JPS58146899A - Method of processing radioactive ion exchange resin waste - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating waste ion exchange resin containing medium to low levels of radioactive substances.

There is no suitable treatment method for waste ion exchange resin generated from nuclear power plants and facilities that handle radioactive materials, so they are stored in tanks on-site or in drums, but the increase in storage volume is This is an unavoidable and important problem, and there is an urgent need to develop a safe treatment method.

Methods for treating this resin include incineration, acid digestion, and catalytic oxidation using hydrogen peroxide, but all of these methods have problems such as corrosion of the structural materials of treatment facilities, exhaust gas treatment, and reduction ratio. be. As a technique similar to this invention,
There is a wet oxidation method (Zinpro method) used to treat high-concentration organic wastewater, but this method tends to stop oxidation with organic acids. Therefore, it is also known to add a catalyst (such as Cu ions) to improve this drawback and improve the degree of oxidation. However, the possibility and usefulness of oxidizing ion exchange resins by these methods are unknown. Furthermore, the conventional method involves continuously feeding a large amount of water and organic matter into the oxidation reactor, which has the disadvantage of producing a large amount of waste water.

This invention provides a method for safely and energy-saving oxidation loss treatment of waste ion-exchange resin used for treating radioactive materials.・The aqueous catalyst solution is repeatedly used, and the waste resin is It is characterized by the fact that it is charged with almost no moisture and is completely oxidized to carbon dioxide gas in a batch process.

In the incineration method, many problems remain unsolved, such as corrosion of materials that can withstand high temperatures and materials of equipment used to separate and remove SOx and NOx generated by combustion of the resin from waste gas.

In addition, in the acid decomposition method, the resin is decomposed using strong acid at high temperatures, so corrosion of major equipment such as the decomposition tank is a major problem, and the exhaust gas treatment process also requires complicated equipment, so it is not easily put into practical use. . According to this invention, the organic matter in the resin is completely oxidized to carbon dioxide gas, so the weight loss ratio is excellent,
In addition, S in the exchange group S and N in the resin is 804--
Since N remains in the solution as NH4+, it remains in the solution or becomes NH3, which is easy to process, so SOx is present in the exhaust gas.

Almost no NOx exists. Furthermore, radioactive substances exist in solution and are hardly contained in exhaust gas. Therefore, the exhaust gas treatment process may be a simple device that prevents only the leakage of radioactive materials due to entrainment of some droplets.

In addition, the pH of the solution after the oxidation reaction is /~3, and although there are some problems with the material of the reactor, 0aCO3, Ca(OH
)z, Na0I ('z) is added and reacted, there is no effect on oxidative decomposition until the pH after the reaction is 5, and material selection is easy.

The method of this invention will be explained in detail below.

The ion exchange resins to be silyolyzed by the method of this invention include both cation exchange resins and anion exchange resins. These are mainly based on styrene and divinylbenzene copolymers, into which cation exchange groups and anion exchange groups have been introduced, but they are not limited to this, and those with other structures can also be decomposed. be.

Cation exchange resins can decompose metal ions and radionuclides in addition to H-type and Na-type in a state in which they are ion-exchanged or adsorbed.

In addition to the OH type, anion exchange resins are OL- and 5O4-.

Furthermore, it is possible to decompose radioactive anions in a state in which they are ion-exchanged or adsorbed.

Cation and anion exchange resins can be used alone or in combination.

Furthermore, although these resins are in the form of particles or powder, it is advantageous from the point of view of the reaction rate for large particle size ion exchange resins to be treated by pulverizing the core resin to 10θμ or less. This effect is particularly remarkable in cation exchange resins. The method of this invention is characterized by the use of metal ions as catalysts. Metal ions include Ou and Ou.

One or more of co++, Fe red, Fe+++, Pd+10, and CE+10 or +12 or more are used in combination. Especially Cu or P
d++, and combinations of both are preferred.

The concentration of metal ions is within the range of / to /θθppm, preferably / to /θθppm.

The reaction temperature is /θθ to 3θθ°C, preferably 790°C to SO0°C.

The partial pressure of oxygen is 3 to 30 kg7crao, and pure oxygen or air can be used as the oxygen.

The decomposition reactor is of a stirring type and a second type as shown in Figure 1.
A bubble column system as shown in the figure is preferred.

An aqueous solution containing metal ions is kept in a reactor, and after adding waste ion exchange resin, it is sealed, heated to a predetermined temperature, pressurized, and oxygenated to a predetermined oxygen partial pressure. While feeding, exhaust gas is removed from the pulp 2, the reactor is maintained at a constant pressure, and the reaction is allowed to proceed for a period of time with stirring.

Even if some unreacted organic matter remains in the solution, this reaction is repeated by heating, pressurizing, and oxygen supply until the aqueous solution in the reactor is almost saturated with the ash in the resin. Continue oxidative decomposition for several hours without adding
Completely oxidizes organic matter.

Finally, the waste liquid is evaporated to dryness to produce reduced waste.

Further, even if an aqueous solution containing metal ions is used several times/θ times, the activity of the catalyst does not decrease, so it can be used repeatedly until it is saturated with ash and the like.

Although the solution can be neutralized with an alkaline substance such as ca(OH)z and evaporated to dryness, the weight loss ratio will be small.

In order to increase the weight loss ratio, H2SO4 in the solution can be removed by ion dialysis or the like and then evaporated to dryness.

This invention can repeatedly use an aqueous solution of metal ions when wet oxidizing waste ion exchange resin at high temperature and high pressure, resulting in a large weight loss ratio, and only carbon dioxide and water are released in the exhaust gas. SOx and NOx are not emitted. Therefore, complicated processing steps are not required, materials can be easily selected, and great economic benefits can be obtained.

In other words, this invention provides a method for treating waste ion exchange resin stored on facility grounds, for which no suitable treatment method has been available up to now. It is also possible to develop this technology into combustible solid waste treatment.

The method of the present invention will be specifically explained below using examples.

Example/ Put 2 somt of water into an autoclave with an internal volume/θomt shown in FIG.
(Sθθppm as Cu) and Amberlite■
■Add ㇠-7, 2θB-H type dry product θ309, and add oxygen 7
kg/dG was enclosed. The autoclave was heated until it reached 23θ°C and stirring was started.

After / hour stirring was stopped and the internal gas was released after cooling to room temperature.

The gas was measured with a Tregel [F] detector tube, but S
Ox was not detected (detection sensitivity, 5 ppm or less).

After opening the lid, the reaction solution was clear and free of solid matter. When the residual organic matter in the solution was measured using a total organic carbon analyzer, the total organic carbon (Toe) was 2/ppm.

This corresponds to 97 Jwt as a decomposition rate of organic carbon.

Example 2 Amberly) IR-/jθB-Na type dry product θs
I used oy. Decomposition was carried out in the same manner as in Example/in all other respects.

The results are shown in Table 1.

Example 3 Amberlite IRA-G θ0-OH type dry product 0j0
2 was used. Everything else is the same as Example/, but NOx in the released gas is detected using a Tregel detector tube (detection sensitivity θ/
ppm). The results are shown in Table 1.

Example Guamberlite IRA-10θ-at type dry product 0! ;
Of was used. Decomposition was carried out in the same manner as in Example/in all other respects. The results are shown in Table 1.

Example j Amberlite l ILA-g θθ-OH type θ! 37
and Amberlite IR-/2θB-H type 0.232
(all dried products) were used. Otherwise, the decomposition was carried out in the same manner as in Example. The results are shown in the first page.

Water S was placed in a bubble column reactor with an internal volume of
Insert t, 011804 ・jHzo 9g, 2 f
was added, Amberlite/2θB-H type root (dry product) was added, and the temperature was heated until it reached 23θ℃.
Maintain the total pressure at 37kg/ff1G.

Oxygen was charged through Pulp J at a flow rate of 100 L/H, and the reaction was carried out for 7 hours while exhaust gas was released through Pulp B.

The results are shown in Table 2.

Example 7 Amberlite I R-/, 20B-H type was ground to an average particle size of s41μ, and Koθθt (dry product) was added. Decomposition was carried out in the same manner as in Example 6 except for the above.

The results are shown in Table 1.

An improvement in the decomposition rate was observed compared to the granular resin of Example B.

Example g Amberlite IRA-&θθ-0) type 1 was converted into 2θθ7(
(dried product) was added.

Otherwise, disassembly was carried out in the same manner as in Example B. The results are shown in Table 2.

Example (Taanbarai) IRA-&θθ-OH type was pulverized and 10θ7 (dry product) was charged with an average particle size of j/μ. Otherwise, disassembly was carried out in the same manner as in Example B. The results are shown in Table 1. Almost the same decomposition rate was shown as in the example.

Example/θ Amberlite I R was placed in the autoclave shown in Figure 1.
-/, 20 B-H type 0! ; Of was added, 0.21% of calcium hydroxide was added, and decomposition was carried out in the same manner as in Example.

The TOC after the reaction was 23 ppm, indicating a decomposition rate comparable to that of Example 1 when no calcium hydroxide was added.

The pH of the solution after the reaction was 0.

Example // Amberlite IRA was placed in the autoclave shown in Figure 1.
-&0O-OH type Oj Off, cuSO4・3H
zOcg9/li, water, 23; θml, oxygen 7 kg
/crA G was sealed, and reaction was performed at -23θ°C for 5 hours, and the TOC concentration of the solution after the reaction was measured. Next, a new resin θSOt and 7 kg/d () of oxygen were added, and 2
A second reaction was carried out at 3θ°C for S time. The reaction was repeated/times in the same manner. The results are shown in Table 3. Third
The residual TOO after the subsequent reactions remained essentially constant, indicating that the activity of the catalyst did not deteriorate during use.

Table 3 Repeated experiment results Ion exchange resin: IRA-4'0θ, OH type, θs
Example 2/Amberlite Il' was placed in the autoclave shown in Figure 1
LA-da θ0-OH type θSOt was added, 2θ mmol of each metal salt shown in Table 9 was added, and the reaction was carried out in the same manner as in Example. Too in the solution after reaction and N in exhaust gas
Ox was measured. The results are shown in Table 1.

Catalyst concentration: 2θ mmol/, 2j OmL Example/3 Place amber lye in the autoclave shown in Figure 1) rR
, -/100-OH type θS02 was added, and the amount of copper sulfate, which is the f1 catalyst, was varied. The reaction was carried out in the same manner as in Example/in all other respects. The results are shown in Table 5.

Catalyst CuSO4・5H20

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an autoclave equipped with a stirrer used in the Examples, and FIG. 1 is a longitudinal sectional view of a bubble column type pressurized reactor similarly used in the Examples. Figure 1 Figure 1 / Gas population valve / Reactor 2 Gas outlet valve 2 Upper flange 3tj, sampling valve 3 Lower flange stirrer Gas distribution plate j Pressure meter 5 Oxygen-containing gas population valve k Safety valve B Oxygen-containing gas outlet valve 7 electric furnace
7 Autoclave and electric furnace for liquid discharge valve? thermometer
9 Electric furnace/θ thermometer//Safety valve Applicant Toyo Engineering Co., Ltd. Agent Dai
Zu Mingfeng Figure 1 Figure 1 Procedures Amendment (spontaneous) 1. Indication of the case: 1982 Patent Application No. 28739 2. Name of the invention: Method for treating radioactive waste ion exchange resin 3. Case of the person making the amendment Relationship with Patent applicant representative Masao Enoi 4, agent 5, no date of amendment order (voluntary amendment) Column 1 for detailed explanation of the invention in the specification! ” he corrected. 8. No list of attached documents

Claims (1)

[Scope of Claims] ■ Waste ion exchange resin containing medium to low level radioactive substances is poured into water in which metal ions are dissolved, and this suspension is heated to 796-386°C and pressurized to contain oxygen. After introducing gas and adjusting the oxygen partial pressure to a range of 3 to 3θkg/ctAo to moderately oxidize the resin and repeat this operation,
A method for reducing the amount of radioactive waste ion exchange resin characterized by continuing oxidative decomposition without introducing new waste ion exchange resin to completely oxidize and decompose the organic matter, and then evaporating the remaining salt aqueous solution to dryness. . Q Metal ions are Cu+, Ou'', co'', Fe++'
, F'e''60+10Pd,Ce are present as metal ions in a concentration range of /~koθoo ppm. ■ Reaction liquid after oxidative decomposition. As long as the PH of does not exceed S,
Claim 1 or the method according to claim 1, wherein a substance that neutralizes the acid is added. (2) The method according to claim 1 or 2, wherein the return water ion exchange resin or a mixture of resins containing the resin is pulverized to a body of 0 μm or less.