JP2001164326A - Biopolymer composite cesium selective ion exchanger and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biopolymer composite cesium selective ion exchanger having excellent handling quality and a method for manufacturing the same which is simple and is good in reproducibility. SOLUTION: A cesium separating and recovering agent consisting of the biopolymer composite cesium selective ion exchanger is obtained by using a calcium alginate gel as a carrier and depositing an inorganic ion exchanger (excluding ammonium phosphomolybdate) thereon and the method for manufacturing the same is provided. Accordingly, the biopolymer composite cesium selective ion exchanger has the excellent handling quality and facilitates the separation of solid from liquid and is therefore usable for adsorption separation processes of both of a contact filtration method and a fixed phase adsorption method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for selectively and efficiently separating and recovering a small amount of dissolved cesium from a solution to be treated in which various components coexist in various fields such as resource recovery and wastewater treatment or analytical chemistry. And a method for producing the same.

[0002]

2. Description of the Related Art Cesium is a kind of metal element which is used in the manufacture of reagents, photoelectric conversion elements, optical crystals, optical glasses, etc., and has a relatively high average price, and is associated with other alkali metals as a resource. Although it is widely distributed in the natural world, its amount is extremely small and the average core content is 3 g / t ("General Geochemistry", pp. 54-55, Iwanami Shoten (1979)). Cesium is mainly produced from cesium ore porcite, and is also recovered as a by-product when producing lithium and potassium from lepidolite and carnallite (“Rare Metal Data Book”, edited by Metal Mining Corporation ( 1968)). However, since these ore resources are ubiquitous on the earth, selective extraction from seawater or geothermal water that dissolves cesium, although in a trace amount, is being studied from the viewpoint of securing resources (doctoral dissertation, engineering No. 1603,
Tohoku University). In addition, the radioactive isotope cesium-137
Since isotope can be used as a radiation source in medicine or various industrial fields, the selective recovery of the isotope from radioactive liquid waste is an important issue to be studied from the viewpoint of volume reduction treatment and effective utilization of radioactive liquid waste ( IAEA Technical Rep. Serie
s, No. 356, 1993).

[0003] As a method for selective separation and recovery of cesium slightly dissolved in an aqueous solution, a cation exchange resin method (for example, "I"
on Exchangers in Analytical Chemistry. Their Prope
rties and Use in Inorganic Chemistry ", 14, 170-17
3, Elsevier (1982)), inorganic ion adsorption method (eg, "
Ion Exchangers in Analytical Chemistry. Their Prop
erties and Use in Inorganic Chemistry ", 14, 173-19
0, Elsevier (1982)) and solvent extraction methods (for example, "Handbook of Solvent Extraction", 202; 403, Technica Publishing, Kiev (1972)). However,
At the present stage, in terms of recovery cost, selective recovery from the solution to be treated with an inorganic ion exchanger is considered to be the most practical method (Doctoral Dissertation, Engineering No. 1603, Tohoku University). This is because inorganic ion exchangers generally have higher selectivity for specific ions or groups than organic ion exchangers (“Ion exchange, basics of advanced separation technology”, Kodansha Scientific (1991)), and are resistant to heat and heat. This is due to its excellent physicochemical properties such as radioactivity ("Topics in Inorg
anic & General Chemistry ", Elesevier, Amsterdam (19
64)).

As an inorganic ion exchanger having high selectivity for cesium, zeolite (Zeolite Molecular S)
ieves-Structure, Chemistry, and Use ", John Wiley &
Sons (1974)), crystalline tetratitanic acid (Nikka Kagaku, 10, 1656)
(1981)), smectite (Clays Clay Min., 28, 142)
(1980)), insoluble ferrocyanide (Proc. Of the Sy
mp.on Waste Management, Tucson, 2, 1687 (199
3)), ammonium phosphomolybdate (Nature, 181, 15
30 (1958)), silico titanate (Ind. Eng. Chem. Re
s., 33, 2702 (1994)) and the like.

Among them, in particular, the insoluble ferrocyanide, ammonium phosphomolybdate and silicotitanate have a remarkably higher cesium selectivity than those of other inorganic ion exchangers, and are therefore one of the typical multi-component treatment solutions. It is expected to be used as a radioactive liquid waste treatment agent (Radiochimica Acta, 40, 49-56 (1986)). But,
In the case of an insoluble ferrocyanide, it is known that elution of adsorbed cesium is extremely difficult although cesium selectivity is high, and this is a major problem from the viewpoint of recovery and utilization. In addition, in the case of silico titanate, there is a problem that the cesium selectivity is greatly reduced due to the unstable structure in a low pH region (Ind. Eng. Chem. Res., 33, 2702 (19)
94)). Furthermore, in the case of ammonium phosphomolybdate, cesium adsorbed is completely eluted and recovered with an ammonium salt solution despite high acid resistance and extremely high cesium selectivity, and at the same time, the ion exchanger can be regenerated. (Nature, 181, 1530 (1958)), it is expected to be the most practical as an inorganic ion exchanger for separation and recovery of cesium (Radiochimica Acta, 40, 49 (1
986)), but ammonium phosphomolybdate synthesized by a conventional method is in the form of a fine powder (J. Inorg. Nucl. Chem, 27, 227).
(1965)), there was a problem in handleability in liquid contact or solid-liquid separation.

For this reason, for example, asbestos (J. Inorg. Nucl. Chem, 12, 95 (1959)) and silica gel (J. Radioanal) have been used for the purpose of improving the handleability of the inorganic ion exchanger. Chem., 21, 381 (1974)),
Amberlite XAD-7 (J. Radioanal. Chem., 56, 13
(1980)), polyacrylonitrile (Sep. Sci. Techno
l., 32, 37 (1997)) or titanium phosphate ("Progres
s in Ion Exchange-Advances and Applications ", pp.2
89-297, Royal Society of Chemistry (1995)) and the like.

[0007]

However, all of the above-mentioned complexing methods have the problem that the preparation operation is complicated and the ion exchange characteristics of the resulting complex lack reproducibility (Radiochi
mica Acta, 40, 49 (1986)), but there is no practical use at all. Therefore, development of a new method for shaping the inorganic ion exchanger which is simple and excellent in reproducibility has been urgently required.

The present invention has been made in view of the above circumstances, and is particularly directed to a new method for shaping an inorganic ion exchanger, specifically, to an efficient adsorption / separation process of cesium from various solutions. It is an object of the present invention to provide a novel biopolymer composite cesium-selective ion exchanger which can be applied and a method for producing the same, which is simple and excellent in reproducibility.

[0009]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that an inorganic ion exchanger having high cesium selectivity (however, ammonium phosphate molybdate is added to calcium alginate gel). Except for the above, a composite ion exchanger with good handleability, in which cesium is dispersed and supported, can be used to selectively adsorb, separate, and recover trace amounts of cesium from various solutions with high coexisting salt concentrations using columns packed with this. Have found and completed the present invention.

The present invention comprises the following technical means. (1) Cesium separation / recovery characterized by comprising a cesium-selective complex ion exchanger obtained by using a calcium alginate gel as a carrier and carrying an inorganic ion exchanger (excluding ammonium phosphomolybdate) on the carrier. Agent. (2) The cesium separation / recovery agent according to the above (1), wherein the inorganic ion exchanger is one selected from ammonium tungstophosphate and potassium hexacyanoferrate (II) copper (II). (3) The method for producing a composite ion exchanger according to the above (1), wherein a slurry prepared by dispersing a powder of the inorganic ion exchanger in a sodium alginate solution is brought into contact with a calcium salt solution to thereby form alginate. A production method comprising dispersing and supporting an inorganic ion exchanger in a calcium gel carrier. (4) As a contact method between the slurry and the calcium salt solution,
The production method according to (3), wherein the former is dropped into the latter solution to form a granular composite ion exchanger. (5) As a contact method between the slurry and the calcium salt solution,
The method according to (3), wherein the former is extruded into the latter solution to form a fibrous composite ion exchanger. (6) The production method according to the above (3), wherein the slurry is formed into a film and then contacted with a calcium salt solution to form a film-like composite ion exchanger.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. That is, the first aspect of the present invention comprises a biopolymer composite cesium-selective ion exchanger in which an inorganic ion exchanger (excluding ammonium phosphomolybdate) is supported and complexed in a calcium alginate gel. It is a cesium separation / recovery agent characterized by the following. The formation of the composite cesium-selective ion exchanger is easily confirmed by the powder X-ray diffraction measurement of the composite sample by the appearance of a diffraction peak attributed to the inorganic ion exchanger on the powder X-ray diffraction pattern. The calcium alginate gel itself serving as a carrier is X-ray amorphous and does not show any diffraction peak.

A second aspect of the present invention provides a method of forming a composite of the above-mentioned inorganic ion exchanger in a carrier, wherein a water-soluble sodium alginate is used as a precursor of the carrier. This is a method for producing a neutral ion exchanger.

Further, the present invention has an embodiment in which a method of contacting the above-mentioned slurry with a calcium salt solution is adopted in order to adapt the shape of the composite ion exchanger to various use forms.

In the biopolymer composite cesium-selective ion exchanger of the present invention, the first step is to add the above-mentioned inorganic ion exchanger to a solution of sodium alginate and agitate to obtain a slurry of both. This slurry is brought into contact with a calcium salt solution to exchange exchangeable sodium ions in sodium alginate with calcium ions to form a calcium alginate gel, and an organic-inorganic material obtained by dispersing and supporting the inorganic ion exchanger therein. Complex.

As the inorganic ion exchanger, for example, ammonium tungstophosphate (NH ₄ ) ₃ PO ₄ .12
(WO ₃ ) · 3H ₂ O, general formula K _2-x Cu _{x / 2} [CuF
e (CN) ₆ ] · nH ₂ O (where n represents the number of moles,
n is different depending on the value of x) potassium hexacyanoferrate (II), basic salts such as hydrotalcite, acid salts such as zirconium phosphate, various hydroxides and hydrated oxides Is exemplified, but not limited to these,
Other suitable inorganic ion exchangers (excluding ammonium phosphomolybdate) are used. Examples of the calcium salt solution include calcium nitrate and calcium chloride solutions. As long as the compound dissociates in the solution to release calcium ions, a salt solution thereof can be used regardless of an organic compound or an inorganic compound.

By changing the method of contacting the slurry with the calcium salt solution, the shape of the composite ion exchanger can be adapted to various use forms. As a method for contacting the slurry with the calcium salt solution, a method in which the slurry is dropped into a calcium salt solution to form a granular composite ion exchanger, and the slurry is extruded into a calcium salt solution by a syringe or the like and formed into a fibrous form. A method of forming a composite ion exchanger of the present invention, a method of forming a film by applying the slurry thinly and uniformly on a flat plate, and then contacting with a calcium salt solution to form a film-like composite ion exchanger; Is exemplified.

Cesium is adsorbed and separated from the solution to be treated by the highly selective adsorption of cesium ions of the inorganic ion exchanger dispersed and supported in fine particles in the organic-inorganic composite. Cesium adsorbed and separated from the solution to be treated by the composite cesium-selective ion exchanger is easily eluted and recovered using a mixed solution of an ammonium salt solution and various acid solutions as an eluent, and at the same time, the composite cesium-selective ion exchanger is used. Since the ion exchanger can be regenerated, the biopolymer composite cesium-selective ion exchanger of the present invention has a high separation / recovery effect on trace amounts of cesium in various treatment solutions having a high coexisting salt concentration. I have. Therefore, by using the composite cesium-selective ion exchanger according to the present invention, it is possible to easily and efficiently separate and recover cesium from various solutions to be treated.

The biopolymer composite cesium-selective ion exchanger of the present invention is a novel composite inorganic ion exchanger which can take any shape formed by supporting and complexing an inorganic ion exchanger in a calcium alginate gel carrier. As the raw materials, sodium alginate and inorganic ion exchangers are readily available and commercially available. The chemical composition of the composite cesium-selective ion exchanger cannot be represented by the general formula because it differs depending on the composition of the sodium alginate used and the composite ratio of the inorganic ion exchanger, but the inorganic ion is determined by powder X-ray diffraction measurement of the composite sample. The main diffraction peak attributed to the exchanger is clearly seen, and its generation is also confirmed. The infrared absorption spectrum of the same sample, line analysis with an X-ray microanalyzer, and energy dispersive spectrum measurement indicate that the inorganic ion exchanger is It is easily confirmed that the particles are uniformly dispersed and supported in the gel.

[0019]

When the composite ion exchanger of the present invention is brought into contact with various solutions to be treated containing cesium, the surface characteristics of these composite ion exchangers, that is, they are dispersed and supported in fine particles in the composite ion exchanger. Due to the ion sieving action of the inorganic cation exchanger, only cesium ions are selectively adsorbed and separated from the solution. Further, the cesium ions adsorbed on the composite ion exchanger can be easily eluted and recovered using a mixed solution of an ammonium salt solution and various acid solutions as an eluent, and the composite ion exchanger can be regenerated at the same time. Therefore, by using the composite ion exchanger of the present invention, it is possible to simply and efficiently separate and recover cesium from various solutions containing cesium ions such as seawater, geothermal water, and radioactive waste liquid.

[0020]

Next, the present invention will be specifically described based on examples, but the present invention is not limited to the examples. Example In this example, ammonium tungstophosphate (WP) was used as an inorganic ion exchanger on a calcium alginate gel.
Potassium copper (II) hexacyanoferrate (II) (CuF
For the granular gel sample supporting and complexing C), the separation / recovery capacities of the two types of prepared granular biopolymer composite cesium-selective ion exchangers were measured using commercially available WP, synthetic CuFC,
And that of the carrier calcium alginate.

1. Preparation of granular biopolymer composite cesium selective ion exchanger sample The biopolymer composite cesium selective ion exchanger sample of the present invention is prepared as follows. That is, an appropriate amount of commercially available sodium alginate powder is dissolved in distilled water to obtain an aqueous solution having an appropriate viscosity. Next, an appropriate amount of commercially available WP and synthetic CuFC powder is added to the aqueous sodium alginate solution and stirred to form a uniform slurry. This slurry is dropped into a calcium salt solution, and sodium ions in sodium alginate are ion-exchanged with calcium ions to obtain a particulate calcium alginate gel in which the inorganic ion exchanger is dispersed and supported. The granular calcium alginate gel obtained here is dried to produce the granular biopolymer composite cesium-selective ion exchanger of the present invention. Hereinafter, examples of producing two types of granular biopolymer composite cesium-selective ion exchangers will be described.

1.1 Method (1) Preparation of calcium alginate-ammonium tungstophosphate complex 10 g of sodium alginate powder (manufactured by Komune Chemical) and commercially available ammonium tungstophosphate ((NH ₄ ) ₃ PO ₄ )
・ 12 (WO ₃ ) ・ 3H ₂ O (manufactured by Wako Pure Chemical Industries)
After adding to L of distilled water, they were kneaded well to obtain a uniform slurry. On the other hand, 28 g of commercially available calcium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 400 mL of distilled water, dissolved by stirring, and further distilled water was added so that the total liquid volume was 500 mL, and 0.5 M (M = mol / L, hereinafter abbreviated as M).

This 0.5M calcium chloride aqueous solution 500
While stirring the mL at a constant speed with a stirrer (200 rpm),
The slurry was dropped into the slurry at a flow rate of 2 mL / min with a metering pump. In order to stabilize the formed gel, the whole amount of the slurry was dropped, and the mixture was further stirred for 30 minutes. Next, the formed granular gel was separated from a 0.5 M calcium chloride aqueous solution and washed with distilled water. The granular gel after washing is dried in a dry oven at 50 ° C. for 12 hours, and the granular biopolymer composite cesium-selective ion exchanger-3 of the present invention (hereinafter referred to as “the ion-exchanger 3”)
GC-3).

(2) Preparation of calcium alginate-potassium copper (II) hexacyanoferrate (II) complex First, 5 g of commercially available sodium alginate powder (manufactured by Komune Chemical) was added little by little to 400 mL of distilled water while stirring. , Dissolve, add distilled water so that the total liquid volume becomes 500 mL, and stir to obtain 1 wt% of sodium alginate.
An aqueous solution was obtained. Next, 100 mL of this 1 wt% sodium alginate aqueous solution was added to the existing method (Separation Sci.
ence and Technology, 34 (1), 17-28 (1999)), potassium hexacyanoiron (II) (K2 _- xC).
It added u _{x / 2} [CuFe (CN) _6] · nH ₂ O) 2g, and kneaded well both to obtain a homogeneous slurry. This slurry was dropped into a 0.5 M aqueous solution of calcium chloride in the same manner as in (1) above, and the resulting granular gel was washed with water and dried, and then the granular biopolymer composite cesium-selective ion exchanger-4 of the present invention (hereinafter, referred to as “1”). GC-4).

1.2 Results All the dried samples were stored in a desiccator containing a saturated aqueous solution of ammonium chloride in order to keep the water content constant. According to the powder X-ray diffraction measurement results, the carrier calcium alginate showed no diffraction peak and was amorphous, and the diffraction patterns of GC-3 and GC-4 contained ammonium tungstophosphate in the former and those in the latter, respectively. Only the diffraction peak of potassium hexacyanoiron (II) was clearly recognized.

2. Performance evaluation of granular biopolymer composite cesium-selective ion exchanger sample In order to evaluate the performance of the biopolymer composite cesium-selective ion exchanger sample of the present invention, a solution to be treated containing various metal ions was prepared and used. The distribution ratio of various metal ions to the sample was measured by the batch method and the adsorption / separation and recovery experiments of cesium from nitric acid solution by the column method were performed.

2.1 Samples used for partitioning and column experiments In the partitioning experiment, the granular biopolymer composite cesium-selective ion exchanger sample prepared in 1 above was used: GC-3, GC
-4, and commercially available powdered WP, synthetic CuFC, and a calcium alginate sample as a carrier (hereinafter abbreviated as a carrier) were used as comparative samples. In the column experiment, GC-3 was used as a composite cesium-selective ion exchanger sample.

2.2 Solution to be used for distribution and column experiments 2.2.1 Solution to be treated for distribution experiment Two types of solutions to be treated were prepared and used. That is, 1) 10
1M HNO ₃ acidic solution containing ppm cesium ion, and 2) HNO ₃ acidic solution having different acid concentrations have respective metal ion concentrations of 10 ppm (Am only 2.1 ×
10 ^-9 M), cesium (Cs), sodium (Na), strontium (Sr), cobalt (C
o), europium (Eu) or americium (A)
The metal ion solution prepared by adding the nitrate of m) was used as the solution to be treated. The solution to be treated was trace amounts of Cs-137 and Na-2, respectively, as tracers.
2, Sr-85, Co-60, Eu-152 and Am-
241 was used.

2.2.2 Solution to be treated for column experiment Cesium nitrate was added to a mixed aqueous solution of 1M HNO ₃ -4.5M NaNO _{3 in} a nitric acid solution so that the cesium ion concentration was 7.5 × 10 ^-5 M. C as a tracer
The solution to which s-137 was added was used as the solution to be treated.

2.3 Distribution Experiment A 70 mL complex cesium-selective ion exchanger sample or a comparative sample described in 2.1 was placed in a 10-mL centrifuge tube, and 7 mL of the solution to be subjected to the distribution experiment described in 2.2 was placed in this. After addition, the mixture was kept in a constant temperature bath at 25 ° C. for 7 days while stirring gently to reach equilibrium, and then the solid-liquid was centrifuged (1).
(0.00 rpm, 10 minutes). The radiation intensity in 2 mL of the supernatant was measured, and the distribution ratio (Kd) was calculated from the change in the radiation intensity before and after adsorption by the following equation. Kd = [(Ai-Af) / Af] V / m (mL / g), where Ai and Af (cpm / mL) are the initial and equilibrium radiation intensity, m (g) is the sample weight, and V ( m
L) is the volume of the processing solution. As is clear from the above equation, the Kd value of the ionic species having a smaller Af value after the reaction, that is, the larger the amount of adsorption to the sample is, the larger the Kd value is.

Table 1 shows the measurement results of the distribution ratio (Kd, _Cs ) of cesium to various samples obtained from the 1 MHNO ₃ acidic solution.

[0032]

[Table 1]

As shown in Table 1, 1 MHNO_Three In solution
In this case, distribution of cesium to the carrier is hardly recognized. this
For commercial WP, GC-3 (WP-Alg) and synthetic
Kd of CuFC, GC-4 (CuFC-Alg)_Csvalue
Are 10 in the former, respectively.^Four The value of the order,
10 people^Three The value of the order is obtained, in each case 1M
HNO_Three A fairly large value for the distribution ratio from the solution
Indicated. From the results in Table 1, it can be seen that GC-3 and GC-4
Highly selective adsorption capacity for cesium ions
Are WP and CuFC dispersedly supported in these samples.
It is clear that this is the case.

[0034] indicates Cs was measured for GC-3 from different HNO ₃ acid solution concentrations, Sr, Co, Eu, the distribution ratio of Am and Na (Kd, _M ^{n +)} of the measurement results of Table 2.

[0035]

[Table 2]

As shown in Table 2, the HNO ₃ concentration was set at 0.
Although the adsorption of polyvalent metal ions such as Sr and Am is slightly observed in a solution as low as
At the NO ₃ concentration, only the distribution ratio of Cs is significantly higher than other metal ions, and it is clear that GC-3 shows remarkable selectivity for Cs.

[0037] shows GC-4 to Cs measured from 1M HNO ₃ solution, Sr, Co, Eu, Am and Na distribution ratio (Kd, _M ^{n +)} of the measurement results of Table 3.

[0038]

[Table 3]

As shown in Table 3, only the distribution ratio of Cs is remarkably higher than other metal ions, and it is clear that GC-4 shows remarkable selectivity for Cs.

2.4 Column Experiment 1.00 g of GC-3 was packed in a glass column having an inner diameter of 0.7 cm (sample volume = 3.6 mL, height of packed bed = 9.
4 cm), and a feed aqueous solution (7.5 × 10 ⁻⁵ MCsNO ₃ −4.5 M NaNO ₃ −) at 25 ° C. was added to the column.
1MHNO ₃ ) at a flow rate of 0.21 mL / min.
The γ-ray intensity of Cs-137 in the fractionated effluent was measured, and a breakthrough curve of cesium was created. Under the same conditions, the above feed solution (7.5 × 10 ⁻⁵ MCsNO ₃ −
4.5 M NaNO ₃ -1 MHNO ₃ ) was passed through, and 0.01
As a eluent, 5M NH ₄ NO ₃ -1MHN at 25 ° C. was applied to a 1 g GC-3 column on which 3 mmol of cesium was adsorbed.
After passing O ₃ , the γ-ray intensity of Cs-137 in the eluate fractionated and collected was measured to prepare an elution curve of adsorbed cesium.

The breakthrough curve and elution curve of cesium are shown in FIGS. 1 and 2, respectively. As is evident from FIG. 1, 169 mL (5% breakthrough, corresponding to about 47 times the packed volume) of 4.5 M NaNO ₃ -1 was obtained with only 1 g of the GC-3 column.
It can be seen that a trace amount of cesium can be selectively adsorbed and separated from the MHNO ₃ solution. The flow-through exchange capacity of cesium obtained from the breakthrough curve in FIG. 1 is 1.26 × 10 ⁻² mmol / g.
Met.

On the other hand, as shown in FIG. 2, the feed solution (7.5 × 10 ⁻⁵ MCsNO ₃ −4.5M NaNO ₃ −
Cesium selectively adsorbed on the GC-3 column from 1 MHNO ₃ ) contained 68 mL of 5 MH ₄ NO ₃ -1 MH.
It was found that elution and recovery were possible by passing the NO ₃ mixed solution (elution rate: 77%). Further, the GC-3 column was regenerated at the same time as the elution of cesium, so that it could be used repeatedly.

[0043]

As described above, the biopolymer composite cesium-selective ion exchanger according to the present invention is excellent in both handleability and adsorption performance, is extremely simple in the production method, and has good reproducibility. Regardless of the liquid method,
By contacting with the water to be treated, the ion-exchange properties of these biopolymer composite cesium-selective ion exchangers, i.e., ammonium tungstophosphate dispersed and supported in fine particles in the biopolymer composite cesium-selective ion exchanger Alternatively, cesium in the water to be treated can be selectively separated and recovered by a specific ion exchange action of potassium hexacyanoferrate (II) copper (II). Therefore, by using this biopolymer composite cesium-selective ion exchanger, it is possible to selectively separate and recover cesium from water to be treated such as seawater, geothermal water, or radioactive wastewater containing a small amount of cesium.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a breakthrough curve of cesium from a mixed solution of sodium nitrate and nitric acid by a GC-3 column.

FIG. 2 is an explanatory diagram showing an elution curve of cesium from a GC-3 column.

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[Procedure amendment]

[Submission Date] July 17, 2000 (2007.1)
7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

The present invention comprises the following technical means. (1) An inorganic ion exchanger is supported and complexed in a carrier.
Composed of a complex ion exchanger,
It has high selective adsorption and elution rate, and can be used for complex ion exchange.
The formation of the complex is inconsistent on the powder X-ray diffraction pattern of the composite sample.
Due to the appearance of diffraction peaks attributed only to ion exchangers
A cesium separation / recovery agent that can be easily identified.
Mix sodium formate and inorganic ion exchanger uniformly
The prepared slurry is brought into contact with a calcium salt solution.
With inorganic calcium ions in the carrier of calcium alginate gel
Calcium alginate gel prepared by the process of dispersing and supporting an ion exchanger as a carrier, and an inorganic ion exchanger (excluding ammonium phosphomolybdate)
A cesium separation / recovery agent comprising a cesium-selective complex ion exchanger obtained by carrying cesium. (2) The cesium separation / recovery agent according to the above (1), wherein the inorganic ion exchanger is one selected from ammonium tungstophosphate and potassium hexacyanoferrate (II) copper (II). (3) The method for producing a composite ion exchanger according to the above (1), wherein a slurry prepared by dispersing a powder of the inorganic ion exchanger in a sodium alginate solution is brought into contact with a calcium salt solution to thereby form alginate. A production method comprising dispersing and supporting an inorganic ion exchanger in a calcium gel carrier. (4) As a contact method between the slurry and the calcium salt solution,
The production method according to (3), wherein the former is dropped into the latter solution to form a granular composite ion exchanger. (5) As a contact method between the slurry and the calcium salt solution,
The method according to (3), wherein the former is extruded into the latter solution to form a fibrous composite ion exchanger. (6) The production method according to the above (3), wherein the slurry is formed into a film and then contacted with a calcium salt solution to form a film-like composite ion exchanger.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C22B 3/42 C22B 3/00 M (72) Inventor Takumichi Hayashi 3-chome Nankodaiminami, Izumi-ku, Sendai-shi, Miyagi 21-18-503 No. 72 (72) Inventor Takeo Ebina 20 F-term (reference) 4F017 AA01 BA13 BA15 CA06 CA17 CB01 CB03 CB05 DA01 DA03 4D025 AA01 AA09 AB18 AB39 BA02 BA22 BA25 BA27 4K001 AA42 BA21 BA22

Claims (6)

[Claims] Claims: 1. A calcium alginate gel as a carrier,
A cesium separating / recovering agent comprising a cesium-selective composite ion exchanger obtained by supporting an inorganic ion exchanger (except for ammonium phosphomolybdate) on this. 2. The cesium separation / recovery agent according to claim 1, wherein the inorganic ion exchanger is one selected from ammonium tungstophosphate and potassium hexacyanoferrate (II) copper (II). 3. The method for producing a composite ion exchanger according to claim 1, wherein a slurry prepared by dispersing a powder of the inorganic ion exchanger in a sodium alginate solution is brought into contact with a calcium salt solution. A production method comprising dispersing and supporting an inorganic ion exchanger in a carrier of a calcium alginate gel. 4. The method according to claim 3, wherein the method of contacting the slurry with the calcium salt solution comprises dropping the former into the latter solution to obtain a granular composite ion exchanger. 5. The process according to claim 3, wherein the slurry is contacted with the calcium salt solution by extruding the former into the latter solution to form a fibrous composite ion exchanger. 6. The method according to claim 3, wherein after forming the slurry into a film, the slurry is brought into contact with a calcium salt solution to form a film-like composite ion exchanger.