treated on the surface of the deposition metal due to a difference in ionization tendency. Here, the chlorine ion source is such that chloride ions are generated in the liquid to be treated, such as chloride and hydrochloric acid.

  The invention according to claim 2 is a method for recovering indium from a liquid to be treated which contains indium in an ionic state and at least one of nitrate ion or oxalate ion. The liquid to be processed flows into the adjustment tank 12 and chlorine ions are added to the adjustment tank 12, and then the liquid to be processed in the adjustment tank 12 flows into the reactor main body and indium in the reactor main body. A metal for precipitation having a higher ionization tendency than that, and collecting indium by depositing indium contained in the liquid to be treated on the surface of the metal for precipitation due to a difference in ionization tendency. . Furthermore, the invention of claim 3 is characterized in that in the indium recovery method of claim 1 or 2, indium deposited on the surface of the depositing metal is peeled off and collected from the depositing metal.

  Further, the invention according to claim 4 is the method for recovering indium according to any one of claims 1 to 3, wherein the processing liquid after recovering indium from the depositing metal is added to the liquid to be processed which is a stock solution. The processing is performed again.

  Further, the invention according to claim 5 according to the indium recovery apparatus is prepared by adding indium in an ion state and at least one of nitrate ion or oxalate ion and adding a chlorine ion source. Metal deposition for flowing in the liquid to be treated and adding a deposition metal having a larger ionization tendency than indium to deposit indium contained in the liquid to be treated on the surface of the deposition metal due to a difference in ionization tendency A reactor main body for performing the reaction is provided.

  Furthermore, the invention according to claim 6 accommodates a liquid to be treated which contains indium in an ionic state and at least one of nitrate ion or oxalate ion, and is adjusted by adding a chlorine ion source. In addition to the adjustment tank 12 and the treatment liquid in the adjustment tank 12 flowing in, a precipitation metal having a higher ionization tendency than indium is added, and the indium contained in the treatment liquid due to the difference in ionization tendency A reactor main body for performing a metal deposition reaction for depositing on the surface of the metal for deposition is provided. Furthermore, the invention according to claim 8 is characterized by further comprising a peeling means for peeling indium deposited on the surface of the depositing metal from the depositing metal.

Furthermore, the invention according to claim 7 is the indium recovery device according to claim 7 or 8,
A return flow path is provided in which the treatment liquid after recovering indium from the depositing metal is added to the liquid to be treated, which is a stock solution, and the treatment is performed again.

  In the present invention, as described above, a deposition metal having a higher ionization tendency than indium and a chlorine ion source are contained in the liquid to be treated containing indium in an ionic state and at least one of nitrate ion or oxalate ion. Since the indium contained in the liquid to be treated is deposited on the surface of the deposition metal due to the difference in ionization tendency and collected by the difference in ionization tendency, nitrate ions and Despite the presence of acid ions, the presence of the chlorine ion source made it possible to suitably deposit indium on the deposition metal. Further, indium can be recovered more easily by peeling indium from the deposition metal by a peeling means.

  When nitrate ions and oxalate ions are present in the liquid to be treated as described above, a chlorine ion source is added to the liquid to be treated even though In cannot be deposited on the deposition metal. The reason why the precipitation of selenium is possible is considered as follows. That is, it is recognized that the presence of nitrate ions and oxalate ions in a certain concentration changes the form in the solution, thereby lowering the standard reduction potential of In from a value normally considered. Thus, the standard reduction potential of Al and Zn constituting the deposition metal also increases, and the potential difference between the recovered metal In and the deposition metals Al, Zn, etc. becomes smaller, making it difficult to reduce the In precipitation. It is thought that. Therefore, when chloride or hydrochloric acid is added as a chloride ion source such as sodium chloride or potassium chloride, In forms a chloro complex, and the standard reduction potential, which has been lowered by nitrate ions and oxalate ions, rises again. It seems that In can be reduced and deposited on the metal for precipitation.

  Another reason is that the potential of In changes due to the presence of nitrate ions or oxalate ions in the liquid to be treated, and becomes a region in the stable potential-pH diagram as In ions, which is a metal for precipitation. The reduction reaction due to Al is less likely to occur, but the addition of Cl ions changes to a region in the potential-pH diagram which is stable as In metal, and the reduction reaction due to Al as a deposition metal is likely to occur. Is also possible.

Furthermore, nitrate ions in the solution react with Al and Zn constituting the deposition metal to form nitrogen dioxide and nitric oxide and are released as gases, and oxalate ions in the solution constitute the deposition metal. It reacts with Al and Zn to form nitrogen dioxide and nitric oxide and is released as a gas.
In addition, when the treatment liquid after separating and recovering indium from the deposition metal is added to the liquid to be treated which is the stock solution and the treatment is performed again, chloride ions remain in the treatment liquid after the collection. As a result, the residual chlorine ions are reused. As a result, the amount of the chlorine ion source to be added can be reduced, and the processing cost can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
As shown in FIG. 1, the indium recovery apparatus of the present embodiment includes a reactor main body 1, an adjustment tank 12, and a filter 13. The reactor main body 1 is for depositing In from the waste liquid by a cementation reaction (metal precipitation reaction) as will be described later. Prior to that, the adjustment tank 12 adds a chlorine ion (Cl ⁻ ) source to the waste liquid. The filter 13 is for separating and recovering In deposited in the reactor main body 1. The separated processing liquid is configured to be able to be returned to the adjustment tank 12, and a flow path for that purpose is provided between the filter 13 and the adjustment tank 12. A flow path from the adjustment tank 12 to the reactor main body 1 and a flow path from the reactor main body 1 to the filter 13 are also provided. In FIG. 1, a pump for circulating the liquid to be treated is not shown.
This embodiment demonstrates the case where waste liquid is made into object as a to-be-processed liquid. The reactor body 1 is vertically long as shown in FIG. 2, and includes a reactor upper part 2, a reactor intermediate part 3, and a reactor lower part 4, which are continuously connected via connecting parts 5 and 6, respectively. The reactor upper part 2, the reactor intermediate part 3, and the reactor lower part 4 are formed to have the same width, but the cross-sectional area of the reactor upper part 2 is formed larger than the cross-sectional area of the reactor intermediate part 3, and the reactor intermediate part 3 is cut off. The area is larger than the cross-sectional area of the reactor lower part 4. As a result, as a whole, the cross-sectional area of the reactor body 1 is configured to discontinuously increase upward. The continuous portions 5 and 6 are formed in a taper shape that is wide upward.

  Under the reactor lower part 4, a substantially conical inflow chamber 7 for inflowing the waste liquid to be treated is provided, and an inflow pipe 8 is provided in the lower part thereof. Although not shown, the inflow pipe 8 is provided with a check valve. Further, an upper chamber 9 is provided on the upper side of the reactor upper part 2, and a discharge pipe 10 for discharging the recovered flake-like or particulate recovery target metal is provided on the side part. The upper chamber 9 is a part for discharging the metal recovered by such a discharge pipe 10 and for causing a so-called cementation reaction (metal precipitation reaction) based on the difference in ionization tendency from the metal to be recovered. This is also a portion into which metal particles of a deposition metal having a larger ionization tendency than the metal to be collected are introduced. Actually, the cementation reaction between the input metal and the recovered metal occurs in the entire reactor body 1.

  And while the waste liquid which flowed in from the inflow pipe 8 reaches the discharge pipe 10, it is comprised so that the fluid bed may form the fluidized bed by a metal particle, rising that vertical direction. Furthermore, ultrasonic oscillators 11a, 11b, and 11c serving as peeling means for peeling the metal to be collected, which is a metal contained in the waste liquid and deposited on the charged metal particles by the cementation reaction, are reactors. It is provided in the upper part 2, the reactor intermediate part 3, and the reactor lower part 4, respectively.

In this embodiment, zinc (Zn) or aluminum (Al) particles are used as the metal particles to be input. The target waste liquid includes, for example, an aluminum target cleaning waste liquid containing In ions and nitrate ions (NO ₃ ⁻ ) and oxalate ions (C ₂ O ₄ ²⁻ ), or nitric acid or oxalic acid. Etching waste liquid of FPD using the like is used. Metal particles having an average particle diameter of 2 mm are used in the present embodiment, although metal particles having an average particle diameter of 0.1 to 8 mm can be used. The average particle diameter is measured by an image analysis method or a JIS Z 8801 sieving test method.

Then, a method for recovering indium by the indium recovery device having such a configuration will be described. First, waste liquid to be treated is supplied to the adjustment tank 12, and the adjustment tank 12 is a source of chlorine ions (Cl ⁻ ). Add chlorides such as sodium chloride and potassium chloride. Since indium forms a hydroxide precipitate when the pH increases, the pH is adjusted to 1.5 or less in advance so as not to form a precipitate. Further, if the pH is too low, the reaction with the deposition metal used is promoted, and H ₂ , NO, NO ₂ gas is generated and the deposition metal is consumed wastefully, so the pH is preferably 0.5 or more. .
In addition, when pH is higher than the said range, it is preferable to adjust pH by hydrochloric acid, and when pH is lower than the said range, it is preferable to adjust pH by adding alkalis, such as NaOH.

  Next, the liquid to be treated which has been adjusted by adding chloride in this manner flows from the inflow pipe 8 into the reactor body 1 through the inflow chamber 7. On the other hand, metal particles (Zn or Al particles) for causing a cementation reaction are introduced from the upper chamber 9. In the reactor main body 1, the inflowing waste liquid rises in the vertical direction, while the metal particles introduced from the upper chamber 9 are in a fluidized state so as to form a fluidized bed.

  Then, a so-called cementation reaction is caused based on a difference in ionization tendency between In contained in the waste liquid and Zn or Al as the charged metal particles. This will be described in more detail. The reduction reaction of each metal ion is as shown in the following formulas (1) to (3), and the standard electrode potential (E °) of each metal ion is shown respectively.

In ³⁺ + 3e → In (1) -0.34V
Zn ²⁺ + 2e → Zn (2) −0.76V
Al ³⁺ + 3e → Al (3) -1.66V

As is clear from the above (1) to (3), the standard reduction potential of Zn ²⁺ and Al ³⁺ is smaller than that of In ³⁺ . In other words, the ionization tendency of Zn and Al is larger than that of In. Therefore, Zn or Al having a large ionization tendency becomes Zn ²⁺ or Al ^{3+ in the} fluidized state as described above and is eluted into the waste liquid, and together with the In ³⁺ contained in the waste liquid. Becomes In and precipitates on the surface of Zn or Al particles.

In this case, since the waste liquid contains nitrate ion (NO ₃ ⁻ ) or oxalate ion (C ₂ O ₄ ²⁻ ), the standard reduction potential of In may be lowered, and Al or There is a possibility that the standard reduction potential of Zn increases, and the potential difference between In and Al or Zn becomes small, and there is a possibility that the reduction precipitation of In becomes difficult. However, in this embodiment, since the liquid to be processed is supplied to the adjustment tank 12 in advance and a chlorine ion (Cl ⁻ ) source is added, when the liquid to be processed flows into the reactor main body 1, chlorine is added. The ion (Cl ⁻ ) forms a chloro complex of In, thereby increasing the standard reduction potential of In again, and as a result, it does not prevent In from precipitating on the surface of Zn or Al particles. It is.

  And after precipitating In on the surface of Zn or Al particle | grains by such a cementation reaction, the ultrasonic oscillators 11a, 11b, and 11c are operated. By operating the ultrasonic oscillators 11a, 11b, and 11c, ultrasonic waves oscillated from the ultrasonic oscillators 11a, 11b, and 11c are vibrated and stirred by the Zn particles or Al particles in which the In is precipitated. Thus, the deposited In is forcibly separated from the Zn particles or Al particles. In this case, the ultrasonic oscillators 11a, 11b, and 11c can be operated continuously. However, if the ultrasonic oscillators are operated continuously, the ultrasonic oscillator generates heat, and the ultrasonic oscillator is operated for a long time. May become difficult. Further, when the ultrasonic oscillator is continuously operated, the deposited metal (In) is peeled off sequentially before growing to a certain size, and as a result, a certain size of metal (In) is obtained. There is a risk of not. In this regard, when the ultrasonic oscillator is operated intermittently, there is little risk of inadvertent peeling until the deposited metal becomes large to some extent, so that the separated metal can be easily separated. Therefore, it is preferable to operate the ultrasonic oscillators 11a, 11b, and 11c intermittently. The intermittent operation in this case is performed, for example, by turning on for 2 seconds, turning off for 8 seconds, or the like.

  The treatment liquid containing In thus peeled is discharged from the upper chamber 9 through the discharge pipe 10 to the outside of the reactor main body 1, separated by the filter 13, and the separated In is recovered. is there. On the other hand, the separated treatment liquid is returned to the adjustment tank 12. In this case, in the present embodiment, since the particulate metal is used as the deposition metal to be deposited for depositing the metal to be recovered, for example, cement is compared with the case where zinc scrap is introduced. The surface area of the metal (Zn) for causing the titration reaction is increased, and the speed of the In precipitation reaction is improved.

  And after the deposition of the metal that has grown to some extent is recognized, the forced detachment by the ultrasonic vibration as described above can always expose the new metal surface (Zn particle surface) and maintain the reaction rate. it can. Further, compared to the conventional method of throwing in zinc scrap, impurities other than In are very small in the separated recovered metal.

Further, since the metal particles made of Zn flow in the reactor main body 1 and Zn ²⁺ is eluted by the above cementation reaction, the particle size at the initial charging time of the metal particles charged into the upper chamber 9 is It will inevitably decrease over time. As a result, since the waste liquid ascends in the reactor main body 1 at substantially the same upward flow rate, the metal particles whose particle size decreases and decreases toward the upper part are inadvertently overflowed from the reactor main body 1. There is a risk of flowing.

  However, in this embodiment, since the cross-sectional area of the reactor body 1 is formed so as to increase discontinuously as it goes upward, the upward flow velocity of the waste liquid in the reactor body 1 gradually decreases. Therefore, the metal particles whose particle size is reduced by the cementation reaction or the like as described above are held in the reactor body 1 without inadvertently overflowing in the upper part of the reactor body 1 where the cross-sectional area increases. Is more likely.

  In addition, when the waste liquid flows in from the lower side of the reactor main body 1 and passes through the reactor main body 1, In is recovered from the metal particles made of Zn by a cementation reaction. The concentration of the metal to be recovered in the waste liquid decreases as it goes to the point. However, in this embodiment, it is recognized that finer metal particles are present in the upper part of the reactor main body 1 and that the number of metal particles is increased by gradually decreasing the upward flow velocity of the waste liquid. The total surface area of the metal particles increases toward the top of 1. As a result, the reaction rate of the cementation reaction (efficiency of deposition of the recovery target metal) is improved, so that the recovery target metal is efficiently recovered even in the upper part of the reactor body 1 where the concentration of the recovery target metal is lower. It becomes possible to do.

(Embodiment 2)
In the present embodiment, the structure of the reactor main body 1 is different from that of the first embodiment. That is, in this embodiment, as shown in FIG. 3, the entire peripheral surface of the reactor body 1 is formed to be tapered upward, and the cross-sectional area of the reactor body 1 is continuously increased upward. It is configured. This is different from the case of the first embodiment in which the cross-sectional area of the reactor body 1 discontinuously increases upward. Since the cross-sectional area is not discontinuous and is configured to continuously increase upward, in this embodiment, the reactor upper part 2, the reactor intermediate part 3, and the reactor lower part 4 are provided as in the first embodiment. It is not configured in such a way.

  However, the ultrasonic oscillators 11a, 11b, and 11c are common to the first embodiment in that the ultrasonic oscillators 11a, 11b, and 11c are provided at three locations from the upper part to the lower part of the reactor body 1. Therefore, also in this embodiment, as in the first embodiment, the recovery target metal deposited on the metal particles can be forcibly separated by the ultrasonic waves oscillated from the ultrasonic oscillators 11a, 11b, and 11c. The effect that can be obtained.

  In addition, although there is a difference between discontinuous and continuous, this embodiment is common to Embodiment 1 in that the cross-sectional area is configured to increase upward. In this case, the fine metal particles having a reduced particle size are held at the upper part of the reactor main body 1 to prevent inadvertent overflow, and the upper part of the reactor main body 1 at which the concentration of the metal to be collected is low. In this case, there is an effect that the recovery target metal can be efficiently recovered.

(Embodiment 3)
The reactor main body 1 of this embodiment is the same as that of the first and second embodiments in that it is vertically long, but is formed so that the cross-sectional area is the same in the vertical direction as shown in FIGS. 4 and 5. In this respect, the second embodiment is different from the first and second embodiments that are configured such that the cross-sectional area increases upward.

  Also in the present embodiment, as in the first embodiment, the inflow chamber 7 is provided on the lower side of the reactor body 1 and the upper chamber 9 is provided on the upper side of the reactor body 1. The shape is different from that of the first embodiment formed in a substantially conical shape. That is, the upper chamber 9 is formed in a shallow cylindrical shape as shown in FIGS. 4 and 5, and the inflow chamber 7 includes a central cylinder portion 20 and the central cylinder as shown in FIGS. 6 and 7. It is formed in the shape which consists of the side cylinder parts 21 and 21 provided in the right and left in communication with the part 20.

  In the present embodiment, the inflow pipes 8 and 8 are respectively provided on the distal end sides of the side tube portions 21 and 21 of the inflow chamber 7. Further, two baffle plates 22 and 23 are provided in the longitudinal direction in the side tube portions 21 and 21 of the inflow chamber 7, and the liquid to be treated flowing in from the inflow pipes 8 and 8 is supplied to these baffle plates. It is comprised so that a flow may be disturbed by 22 and 23 (FIG. 7).

The upper chamber 9 is composed of an inner cylinder 9a and an outer cylinder 9b as shown in FIG. 5, and the upper chamber 9a is externally fitted to the upper portion of the reactor body 1 as shown in FIG. 9 is attached to the reactor body 1. Further, the discharge pipe 10 is attached to a position below the upper chamber 9 and between the inner cylinder 9a and the outer cylinder 9b.
As a result of such a configuration, the liquid to be treated that flows upward in the reactor body 1 overflows from the upper opening of the inner cylinder 9a between the outer cylinder 9b and the inner cylinder 9a, and from the discharge pipe 10 It will be discharged to the outside.

  Further, the metal particles for causing the cementation reaction are introduced from the upper opening of the inner cylinder 9a. The liquid to be treated rises in the vertical direction until the waste liquid flowing in from the inflow pipe 8 of the inflow chamber 7 reaches the discharge pipe 10 of the upper chamber 9 to form a fluidized bed of metal particles. The point that the cementation reaction between the input metal and the metal to be recovered occurs in the entire reactor body 1 is the same as in the first and second embodiments.

  Furthermore, also in this embodiment, an ultrasonic oscillator is employed as a stripping means for stripping the metal to be collected, which is a metal contained in the waste liquid and deposited on the metal particles by the cementation reaction. That is, in this embodiment, four ultrasonic oscillators 11 a, 11 b, 11 c, and 11 d are attached to the outer peripheral surface of the reactor main body 1. The four ultrasonic oscillators 11a, 11b, 11c, and 11d are all attached to the reactor main body 1 at an angle of about 45 degrees with respect to the horizontal plane, and two of these ultrasonic oscillators 11a and 11c are attached in the same direction, and the other two ultrasonic oscillators 11b and 11d are attached so as to face in opposite directions.

Also in the present embodiment, a waste liquid is used as the liquid to be treated. The waste liquid contains, for example, the same In ions as in the first embodiment, and nitrate ions (NO ₃ ⁻ ) and oxalate ions (C ₂ O). ₄ ) Cleaning waste liquid of aluminum target material containing ^F ) or FPD etching waste liquid using nitric acid or oxalic acid is used.

  In the case where indium is recovered by the indium recovery device of the present embodiment, first, waste liquid flows into the reactor main body 1 from the inflow pipe 8 through the inflow chamber 7. In this case, the inflow chamber 7 is composed of the central cylindrical portion 20 and the side cylindrical portions 21 and 21 as described above, and the side cylindrical portions 21 and 21 are provided with two baffle plates 22 and 23 in the vertical direction. Therefore, the waste liquid flowing in from the inflow pipes 8 and 8 attached to the side cylinder portion 21 in a horizontal direction does not flow in the horizontal direction at once, but the baffle plate 22 provided in the vertical direction, Then, the gas flows into the central cylindrical portion 20 while alternately flowing up and down in the side cylindrical portion 21 along the flow path 23, and flows upward from the central cylindrical portion 20 toward the reactor body 1.

  Accordingly, the waste liquid flowing in from the inflow pipes 8 and 8 is disturbed by the baffle plates 22 and 23 and is easily circulated upward in the reactor main body 1 without causing a drift. If necessary, for example, a cylindrical basket containing glass or ceramic balls can be installed in the inflow chamber 7, thereby making it possible to prevent drifting more reliably.

  The action of so-called cementation reaction based on the difference in ionization tendency between In contained in the waste liquid and the metal particles Zn and Al to be added, the action of stirring by the ultrasonic oscillator and the peeling of the metal, etc. This is the same as the above embodiment, and detailed description thereof is omitted.

(Embodiment 4)
In this embodiment, instead of the means for vibrating by the ultrasonic wave oscillated by the ultrasonic oscillators of the first to third embodiments as a means for separating the deposited metal to be collected from the metal particles, a gas such as air is used. A means utilizing a so-called air lift action that blows and stirs is employed. That is, in the present embodiment, as shown in FIG. 8, a cylindrical portion 25 is provided in the approximate center of the reactor body 1, and a gas inflow pipe 26 is connected to the lower portion of the cylindrical portion 25. A gas inlet 27, which is an opening on one end side of the gas inflow pipe 26, protrudes to the outside of the reactor body 1, and an opening 28 on the other end side of the gas inflow pipe 26 is in communication with the cylindrical portion 25. ing. A baffle plate 30 is provided below the lower opening 29 of the cylindrical portion 25.

  In the present embodiment, the reactor main body 1 is formed in a substantially cylindrical shape as in the third embodiment, and the inflow chamber 7 is provided in the lower portion of the reactor main body 1 as in the first to third embodiments. An upper chamber is provided at the top. In FIG. 8, however, the discharge pipe 10 is shown, but the upper chamber is not shown.

  The same type of waste liquid as that of the first to third embodiments is used as the type of waste liquid to be used and the metal particles to be introduced.

  As described above, metal particles having an average particle diameter of 0.1 to 8 mm can be used. However, when the metal particles are Al, those having a mean particle diameter of 1.5 to 5.5 mm are preferable. In that case, a thickness of 1.5 to 4.0 mm is preferable. This is because when Zn particles exceed 4.0 mm, and when Al particles exceed 5.5 mm, the flow rate necessary for flowing these particles increases and the amount of gas blown increases. On the other hand, since the particle size of the metal particles gradually decreases due to the cementation reaction, the metal particles may flow out of the reactor body 1 together with the treatment liquid when the initial particle size of the metal particles is small. However, from this viewpoint, in the case of Zn particles or Al particles, it is preferably 1.5 mm or more.

  Then, the method for recovering indium by the indium recovery device of the present embodiment will be described. First, the waste liquid flows into the reactor body 1 through the inflow chamber 7 as in the above embodiments, and the metal particles are discharged from the upper chamber. . Further, the gas is caused to flow into the cylindrical portion 25 through the gas inflow pipe 26. Thereby, the specific gravity of the mixed portion of the gas and water in the cylindrical portion 25 is lowered, and the liquid is pushed up together with the gas.

  In this way, by flowing the gas into the cylindrical portion 25 and causing the gas to flow upward, the liquid to be treated in the cylindrical portion 25 also flows upward. As described above, the liquid to be treated flows through the inside of the cylindrical portion 25, but a pressure difference is generated between the inside and the outside of the cylindrical portion 25, so the flow rate of the liquid to be treated is also different between the inside and outside of the cylindrical portion 25. As a result, the metal particles are agitated in the reactor main body 1, and the In deposited on the surface of the metal particles is peeled off.

  In this case, In, which is the metal to be collected in the present embodiment, precipitates in a sponge form, and therefore has poor adhesion to metal particles such as Zn, and therefore is forced by ultrasonic vibration as in the first to third embodiments. Inherently peels In from metal particles even without using a means for forcibly peeling using a means for automatically peeling, even with a stirring means that simply uses the air lift action as in this embodiment. Can be made. That is, it is possible to recover In with an apparatus having simple and low energy means.

  The action of so-called cementation reaction based on the difference in ionization tendency between In contained in the waste liquid and the charged metal particles Zn and Al is the same as in the above embodiment, and the detailed description thereof is as follows. Omitted.

  After precipitation of In on the surface of Zn particles or Al particles by such a cementation reaction, the precipitated In was peeled off from the Zn particles or Al particles by stirring using the air lift action as described above, and was peeled off. In is discharged to the outside of the reactor main body 1 through the discharge pipe 10 and collected.

  In the present embodiment, since the baffle plate 30 is provided below the lower opening 29 of the cylindrical portion 25, the waste water flowing from the inflow chamber 7 may flow directly into the cylindrical portion 25. However, the flow rate of the liquid to be treated in the cylindrical portion 25 is preferably prevented from being extremely increased by hitting the baffle plate 30.

(Embodiment 5)
In the present embodiment, air jet agitation or water jet agitation is adopted as means for separating the metal to be collected from the metal particles, and this is different from the above-described Embodiments 1 to 4. That is, in this embodiment, as shown in FIG. 9, the jet stirring jetting tool 31 is attached to the peripheral surface portion of the reactor main body 1, and air or water is jetted from the jet stirring jetting tool 31, and the reactor main body 1 In this configuration, fine bubbles are generated. That is, air jet agitation means that a gas such as air is ejected to generate fine bubbles, and water jet agitation means that a liquid such as water is ejected to generate fine bubbles.

  Since the shape of the reactor main body 1 and the configuration in which the inflow chamber 7 and the discharge pipe 10 are provided are the same as those in the above embodiment, the description thereof is omitted. Further, since the metal particles to be input, the type of waste liquid to be used, the action of cementation reaction, and the like are the same as those in the above embodiment, detailed description thereof is omitted.

  In the present embodiment, a gas such as air or water (for example, a treatment liquid) is ejected from the jet stirring jetting tool 31 to generate turbulent flow in the reactor main body 1, and the turbulent flow causes the turbulent flow in the reactor main body 1. The metal particles are agitated, whereby In deposited on the surface of the metal particles is peeled off.

  Also in this embodiment, since the recovery target metal In is poor in adhesion to metal particles such as Zn, means for forcibly peeling by ultrasonic vibration as in Embodiments 1 to 3, Even if the means for forcibly separating using the electromagnet as in the fourth embodiment is not adopted, In can be relatively easily separated from the metal particles by simply performing air jet or water jet stirring. it can. That is, it is possible to recover In with an apparatus having a simple and low energy stirring means.

(Embodiment 6)
In the present embodiment, as a means for peeling the metal to be collected from the metal particles, a means by a solid-liquid transport pump stirring is adopted, which is different from the above-described Embodiments 1 to 5. That is, in this embodiment, as shown in FIG. 10, a flow path 32 and a pump 33 for circulating and transporting the liquid to be treated and the metal particles in the reactor main body 1 and the pump 33 are provided outside the reactor main body 1, A means for stirring the metal particles by circulating and transporting the treatment liquid and the metal particles is employed.

  Since the shape of the reactor main body 1 and the configuration in which the inflow chamber 7 and the discharge pipe 10 are provided are the same as those in the fourth and fifth embodiments, description thereof will be omitted. Further, since the metal particles to be input, the type of waste liquid to be used, the action of cementation reaction, and the like are the same as those in the above embodiment, detailed description thereof is omitted.

  In the present embodiment, the liquid to be treated is discharged from the reactor main body 1 together with the metal particles to the flow path 32 by the pump 33, circulates through the flow path 32, and is returned to the reactor main body 1 again. The metal particles in the reactor main body 1 are agitated, whereby In deposited on the surface of the metal particles is peeled off.

  Also in this embodiment, since the recovery target metal In is poor in adhesion to metal particles such as Zn, means for forcibly peeling by ultrasonic vibration as in Embodiments 1 to 3 above is adopted. Even if it does not do, In can be peeled comparatively easily from a metal particle by the means of only stirring a solid-liquid transport pump using the pump 33 or the flow path 32. That is, it is possible to recover In with an apparatus having simple and low energy means.

(Other embodiments)
In the above-described embodiment, the case where the waste liquid (liquid to be treated) is applied to the cleaning waste liquid of the aluminum target material, the FPD etching waste liquid, or the like has been described, but the type of the waste liquid is not limited thereto. In the present invention, the liquid to be treated is mainly used as a liquid to be treated, but the liquid to be treated other than the waste liquid, for example, a metal-containing solid waste is brought into contact with a chemical such as an acid to dissolve the metal to be recovered. It is also possible to apply to an aqueous solution obtained by ionization. In short, the present invention can be applied to any liquid to be treated that contains In ions and nitrate ions (NO ₃ ⁻ ) or oxalate ions (C ₂ O ₄ ²⁻ ). In addition, the type of metal on which In is deposited is not limited to Zn and Al in the embodiment, and a metal having a higher ionization tendency than In may be used.
In addition, when recovering In from the liquid to be treated containing oxalate ions, it is preferable to use Al as the deposited metal. This is because when Zn is used, zinc oxalate is generated and deposited as fine particles, and zinc oxalate is recovered at the filter portion, which hinders the In recovery process.

  Furthermore, in the said embodiment, chlorides, such as sodium chloride and potassium chloride, were used as a chlorine ion source to add, However, Not only such a chloride but hydrochloric acid can also be used. However, when hydrochloric acid is used, the acid concentration of the liquid to be treated becomes high, the dissolution reaction of the metal particles used is promoted, and hydrogen gas is generated. This leads to an increase in the consumption of unnecessary metal particles and an increase in the amount of hydrogen gas generated, which in turn leads to an increase in running cost. Therefore, it is preferable to use the chloride of the above embodiment as the chlorine ion source.

On the other hand, if the reduction and precipitation reaction of In proceeds by adding a chlorine ion source, the metal ions to be used are dissolved and hydrogen gas is always generated, so that H ^{+ in} the solution is consumed and the pH of the liquid to be treated is increased. Rises. When the pH is higher than about 1.5, In in the liquid to be treated becomes a hydroxide and precipitates, so that it is necessary to add an acid to lower the pH. In such a case, it is preferable to add hydrochloric acid.

  In the above embodiment, as shown in FIG. 1, since the used processing liquid is returned to the adjustment tank 12, the chlorine ion source remaining in the processing liquid is changed to the liquid to be processed (waste liquid). As a result, it is possible to reduce the amount of additional chloride necessary for the next In recovery process, but the treatment liquid is used as in the above embodiment. Returning and reusing the chlorine ion source is not a requirement for the present invention. Furthermore, in the said embodiment, although the adjustment tank 12 for adding a chlorine ion source was provided separately from the reactor main body 1, not only this but a chlorine ion source may be added and adjusted directly to the reactor main body 1. Is possible.

  Moreover, in this embodiment, although the average particle diameter of a metal particle shall be about 2 mm, the average particle diameter of a metal particle is not limited to this embodiment, and the point should just be 0.1-8 mm. When the thickness is less than 0.1 mm, the cementation reaction is not always preferably performed, and there is a possibility that the recovery target metal peeled from the metal particles may not be easily recovered. The number of metal particles that can be held in the body decreases, and as a result, the total surface area of the metal particles may decrease and the efficiency of the precipitation reaction may decrease, and the flow rate needs to be increased in order to cause the metal particles to flow. This is because it is necessary to increase the reactor size (reactor height) in order to maintain the necessary reaction time. From this viewpoint, the thickness is more preferably 0.5 to 6 mm. Furthermore, in order to improve the fluidity and reactivity in the reactor main body and to facilitate the holding in the reactor main body, the range of 1.0 to 2.0 mm is more preferable. The average particle diameter of the metal particles is measured by an image analysis method, a JIS Z 8801 sieving test method, etc. as described above. For example, Millitrack JPA manufactured by Nikkiso Co., Ltd. is used for the measurement of the average particle diameter by the image analysis method. Further, in the JIS sieving method, when the average particle size is in the range of 1 to 2 mm, for example, metal particles that are on a 1000 μm sieve are used under a nominal size of 2000 μm sieve.

  Furthermore, the uniformity of the metal particles is preferably less than 5 from the viewpoints of processing efficiency and operation control. Here, the uniformity of the metal particles refers to a transmittance curve formed by particle size distribution measurement or sieving or the like (the percentage of the mass of particles smaller than a certain particle size with respect to the total sample mass, that is, the transmittance is drawn for a certain particle size. In this case, the value obtained by dividing the 60% particle size under the screen by the 10% particle size under the screen. It represents the width of the particle size distribution.

  Furthermore, in this embodiment, although the metal particle utilized the metal single-piece | unit, an alloy may be sufficient.

  Further, in the first and second embodiments, since the cross-sectional area of the reactor main body 1 is formed so as to increase toward the upper part, the above-described preferable effect is obtained. However, the reactor main body 1 is formed in this way. These are not essential conditions for the present invention. As in the third, fourth, fifth, and sixth embodiments, the reactor main body 1 may be formed so that the cross-sectional area is the same and the whole is substantially cylindrical.

  Furthermore, the means for peeling the metal to be collected from the metal particles is not limited to the means in the first to sixth embodiments, and other means may be used. Furthermore, from the point that the metal for precipitation can be effectively reused while easily separating and recovering the metal to be recovered, the metal to be recovered is separated from the metal for precipitation in the reactor. However, the present invention is not limited to this. The recovery target metal may be recovered in a state where the recovery target metal is deposited on the deposition metal. In the first to sixth embodiments, metal particles are used as the deposition metal. However, the present invention is not limited to this, and a metal wire, a metal wire processed into a mesh shape, a plate-like metal, or the like may be used. .

Example 1
A nitric acid solution in which indium was dissolved was prepared as a simulation solution of the waste liquid. The simulation solution used was a solution in which In was dissolved in a 2.8% nitric acid solution at a concentration of 400 mg / L. This was put into a 1 L beaker, 50 g of sodium chloride was first added, and In alloy recovery processing was started using Al metal particles having an average particle diameter of 2 mm by an image analysis method. With the treatment, H ₂ gas and mainly NO ₂ gas were generated. Since H ⁺ is consumed as H ₂ gas with the treatment, the pH rises, so the pH in the solution is measured with a pH meter, and hydrochloric acid is added so that the pH does not exceed 1.5. Stirring was carried out for 120 minutes to such an extent that it did not occur. The In alloy deposited on the Al metal particles was in the form of a sponge and aggregated during the stirring process to form a large lump, so that it could be easily peeled and collected by ultrasonic treatment. The ultrasonic treatment was performed once every 2 minutes, and each was performed for 2 seconds. Incidentally, the obtained In alloy had a size of about several hundred μm to several mm. If it becomes such a large lump, it can be recovered even with an inexpensive filter such as a bag filter.

  By adding 1 L of a new stock solution (indium-containing nitric acid solution) to the liquid after the above treatment, adding 25 g of sodium chloride and starting the treatment, the treatment can be performed in the same process as described above. Therefore, the amount of chloride added can be reduced, and the processing cost can be reduced.

  As a result of the test under the above conditions, the recovery rate of In from the solution was 95%, and a very good result was obtained.

(Example 2)
The test was performed under the same conditions except that Zn metal particles were used instead of the Al metal particles of Example 1 above. Also in this example, a good result was obtained that the recovery rate of In was 90%.

(Example 3)
An oxalic acid solution in which indium was dissolved was prepared as a waste liquid simulation solution. The simulation solution used was a solution of In dissolved in a 5% oxalic acid solution at a concentration of 350 mL. This was put into a 1 L beaker, 12 g of sodium chloride was first added, and In alloy recovery processing was started using Al metal particles having an average particle diameter of 2 mm by an image analysis method. H ₂ gas was generated along with the treatment. Since H ⁺ is consumed as H ₂ gas with the treatment, the pH rises, so the pH in the solution is measured with a pH meter, and hydrochloric acid is added so that the pH does not exceed 1.5. Stirring was performed for 180 minutes to such an extent that it did not occur. The In alloy deposited on the Al metal particles was in the form of a sponge and aggregated during the stirring process to form a large lump, so that it could be easily peeled and collected by ultrasonic treatment. The ultrasonic treatment was performed once every 2 minutes, and each was performed for 2 seconds. As a result, the recovery rate of In from the solution was 20%. The obtained In alloy was about several hundred μm to several mm in size. If it becomes such a large lump, it can be recovered even with an inexpensive filter such as a bag filter.

Example 4
The test was conducted under the same conditions except that 10 g of 35% hydrochloric acid was used in place of the sodium chloride in Example 3. In this example, a good result that the recovery rate of In was 40% was obtained.

(Comparative Example 1)
The same treatment was performed by adding only Al metal particles to the simulated solution prepared in Example 1 above without adding sodium chloride. In addition, since nitrate ion and a part of Al metal particle reacted, since pH became 1.5 or more, pH adjustment was performed using the sulfuric acid. Although the solution was stirred for 120 minutes, no In alloy precipitation was observed on the surface of the Al metal particles.

(Comparative Example 2)
The test was performed under the same conditions except that zinc metal particles were used instead of the Al metal particles of Comparative Example 1 above. No In precipitation was observed even in this comparative example.

(Comparative Example 3)
The same treatment was performed by adding only Al metal particles to the simulated solution prepared in Example 3 above without adding sodium chloride. In addition, since nitrate ion and a part of Al metal particle reacted, since pH became 1.5 or more, pH adjustment was performed using the sulfuric acid. The solution was stirred for 180 minutes, but no In alloy precipitation was observed on the surface of the Al metal particles.

The schematic block diagram of the collection | recovery apparatus of indium as one Embodiment. The schematic block diagram which shows a reactor main body. The schematic block diagram of the reactor main body of other embodiment. The schematic perspective view of the reactor main body of other embodiment. The schematic sectional drawing of the embodiment. The schematic plan view of the chamber for inflow of the embodiment. The AA line expanded sectional view of FIG. The schematic front view of the reactor main body of other embodiment. The schematic front view of the reactor main body of other embodiment. The schematic front view of the reactor main body of other embodiment.

Explanation of symbols

  1 ... Reactor body 12 ... Adjustment tank

Claims (8)

  A method for recovering indium from a liquid to be treated which contains indium in an ionic state and contains at least one of nitrate ion and oxalate ion, and has a higher ionization tendency than indium. And a chlorine ion source is added to the liquid to be treated, and indium contained in the liquid to be treated is precipitated on the surface of the deposition metal due to a difference in ionization tendency. To recover indium.   A method for recovering indium from a liquid to be treated containing indium in an ionic state and containing at least one of nitrate ions and oxalate ions, wherein the liquid to be treated is prepared in a regulating tank (12). And a chlorine ion source is added to the adjustment tank (12), and then the liquid to be treated in the adjustment tank (12) flows into the reactor main body, and the reactor main body contains more than indium. The indium is recovered by adding a deposition metal having a large ionization tendency and precipitating indium contained in the liquid to be treated on the surface of the deposition metal due to a difference in ionization tendency. Collection method.   The method for recovering indium according to claim 1 or 2, wherein the indium deposited on the surface of the depositing metal is separated from the depositing metal and collected.   The method for recovering indium according to any one of claims 1 to 3, wherein the processing liquid after recovering indium from the deposition metal is added to the liquid to be processed which is a stock solution, and the processing is performed again.   Indium is contained in an ionic state, and at least one of nitrate ion or oxalate ion is contained, and a treatment liquid adjusted by adding a chlorine ion source flows in, and the ionization tendency is larger than indium. It comprises a reactor main body for performing a metal precipitation reaction by adding a metal for precipitation and precipitating indium contained in the liquid to be treated on the surface of the metal for precipitation due to a difference in ionization tendency. Indium recovery equipment.   An adjustment tank (12) for containing a liquid to be treated containing indium in an ionic state and containing at least one of nitrate ion or oxalate ion, and adjusting by adding a chlorine ion source, and the adjustment In addition to flowing in the liquid to be treated in the tank (12), a deposition metal having a larger ionization tendency than indium is added, and the indium contained in the liquid to be treated is caused by the difference in ionization tendency. An indium recovery apparatus comprising a reactor main body for performing a metal deposition reaction to be deposited on a surface.   The indium recovery apparatus according to claim 5 or 6, further comprising a stripping means for stripping indium deposited on the deposition metal surface from the deposition metal.   The indium according to any one of claims 5 to 7, wherein a return flow path is provided so that the treatment liquid after recovering indium from the deposition metal is added to the liquid to be treated as a stock solution and the treatment is performed again. Recovery equipment.

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