Method for suppressing needle-like precipitation of platinum group metal in vitrification process of high-level liquid waste

Abstract

To provide a method for suppressing the acicular deposition of a platinum group metal in a high level waste liquid glass solidification process.SOLUTION: Provided is a method for suppressing needle-like deposition of platinum group metals during vitrification of a high-level liquid waste, the method including S1 in which glass raw materials are mixed, heated and melted, and then crushed to obtain a particulate mother glass having a particle size of 0.050 to 0. 900mm, and S2 in which 70 to 90wt% of the mother glass and 10 to 30wt% of the high-level liquid waste are mixed, heated and melted, and then cooled and annealed to obtain a vitrified waste sample. By adjusting the particle size of the base glass and the mass ratio of Na2O / RuO2, the formation of needle-shaped precipitates of the platinum group metals is suppressed, and the platinum group metals are present in the glass matrix in the form of fine and uniformly dispersed particles, thereby reducing the influence of the precipitates of the platinum group metals on the conductivity and viscosity of the molten glass, and ensuring the safe operation of the nuclear waste vitrification melter.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the technical field of radioactive nuclear waste solidification treatment, and more particularly to a method for suppressing needle-like precipitation of platinum group metals during the vitrification process of high-level liquid waste. [Background technology]

[0002] The generation of high-level liquid waste is unavoidable during the post-processing of spent fuel. High-level liquid waste is highly biologically toxic and radioactive, posing a significant threat to the ecological environment. Therefore, it is typically vitrified and then geologically disposed of, isolating it from the biosphere to the greatest extent possible. Vitrification is a technique in which high-level liquid waste is evaporated and fired at high temperatures to fuse it with a glass substrate and then cast into a stable vitrified body. Vitrified bodies are leach-resistant, radiation-resistant, and compatible with a wide range of elements. Their production is easy to perform remotely, making them the only high-level liquid waste treatment technology currently available for engineering applications. However, the platinum group metals ruthenium (Ru), rhodium (Rh), and palladium (Pd) in high-level liquid waste have extremely low solubility in borosilicate glass (typically less than 100 ppm) and high melting points (>2000°C). Their chemical properties are stable, and they are often suspended as separate particles in the molten glass. The densities of platinum group metals and their oxides (7–13 g / cm) are low. 3 ) is the density of the glass melt (2.4 to 2.9 g / cm 3 ), and during long periods of continuous operation of the melting furnace, platinum group metal and oxide particles gradually grow and settle at the bottom of the molten pool, forming a "sludge"-like glass melt containing a large amount of platinum group metals. When the platinum group metal content of the "sludge" exceeds 15 wt%, its resistivity is more than 20 times lower than that of ordinary molten glass, which causes the local current density at the bottom of the melting furnace to be too high, making it prone to operation interruptions. Furthermore, its viscosity is generally nearly 10 times higher than that of the melt, making it prone to problems such as poor discharge and clogging of the discharge port.

[0003] Among platinum group metals, Ru is the most abundant in high-level waste (generally greater than 7 wt%), and its precipitates have the greatest impact on the performance of glass melts. Ru is mainly precipitated in the form of acicular RuO2 during the vitrification process. Previous research has shown that, for the same RuO2 precipitate content, the conductivity and viscosity of acicular RuO2 crystals are much higher than that of granular RuO2. The main reason for this is that acicular crystal particles are prone to forming a network structure, which increases the conductivity and viscosity and can lead to operating accidents in melting furnaces.

[0004] Regarding a method for controlling the morphology of platinum-group metal precipitates during the vitrification of high-level waste, prior patent 202211408096.6 disclosed a vitrified body and its manufacturing method for improving precious metal deposition. This involves adding small amounts of P2O5 and Fe2O3 to borosilicate glass to form particulate RuO2 precipitates, thereby improving the viscosity and electrical conductivity of the molten glass and extending the life of the vitrification furnace. However, the addition of P and Fe in this solution alters the chemical composition of the final vitrified body, posing challenges for practical use. For example, the addition of P increases the likelihood of phase separation in the borosilicate glass, reducing the chemical stability of the vitrified body. Meanwhile, the addition of Fe, together with elements such as Mg, Ni, and Cr in high-level waste, forms refractory spinel-phase precipitates during the vitrification process, leading to drain clogging and other challenges. Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above, the present invention provides a method for suppressing needle-like precipitation of platinum group metals in the vitrification process of high-level liquid waste, which solves the problem that the chemical stability of the vitrified body is reduced and more difficult-to-dissolve precipitates are formed in conventional methods for improving precious metal precipitation in the vitrification process of high-level liquid waste. [Means for solving the problem]

[0006] Aspects of the present invention are realized as follows.

[0007] In a first aspect, the present invention provides a method for producing a method of manufacturing a semiconductor device comprising: S1, in which glass raw materials are mixed, heated and melted, and then crushed and polished to obtain a granular base glass having a particle size of 0.050 to 0.900 mm; The present invention provides a method for suppressing needle-like precipitation of platinum group metals in a high-level liquid waste vitrification process, which includes step S2 of mixing a base glass with high-level liquid waste, heating and melting the mixture, and then cooling and annealing the mixture to obtain a vitrified sample.

[0008] Specifically, the present invention controls the morphology of platinum-group metal precipitates during the vitrification of high-level liquid waste by controlling the particle size and particle size distribution of the parent glass and the mass ratio of Na2O to RuO2 in the high-level vitrified waste without changing the chemical composition of the vitrified waste. When the particle size of the parent glass exceeds 1 mm, its surface area is small, its melting rate is slow, and the formation of a large, continuous glass liquid is delayed. This makes it easier for voids to form between the parent glass particles and the waste, leading to RuO2 precipitates growing along the voids and forming needle-like crystals. On the other hand, when the particle size of the parent glass is less than 1 mm, its surface area is large and it melts easily at high temperatures, reducing the voids between the parent glass particles and the waste. This limits the growth of RuO2 precipitates, resulting in the formation of particles rather than needle-like crystals.

[0009] More preferably, the particle size range of the mother glass is 0.075 to 0.800 mm, and even more preferably, the particle size range of the mother glass is 0.125 to 0.750 mm. In the most preferred embodiment, the particle size range of the mother glass is 0.125 to 0.750 mm, with the lower limit of 0.125 mm avoiding the problems of excessive reaction and volatilization loss caused by a particle size that is too small, and the upper limit of 0.750 mm avoiding the problem of voids affecting reaction uniformity caused by a particle size that is too large. In addition, within the range of 0.125 to 0.750 mm, a continuous glass phase is likely to form between the glass particles and the waste, and this continuous glass phase helps to limit the oriented growth of RuO2 crystals and suppress the formation of needle-like crystals.

[0010] In the above aspect, preferably, the deviation of the particle size distribution of the base glass is less than 0.250 mm.

[0011] The number or mass of particles in different particle size ranges is called the particle size distribution. Deviation is commonly used to describe the distribution of particle sizes. Deviation is used to measure the degree to which a particle size data set deviates from the average particle size. The smaller the deviation, the less the overall value deviates from the mean value. Preferably, the deviation of the particle size distribution of the matrix glass is less than 0.180 mm. Deviations greater than 0.250 mm result in poor uniformity and are prone to the precipitation of many RuO2 needles during high-temperature melting.

[0012] In the above aspect, the chemical composition (in terms of oxides) of the base glass preferably includes two or more of SiO2, B2O3, Al2O3, CaO, Li2O, and Na2O.

[0013] In the above aspect, preferably, the base glass has a SiO2 content of 40 wt% to 65 wt%, a B2O3 content of 13 wt% to 25 wt%, an Al2O3 content of 2 wt% to 10 wt%, a CaO content of 3 wt% to 15 wt%, a Li2O content of 0 wt% to 5 wt%, and a Na2O content of 6 wt% to 17 wt%, in mass percentages.

[0014] In the present invention, SiO2 is the main network former of glass, and its content determines the stability of the glass structure. B2O3, as a glass network former, can reduce the expansion coefficient of glass and improve the thermal and chemical stability of glass. Al2O3 can improve the acid resistance and temperature resistance of glass and improve the chemical stability of glass. CaO, as an alkaline earth metal oxide, can improve the water resistance and chemical resistance of glass. The two alkali metal oxides, Li2O and Na2O, are advantageous in improving the melting and processability of glass.

[0015] In the above aspect, preferably, the chemical composition (in terms of oxides) of the high-level liquid waste includes two or more of RuO2, Na2O, ZrO2, Nd2O3, MoO3, CeO2, Cs2O, BaO, Fe2O3, La2O3, Pr2O3, Sm2O3, SrO, Y2O3, Cr2O3, Rb2O, NiO, Gd2O3, Eu2O3, and SnO2.

[0016] In the above embodiment, preferably, in mass percentage, the content of RuO2 in the high-level waste is 2 wt% to 12 wt%, the content of Na2O is 15 wt% to 30 wt%, the content of ZrO2 is 5 wt% to 18 wt%, the content of rare earth element oxides is 6 wt% to 37 wt%, and the content of MoO3 is 6 wt% to 13 wt%, and the contents of all other components are greater than 0.

[0017] In the above aspect, the mass ratio of Na2O to RuO2 in the vitrified high-level liquid waste is preferably 8:1 to 20:1.

[0018] Specifically, Na2O, as a basic oxide, can disrupt the glass network structure and increase the melting point of glass. Na2O affects the viscosity and surface tension of the glass melt, further influencing the nucleation and growth kinetics of crystals. RuO2, as a platinum group metal oxide, is prone to precipitation and crystallization in high-level waste glass melts. When the Na2O / RuO2 ratio is in the range of 8-20 and the matrix glass particle size is in the range of 0.125-0.750 mm, the fine particle size of the matrix glass provides more heterogeneous nucleation sites. The appropriate Na2O content controls the melting properties and adjusts the diffusion rate of RuO2 in the glass melt to a moderate level. The synergistic effect of these two elements ensures that RuO2 is present in the glass matrix in the form of fine, uniformly dispersed particles.

[0019] In the above embodiment, preferably, in mass percentage, the SiO2 content in the vitrified high-level liquid waste is 38 wt% to 50 wt%, the B2O3 content is 8 wt% to 20 wt%, the Al2O3 content is 2 wt% to 6 wt%, the CaO content is 2 wt% to 10 wt%, the Li2O content is 0 wt% to 4 wt%, the Na2O content is 5 wt% to 20 wt%, the RuO2 content is 0.7 wt% to 2 wt%, the ZrO2 content is 1 wt% to 5 wt%, the rare earth element oxide content is 1 wt% to 7.5 wt%, and the MoO3 content is 1 wt% to 3 wt%, and the contents of the other components are all greater than 0.

[0020] In the above embodiment, the rare earth element oxide may preferably be one or more of Nd2O3, CeO2, La2O3, Pr2O3, Sm2O3, Y2O3, Gd2O3 and Eu2O.

[0021] In the above embodiment, preferably, in steps S1 and S2, the heat-melting temperature is 1100 to 1350°C, and in step S2, the annealing temperature is 300 to 550°C. More preferably, in steps S1 and S2, the heat-melting temperature is 1200 to 1300°C.

[0022] In a second aspect, the present invention provides a vitrified high-level liquid waste prepared using any one of the methods described above. [Effects of the Invention]

[0023] The method of the present invention for suppressing needle-like precipitation of platinum group metals in the vitrification process of high-level liquid waste has the following beneficial effects over the prior art.

[0024] (1) By adjusting the particle size of the base glass and the mass ratio of Na2O / RuO2, the formation of needle-like precipitates of platinum group metals is suppressed, and the platinum group metals are present in the glass matrix in the form of fine, uniformly dispersed particles. This reduces the effect of the precipitates on the conductivity and viscosity of the glass melt, ensuring the safe operation of the glass solidification melting furnace.

[0025] (2) The method of the present invention does not add any chemical reagents to the base glass or high-level liquid waste, does not change the chemical composition and performance of the high-level vitrified waste, and is widely applicable to high-level liquid waste with different chemical compositions. The operation process of the present invention is simple and easy to implement, and has good prospects for engineering application.

[0026] In order to more clearly describe the embodiments of the present invention or aspects of the prior art, the following briefly describes the drawings that need to be used in the description of the embodiments or prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without paying creative labor. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is an SEM image of the vitrified high-level liquid waste obtained in Example 1 of the present invention. [Figure 2] FIG. 2 is an SEM image of the vitrified high-level liquid waste obtained in Example 2 of the present invention. [Figure 3] FIG. 3 is an SEM image of the vitrified high-level liquid waste obtained in Comparative Example 3 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, the aspects of the embodiments of the present invention will be described clearly and completely with reference to the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, and are not all of them. Based on the embodiments of the present invention, all other embodiments that a person skilled in the art can obtain without paying creative labor fall within the scope of protection of the present invention.

[0029] Example 1

[0030] This example provides a method for suppressing needle-like precipitation of platinum group metals during the vitrification process of high-level liquid waste. A simulated vitrified high-level waste containing Ru was produced, the design composition of which is shown in Table 1, and the specific steps are as follows:

[0031] (1) Borosilicate glass raw materials are weighed and mixed uniformly, where SiO2, B2O3, Al2O3, and ZrO2 are introduced in the form of oxides, and CaO, Na2O, and Li2O are introduced in the form of carbonates.

[0032] (2) 60 g of the mixed raw materials were placed in a corundum crucible and heated and melted in a muffle furnace at 1200 °C for 1 hour. The glass liquid was then removed and allowed to cool naturally on a copper plate. It was then crushed to obtain a borosilicate base glass with a particle size of 0.325 ± 0.180 mm.

[0033] (3) The base glass particles were mixed with simulated high-level waste containing Ru in the calculated ratio, and 10 g of the mixture was placed in a corundum crucible and heated and melted in a muffle furnace at 1200°C for 1 hour. The sample was then removed and kept at 400°C in an annealing furnace for 2 hours, finally obtaining a simulated vitrified body sample containing Ru, where the mass ratio of Na2O to RuO2 was 9:1.

[0034] [Table 1]

[0035] Example 2

[0036] This example provides a method for suppressing needle-like precipitation of platinum group metals during the vitrification process of high-level liquid waste. A simulated vitrified high-level waste containing Ru was produced, the design composition of which is shown in Table 2. The specific steps are as follows:

[0037] (1) Borosilicate glass raw materials are weighed and mixed uniformly, where SiO2, B2O3, Al2O3, and ZrO2 are introduced in the form of oxides, and CaO, Na2O, and Li2O are introduced in the form of carbonates.

[0038] (2) 60 g of the mixed raw materials were placed in a corundum crucible and heated and melted in a muffle furnace at 1200 °C for 1 hour. The glass liquid was then removed and allowed to cool naturally on a copper plate. It was then crushed to obtain a borosilicate base glass with a particle size of 0.325 ± 0.180 mm.

[0039] (3) The base glass particles were mixed with simulated high-level waste containing Ru in the calculated ratio, and 10 g of the mixture was placed in a corundum crucible and heated and melted in a muffle furnace at 1200°C for 1 hour. The sample was then removed and kept at a temperature of 400°C for 2 hours in an annealing furnace. Finally, a simulated vitrified body sample containing Ru was obtained, with a mass ratio of Na2O to RuO2 of 19:1.

[0040] [Table 2]

[0041] Example 3

[0042] This example provides a method for suppressing needle-like precipitation of platinum group metals during the vitrification process of high-level liquid waste. A simulated vitrified high-level waste containing Ru was produced, the design composition of which is shown in Table 3. The specific steps are as follows:

[0043] (1) Borosilicate glass raw materials are weighed and mixed uniformly, where SiO2, B2O3, Al2O3, and ZrO2 are introduced in the form of oxides, and CaO, Na2O, and Li2O are introduced in the form of carbonates.

[0044] (2) 60 g of the mixed raw materials were placed in a corundum crucible and heated to 1300°C in a muffle furnace for 0.8 h. The glass liquid was then removed and allowed to cool naturally on a copper plate. It was then crushed and polished to obtain a borosilicate base glass with a particle size of 0.050±0.230 mm.

[0045] (3) The base glass particles were mixed with simulated high-level waste containing Ru in the calculated ratio, and 10 g of the mixture was placed in a corundum crucible and heated and melted in a muffle furnace at 1200°C for 0.8 hours. The sample was then removed and kept at a temperature of 300°C for 1.5 hours in an annealing furnace. Finally, a simulated vitrified sample containing Ru was obtained, where the mass ratio of Na2O to RuO2 was 13:1.

[0046] [Table 3]

[0047] Example 4

[0048] This example provides a method for suppressing needle-like precipitation of platinum group metals during the vitrification process of high-level liquid waste. A simulated vitrified high-level waste containing Ru was produced, the design composition of which is shown in Table 4. The specific steps are as follows:

[0049] (1) Weighing and uniformly mixing borosilicate glass raw materials, where SiO2, B2O3, Al2O3, and ZrO2 are introduced in the form of oxides, and CaO, Na2O, and Li2O are introduced in the form of carbonates;

[0050] (2) 60 g of the mixed raw materials were placed in a corundum crucible and heated and melted in a muffle furnace at 1250 °C for 1.2 h. The glass liquid was then removed and allowed to cool naturally on a copper plate. It was then crushed to obtain a borosilicate base glass with a particle size of 0.72 ± 0.180 mm.

[0051] (3) The base glass particles were mixed with simulated high-level waste containing Ru in the calculated ratio, and 10 g of the mixture was placed in a corundum crucible and heated and melted in a muffle furnace at 1200°C for 1.2 hours. The sample was then removed and kept at a temperature of 500°C in an annealing furnace for 2.5 hours. Finally, a simulated vitrified sample containing Ru was obtained, where the mass ratio of Na2O to RuO2 was 19:1.

[0052] [Table 4]

[0053] Comparative Example 1

[0054] This example provides a method for suppressing needle-like precipitation of platinum group metals during the vitrification process of high-level liquid waste. In step (1), the specific procedures are the same as in Example 2, except that borosilicate base glass with a particle size of 0.325±0.30 mm is obtained by crushing.

[0055] Comparative Example 2

[0056] This example provides a method for suppressing needle-like precipitation of platinum group metals during the vitrification of high-level liquid waste. The mass ratio of Na2O to RuO2 in the vitrified high-level liquid waste is 25:1, and a simulated vitrified high-level waste containing Ru is produced. The design composition is shown in Table 5. However, the specific operation is the same as in Example 2.

[0057] [Table 5]

[0058] Comparative Example 3

[0059] This comparative example provides a method for suppressing needle-like precipitation of platinum group metals during the vitrification process of high-level liquid waste. In step (1), the specific operating procedures are the same as in Example 1, except that borosilicate base glass with a particle size of 1.2±0.180 mm is obtained by crushing.

[0060] Performance Detection

[0061] The resistivity (1150°C) of the vitrified high-level liquid waste prepared in the examples and comparative examples was tested, and the measurement results are shown in Table 6.

[0062] [Table 6]

[0063] Figure 1 is an SEM image of the simulated vitrified high-level liquid waste containing Ru obtained in Example 1. As can be seen from the figure, when the particle size of the base glass is 0.325±0.180 mm, the RuO2 precipitated in the glass body is mainly in the form of particles.

[0064] Figure 2 is an SEM image of the simulated vitrified high-level liquid waste containing Ru obtained in Example 2. As can be seen from the figure, when the particle size of the base glass is 0.325±0.180 mm, the RuO2 precipitated in the glass body is mainly in the form of particles.

[0065] Figure 3 is an SEM image of the simulated vitrified high-level liquid waste containing Ru obtained in Comparative Example 3. As can be seen from the figure, when the particle size of the base glass is 1.2±0.180 mm, the RuO2 precipitated in the glass body is mainly needle-shaped.

[0066] As can be seen from Table 1, comparing Examples 1 to 4, according to the present invention, needle-like precipitation of platinum group metals in high-level vitrified waste can be effectively suppressed, and the impact of platinum group metal precipitates on the resistivity and viscosity of high-level glass melt can be reduced. Example 2, compared to Comparative Example 1, showed that when the particle size deviation was greater than 0.25 mm, uniformity was poor, and many RuO2 needle crystals were likely to precipitate during the high-temperature melting process, resulting in a nearly three-fold decrease in the resistivity of the glass melt. Example 2, compared to Comparative Example 2, showed that when the mass ratio of Na2O to RuO2 was 8 to 20:1, the synergistic effect with the particle size of the matrix glass could effectively suppress needle-like precipitation of platinum group metals. Example 1, compared to Comparative Example 3, showed that when the matrix glass particle size was greater than 1 mm, platinum group metals were likely to form and precipitate needle-like crystals, resulting in a nearly three-fold decrease in the resistivity of the glass melt.

[0067] The above 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 without departing from the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. S1: mixing glass raw materials, heating and melting them, and then crushing them to obtain a granular base glass having a particle size of 0.050 to 0.900 mm; A method for suppressing needle-like precipitation of platinum group metals in a high-level liquid waste vitrification process, comprising the steps of: mixing 70 to 90 wt % of base glass with 10 to 30 wt % of high-level liquid waste (converted to oxides); heating and melting the mixture; and then cooling and annealing the mixture to obtain a glass solidified sample.

2. 2. A method for suppressing needle-like precipitation of platinum group metals in a high-level liquid waste vitrification process according to claim 1, wherein the deviation of the particle size distribution of the base glass is less than 0.250 mm.

3. The chemical composition of the base glass is SiO 2 , B 2 O 3 , Al 2 O 3 , CaO, Li 2 O and Na 2 2. The method for suppressing needle-like precipitation of platinum group metals in a high-level liquid waste vitrification process according to claim 1, wherein the method comprises the steps of:

4. SiO in the base glass, in mass percentage 2 The content of is 40 wt% to 65 wt%, B 2 O 3 The content of is 13 wt% to 25 wt%, Al 2 O 3 The content of is 2 wt% to 10 wt%, the content of CaO is 3 wt% to 15 wt%, and Li 2 The O content is 0 wt% to 5 wt%, Na 2 4. The method for suppressing needle-like precipitation of platinum group metals in a high-level liquid waste vitrification process according to claim 3, wherein the O content is 6 wt % to 17 wt %.

5. The chemical composition of the high-level liquid waste is RuO 2 , Na 2 O, ZrO 2 , Nd 2 O 3 , MoO 3 , CeO 2 , Cs 2 O, BaO, Fe 2 O 3 , La 2 O 3 , Pr 2 O 3 , Sm 2 O 3 , SrO, Y 2 O 3 , Cr 2 O 3 , Rb 2 O, NiO, Gd 2 O 3 ,EU 2 O 3 and SnO 2 2. The method for suppressing needle-like precipitation of platinum group metals in a high-level liquid waste vitrification process according to claim 1, wherein the method comprises a plurality of the following:

6. In mass percentage, RuO in the high-level waste 2 The content of is 2wt% to 12wt%, Na 2 The O content is 15 wt% to 30 wt%, ZrO 2 The content of rare earth element oxide is 5 wt% to 18 wt%, the content of rare earth element oxide is 6 wt% to 37 wt%, and MoO 3 6. A method for suppressing needle-like precipitation of platinum group metals during the vitrification process of high-level liquid waste according to claim 5, characterized in that the content of is 6 wt% to 13 wt%, and the contents of all other components are greater than 0.

7. Na in the high-level liquid waste vitrified form 2 O and RuO 2 2. The method for suppressing needle-like precipitation of platinum group metals in a high-level liquid waste vitrification process according to claim 1, wherein the mass ratio of (a) to (b) is 8:1 to 20:

1.

8. SiO in vitrified high-level liquid waste by mass percentage 2 The content is 38 wt% to 50 wt%, B 2 O 3 The content is 8 wt% to 20 wt%, Al 2 O 3 The content is 2 wt% to 6 wt%, the CaO content is 2 wt% to 10 wt%, and the Li 2 O content is 0 wt% to 4 wt%, Na 2 O content is 5 wt% to 20 wt%, RuO 2 Content is 0.7wt% to 2wt%, ZrO 2 The content is 1 wt% to 5 wt%, the content of rare earth element oxide is 1 wt% to 7.5 wt%, MoO 3 8. A method for suppressing needle-like precipitation of platinum group metals during the vitrification process of high-level liquid waste according to claim 7, characterized in that the content of is 1 wt % to 3 wt %, and the contents of all other components are greater than 0.

9. z A method for suppressing needle-like precipitation of platinum group metals in the vitrification process of high-level liquid waste as described in claim 1, characterized in that in steps S1 and S2, the heating and melting temperature is 1100 to 1350°C, and in step S2, the annealing temperature is 300 to 550°C.

10. A vitrified form of high-level liquid waste, which is prepared by the method according to any one of claims 1 to 9.

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