WO2007015392A1

WO2007015392A1 - Method and apparatus for recovering indium from waste liquid crystal display

Info

Publication number: WO2007015392A1
Application number: PCT/JP2006/314626
Authority: WO
Inventors: Toshiaki Muratani; Takamichi Honma; Tomoharu Maeseto; Mitsushige Shimada
Original assignee: Kobelco Eco-Solutions Co., Ltd.; Sharp Kabushiki Kaisha
Priority date: 2005-08-04
Filing date: 2006-07-25
Publication date: 2007-02-08
Also published as: TWI385255B; KR20080031661A; US20100101367A1; CN100554454C; JPWO2007015392A1; CN101133172A; TW200712219A

Abstract

This invention provides a method and apparatus for recovering In in the form of an alloy or a metal simple substance as a valuable material from waste LCD. In the In recovery method and apparatus, there is no need to recover In as indium hydroxide, and In can be recovered as a valuable metal. Accordingly, unlike the case of indium hydroxide, the recovery does not suffer from poor handling, and In can easily be recovered through a filter or the like with significantly improved In recovery. The In recovery method is characterized by comprising crushing waste LCD containing indium tin oxide, dissolving indium tin oxide from the crushed waste LCD with an acid to give an indium compound-containing solution, allowing the solution to flow into a reactor for recovery and, further, adding particles of a metal having a larger ionization tendency than In into the reactor for recovery, fluidizing the metal particles, precipitating In or an In alloy contained in the indium compound-containing solution onto the surface of the metal particles, then separating the precipitated In or In alloy from the metal particles by separation means, and separating and recovering the separated solid In or In alloy from the liquid component.

Description

Specification

Method and apparatus for recovering indium from waste liquid crystal display

Technical field

[0001] The present invention relates to a method and apparatus for recovering indium from a discarded liquid crystal display, and more specifically, a discarded liquid crystal television, a mobile phone, a portable game machine, etc., or a liquid crystal discharged as a defective product in a production process. The present invention relates to a method and apparatus for recovering valuable indium (In) from a display (hereinafter also referred to as “waste LCD”) as an alloy or a single metal.

Background art

[0002] An indium tin oxide (ITO) film is used as a transparent electrode in a liquid crystal display (hereinafter also referred to as LCD!). The ITO film is mainly formed by sputtering, but In is used as the target. In is a rare metal obtained during the zinc refining process, and its death has been feared in recent years. Waste LCD contains about 300mgZL of In, and with the Withering of In, it is required to collect In during the recycling process.

[0003] Attempts have been made to collect In in waste LCDs that meet such demands. For example, there is an invention described in Non-Patent Document 1 below. The present invention relates to a fluidized bed LCD processing system, and the fluidized bed LCD processing system comprises a fluidized bed processing section, a cyclone, a cooler, a high temperature bag filter, a catalyst fluidized bed, and a water washing tower. In, which is mechanically separated by the silicon sand of the fluid medium in the processing section, is accumulated in the fluid medium. However, in the method using this processing system, about 60% of the waste LCD accumulates in the fluid medium and the rest is collected by the bag filter, so the indium recovery rate is about 60% overall, and the recovery is The rate was as low as about 60%.

[0004] Non-Patent Document 1: Monthly Display April 2002 P36-46

[0005] In order to increase the low recovery rate of the dry process as described above, a method using a wet process has also been developed. For example, Patent Document 1 below is a method in which ITO is dissolved in an acid such as nitric acid or hydrochloric acid, impurities such as Sn are precipitated and removed, neutralized by adding ammonia, and recovered as indium hydroxide. .

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2000-128531 However, according to the wet processing method as described above, the filterability of indium hydroxide obtained by the treatment is poor, the operation takes a long time, and the indium hydroxide obtained by neutralization or the like is used. There is a problem that the nature of the system changes.

Disclosure of the invention

Problems to be solved by the invention

[0008] The present invention has been made to solve such a problem, and it is possible to recover In as a valuable metal, which does not need to be recovered in the state of hydroxide hydroxide as in the prior art. To provide an In recovery method and apparatus that can be easily recovered with a filter that does not have poor handling as in the case of indium hydroxide at the time of recovery, and the recovery rate of In is remarkably good. Is an issue.

Means for solving the problem

[0009] The present invention has been made to solve such a problem, and the invention according to claim 1 relating to a method for recovering In from waste LCD includes a waste liquid crystal display containing indium tin oxide. The crushed waste liquid crystal display also uses acid to dissolve indium tin oxide to obtain an indium compound-containing solution, which flows into the recovery reactor and has an ionic value higher than that of indium in the recovery reactor. Metal particles that also have a strong metal force are added, the metal particles are flowed, and indium or an indium alloy contained in the indium compound-containing solution is deposited on the surface of the metal particles, and then the metal is separated by a peeling means. Particle force The deposited indium or indium alloy is peeled off, and the peeled solid indium or indium alloy is liquidized. It is characterized by separating the components and collecting them.

[0010] The invention according to claim 2 is the method for recovering indium from the waste liquid crystal display according to claim 1, wherein the metal particles having a metal force having a larger ionic tendency than indium are zinc particles or aluminum particles. It is characterized by being. Further, the invention of claim 3 is the method for recovering indium from the waste liquid crystal display according to claim 1 or 2, wherein the means for peeling off the indium or indium alloy deposited on the metal particles by the metal particle force, It is a means for vibrating metal particles by ultrasonic waves, or a means for stirring metal particles by an electromagnet and causing them to collide with each other. [0011] Further, the invention of claim 4 is an indium in which indium tin oxide is dissolved from the waste liquid crystal display by using the method for recovering indium from the waste liquid crystal display according to any of claims 1 to 3. Before flowing the compound-containing solution into the recovery reactor, the indium compound-containing solution is allowed to flow into the impurity removal reactor, and the ionic valence tendency is larger than that of impurity metals other than indium in the indium compound-containing solution! Then, metal particles made of metal are added into the impurity removal reactor to cause the metal particles to flow, and the impurity metal is deposited on the surface of the metal particles, and then the metal particle force is separated by a peeling means. Peeling and removing the deposited impurity metal

[0012] Furthermore, the invention according to claim 5 is the method for recovering indium of waste liquid crystal display power according to claim 4, wherein the means for separating the impurity metal deposited on the metal particles from the metal particles by ultrasonic waves It is a means for vibrating particles, or a means for stirring metal particles with an electromagnet and causing them to collide with each other. Furthermore, the invention described in claim 6 is characterized in that in the method for recovering indium from the waste liquid crystal display according to claim 4 or 5, the impurity metal is tin. Further, according to the seventh aspect of the present invention, in the method for recovering indium from the waste liquid crystal display according to any one of the fourth to sixth aspects, the metal particles made of a metal having a higher ionic tendency than an impurity metal are iron particles. It is a feature. Furthermore, the invention according to claim 8 is the method for recovering indium from the waste liquid crystal display according to claim 7, wherein an alkali is added to the solution containing the indium compound after removing the impurity metal, and iron is used as a hydroxide. It is characterized by removing the precipitate. Further, the invention according to claim 9 is a method in which an indium compound-containing solution is obtained by dissolving indium tin oxide using an acid from the waste liquid crystal display in a state where the waste liquid crystal display is contained in a bag. The waste liquid crystal display contained in the bag is washed and neutralized, and then dried.

[0013] The invention according to claim 10 further relates to an apparatus for recovering indium from a waste liquid crystal display, wherein a crusher for crushing a waste liquid crystal display containing indium tin oxide and an acid for the crushed waste liquid crystal display are used. And an indium dissolution apparatus for obtaining an indium compound-containing solution by dissolving indium tin oxide, and an indium dissolution apparatus obtained by the indium dissolution apparatus. An indium compound-containing solution is introduced, and the ionic valence tendency is larger than that of the indium. The metal precipitation reaction is performed by adding metal particles having metal power to deposit indium or an indium alloy on the surface of the metal particles. A separation reactor for separating the separated solid indium or indium alloy from the liquid component, a separation reactor for separating the deposited indium or indium alloy from the liquid, and a separating means for separating the separated indium or indium alloy from the liquid component. It is characterized by comprising.

[0014] Further, the invention according to claim 11 is the apparatus for recovering indium from the waste liquid crystal display according to claim 10, wherein the metal particles having a metal force having a larger ionic tendency than indium are zinc particles or aluminum particles. It is characterized by being. Further, the invention described in claim 12 is the indium recovery device for waste liquid crystal display power according to claim 10 or 11, wherein the means for peeling off the indium or indium alloy deposited on the metal particles includes: It is a means for vibrating metal particles by ultrasonic waves, or a means for stirring metal particles with an electromagnet and causing them to collide with each other.

[0015] Further, the invention according to claim 13 is an indium compound-containing solution obtained by an indium dissolution apparatus in addition to the indium recovery apparatus from the waste liquid crystal display according to any one of claims 10 to 12. And flowing metal particles having a higher ionic valence than the impurity metals other than indium in the indium compound-containing solution to cause the metal particles to flow, and allowing the impurity metals to flow on the surface of the metal particles. An impurity removing reactor having means for separating and removing the precipitated impurity metal by peeling off the metal particle force is provided on the upstream side of the recovery reactor.

[0016] Further, in the invention according to claim 14, in the apparatus for recovering indium from the waste liquid crystal display according to claim 13, the means for separating the impurity metal deposited on the metal particles from the metal particles by ultrasonic waves It is a means for vibrating particles, or a means for stirring metal particles with an electromagnet and causing them to collide with each other. Furthermore, the invention described in claim 15 is characterized in that in the indium recovery apparatus having the power for waste liquid crystal display according to claim 13 or 14, the impurity metal is tin.

[0017] Further, in the invention described in claim 16, the apparatus for recovering indium from the waste liquid crystal display described in claims 13 to 15 has a higher ionic tendency than the impurity metal! The metal particles are iron particles. Further, the invention described in claim 17 is the apparatus for recovering indium from the waste liquid crystal display according to claim 16, wherein the alkali is added to the indium-containing solution after removing the impurity metal, and iron is precipitated as a hydroxide. It is characterized by having a precipitation removing device for removing.

The invention's effect

[0018] As described above, the present invention provides a solution containing an indium compound by crushing a waste liquid crystal display (waste LCD) containing indium tin oxide, and dissolving the crushed waste LCD force using an acid to dissolve indium tin oxide. And flowing into the recovery reactor, adding metal particles having a metal force having a larger ionic valence than indium (In) into the recovery reactor, causing the metal particles to flow, and In or In alloy contained in the contained solution is deposited on the surface of the metal particles, and then the deposited In or In alloy is also peeled off by the peeling means, and the peeled solid In or In alloy is peeled off. Since the In alloy is separated and collected by liquid force, the waste LCD force can dissolve ITO easily and efficiently, and the ionization tendency is used to recover In from the solution in which In is dissolved. In other words, the combination of the cementation reaction and the stripping technology, that is, the use of metal particles increases the total surface area of the metal for the metal deposition reaction, improves the deposition reaction rate, and increases the growth of the deposited metal to some extent. Peeling with a peeling means always exposes a new metal surface and maintains the reaction rate, so the recovery rate of In from waste LCD is significantly higher than conventional dry and wet methods. If it can be improved, it has a positive effect. Incidentally, in the present invention, it was possible to obtain a high recovery rate of 80% or more with respect to the In recovery rate from the waste liquid.

[0019] In addition, since it is possible to recover In as a valuable metal that does not need to be recovered in the state of indium hydroxide as in the conventional wet method, the handling is not as good as in the case of indium hydroxide at the time of recovery. There is an effect that it can be easily collected with a filter.

[0020] Further, when a reactor for removing impurities that causes the same metal deposition reaction as that of the recovery reactor is provided on the front side of the recovery reactor, an indium compound in which waste LCD power indium oxide is dissolved Metals other than In contained in the containing solution, such as tin A metal having a higher ionic tendency than the impurity metal such as (Sn), for example, metal particles such as iron (Fe) is added and fluidized, and the impurity metal such as Sn contained in the waste liquid is added to the iron or the like. By depositing on the surface of the metal particles and then separating the impurity metal deposited from the metal particles by a stripping means, the impurity metal such as Sn can be suitably removed.

[0021] Accordingly, since the waste liquid can be supplied to the recovery reactor in a state where impurity metals other than In such as Sn are removed in advance, the purity of In recovered in the recovery reactor is further improved. There is an effect of doing. By the way, by installing such a reactor for removing impurities at the front side of the recovery reactor, it was possible to recover 95% or more highly purified In.

[0022] Further, when the impurity metal is removed using such a reactor for removing impurities, ions of the added metal such as iron are eluted, but an alkali is added by a subsequent precipitation removing apparatus. Then, by precipitating a metal such as iron as a hydroxide, the hydroxide such as iron can be removed in advance before the waste liquid is supplied to the recovery reactor 1. In this case, there is a risk that indium hydroxide is formed as a precipitate when the pH is high. However, the rate of precipitate formation is overwhelmingly faster with hydroxide and ferrous iron. Thus, indium hydroxide is not generated, and it is possible to supply the next recovery reactor with almost no loss of In. Even if a part of In is present in the solution as indium hydroxide, indium hydroxide is dissolved again by adjusting the pH in the next reactor for recovery, so the In recovery rate is reduced. I will not let you.

In addition, if the waste LCD is stored in the bag and subjected to In elution with acid, neutralization with washing, and drying, the fine waste LCD crushed in the waste LCD crushing process is knocked out. It is possible to perform consistent processing while it is housed inside, and to simplify processing as a whole. In addition, since it is not necessary to handle fine waste LCD pieces that accept the waste LCD crushing process power as powder, there is an effect that it will not be difficult to handle.

[0023] As described above, according to the present invention, it is possible to provide an In recovery method with a high recovery rate. Therefore, even when LCD recovery and recycling is required under the Home Appliance Recycling Law in the future, As an In recovery method in the recycling process at a recycling plant There is an actual advantage that the present invention can be applied.

Brief Description of Drawings

FIG. 1 is a schematic block diagram of an In recovery device for waste LCD power as one embodiment.

FIG. 2 is a schematic front view of an impurity removal reactor or a recovery reactor in the In recovery apparatus.

FIG. 3 is a schematic front view of an impurity removal reactor or a recovery reactor according to another embodiment.

FIG. 4 is a schematic front view of an impurity removal reactor or a recovery reactor according to another embodiment.

FIG. 5 is a schematic plan view of a slide board provided with an electromagnet used in the embodiment of FIG.

FIG. 6 is a schematic block diagram showing an In recovery apparatus according to another embodiment.

FIG. 7 is a schematic sectional view of an elution treatment apparatus in the same apparatus.

FIG. 8 is a schematic explanatory diagram of an apparatus used in the examples.

Explanation of symbols

[0025] 2 ... Reactor removal reactor 3 ... Precipitation removal device

4 ... Recovery reactor

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]

As shown in FIG. 1, the waste LCD force indium recovery device of this embodiment is composed of an indium dissolution device (hereinafter also referred to as an In dissolution device) 1 that dissolves ITO using hydrochloric acid as well as the waste LCD force. Impurity removing reactor 2 for adding iron particles (Fe particles) to the indium compound-containing solution dissolved in dissolving apparatus 1 to remove impurity metals other than In, and for removing the impurities Precipitation removal device 3 that precipitates and removes the Fe particles in the waste liquid from which impurity metals have been removed in reactor 2 as iron (Fe) hydroxide, and precipitation removal device 3 removes the precipitate of Fe hydroxide. And a recovery reactor 4 for recovering the generated waste liquid power In. Although not shown, a crusher for crushing the waste LCD is provided in the front stage of the In melting apparatus 1. In the present invention, crushing means crushing the waste LCD, and the size of the crushed pieces is not questionable. For example, crushing is generally recognized as meaning crushing into fine dust. Such a state is also included. [0028] The In dissolution apparatus 1 is for obtaining an indium compound-containing solution by dissolving In with crushed waste LCD and hydrochloric acid (hydrochloric acid aqueous solution). The indium compound-containing solution is prepared so that the In content is 100 to 300 mgZL. This indium compound-containing solution is prepared so that the concentration of hydrochloric acid is 20% and the pH of hydrochloric acid is 1.5.

[0029] The impurity removal reactor 2 is for removing Sn, which is an impurity, from the indium compound-containing solution, and includes a vertically long reactor body 5 as shown in FIG. As shown in the figure, the reactor main body 5 includes a reactor upper part 6, a reactor intermediate part 7, and a reactor lower part 8, which are connected via connecting parts 9 and 10, respectively. Reactor upper part 6, reactor intermediate part 7, and reactor lower part 8 are each formed to have the same width, but the cross-sectional area of reactor upper part 6 is formed to be larger than the cross-sectional area of reactor intermediate part 7. The cross-sectional area is larger than the cross-sectional area of the lower reactor 8. As a result, the cross-sectional area of the reactor body 5 as a whole is configured to discontinuously increase upward. The connecting portions 9 and 10 are formed in a tapered shape that is wide upward.

[0030] A substantially conical inflow chamber 11 for inflow of an indium compound-containing solution to be processed is provided below the reactor lower part 8, and an inflow pipe 12 is provided at the lower part thereof. Yes. Although not shown, the inflow pipe 12 is provided with a check valve. In addition, an upper chamber 13 is provided on the upper side of the upper part 6 of the reactor, and a discharge pipe 14 is provided on the side to deposit Sn, which is an impurity metal, on metal particles (Fe particles) and discharge it. It is. The upper chamber 13 is a part for discharging Sn together with Fe particles by such an exhaust pipe 14, and based on the difference in ionization tendency with Sn to be removed as impurities, it is a so-called cementation. It is also the part where Fe particles are added to cause the reaction (metal precipitation reaction). Actually, the cementation reaction between Fe and Sn occurs in the entire reactor body 1.

[0031] Then, while the indium compound-containing solution flowing from the inflow pipe 12 reaches the discharge pipe 14, the waste liquid rises in the vertical direction and forms a fluidized bed of Fe particles. Yes. Further, it is an impurity metal contained in the indium compound-containing solution, and the Sn precipitated on the Fe particles by the cementation reaction is peeled off. Ultrasonic oscillators 15a, 15b, and 15c as peeling means are provided in the reactor upper part 6, the reactor middle part 7, and the reactor lower part 8, respectively.

In the present embodiment, Fe particles are used as the metal particles to be input as described above. The average particle diameter of Fe particles is preferably 0.1 to 8 mm, but in this embodiment, an average particle diameter of about 3 mm is used. The average particle diameter is measured by an image analysis method or a WIS Z 8801 screening test method.

The precipitation removing apparatus 3 is for removing the Fe particles as a hydroxide by precipitation. Hydroxide precipitation is removed by adding an alkali (alkaline solution) such as sodium hydroxide. The pH of the waste liquid in the sediment removal device 3 is adjusted to 8-9.

[0033] The recovery reactor 4 is for recovering the indium compound-containing solution force In after removing Sn, which is an impurity, and precipitating and removing Fe as a hydroxide, as described above. It has the same construction power as the reactor 2 for removal. That is, as shown in FIG. 2, the reactor main body 5 is configured such that the reactor upper part 6, the reactor intermediate part 7, and the reactor lower part 8 are connected through the connection parts 9 and 10. In the recovery reactor 4, the pH is adjusted to 1.5 or lower.

[0034] The inflow chamber 11, the inflow pipe 12, the upper chamber 13, the discharge pipe 14, and the ultrasonic oscillators 15a, 15b, 15c are the reactor upper part 6, the reactor intermediate part 7, and The point provided at the lower part 8 of the reactor is the same as the reactor 2 for removing impurities.

[0035] A method for recovering In from waste LCD using the In recovery device for waste LCD having such a configuration will now be described. First, the waste LCD is crushed by a crusher (not shown). Supply the crushed waste LCD to the In dissolution apparatus 1. Hydrochloric acid (hydrochloric acid solution) is added to the In dissolution apparatus 1, and the waste LCD power In is eluted by the hydrochloric acid, and an indium compound-containing solution having an In content of 100 to 300 mgZL is contained in the In dissolution apparatus 1. can get.

Next, this indium compound-containing solution is supplied to the impurity removing reactor 2. The indium compound-containing solution supplied to the impurity removing reactor 2 flows into the reactor body 5 from the inflow pipe 12 of the impurity removing reactor 2 through the inflow chamber 11. On the other hand, the gold used to cause a cementation reaction from the upper chamber 13. Add metal particles (Fe particles). In the reactor main body 5, the indium compound-containing solution that has flowed in rises in the vertical direction, while the indium compound-containing solution and the Fe particles introduced from the upper chamber 13 flow so as to form a fluidized bed. State.

[0037] And contained in the solution containing the indium compound! Based on the difference in ionization tendency between the impurity metal other than In, that is, Sn and the input metal particle Fe. Causes a cementation reaction. To explain this in more detail, the reduction reaction of each metal ion is as follows, and the standard electrode potential (E °) of each metal ion is shown.

[0038] Fe ²⁺ + 2e → Fe… hi) 0.44V

Sn ²⁺ + 2e → Sn--(2) —0.14V

As is clear from the above (1) and (2), the standard electrode potential of Fe ²⁺ is smaller than that of Sn ²⁺ . In other words, the ionization tendency of Fe is larger than Sn. For this reason, in the fluidized state as described above, Fe having a high ionization tendency becomes Fe ²⁺ (reaction opposite to the above equation (1)) and is eluted in the indium compound-containing solution, together with the indium compound. Sn ²⁺ becomes Sn and precipitates on the surface of Fe particles.

[0040] Then, after precipitation of Sn on the surface of the Fe particles by such a cementation reaction, the ultrasonic oscillators 15a, 15b, 15c are operated. By operating the ultrasonic oscillators 15a, 15b, and 15c, the ultrasonic waves oscillated from the ultrasonic oscillators 15a, 15b, and 15c generate vibration force and stirring force on the Fe particles on which the Sn is deposited. As a result, Sn that has been deposited is forcibly separated from the Fe particles.

[0041] The Sn thus peeled is discharged from the upper chamber 13 through the discharge pipe 14 to the outside of the reactor body 5, and as a result, removed from the indium compound-containing solution. In this case, in the present embodiment, since the metal (Fe) used for removing the impurity metal is in the form of particles, for example, compared with a case where an iron lump or the like is input, The surface area of the metal (Fe) for causing the cementation reaction is increased, and the speed of the Sn precipitation reaction is improved. And some growth After the deposition of the observed metal is observed, the forced separation by ultrasonic vibration as described above always exposes a new metal surface (the surface of Fe particles) and maintains the reaction rate.

[0042] In addition, since the Fe metal particles flow in the reactor body 5 and Fe ²⁺ is eluted by the above-described cementation reaction, the metal particles charged into the upper chamber 13 are initially charged. The particle size in inevitably decreases with time. As a result, the waste liquid normally rises in the reactor main body 5 at the same upward flow speed, so that the metal particles that have become smaller and smaller in size as the force is applied to the upper part are larger. There is a risk of inadvertent overflow.

[0043] However, in this embodiment, the cross-sectional area of the reactor body 5 is formed so as to increase discontinuously with upward force in the present embodiment. The counter-flow velocity gradually decreases, so that the metal particles whose particle size has decreased due to the cementation reaction as described above will inadvertently overflow at the top of the reactor body 5 where the cross-sectional area increases. The possibility of being held in the reactor body 5 without increasing becomes high.

[0044] Further, when the indium compound-containing solution flows into the lower side force of the reactor main body 5 and passes through the reactor main body 5, a target metal such as Sn is deposited on the metal particles made of Fe by a cementation reaction. Therefore, the concentration of the impurity metal in the indium compound-containing solution decreases as the force toward the top of the reactor body 5 increases.

However, in the present embodiment, finer metal particles exist in the upper part of the reactor body 5 and the upward flow velocity of the indium compound-containing solution gradually decreases, so that the number of metal particles is increased. It is recognized that the total surface area of the metal particles increases toward the top of the reactor body 5. As a result, the reaction rate of the cementation reaction (impurity metal impurity extraction efficiency) is improved, so that the impurity metals Ni and Sn are also added to the upper part of the reactor body 5 where the impurity metal concentration is lower. It is possible to remove the waste liquid efficiently.

Next, the indium compound-containing solution from which Sn has been removed is supplied to the precipitation removing device 3.

An alkali (alkaline solution) such as sodium hydroxide is added to the precipitation removing device 3. This results in Fe hydroxide and indium hydroxide solids. That is, in the reactor 2 for removing impurities, Sn is precipitated and removed from Fe particles by the cementation reaction, while Fe ions (Fe ²⁺ ) are eluted in the indium compound-containing solution. Therefore, the Fe ²⁺ is also before recovery reactor 4 Heinjiu beam compound-containing solution in the subsequent stage is supplied, it is necessary to remove from the pre-indium compound-containing solution. Therefore, the addition of an alkali as described above will produce a solid product of Fe hydroxide and indium hydroxide. Fe hydroxide has an overwhelmingly faster precipitate formation rate than indium hydroxide. By controlling the residence time of the liquid to be treated in the precipitation removing device 3 such as a precipitation tank, the Fe hydroxide is easily removed by the precipitation removing device 3.

[0047] Next, the indium compound-containing solution after precipitation and removal of Fe hydroxide is adjusted to pHl. 5 or lower and indium hydroxide is redissolved, and then supplied to the recovery reactor 4. The indium compound-containing solution supplied to the recovery reactor 4 flows into the reactor body 5 from the inflow pipe 12 through the inflow chamber 11 as in the case of the impurity removal reactor 2. On the other hand, metal particles (Zn particles or A1 particles) for causing a cementation reaction are introduced from the upper chamber 13. As in the case of the impurity removing reactor 2, in the reactor body 5, the indium compound-containing solution that has flowed in rises and the metal particles introduced from the upper chamber 13 become a fluid state.

[0048] Then, a so-called cementation reaction is caused based on the difference in ionization tendency between In in the indium compound-containing solution to be collected and Zn or A1 as the charged metal particles. The reduction reaction of each metal ion is as follows, and the standard electrode potential (E °) of each metal ion is indicated for each.

[0049] In ³⁺ + 3e → In--(3) 0. 34V

Zn ²⁺ + 2e → Zn · '· (4) —0. 76V

Al ³⁺ + 3e → Al--(5) —1.66V

[0050] As apparent from the above (3) to (5), the standard electrode potential force S of Zn ²⁺ or Al ³⁺ is smaller than that of In ³⁺ . In other words, the ionization tendency of Zn or A1 is larger than that of In. Therefore, Zn or A1 with a large ionization tendency becomes Zn ²⁺ or Al ³⁺ (reaction opposite to the above formulas (4) and (5)) in the fluidized state as described above. solution In ³⁺ is dissolved in and contained in the indium compound-containing solution, and In ³⁺ becomes In and precipitates on the surface of Zn or A1 particles.

[0051] After causing In to be deposited on the surface of the Zn or A1 particles by such a cementation reaction, the ultrasonic oscillators 15a, 15b, and 15c are operated. By operating the ultrasonic oscillators 15a, 15b, and 15c, the ultrasonic waves oscillated from the ultrasonic oscillators 15a, 15b, and 15c are vibrated and stirred on the Zn or A1 particles on which the In is precipitated. A force is applied, so that the precipitated In is forcibly separated from the Zn or A1 particles.

[0052] The In peeled in this way is discharged from the upper chamber 13 through the discharge pipe 14 to the outside of the reactor main body 5, whereby In is recovered as a valuable metal. In this case, in this embodiment, since the particulate Zn is used as Zn or A1 in the same manner as in the case of iron in the impurity removal reactor 2, a metal for causing a cementation reaction is used. The surface area increases and the rate of In precipitation reaction increases.

Then, after the deposition of some grown metal is observed, the surface of new Zn or A1 particles can always be exposed and the reaction rate can be maintained by forced peeling by ultrasonic vibration as described above. .

[0053] In addition, since Zn ²⁺ or Al ³⁺ is also eluted by the cementation reaction, the particle size of Zn or A1 introduced into the upper chamber 13 is as follows. It will inevitably decrease over time. As a result, the indium compound-containing solution normally moves up in the reactor main body 5 at almost the same upward flow rate, so that the particle size decreases and becomes smaller toward the upper part. Particles may inadvertently overflow from the reactor body 5.

However, in this embodiment, since the cross-sectional area of the reactor body 5 is formed so as to increase discontinuously as the upward force is increased in this embodiment, the indium compound is contained in the reactor body 5. The upward flow velocity of the solution gradually decreases. Therefore, the metal particles whose particle size has been reduced by the cementation reaction or the like as described above are not suitable for the upper part of the reactor body 5 where the cross-sectional area increases. The possibility of being held in the reactor body 5 without overflowing is increased. [0055] Further, the indium compound-containing solution also flows in the lower side force of the reactor main body 5, and when passing through the reactor main body 5, the target In is deposited on Zn or A1 particles by a cementation reaction. Therefore, the concentration of In in the indium compound-containing solution decreases as the force toward the top of the reactor body 5 increases.

However, in the present embodiment, finer Zn or A1 particles are present in the upper part of the reactor body 5 and the upward flow rate of the indium compound-containing solution gradually decreases. Alternatively, since it is recognized that the number of A1 particles increases, the total surface area of Zn or A1 particles increases toward the top of the reactor body 5. As a result, the reaction speed of the cementation reaction (In precipitation efficiency) is improved, so that the recovery target In is contained in the indium compound even in the upper part of the reactor body 5 where the In concentration is lower. This makes it possible to efficiently recover from the solution.

[Embodiment 2]

The present embodiment is different from the first embodiment in the structure of the reactor main body 5 of the impurity removing reactor 2 and the recovery reactor 4. That is, in the present embodiment, as shown in FIG. 3, the entire peripheral surface of the reactor body 5 is formed to be tapered upward, so that the cross-sectional area of the reactor body 5 continuously increases upward. It is configured. This is different from the case of the first embodiment in which the cross-sectional area of the reactor body 5 discontinuously increases upward.

Since the cross-sectional area that is not discontinuous is configured to continuously increase upward, the reactor upper part 6, the reactor middle part 7, and the reactor lower part 8 as in Example 1 in this embodiment. If it is divided and organized like

However, the ultrasonic oscillators 15a, 15b, 15c are provided in three places from the upper part to the lower part of the reactor main body 5 in common with the first embodiment. Therefore, in the present embodiment, as in the first embodiment, Sn which is an impurity metal to be removed, which is deposited on the metal particles by the ultrasonic waves oscillated from the ultrasonic oscillators 15a, 15b, 15c. Alternatively, it is possible to forcibly peel In, which is the metal to be collected.

[0059] In addition, although there is a difference between discontinuous and force continuous, the cross-sectional area is configured to increase upward, and in common with Embodiment 1, So this implementation Even in the form, a fine metal particle having a reduced particle size is retained at the upper part of the reactor body 5 to prevent inadvertent overflow and a reactor with a low concentration of the target metal. The effect is that the target metal can be efficiently removed or recovered at the upper part of the main body 5.

[0060] (Embodiment 3)

In this embodiment, as means for peeling the deposited metal from the metal particles, instead of the means for vibrating with ultrasonic waves oscillated by the ultrasonic oscillators of Embodiments 1 and 2, a means for stirring using magnetite is used. Adopted. That is, in this embodiment, the slide board 17 having the electromagnet 16 as shown in FIG. 5 is connected to the guide rail 18 provided on the side of the reactor body 5 having a rectangular horizontal section as shown in FIG. It can be moved up and down. As shown in FIG. 5, the slide board 17 has a space portion 19 in the center, and is disposed so as to surround the reactor body 5 by inserting the reactor body 5 into the space portion 19. The metal particles used in the present embodiment are iron or the like that is a magnetic material.

[0061] Then, as indicated by arrows 20 in FIG. 4, by alternately moving up and down, the metal particles in the reactor main body 5 are stirred, and a large number of metal particles collide with each other. Metal particle force The deposited metal is forcibly separated. Metal Particle Force Precipitation Although the means for separating the metal is different, in this embodiment as well, the deposited metal is preferably peeled from the metal particle to suitably remove the impurity metal or recover In which is a valuable metal. it can.

[0062] (Embodiment 4)

In the present embodiment, a case will be described in which an In elution treatment with acid, a washing neutralization treatment, and a drying treatment are performed while the waste LCD is placed in a bag. As shown in FIG. 6, the apparatus for recovering indium from the waste LCD of this embodiment includes an elution treatment device 25, a washing neutralization treatment device 26, and a drying treatment 27. As shown in FIG. 7, the elution treatment apparatus 25 includes an elution treatment container 22 such as an FRP tank. The elution processing container 22 is formed to have a size capable of storing a waste LCD accommodated in a bag 21 made of a resin or cloth such as a flexible container bag. A perforated plate 23 and a perforated plate support 24 are provided below the elution processing container 22. The bag 21 is made of the perforated plate 2 Configured to be held on 3!

Then, the waste LCD crushed by a crusher or the like is circulated through the hydrochloric acid solution for In dissolution extraction while being contained in the bag 21, and the waste LCD force is also reduced when the hydrochloric acid solution passes through the waste LCD layer 28. In is dissolved and extracted. In other words, the waste LCD force is also dissolved in indium tin oxide using hydrochloric acid to obtain an indium compound-containing solution.

[0063] On the other hand, the waste LCD after the dissolution and extraction treatment is moved to the next cleaning neutralization treatment device 26 while being accommodated in the bag 21 as it is, and is accommodated in the cleaning neutralization treatment device 26. Wash neutralization treatment. The movement from the elution treatment device 25 to the washing neutralization treatment device 26 is performed using a hoist or the like. As with the In dissolution treatment, circulate with water during washing and with an alkaline solution during neutralization. In this case, the circulation process may be performed in a downward flow or an upward flow. The waste LCD that has been washed and neutralized is moved to the drying device 27 while being stored and held in the bag. For example, the drying processing device 27 can perform the drying processing by a drying method such as sun drying without using such a drying processing device 27. The waste LCD after the drying process is held in the bag 21 as it is, and transported to the tile factory, glass factory, etc. as recycled raw materials.

[0064] In this embodiment, the processing can be simplified by performing the consistent processing while the fine waste LCD crushed in the waste LCD crushing step is stored in the bag 21 as described above. In addition, since it is not necessary to handle the fine waste LCD pieces that have been accepted as waste LCD crushing process as powder, handling does not become difficult.

[0065] The bag 21 only needs to have a mesh (porosity) that does not allow the waste LCD to fall off, and a cloth is sufficient. The entire noggle is porous enough to allow the hydrochloric acid solution to pass through! /, Or the bottom of the nod 21 may be formed to be porous. In any case, by installing the bag 21 on the perforated plate 23 in the elution treatment container 22, the bag and the wall surface of the elution treatment container 22 are brought into close contact with the dead weight of the waste LCD in the nodule 21, so that hydrochloric acid Since the solution passes through the waste LCD layer and moves from the bottom of the bag 21 to the bottom of the elution container 22 through the porous plate 23, it is possible to dissolve and extract In from the waste LCD by circulation processing. Become. [0066] (Other Embodiments)

In the above embodiment, the case where Sn is removed as an impurity metal other than In contained in an indium compound-containing solution obtained by dissolving ITO using hydrochloric acid from waste LCD column is described. However, metals other than Sn can be removed. In that case, metal particles other than Fe can be added.

Further, in the embodiment, the case where In is precipitated on metal particles and the precipitated In is peeled off by metal particle force has been described. However, the present invention is not limited to In being a simple metal, but an alloy of In and other metals, that is, The present invention can also be applied to the case where an In alloy is deposited on metal particles and the deposited In alloy is separated from the metal particles.

[0067] In the above embodiment, hydrochloric acid is used as the acid for dissolving ITO as the waste LCD force. However, the type of this acid is not limited to hydrochloric acid. For example, sulfuric acid, nitric acid or the like may be used. It is also possible to use a mixed acid or the like.

[0068] Further, in the above embodiment, the force that provides the above-described preferable effect by providing the impurity removal reactor 2 as described above is provided in the present invention. This is not a requirement. Furthermore, in the above embodiment, the metal particles added to the force recovery reactor described in the case of collecting In by adding Zn or A1 particles are not limited to the Zn or A1 particles of the embodiment. In short, the ionization tendency is larger than In, metal is used!

[0069] In this embodiment, the particle size of the metal particles is about 3 mm, but the particle size of the metal particles is not limited to the embodiment, and is preferably 0.1 to 8 mm. If it is less than 1 mm, the cementation reaction is not always performed favorably, and the deposited metal peeled off from the metal particles cannot be easily recovered! / If exceeded, the number of metal particles that can be held in the reactor 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 valuable metals or impurity metals for recovery purposes may be reduced. This is because other metals may be deposited on the metal particles.

[0070] Furthermore, in Embodiments 1 and 2, since the cross-sectional area of the reactor main body 5 is formed so as to increase toward the top, the force with which the above preferable effect is obtained is as described above. The formation of the main body 5 is not an essential condition for the present invention. Further, the means for separating the deposited metal from the metal particles may be other means than the means using the ultrasonic wave in the first and second embodiments and the means using the electromagnet in the third embodiment. Example

[0071] The 1%, 3%, and 10% hydrochloric acid solutions were used, and the In dissolution extraction process for the In recovery process was performed in an apparatus as shown in FIG. In FIG. 8, 28 is the waste LCD layer described in FIG. 7, 29 is a tube pump, 30 is hydrochloric acid, 31 is a resin container, and 32 is a mesh tank. From analysis, the waste LCD contained 400 mgZkg of In. In the elution process, the waste LCD24kg is held in a cotton bag, and the bag is placed in a 100L resin container as shown in Fig. 8. It was put in a container 31, 14 L of hydrochloric acid was added, and circulation treatment was performed at room temperature using a tube pump 29. To prevent moisture from evaporating and the concentration and amount of hydrochloric acid from changing during the elution process, the lid of the 100L resin container is equipped with a gasket, and a tube pump with a lid that can seal between the 100L resin container and the lid 29 The insertion part and the extraction part used were sealed with a caulking agent.

[0072] The test results are shown in Table 1.

[0073] [Table 1]

[0074] As is clear from Table 1, in any treatment, a sufficient In recovery rate of 98% or more was obtained by the elution treatment for 24 hours. The recovery rate was calculated from the waste LCD weight and In content, the In concentration in hydrochloric acid after treatment, and the amount of hydrochloric acid.

Claims

The scope of the claims

[1] Crushing the waste liquid crystal display containing indium tin oxide, dissolving the crushed waste liquid crystal display with acid, and dissolving the indium tin oxide with an acid to obtain an indium compound-containing solution, which flows into the recovery reactor In addition, in the recovery reactor, metal particles having a larger ionic tendency than indium and metal power are added, the metal particles are fluidized, and indium or an indium alloy contained in the indium compound-containing solution is added. Precipitating on the surface of the metal particles, and then separating the indium or indium alloy deposited from the metal particles by a peeling means, and separating and recovering the separated solid indium or indium alloy from the liquid. A method for recovering indium from a waste liquid crystal display.

[2] The method for recovering indium from a waste liquid crystal display according to [1], wherein the metal particles having a metal force having a higher ionic tendency than indium are zinc particles or aluminum particles.

[3] The means for peeling off the indium or indium alloy deposited on the metal particles is a means for vibrating the metal particles by ultrasonic waves, or a means for stirring the metal particles with an electromagnet and causing them to collide with each other. Or a method for recovering indium from the waste liquid crystal display according to 2 above.

[4] Before the indium compound-containing solution in which indium tin oxide is dissolved, such as the waste liquid crystal display, flows into the recovery reactor, the indium compound-containing solution is allowed to flow into the impurity removal reactor to contain the indium compound. Metal particles made of a metal having an ionic tendency greater than that of an impurity metal other than indium in the solution are added to the impurity removal reactor to cause the metal particles to flow, and the impurity metal is deposited on the surface of the metal particles. 4. The method for recovering indium of waste liquid crystal display power according to claim 1, wherein the deposited impurity metal is peeled off and removed from the metal particles by a peeling means.

[5] The means for separating the impurity metal deposited on the metal particles from the metal particles is a means for vibrating the metal particles by ultrasonic waves, or a means for stirring the metal particles with an electromagnet and causing them to collide with each other. How to recover indium from waste liquid crystal displays Law.

6. The method for recovering indium from a waste liquid crystal display according to claim 4 or 5, wherein the impurity metal is tin.

[7] The method for recovering indium from a waste liquid crystal display according to any one of claims 4 to 6, wherein the metal particles having a higher ionic tendency than the impurity metal are iron particles.

[8] The method for recovering indium with waste liquid crystal display power according to [7], wherein an alkali is added to the indium compound-containing solution after removing the impurity metal, and iron is precipitated and removed as a hydroxide.

[9] A waste liquid crystal display containing indium tin oxide is crushed, and the crushed waste liquid crystal display is stored in a bag, and indium tin oxide is dissolved from the waste liquid crystal display using an acid to form an indium compound. A method for recovering indium from a waste liquid crystal display, wherein the waste liquid crystal display contained in the bag is washed and neutralized, and then dried.

[10] A crusher for crushing a waste liquid crystal display containing indium tin oxide, an indium dissolution apparatus for dissolving the indium tin oxide using an acid in the crushed waste liquid crystal display to obtain an indium compound-containing solution, The indium compound-containing solution obtained by the indium melting apparatus flows in, and metal particles made of a metal having a larger ionic tendency than the indium are added to deposit indium or an indium alloy on the surface of the metal particles. A recovery reactor for performing a metal precipitation reaction to be performed; a stripping means for stripping the deposited particle or indium alloy; and a stripping means for stripping the separated metal indium or indium alloy; From a waste liquid crystal display characterized by having a separating means for separating Recovery unit of indium.

[11] The apparatus for recovering indium from a waste liquid crystal display according to [10], wherein the metal particles having a higher ionic tendency than indium are zinc particles or aluminum particles.

12. The means for peeling off indium or an indium alloy deposited on metal particles is a means for vibrating metal particles by ultrasonic waves, or a means for stirring metal particles with an electromagnet and causing them to collide with each other. Or 11 waste liquid crystal display Indium recovery equipment.

[13] An indium compound-containing solution obtained by an indium melting apparatus is allowed to flow in, and an ionic valence tendency is larger than impurity metals other than indium in the indium compound-containing solution, and metal particles made of metal are added. An impurity removal reactor comprising means for flowing the metal particles, precipitating the impurity metals on the surfaces of the metal particles, and separating and removing the precipitated impurity metals from the metal particles is a recovery reactor. The apparatus for recovering indium from a waste liquid crystal display according to any one of claims 10 to 12, provided on the front side.

14. The means for separating the impurity metal deposited on the metal particles from the metal particles is a means for vibrating the metal particles by ultrasonic waves, or a means for stirring the metal particles with an electromagnet and causing them to collide with each other. A device for recovering indium from the described liquid crystal display.

15. The apparatus for recovering indium from a waste liquid crystal display according to claim 13 or 14, wherein the impurity metal is tin.

[16] The apparatus for recovering indium from a waste liquid crystal display according to any one of claims 13 to 15, wherein the metal particles having a higher ionic tendency than the impurity metal and having a metallic force are iron particles.

[17] The apparatus for removing indium from a waste liquid crystal display according to claim 16, further comprising a precipitation removing device for adding an alkali to the indium-containing solution after removing the impurity metal to precipitate and remove iron as a hydroxide. Recovery device.