JPH11211889A - Separation method and chelate resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To selectively separate a transuranium element from radioactive waste liquid containing the transuranium element by using a chelate resin having n-octyl (phenyl)-N,N-diisobutylcarbamoyl-methylphosphine-oxide as functional group. SOLUTION: A chelate resin is one having n-octyl(phenyl)-N,N- diisobutylcarbamoyl-methylphosphine-oxide as functional group. By using this, a transuranium element can be selectively separated from radioactive waste liquid containing the transuranium element. Consequently, waste liquid is easily disposed. In particular, it is favorable to be used for separation of an actionids element, particularly the transuranium element from low or middle level waste liquid. because in CMPO, -PO and -CO coordinated to metal ion do not accompany aicd dissociation, it can be used for disposal of waste liquid of high acid level by a purex process. Consequently, lanthanide element and/or actinide element can be selectively separated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel chelate resin for collecting metal ions and a separation method using the chelate resin, and more particularly to a method for removing transuranium elements from radioactive waste liquid discharged in spent nuclear fuel reprocessing. The present invention relates to a separation method expected to be applied to separation.

[0002]

BACKGROUND OF THE INVENTION In the reprocessing of spent nuclear fuel, one of the most important issues is the amount of waste discharged and how to reduce its toxicity. Developing good waste treatment is an important theme that will determine the future of nuclear power.

[0003] n-octyl (phenyl) -N, N-diisobutylcarbamoylmethylphosphine oxide (C
MPO) is known as an extractant for removing actinides and lanthanoids from acidic liquid radioactive wastes [Vandegrift, GF, Leonard, RA, Steind
ler, MJ, Horwitz, EP, Basile, LJ, Diamond, H., Kalin
e, DG, Kaplan, L.: Argonne National Laboratory Repor
t ANL-84-45 (1984), Horwitz, EP, Kalina, DG, Diamon
d, H., Vandegrift, GF, Schulz, WW: SolventExtr.Ion E
xch., 3,75 (1985), Horwitz, EP, Kalina, DG, Diamond,
H., Kaplan, L., Vandegrift, GF, Leonard, RA, Steindle
r, MJ, Schulz, WW: DE85 010251 (1985)].

Accordingly, when CMPO is used, the extraction equilibrium between the actinoid element and the lanthanoid element,
Studies on the structural and kinetic studies on metal complexes formed between Kalina, DG, H
orwitz, EP, Kaplan, L., Muscatello, AC: Sep.Sci.Tech
nol., 16, 1127 (1981), Horwitz, EP, Kalina, DG, Kapla
n, L., Mason, GW, Diamond, H.: Sep.Sci.Technol., 17,126
1 (1982), Horwitz, EP, Martin, KA, Diamond, H., Kapla
n, L .: Solvent Extr.Ion Exch., 4,449 (1986), Marsh, S.
F., Yarbro, SL: DE88 007154 (1988), Nagasaki, S., Kino
shita, K., Enokida, Y., Suzuki, A.: J.Nucl.Sci.Technol.,
29,56 (1992), Wisnubroto, DS, Nagasaki, S., Enokida,
Y., Suzuki, A .: J. Nucl. Sci. Technol., 29, 263 (1992), Cau
dle, LJ, Duesler, EN, Paine, RT: Inorg.Chem., 24,44
41 (1985), Ikeda, Y., Miyata, A., Park, Y.-Y., Hatakeyam
a, K., Tomiyasu, H.: J.Nucl.Sci.Technol., 30,720 (199
3), Hatakeyama, K., Park, YY., Tomiyasu, H., Ikeda, Y .:
J. Nucl. Sci. Technol., 32, 1146 (1995), Sano, Y., Ozawa,
M., Okamoto, F., Tanaka, Y.: Solvent.Extr.Res.Dev.Jpn.,
3,164 (1996), Hatakeyama, K., Park, Y.-Y., Tomiyasu, H .:
Ikeda, Y .: J. Nucl. Sci. Technol., 34, 298 (1997)].

Among them, according to, for example, a study by nuclear magnetic resonance spectroscopy, CMPO is trivalent lanthanide having similar chemical properties to U (VI) and the trivalent actinide ions Am (III) and Cm (III). Ion, Ce (III), Nd (II
I) and La (III) have been shown to have strong coordination ability [Hatakeyama, K., Park, Y.-Y., Tomiyasu,
H., Ikeda, Y .: J. Nucl. Sci. Technol., 32, 1146 (1995)].

Further, as a system using CMPO,
A transuranium element extraction treatment method (TRUEX method) has been proposed as a solvent extraction system for treating liquid waste [Vande
grift, GF, Leonard, RA, Steindler, MJ, Horwitz, E.
P., Basile, LJ, Diamond, H., Kaline, DG, Kaplan, L.: Ar
gonne National Laboratory Report ANL-84-45 (1984),
Carnell.WT, Choppin, GR: "Plutonium Chemistry", Am
erican Society, Washington, DC, ACS Symposium Serie
s, 216, 433, (1983), Kolarik, ZJ, Horwitz, EP: Solven
t Extr.Ion Exch., 6,247 (1988), Schulz.WW, Horwitz,
EP: Sep. Sci. Technol., 23, 1191 (1988), Mincher, BJ:
Solvent Extr. Ion Exch., 7, 645 (1989)].

However, when solvent extraction is performed using CMPO as an extracting agent, there remains a troublesome problem such as formation of a third phase. To solve these problems, dihexyl-
Extraction chromatography has been developed using styrene-divinylbenzene (SDB) copolymer impregnated with N, N-diethylcarbamoylmethylphosphonate (CMP) or CMPO as an adsorbent [Takeshita, K. Kumag
ai, M., Takashima, Y., Matsumoto, S.: J.Chem.Eng.Jpn., 2
7,52 (1994), Takeshita, K., Takashima, Y., Matsumoto,
S., Yamanaka.H .: J. Chem. Eng. Jpn., 28, 91 (1995), Takesh
ita, K., Ikeda, Y., Kumagai, M., Takashima, Y., Endo, Y., Hi
raoka, R .: International Conference on Adsorption in
Water Environment and Treatment Processes, Osaka, J
apan, November 1996, Nogami, M., Ninomiya, J., Ikeda,
Y., Wei.Y., Takashima, Y., Mason, C., Bush, R.: Internatio
nal Conference on Future Nuclear Systms, Global'97,
Yokohama, Japan, October 1997].

[0008] This method makes the treatment process of the liquid waste simpler than the solvent extraction method. However, together with the liquid waste or eluent passing through the column, CMP or CMPO impregnated in the SDB particles is used. There is a problem of elution. For this reason, repeated use of the adsorbent becomes difficult. Also, the eluted CMP or CMPO molecules have an adverse effect on the final treatment of waste. Therefore, a method for treating radioactive waste that does not have such a problem is desired.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a separation method capable of selectively separating a transuranium element from a radioactive waste liquid containing the transuranium element by using a chelating resin. Second, it is to provide a novel chelating resin used for this.

[0010]

This and other objects are achieved by the present invention described below. (1) Using a chelating resin having n-octyl (phenyl) -N, N-diisobutylcarbamoylmethylphosphine oxide as a functional group, selectively separating transuranium elements from radioactive waste liquid containing transuranium elements. And the separation method. (2) The chelate resin forms a salt of n-octyl (phenyl) phosphinyl-N, N-diisobutylcarbamoylmethanide by dehydrogenation of n-octyl (phenyl) -N, N-diisobutylcarbamoylmethylphosphine oxide. The method according to the above (1), wherein the salt is reacted with poly (chloromethylstyrene). (3) A chelate resin obtained by the separation method of (2).

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The chelate resin used in the present invention is a resin having n-octyl (phenyl) -N, N-diisobutylcarbamoylmethylphosphine oxide (CMPO) as a functional group. Using such a resin, it is possible to selectively separate the transuranium element from the radioactive waste liquid containing the transuranium element in particular. For this reason, since a waste liquid containing no transuranium element can be obtained, waste liquid treatment is facilitated. In particular, it is preferably used for the separation of actinoid elements, particularly transuranium elements, from radioactive waste liquids having low levels (low-level waste liquids and medium-level waste liquids). In addition, CM which is a functional group
PO coordinates with metal ions when collecting metal ions-
Since PO and -CO do not involve acid dissociation, they can be used for treating acidic high-level waste liquid discharged by the Purex process. Therefore, a lanthanoid element and / or an actinoid element can be selectively separated using this chelate resin.

As described above, in the present invention, since the treatment using the chelate resin is performed, the formation of the third phase by the conventional solvent extraction method using CMPO as the extracting agent, or the formation of C
CMP by chromatographic method using styrene-divinylbenzene copolymer particles impregnated with MPO as adsorbent
There is no elution of O and the processing operation is easy. In addition, the chelating resin can be used repeatedly.

The chelate resin of the present invention comprises a salt of n-octyl (phenyl) phosphinyl-N, N-diisobutylcarbamoylmethanide in which the methylene group in CMPO forms a carbanion to form a salt, and poly (chloromethylstyrene) And obtained by reacting As a salt, a sodium salt is preferably used, and as poly (chloromethylstyrene), specifically, poly [1- (4-chloromethylphenyl) ethylene] is used. A scheme using such a compound is shown below.

[0014]

Embedded image

Poly [1- (4-chloromethylphenyl)
[Ethylene] (CP) is formed by chloromethylation of polystyrene.

[0016] CMPO is converted to tetrahydrofuran (TH
N-octyl (phenyl) phosphinyl-N, N having a methylene group substituted by Na (i.e. sodium methanide) by dehydrogenation using a hydride such as NaH in a non-aqueous solvent such as F) Sodium salt of diisobutylcarbamoylmethanide (CMPO ^* )
To form a salt such as At this time, the ratio between CMPO and NaH is such that the molar ratio of CMPO / NaH is about 1/1, and the mixture is stirred and reacted at a temperature of about 15 to 35 ° C. for about 0.5 to 2 hours. .

Next, CP is added to the CMPO ^* obtained in a solution state, and the resulting mixture is heated at a temperature of about 30 to 50 ° C. for 30 to 60 ° C.
The reaction is carried out with stirring for about an hour. CMPO at this time
The ratio of ^* to CP is such that the molar ratio of CMPO ^* / CP is 3 to 5. Further, it is preferable that the CP contains divinylbenzene (DVB) as a cross-linking agent.
DVB is 2 to 10 wt% with respect to P. Due to the presence of DVB, particles with appropriately sized pores are formed,
The reactivity with metal ions can be increased.

In the present invention, it is preferable to use polystyrene containing DVB so that the content of DVB in the CP is within the above range. Such polystyrene is commercially available, and a commercially available product can be used. .

Thereafter, the solid substance is filtered and purified to obtain CMPO.
Is obtained as a chelating resin (CMPO-resin). The above reaction is performed in a nitrogen atmosphere.

The formation of the CMPO-resin can be confirmed by infrared absorption spectrum (IR) analysis, elemental analysis and the like.

In the CMPO resin, the substitution ratio of Cl in CP by CMPO is preferably 80% or more, and particularly preferably 100%. CMPO
Can be determined by elemental analysis.

Although the CMPO-resin of the present invention is a polystyrene resin, it is easy to obtain a resin material as a raw material and is advantageous in cost.

The CMPO resin of the present invention is used as a chelate resin for collecting metal ions. Metal ions to be collected include trivalent lanthanide ions such as Ce (III), Nd (III) and La (III), U (VI), Am (III), and Cm (III).
And the like. And such a metal ion collection effect becomes large in an acidic region (acid concentration of 1 to 5 M).

In particular, the transuranium element can be selectively separated from the radioactive waste liquid containing the transuranium element. It is particularly effective for selectively separating actinoid elements, especially transuranium elements, from non-high-level waste liquid such as low-level waste liquid and medium-level waste liquid. Such a waste liquid is a solution containing an actinoid element, Sr, Cs, Fe, and the like. Elements (Np, Pu, Am, Cm) can be separated. For this reason, the subsequent waste liquid treatment becomes easy.

Also, CMPO-resin does not decrease the coordination ability to metal ions even under acidic conditions, but rather improves the coordination ability, and is used for treating acidic high-level waste liquid discharged by the Purex process. It is expected to be possible. Such high level liquid waste contains HNO ₃ of 2 to 4 m. In addition, fission products (Se, R
b, Sr, Y, Zr, Mo, Tc, Ru, Rh, Pd,
Ag, Cd, Sn, Te, Cs, Ba, La, Ce, P
r, Nd, Pm, Sm, Eu, Gd), Np, practically the total amount of transplutonium elements, and up to 1% of uranium and plutonium result in high level waste. The actinoid elements at this time are specifically U, Np, Pu, Am, and Cm.

Therefore, lanthanoid elements and / or actinoid elements can be selectively adsorbed and removed from such high-level waste liquid, and transuranium elements such as Am and Cm can be removed.

The treatment using the chelate resin of the present invention may be a batch treatment or a continuous treatment using a column or the like. The treatment operation can be performed at room temperature (temperature of about 15 to 35 ° C.).

[0028]

The present invention will be specifically described below with reference to examples. Example 1 A CMPO-resin was synthesized. n-octyl (phenyl)
-N, N-diisobutylcarbamoylmethylphosphine oxide (CMPO: manufactured by Hokuko Chemical Co., Ltd.) and tetrahydrofuran (THF: manufactured by Kanto Chemical Co., Ltd.) were commercially available products. Sodium hydride (NaH: manufactured by Kanto Chemical Co.) was used after recrystallization from diethyl ester.

(1) Synthesis of poly [1- (4-chloromethylphenylethylene)] (CP) Reaction of polystyrene (including DVB as a crosslinking agent) with chloromethylethyl ether using tin (IV) chloride as a catalyst And synthesized.

(2) n-octyl (phenyl) phosphinyl-N, N-diisobutylcarbamoylmethanide.
Synthesis of sodium (CMPO ^* ) 8.15 g of CMPO was added to 0.48 g of NaH and 100 parts of THF.
The reaction was carried out at 30 ° C. for 1 hour in ml to synthesize. CMPO ^*
Was obtained as a THF solution.

(3) Synthesis of CMPO-resin CP (including 2 wt% DVB) was added to the above-mentioned CMPO ^* solution.
5.0 g was added and reacted at 40 ° C. with stirring for 48 hours. Thereafter, the solid was filtered, washed with water, and further washed with ethanol to obtain the desired product.

(4) Identification of CMPO-resin IR spectra of CP, CMPO and CMPO-resin were measured. FTIR-810 manufactured by Shimadzu by KBr tablet method
It measured in the wave number range of 4000-400 cm < ^-1 > using the 0 spectrophotometer. The results are shown in FIG.

In the IR spectrum of the CP shown in FIG.
An absorption shoulder is observed around 74 cm ⁻¹ , which is assigned to the characteristic peak of V _c-cl . However, this characteristic peak disappears in the IR spectrum of the CMPO-resin in FIG. This indicates that the Cl atom of the chloromethyl group in CMPO was replaced with CMPO ^* . further,
In FIG. 1B, characteristic peaks of C = O (1634 cm ^-1 ) and P = O (1184 cm ^-1 ) in CMPO are observed.
In the CMPO-resin of FIG. 1 (c), P = O is 1123 cm.
^The shift to ^-1 is observed. These results show that the CMPO-resin was obtained by the reaction between CP and CMPO ^* .

Example 2 Using the CMPO-resin synthesized in Example 1, adsorption experiments of U (VI) and Ce (III) were performed by a batch method.

Using UO ₂ (NO ₃ ) ₂ .6H ₂ O, [UO
₂ ^2+] = 1MHNO ₃ solution 50 ml, and Ce (NO ₃₎ containing 10.0mM using _{3 · 6H 2 O, [Ce} 3+] = 5.
50 ml of a 1 MHNO ₃ solution containing 0 mM was prepared.

0.1 g of the CMPO-resin was added to the UO ₂ ²⁺ solution, and 0.5 g of the CMPO-resin was added to the Ce ³⁺ solution, followed by shaking at 25 ° C. for 2 hours. At this time, at an appropriate time interval, the solution was sampled with a pipette in an amount of 1 ml at a time, and the metal ion concentration in the sample was measured. UO
_The ²²⁺ concentration was quantified by colorimetry and the Ce3 ⁺ concentration was quantified by inductively coupled plasma (ICP) emission spectroscopy. The UO ₂ ²⁺ concentration was measured using a Shimadzu spectrophotometer (UV-2400P) using Arsenazo III or H ₂ O ₂ as a color former.
It was determined by measuring the absorbance at 650 nm or 390 nm using C). For the ICP emission analysis, Optima 3000 manufactured by Perkin-Elmer Co. was used.

The distribution coefficient K _D (cm ³ / g) was calculated by the following equation (1). K _D = [(Ci−Ce) / Ce] × (V / W) (1) where Ci and Ce are the metal ion concentrations at the initial and equilibrium stages of the aqueous phase (M = mol / dm ³ ), respectively. Represents
V and W are respectively the volume of the CMPO-resin (cm ³ )
And weight (g).

FIG. 2 shows the change in the amount of adsorption over time for UO ₂ ^{2+ and} FIG. 3 for Ce ³⁺ .

[0039] Further, performs adsorption experiment instead of nitric acid concentration, and the acid concentration dependence of the K _D. FIG. 4 shows the results.

As is clear from FIGS. 2 and 3, U
Adsorption equilibrium is reached within 20 minutes in both O ₂ ²⁺ and Ce ³⁺ systems. At equilibrium, the amount of adsorption on CMPO-resin is UO ₂ ²⁺ = 2.7 × 10 ^-3 mol / g, Ce ³⁺ =
It is 5.4 × 10 ^-5 mol / g.

As is apparent from FIG. 4, HNO ₃
Over the entire concentration range of 10 to K _D of UO ₂ ²⁺ and Ce ³⁺
A difference of ^two orders is observed. Thus, UO ₂ ²⁺ is Ce
^Shows selectivity higher than ³⁺ . In addition, the acid concentration dependence of Ce ³⁺ is relatively small, and it can be seen that it adsorbs even in 1 MHNO ₃ . The result is that at 25 ° C. the HNO ₃ aqueous solution
The extraction ratio of U (VI) and Am (III) in an n-dodecane solution containing M CMPO and 1.2 M tributyl phosphate is very similar to the nitric acid concentration dependence of the partition ratio (D). In this case, the D of Am (III) and U (IV) is 1～10,10 a ^{2-10 3} in the region of each of nitric acid concentration 0.1~6M [Schulz, WW, Horwitz, EP: Sep.Sci. Technol., 23,11
91 (1988)].

Since the chemical properties of Ce (III) are similar to the chemical properties of Am (III), the adsorptivity of CMPO-resin to actinide ions depends on the solvent extraction system CMPO-resin.
Is expected to be similar to the extraction capacity of Thus, it can be seen that the CMPO-resin can be applied to the treatment of liquid radioactive waste containing transuranium elements.

[0043]

According to the present invention, the transuranium element can be selectively separated from the radioactive waste liquid containing the transuranium element.

[Brief description of the drawings]

FIG. 1 shows an IR spectrum of poly [1- (4-chloromethylphenyl) ethylene] (CP) (a) and an IR spectrum of n-octyl (phenyl) -N, N-diisobutylcarbamoylmethylphosphine oxide (CMPO). (B) and IR spectrum of CMPO-resin (c)
FIG.

FIG. 2 is a graph showing the change over time in the amount of adsorption of U (VI) on a CMPO-resin.

FIG. 3 is a graph showing the change over time in the amount of Ce (III) adsorbed on CMPO-resin.

FIG. 4 is a graph showing the nitric acid concentration dependence of the adsorption of U (VI) and Ce (III) on CMPO-resin.

Claims (3)

[Claims] 1. Using a chelating resin having n-octyl (phenyl) -N, N-diisobutylcarbamoylmethylphosphine oxide as a functional group, selectively separating transuranium elements from radioactive waste liquid containing transuranium elements. A separation method characterized by the above-mentioned. 2. The chelating resin according to claim 1, wherein the salt of n-octyl (phenyl) phosphinyl-N, N-diisobutylcarbamoylmethanide is obtained by dehydrogenation of n-octyl (phenyl) -N, N-diisobutylcarbamoylmethylphosphine oxide. 2. The method according to claim 1, wherein the salt is formed and reacted with poly (chloromethylstyrene). 3. A chelate resin obtained by the separation method according to claim 2.