Method for controlling morphology of ruthenium oxide precipitate in high-level liquid waste glass curing process

Abstract

The invention relates to the technical field of radioactive waste solidification treatment, and provides a method for controlling ruthenium oxide (RuO2) precipitate morphology in a high-level liquid waste glass solidification process, and the method comprises the following steps: S1, mixing glass raw materials, heating and melting, cooling, and crushing to prepare 1-2 mm basic glass particles; s2, a nitrate reagent is dissolved in nitric acid, simulated high-level radioactive waste liquid with the nitric acid concentration being 1-8 mol / L is prepared, and dried simulated high-level radioactive waste is obtained after evaporation drying; s3, mixing the basic glass with the dried simulated high-level radioactive waste, heating and melting, and cooling to obtain a glass solidified body sample. The RuO2 morphology control is realized by regulating and simulating the concentration of nitric acid in the high-level liquid waste: in the step S2, when the concentration of the nitric acid is 1-3 mol / L, short rod-shaped and granular RuO2 crystals are mainly separated out from a solidified body; and when the concentration of the nitric acid is 3-8 mol / L, forming a long needle-shaped RuO2 crystal. In addition, the simulated high-level radioactive waste which is dried by distillation is calcined at 650-850 DEG C, so that more granular RuO2 crystals can be obtained or needle-shaped RuO2 can be converted into particles.

Description

Technical Field

[0001] This invention relates to the field of radioactive waste solidification treatment technology, and in particular to a method for controlling the morphology of ruthenium oxide precipitates during the glass solidification process of high-level radioactive waste liquid. Background Technology

[0002] Nuclear energy occupies a vital strategic position in my country's energy system, and its safe utilization is directly related to national energy security and national defense. my country adopts a closed nuclear fuel cycle, in which the reprocessing of spent fuel inevitably generates high-level radioactive waste. This waste possesses extremely high biotoxicity and radioactivity, posing a significant threat to the ecological environment. It typically requires vitrification followed by deep geological treatment to achieve maximum isolation from the biosphere. Vitrification refers to the technique of evaporating, calcining, and melting the high-level radioactive waste with a glass substrate at high temperatures, then casting it into a stable vitrified body. Vitrified bodies are resistant to leaching, radiation, and have a wide elemental tolerance. Their production is easily controlled remotely, making it currently the only high-level radioactive waste solidification treatment technology in the world to achieve engineering applications.

[0003] However, the platinum group metals ruthenium (Ru), rhodium (Rh), and palladium (Pd) contained in high-level radioactive waste liquids have extremely low solubility (<100 ppm), high melting points (>2000 ℃), and stable chemical properties in borosilicate glass, making them highly susceptible to precipitation and stable existence in the glass melt. The density of platinum group metals and their oxides is 7~13 g / cm³. 3 It is much higher than the density of glass melt (~2.5 g / cm³). 3 During long-term continuous operation of the furnace, platinum group metals and their oxide particles gradually grow, settle, and accumulate at the bottom of the molten pool, eventually forming a sludge-like glass melt rich in platinum group metals. When the platinum group metal content in the "sludge" exceeds 15 wt%, its resistivity is more than 20 times lower than that of normal glass melt, easily causing excessively high local current density at the bottom of the furnace, resulting in operational interruptions; while its viscosity is generally nearly 10 times higher than that of normal melt, easily leading to operational failures such as poor discharge and blockage of the discharge port. Ru has the highest proportion among the three platinum group metals (usually greater than 50%), and its precipitates have the greatest impact on the properties of the glass melt. During glass solidification, Ru precipitates mainly in the form of granular, short rod-shaped, or long needle-shaped ruthenium oxide (RuO2), and the effects of RuO2 with different morphologies on the properties of the glass melt vary significantly.

[0004] Regarding methods for controlling the morphology of ruthenium oxide precipitates during the vitrification process of high-level radioactive waste, existing patent 202211408096.6 discloses a method for improving the deposition of precious metals in a vitrified body and its preparation. By introducing a small amount of P2O5 and Fe2O3 into borosilicate glass, the RuO2 precipitates are made granular, improving the glass melt performance and thus extending the life of the glass curing furnace. However, the additional P and Fe elements introduced by this technical solution change the chemical composition of the final cured body, posing challenges to its practical application. For example, the introduction of P easily induces phase separation in borosilicate glass, reducing chemical stability; while Fe easily forms a refractory spinel phase with elements such as Mg, Ni, and Cr in the high-level radioactive waste liquid during the glass curing process, clogging the discharge port and bringing new challenges. Another patent application, 202410981499.2, discloses a method for suppressing needle-like platinum group metal precipitation during the glass curing process of high-level radioactive waste liquid. It proposes to suppress needle-like platinum group metal precipitation by controlling the base glass particle size (0.05–0.90 mm), promoting the dispersion of platinum group metals as fine, uniform particles in the glass matrix, thereby reducing the impact of platinum group metal precipitates on the glass melt properties. However, in actual glass curing processes, to ensure smooth pipeline operation and continuous feeding, the glass particle size is generally required to be 1–3 mm. Particle sizes that are too large or too small will affect the normal operation of the process. Therefore, a practical and feasible method for controlling the morphology of RuO2 precipitates needs to be developed. Summary of the Invention

[0005] In view of this, the present invention proposes a method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid, so as to solve the problems of reduced chemical stability of glass-cured body and difficult process operation caused by existing methods for improving precious metal precipitation during the glass curing process of high-level radioactive waste liquid.

[0006] The technical solution of this invention is achieved as follows: On one hand, this invention provides a method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid, comprising the following steps: S1. Mix the glass raw materials, heat and melt them, then cool and crush them to obtain basic glass particles with a particle size of 1–2 mm; S2. Dissolve the nitrate reagent in nitric acid to prepare a simulated high-level radioactive waste liquid with a nitric acid concentration of 1~8 mol / L. After evaporation, dry simulated high-level radioactive waste is obtained. S3. The base glass is mixed with dry simulated high-level radioactive waste, heated and melted, and then cooled to obtain a glass-cured sample.

[0007] Specifically, this invention controls the morphology of ruthenium oxide precipitates during the glass curing process of simulated high-level radioactive waste by adjusting the nitric acid concentration in the simulated high-level radioactive waste solution without altering its chemical composition. When the nitric acid concentration in the simulated high-level radioactive waste solution is 3-8 mol / L, nitrogen oxides (NOx)... x The release of RuO2 precursors (such as RuO2) increases sharply, forming numerous porous channels and promoting the release of RuO2 precursors (such as RuO2). 3+ Nucleation occurs along the surface of the pore channels; simultaneously, NO... x Release causes localized expansion of the melt, disrupting structural continuity and creating low-resistance growth spaces. Increased porosity enhances mass transfer directionality; the axial diffusion rate of the RuO2 precursor within the pores is significantly higher than the radial rate, driving preferential axial crystal growth and accelerating RuO2 nucleation and extension along the interface, forming long needle-like crystals. Conversely, when the nitric acid concentration in the simulated high-level radioactive waste is 1–3 mol / L, the reduced porosity between the basic glass particles and the waste restricts RuO2 precipitate growth, making it difficult for long needle-like crystals to form, primarily resulting in short rod-shaped and granular RuO2 crystals. When the nitric acid concentration in the simulated high-level radioactive waste exceeds 8 mol / L, its strong acidity accelerates corrosion of the feed and exhaust gas pipelines, shortening equipment lifespan. In spent fuel reprocessing, the nitric acid concentration in high-level radioactive waste is typically greater than 1 mol / L and fluctuates with different process stages.

[0008] Based on the above technical solutions, in order to obtain more granular RuO2 crystals or transform needle-like RuO2 into granular form, the simulated high-level radioactive waste dried in step S2 is first calcined at 650~850 ℃ for 1.0~5.0 h, and then mixed with the base glass. The calcination process is as follows: the dried simulated high-level radioactive waste is placed in a muffle furnace, heated to the target temperature and held at that temperature, and finally cooled to room temperature with the furnace before being removed.

[0009] Specifically, the simulated high-level radioactive waste, after being dried, can achieve partial denitrification through calcination pretreatment. During the calcination process, nitrates are thermally decomposed in advance, releasing nitrogen oxide gases, effectively eliminating the gas source for the subsequent glass curing process. When the calcined waste is mixed and melted with the base glass, the amount of bubbles generated inside the melt is significantly reduced, the melt structure has good continuity, the axial growth process of RuO2 crystals is hindered, and ultimately a granular RuO2 crystal structure is mainly formed, resulting in increased resistivity and decreased viscosity.

[0010] Based on the above technical solutions, preferably, in step S3, the content of the base glass is 70~90 wt% and the content of the simulated high-level radioactive waste is 10~30 wt% by mass percentage of oxides.

[0011] Based on the above technical solutions, preferably, in step S1, the chemical composition of the glass raw material includes multiple of SiO2, B2O3, Al2O3, CaO, Na2O, Li2O and ZrO2.

[0012] Based on the above technical solutions, preferably, the content of SiO2 in the base glass is 40 wt%~60 wt%, the content of B2O3 is 10 wt%~20 wt%, the content of Al2O3 is 2 wt%~10 wt%, the content of CaO is 1 wt%~25 wt%, the content of Na2O is 9 wt%~26 wt%, the content of Li2O is 1 wt%~5 wt%, and the content of ZrO2 is 1 wt%~4 wt%, based on the mass percentage of oxides.

[0013] In this invention, SiO2 serves as the main network forging agent for the glass, and its content determines the overall stability of the glass structure; B2O3, as a glass network forging agent, can reduce the coefficient of thermal expansion of the glass and improve its thermal and chemical stability; Al2O3 can enhance the glass's acid resistance and high-temperature resistance; CaO, as an alkaline earth metal oxide, can improve the glass's water resistance and chemical corrosion resistance; and Li2O and Na2O, two alkali metal oxides, are beneficial for improving the glass's melting efficiency and processability.

[0014] Based on the above technical solutions, preferably, the chemical composition of the simulated high-level radioactive waste liquid includes multiple substances selected from RuO2, Na2O, ZrO2, MoO3, Nd2O3, CeO2, La2O3, Pr2O3, Sm2O3, Y2O3, Gd2O3, Eu2O3, Cs2O, BaO, Fe2O3, Cr2O3, NiO, SrO, and SnO2.

[0015] Based on the above technical solutions, preferably, the simulated high-level radioactive waste contains RuO2 at a content of 2 wt% to 10 wt%, Na2O at a content of 8 wt% to 34 wt%, ZrO2 at a content of 5 wt% to 20 wt%, MoO3 at a content of 10 wt% to 20 wt%, and the total content of rare earth element oxides at a content of 20 wt% to 45 wt%, with the content of other components all greater than 0; the rare earth element oxides are one or more of Nd2O3, CeO2, La2O3, Pr2O3, Sm2O3, Y2O3, Gd2O3, and Eu2O3.

[0016] Based on the above technical solutions, preferably, the simulated high-level radioactive waste glass solidified body contains, by mass percentage of oxides, 28 wt%~54 wt% SiO2, 7 wt%~18 wt% B2O3, 1.4 wt%~9 wt% Al2O3, 0.7 wt%~22.5 wt% CaO, 0.7 wt%~4.5 wt% Li2O, 8.7 wt%~28.4 wt% Na2O, 0.2 wt%~3 wt% RuO2, 1.4 wt%~8.8 wt% ZrO2, 1 wt%~4 wt% MoO3, and 2 wt%~13.5 wt% rare earth element oxides. The content of other components is greater than 0 wt%; the rare earth element oxides are one or more of Nd2O3, CeO2, La2O3, Pr2O3, Sm2O3, Y2O3, Gd2O3, and Eu2O3.

[0017] Based on the above technical solutions, preferably, in steps S1 and S3, the heating and melting temperature is 1100~1200℃; in step S2, the evaporation and drying temperature is 150~200℃.

[0018] On the other hand, the present invention also provides a glassy solidified body simulating high-level radioactive waste liquid, which is prepared by the above-described method.

[0019] The method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid according to the present invention has the following advantages over the prior art: (1) By adjusting the concentration of nitric acid in the simulated high-level radioactive waste liquid, the morphology of ruthenium oxide precipitates during the glass curing process of the simulated high-level radioactive waste liquid is controlled. This method does not change the chemical composition and properties of the high-level radioactive glass curing body and has wide applicability to different glass curing processes.

[0020] (2) The present invention also proposes a technical route for first calcining and denitrifying high-level radioactive waste liquid to remove excess nitrate, and then mixing and melting it with basic glass to obtain more particulate ruthenium oxide precipitates. The process is feasible and has good engineering application prospects. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1This is a SEM image of the high-level radioactive waste liquid vitrified body prepared in Example 1 of the present invention; Figure 2 This is a SEM image of the high-level radioactive waste liquid vitrified body prepared in Example 3 of the present invention; Figure 3 This is a SEM image of the high-level radioactive waste liquid vitrified body prepared in Example 5 of the present invention; Figure 4 This is a SEM image of the high-level radioactive waste liquid vitrified body prepared in Example 8 of the present invention; Figure 5 This is a SEM image of the high-level radioactive waste liquid glass solidified body prepared in Example 9 of the present invention. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1

[0025] This embodiment provides a method for controlling the morphology of ruthenium oxide precipitates during the vitrification process of high-level radioactive waste. The design composition of the Ru-containing simulated high-level radioactive waste vitrified body is shown in Table 1. The specific steps are as follows: (1) Weigh the borosilicate glass raw materials and mix them evenly, wherein SiO2, B2O3, Al2O3 and ZrO2 are introduced in the form of oxides, and CaO, Na2O and Li2O are introduced in the form of carbonates; (2) Place 60 g of mixed glass raw material in a corundum crucible and heat it in a muffle furnace at 1200 °C for 1 h. After taking out the glass liquid, let it cool naturally on a copper plate. Then crush and sieve to obtain borosilicate basic glass particles with a particle size of 1~2 mm. (3) Weigh the simulated high-level radioactive waste liquid raw material, dissolve it in 3 mol / L nitric acid solution, prepare simulated high-level radioactive waste liquid containing Ru, wherein MoO3 is introduced in the form of molybdate, and the remaining components are introduced in the form of nitrate. Then, the simulated high-level radioactive waste is obtained by evaporation at 200 °C. (4) Mix the basic glass particles with the Ru-containing simulated high-level radioactive waste according to the target ratio, take 10 g of the mixture and place it in a corundum crucible, heat and melt it in a muffle furnace at 1200 ℃ for 1 h, take it out and cool it naturally at room temperature to finally obtain the Ru-containing simulated glass solidified sample.

[0026] Table 1. Design composition (wt%) of Ru-containing simulated high-level radioactive glass curing bodies

[0027] Example 2 This embodiment provides a method for controlling the morphology of ruthenium oxide precipitates during the vitrification process of high-level radioactive waste. The design composition of the Ru-containing simulated high-level radioactive waste vitrified body is shown in Table 2. The specific steps are as follows: (1) Weigh the borosilicate glass raw materials and mix them evenly, wherein SiO2, B2O3, Al2O3 and ZrO2 are introduced in the form of oxides, and CaO, Na2O and Li2O are introduced in the form of carbonates; (2) Place 60 g of mixed glass raw material in a corundum crucible and heat it in a muffle furnace at 1200 ℃ for 0.5 h. After taking out the glass liquid, let it cool naturally on a copper plate, then crush and sieve it to obtain borosilicate basic glass particles with a particle size of 1~2 mm. (3) Weigh the simulated high-level radioactive waste liquid raw material, dissolve it in 3 mol / L nitric acid solution, prepare simulated high-level radioactive waste liquid containing Ru, wherein MoO3 is introduced in the form of molybdate, and the remaining components are introduced in the form of nitrate. Then, the simulated high-level radioactive waste is obtained by evaporation at 150 °C. (4) Mix the basic glass particles with the Ru-containing simulated high-level radioactive waste according to the target ratio, take 10 g of the mixture and place it in a corundum crucible, heat and melt it in a muffle furnace at 1200 ℃ for 0.5 h, take it out and let it cool naturally at room temperature to finally obtain the Ru-containing simulated glass solidified sample.

[0028] Table 2. Design composition (wt%) of Ru-containing simulated high-level radioactive glass curing bodies

[0029] Example 3 This embodiment provides a method for controlling the morphology of ruthenium oxide precipitates during the vitrification process of high-level radioactive waste. The design composition of the Ru-containing simulated high-level radioactive waste vitrified body is shown in Table 3. The specific steps are as follows: (1) Weigh the borosilicate glass raw materials and mix them evenly, wherein SiO2, B2O3, Al2O3 and ZrO2 are introduced in the form of oxides, and CaO, Na2O and Li2O are introduced in the form of carbonates; (2) Place 60 g of mixed glass raw material in a corundum crucible and heat it in a muffle furnace at 1150 °C for 1 h. After taking out the glass liquid, let it cool naturally on a copper plate. Then crush and sieve to obtain borosilicate basic glass particles with a particle size of 1~2 mm. (3) Weigh the simulated high-level radioactive waste liquid raw material, dissolve it in 1 mol / L nitric acid solution, prepare simulated high-level radioactive waste liquid containing Ru, wherein MoO3 is introduced in the form of molybdate, and the remaining components are introduced in the form of nitrate. Then, the simulated high-level radioactive waste is obtained by evaporation at 200 °C. (4) Mix the basic glass particles with the Ru-containing simulated high-level radioactive waste according to the target ratio, take 10 g of the mixture and place it in a corundum crucible, heat and melt it in a muffle furnace at 1150 ℃ for 0.5 h, take it out and let it cool naturally at room temperature to finally obtain the Ru-containing simulated glass solidified sample.

[0030] Table 3. Design composition (wt%) of Ru-containing simulated high-level radioactive glass curing bodies

[0031] Example 4 This embodiment provides a method for controlling the morphology of ruthenium oxide precipitates during the vitrification process of high-level radioactive waste. The design composition of the Ru-containing simulated high-level radioactive waste vitrified body is shown in Table 4. The specific steps are as follows: (1) Weigh the borosilicate glass raw materials and mix them evenly, wherein SiO2, B2O3, Al2O3 and ZrO2 are introduced in the form of oxides, and CaO, Na2O and Li2O are introduced in the form of carbonates; (2) Place 60 g of mixed glass raw material in a corundum crucible and heat it in a muffle furnace at 1100 °C for 1 h. After taking out the glass liquid, let it cool naturally on a copper plate. Then crush and sieve to obtain borosilicate basic glass particles with a particle size of 1~2 mm. (3) Weigh the simulated high-level radioactive waste liquid raw material, dissolve it in 1 mol / L nitric acid solution, prepare simulated high-level radioactive waste liquid containing Ru, wherein MoO3 is introduced in the form of molybdate, and the remaining components are introduced in the form of nitrate. Then, the simulated high-level radioactive waste is obtained by evaporation at 200 °C. (4) Mix the basic glass particles with the Ru-containing simulated high-level radioactive waste according to the target ratio, take 10 g of the mixture and place it in a corundum crucible, heat and melt it in a muffle furnace at 1100 ℃ for 1 h, take it out and cool it naturally at room temperature to finally obtain the Ru-containing simulated glass solidified sample.

[0032] Table 4. Design composition (wt%) of Ru-containing simulated high-level radioactive glass curing bodies

[0033] Example 5 This embodiment provides a method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid. The specific operation is as follows: based on Example 1, a calcination step is added. This step includes placing the simulated high-level radioactive waste that has been evaporated in step (3) into a muffle furnace, heating it to 750 ℃ ​​with the furnace, holding it at that temperature for 3 h, then cooling it to room temperature with the furnace, and finally mixing it with the base glass.

[0034] Example 6

[0035] This embodiment provides a method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid. The specific operation is the same as in embodiment 5, except that: in the calcination step, the simulated high-level radioactive waste after evaporation is placed in a muffle furnace, heated to 850 ℃ with the furnace, kept at that temperature for 1 h, and then cooled to room temperature with the furnace before being mixed with the base glass.

[0036] Example 7

[0037] This embodiment provides a method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid. The specific operation is the same as in embodiment 5, except that: in the calcination step, the simulated high-level radioactive waste after evaporation is placed in a muffle furnace, heated to 650 ℃ with the furnace, kept at that temperature for 5 h, and then cooled to room temperature with the furnace before being mixed with the base glass.

[0038] Example 8

[0039] This embodiment provides a method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid. The specific operation is the same as in Embodiment 1, except that the concentration of the nitric acid solution is 5 mol / L.

[0040] Example 9

[0041] This embodiment provides a method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid. The specific operation is the same as in Embodiment 1, except that the concentration of the nitric acid solution is 8 mol / L.

[0042] Comparative Example 1 This comparative example provides a method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid. The specific operation is the same as in Example 1, except that in step (3), the simulated high-level radioactive waste liquid raw material is dissolved in 10 mol / L nitric acid solution to prepare a simulated high-level radioactive waste liquid containing Ru.

[0043] The high concentration of nitric acid in the waste liquid of Comparative Example 1 (>8 mol / L) will accelerate the corrosion of the conveying pipeline and the tail gas pipeline due to its strong acidity, and shorten the service life of the equipment. When melting at high temperature, the nitrogen oxides produced by the decomposition of excessive nitrate will be released in a concentrated manner within a narrow temperature range, which will cause the melt volume to expand rapidly (such as a sudden increase in pressure in the "cold cap" area), and damage the stability of the process.

[0044] Figure 1 The image shows a SEM image of the Ru-containing simulated high-level radioactive waste glass solidified body prepared in Example 1. As can be seen from the image, when the nitric acid concentration in the simulated high-level radioactive waste liquid is 3 mol / L, the RuO2 precipitated in the glass solid mainly appears as short rods and particles.

[0045] Figure 2The image shows a SEM image of the Ru-containing simulated high-level radioactive waste glass solidified body prepared in Example 3. As can be seen from the image, when the nitric acid concentration in the simulated high-level radioactive waste liquid is 1 mol / L, the RuO2 precipitated in the glass solid is mainly in particulate form.

[0046] Figure 3 The image shows a SEM image of the Ru-containing simulated high-level radioactive waste glass solidified body prepared in Example 5. As can be seen from the image, when the simulated high-level radioactive waste undergoes an additional calcination step before being mixed with the base glass, more particulate RuO2 precipitates within the glass.

[0047] Figure 4 The image shows a SEM image of the Ru-containing simulated high-level radioactive waste glass solidified body prepared in Example 8. As can be seen from the image, when the nitric acid concentration in the simulated high-level radioactive waste liquid is 5 mol / L, the RuO2 precipitated in the glass solid mainly appears as long needles.

[0048] Figure 5 The image shows a SEM image of the Ru-containing simulated high-level radioactive waste glass solidified body prepared in Example 9. As can be seen from the image, when the nitric acid concentration in the simulated high-level radioactive waste liquid is 8 mol / L, the RuO2 precipitated in the glass solid mainly takes the form of long needles.

[0049] As can be seen from the SEM images, the technical solution of this invention effectively controls the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid. By adjusting the nitric acid concentration in the high-level radioactive waste liquid to 1-8 mol / L, the RuO2 precipitates are controlled to form granular, short rod-shaped, or long needle-shaped structures, thereby reducing the negative impact of ruthenium oxide precipitates on the properties of high-level radioactive glass melts.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for controlling the morphology of ruthenium oxide precipitates during the vitrification process of high-level radioactive waste liquid, characterized in that, Includes the following steps: S1. Mix the glass raw materials, heat and melt them, then cool and crush them to obtain basic glass particles with a particle size of 1–2 mm; S2. Dissolve the nitrate reagent in nitric acid to prepare a simulated high-level radioactive waste liquid with a nitric acid concentration of 1~8 mol / L. After evaporation, dry simulated high-level radioactive waste is obtained. S3. Mix the base glass with dry simulated high-level radioactive waste, heat and melt it, and then cool it to obtain a glass-cured sample. In step S2, when the nitric acid concentration is 1~3 mol / L, short rod-shaped and granular RuO2 crystals mainly precipitate in the solidified body; when the nitric acid concentration is 3~8 mol / L, long needle-shaped RuO2 crystals are formed.

2. The method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid as described in claim 1, characterized in that, The simulated high-level radioactive waste obtained after evaporation in step S2 is first calcined at 650~850 °C for 1.0~5.0 h, and then mixed with the base glass to obtain more granular RuO2 crystals or to transform needle-like RuO2 into granular form.

3. The method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid as described in claim 1, characterized in that, In step S3, the content of the base glass is 70-90 wt% and the content of the simulated high-level radioactive waste is 10-30 wt%, based on the mass percentage of oxides.

4. The method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid as described in claim 1, characterized in that, In step S1, the chemical composition of the glass raw material includes multiple components of SiO2, B2O3, Al2O3, CaO, Na2O, Li2O, and ZrO2.

5. The method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid as described in claim 4, characterized in that, Based on the mass percentage of oxides, the base glass contains 40 wt% to 60 wt% SiO2, 10 wt% to 20 wt% B2O3, 2 wt% to 10 wt% Al2O3, 1 wt% to 25 wt% CaO, 9 wt% to 26 wt% Na2O, 1 wt% to 5 wt% Li2O, and 1 wt% to 4 wt% ZrO2.

6. The method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid as described in claim 1, characterized in that, The simulated high-level radioactive waste liquid has a chemical composition including multiple substances from RuO2, Na2O, ZrO2, MoO3, Nd2O3, CeO2, La2O3, Pr2O3, Sm2O3, Y2O3, Gd2O3, Eu2O3, Cs2O, BaO, Fe2O3, SrO, Cr2O3, NiO, and SnO2.

7. The method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid as described in claim 6, characterized in that, Based on the mass percentage of oxides, the simulated high-level radioactive waste liquid contains RuO2 at 2 wt% to 10 wt%, Na2O at 8 wt% to 34 wt%, ZrO2 at 5 wt% to 20 wt%, MoO3 at 10 wt% to 20 wt%, and the total content of rare earth element oxides at 20 wt% to 45 wt%, with the contents of other components all greater than 0. Rare earth element oxides are one or more of Nd2O3, CeO2, La2O3, Pr2O3, Sm2O3, Y2O3, Gd2O3, and Eu2O3.

8. The method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid as described in claim 6, characterized in that, Based on the mass percentage of oxides, the simulated high-level radioactive waste glass solidified body contains 28 wt%~54 wt% SiO2, 7 wt%~18 wt% B2O3, 1.4 wt%~9 wt% Al2O3, 0.7 wt%~22.5 wt% CaO, 0.7 wt%~4.5 wt% Li2O, 8.7 wt%~28.4 wt% Na2O, 0.2 wt%~3 wt% RuO2, 1.4 wt%~8.8 wt% ZrO2, 1 wt%~4 wt% MoO3, and a total rare earth element oxide content of 2 wt%~13.5 wt%, with the contents of other components all greater than 0. Rare earth element oxides are one or more of Nd2O3, CeO2, La2O3, Pr2O3, Sm2O3, Y2O3, Gd2O3, and Eu2O3.

9. The method for controlling the morphology of ruthenium oxide precipitates during the glass curing process of high-level radioactive waste liquid as described in claim 1, characterized in that, In steps S1 and S3, the heating and melting temperature is 1100~1200 ℃; in step S2, the evaporation temperature is 150~200 ℃.

10. A vitrified body simulating high-level radioactive waste liquid, characterized in that: The glass-cured body is prepared by the method described in any one of claims 1 to 9.

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