WO2012011770A2 - Selective recovery method for rare metals - Google Patents

Abstract

(Problem) Provided is a recovery method for rare metals of a novel kind, which allows a specific metal component to be recovered with good selectivity from among rare metals, and which imposes little stress on the environment. (Means of resolution) A selective recovery method for rare metals which comprises the following process (1) and process (2): (1) a process wherein a metal component comprising a rare metal is adsorbed or stored in solid phase by means of a method in which an aqueous solution that contains the metal component comprising the rare metal is brought into contact with a chelating resin or an adsorption agent, or a method in which a precipitate of a metal compound is formed in an aqueous solution containing the metal component comprising the rare metal, and (2) a process wherein the solid phase resulting from the adsorption or storage of the metal component comprising the rare metal, obtained in process (1), is brought into contact with an aqueous solution containing a peroxy compound.

Description

Selective recovery method of rare metal

TECHNICAL FIELD This invention relates to the selective collection method of the rare metal component which consists of molybdenum, tungsten, and vanadium.

In recent years, deeply related to the development of advanced science and technology, a high-performance material is a non-ferrous metal called rare metal, and has attracted wide attention in the field of materials and catalyst chemistry.

Of these rare metals, molybdenum is an important metal widely used in the manufacture of special steels, lubricants, spark plugs, electronic materials, color pigments, filaments such as fluorescent lamps, etc., but it is an item that requires monitoring for which water is regulated.

Vanadium, on the other hand, is a desulfurization catalyst; clothing material; Additives for titanium, aluminum, zirconium, steel and the like; Heat-resistant materials such as jets and guided missiles; Sputtering target; Materials for vacuum tube deposition; Alloy superconducting materials; It is used for various uses, such as a hydrogen storage alloy. Moreover, tungsten is used abundantly for uses, such as a cemented carbide and a catalyst.

With the recent technological innovation and the development of emerging countries such as China and India, the usage of rare metals such as precious metals is increasing rapidly, and the efficiency of metal recovery is urgently needed from the viewpoint of securing resources.

As a recovery method of these metals, it is a solid state treatment method made to adsorb | suck using a chelate resin, an ion exchange resin, etc .; A treatment method by concentric treatment using iron, aluminum, or the like; Methods of concentration treatment with activated carbon and the like have been studied (see Non-Patent Documents 1 and 2 below). This treatment method is advantageous in view of having a high adsorption capacity for a large number of metal ions (variability of the metal to be recovered) and being able to repeatedly use a solid phase (regeneration treatment potential, low cost, and low environmental load).

As a method of separating the metal adsorbed or occluded in the solid phase or precipitation by the above-mentioned method, strong acid (nitric acid, hydrochloric acid, sulfuric acid) is generally used. This is achieved by exchanging cations of metals with protons in strong acids, elution of surface-adsorbed metal salts, dissolution by precipitation acids, and the like. However, as a demerit of using strong acids, it is expensive to construct treatment systems with acid resistance specifications. Moreover, the thing with low selectivity of the metal to elute is mentioned. In addition, although nitric acid is a very good solvent for dissolving metal ions, nitrogen is regulated by the law for the prevention of eutrophication. In addition, hydrogen sulfide and ammonia are used to recover heavy metals and form precipitates, but they have problems such as odor.

(Prior art document)

Non-Patent Document 1: Bulletin of Chemical Society of Japan, 74 (1), 31-38 (2001).

[Non-Patent Document 2] Modern Methods for Trace Element Determination, John Wiley and Sons Ltd (1993).

This invention is made | formed in view of the phenomenon of the prior art mentioned above, The main objective is the collection | recovery of the new rare metal which can collect | recover a specific metal component selectively among rare metals, and also has little load on the environment. To provide a way.

MEANS TO SOLVE THE PROBLEM This inventor has earnestly researched in order to achieve the objective mentioned above. As a result, a method in which an aqueous solution containing a metal component containing a rare metal is contacted with a chelating resin or an adsorbent to adsorb the metal component, or a precipitate is formed in an aqueous solution containing a metal component including a rare metal, and the metal component is subjected to precipitation. According to the method of adsorbing or occluding, the metal component containing a rare metal is adsorbed or occluded in a solid phase, and then the solid phase is contacted with an aqueous solution containing peroxy compounds such as sodium percarbonate, hydrogen peroxide, and ozone. Among the metal components adsorbed or occluded, it was found that specific rare metal components such as molybdenum, vanadium and tungsten can be eluted with good selectivity. This method is inexpensive, easy to handle, and has a high economic efficiency in that a specific rare metal can be recovered selectively using a peroxy compound having a low environmental load, which is advantageous for high purity of the rare metal. found. In addition, since the recovery liquid containing the rare metal component contains almost no nitrogen, other heavy metals, etc., it is possible to cope with the regulation of the total amount of nitrogen in the wastewater, and the chelating resin and the adsorbent after the recovery can be reused. Found out how. This invention is completed based on this knowledge.

That is, this invention provides the selective recovery method of the following rare metals.

Item 1. A selective recovery method of a rare metal, comprising the following steps (1) and (2):

(1) Rare metal by a method of contacting an aqueous solution containing a metal component containing a rare metal with a chelating resin or an adsorbent, or by forming a precipitate of a metal compound in an aqueous solution containing a metal component containing a rare metal. Adsorbing or occluding a metal component including a solid; (2) The process of making the solid which adsorb | sucked or occluded the metal component containing a rare metal obtained in the said process (1) contacting the aqueous solution containing a peroxy compound.

Item 2. The selective recovery method of the rare metal according to the item 1, wherein the chelate resin used in the step (1) is a resin containing an imino diacetic acid group or a salt thereof.

Item 3. The precipitate formed in step (1) is a precipitate containing at least one component selected from the group consisting of aluminum hydroxide, magnesium hydroxide, gallium hydroxide, iron hydroxide, manganese hydroxide, manganese oxide, indium hydroxide, and a rare earth element hydroxide. The selective recovery method of the rare metal according to the above item 1 or 2.

Item 4. The selective recovery method for rare metal according to any one of items 1 to 3, wherein the peroxy compound used in step (2) is at least one component selected from the group consisting of sodium percarbonate, hydrogen peroxide, and ozone.

Item 5. The rare metal, including the step of selectively recovering the rare metal by the method according to any one of items 1 to 4 above, followed by washing the used chelating resin or the adsorbent with an acid aqueous solution and reusing it in step (1). Selective recovery method.

The selective recovery method of the rare metal of the present invention comprises (i) a method of adsorbing a metal component by contacting an aqueous solution containing a metal component including the rare metal with a chelating resin or an adsorbent, or an aqueous solution containing a metal component including the rare metal. A first step of adsorbing or occluding a metal component including a rare metal in a solid phase by a method of forming a precipitate in the precipitate and adsorbing or occluding a metal component in the formed precipitate, and (ii) a solid phase that adsorbs or occludes the metal component. It is a method which consists of a 2nd process which contacts a aqueous solution containing a peroxy compound, and elutes a specific rare metal. Hereinafter, the method of this invention is demonstrated concretely.

(1) First process:

(i) Amount to be processed

In the selective recovery method of the rare metal of the present invention, the treatment target is an aqueous solution containing at least one rare metal component selected from the group consisting of molybdenum, vanadium and tungsten. Although there is no limitation in particular about the kind of liquid to process, For example, the aqueous solution which extracted the metal component contained in the incineration fly ash collected by the waste incinerator using nitric acid, etc., the dilution of sewage sludge, etc. are processed. You can do In such incineration fly ash and sewage sludge, there have been reports that molybdenum, tungsten, etc. are highly concentrated (analytical chemistry: 57, 659-666 (2008)), and environmental pollution is concerned, but according to the method of the present invention, The causative component can be separated and recovered for effective use.

The amount of molybdenum, vanadium, and tungsten in the liquid to be treated is not particularly limited. For example, even when a low concentration aqueous solution of about 1 ppm is used as a treatment target, the amount of emission limitation (Environmental Protection Act for Human Health) Environmental standard about molybdenum: It can be reduced to concentration below 0.07mg / L). On the other hand, even for a high concentration aqueous solution having a concentration of such a rare metal component of about 1 g / L, the rare metal is recovered at a high recovery rate by appropriately selecting the type and amount of the chelating resin or the adsorbent to be used, the amount of precipitation formed, and the like. It is possible.

In addition to the rare metal component which consists of molybdenum, vanadium, and tungsten mentioned above, various metal components may coexist in the process liquid. For example, in addition to molybdenum, vanadium and tungsten, aluminum, iron, manganese, copper, zinc, nickel, cobalt, cadmium, tin, gallium, lead, rare earth elements and the like may be contained.

According to the method of the present invention, a peroxy compound is used in the second step after performing an adsorption treatment to a solid phase such as a chelating resin, an adsorbent, or a precipitation in the first step by using an aqueous solution containing such various metal components as the treatment target liquid. By carrying out the elution treatment using a treatment liquid containing, specific rare metal components such as molybdenum, vanadium and tungsten can be eluted with good selectivity.

(ii) adsorption treatment with chelate resin or adsorbent:

First, the method of making a metal component adsorb | suck to a chelate resin or an adsorbent in the 1st process of this invention is demonstrated.

(a) chelate resin

It does not specifically limit about the kind of chelate resin, What is necessary is just resin which has a functional group which has chelate formation ability with respect to various metal components.

As a specific example of the functional group which has chelate formation ability, group containing at least 2 sort (s) of atom chosen from the group which consists of an oxygen atom, a nitrogen atom, a sulfur atom, and a phosphorus atom is mentioned, for example. As an example of the functional group which has such a chelate formation ability, an imino diacetic acid group, an imino diphosphate group, an aminocarboxylic acid group, an aminophosphate group, a glucamine group, a thiol group, a sulfide group, these salts, etc. are mentioned. Among these, an imino diacetic acid group, an imino diphosphate group, an aminocarboxylic acid group, an amino phosphate group, these salts, etc. are preferable, and an imino diacetic acid group and its salt are especially preferable. As a salt of each group mentioned above, Alkali metal salts, such as a sodium salt and potassium salt; Alkaline earth metal salts such as magnesium salts and calcium salts; Ammonium salts, such as a trimethylammonium salt, a triethylammonium salt, ethanol ammonium salt, and diethanol ammonium salt, etc. are mentioned.

There is no restriction | limiting in particular also about the kind of resin skeleton of the chelate resin containing the functional group which has the chelate formation ability mentioned above, For example, chelate resin which has various resin skeletons, such as styrene type, a phenol type, an acryl type, an epoxy type, can be used. have.

Although there is no limitation in particular also about the shape of a chelate resin, It is preferable to use the thing of the shape with favorable contact with a process liquid. For example, powdered resin, film | membrane resin, fibrous resin, etc., what was shape | molded in the filter form, etc. can be used.

The ion exchange capacity of the chelate resin is not particularly limited, but for example, one having an exchange capacity of about 0.1-5.0 meq cm ^-3 can be used.

(b) adsorbent

The kind of the adsorbent is not particularly limited, but may be any adsorbent having adsorption capacity to various metal components including rare metals. As for the adsorbent used in this method, selective adsorption capacity for a specific component is not required, and one having an adsorption capacity for various metal components can be used.

As a specific example of an adsorbent, Carbon powder, such as activated carbon; iron content; Various ceramics (alumina, zirconia, ceria, etc.); Porous polymers; Wood adsorbents; Fibers and the like.

The adsorbent mentioned above can be used individually by 1 type or in mixture of 2 or more types. The adsorption mechanism of the metal component to the adsorbent is considered to be surface adsorption, occlusion, mixed crystals, formation of complexes, etc., and is considered to be introduced into the adsorbent as a combination thereof.

(c) adsorption treatment method

The method for adsorbing an aqueous solution containing at least one metal component selected from the group consisting of molybdenum, vanadium and tungsten, which is the liquid to be treated, is not particularly limited, and the liquid to be treated and the chelate resin or the adsorbent are not particularly limited. What is necessary is just the method which can fully contact.

Usually, what is necessary is just to make a process liquid flow through the column using the adsorption column packed with the chelate resin or adsorbent of suitable particle size. What is necessary is just to determine about the liquid passing conditions of the specific metal containing solution in this case so that the target metal component may fully be adsorbed according to the quantity of the metal component contained in a process liquid.

Moreover, after disperse | distributing a chelating resin or adsorbent in a process liquid, and fully mixing, you may isolate | separate a chelating resin or adsorbent by methods, such as filtration and centrifugation. The amount of the chelate resin and the adsorbent in this case is not particularly limited either, and the amount of the chelate resin or the adsorbent capable of adsorbing a sufficient amount of the metal component is dispersed according to the amount of the metal component contained in the treatment liquid. Just do it.

Usually, what is necessary is just to determine suitably the usage-amount of a chelate resin and an adsorbent according to the quantity of the rare metal contained in a process liquid, and, for example, chelate, when it flows through the column which filled a chelate resin or an adsorbent, What is necessary is just to use so that the weight ratio (liquid amount / chelate or adsorbent) of the liquid flow amount of a process liquid with respect to the weight of resin or an adsorbent will be about 1-1000.

Moreover, as a weight ratio (rare metal / chelate resin or adsorbent) of a rare metal with respect to a chelate or an adsorbent, it is good to set it as the range about 0.000001 to 1 time normally.

With respect to the liquid temperature at the time of treatment, when the temperature is low, the adsorption rate is slowed. On the contrary, when the temperature is too high, a special device is required, such as making the adsorption column heat resistant. For this reason, what is necessary is usually just to make the liquid temperature of a process target liquid about 20-50 degreeC, and it is preferable to set it as about 25-30 degreeC.

(iii) adsorption or occlusion treatment for precipitation:

Next, the method of making a metal component adsorb | suck or occlude for precipitation of a metal compound in 1st process of this invention is described concretely.

(a) precipitation component

There is no restriction | limiting in particular about the kind of metal compound which forms a precipitation, The compound used as a raw material is soluble in the aqueous solution containing the rare metal to be processed, and can form a poorly soluble or insoluble metal compound in the aqueous solution. You just need to be. In particular, it is preferable that the specific surface area of the precipitate formed is large, and a precipitation phenomenon arises quickly.

Examples of such precipitation include poorly soluble hydroxides, poorly soluble phosphates, sulfides, and oxides. Among these, specific examples of poorly soluble hydroxides include aluminum hydroxide, magnesium hydroxide, gallium hydroxide, iron hydroxide, manganese hydroxide, zirconium hydroxide, indium hydroxide, yttrium hydroxide, titanium hydroxide, bismuth hydroxide, thorium hydroxide, and hydroxides of rare earth elements. Can be. Examples of the poorly soluble phosphate include aluminum phosphate, calcium phosphate, zirconium phosphate, lead phosphate, bismuth phosphate, and phosphates of rare earth elements. Examples of sulfides include copper sulfide, cadmium sulfide, indium sulfide, barium sulfide, mercury sulfide, lead sulfide and the like. Manganese oxide etc. can be illustrated as an oxide.

Among them, aluminum hydroxide, magnesium hydroxide, gallium hydroxide, iron hydroxide, manganese hydroxide, manganese oxide, indium hydroxide, rare earth elements and the like are preferred from the viewpoints of ease of precipitation recovery, metal adsorption capacity, and economy of the precipitant.

The metal compound which forms the above-mentioned precipitation may be one type, or may be a combination of 2 or more types.

(b) precipitation formation method

The method for forming a precipitate in an aqueous solution containing at least one metal component selected from the group consisting of molybdenum, vanadium and tungsten to be treated is not particularly limited, but for example, precipitation in a treatment target liquid containing rare metal A precipitate can be formed by dissolving a soluble compound (e.g., nitrate, chloride, sulfate, etc.), which is a raw material for forming a precipitate, and adding a component (precipitant) necessary to form a precipitate in the liquid. have. In this case, the kind of precipitant may be determined depending on the kind of precipitation to be formed. For example, in the case of forming a precipitate of poorly soluble hydroxide, depending on the kind of the metal compound forming the precipitate, it is necessary to have a required pH value. Precipitation of hydroxide can be formed by adding an alkali component. In the case of forming poorly soluble phosphate, precipitation of poorly soluble phosphate can be formed by reaction with a metal component contained in the liquid by adding soluble phosphate.

The addition amount of the compound serving as a raw material for forming the precipitate is not particularly limited, but may be appropriately determined depending on the amount of the rare metal contained in the liquid to be treated. Usually, it is preferable to add the raw material for precipitation formation of the quantity of about 10 to 1000 weight times of the quantity of the rare metal to collect, and to add the raw material for precipitation formation about 100 to 1000 weight times. More preferred.

Although there is no restriction | limiting in particular also about the temperature at the time of precipitation formation, Usually, what is necessary is just to set it as liquid temperature of about 25-50 degreeC, and it is preferable to set it as about 25-30 degreeC.

By forming a precipitate by the above-mentioned method, it is thought that the metal component containing the rare metal contained in the process liquid is introduce | transduced in the precipitation formed as surface adsorption, occlusion, and mixed crystal combination.

The precipitate formed can be separated and recovered from the liquid to be treated by filtration, centrifugation, decantation, flotation, or the like.

(2) second process

In the second step of the method of the present invention, in the first step, a solid phase obtained by adsorbing or occluding a metal component including a rare metal, that is, a chelating resin, an adsorbent or a precipitate, is brought into contact with an aqueous solution containing a peroxy compound to provide molybdenum It is a process of selectively eluting the rare metal component which consists of vanadium and tungsten.

(i) peroxy compounds

In this invention, it is preferable to use at least 1 sort (s) of component especially chosen from the group which consists of sodium percarbonate, hydrogen peroxide, and ozone as a peroxy compound. By using an aqueous solution containing such a peroxy compound, the elution treatment is carried out by a method described below, whereby a rare layer composed of molybdenum, vanadium and tungsten is obtained from a chelate resin, an adsorbent, or a precipitate adsorbed or occluded a metal component in the first step. The metal component can be eluted with high selectivity.

These peroxy compounds are inexpensive and easy to handle and contain hydrogen, oxygen, and carbon as constituent elements, and do not contain eutrophic and malodorous elements such as nitrogen and sulfur. Less material. In particular, sodium percarbonate is a compound which is not subject to regulation such as a mineral, is a reagent outside the regulation subject to handling amount, and is a solid, and is a compound that is easy to handle. As for ozone, it is advantageous in that it is highly reactive with peroxy compound formation and is a gas generated from water and ultraviolet rays, which can be freely generated in the reaction vessel, but does not remain because it is rapidly decomposed after the reaction. Compound.

In the aqueous solution containing the peroxy compound used as the eluate, the concentration of the peroxy compound is not particularly limited, but for example, molybdenum, vanadium and tungsten may be selectively selected in a wide concentration range such as about 0.1 to 40% by weight. It can collect | recover and it is preferable to use especially in concentration of about 1-30 weight%.

(ii) Dissolution treatment method

The method for selectively recovering molybdenum, vanadium and tungsten from the solid phase obtained by adsorbing or occluding the metal component, that is, the chelate resin, the adsorbent, or the precipitation obtained in the first step is not particularly limited, What is necessary is just the method which can fully contact the aqueous solution containing an oxy compound. For example, the method of disperse | distributing a chelating resin, an adsorbent, or precipitation to the aqueous solution containing a peroxy compound, the method of passing through the aqueous solution containing a peroxy compound to the column filled with the chelate resin or an adsorbent, etc. are mentioned. .

The liquid temperature at the time of the elution treatment is not particularly limited, and treatment can be performed at a temperature range of about 90 ° C. from room temperature.

The amount of the aqueous solution containing the peroxy compound is not particularly limited, but the amount of the aqueous solution that can sufficiently elute the rare metal, depending on the amount of the rare metal and other metals adsorbed or occluded in the chelate resin, the adsorbent or the precipitation. You can use For example, 1 g of an aqueous solution containing 0.1-40% by weight of a peroxy compound is passed through 1-50 ml of the solid phase consisting of a chelate resin, an adsorbent, or a precipitation, or about 1 g of the solid phase is added to the aqueous solution of this range. It may be stirred.

About the processing time, a sufficient amount of the rare metal can usually be eluted in a relatively short time of about 1 to 10 minutes.

According to the method mentioned above, the rare metal component which consists of molybdenum, vanadium, and tungsten can be eluted with high selectivity from the solid phase which adsorbed or occluded the metal component containing a rare metal. Although it is not clear why this specific rare metal can be eluted with good selectivity, molybdenum, vanadium, and tungsten are all dominated by ionic species (III to VI), which are highly oxidized, belong to oxo acid-based metal elements, and It is assumed that the present form is different from the metal ion, reacts with the peroxy compound to form a felxo complex or heteropoly acid, and elutes with good selectivity.

The eluate obtained by eluting the rare metal component composed of molybdenum, vanadium and tungsten by the above-described method is capable of recovering the rare metal component according to conventional methods such as evaporation method, reprecipitation method and various solid phase methods (activated carbon, various adsorbents). Can be. Since the content of the metal component other than the rare metal component mentioned above is very small, the eluate can collect | recover the high purity rare metal component efficiently.

In particular, in the first step, when the metal component is adsorbed using the chelate resin, the alkali metal component other than the heavy metal component bonded to the functional group of the chelate resin is cleaned by sufficiently washing the chelate resin after the adsorption treatment. It can be easily removed. For this reason, an alkali metal component etc. are hardly contained in the eluate after the process by a peroxy compound, and the high purity rare metal component can be obtained easily.

(3) regeneration treatment process

After performing the elution process with a peroxy compound by the method mentioned above, about the chelating resin and adsorbent after a process are isolate | separated from the eluate by methods, such as filtration and centrifugation, and it wash | cleans enough, and after that, By performing the separation removal process of a metal component, it is possible to reuse in the processing method of this invention.

The kind of acid used for separating and removing the metal component from the chelate resin and the adsorbent is not particularly limited, and for example, hydrochloric acid, sulfuric acid, nitric acid, and the like can be used. There is no restriction | limiting in particular also about an acid concentration, For example, the aqueous solution of the acid of the density | concentration of about 0.1-6 mol / L can be used. In particular, when nitric acid is used, soluble salts can be formed with respect to many metal components adsorbed on the chelate resin and the adsorbent, so that the regeneration treatment of the chelate resin and the adsorbent can be performed efficiently.

There is no restriction | limiting in particular about the method of the regeneration process of a chelating resin and an adsorbent, For example, after adding a chelating resin or an adsorbent to be treated to the aqueous solution of an acid, stirring it sufficiently, a chelating resin or an adsorbent is isolate | separated by methods, such as filtration. The method of carrying out, the method of flowing an aqueous solution of an acid, etc. can be applied to the column which filled the chelating resin or the adsorbent.

The chelate resin and the adsorbent subjected to the regeneration treatment with an acid by the above-described method, in the first step of the method of the present invention, from the aqueous solution containing at least one metal component selected from the group consisting of molybdenum, vanadium and tungsten, It can be reused in the process of adsorbing a component.

According to the selective collection method of the rare metal of this invention, the remarkable effect shown below is exhibited.

(1) According to the present invention, specific rare metals such as molybdenum, vanadium, and tungsten can be selectively separated and recovered from an aqueous solution in which various kinds of metal ions coexist in addition to the rare metal. For this reason, according to the method of this invention, the efficient collection | recovery of a rare metal is attained, and the cost reduction in the refinement | purification process after collection | recovery can be aimed at. The method of the present invention is also advantageous for the high purity of the rare metal.

(2) The peroxy compound which is an active ingredient in the eluate is an inexpensive and easy-to-handle substance, and since acid-resistant devices are unnecessary, the cost can be reduced.

In addition, the peroxy compound contains hydrogen, oxygen, and carbon as constituent elements, and does not contain eutrophic and malodorous elements such as nitrogen and sulfur.

In particular, sodium percarbonate is a reagent outside the regulation subject to the handling amount and the like, and is a compound that is easy to handle because it is a solid. In addition, ozone is a gas that is highly reactive with peroxy compound formation and is a gas generated from water and ultraviolet rays, and is advantageous in that it does not remain because it can be freely generated in the reaction vessel, but is rapidly decomposed after the reaction. Compound.

(3) Since the recovery liquid containing the rare metal component contains almost no nitrogen or other heavy metals, it is possible to cope with the regulation of the total amount of nitrogen in the wastewater, and the chelating resin and the adsorbent after the recovery can be reused. It is an advantageous way.

BRIEF DESCRIPTION OF THE DRAWINGS It is a graph which shows the relationship between the pH of the process liquid at the time of adsorption to the chelate resin obtained in Example 1, and the recovery rate of a metal component.

FIG. 2 is a graph showing the relationship between the temperature of hydrogen peroxide water and the recovery rate of metal components in the elution treatment obtained in Example 1. FIG.

3 is a graph showing the relationship between the concentration of hydrogen peroxide water and the recovery rate of metal components in the elution treatment obtained in Example 1. FIG.

4 is a graph showing the recovery rate of metal components in the hydrogen peroxide elution treatment obtained in Example 1. FIG.

5 is a graph showing a recovery rate of a metal component during nitric acid elution treatment obtained in Example 1. FIG.

6 is a graph showing a recovery rate of a metal component during hydrochloric acid elution treatment obtained in Example 1. FIG.

7 is a graph showing a recovery rate of a metal component in the sulfuric acid leaching treatment obtained in Example 1. FIG.

FIG. 8 is a graph showing the recovery of each metal when using 30 wt% hydrogen peroxide solution obtained in Example 4. FIG.

9 is a graph showing the recovery of each metal when using 1% by weight hydrogen peroxide solution obtained in Example 4. FIG.

Hereinafter, an Example is given and this invention is demonstrated in detail.

<Example 1>

Ammonium molybdate ((NH ₄ ) ₆ Mo ₇ O ₂₄ 4H ₂ O), ammonium vanadate (NH ₄ VO ₃ ), and ammonium tungstate pentahydrate (5 (NH ₄ ) ₂ · 12 WO ₃ · 5H ₂ O ), A metal mixed solution in which water was dissolved in water at a concentration of 10 mg / kg, respectively. The ultrapure water refine | purified by the Milli-Q system (Milli-Q SPTOC) made from Millipore was used for preparation of the metal mixture solution. The same applies to water used below.

First, 1 mL of the metal mixture solution mentioned above was added to the centrifuge tube, and pH was adjusted with the buffer solution. Subsequently, in this metal mixture, a weakly acidic cation exchange resin (trade name: Muromac B-1, manufactured by Muromachi Technos Co., Ltd.), having a sodium imino diacetate group, as a chelating resin, has a matrix structure: styrene-divinylbenzene air. 0.3 g of coalescing, total exchange capacity: 2.4 eq / L, water content of 50-55%, particle size distribution: 0.3-1.25 mm) was added, and it stirred with the magnetic stirrer for 2 hours. Thereafter, centrifugation was performed at 3500 rpm for 12 minutes, and the supernatant solution was subjected to ICP mass spectrometry (ICP-MS) and ICP emission spectrometry (ICP-AES) to calculate the residual and adsorption rates of the metal components.

Subsequently, 10 mL of hydrogen peroxide water (concentration 30% by weight) at room temperature was added to the chelated resin after centrifugation, and allowed to stand for 2 minutes, after which hydrogen peroxide water was recovered and the metal adsorbed to the chelate resin was eluted.

Next, ICP-MS measurement and ICP-AES measurement were performed about the eluate, and the recovery rate of the metal component was computed.

The residual rate, adsorption rate and recovery rate of each element were calculated by the following equation.

Residual rate (%) = elemental amount / amount of additive element in the upper solution

Adsorption rate (%) = 100-retention rate

Recovery rate (%) = element amount / addition element amount in the eluate

Test result

(1) Effect of pH

In the above-mentioned experimental method, the pH of the metal mixed solution was changed between pH 3.23-6.73, the adsorption test with respect to the chelate resin was performed, and the recovery rate and residual rate of Mo, V, and W were computed. As the buffer, an acetate-sodium acetate buffer was used in the range of pH 3.23 to 5.32, and sodium hydrogen phosphate, 12-hydrogen-dihydrogen phosphate buffer in the range of pH 5.78 to pH 6.73.

The calculation result of a recovery rate is shown in FIG. 1, and the calculation result of a residual rate is shown in Table 1 below.

Table 1 Mo, V, W recovery and residual rate at each pH Mo V W pH Recovery% Remaining percentage Recovery% Remaining percentage Recovery% Remaining percentage 3.23 52.2 23.3 3.28 78.5 8.83 85.0 18.6 3.50 76.7 10.3 82.4 21.3 3.93 57.7 35.6 4.01 85.1 10.3 84.7 19.9 4.18 59.7 38.3 4.43 92.4 9.61 85.4 20.9 4.61 67.9 31.1 4.98 96.5 6.97 86.0 18.2 5.15 49.3 48.9 5.32 95.2 5.88 93.5 15.1 5.78 99.2 11.0 89.8 11.5 5.96 31.6 79.2 6.32 46.9 56.4 89.7 9.48 6.73 49.1 52.6 74.1 23.8 34.4 76.1

From FIG. 1, it turns out that Mo gradually recovers with increasing pH from pH3.23, and recovery becomes 90% or more between pH4.43-pH5.78. From Table 1, since 5-10% of Mo was not adsorbed to the chelating resin in the pH range, the adsorbed Mo can be almost recovered.

In addition, the recovery rate of V was nearly 90% in the pH range of pH3.23 to pH6.32.

Regarding W, the maximum recovery was 67.9% at pH4.61, and the recovery was lower than Mo and V. Although W was difficult to adsorb | suck to chelate resin itself from the residual ratio shown in Table 1, it can be said that W adsorbed to the chelate resin can be completely eluted by hydrogen peroxide.

In addition, as a cause of the decrease in the adsorption rate of W to the chelate resin, when Mo (VI) is at pH 4 or higher, the amount of mononuclear MoO ₄ ² -species species rapidly increases, which becomes dominant in complexation with the chelate resin. , Mo and imino-diacetic acid chelate resin complexes, whereas in W (VI), the presence of complex polynuclear anion species dominates at pH <6, which makes it difficult to adsorb to the resin. do.

(2) Effect of Hydrogen Peroxide Temperature

In the above-mentioned experimental method, the test was performed by changing the temperature of the hydrogen peroxide water at the time of an elution process. The calculation result of the recovery rate of a metal component is shown in FIG.

As is apparent from FIG. 2, the liquid temperature was changed from room temperature to 90 ° C. at the time of elution in hydrogen peroxide water, but no significant change in recovery was found.

 (3) Effect of Hydrogen Peroxide Concentration

 In the above-mentioned experimental method, the hydrogen peroxide water used at the time of an elution process was diluted with ultrapure water, the hydrogen peroxide water of the density | concentration of 30 to 0.001 weight% was prepared, and the test was done. The relationship between the concentration of hydrogen peroxide and the recovery rate of the metal component is shown in the graph of FIG. 3.

As apparent from Fig. 3, Mo and V had the highest recovery rate when the hydrogen peroxide concentration was 30%, and a recovery rate close to 100% was obtained. In W, the recovery was maintained up to a low concentration range of 0.1% hydrogen peroxide.

<Example 2>

Metal mixed solutions containing the metal ions shown in Table 2 below at a concentration of 0.67 mg / kg were prepared, respectively. 15 mL of this metal mixture solution was added to the centrifuge tube, and pH was adjusted to 5.1 with the buffer solution. Subsequently, 0.5 g of weakly acidic cation exchange resins having the same sodium imino diacetate group as used in Example 1 was added to the metal mixture, followed by stirring with a magnetic stirrer for 2 hours. Thereafter, centrifugation was performed at 3500 rpm for 12 minutes, and the supernatant solution was subjected to ICP mass spectrometry (ICP-MS) and ICP emission spectrometry (ICP-AES) to calculate the residual and adsorption rates of the metal components.

Subsequently, 30 mL of hydrogen peroxide water (concentration 1% by weight) was added to the chelate resin, and left to stand for 2 minutes to elute the adsorbed metal.

Subsequently, ICP-MS measurement and ICP-AES measurement were performed about the eluate similarly to Example 1, and the recovery rate of the metal component was computed. The results are shown in Table 2 below and FIG. 4.

Instead of 30 mL of 0.1% hydrogen peroxide solution, 10 mL of 2 mol / L nitric acid, 10 mL of 2 mol / L hydrochloric acid, or 10 mL of 2 mol / L sulfuric acid was used in the same manner as described above to adsorb the chelate resin. The metal was eluted. About the eluate, the calculation result of the recovery rate of a metal component is shown in following Table 2 and FIGS. 5-7.

TABLE 2 Metal recovery rate by each eluate Recovery rate [%] element H ₂ O ₂ ^a) HNO ₃ HCl H ₂ SO ₄ Mo 98.7 ± 0.6 83.5 71.7 71.1 V 102 ± 1 74.2 72.2 74.1 W 62.7 ± 1.6 74.8 76.6 87.6 Al 0.13 ± 0.16 74.3 67.3 57.3 Cr 0.59 ± 0.06 7.98 12.0 10.7 Mn 0.20 ± 0.23 57.0 30.9 30.1 Fe ^b) 84.1 79.5 85.4 Co 0.34 ± 0.22 79.5 64.7 58.1 Ni 0.11 ± 0.12 72.0 52.1 48.6 Cu ^b) 88.0 73.5 63.1 Zn 0.33 ± 0.41 102 95.8 69.4 Ga 0.99 ± 0.18 65.3 55.7 51.1 Y 0.41 ± 0.43 83.3 70.4 66.6 Zr 2.6 ± 0.04 36.3 41.3 55.1 CD 0.57 ± 0.55 98.2 71.6 74.8 Sn 0.17 ± 0.14 0.06 0.33 0.16 La 0.36 ± 0.37 88.7 79.4 76.2 Ce 0.40 ± 0.34 88.2 77.1 74.1 Pr 0.36 ± 0.36 88.3 77.1 73.2 Nd 0.34 ± 0.34 89.2 81.2 79.4 Sm 0.33 ± 0.34 87.2 79.9 77.6 Eu 0.34 ± 0.35 88.2 79.5 75.6 Gd 0.37 ± 0.37 96.1 84.8 81.6 Tb 0.41 ± 0.43 90.4 76.2 73.6 Dy 0.44 ± 0.46 93.0 81.6 80.4 Ho 0.47 ± 0.48 91.9 78.3 76.4 Er 0.48 ± 0.49 92.5 82.3 80.5 Tm 0.53 ± 0.52 92.7 78.6 76.8 Yb 0.53 ± 0.52 91.4 83.9 82.6 Lu 0.56 ± 0.54 94.1 77.7 76.8 Pb 0.28 ± 0.24 101 89.7 91.5

a) output as n = 3 b) below detection limit

As apparent from the above results, when nitric acid, hydrochloric acid and sulfuric acid were used as the eluent, hydrogen peroxide water was used as the eluent, while the metal components adsorbed to the chelate resin had no particular selectivity and the various types of metals were simultaneously recovered. In the case, it can be seen that it can recover with high selectivity only for molybdenum, vanadium and tungsten.

<Example 3>

In Example 1, 10 mL of 2 mol / L nitric acid was added to the chelate resin subjected to the elution treatment with hydrogen peroxide water, and the metal remaining in the chelate resin was eluted. Then, 10 mL of 2 mol / L sodium hydroxide aqueous solution was added, and it left for 2 minutes, and wash | cleaned with ultrapure water and regenerated resin.

Subsequently, in the same manner as in Example 1, using a chelate resin dried with a drier, adsorption test of the metal component from the mixed solution containing Mo, V and W, and elution test with 30% hydrogen peroxide solution were carried out. The recovery rate of the component was calculated.

In the same manner as in the above method, the regeneration treatment of the chelate resin and the adsorption and elution treatment of the metal component were repeatedly performed.

In Table 3 below, the results of calculation of the recovery rates of Mo, V, and W in the use times 1 to 4 of the chelate resin are shown.

TABLE 3 Change rate of recovery of Mo, V, W by the number of chelate resins used Recovery rate ^a) [%] element 1st time 2nd time 3rd time 4th Mo 98.2 ± 0.6 95.2 ± 0.2 108 ± 1 103 ± 4 V 102 ± 1 98.1 ± 0.01 106 ± 3 102 ± 2 W 62.7 ± 1.6 83.8 ± 5.6 83.4 ± 2.7 75.5 ± 2.9

a) output as n = 3

As is apparent from the above results, even when the chelated resin after the metal component eluted was treated with nitric acid and reused, it was found that the recovery rate of the same metal component as in the first treatment was maintained. From this result, it was confirmed that the chelate resin used in the above method can be reused even when the metal is eluted with hydrogen peroxide solution without destroying the functional group.

<Example 4>

0.3 g of the incineration fly ash collected by the bottom ash and fly ash mixture at the Tokushima City waste incineration plant was shaken in 110 ml of 2 mol / L nitric acid for 4 hours at 110 ° C. to extract a metal component. 2 ml of the obtained extract was added to a centrifuge tube and adjusted to pH 4.7 with a buffer.

Subsequently, 0.7g of weakly acidic cation exchange resin which has the same sodium imino diacetic acid group as used in Example 1 was added to this metal mixture liquid, and it stirred with the magnetic stirrer for 2 hours. Thereafter, the mixture was centrifuged at 3500 rpm for 12 minutes, and then the supernatant solution was subjected to ICP mass spectrometry (ICP-MS) and ICP emission spectrometry (ICP-AES). Calculated.

Subsequently, the metal adsorbed to the chelate resin was eluted in the same manner as in Example 1 using 50 mL of 1 wt% hydrogen peroxide water or 10 mL of 30 wt% hydrogen peroxide water.

About the eluate, the ICP-MS measurement and the ICP-AES measurement were performed, and the recovery rate of the metal component was computed.

The results when eluted with 30 wt% hydrogen peroxide water are shown in Table 4 and FIG. 8, and the results when eluted with 1 wt% hydrogen peroxide water are shown in Tables 5 and 9 below.

Table 4 Recovery rate of each element of incineration fly ash extract when eluted with 30% hydrogen peroxide element Recovery rate ^a) [%] Relative standard deviation [%] Adsorption rate [%] Mo 94.6 ± 5.2 5.5 97.6 V 107 ± 5.6 5.3 98.3 W 62.5 ± 7.9 12.6 90.5 Al 0.8 ± 0.03 3 88.5 Cr ^b) 3.4 Mn 0.7 ± 0.09 13.0 81.1 Fe 2.3 ± 0.1 6 95.0 Co 2.9 ± 0.1 3.5 95.5 Ni 2.4 ± 0.3 13.3 98.0 Cu 3.8 ± 0.3 7.3 98.4 Zn 1.0 ± 0.02 1.7 99.5 Ga 3.7 ± 0.2 5.9 83.2 Y 0.5 ± 0.03 5.2 82.3 Zr 12 ± 1.6 14.2 18.9 CD 1.1 ± 0.2 21.4 92.9 Sn 3.2 ± 0.5 15.4 88.7 La 0.1 ± 0.007 6.6 87.8 Ce 0.3 ± 0.03 10.6 88.5 Pr 0.1 ± 0.007 5.0 86.1 Nd 0.1 ± 0.02 12.7 82.0 Sm ^b) 77.1 Eu 0.2 ± 0.1 43.8 78.0 Gd 0.1 ± 0.1 81.8 74.7 Tb 0.3 ± 0.1 57.0 78.5 Dy 0.4 ± 0.1 29.7 81.3 Ho 0.5 ± 0.2 36.2 81.3 Er 0.6 ± 0.2 31.2 83.2 Tm 0.7 ± 0.3 52.7 78.1 Yb 0.7 ± 0.2 27.6 84.4 Lu 0.7 ± 0.4 51.4 78.6 Pb 0.6 ± 0.2 38.1 83.0

a) yielding n = 3

b) below detection limit

Table 5 Recovery rate of each element of incineration fly ash extract when eluted with 1% hydrogen peroxide element Recovery rate ^a) [%] Relative standard deviation [%] Adsorption rate [%] Mo 82.9 ± 7.3 8.8 97.7 V 82.2 ± 6.5 7.9 97.7 W 63.4 ± 8.8 13.9 83.7 Al 1.3 ^b) 71.5 Cr 2.5 ± 0.9 33.8 Mn 0.8 ± 0.4 51.1 78.0 Fe 0.5 ^b) 84.7 Co 1.5 ± 0.9 61.6 95.6 Ni 2.6 ± 1.7 65.3 97.5 Cu 1.4 ^b) 95.0 Zn 0.7 ^b) 99.5 Ga 1.2 ^b) 71.8 Y 1.0 ± 1.0 98.3 86.2 Zr 7.0 ± 2.4 34.1 42.0 CD 0.7 ^b) 95.0 Sn 2.6 ^b) 78.5 La 0.7 ± 0.6 95.2 84.7 Ce 0.7 ± 0.6 81.7 84.4 Pr 1.0 ± 0.4 41.7 82.1 Nd 0.5 ± 0.5 104 78.2 Sm 0.7 ± 0.3 48.0 76.2 Eu 1.0 ± 0.8 75.9 75.8 Gd 0.3 ± 0.7 215 77.5 Tb 0.2 ± 0.8 324 84.6 Dy ^c) 88.0 Ho 0.9 ± 0.8 82.4 88.3 Er ^c) 89.4 Tm 0.8 ± .0.5 58.2 87.9 Yb ^c) 92.7 Lu ^c) 87.7 Pb 0.7 ± 0.4 51.7 79.9

a) yielding n = 3

b) yielding n = 2

c) limit of detection

As is clear from the above results, in the case where 1% by weight hydrogen peroxide water and 30% by weight hydrogen peroxide water were used as the eluent, in all cases, Mo, V, and W were selectively recovered. When 1% by weight of hydrogen peroxide water was used, the recovery rate was lower than that when 30% by weight of hydrogen peroxide water was used, but about 80% recovery was obtained with Mo and V.

Moreover, in the method of this invention, it can be said that 70% or more of metal ions containing harmful heavy metal ions, such as Cd and Pb except Cr and Zr, can be adsorb | sucked in an extract liquid, and it is effective also to detoxify an extract liquid.

Example 5

5 Ml of 8 g / L magnesium nitrate aqueous solution was collected into the centrifuge tube, and ammonium molybdate, ammonium vanadate, and ammonium tungstate pentahydrate were added to a concentration of 200 μg L ⁻¹ , respectively, and ultrapure water was added to make the total amount 45 mL. . After adding 5 mL of 30% ammonium water to this solution, stirring for 5 minutes, it was left still.

Subsequently, centrifugation was performed at 3500 rpm by the centrifuge, and decantation was performed. After wash | cleaning the obtained precipitation with ultrapure water, 1.5 ml of 30 weight% hydrogen peroxide water was added, it stirred, and was left overnight.

Subsequently, the centrifugal separator was centrifuged at 3500 rpm, and the upper part was filtered with the hole diameter 0.45 mm filter. 1 mL of 69% concentrated nitric acid was added to the obtained supernatant to 9 mL with ultrapure water, and then 1 mL of a standard element solution containing each element of In, Re, and Tl was added at a concentration of 100 mg L ⁻¹ for inductively coupled plasma mass spectrometry analysis. What made it the measurement solution.

About the measurement solution prepared by the above-mentioned method, ICP-MS measurement was performed and the recovery rate of a metal component was computed. The results are shown in Table 6 below.

Table 6 Recovery of V, Mo, and W by Elution Treatment from Magnesium Precipitation with 30% Hydrogen Peroxide Recovery% V 18.7 ± 7.8 Mo 43.4 ± 10.9 W 43.4 ± 11.0

<Example 6>

At a concentration of 10 mg L- ¹ , add 1 mL of an aqueous solution containing each element of V, Mo, W, Mn, Co, Zn, Re, and Tl and 10 g of 0.1 mol L- ¹ acetate / sodium acetate buffer to the centrifuge tube, After adding 0.3g of weakly acidic cation exchange resin which has the same sodium imino diacetic acid group as used in Example 1, it stirred for 120 minutes by the magnetic stirrer. Subsequently, after extracting a supernatant, 10 g of ultrapure water was added to wash the resin.

On the other hand, 12.5 weight% of sodium percarbonate aqueous solution was prepared using ultrapure water, and this was made into the eluent.

The sodium percarbonate aqueous solution 10g mentioned above was added to the chelate resin wash | cleaned by the method mentioned above, and it stirred for 120 minutes with the magnetic stirrer. The supernatant and the eluate were diluted, and after addition of 1 mL of the same internal standard element liquid used in Example 5, ICP-MS measurement was performed for each solution to calculate the recovery of each metal. The results are shown in Table 7 below.

TABLE 7 Recovery of Chelate Resin and Adsorption Metal by Percarbonate Aqueous Solution element Recovery rate for percarbonate solution V 62.5 Mo 75.9 W 54.6 Mn 1.20 Co 0.05 Zn 0.1 Re 2.89 Tl 1.08

Claims (5)

A selective recovery method for rare metals, comprising the following steps (1) and (2): (1) Rare metal by a method of contacting an aqueous solution containing a metal component containing a rare metal with a chelating resin or an adsorbent, or by forming a precipitate of the metal compound in an aqueous solution containing a metal component containing a rare metal. Adsorbing or occluding a metal component in a solid phase; (2) A step of contacting an aqueous solution containing a peroxy compound with a solid phase obtained by adsorbing or occluding a metal component including the rare metal obtained in the step (1). The method according to claim 1, The selective recovery method of the rare metal in which the chelate resin used at a process (1) is resin containing an imino diacetic acid group or its salt. The method according to claim 1 or 2, The rare metal of precipitation which is formed in step (1) is a precipitate containing at least one component selected from the group consisting of aluminum hydroxide, magnesium hydroxide, gallium hydroxide, iron hydroxide, manganese hydroxide, manganese oxide, indium hydroxide, and a rare earth element hydroxide. Selective recovery method. The method according to any one of claims 1 to 3, The selective recovery method of the rare metal in which the peroxy compound used at a process (2) is at least 1 sort (s) of component chosen from the group which consists of sodium percarbonate, hydrogen peroxide, and ozone. Selective recovery of the rare metal by the method according to any one of claims 1 to 4, followed by washing the used chelating resin or adsorbent with an acid aqueous solution and reusing in the step (1). Recovery method.

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