WO2019192043A1 - Method and device for treating radioactive waste liquid - Google Patents

Abstract

Disclosed is a method for treating radioactive waste liquid, the method comprising: subjecting the radioactive waste liquid to a separation treatment to obtain a first purification liquid and a concentrated liquid; subjecting the concentrated liquid to an ion exchange treatment to obtain a second purification liquid, wherein the first purification liquid and the second purification liquid are discharged; alternatively, the second purification liquid is returned to the separation treatment step, and the first purification liquid is discharged; alternatively, part of the second purification liquid is returned to the separation treatment step, and the first purification liquid and the remaining portion of the second purification liquid are discharged. Disclosed is a device for treating radioactive waste liquid by using the above-mentioned method. The method and device for treating radioactive waste liquid have a higher radioactive waste liquid purification level, and can significantly reduce the amount of radioactive waste generated, thereby achieving the miinimization of radioactive waste.

Description

Radioactive waste liquid processing method and device

Cross-reference to related applications

The present application claims the benefit of priority to the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the disclosure.

Technical field

The present application relates to the technical field of radioactive waste liquid treatment, and in particular, to a method and a device for treating radioactive waste liquid.

Background technique

For the radioactive waste liquid generated in the nuclear industry, the reverse osmosis treatment has the characteristics of good effluent quality, low energy consumption and strong adaptability. The ion exchange has a good removal effect on the radionuclide in the form of ions in the waste liquid. , are common processing techniques.

Due to the complex and low content of radioactive components in radioactive waste liquids, in order to meet the increasing requirements for environmental radiation protection in the construction of nuclear industry, a combined treatment process for radioactive waste liquids is currently used. The conventional reverse osmosis treatment and ion exchange combination process is: a reverse osmosis membrane device and an ion exchanger are combined in series, and the reverse osmosis membrane device separates the radioactive waste liquid into a purification liquid and a concentrated liquid, and the activity of the purification liquid is lower than that of the radioactive liquid. The waste liquid and the concentrate have higher radioactivity than the radioactive waste liquid, and the purified liquid enters the ion exchanger for further purification treatment. Among them, the concentrated liquid produced by the separation of the radioactive waste liquid needs to be solidified by the solidification process for treatment, and the volumetric capacity of the radioactive waste liquid in the solidified body is only about 20%, resulting in a large amount of secondary radioactive solid waste, and the treatment process is complicated; Since the concentration of the radionuclide in the purification liquid is lowered to a lower level, the utilization rate of the ion exchange resin is also lower, resulting in a larger amount of secondary radioactive solid waste.

Therefore, there is a need for a new method and apparatus for treating radioactive waste to miniaturize radioactive waste.

Summary of the invention

According to an embodiment of the present application, a radioactive waste liquid processing method and apparatus are provided, which have a higher level of radioactive waste liquid purification, and can significantly reduce the amount of radioactive waste generated, thereby achieving a small quantification of radioactive waste.

According to an aspect of an embodiment of the present application, a method for treating a radioactive waste liquid is provided, the method comprising: separating a radioactive waste liquid to obtain a first purification liquid and a concentrated liquid; and performing ion exchange treatment on the concentrated liquid to obtain a first a second purification liquid; wherein, the first purification liquid and the second purification liquid are discharged; or the second purification liquid is returned to the separation treatment process to discharge the first purification liquid; or, the second purification liquid is returned to the separation treatment In the process, the first purification liquid is discharged to the remaining second purification liquid.

According to the radioactive waste liquid treatment method of the embodiment of the present application, the first purification liquid that meets or even exceeds the discharge standard is obtained by separating the radioactive waste liquid, and the radionuclide is substantially retained in the concentrated liquid, and the concentrated liquid has a higher concentration. The concentration of the radionuclide, which is ion-exchanged, can significantly improve the utilization efficiency of the ion exchange resin, thereby significantly reducing the amount of radioactive waste ion exchange resin. Since the method does not produce a radioactive concentrate, the curing process is eliminated, thereby further reducing the amount of radioactive waste generated.

According to another aspect of embodiments of the present application, there is also provided a radioactive waste liquid processing apparatus, comprising: a separation unit, an ion exchange unit, and a drainage unit, wherein a concentrate outlet of the separation unit is connected to an inlet of the ion exchange unit; The purification liquid outlet of the separation unit is connected to the drainage unit; the purification liquid outlet of the ion exchange unit is connected to the inlet of the drainage unit and/or the separation unit.

DRAWINGS

In order to explain the technical solutions of the embodiments of the present application, the drawings used in the embodiments of the present application will be briefly introduced. For those skilled in the art, without any creative work, Other drawings can be obtained from these figures.

FIG. 1 is a schematic view showing a process flow of a method for treating a radioactive waste liquid provided by an embodiment of the present application.

Fig. 2 is a graph showing the relationship between the equilibrium adsorption amount Q of the ion exchange resin to the radionuclide oxime and the equilibrium concentration Ce of the radionuclide ruthenium in the solution.

FIG. 3 is a schematic diagram showing the process flow of a radioactive waste liquid processing apparatus provided by an embodiment of the present application.

FIG. 4 is a schematic view showing the process flow of a radioactive waste liquid processing apparatus according to another embodiment of the present application.

FIG. 5 is a schematic diagram showing the process flow of a radioactive waste liquid processing apparatus according to another embodiment of the present application.

FIG. 6 is a flow chart showing the process of a radioactive waste liquid processing apparatus provided by another embodiment of the present application.

FIG. 7 is a flow chart showing the process of a radioactive waste liquid processing apparatus provided by another embodiment of the present application.

Label description:

10, water supply pump;

100, a preprocessing unit;

101, activated carbon filter; 102, inorganic adsorption column; 103, oil water separator; 104, security filter; 105, buffer water tank; 106, paper core filter; 107, self-cleaning filter; 108, ultrafilter;

200, a separation unit;

201, buffer water tank; 202, security filter; 203, high pressure pump; 204, circulating pump;

210, a reverse osmosis subunit;

211, a first-stage reverse osmosis device; 212, a second-stage reverse osmosis device; 213, a reverse osmosis device;

221, first-stage continuous electric desalination equipment; 222, second-stage continuous electric desalination equipment; 223, intermediate water tank; 224, activator tank;

300, an ion exchange unit;

301, an ion exchanger;

400, drainage unit;

401, water tank.

detailed description

The present application will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are only to be construed as illustrative and not limiting. The application may be practiced without some of these specific details, as will be apparent to those skilled in the art. The following description of the embodiments is merely provided to provide a better understanding of the invention

It should be noted that, in this context, relational terms such as first and second are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply such entities or operations. There is any such actual relationship or order between them. Furthermore, the term "comprises" or "comprises" or "comprises" or any other variations thereof is intended to encompass a non-exclusive inclusion, such that a process, method, article, or device that comprises a plurality of elements includes not only those elements but also Other elements, or elements that are inherent to such a process, method, item, or device. An element that is defined by the phrase "comprising", without limiting the invention, does not exclude the presence of additional elements in the process, method, article, or device.

Radioactive wastewater treatment is different from conventional wastewater treatment because: 1) the mass concentration of radionuclide ions in radioactive wastewater is extremely low, and the mass concentration of radionuclide ions is further reduced to achieve the environmental emission requirement of 10Bq. /L, which far exceeds the capacity of conventional wastewater treatment technology; 2) An important principle of radioactive wastewater treatment is the small quantification of radioactive waste; 3) the operability and maintainability of equipment under radioactive conditions need to be considered.

Based on the above special requirements of radioactive waste water treatment, the embodiments of the present application provide a radioactive waste liquid treatment method and device, which have higher radioactive waste liquid purification level, and can significantly reduce the amount of radioactive waste generated, and realize small radioactive waste. Quantify.

In this paper, the "concentration factor" is calculated as (influent volume) / (volume of concentrate); "reverse osmosis recovery" is calculated as (reverse osmosis total purified liquid production) / (reverse osmosis total water intake).

FIG. 1 is a schematic view showing a process flow of a method for treating a radioactive waste liquid provided by an embodiment of the present application, according to which:

The radioactive waste water is first separated and treated to obtain a first purified liquid and a concentrated liquid. Wherein, the concentration factor is more than 2 times, preferably 2 to 3 times, and the majority of the radioactive nuclides in the radioactive waste water are retained in the concentrate, so that the mass concentration of the radionuclide in the concentrate can reach the radioactivity in the radioactive waste liquid. The mass concentration of radionuclides in the first purification liquid is less than twice the mass concentration of radionuclides, which is lower than the mass concentration of radionuclides in the radioactive waste water, which is even better than the emission standard (radioactivity is less than 10Bq/ L), discharge treatment.

Further, the concentrate is subjected to ion exchange treatment to obtain a second purification liquid. In this way, since the radioactive concentrated waste liquid is not generated, the curing process is eliminated, and the amount of radioactive waste generated is reduced. On the other hand, as shown in Fig. 2, the relationship between the equilibrium adsorption amount Q of the ion exchange resin to the radionuclide iridium and the equilibrium concentration Ce of the radionuclide iridium in the solution is shown, and it can be seen that the radionuclide is in solution. The higher the equilibrium concentration Ce in the ion, the higher the equilibrium adsorption amount Q of the ion exchange resin to the radionuclide. In the above separation treatment step, the mass concentration of the radionuclide in the concentrated liquid can be more than twice the mass concentration of the radionuclide in the radioactive waste liquid, and the concentrated liquid has a high concentration of radionuclides, and ion exchange is performed. The treatment can significantly improve the utilization efficiency of the ion exchange resin, thereby significantly reducing the amount of generation of the radioactive waste ion exchange resin, and achieving a small amount of radioactive waste.

After detecting that the activity of the second purification liquid meets the requirements of the emission standard, the discharge treatment is performed. At this time, the first purification liquid and the second purification liquid may be directly discharged, or the two may be mixed and discharged. After detecting that the second purification liquid is mixed with the first purification liquid and meets the requirements of the discharge standard, the second purification liquid is mixed with the first purification liquid and then discharged.

It is also possible to return all or part of the second purification liquid as a part of the influent water in the separation treatment step, which can reduce the concentration of the radionuclide in the water entering the separation treatment step, thereby improving the decontamination effect of the whole process method on the radionuclide.

According to some embodiments of the present application, the separation treatment may adopt one or more of a nanofiltration process, a reverse osmosis process, and a continuous electric desalination process according to actual conditions such as the composition, content, and processing requirements of the radioactive waste water. Combination process.

Although the separation performance of the nanofiltration process is lower than that of the reverse osmosis process, the nanofiltration process has certain selectivity for ion separation, and has the advantages of low process osmotic pressure, low operating pressure, and energy saving, so that it is desirable to select a purification liquid. Some ions are retained in nature, and the nanofiltration process can be used as a preferred process for the separation of radioactive wastewater.

When the separation treatment process adopts the reverse osmosis process, the first-stage or two-stage reverse osmosis process may be used, but it is not limited thereto, and the three-stage, four-stage or more reverse osmosis process may be adopted according to actual conditions.

As an example, the radioactive waste liquid is subjected to a first-stage reverse osmosis process to obtain a first-stage reverse osmosis purification liquid and a first-stage reverse osmosis concentrate as the first purification liquid and the concentrated liquid, respectively.

Alternatively, the first-stage reverse osmosis process may employ one or two or more stages of reverse osmosis treatment. When two or more stages of reverse osmosis treatment are used, the upper stage reverse osmosis treated intermediate concentrate is used as the next stage of reverse osmosis treatment. That is, the radioactive waste liquid is subjected to reverse osmosis treatment of two or more stages in sequence to obtain a concentrated liquid, and at the same time, the purified liquid is sent out from each section, and the purified liquid sent from all the sections is combined into a first-stage reverse osmosis concentrate.

As another example, the radioactive waste liquid is first sent to the first-stage reverse osmosis process to obtain the first-stage reverse osmosis purification liquid and the first-stage reverse osmosis concentrate, and then the first-stage reverse osmosis purification liquid is sent to the second stage. The reverse osmosis process is processed to obtain a second-stage reverse osmosis purification liquid and a second-stage reverse osmosis concentrate. Wherein, the second-stage reverse osmosis concentrate is returned to the first-stage reverse osmosis process, and the first-stage reverse osmosis concentrate is used as the concentrate to be sent to the ion exchange treatment process; the second-stage reverse osmosis purification liquid is less than 10 Bq/ L, in line with the requirements of the discharge standard, as the first purification liquid for discharge treatment.

Optionally, the first-stage reverse osmosis process may adopt one or two or more stages of reverse osmosis treatment. When two or more stages of reverse osmosis treatment are used, the intermediate concentrate produced by the reverse osmosis treatment of the previous stage is used as the next stage of reverse osmosis treatment. The influent water, that is, the radioactive waste liquid is subjected to reverse osmosis treatment of two or more stages in sequence to obtain a concentrated liquid, and the purified liquid is sent out from each section, and the purified liquid sent from all the sections is merged into the first-stage reverse osmosis purification liquid.

Alternatively, the second-stage reverse osmosis process may employ one or two or more stages of reverse osmosis treatment. Similarly, when two or more stages of reverse osmosis treatment are used, the intermediate concentrate produced by the reverse osmosis treatment as the next stage is reversed. The infiltrated influent, that is, the radioactive waste liquid is subjected to reverse osmosis treatment of two or more stages in sequence to obtain a second-stage reverse osmosis concentrate, and the purified liquid is sent from each section, and the purified liquid sent from all the sections is merged into the second stage. Reverse osmosis purification solution.

As an alternative, the first-stage reverse osmosis process and the second-stage reverse osmosis process all adopt three-stage reverse osmosis treatment to form a “two-stage three-stage” reverse osmosis process for separation of radioactive wastewater pairs, which has high purification. Capacity and concentration factor reduce the load on the ion exchange treatment process while increasing the reverse osmosis recovery rate.

When the first-stage reverse osmosis purification liquid produced by the first-stage reverse osmosis process or the second-stage reverse osmosis purification liquid produced by the two-stage reverse osmosis process has a radioactivity of more than 10 Bq/L, or when pursuing the discharged purification liquid When the lower activity can be achieved, the first-stage reverse osmosis purification liquid produced by the first-stage reverse osmosis process or the second-stage reverse osmosis purification liquid produced by the two-stage reverse osmosis process can be sent to the continuous electric desalination process. Further fine processing is performed. The fine treatment may be a one-stage or two-stage continuous electric desalination process, but is not limited thereto, and a three-stage, four-stage or higher continuous electric desalination process may be adopted according to actual conditions.

As an example, the first-stage reverse osmosis purification liquid produced by the first-stage reverse osmosis process or the second-stage reverse osmosis purification liquid produced by the two-stage reverse osmosis process is subjected to a first-stage continuous electric desalination process for fine treatment to obtain the first Purification liquids often meet the requirements of emission standards, even reach the natural background level, and discharge treatment, resulting in the return of the first-stage continuous electric desalting concentrate to the first-stage reverse osmosis process or the first-stage reverse osmosis process. Infiltration process.

In order to improve the purification level of the continuous electric desalination process, the activator may be added to the second-stage reverse osmosis purification liquid produced by the first-stage reverse osmosis process or the second-stage reverse osmosis purification liquid produced by the two-stage reverse osmosis process, and then sent. Into the first-stage continuous electric desalination process for deep purification treatment. The activator can be prepared from pure water having a resistivity of more than 0.5 MΩ·cm and different kinds of inorganic salts, and the activator contains ions Ca ²⁺ , Na ⁺ , Sr ²⁺ , Zn ²⁺ , Mg ²⁺ , Fe ^{2 . +} and K ⁺ , the type of anion is not limited, the concentration of the activator stock solution is related to the dosage, ensuring that the ion concentration in the radioactive waste water is as follows after the activator is added to the radioactive waste water and mixed uniformly: Ca ²⁺ 0.1 mg / L ~ 0.2 mg/L, Na ⁺ 0.2 mg/L to 0.3 mg/L, Sr ²⁺ 8 mg/L to 9 mg/L, Zn ²⁺ 18 mg/L to 20 mg/L, Mg ²⁺ 0.2 mg/L to 0.25 mg/ L, Fe ²⁺ 0.04 mg/L to 0.05 mg/L and K ⁺ 100 mg/L to 150 mg/L.

As another example, the first-stage reverse osmosis purification liquid produced by the first-stage reverse osmosis process or the second-stage reverse osmosis purification liquid produced by the two-stage reverse osmosis process is firstly sent to the first-stage continuous electric desalination process to obtain The first-stage continuous electric desalination purification liquid and the first-stage continuous electric demineralization concentrate, and then the first-stage continuous electric desalination purification liquid is sent to the second-stage continuous electric desalination process to obtain the second-stage continuous electric elimination The salt purification liquid and the second-stage continuous electric demineralization concentrate, wherein the second-stage continuous electric demineralization purification liquid is the first purification liquid, and has often reached the discharge standard requirement, even reaches the natural background level, and performs the discharge treatment. The first-stage continuous electric desalting concentrate and the second-stage continuous electric desalting concentrate return to the first-stage reverse osmosis process in the first-stage reverse osmosis process or the two-stage reverse osmosis process.

Similarly, in order to improve the purification level of the continuous electric desalination process, an activator may be added to the first-stage continuous electric desalination purification liquid, and then sent to a second-stage continuous electric desalination process for purification treatment. The activator may be selected from an activator as described above.

It can be understood that the separation treatment process is not limited to adopting the above process, for example, it may be a continuous electric desalination process of more than one level; a nanofiltration-reverse osmosis combination process; a nanofiltration-continuous electric desalination combination process; The reverse osmosis-continuous electric desalination combination process and the like can be determined by those skilled in the art according to actual conditions.

The radioactive waste water is optionally pretreated before the radioactive waste water is separated, but this is not an essential process.

Considering that the ruthenium and osmium (especially ruthenium) in the radioactive waste water are the easiest to penetrate the ion exchange bed, the selective adsorption characteristics of the inorganic adsorption are used to specifically adsorb the radionuclide which is easy to penetrate the ion exchange bed, thereby prolonging the use of the ion exchange resin. The cycle further reduces the amount of radioactive waste ion exchange resin produced. Based on the above considerations, when any one of the radioactive activity of cesium in the radioactive waste liquid, the radioactivity of strontium, and the total activity of strontium and strontium is 10 ⁵ Bq/L or more, it is preferable to remove strontium and/or strontium. Pretreatment. When the activity of the specific radionuclide targeted by the inorganic adsorbent exceeds a preset threshold, such as the radioactivity of rhodium in the radioactive waste liquid, the radioactivity of rhodium or the total radioactivity of rhodium and ruthenium is higher than 10 ⁴ Bq/L, at this time, the inorganic adsorbent needs to be replaced.

In addition to radionuclides and inorganic salts, radioactive waste water may also contain impurities such as oils, organic matter, colloids and particulate matter. Most of these impurities are non-radioactive, but will be produced by processes such as inorganic adsorption, reverse osmosis and ion exchange. Influence, pretreatment to remove these impurities, can extend the life cycle of inorganic adsorbents, reverse osmosis membranes, ion exchange resins, reduce the replacement of inorganic adsorbents and ion exchange resins, and further reduce the amount of radioactive waste ion exchange resin and radioactive waste inorganic The amount of adsorbent produced. Due to its unique surface properties, activated carbon has good adsorption capacity for oils, organic matter, colloids, particulate matter and other impurities. Therefore, activated carbon can be used to remove these impurities, simplifying the pretreatment process equipment and processes. When the resistance of the activated carbon bed is too large or the filtrate does not meet the subsequent water inflow requirements (contamination index SDI < 2), the activated carbon needs to be replaced.

It is also possible to adjust the pH value of the radioactive waste water to 6-8 in advance, which can make the reverse osmosis process better, and the reverse osmosis membrane has a longer service life.

In order to achieve the above method for treating a radioactive waste liquid, the embodiment of the present application further provides a radioactive waste liquid processing apparatus, which will be described in detail below with reference to FIGS. 3 to 7.

FIG. 3 is a schematic diagram showing the process flow of a radioactive waste liquid processing apparatus provided by an embodiment of the present application. The apparatus includes a separation unit 200, an ion exchange unit 300, and a drainage unit 400, wherein the radioactive waste water supply is connected to the inlet of the separation unit 200, the concentrate outlet of the separation unit 200 is connected to the inlet of the ion exchange unit 300; and the separation unit 200 is purified. The liquid outlet is connected to the drain unit 400; the purge liquid outlet of the ion exchange unit 300 is connected to the drain unit 400 and/or the inlet of the separation unit 200.

As an example, the drain unit 400 includes a first drain subunit and a second drain subunit (not shown), the purge liquid outlet of the separation unit 200 is connected to the first drain subunit, and the purge outlet of the ion exchange unit 300 Connected to the second drainage subunit, the first drainage subunit and the second drainage subunit may be in communication. In this way, when the activity of the second purification liquid is determined to meet the requirements of the emission standard, the first purification liquid and the second purification liquid may be directly discharged according to different requirements, or may be discharged after mixing the two; When the second purification liquid is mixed with the first purification liquid and meets the requirements of the discharge standard, the second purification liquid is mixed with the first purification liquid and discharged.

It can be understood that the drainage unit 400 may be only a drainage pipe, or may be connected to the production water tank 401 (shown in FIG. 6 and FIG. 7) on the drainage pipe, or other forms for discharging the purification liquid, which is not limited in the application.

The purification liquid outlet of the ion exchange unit 300 may also be connected to the inlet of the separation unit 200, and the second purification liquid may be returned in whole or in part as a part of the water entering the separation unit 200, which can reduce the concentration of the radionuclide in the water entering the separation unit 200. , thereby improving the decontamination effect of the whole device on the radionuclide.

According to some embodiments of the present application, the separation unit 200 includes one or a combination of two or more of a nanofiltration unit, a reverse osmosis subunit, a continuous electric desalting subunit.

As an example, the separation unit 200 includes a reverse osmosis subunit 210 (shown in FIG. 5), and the reverse osmosis subunit 210 employs a one-stage or two-stage reverse osmosis device, but is not limited thereto, and may also adopt three according to actual conditions. Grade, quadruple or more reverse osmosis equipment.

In some embodiments, please refer to the process flow diagram of the radioactive waste liquid processing apparatus provided by one embodiment of the present application shown in FIG. 6 , the reverse osmosis subunit 210 adopts a first stage reverse osmosis apparatus, and the concentrated liquid outlet of the reverse osmosis apparatus 213 It is connected to the inlet of the ion exchange unit 300. The purification liquid sent from the reverse osmosis apparatus 213 has been lower than 10 Bq/L, which meets the requirements of the discharge standard, and can be discharged. At this time, the purification liquid outlet of the reverse osmosis apparatus 213 is connected to the drainage unit 400.

In order to increase the reverse osmosis recovery rate, the concentrate outlet of the reverse osmosis apparatus 213 is divided into two branches via a pipe, one branch is connected to the inlet of the reverse osmosis apparatus 213, and the other branch is connected to the inlet of the ion exchange unit 300. This also reduces the discharge amount of the concentrate, reduces the load of the ion exchange unit 300, further improves the utilization of the ion exchange resin, and avoids energy waste and saves energy.

Further, the reverse osmosis device 213 may employ one reverse osmosis membrane module or two or more reverse osmosis membrane modules in series. When two or more reverse osmosis membrane modules are used, the concentrate outlet of the previous reverse osmosis membrane module is next to the next The inlet of the reverse osmosis membrane module is connected, that is, the intermediate concentrate produced by the last reverse osmosis membrane module is used as the inlet water of the next reverse osmosis membrane module, and the purification liquids sent from all the reverse osmosis membrane modules are merged into the purification liquid of the reverse osmosis apparatus 213.

In some embodiments, referring to the process flow diagram of the radioactive waste liquid processing apparatus provided by one embodiment of the present application shown in FIG. 7, the reverse osmosis subunit 210 employs a two-stage reverse osmosis apparatus, wherein the first stage reverse osmosis apparatus 211 and The second reverse osmosis device 212 is connected in two stages. Specifically, the purified liquid outlet of the first-stage reverse osmosis device 211 is connected to the inlet of the second-stage reverse osmosis device 212, and the concentrated liquid outlet of the second-stage reverse osmosis device 212 is The inlet of the primary reverse osmosis apparatus 211 is connected, and the concentrate outlet of the first stage reverse osmosis apparatus 211 is connected to the inlet of the ion exchange unit 300. The purified liquid sent from the second-stage reverse osmosis device 212 is often lower than 10 Bq/L, and meets the requirements of the discharge standard, and can be discharged. At this time, the purified liquid outlet of the first-stage reverse osmosis device 212 is connected to the drain unit 400. .

In order to increase the reverse osmosis recovery rate, the concentrate outlet of the first stage reverse osmosis apparatus 211 is divided into two branches via a pipeline, one branch is connected to the inlet of the first stage reverse osmosis apparatus 211, and the other branch is connected to the ion exchange unit. The import of 300 is connected. This also reduces the discharge amount of the concentrate, reduces the load of the ion exchange unit 300, further improves the utilization of the ion exchange resin, and avoids energy waste and saves energy.

Further, the first-stage reverse osmosis device 211 may adopt a reverse osmosis membrane module or two or more reverse osmosis membrane modules connected in series, and when more than two reverse osmosis membrane modules are used, the concentrate outlet of the previous reverse osmosis membrane module Connected to the inlet of the next reverse osmosis membrane module, the intermediate concentrate produced by the previous reverse osmosis membrane module is used as the inlet water of the next reverse osmosis membrane module, and the purification liquid sent from all the reverse osmosis membrane modules is merged into the first stage reverse osmosis. The cleaning liquid of the device 211.

The second stage reverse osmosis apparatus 212 may also employ a reverse osmosis membrane module or two or more reverse osmosis membrane modules in series, and similarly, when more than two reverse osmosis membrane modules are employed, the concentrate of the previous reverse osmosis membrane module The outlet is connected to the inlet of the next reverse osmosis membrane module, that is, the intermediate concentrate produced by the previous reverse osmosis membrane module is used as the inlet water of the next reverse osmosis membrane module, and the purification liquids sent from all the reverse osmosis membrane modules are merged into the second stage. The cleaning fluid of the infiltration device 212.

As an alternative, the first-stage reverse osmosis device 211 and the second-stage reverse osmosis device 212 are all connected in series by a three-stage reverse osmosis membrane module to form a "two-stage three-stage" reverse osmosis unit for separation and treatment of radioactive waste water. The high purification capacity and concentration factor reduce the load of the ion exchange unit 300 while increasing the reverse osmosis recovery rate.

When the first-stage reverse osmosis purification liquid produced by the first-stage reverse osmosis equipment or the second-stage reverse osmosis purification liquid produced by the two-stage reverse osmosis equipment has a radioactivity of more than 10 Bq/L, or when pursuing the discharged purification liquid When the lower activity can be achieved, a continuous electric desalting unit can be arranged downstream of the reverse osmosis subunit, and the first stage reverse osmosis purification liquid produced by the first stage reverse osmosis apparatus or the two-stage reverse osmosis process can be produced. The second stage reverse osmosis purification liquid is sent to the continuous electric desalting subunit for further fine processing. The fine treatment may be a one-stage or two-stage continuous electric desalination apparatus, but it is not limited thereto, and three-stage, four-stage or more-stage continuous electric desalination equipment may be used according to actual conditions.

As an example, when the continuous electric desalination unit uses a two-stage continuous electric desalination apparatus, please refer to FIG. 7, in which the first-stage continuous electric desalination apparatus 221 is connected in series with the second-stage continuous electric desalination apparatus 222, specifically , the purification liquid outlet of the reverse osmosis subunit, that is, the purification liquid outlet of the first-stage reverse osmosis equipment or the purification liquid outlet of the second-stage reverse osmosis equipment of the two-stage reverse osmosis equipment, and the inlet of the first-stage continuous electric desalination equipment 221 Connected, the purified liquid outlet of the first-stage continuous electric desalination device 221 is connected to the inlet of the second-stage continuous electric desalination device 222, and the purified liquid outlet of the second-stage continuous electric desalination device 222 is connected to the drain unit 400, first The concentrate outlet of the stage continuous electric desalination apparatus 221 and the concentrate outlet of the second stage continuous electric desalination apparatus 222 are connected to the inlet of the reverse osmosis subunit 210, respectively. When the reverse osmosis subunit 210 employs a primary reverse osmosis apparatus, please refer to FIG. 6. The inlet of the reverse osmosis subunit 210 refers to the inlet of the reverse osmosis apparatus 213, and when the reverse osmosis subunit 210 employs a two-stage reverse osmosis apparatus, Referring to FIG. 7, the inlet of the reverse osmosis subunit 210 refers to the inlet of the first stage reverse osmosis apparatus 211.

In order to improve the purification level of the continuous electric desalination unit, when the continuous electric desalination unit adopts the first-stage continuous electric desalination device, an intermediate water tank may be connected between the reverse osmosis subunit and the continuous electric desalination unit. The intermediate tank is connected to the activator tank. In this way, in the purification liquid sent by the reverse osmosis subunit, such as the first-stage reverse osmosis purification liquid produced by the first-stage reverse osmosis apparatus or the second-stage reverse osmosis purification liquid produced by the two-stage reverse osmosis apparatus, the activator is added, and then sent Into a first-class continuous electric desalination equipment for deep purification treatment. When the continuous electric desalination unit is connected in series by two-stage continuous electric desalination equipment, referring to FIG. 7, an intermediate water tank can be connected between the first-stage continuous electric desalination device 221 and the second-stage continuous electric desalination device 222. 223, the intermediate water tank 223 is connected to the activator tank 224, and a dosing pump is provided to control the amount of the activator to be added, so that the purified liquid produced by the continuous electric desalting subunit treatment reaches the natural background level.

According to some embodiments of the present application, referring to FIG. 6 and FIG. 7, the ion exchange unit 300 includes a primary ion exchanger 301. Of course, the ion exchangers 301 of two or more stages may be connected in series.

As shown in FIG. 4, the pre-processing unit 100 may be provided upstream of the separation unit 200, but is not essential. If necessary, the pre-processing unit 100 may be one of a water separator, an activated carbon filter, an inorganic membrane filter, a security filter, a paper core filter, a self-cleaning filter, an ultrafilter, an inorganic adsorption column, or Several combinations.

Considering that the ruthenium and osmium (especially ruthenium) in the radioactive waste water are the easiest to penetrate the ion exchange bed, the selective adsorption characteristics of the inorganic adsorption are used to specifically adsorb the radionuclide which is easy to penetrate the ion exchange bed, thereby prolonging the use of the ion exchange resin. The cycle further reduces the amount of radioactive waste ion exchange resin produced. Based on the above considerations, when any one of the radioactivity in the radioactive waste liquid, the radioactivity of the thorium, and the total radioactivity of the plutonium and thorium is 10 ⁵ Bq/L or more, it is preferably passed through the inorganic adsorption column 102 (as shown in the figure). 5 to FIG. 7) Pretreatment for removing ruthenium and/or ruthenium may be carried out using an inorganic adsorption column for ruthenium, an inorganic adsorption column for ruthenium or an inorganic adsorption column for ruthenium and osmium.

In addition to radionuclides and inorganic salts, radioactive waste water may also contain impurities such as oils, organic matter, colloids, and particulate matter. Most of these impurities are non-radioactive, but will be inorganic adsorbents, reverse osmosis membranes, and ion exchange resins. When it is affected, pretreatment removes these impurities, which can extend the life cycle of inorganic adsorbents, reverse osmosis membranes, and ion exchange resins, reduce the replacement of inorganic adsorbents and ion exchange resins, and further reduce the amount and radioactivity of radioactive waste ion exchange resins. The amount of waste inorganic adsorbent produced. Due to its unique surface properties, activated carbon has good adsorption capacity for oils, organic matter, colloids, particulate matter and other impurities. Therefore, activated carbon filter 101 (shown in Figures 5 and 6) can be used to remove these impurities and simplify pretreatment. Process equipment and processes.

Some radioactive waste water contains a large amount of impurities, and the activated carbon filter 101 has a large load. The activated carbon filter 101 cannot achieve a satisfactory impurity removal effect. Referring to FIG. 6, the pretreatment unit 100 may employ an oil-water separator 103 and an inorganic adsorption column. 102. The paper core filter 106, the self-cleaning filter 107, and the ultrafilter 108 are sequentially connected. Wherein, the oil-water separator 103 is used for removing oil impurities in the radioactive waste water, and reducing the influence of the oil impurities on the subsequent process; the inorganic adsorption column 102 is for removing the radionuclide which is easy to penetrate the ion exchange bed, and prolonging the ion exchange resin. The use period reduces the amount of generation of the radioactive waste ion exchange resin; optionally, a security filter 104 is disposed between the oil water separator 103 and the inorganic adsorption column 102 to remove particulate matter, and protect the inorganic adsorption column 102 from being blocked by adsorption. The paper core filter 106 is used for removing particulate matter in the radioactive waste water, and the filter element containing the particulate matter is convenient for subsequent treatment and disposal; the self-cleaning filter 107 directly intercepts impurities in the radioactive waste water by using the filter screen, and further removes suspended matter and particulate matter. The self-cleaning filter 107 is capable of automatically discharging sewage, improving intelligence, and making the process more efficient; the ultrafilter 108 is capable of deeply removing impurities, proteins, microorganisms, and macromolecular organic substances in a colloidal form in the radioactive waste water. The pretreatment unit 100 can deeply remove impurities in the radioactive waste water, conform to the water inflow requirement of the subsequent process, greatly reduce the influence of impurities on the separation treatment process and the ion exchange process, and improve the separation unit 200 and the ion exchange unit 300. Operation cycle. A buffer water tank 105 may be connected between the inorganic adsorption column 102 and the paper core filter 106 to buffer the radioactive waste water after the inorganic adsorption treatment.

The separation unit 200 may further include a buffer water tank 201 to buffer the radioactive waste water from the pretreatment unit 100. A security filter 202 may be further coupled between the buffer tank 201 and the reverse osmosis subunit 210 for protecting the reverse osmosis apparatus of the subsequent process.

The apparatus also includes a suitable water supply pump 10, a circulation pump 204, and a high pressure pump 203, which may be various pumps commonly used in the art, such as a plunger pump, a centrifugal pump, and the like.

By adopting the radioactive waste water treatment device provided in the embodiment of the present application, the above-mentioned radioactive waste water method can be implemented to achieve a high level of radioactive waste liquid purification, and at the same time, the amount of radioactive waste generated can be significantly reduced, and the radioactive waste can be quantified.

The present application is exemplified by the following examples, but these examples are in no way intended to limit the application.

In the following examples, the concentrations of Cs ⁺ , Sr ²⁺ , and Co ²⁺ were measured by Thermocouple Thermo Scientific ICAP Q-type inductively coupled plasma-mass spectrometry (ICP-MS). The concentration of oil was determined by Shimadzu OCT-1. Characterization was performed using a total organic carbon TOC analyzer.

The "decontamination factor" is calculated as (the activity of the influent water) / (the activity of the purified liquid).

Example 1

The radioactive waste water treatment apparatus used in this embodiment employs the apparatus shown in Fig. 6. The reverse osmosis apparatus 213 is a series of three reverse osmosis membrane modules, and each reverse osmosis membrane module is provided with a reverse osmosis membrane element Dow BW30-4040. The equipment, components and materials used in the device are shown in the following table:

The radioactive waste water treated in this example is simulated radioactive waste water, which contains Cs+2000 μg/L, Co ²⁺ 875 μg/L, Sr ²⁺ 1230 μg/L, and surfactant 10 mg/L.

The designed treatment capacity of the radioactive waste water treatment device is 1 m ³ /h, and the ion exchange bed treatment rate is about 10 BV/h.

The above simulated radioactive wastewater was pretreated by activated carbon adsorption bed. The concentration of surfactant in water was reduced to 0.98 mg/L, and the concentration of radionuclide ions was unchanged. Further, the concentration of Cs ^{+ in} water was reduced to 0.08 μg/ L, substantially completely removes Cs ⁺ from the wastewater.

The operating pressure of the high pressure pump 203 is 1.5 MPa, the reverse osmosis recovery rate is 60%, the 3 m ³ /h concentrated water is returned to the reverse osmosis circulation treatment, and the 0.67 m ³ /h concentrated water enters the ion exchange bed for ion exchange treatment, and the ion exchange purification liquid is produced. The water was 0.67 m ³ /h, and the ion exchange production water was all returned as a part of the reverse osmosis water, and the production of the reverse osmosis purification liquid reached 1 m ³ /h.

The rejection rates of the reverse osmosis device 213 for Cs ⁺ , Sr ²⁺ , and Co ²⁺ were 95%, 98%, and 98%, respectively. When the device starts to operate, the ion exchange bed has higher decontamination factors for the three radionuclide ions Cs ⁺ , Sr ²⁺ and Co ²⁺ , which are about 10 ³ respectively, and Cs ⁺ and Sr ^{2+ in the} ion exchange production water. The Co ²⁺ concentrations were 0.71 μg/L, 1.30 μg/L, and 1.80 μg/L, respectively. The ion exchange water is mixed with the simulated radioactive waste water and used as reverse osmosis water. The concentrations of Cs ⁺ , Sr ²⁺ and Co ²⁺ are 299μg/L, 525μg/L and 739μg/L, respectively. The reverse osmosis purification liquid is the device. The concentrations of Cs ⁺ , Sr ²⁺ and Co ²⁺ in the produced water were 28.5 μg/L, 20.6 μg/L and 28.9 μg/L, respectively. At this time, the decontamination factors for Cs ⁺ , Sr ²⁺ and Co ²⁺ were installed. Reached 17, 42, 43 respectively.

As the operation time of the device increases, the decontamination factors of Cs ⁺ , Sr ²⁺ and Co ²⁺ are continuously reduced in the ion exchange bed. After 400 h of operation, the ion exchange bed decontaminates Cs ⁺ , Sr ²⁺ and Co ²⁺ . The factors were 1.8, 2.1 and 2.0, respectively. The concentrations of Cs ⁺ , Sr ²⁺ and Co ²⁺ in ion exchange water were 821μg/L, 1252μg/L and 1604μg/L, respectively. Cs ⁺ , Sr ²⁺ and Co in the product water. ^{The 2+} concentrations were 59.8μg/L, 40.2μg/L and 54.1μg/L, respectively. At this time, the decontamination factors of Cs ⁺ , Sr ²⁺ and Co ²⁺ were 8, 22 and 23 respectively.

If the separation treatment is not carried out, the simulated radioactive waste water is directly purified by the ion exchange bed after being pretreated by the activated carbon adsorption bed and the ruthenium adsorption bed. After 400 hours of operation, the device goes to the total of Cs ⁺ , Sr ²⁺ and Co ²⁺ . The pollution factor is only about 2, respectively. It can be seen that, after the separation treatment is used to concentrate the radioactive waste water, the ion exchange treatment of the concentrated liquid can greatly improve the decontamination factor of the radionuclide, prolong the service life of the ion exchange bed, and greatly reduce the amount of radioactive solid waste. .

If the pollution index SDI in the radioactive waste water is less than 2, the activated carbon adsorption process may not be provided.

If the Cs ⁺ ion content in the radioactive waste water is less than 10 ⁵ Bq/L, the helium adsorption process may not be provided.

The above is only a specific embodiment of the present application, and it should be understood that the scope of protection of the present application is not limited thereto, and any person skilled in the art can easily think of various kinds within the technical scope disclosed in the present application. Modifications or substitutions are intended to be included within the scope of the present application.

Claims (22)

A method of treating a radioactive waste liquid, wherein the method comprises: Separating the radioactive waste liquid to obtain a first purification liquid and a concentrated liquid; Performing an ion exchange treatment on the concentrated liquid to obtain a second purification liquid; Wherein the first purification liquid and the second purification liquid are discharged; or the second purification liquid is returned to the separation treatment step, and the first purification liquid is discharged; or The second purification liquid is returned to the separation treatment step, and the first purification liquid and the remaining portion of the second purification liquid are discharged. The method according to claim 1, wherein the separation treatment employs one or a combination of two or more of a nanofiltration process, a reverse osmosis process, and a continuous electric desalination process. The method according to claim 1, wherein said separating the radioactive waste liquid to obtain the first purified liquid and the concentrated liquid comprises: treating the radioactive waste liquid by a one-stage or two-stage reverse osmosis process. The method according to claim 3, wherein each of said reverse osmosis processes employs one or two or more stages of reverse osmosis treatment, and when two or more stages of reverse osmosis are used, the upper stage of reverse osmosis treatment is used as In the next stage of reverse osmosis treatment, the purified liquid is sent from each section to the purification liquid of the reverse osmosis process. The method of claim 3 wherein said two-stage reverse osmosis process comprises: The radioactive waste liquid is sequentially processed through the first-stage reverse osmosis process and the second-stage reverse osmosis process, and the second-stage reverse osmosis concentrate sent from the second-stage reverse osmosis process is returned to the first-stage reverse osmosis process. The first stage reverse osmosis process delivers the concentrate. The method according to claim 3, wherein after the treating the radioactive waste liquid through the one-stage or two-stage reverse osmosis process, the method further comprises: passing the purified liquid obtained by the first-stage or two-stage reverse osmosis process through a Class or two-stage continuous electric desalination process. The method of claim 6 wherein said two-stage continuous electrical desalination process comprises: The purified liquid obtained by the first-stage or two-stage reverse osmosis process is sequentially subjected to a first-stage continuous electric desalination process and a second-stage continuous electric desalination process to obtain the first purified liquid; the first stage The first-stage continuous electric desalting concentrate sent by the continuous electric desalination process and the second-stage continuous electric desalting concentrate sent by the second-stage continuous electric desalination process are returned to the first-stage or two-stage reverse osmosis process. The method according to claim 7, wherein an activator is added to the intermediate cleaning liquid sent from the first-stage continuous electric desalination process, and then sent to the second-stage continuous electric desalination process. The method according to claim 1, wherein the volume of the radioactive waste liquid is more than twice the volume of the concentrated liquid, and the concentration of the radionuclide in the concentrated liquid is a radionuclide in the radioactive waste liquid. The concentration is more than 2 times. The method according to claim 1, wherein the radioactive waste liquid is subjected to pretreatment to remove one or more of oils, colloids, particulate matter, sputum, sputum, and/or adjustment before performing the separation treatment. pH value. The method according to claim 10, wherein in the radioactive waste liquid, when the activity of cesium, the activity of strontium, and the total activity of strontium and strontium are 10 ⁵ Bq/L or more Pretreatment to remove ruthenium and/or ruthenium is required. A radioactive waste liquid processing apparatus, wherein the apparatus comprises a separation unit, an ion exchange unit, and a drainage unit, wherein a concentrate outlet of the separation unit is connected to an inlet of the ion exchange unit; a purification liquid outlet of the separation unit is connected to the drainage unit; The purge liquid outlet of the ion exchange unit is connected to the drain unit and/or the inlet of the separation unit. The apparatus according to claim 12, wherein the separation unit comprises one of a nanofiltration unit, a reverse osmosis subunit, a continuous electric desalting subunit, or a combination of two or more. The apparatus of claim 13 wherein said separation unit comprises a reverse osmosis subunit, and wherein said reverse osmosis subunit comprises a primary or secondary reverse osmosis apparatus. The apparatus according to claim 14, wherein said separation unit further comprises a continuous electric desalting subunit, said reverse osmosis subunit and said continuous electric desalting subunit being sequentially connected; wherein said continuous electric desalination The subunits include one or two stages of continuous electric desalination equipment. The apparatus according to claim 14 or 15, wherein said reverse osmosis apparatus employs a reverse osmosis membrane module or two or more reverse osmosis membrane modules in series, and when two or more reverse osmosis membrane modules are used, the upper one is reversed. The concentrate outlet of the permeable membrane module is connected to the inlet of the next reverse osmosis membrane module. The apparatus according to claim 14 or 15, wherein said reverse osmosis subunit comprises a primary reverse osmosis device, and said concentrate outlet of said reverse osmosis device is divided into two branches via a pipe, one branch and said The inlet of the reverse osmosis device is connected, and the other branch is connected to the inlet of the ion exchange unit; or The reverse osmosis subunit comprises a two-stage reverse osmosis device, wherein the concentrate outlet of the first stage reverse osmosis device is divided into two branches via a pipeline, one branch is connected to the inlet of the first stage reverse osmosis device, and the other branch is connected The road is connected to the inlet of the ion exchange unit. The apparatus according to claim 14 or 15, wherein said reverse osmosis subunit comprises a two-stage reverse osmosis apparatus, wherein a purge liquid outlet of the first stage reverse osmosis apparatus is connected to an inlet of the second stage reverse osmosis apparatus, The concentrate outlet of the secondary reverse osmosis apparatus is connected to the inlet of the first stage reverse osmosis apparatus, and the concentrate outlet of the first stage reverse osmosis apparatus is connected to the inlet of the ion exchange unit. The apparatus according to claim 15, wherein said continuous electric desalination subunit comprises a two-stage continuous electric desalination apparatus, wherein said purification liquid outlet of said reverse osmosis subunit is continuously deionized with said first stage The inlet of the device is connected, the outlet of the purification liquid of the first-stage continuous electric desalination device is connected to the inlet of the second-stage continuous electric desalination device, and the outlet of the purification liquid of the second-stage continuous electric desalination device is connected to The drain unit, the concentrate outlet of the first stage continuous electric desalination apparatus and the concentrate outlet of the second stage continuous electric desalination apparatus are respectively connected to the inlet of the reverse osmosis subunit. The apparatus according to claim 19, wherein said purification liquid outlet of said first-stage continuous electric desalination apparatus is connected to an inlet of said second-stage continuous electric desalination apparatus via an intermediate water tank, said intermediate water tank and activator The boxes are connected. The apparatus of claim 12 wherein said ion exchange unit comprises one or more stages of ion exchangers. The apparatus according to claim 12, wherein the apparatus further comprises a pre-processing unit connected to the inlet of the separation unit for removing oil, colloid, particulate matter, hydrazine in the radioactive waste liquid, More than one of the sputum, and / or, adjust the pH.

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