阅读说明：本技术 一种稳定放射性核素的废树脂处理方法 (Waste resin treatment method for stabilizing radioactive nuclide ) 是由 岳仁亮 周宏宇 宋平 郑继龙 冯丽华 于 2019-10-23 设计创作，主要内容包括：本发明公开了一种稳定放射性核素的废树脂处理方法,包括废树脂初步降解,化学螯合剂稳定化以及聚酯固化。所述的废树脂的初步降解首先用二氯甲烷对树脂进行预处理,得到疏松多孔的结构,然后用氢氧化钠(NaOH)的微波辅助降解废树脂；所述的化学螯合剂稳定化即将废树脂中的放射性核素通过添加螯合剂的形式,使其形成稳定的螯合物,化学螯合剂作为稳定剂对核素起固定作用；所述的聚酯固化包括红泥(RM)、微粉化粘土和聚酯。相对于现有技术,本发明将废树脂初步处理后将放射性核素稳固化的处理方式,固化配方简单,操作方便,安全可靠,且固化配方实用性强,抗压强度高,具有很高的抗渗性,且耐高温。(The invention discloses a method for treating waste resin for stabilizing radioactive nuclide, which comprises the steps of primary degradation of waste resin, stabilization of chemical chelating agent and polyester solidification. The initial degradation of the waste resin is to use methylene chloride to pretreat the resin to obtain a loose and porous structure, and then use the microwave assistance of sodium hydroxide (NaOH) to degrade the waste resin; the chemical chelating agent is used for stabilizing radionuclide in the waste resin to form a stable chelate by adding a chelating agent, and the chemical chelating agent is used as a stabilizing agent to fix nuclide; the polyester cure includes Red Mud (RM), micronized clay, and polyester. Compared with the prior art, the invention has the advantages that the treatment mode of stably curing the radionuclide after the waste resin is primarily treated is simple in curing formula, convenient to operate, safe and reliable, strong in practicability of the curing formula, high in compressive strength, very high in impermeability and high-temperature resistance.)

1. A method for treating waste resin of stable radionuclide comprises the following steps;

1) primarily degrading waste resin;

the initial degradation of the waste resin comprises the steps of firstly pretreating the resin by dichloromethane DCM to obtain a loose and porous structure, and then degrading the waste resin by the aid of microwaves of sodium hydroxide NaOH;

2) stabilizing a chemical chelating agent;

the chemical chelating agent is used for stabilizing radionuclide in the waste resin to form a stable chelate by adding a chelating agent, and the chemical chelating agent is used as a stabilizing agent to fix nuclide;

3) solidifying the polyester;

the polyester curing comprises red mud RM, micronized clay and polyester.

2. The method for treating waste resin for stabilizing radionuclide according to claim 1, characterized in that: the ratio of dichloromethane to waste resin in the preliminary degradation of the waste resin in the first step is 2: 4-2: 6(w/w), and the preliminary degradation is carried out on the resin by using dichloromethane for 24-48 h.

3. The method for treating waste resin for stabilizing radionuclide according to claim 1, characterized in that: when the waste resin in the first step is initially degraded, the waste resin is oscillated in a water bath constant temperature oscillator at a certain rotating speed in a NaOH solution at normal temperature, the rotating speed in the water bath is 150-200 r/min, the oscillating time in the water bath constant temperature oscillator is 50-60 min, the NaOH concentration of the NaOH in the waste resin in the initial degradation of the waste resin is 5-10 mol/L, and the solid-to-liquid ratio of the waste resin to the NaOH in the initial degradation of the waste resin is 1: 5.

4. The method for treating waste resin for stabilizing radionuclide according to claim 3, characterized in that: and (3) primarily degrading the waste resin, placing the waste resin in a microwave oven, heating the waste resin for a period of time under certain microwave power, raising the temperature to 130 ℃, continuing to react, and cooling the waste resin to room temperature, wherein the microwave frequency is 200-700W, and the microwave time is 50-60 min.

5. The method for treating waste resin for stabilizing radionuclide according to claim 1, characterized in that: and stabilizing the chemical chelating agent in the second step by adding an organic chelating agent, wherein the organic chelating agent is one or more of dithiocarbamic acid, dithiocarbamic acid dipotassium salt, thiourea or a mixture of citric acid and glycolic acid, the chemical chelating agent stabilizing treatment system is in a weak acid, neutral or weak base condition, and the pH of the mixed solution is 5-8.

6. The method for treating waste resin for stabilizing radionuclide according to claim 5, characterized in that: the chemical chelating agent can precipitate the chelated radionuclide in a form of adding a flocculating agent during the stabilizing action, not only can accelerate the precipitation of the chelate, but also can flocculate the excessive added chelating agent, and the flocculating agent is polyaluminum ferric chloride (PAFC) solution or Polymeric Aluminum Ferric Chloride (PAFC)Polyaluminum chloride PAC solution with concentration of 10.0 mg/mL^-1。

7. The method for treating waste resin for stabilizing radionuclide according to claim 1, characterized in that: the red mud RM in the polyester solidification in the third step is waste bauxite with superfine grain diameter, and mainly contains alkali metal, ferric oxide and hydroxide, aluminum hydroxide, calcium carbonate, titanium and silicon dioxide; the micronized clay MC is soil sediment, and kaolinite and montmorillonite are main clay minerals; the polyester is prepared from polyethylene glycol terephthalate by using cobalt naphthenate as an accelerator and methyl ethyl ketone peroxide as a catalyst, and the ratio of red mud, micronized clay and polyester in polyester curing is 1:1: 2-1: 1: 4.

8. The method for treating a waste resin for stabilizing a radionuclide according to any of claims 1 to 7, characterized in that: the waste resin is dehydrated radioactive ion exchange resin.

Technical Field

The invention relates to the technical field of waste treatment of nuclear power plants, in particular to a method for treating waste resin of stable radionuclide.

Background

Ion exchange resin is used in a primary loop cooling system, a secondary loop condensed water purification system, a spent fuel pool water purification system, a waste water purification system and the like of a reactor, and when the ion exchange resin fails, the reused radioactive nuclide-containing waste resin is called as radioactive waste resin, which is called as waste resin for short. The waste resin is organic waste which generates flammable gases such as H2, CH4, NH3, etc. upon irradiation, pyrolysis, or biodegradation; the waste resin contains polysulfide and nitrogen, and degradation products have stronger corrosivity on equipment and a storage container; the waste resin is a dispersive substance, if the waste resin is not treated, the waste resin is irradiated and decomposed to generate combustible gas in the long-term storage process, and the safety of the waste resin in the long-term storage cannot be ensured, so the waste resin must be subjected to stabilization treatment and packaging to meet the requirements of waste transportation and final disposal. The waste resin is therefore also a radioactive waste that is difficult to handle in nuclear power plants.

The waste resin treatment technology comprises nuclide separation method, solidification, oxidative decomposition, high integrity container, thermal state super compression and the like. The cement curing application is relatively wide, the technology is relatively mature, the process is simple, the cost is low, but the capacity increase ratio of a cured body is large due to the resin package capacity, if the proportion of waste resin is increased, the mechanical strength is possibly reduced, the stability of the cured body is influenced, the long-term safe disposal stability of the waste resin is poor, the leaching rate is high, cracks are easy to generate, and the like, so that the long-term safe disposal is not facilitated. From the viewpoint of achieving waste minimization, the conventional cement setting technology has been challenged by a treatment process having a significant volume reduction effect.

Disclosure of Invention

In order to solve the existing problems, the invention provides a method for treating waste resin of stable radionuclide, which can not only improve the content of waste, but also avoid the leaching of harmful substances, and the solidified material polyester injection has more advantages than the cement and other mixture injection, the solidification speed is fast, the solidified body stability is strong, the solidified body compressive strength is high, the leaching rate is extremely low, and all meet the national standard, therefore, the invention provides a method for treating waste resin of stable radionuclide, which has the following specific steps;

1) primarily degrading waste resin;

the initial degradation of the waste resin comprises the steps of firstly pretreating the resin by dichloromethane DCM to obtain a loose and porous structure, and then degrading the waste resin by the aid of microwaves of sodium hydroxide NaOH;

2) stabilizing a chemical chelating agent;

the chemical chelating agent is used for stabilizing radionuclide in the waste resin to form a stable chelate by adding a chelating agent, and the chemical chelating agent is used as a stabilizing agent to fix nuclide;

3) solidifying the polyester;

the polyester curing comprises red mud RM, micronized clay and polyester.

As a further improvement of the method, the ratio of dichloromethane to the waste resin in the preliminary degradation of the waste resin in the first step is 2: 4-2: 6(w/w), and the pretreatment time of the resin by using dichloromethane for the preliminary degradation is 24-48 h.

As a further improvement of the method, when the waste resin in the first step is primarily degraded, the waste resin is oscillated in a water bath constant temperature oscillator at a certain rotating speed in NaOH solution at normal temperature, the rotating speed in the water bath is 150-200 r/min, the oscillating time in the water bath constant temperature oscillator is 50-60 min, the NaOH concentration of the NaOH in the waste resin primarily degraded by the aid of microwaves of the NaOH is 5-10 mol/L, and the solid-to-liquid ratio of the waste resin to the NaOH in the waste resin primarily degraded is 1: 5.

As a further improvement of the invention, the waste resin is primarily degraded and placed in a microwave oven, heated for a period of time under certain microwave power, heated to 130 ℃, continuously reacted, and cooled to room temperature, wherein the microwave frequency is 200-700W, and the microwave time is 50-60 min.

According to a further improvement of the invention, the chemical chelating agent in the second step is stabilized by adding an organic chelating agent, wherein the organic chelating agent is one or more of dithiocarbamic acid, dithiocarbamic acid dipotassium salt, thiourea or a mixture of citric acid and glycolic acid, the chemical chelating agent stabilizing treatment system is in a weak acid, neutral or weak base condition, and the pH of the mixed solution is 5-8.

As a further improvement of the invention, the chemical chelating agent can be used for stabilizing, in a form of adding a flocculating agent, the flocculating agent can precipitate the chelated radionuclide, not only can accelerate the precipitation of the chelate, but also can flocculate the excessive added chelating agent, the flocculating agent is Polymeric Aluminum Ferric Chloride (PAFC) solution or Polymeric Aluminum Chloride (PAC) solution, and the concentration of the flocculating agent is 10.0m_g·mL-¹。

As a further improvement of the invention, the red mud RM in the polyester solidification of the third step is waste bauxite with ultra-fine grain diameter, mainly containing alkali metals, iron oxide and hydroxide, aluminum hydroxide, calcium carbonate, titanium and silicon dioxide; the micronized clay MC is soil sediment, and kaolinite and montmorillonite are main clay minerals; the polyester is prepared from polyethylene glycol terephthalate by using cobalt naphthenate as an accelerator and methyl ethyl ketone peroxide as a catalyst, and the ratio of red mud, micronized clay and polyester in polyester curing is 1:1: 2-1: 1: 4.

As a further improvement of the invention, the waste resin is dehydrated radioactive ion exchange resin.

In general, compared with the prior art, the above technical solutions contemplated by the present invention provide a method for treating waste resin to stabilize radionuclides, which includes the steps of preliminary degradation of waste resin, stabilization of chemical chelating agent, and solidification of polyester. The initial degradation of the waste resin is to use methylene chloride to pretreat the resin to obtain a loose and porous structure, and then use the microwave assistance of sodium hydroxide (NaOH) to degrade the waste resin; the chemical chelating agent is used for stabilizing radionuclide in the waste resin to form a stable chelate by adding a chelating agent, and the chemical chelating agent is used as a stabilizing agent to fix nuclide;

the polyester cure includes Red Mud (RM), micronized clay, and polyester. Compared with the prior art, the invention has the advantages that the treatment mode of stably curing the radionuclide after the waste resin is primarily treated is simple in curing formula, convenient to operate, safe and reliable, strong in practicability of the curing formula, high in compressive strength, very high in impermeability and high-temperature resistance.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments below:

the invention provides a method for treating waste resin of stable radionuclide, which can not only improve the content of waste, but also avoid the leaching of harmful substances, and the solidified material polyester injection has more advantages than the injection of cement and other mixtures, and has the advantages of high solidification speed, strong solidified body stability, high solidified body compressive strength and extremely low leaching rate, and all the steps accord with the national standard.

The invention discloses a method for treating waste resin for stabilizing radioactive nuclide, which comprises the steps of primary degradation of waste resin, stabilization of chemical chelating agent and polyester solidification; the process comprises the following steps: removing water from the waste resin, treating with dichloromethane, adding into sodium hydroxide solution, reacting for a while, adjusting pH, adding chelating agent, stabilizing, and curing.

The initial degradation of the waste resin comprises the steps of firstly pretreating the resin by using Dichloromethane (DCM) to obtain a loose and porous structure, and then degrading the waste resin by using the microwave assistance of sodium hydroxide (NaOH); the chemical chelating agent is used for stabilizing radionuclide in the waste resin to form a stable chelate by adding a chelating agent, and the chemical chelating agent is used as a stabilizing agent to fix nuclide; the polyester cure includes Red Mud (RM), micronized clay, and polyester.

Further, the ratio of the dichloromethane to the waste resin in the preliminary degradation of the waste resin is 2: 4-2: 6(w/w), such as 2:4, 2:5 and 2: 6.

And the resin is pretreated by dichloromethane for 24-48 h in the primary degradation.

Further, the concentration of sodium hydroxide (NaOH) in the waste resin preliminary degradation microwave-assisted degradation waste resin is 5-10 mol/L, such as 5mol/L, 6mol/L, 7mol/L, 8mol/L, 9mol/L and 10 mol/L.

The solid-to-liquid ratio of the waste resin to sodium hydroxide (NaOH) in the preliminary degradation of the waste resin is 1: 5;

when the waste resin is primarily degraded, firstly, the waste resin is oscillated in a NaOH solution at normal temperature and a certain rotating speed in a water bath constant temperature oscillator;

preferably, the rotational speed in the water bath is 150 to 200r/min, such as 150r/min, 180r/min and 200 r/min.

Preferably, the oscillation time in a water bath constant temperature oscillator is 50-60 min; for example 50min, 55min and 60 min.

The waste resin is primarily degraded and placed in a microwave oven, heated for a period of time under certain microwave power, heated to 130 ℃, continuously reacted and cooled to room temperature;

preferably, the microwave frequency is 200-700W, such as 200W, 300W, 400W, 500W, 600W, 700W.

Preferably, the microwave time is 50-60 min.

Furthermore, the chemical chelating agent has better stability by adding an organic chelating agent during the stabilization;

wherein the organic chelating agent is one or more of dithiocarbamic acid, dipotassium dithiocarbamic acid, thiourea or a mixture of citric acid and glycolic acid.

Further, the chemical chelating agent stabilizing treatment system is in a weak acid, neutral or weak base condition;

preferably, the pH of the mixture is 5 to 8, for example, pH 5, 6, 7 and 8.

Furthermore, the chemical chelating agent can be added in a form of a flocculating agent during the stabilizing action, and the flocculating agent can precipitate the chelated radionuclide, so that the precipitation of the chelate can be accelerated, and the excessive added chelating agent can be flocculated;

preferably, the flocculant can be a polyaluminum ferric chloride (PAFC) solution or a polyaluminum chloride (PAC) solution, and the concentration is 10.0 mg-mL < -1 >.

Further, said polyester curing medium Red Mud (RM) is ultra-fine particle size waste bauxite containing mainly alkali metals, iron oxides and hydroxides, aluminum hydroxide, calcium carbonate, titanium and silica; the Micronized Clay (MC) is a soil deposit, kaolinite and montmorillonite are the main clay minerals; the polyester is prepared by using polyethylene glycol terephthalate as an accelerating agent in the presence of cobalt naphthenate and using methyl ethyl ketone peroxide as a catalyst;

preferably, the ratio of the red mud, the micronized clay and the polyester in the polyester curing is 1:1:2 to 1:1:4, such as 1:1:2, 1:1:3 and 1:1: 4.

The waste resin is dehydrated radioactive ion exchange resin.

The position of the ultraviolet lamp light source can be arbitrary and is not limited, for example, it can be arranged above the housing 19 of the device.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, but any modifications or equivalent variations made according to the technical spirit of the present invention are within the scope of the present invention as claimed.