JP2006313078A - Solidification method for organic waste liquid and solidification equipment of organic waste liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To convert organic waste liquid including radioactive materials to a solid proper for stable storage for a long term. <P>SOLUTION: To organic waste liquid 1 of tributyl phosphate and dodecane as main components and including radioactive materials, an epoxy base resin 2 and a hardening agent 3 are added and mixed so that the epoxy resin is crosslinked in the organic waste liquid 1 and the whole organic waste liquid is solidified. The epoxy base resin 2 and the hardening agent 3 are a combination to promote a crosslinking reaction at ambient temperature. As the hardening reaction causes heating, the inside of the solid shows temperature rise. The temperature in this situation should be controlled not to rise over the boiling point or the flash point of the organic waste liquid 1. An optimum epoxy base resin 2 for it is bisphenol A type and a hardening agent 3 for it is alicyclic amine. The organic waste liquid 1 is put in a drum 5 and the liquid epoxy base resin 2 and the hardening agent 3 are added. Stirring is continued until the crosslinking reaction proceeds to some extent and the organic waste liquid 1 and the resin are not separated. After completion of solidification, the drum 5 is sealed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic waste liquid solidification processing method and an organic waste liquid solidification processing apparatus including at least a radioactive substance, and in particular, nuclear energy such as a beneficiation / smelting facility for radioactive materials such as uranium and thorium, a spent nuclear fuel reprocessing facility, etc. The present invention relates to a method for solidifying organic waste liquid generated in related facilities or research facilities in the field of nuclear energy or radiochemistry.

  In a natural uranium refining facility, uranium is purified by a solvent extraction method using organic reagents such as tributyl phosphate.

  In the spent nuclear fuel reprocessing facility, an organic solution in which tributyl phosphate is dissolved in dodecane is used as an extraction reagent in order to recover uranium and plutonium.

Most of the organic solutions used in these facilities are reused after purification.
Along with that, organic waste liquid is also generated.

  In the refining facility and reprocessing facility, metal ions contained in solutions from various processes are quantitatively analyzed as process analysis. In many cases, separation is performed using an organic solvent as a pretreatment for analysis, and an organic waste liquid is also generated from the process analysis step.

  Among such organic waste liquids, the treatable organic waste liquid is reduced and stabilized by incineration or heat treatment, and other organic waste liquids are stored and stored.

  At nuclear-related research facilities, radiochemical research facilities, and other research facilities that use radioisotopes, various types of organic waste liquids are generated from research activities. Many of them are stored in the facility.

  When the organic waste liquid is stored and stored as a liquid, measures are taken such as doubling the container and providing a weir in case of leakage.

  If this organic waste liquid is stored in a gelled state instead of a liquid, a method using an oil gelling agent has been proposed, assuming that the possibility of leakage of the organic waste liquid can be virtually ignored (for example, Patent Document 1). reference).

As the oil gelling agent, an oil gelling agent mainly composed of 12-hydroxystearic acid is known. 12-hydroxystearic acid contains a carboxylic acid, where a dimer is formed. There is a hydroxyl group at the 12-position, and this hydroxyl group forms a hydrogen bond with the carboxylic acid dimer. In this way, when the oil gelling agent is dissolved, the organic waste liquid is solidified.
Japanese Patent Laid-Open No. 10-123291 (page 4 FIG. 2)

  When the organic waste liquid containing the radioactive substance is gelled, the organic waste liquid is put in a drum can and heated, and an oil gelling agent is added and dissolved. The temperature at this time must be carefully set so as not to exceed the flash point of the organic waste liquid.

  When an organic waste liquid with a low flash point is gelled, the organic waste liquid may be heated to a temperature higher than the flash point. In that case, take measures such as making the gelling device an explosion-proof structure. There is a need.

  As in the above conventional example, the organic waste liquid solidified with the oil gelling agent is plasticized when the room temperature rises during storage and storage, and in some cases, it may be fluidized again.

  As a countermeasure, it is required to strictly control the temperature during storage and storage, and there is a problem that extra manpower, energy and cost are required.

  The subject of this invention is providing the solidification processing method of the organic solution which converts the organic waste liquid containing a radioactive substance into the solidified body suitable for long-term stable storage.

  In order to solve the above problems, the present invention provides a method for solidifying an organic solution containing at least a harmful substance such as a radioactive substance, and solidifying the organic solution by crosslinking a polymer material in an organic waste liquid. Propose.

  According to the solidification method of the organic waste liquid of the present invention, the organic waste liquid can be solidified while completely eliminating the possibility of fire and volatilization of the radionuclide. The solidified body has a stable shape even when the temperature rises during storage, and is suitable for long-term storage.

  In the present invention, the organic solution is solidified by crosslinking a polymer material such as an epoxy resin in the organic waste liquid.

  The epoxy resin uses a two-component blend system of an epoxy main agent and a curing agent. A liquid epoxy main agent and a curing agent are added to the organic waste liquid, and the crosslinking reaction proceeds while stirring to cure the entire organic waste liquid.

  The organic solution may or may not be compatible with the epoxy resin. It is clear that those that are compatible can produce a uniform solidified body.

  The inventors have discovered that even in an organic solution that is not compatible at first, when the crosslinking of the epoxy resin proceeds while continuing stirring, a uniform solidified body can be finally obtained. In this state, it is presumed that the organic solution component is taken into the crosslinked structure of the epoxy resin. Based on this discovery, the organic waste liquid solidification method of the present invention was created.

  The temperature condition when the crosslinking reaction proceeds is room temperature or higher. In the case of crosslinking at room temperature, a combination of a room temperature curing epoxy main agent and a curing agent is selected.

  When crosslinking at a temperature higher than room temperature, a combination of an epoxy resin and a curing agent that is crosslinked at a temperature not exceeding the boiling point or flash point of the organic waste liquid is selected.

  A typical example of an epoxy resin that cures at room temperature or a temperature slightly higher than room temperature is a combination of a bisphenol A type epoxy main agent and an aliphatic amine or alicyclic amine.

  A typical blending ratio is such that the amount of the bisphenol A type epoxy base agent added to the organic waste liquid is 30% by volume or more. This volume% is based on the result of the inventors' diligent examination and searching for conditions for producing a stable solidified body.

  Further, when a curing agent of an aliphatic amine or an alicyclic amine is added so that the amount of active hydrogen is substantially equal to the epoxy group in the main agent, a stable solidified body is finally obtained.

  It is a fact found by the present inventors that when an epoxy main agent or a curing agent is added to an organic waste liquid, it becomes uniform as crosslinking proceeds even if it is not uniform with the organic waste liquid at first.

  In the solidification process, it is important to continue stirring until the organic waste liquid and the epoxy resin do not phase separate.

  When the epoxy resin is crosslinked in the vicinity of the boiling point or flash point of the organic waste liquid, the possibility of the boiling point or flash point lowering than expected due to the influence of variations in the organic waste liquid components should also be considered.

  In order to prevent ignition, a flame retardant epoxy base material containing halogen is used. If a flame retardant such as aluminum hydroxide that prevents combustion of organic waste liquid is added to the mixed system of the organic waste liquid, the epoxy main agent, and the curing agent, the risk of fire during the solidification process can be reliably reduced.

  Since the epoxy resin is a thermosetting resin, it does not fluidize even if the temperature of the organic waste liquid solids increases during storage. Therefore, the solidified body is stable even when an environmental change during storage is assumed.

  Next, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a flowchart showing a processing procedure of a method for solidifying an organic waste liquid containing a radioactive substance according to the present invention.

  Example 1 is a method for solidifying an organic waste liquid mainly composed of tributyl phosphoric acid, which is a reprocessing solvent, and dodecane, using a room temperature curing type epoxy resin.

First, conditions for selecting an epoxy resin material will be described.
As the epoxy resin, a general-purpose bisphenol A type having an epoxy equivalent of about 190 g / eq is used. This bisphenol A type epoxy resin is a resin main material that is liquid at room temperature.

  Curing agents for curing bisphenol A type epoxy resins at room temperature include aliphatic amines and alicyclic amines, and many curing agents are commercially available. A curing agent is selected from which the time until gelation is at least 30 minutes or longer, the curing heat generation is small, and the reaction proceeds gently.

  In the case of a room temperature curing system, it is inevitable that curing heat will be generated to some extent. When curing in the drum, the temperature rises inside the solidified body due to reaction heat. The curing agent is preferably selected based on the criterion that the temperature inside the solidified body stays at least below the flash point of the organic waste liquid. For example, an alicyclic amine is a liquid at room temperature, and the curing reaction proceeds gently at room temperature.

  Next, conditions for setting the blending ratio will be described.

  An epoxy resin is added so that it may become 30 volume% or more with respect to an organic waste liquid, for example, 50 volume%. If the amount of the epoxy resin is less than this, a sufficiently uniform solidified body cannot be obtained. Conversely, when the amount of the epoxy resin is increased, the volume of the solidified body is increased as compared with the organic waste liquid, so that the amount of waste generated is increased.

  According to the results of the test and evaluation by the inventors, the amount of the epoxy resin added so that a uniform solidified body is obtained and the amount of waste generated does not increase significantly is 30% by volume or more, for example, 50% by volume.

  The addition amount of the curing agent with respect to the epoxy resin follows the recommended value of the curing agent supplier or, if there is no recommended value, is equal to the epoxy group. The amount of the curing agent is calculated using the molecular weight of the curing agent and the number of active hydrogens in the molecule.

  It is also conceivable that the components in the organic waste liquid react with the active hydrogen of the epoxy group or amine. In that case, since the efficiency of the crosslinking reaction of the epoxy resin decreases, the amount of the curing agent added to the epoxy main material may be determined in consideration of the influence of the components in the organic waste liquid.

  FIG. 2 is a block diagram showing an example of the configuration of an organic waste liquid solidification treatment apparatus containing a radioactive substance according to the present invention.

  In the first embodiment, a drum 5, an organic waste liquid supply tank 1 that supplies a predetermined amount of organic waste liquid to the drum 5, an epoxy supply tank 2 that supplies a predetermined amount of an epoxy main agent to the drum 5, and a predetermined amount to the drum 5 A curing agent supply tank 3 for supplying the curing agent, an input amount measuring means 4 for measuring a supply amount from each of the supply tanks 1, 2, 3, an organic waste liquid, an epoxy main agent, and a curing agent in the drum 5. It comprises a stirring device 5 for stirring, and a temperature measuring instrument for continuously or intermittently measuring the temperature of the organic waste liquid during stirring although not shown here.

  A certain amount of organic waste liquid is put into the drum can 5 from the organic waste liquid supply tank 1. The epoxy main agent is added from the epoxy supply tank 2 so as to be 50% by volume with respect to this fixed amount of organic waste liquid, and the organic waste liquid is stirred by the dissolver type stirring device 6.

  A predetermined amount of curing agent is added from the curing agent supply tank 3 to the organic waste liquid being stirred, and stirring is continued.

  The epoxy main agent and the curing agent immediately and uniformly dissolve each other. However, since the epoxy main agent and the curing agent are not uniform with the organic waste liquid, if the stirring is stopped in the initial stage, it is separated into two phases.

  If stirring is continued, the crosslinking of the epoxy resin proceeds and the viscosity starts to increase. If stirring is further continued, the epoxy resin having increased viscosity and the organic waste liquid are not separated, and the whole becomes uniform.

  At this time, stirring is stopped, and the stirring device 6 is pulled up from the drum 5 and washed with an epoxy main agent or the like. The epoxy main agent is used in the next organic waste liquid solidification.

  After visually confirming that the epoxy resin in the drum can 5 is cured and confirming that the organic waste liquid not taken into the cured product is not phase-separated, the drum can 5 is covered.

  In the method for solidifying an organic solution of Example 1, the organic waste liquid can be solidified while completely eliminating the possibility of ignition.

  The solidified body is stable in shape even when the temperature rises during storage, and is suitable for long-term storage.

  When the boiling point of the organic waste liquid containing the radioactive substance is high or the flash point is high, a thermosetting epoxy resin can be used for solidifying the organic waste liquid.

  In this case, it is possible to obtain a solidified body having a higher crosslinking density and more stable than using a room temperature curing type epoxy resin.

  The basic treatment process is the same when a material for curing the epoxy resin by heating is selected as the curing agent.

  The procedure different from the case of the room temperature curable epoxy resin is to stir the drum can while being heated from the outside with a heater. A winding heater that heats the drum 5 from the side is used.

  It is important to select the type of curing agent and set the curing temperature so that the temperature of the epoxy resin does not exceed the flash point of the organic waste liquid.

  When the organic waste liquid does not phase separate from the epoxy resin, stirring is stopped and heating is continued. After confirming the curing of the epoxy resin, turn off the heater, let it cool to room temperature, and cover the drum can.

  Note that the epoxy resin used in the solidification method of Example 2 may be a flame-retardant epoxy resin such as a brominated epoxy resin.

  A flame retardant such as aluminum hydroxide may be added to make a solidified body.

  In the solidification method of Example 2, an organic waste liquid having a relatively high flash point can be made into a stable solidified body.

  The solidified body is stable in shape even when the temperature rises during storage, and is suitable for long-term storage.

  Moreover, since a thermosetting epoxy resin is used, a solidified body having a high crosslinking density and a high strength can be obtained.

It is a flowchart which shows the process sequence of the solidification processing method of the organic waste liquid containing the radioactive substance by this invention. It is a block diagram which shows an example of a structure of the solidification processing apparatus of the organic waste liquid containing the radioactive substance by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Organic waste liquid supply tank 2 Epoxy main agent supply tank 3 Hardener supply tank 4 Input amount measuring means 5 Drum can 6 Stirrer

Claims (15)

In a method for solidifying an organic solution containing at least a harmful substance such as a radioactive substance,
A method for solidifying an organic solution, characterized in that a polymer material is crosslinked and solidified in an organic waste liquid. In the solidification processing method of the organic waste liquid of Claim 1,
A method for solidifying organic waste liquid, wherein the polymer material is a thermosetting resin such as an epoxy resin, a phenol resin, or a polyester resin. In a method for solidifying an organic solution containing at least a harmful substance such as a radioactive substance,
Add epoxy base and curing agent to organic solution,
A method for solidifying an organic solution, wherein the epoxy resin is crosslinked in an organic waste liquid while stirring them. In the solidification processing method of the organic waste liquid according to claim 3,
A method for solidifying an organic waste liquid, characterized in that a crosslinking reaction of an epoxy resin proceeds at room temperature or higher. In the solidification processing method of the organic waste liquid according to claim 3,
A method for solidifying an organic liquid waste, characterized in that the crosslinking reaction of an epoxy resin is a combination of an epoxy main agent and a curing agent that proceed at room temperature. In the solidification processing method of the organic waste liquid according to claim 3,
A solidification method for machine waste liquid, characterized in that the reaction between the epoxy main agent and the curing agent proceeds at a temperature not exceeding the temperature related to the handling safety of the organic waste liquid, such as the boiling point and flash point of the organic waste liquid. In the solidification processing method of the organic waste liquid according to claim 3,
The epoxy main agent is a liquid resin of bisphenol A type,
A method for solidifying an organic liquid waste, wherein the curing agent is an aliphatic amine or an alicyclic amine. In the solidification processing method of the organic waste liquid according to claim 7,
Addition amount of bisphenol A type epoxy base agent to organic waste liquid is 30% by volume or more,
A method for solidifying an organic liquid waste, comprising adding a curing agent of an aliphatic amine or an alicyclic amine so that the amount of active hydrogen is substantially equal to an epoxy group of a main agent. In the solidification processing method of the organic waste liquid according to claim 3,
A method for solidifying an organic waste liquid, characterized in that the stirring is stopped when the mixture of the epoxy main agent and the curing agent no longer separates in the organic waste liquid. In the solidification processing method of the organic waste liquid according to claim 3,
A method for solidifying an organic liquid waste, wherein the epoxy main agent is a flame retardant epoxy main agent containing a halogen. In the solidification processing method of the organic waste liquid according to claim 3,
A method for solidifying organic waste liquid, comprising adding a flame retardant that prevents combustion of the organic waste liquid.   A solidified product obtained by solidifying an organic solution containing at least a harmful substance such as a radioactive substance with a thermosetting resin such as an epoxy resin.   A waste management method in which an organic solution containing at least a harmful substance such as a radioactive substance is solidified with a thermosetting resin such as an epoxy resin and stored. In solidification processing equipment for organic solutions containing at least harmful substances such as radioactive substances,
A container such as a drum,
An organic waste liquid supply tank for supplying a predetermined amount of organic waste liquid to the container;
An epoxy supply tank for supplying a predetermined amount of the epoxy main agent to the container;
A curing agent supply tank for supplying a predetermined amount of the curing agent to the container;
Input amount measuring means for measuring the supply amount from each supply tank;
An agitation device for agitating the organic waste liquid, the epoxy main agent and the curing agent in the container;
An organic waste liquid solidification treatment apparatus comprising: a temperature measuring device that continuously or intermittently measures the temperature of the organic waste liquid during stirring. In solidification processing equipment for organic solutions containing at least harmful substances such as radioactive substances,
A container such as a drum,
An organic waste liquid supply tank for supplying a predetermined amount of organic waste liquid to the container;
An epoxy supply tank for supplying a predetermined amount of the epoxy main agent to the container;
A curing agent supply tank for supplying a predetermined amount of the curing agent to the container;
A heater for heating the organic waste liquid in the container to a predetermined temperature;
Input amount measuring means for measuring the supply amount from each supply tank;
An agitation device for agitating the organic waste liquid, the epoxy main agent and the curing agent in the container;
An organic waste liquid solidification treatment apparatus comprising: a temperature measuring device that continuously or intermittently measures the temperature of the organic waste liquid during stirring.

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