Device for detecting precipitation reaction in real time by square wave volt-ampere method

Abstract

The utility model belongs to the technical field of nuclear waste treatment, and particularly relates to a device for detecting precipitation reaction in real time by a square wave volt-ampere method, which comprises a shell, a corundum crucible, a corundum sleeve, a corundum top cover, a reference electrode, a counter electrode, a working electrode and a thermocouple, the corundum sleeve is arranged in the shell, the corundum crucible is arranged in the corundum sleeve, the corundum top cover seals an opening in the upper end of the shell, a reference electrode hole, a counter electrode hole, a working electrode hole and a thermocouple hole are formed in the corundum top cover, and a reference electrode penetrates through the reference electrode hole and then is inserted into the corundum crucible. The counter electrode penetrates through the counter electrode hole and then is inserted into the corundum crucible, the working electrode penetrates through the working electrode hole and then is inserted into the corundum crucible, and the thermocouple penetrates through the thermocouple hole and then is inserted into the corundum crucible; the corundum top cover is further provided with an argon inlet which is connected with an argon source through a pipeline. By using the device, accurate detection is realized, and the content of rare earth ions in the final soluble salt is greatly reduced.

Description

Technical Field

[0001] This invention belongs to the field of nuclear waste treatment technology, specifically relating to a device for real-time detection of precipitation reactions using a square wave voltammetry method. Background Technology

[0002] While nuclear energy development generates enormous profits, it inevitably produces some radioactive nuclear waste. Currently, there are two ways to dispose of nuclear waste: one is to establish a suitable underground storage facility to bury the nuclear waste directly underground; the other is to recover valuable elements such as uranium and plutonium from the nuclear waste, convert the remaining high-radioactivity waste into a suitable form for solidification and temporary storage, and then dispose of it underground.

[0003] Currently, the main methods for solidifying radioactive waste include the glass method, the asphalt method, the cement method, and the ceramic method. Among these, glass substrates have the advantages of large containment capacity for radioactive waste, more stable chemical properties, reasonable melting temperature, significant shielding effect against radiation, and easy component design, making them the preferred solidification material for high-level radioactive waste.

[0004] However, dry post-processing methods such as glassmaking leave behind fission products such as rare earth elements and actinides in the molten salt. Rare earth elements account for about 1 / 4 of the fission products and have a high thermal neutron capture cross section, so they are called neutron poisons. Therefore, rare earth elements must be removed to allow the molten salt to be recycled. Thus, detecting the concentration of residual rare earth ions in the molten salt during the precipitation reaction is a research topic in this field. Utility Model Content

[0005] The purpose of this invention is to provide a device for real-time detection of precipitation reactions using a square wave voltammetry method, which can detect residual rare earth ions in molten salt in real time, providing guidance for the vitrification process of precipitation.

[0006] To achieve the above objectives, this application employs the following technical solution:

[0007] A device for real-time detection of precipitation reaction using square wave voltammetry includes a shell, a corundum crucible, a corundum sleeve, a corundum top cover, a reference electrode, a counter electrode, a working electrode, and a thermocouple.

[0008] The corundum sleeve is disposed inside the outer shell, the corundum crucible is disposed inside the corundum sleeve, and the corundum top cover closes the upper opening of the outer shell. The corundum top cover is provided with a reference electrode hole, a counter electrode hole, a working electrode hole, and a thermocouple hole. The reference electrode passes through the reference electrode hole and is inserted into the corundum crucible. The counter electrode passes through the counter electrode hole and is inserted into the corundum crucible. The working electrode passes through the working electrode hole and is inserted into the corundum crucible. The thermocouple passes through the thermocouple hole and is inserted into the corundum crucible.

[0009] An argon inlet is also provided on the corundum top cover, which is connected to an argon source through a pipeline.

[0010] Furthermore, the reference electrode is positioned between the working electrode and the counter electrode.

[0011] Furthermore, the working electrode is an inert cathode tungsten wire with a diameter of 1.0 mm.

[0012] Furthermore, the working electrode is covered with a corundum double-hole tube.

[0013] Furthermore, the counter electrode is a spectrally pure graphite rod with a diameter of 6.0 mm.

[0014] Furthermore, a quartz tube is used as a casing for the counter electrode.

[0015] Furthermore, the reference electrode includes an alumina tube and a silver wire, the silver wire being disposed inside the alumina tube with one end extending out of the alumina tube, and a chloride salt being disposed inside the alumina tube.

[0016] Furthermore, the silver wire includes a silver wire body and a spiral coiled portion disposed at the bottom end of the silver wire body.

[0017] Furthermore, the length of the spiral curled portion is 1 cm.

[0018] The beneficial effects of this utility model are:

[0019] In this technical solution, the positions of the oxidation and reduction peaks of rare earth elements are first determined using cyclic voltammetry during the precipitation reaction. Then, the concentration of rare earth ions is monitored in real time using square wave voltammetry. When no rare earth ions are detected, precipitation is considered complete, and the molten salt after the precipitation reaction is vitrified. This technical solution achieves accurate detection and significantly reduces the content of rare earth ions in the final molten salt. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the device for real-time detection of precipitation reactions according to this invention.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1. Reference electrode; 2. Counter electrode; 3. Working electrode; 4. Thermocouple; 5. Argon inlet; 6. Corundum top cover; 7. Corundum sleeve; 8. Corundum crucible; 9. Molten salt; 10. Outer shell; 11. Corundum tube; 21. Quartz tube. Detailed Implementation

[0023] The technical solution of this utility model will be described in detail below with reference to the accompanying drawings. The following embodiments are merely exemplary and can only be used to explain and illustrate the technical solution of this utility model, and should not be construed as limiting the technical solution of this utility model.

[0024] like Figure 1 As shown, this application provides an apparatus for real-time detection of precipitation reactions using a square wave voltammetry method, comprising a shell 10, a corundum crucible 8, a corundum sleeve 7, a corundum top cover 6, a reference electrode 1, a counter electrode 2, a working electrode 3, and a thermocouple 4.

[0025] The outer shell 10 of this application is a cup-shaped structure with a bottom, and its material is a material of conventional technology. The outer shell has a cylindrical structure. The corundum sleeve is disposed inside the outer shell, and the corundum sleeve 7 of this application is cylindrical.

[0026] The corundum crucible 8 is disposed inside the corundum sleeve 7. In this application, the corundum crucible has an inverted frustum-shaped structure with an upper opening larger than the bottom. The inner diameter of the corundum sleeve is provided with a step, wherein the lower inner diameter is larger than the upper inner diameter, and the step abuts against the upper end face of the corundum crucible. This can reduce the corrosion of the outer shell by chlorine gas generated during electrochemical measurements.

[0027] The corundum top cover 6 closes the upper opening of the outer shell. In this application, the upper surface of the corundum sleeve is slightly lower than the upper surface of the outer shell. This structure is conducive to the overall sealing of the device.

[0028] The corundum top cover is provided with a reference electrode hole, a counter electrode hole, a working electrode hole, and a thermocouple hole. The reference electrode passes through the reference electrode hole and is inserted into the corundum crucible. The counter electrode passes through the counter electrode hole and is inserted into the corundum crucible. The working electrode passes through the working electrode hole and is inserted into the corundum crucible. The thermocouple passes through the thermocouple hole and is inserted into the corundum crucible. In addition, a sealing element is provided at the position opposite to each electrode and the corundum top cover to seal the device. The sealing element is made of the sealing material used in the current technology.

[0029] An argon inlet 5 is also provided on the corundum top cover, which is connected to an argon source through a pipeline.

[0030] In this application, the reference electrode is positioned between the working electrode and the counter electrode. This arrangement ensures accurate detection. In other embodiments of this application, the reference electrode, counter electrode, and working electrode may also be arranged in an equilateral triangle.

[0031] In this application, the working electrode 3 is an inert cathode tungsten wire with a diameter of 1.0 mm. In order to avoid corrosion of the working electrode, a corundum double-hole tube is used as a jacket for the working electrode.

[0032] In this application, the counter electrode 2 is a spectrally pure graphite rod with a diameter of 6.0 mm. To avoid corrosion of the counter electrode, a quartz tube 21 is used as a casing for the counter electrode.

[0033] In this application, the reference electrode 1 includes a corundum tube 11 and a silver wire. The silver wire is disposed inside the corundum tube, with one end extending out of the corundum tube. A chloride salt is disposed inside the corundum tube. The silver wire includes a silver wire body and a spirally coiled portion disposed at the bottom end of the silver wire body. The length of the spirally coiled portion is 1 cm to increase the contact area.

[0034] How this application works:

[0035] The testing method using this device in this application is a square wave voltammetry test method, which is a conventional test method. Since this technical solution does not involve how to perform square wave voltammetry testing, the square wave voltammetry test method will not be described.

[0036] Before testing, this application also requires a step of purifying the molten salt, specifically including the pretreatment of the molten salt and the chlorination of rare earth oxides. The above steps are all existing technologies, and this technical solution does not involve these steps, so they will not be described in detail.

[0037] The working electrode of this application needs to be polished and cleaned with hydrofluoric acid, ethanol or acetone before use, and then dried for later use. The auxiliary electrode is cleaned with dilute hydrochloric acid.

[0038] A lithium chloride-potassium chloride molten salt containing DyCl3 is added to the device, and then a precipitant is used for precipitation. After each addition of the precipitant, the concentration of rare earth Dy is detected by square wave voltammetry (frequency 20 Hz). When no rare earth ions are detected, the precipitation reaction is complete, and the subsequent vitrification production can proceed.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. An apparatus for real-time detection of precipitation reactions using square wave voltammetry, characterized in that, It includes an outer shell, a corundum crucible, a corundum sleeve, a corundum top cover, a reference electrode, a counter electrode, a working electrode, and a thermocouple; The corundum sleeve is disposed inside the outer shell, the corundum crucible is disposed inside the corundum sleeve, and the corundum top cover closes the upper opening of the outer shell. The corundum top cover is provided with a reference electrode hole, a counter electrode hole, a working electrode hole, and a thermocouple hole. The reference electrode passes through the reference electrode hole and is inserted into the corundum crucible. The counter electrode passes through the counter electrode hole and is inserted into the corundum crucible. The working electrode passes through the working electrode hole and is inserted into the corundum crucible. The thermocouple passes through the thermocouple hole and is inserted into the corundum crucible. An argon inlet is also provided on the corundum top cover, which is connected to an argon source through a pipeline.

2. The apparatus for real-time detection of precipitation reactions using the square wave voltammetry method according to claim 1, characterized in that, The reference electrode is positioned between the working electrode and the counter electrode.

3. The apparatus for real-time detection of precipitation reactions using the square wave voltammetry method according to claim 1, characterized in that, The working electrode is an inert cathode tungsten wire with a diameter of 1.0 mm.

4. The apparatus for real-time detection of precipitation reactions using the square wave voltammetry method according to claim 3, characterized in that, The working electrode is covered with a corundum double-hole tube.

5. The apparatus for real-time detection of precipitation reactions using the square wave voltammetry method according to claim 1, characterized in that, The counter electrode is a spectrally pure graphite rod with a diameter of 6.0 mm.

6. The apparatus for real-time detection of precipitation reactions using the square wave voltammetry method according to claim 5, characterized in that, A quartz tube is placed over the counter electrode.

7. The apparatus for real-time detection of precipitation reactions using the square wave voltammetry method according to claim 1, characterized in that, The reference electrode includes an alumina tube and a silver wire. The silver wire is disposed inside the alumina tube, with one end extending out of the alumina tube. A chloride salt is disposed inside the alumina tube.

8. The apparatus for real-time detection of precipitation reactions using the square wave voltammetry method according to claim 7, characterized in that, The silver wire includes a silver wire body and a spiral coiled portion disposed at the bottom end of the silver wire body.

9. The apparatus for real-time detection of precipitation reactions using the square wave voltammetry method according to claim 8, characterized in that, The length of the spiral curled portion is 1 cm.

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