JP5651433B2 - Waste ion exchange resin treatment method and treatment apparatus - Google Patents

Description

  The present invention relates to a processing method and a processing apparatus for waste ion exchange resin.

  At the nuclear facility, the chemical analysis room conducts purification of condensate (turbine cooling water for generators), radioactivity analysis of reactor water, and analysis of chemical components. A large amount of granular ion exchange resin and powder ion exchange resin are used for the purification of these condensate and chemical analysis wastewater. The granular ion exchange resin and the powder ion exchange resin are subjected to a regeneration process, but the processing capacity is reduced. Therefore, the regeneration process is performed to some extent and then discarded.

  These waste ion exchange resins are directly solidified with cement, or mixed and kneaded in an extruder with heat-melted chlorinated polyethylene and stored as pellet waste. It is most suitable to solidify with cement to store and dispose of the stored pellet waste in a more stable form.

  On the other hand, when solidifying a waste ion exchange resin, generally, the waste ion exchange resin is generally rendered harmless and, if necessary, reduced in volume and then used for cement solidification.

  For example, Patent Document 1 discloses disabling an ion exchange group that is an adsorption site of a waste ion exchange resin under hydrothermal conditions. Patent Document 2 discloses that a waste ion exchange resin is held at a pressure equal to or higher than the saturated vapor pressure of water and a temperature of 200 ° C. or less, and an ion exchange group that captures metal ions from the waste ion exchange resin is removed. Has been. Further, in Patent Document 3, after drying the waste ion exchange resin, it is thermally decomposed in a low-pressure oxygen atmosphere, and at the same time, the oxygen plasma is heated to promote the oxidation reaction between the decomposition gas and high-temperature oxygen. In addition, it is disclosed that the gas generated during pyrolytic oxidation is rendered harmless by chemical treatment.

  However, even when the waste ion exchange resin is detoxified as described above, particularly when the waste ion exchange resin contains a weakly basic ion exchange resin, when the waste ion exchange resin is cemented, the waste ion exchange resin There was a problem that the exchange resin may swell and damage the solidified body.

JP 2009-162646 A Japanese Patent Laid-Open No. 11-23793 JP 2001-305287 A

  In the present invention, particularly when a waste ion exchange resin containing a used weak base ion exchange resin (weak base anion exchange resin) in a nuclear facility is cemented and treated, the waste ion exchange resin is swollen. It is intended to prevent and stably dispose of waste ion exchange resin without damaging the cement solidified body.

One aspect of the present invention is a method for treating a waste ion exchange resin containing a weakly basic ion exchange resin, the waste ion exchange resin comprising a monovalent alkali in a content of 26% by mass to 38% by mass. While immersed in an alkaline aqueous solution and heated and maintained at 90 ° C. to 100 ° C., the amino group of the weakly basic ion exchange resin in the waste ion exchange resin is decomposed and the decomposition product is released out of the system. And a step of solidifying the waste ion exchange resin with cement, and a method for treating the waste ion exchange resin.

  According to the present invention, when a waste ion exchange resin containing a weakly basic ion exchange resin used in a nuclear facility is cemented and treated, the waste ion exchange resin is prevented from swelling, and the cement solidified body is obtained. It is possible to perform a stable disposal process of the waste ion exchange resin without damaging the resin.

It is a schematic block diagram which shows the processing apparatus of the waste ion exchange resin of embodiment.

  Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 1 is a diagram illustrating a schematic configuration of a radioactive liquid waste treatment apparatus according to the present embodiment.
A waste ion exchange resin treatment apparatus 10 shown in FIG. 1 is connected to a reaction vessel 11 containing an alkaline aqueous solution S, a reaction vessel 11 and a pipe 21, and waste ion exchange resin treated in the reaction vessel 11. A dryer 12 for drying as necessary, a pulverizer 13 connected to the dryer 12 via a pipe 22 and pulverizing the waste ion exchange resin dried by the dryer 12 as necessary; It has a solidified body preparation device 14 that is connected to the pulverizer 13 via a pipe 23 and solidifies the pulverized waste ion exchange resin obtained by the pulverizer 13 into cement.

  A heater 111 for heating the alkaline aqueous solution S in the reaction vessel 11 is provided on the outer periphery of the reaction vessel 11, and a stirrer 112 is installed in the lower portion of the reaction vessel 11.

  The reaction vessel 11 and the solidified body preparation device 14 constituting the processing device 10 are made of a material having high corrosion resistance such as stainless steel. As the dryer 12, a general-purpose one such as a heater-type dryer can be used. As the pulverizer 13, a general-purpose one such as a rotor-type pulverizer can be used. As the solidified body manufacturing apparatus 14, an in-drum system or an out-drum system can be used.

  Next, the radioactive waste liquid processing method using the radioactive waste liquid processing apparatus 10 shown in FIG. 1 will be described.

  First, the alkaline aqueous solution S is put into the reaction vessel 11 in the processing apparatus 10 of FIG. 1 as described above. Next, a waste ion exchange resin containing a weakly basic ion exchange resin used in, for example, a nuclear facility is placed in the reaction vessel 11 and immersed in the alkaline aqueous solution S. The waste ion exchange resin is granulated in advance using a predetermined resin composition to form pellets or particles. After preparing the pellet or particle waste ion exchange resin, the reaction vessel 11 is processed in the same manner as described above. It can be immersed in the alkaline aqueous solution S inside.

  Waste ion exchange resins containing weakly basic ion exchange resins contain amino groups, so in the state as they are, amino groups are liberated to generate amine gas, or when ammonia gas is generated by reacting with air There is. Therefore, when the waste ion exchange resin is directly subjected to cement solidification to produce a cement solidified body, the amine gas and ammonia gas are generated in the cement solidified body, so that the cement solidified body swells and cement solidified body. Could be damaged.

  However, in this embodiment, the waste ion exchange resin is immersed in the alkaline aqueous solution in the reaction vessel 11 before being subjected to cement solidification. Then, the amino group of the waste ion exchange resin, that is, the weakly basic ion exchange resin contained therein, is decomposed by the alkali in the alkaline aqueous solution S. For example, when sodium hydroxide is used, the amino group is decomposed to become amine or ammonia and released out of the system. Accordingly, even when the cement is subsequently solidified, amine gas and ammonia gas are not generated in the solidified body. As a result, the cement solidified body can be provided stably without damaging the cement solidified body, and the waste ion exchange resin can be disposed of safely and reliably.

  The aqueous alkali solution S preferably contains a monovalent alkali. Since monovalent alkali is a strong base, the amino group can be decomposed more efficiently. That is, the amino group can be decomposed in a shorter time. Specific examples include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like, and sodium hydroxide is particularly preferable.

  In this case, the content of the monovalent alkali in the alkaline aqueous solution S is preferably 25% by mass to 38% by mass. Thereby, the amino group of the waste ion exchange resin can be decomposed more efficiently. When the monovalent alkali content is less than 25% by mass, the efficiency of amino group decomposition by alkali may not be sufficiently improved. On the other hand, even if the content of monovalent alkali exceeds 38% by mass, the decomposition efficiency of amino groups can no longer be improved, and the reaction vessel 11 may be corroded.

  Moreover, it is preferable that the temperature of alkaline aqueous solution S is the range of 90 to 100 degreeC. Also in this case, the amino group of the waste ion exchange resin can be decomposed more efficiently. If the temperature of the aqueous alkaline solution S is less than 90 ° C., the efficiency of amino group decomposition by alkali may not be sufficiently obtained. On the other hand, if the temperature of the alkaline aqueous solution S exceeds 100 ° C., the reaction vessel 11 may be corroded.

  In addition, when maintaining the aqueous alkali solution S in the above temperature range, the heater 111 provided in the outer peripheral part of the reaction container 11 is used. Further, when the waste ion exchange resin is treated with the alkaline aqueous solution S, the stirrer 112 provided at the lower part of the reaction vessel 11 is agitated at a rotational speed of, for example, several tens to several hundreds of rpm, as necessary. The reaction between the amino group of the exchange resin and the alkaline aqueous solution is promoted.

  Next, as described above, the waste ion exchange resin that has been treated in the reaction vessel 11 is introduced into the dryer 12 via the pipe 21. And the water | moisture content adhering when it immersed in the alkaline aqueous solution S in the reaction container 11 or the water | moisture content produced by reaction of an amino group and an alkali is dried and removed. In this case, water in the waste ion exchange resin is removed, and as a result, the waste ion exchange resin is reduced in volume before being used for cement solidification.

  In addition, the drying temperature in the dryer 12 can be 100 degrees C or less, for example. In order to perform the drying process in a short time, it is preferable to dry at a high temperature. However, since the drying process can be performed at room temperature, the drying temperature is 100 ° C. or less from the viewpoint of shortening the drying time and saving energy. It is preferable that

  Next, the waste ion exchange resin after the drying treatment is introduced into the pulverizer 13 through the pipe 22 and pulverized to an appropriate size. Next, the pulverized material thus obtained is introduced into the solidified body producing apparatus 14 via the pipe 23 and mixed with the cement similarly introduced into the solidified body producing apparatus 14 to form a cement solidified body.

  The cement used is preferably, for example, alumina cement, blast furnace slag cement, fly ash cement, and Portland cement. Since these cement materials are easily available, are inexpensive, and are stable to seawater and chemical substances, they are suitable as cement materials for solidifying and stabilizing radioactive drainage as in this embodiment. Yes. In particular, alumina cement is made of bauxite and limestone, which are raw materials of aluminum, and is a cement containing aluminum oxide, and exhibits high strength immediately after kneading, and therefore has excellent ion confinement properties.

  Additives such as an aggregate, a fluidizing agent, and a coagulation reaction accelerator can be blended with the above-described cement as necessary.

  The cement kneading water is generally ion-exchanged water when solidifying waste ion-exchange resin from nuclear facilities, but tap water or waste water may also be used. .

  As described above, according to the present embodiment, the waste ion exchange resin containing the weak basic ion exchange resin is immersed in an aqueous alkali solution, and the amino group in the waste ion exchange resin is decomposed with an alkali to solidify the cement. Therefore, amine gas and ammonia gas are not generated in the solidified body. As a result, the cement solidified body can be provided stably without damaging the cement solidified body, and the waste ion exchange resin can be disposed of safely and reliably.

  In the following examples, in order to confirm the effect of the present invention, the ion exchange resin was immersed in an alkaline aqueous solution, and then it was examined whether amine gas and / or ammonia gas was generated.

Example 1
First, 100 g of a 25% by mass aqueous sodium hydroxide solution was placed in a 300 cc conical beaker, and the conical beaker containing the sodium hydroxide solution was placed on a hot stirrer. Then, after maintaining the temperature of the sodium hydroxide aqueous solution at a temperature of 90 ° C. to 100 ° C. with a hot stirrer, 10 g of a granular weakly basic anion exchange resin (Diaion EMA200) is put, and the top of the conical beaker is covered with water at 100 rpm. The aqueous sodium oxide solution was stirred.

  Then, the gas detector was arrange | positioned in the upper cover vicinity of the conical beaker, and the density | concentration detection of the produced | generated gas was implemented. As a result, it was confirmed that about 1000 ppm of amine gas and ammonia gas were generated at the beginning of the measurement, but after several minutes to several tens of minutes, amine gas, ammonia gas, and the like were not detected.

  Therefore, even when the granular anion exchange resin treated in this way is appropriately dried and pulverized and used for cement solidification, the cement solidified body is damaged because amine gas or the like is not generated in the cement solidified body. It can be seen that the cement solidified body can be provided stably. Therefore, when such a granular anion exchange resin is a waste ion exchange resin, it turns out that the disposal process can be performed safely and reliably.

(Example 2)
In Example 1, the experiment was performed in the same manner as in Example 1 except that the concentration of the sodium hydroxide aqueous solution was increased from 25% by mass to 38% by mass. As a result, it was confirmed that about 1000 ppm of amine gas and ammonia gas were generated in the vicinity of the upper lid of the conical beaker at the initial stage of the measurement, but after several minutes to several tens of minutes. Amine gas and ammonia gas were no longer detected.

  Therefore, even when the granular anion exchange resin treated in this way is appropriately dried and pulverized and used for cement solidification, the cement solidified body is damaged because amine gas or the like is not generated in the cement solidified body. It can be seen that the cement solidified body can be provided stably. Therefore, when such a granular anion exchange resin is a waste ion exchange resin, it turns out that the disposal process can be performed safely and reliably.

  As mentioned above, although several embodiment of this invention was described, these embodiment was posted as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 Processing apparatus of waste ion exchange resin 11 Reaction container 111 Heater 112 Stirrer 12 Dryer 13 Crusher 14 Solidified body preparation apparatus 21, 22, 23 Piping

Claims (4)

A method for treating waste ion exchange resin including weakly basic ion exchange resin,
The waste ion exchange resin is immersed in an aqueous alkali solution containing a monovalent alkali in a content of 26% by mass to 38% by mass , heated to 90 ° C. to 100 ° C., and retained. Decomposing the amino group of the weakly basic ion exchange resin therein to release the decomposition product out of the system;
Cementing the waste ion exchange resin; and
A process for treating a waste ion exchange resin, comprising: 2. The treatment of waste ion exchange resin according to claim 1 , wherein the cement used for cement solidification is at least one selected from the group consisting of Portland cement, blast furnace cement, fly ash cement, and alumina cement. Method. The waste ion exchange resin treatment method according to claim 1 or 2 , wherein the waste ion exchange resin is a pellet-like or granular exchange resin obtained by granulating a predetermined resin composition as a binder. . A waste ion exchange resin treatment apparatus including a weakly basic ion exchange resin,
The waste ion exchange resin is immersed in an aqueous alkali solution containing a monovalent alkali in a content of 26% by mass to 38% by mass , heated to 90 ° C. to 100 ° C., and retained. A reaction vessel for decomposing amino groups of the weakly basic ion exchange resin therein,
A solidified body preparation apparatus for cementing the waste ion exchange resin;
An apparatus for treating waste ion exchange resin, comprising:

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