Prediction method for leaching resistance of high-level borosilicate glass and application

Abstract

The invention provides a prediction method for leaching resistance of high-level borosilicate glass and application. Comprising the following steps: S1, obtaining an oxide component of high-level borosilicate glass; s2, predicting the mass loss per unit surface area of the high-level borosilicate glass in a static leaching test according to a formula # imgabs0 #; in the formula, L is the mass loss per unit surface area of the high-radioactivity borosilicate glass, # imgabs1 # i is the influence coefficient of the ith oxide component in the high-radioactivity borosilicate glass on the anti-leaching performance, # imgabs2 # ij is the influence coefficient of interaction between the ith oxide component and the jth oxide component in the high-radioactivity borosilicate glass on the anti-leaching performance, and the formula is shown in the description. And the # imgabs3 # i and the # imgabs4 # j are the mass fractions of the ith oxide component and the jth oxide component in the high-level borosilicate glass. According to the method, the mass loss per unit surface area of the high-level borosilicate glass under the static leaching test condition can be quickly and accurately predicted, the composition ratio optimization efficiency of the high-level borosilicate glass can be greatly improved, the research period is shortened, and the cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of solidification treatment of high-level radioactive nuclear waste, and particularly relates to a method for predicting the leaching resistance of high-level borosilicate glass and its application. Background Art

[0002] Glass solidification is a technology that calcines and melts high-level liquid waste with a glass substrate at high temperature to form a stable glass solid. This technology is a widely accepted and extensively developed method for treating high-level liquid waste worldwide. By fixing radionuclides in the "flexible" glass network structure, atomic-scale solidification of various toxic elements is achieved, preventing their migration to the external environment. Due to excellent chemical stability, relatively low melting temperature, etc., borosilicate glass has become the preferred substrate for glass solidification technology. After high-level liquid waste is solidified by borosilicate glass, it is usually disposed of in deep geological repositories, isolating it from the biosphere for tens to millions of years or more. However, groundwater will inevitably invade the isolation facilities, slowly corrode the engineering barriers, and finally contact the high-level borosilicate glass solid. After the high-level borosilicate glass solid contacts groundwater, it will start to dissolve and release radionuclides into the near-field environment, posing a great threat to the ecological environment. Therefore, the glass solid should have excellent chemical durability to slow down the migration of radionuclides as much as possible.

[0003] Therefore, the chemical durability of the solid is a key performance index that is highly concerned during the development stage of laboratory glass formulations. Currently, internationally, various methods such as dynamic leaching tests (ASTM C1662) and static leaching tests (ASTM C1285-02, ASTM C1220-2017) are often used to quickly evaluate the chemical durability of glass solids. The nuclear industry in China (EJ 1186-2005) mainly refers to the static leaching test standard as the evaluation method for the chemical durability of high-level borosilicate glass solids. This method uses deionized water as the leaching solution, keeping the ratio of the surface area of the glass solid sample to the volume of the immersion solution at 10.0 m -1 ±0.5 m -1 , and statically soaking for 28 days in a temperature environment of 90°C ± 1°C, and evaluating the chemical durability of the glass solid based on the mass loss per unit surface area of the sample. Currently, there is a lack of a prediction method suitable for quickly and accurately evaluating the leaching resistance of high-level borosilicate glass solids in China.

[0004] One of the purposes of optimizing the composition of high-level radioactive waste (HLW) glass is to improve the leaching resistance of the glass solid. Due to the lack of a prediction method applicable to quickly and accurately evaluate the leaching resistance of HLW borosilicate glass in China, currently, it is mostly based on literature and experience to qualitatively increase chemical components such as silica and alumina to enhance the durability of the glass. Then, glass solid samples are prepared by high-temperature melting, and the leaching resistance test lasting for more than one month is carried out to determine the further optimization plan of the composition. There are problems such as long formula development cycle and high cost. Summary of the Invention

[0005] In view of this, the present invention provides a prediction method and application for the leaching resistance of HLW borosilicate glass. This prediction method can directly predict the mass loss per unit surface area of HLW borosilicate glass under static leaching test conditions according to the given glass composition, so that the glass composition can be adjusted according to this predicted value to obtain a specific component ratio with the expected leaching resistance, reducing the time and cost of "trial-and-error" formula development.

[0006] The technical solution of the present invention is realized as follows: In the first aspect, the present invention provides a prediction method for the leaching resistance of HLW borosilicate glass, including the following steps: S1. Obtain the oxide components of the HLW borosilicate glass; S2. According to the formula , predict the mass loss per unit surface area of the HLW borosilicate glass in the static leaching test; In the formula, L is the predicted value of the mass loss per unit surface area of the HLW borosilicate glass, i is the influence coefficient of the i th oxide component in the HLW borosilicate glass on the leaching resistance, ij is the influence coefficient of the interaction between the i th and j th oxide components in the HLW borosilicate glass on the leaching resistance, i and j are the mass fractions of the i th and j th oxide components in the HLW borosilicate glass.

[0007] The deviation between the predicted value and the measured value of the mass loss per unit surface area is <±20%.

[0008] Based on the inherent relationship between the composition and properties of high-level radioactive borosilicate glass, a prediction method for the leaching resistance performance of high-level radioactive borosilicate glass solidified bodies applicable to China is established. By quantitatively calculating the oxide components of the given high-level radioactive borosilicate glass, the leaching resistance performance of the high-level radioactive borosilicate glass formula can be predicted, which can greatly improve the optimization efficiency of the composition of high-level radioactive borosilicate glass, shorten the formula research cycle, and reduce the formula research cost.

[0009] On the basis of the above technical solution, further, the oxide components of the high-level radioactive borosilicate glass, by mass fraction, include 35 - 55% SiO2, 5 - 20% B2O3, 0 - 10% Al2O3, 0 - 10% CaO, 5 - 18% Na2O, and 12 - 25% of the remaining components.

[0010] On the basis of the above technical solution, further, the oxide components of the high-level radioactive borosilicate glass, by mass fraction, include 43.5 - 49.5% SiO2, 13 - 18% B2O3, 3 - 6% Al2O3, 5 - 8% CaO, 10.0 - 13% Na2O, and 17 - 21% of the remaining components.

[0011] On the basis of the above technical solution, further, the influence coefficient of SiO2 on the leaching resistance performance is -3.0, the influence coefficient of B2O3 on the leaching resistance performance is 8.5, the influence coefficient of Na2O on the leaching resistance performance is 32.0, the influence coefficient of Al2O3 on the leaching resistance performance is 4.0, the influence coefficient of CaO on the leaching resistance performance is 50.0, the influence coefficient of the remaining components on the leaching resistance performance is -10.0, the influence coefficient of the interaction between B2O3 and Al2O3 on the leaching resistance performance is -150.0, and the influence coefficient of the interaction between Na2O and CaO on the leaching resistance performance is -310.0.

[0012] By screening quadratic terms in the regression analysis to optimize the model, removing the quadratic terms with insignificant influence on the leaching resistance performance among all possible quadratic terms that may affect the leaching resistance performance, finally, 2 quadratic terms with the most significant influence on the leaching resistance performance are selected, and the goodness of fit of the model reaches the optimal. That is, the interaction between B2O3 and Al2O3, and the interaction between Na2O and CaO have the most significant influence on the leaching resistance performance.

[0013] For the given composition of high-level radioactive borosilicate glass, only need to multiply the mass fraction of each oxide component by the corresponding Li value and accumulate, and after natural logarithm transformation, the predicted value of the leaching resistance performance of the high-level radioactive borosilicate glass can be obtained.

[0014] In high-level radioactive borosilicate glass, the i of various oxide components and ij The values are shown in Table 1 below.

[0015] Table 1 The i and ij values

[0016] On the basis of the above technical solutions, further, the remaining components include multiple ones among Li2O, ZrO2, La2O3, Nd2O3, CeO2, Cs2O, Fe2O3, NiO, Cr2O3, MnO and SrO.

[0017] On the basis of the above technical solutions, further, the static leaching test is to statically leach the high-level radioactive borosilicate glass in deionized water at 89°C to 91°C, and keep the ratio of the surface area of the high-level radioactive borosilicate glass to the volume of deionized water at 9.5 m -1 ~10.5m -1 , and after 28 days, calculate the mass loss per unit surface area of the high-level radioactive borosilicate glass.

[0018] In a second aspect, the present invention provides an application of the above prediction method in the formulation design of high-level radioactive borosilicate glass.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention provides a simple and rapid method for predicting the leaching resistance performance of high-level radioactive borosilicate glass. By only inputting the main components of the high-level radioactive borosilicate glass formula, the leaching resistance performance of the glass of this formula can be quickly predicted.

[0020] (2) Through the prediction method provided by the present invention, the glass composition design direction can be determined, and the component ratio with better performance can be calculated, providing guidance for the development of high-level radioactive borosilicate glass formula. Compared with the traditional formula design method, a large amount of experimental time and trial-and-error costs can be saved. Specific Embodiments

[0021] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0022] Example 1 This embodiment provides a method for predicting the leaching resistance of high-level radioactive borosilicate glass. Given a high-level radioactive borosilicate glass, its oxide composition by mass fraction is as follows: 46.0% SiO2, 13.0% B2O3, 12.0% Na2O, 2.0% Li2O, 4.0% Al2O3, 5.0% CaO, 2.0% BaO, 2.5% ZrO2, 2.5% La2O3, 1.5% CeO2, 2.5% MoO3, 0.5% Cr2O3, 1.0% Fe2O3, 0.5% NiO, 0.2% Rb2O, 0.3% Y2O3, 0.5% TeO2, 2.0% Nd2O3, 0.5% MnO, 1.0% Cs2O, 0.5% SrO.

[0023] Through the above prediction method, the mass loss per unit surface area of the high-level radioactive borosilicate glass in the leaching test is 7.4 g / m 2 .

[0024] Prepare the batch materials of high-level radioactive borosilicate glass according to the above proportions, where SiO2, B2O3, Al2O3, ZrO2, La2O3, Nd2O3, CeO2, MoO3, Fe2O3, NiO, Cr2O3, TeO2 and MnO are introduced in the form of oxides, and the remaining components are introduced in the form of carbonates. Mix the batch materials evenly and melt them in a high-temperature furnace at 1150 °C for 2 h. Pour the glass melt into a preheated cylindrical graphite crucible, and then anneal it in a heat treatment furnace at 450 °C for 2 h. After annealing and cooling, obtain the high-level radioactive borosilicate glass sample.

[0025] Cut the high-level radioactive borosilicate glass sample into a cylindrical shape with a surface area of about 400 mm 2 and polish each surface to obtain the test sample for the leaching resistance experiment.

[0026] The test sample is statically leached in deionized water at 90 °C ± 1 °C, keeping the ratio of the surface area of the test sample to the volume of ionic water at 10.0 m -1 ± 0.5 m -1 . After completing the 28-day leaching experiment, the mass loss per unit surface area is measured to be 8.5 g / m 2 , with a deviation of about 15% from the predicted value.

[0027] Example 2 This embodiment provides a method for predicting the leaching resistance of high-level radioactive borosilicate glass. The specific operation is the same as that in Embodiment 1, except that: to improve the leaching resistance of high-level radioactive borosilicate glass, without changing the waste encapsulation rate, the following components are adjusted under the guidance of the predicted value of the mass loss per unit surface area in the leaching test. In terms of mass fraction of oxides, it is: 47.5% SiO2, 15.0% B2O3, 10.0% Na2O, 2.5% Li2O, 3.0% Al2O3, 5.0% CaO, 1.0% BaO, 2.5% ZrO2, 2.5% La2O3, 1.5% CeO2, 2.5% MoO3, 0.5% Cr2O3, 1.0% Fe2O3, 0.5% NiO, 0.2% Rb2O, 0.3% Y2O3, 0.5% TeO2, 2.0% Nd2O3, 0.5% MnO, 1.0% Cs2O, 0.5% SrO.

[0028] Through the above prediction method, the mass loss per unit surface area of this high-level radioactive borosilicate glass in the leaching test is 6.3 g / m 2 .

[0029] After the test sample completed the 28-day leaching experiment, the measured mass loss per unit surface area was 6.2 g / m 2 , with a deviation of about 2% from the predicted value, and the leaching resistance of the glass formula was improved.

[0030] Embodiment 3 This embodiment provides a method for predicting the leaching resistance of high-level radioactive borosilicate glass. The specific operation is the same as that in Embodiment 1, except that: to further improve the leaching resistance of high-level radioactive borosilicate glass, the following components are adjusted under the guidance of the predicted value of the mass loss per unit surface area in the leaching test. In terms of mass fraction of oxides, it is: 49.5% SiO2, 14.5% B2O3, 13.0% Na2O, 0.0% Li2O, 6.0% Al2O3, 0.0% CaO, 1.0% BaO, 2.5% ZrO2, 2.5% La2O3, 1.5% CeO2, 2.5% MoO3, 0.5% Cr2O3, 1.0% Fe2O3, 0.5% NiO, 0.2% Rb2O, 0.3% Y2O3, 0.5% TeO2, 2.0% Nd2O3, 0.5% MnO, 1.0% Cs2O, 0.5% SrO.

[0031] Through the above prediction method, the mass loss per unit surface area of the leaching test of this high-level radioactive borosilicate glass is 3.5 g / m 2 .

[0032] After the leaching experiment of the sample to be tested was completed for 28 days, the mass loss per unit surface area was measured to be 3.2 g / m 2 , with a deviation of about 9% from the predicted value, and the leaching resistance of the glass formulation was further improved.

[0033] Example 4 This example provides a method for predicting the leaching resistance of high-level radioactive boron-silicate glass. The specific operation is the same as that of Example 1, except that the following components are adjusted while keeping the contents of the other components unchanged. In terms of mass fraction of oxides: 43.5% SiO2, 18.0% B2O3, 11.5% Na2O, 0.0% Li2O, 5.0% Al2O3, 5.0% CaO, 1.0% BaO, 2.5% ZrO2, 2.5% La2O3, 1.5% CeO2, 2.5% MoO3, 0.5% Cr2O3, 1.0% Fe2O3, 0.5% NiO, 0.2% Rb2O, 0.3% Y2O3, 0.5% TeO2, 2.0% Nd2O3, 0.5% MnO, 1.0% Cs2O, 0.5% SrO.

[0034] Through the above prediction method, the mass loss per unit surface area of the leaching test of this high-level radioactive boron-silicate glass is 6.5 g / m 2 .

[0035] After the leaching experiment of the sample to be tested was completed for 28 days, the mass loss per unit surface area was measured to be 7.2 g / m 2 , with a deviation of about 11% from the predicted value.

[0036] Example 5 This example provides a method for predicting the leaching resistance of high-level radioactive boron-silicate glass. The specific operation is the same as that of Example 1, except that a high-level radioactive boron-silicate glass is given, including the following oxide composition in mass fraction: 35.0% SiO2, 20.0% B2O3, 5.0% Na2O, 0.0% Li2O, 10.0% Al2O3, 10.0% CaO, 1.2% BaO, 2.9% ZrO2, 2.9% La2O3, 1.8% CeO2, 2.9% MoO3, 0.6% Cr2O3, 1.2% Fe2O3, 0.6% NiO, 0.2% Rb2O, 0.4% Y2O3, 0.6% TeO2, 2.4% Nd2O3, 0.6% MnO, 1.2% Cs2O, 0.5% SrO.

[0037] Through the above prediction method, the mass loss per unit surface area of the leaching test of this high-level radioactive boron-silicate glass is 3.9 g / m 2 .

[0038] After the 28-day leaching experiment of the sample to be tested, the mass loss per unit surface area was measured to be 3.2 g / m 2 , with a deviation of about 18% from the predicted value.

[0039] Example 6 This example provides a method for predicting the leaching resistance of high-level radioactive borosilicate glass. The specific operation is the same as that in Example 1, except that: a given high-level radioactive borosilicate glass includes the following oxide compositions by mass percentage: 55.0% SiO2, 5.0% B2O3, 18.0% Na2O, 5.0% Li2O, 0.0% Al2O3, 0.0% CaO, 1.0% BaO, 2.5% ZrO2, 2.5% La2O3, 1.5% CeO2, 2.5% MoO3, 0.5% Cr2O3, 1.0% Fe2O3, 0.5% NiO, 0.2% Rb2O, 0.3% Y2O3, 0.5% TeO2, 2.0% Nd2O3, 0.5% MnO, 1.0% Cs2O, 0.5% SrO.

[0040] Through the above prediction method, the mass loss per unit surface area of the leaching test of this high-level radioactive borosilicate glass is 20.3 g / m 2 .

[0041] After the 28-day leaching experiment of the sample to be tested, the mass loss per unit surface area was measured to be 23.7 g / m 2 , with a deviation of about 17% from the predicted value.

[0042] Comparative Example 1 This example provides a method for predicting the leaching resistance of high-level radioactive borosilicate glass. The specific operation is the same as that in Example 1, except that: a given high-level radioactive borosilicate glass includes the following oxide compositions by mass percentage: 36.0% SiO2, 11.0% B2O3, 3.0% Na2O, 6.0% Li2O, 20.0% Al2O3, 3.0% CaO, 1.3% BaO, 3.1% ZrO2, 3.1% La2O3, 1.8% CeO2, 3.1% MoO3, 0.6% Cr2O3, 1.2% Fe2O3, 0.6% NiO, 0.3% Rb2O, 0.4% Y2O3, 0.6% TeO2, 2.5% Nd2O3, 0.6% MnO, 1.2% Cs2O, 0.6% SrO.

[0043] The contents of Na2O and Al2O3 in the waste glass composition are not within the applicable range of this prediction method. Through the above prediction method, the mass loss per unit surface area of the leaching test of this high-level radioactive borosilicate glass is 0.1 g / m2 。

[0044] After the 28-day leaching experiment of the sample to be tested, the mass loss per unit surface area was measured to be 13.7 g / m 2 , which is quite different from the predicted value, and the deviation between the predicted value and the measured value is greater than 99%.

[0045] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A prediction method for the leaching resistance of high-level radioactive borosilicate glass, characterized in that, It includes the following steps: S1. Obtain the oxide components of the high-level radioactive borosilicate glass; S2. According to the formula , predict the mass loss per unit surface area of the high-level radioactive borosilicate glass in the static leaching test; In the formula, L is the mass loss per unit surface area of the high-level radioactive borosilicate glass, i is the influence coefficient of the i th oxide component in the high-level radioactive borosilicate glass on the anti-leaching performance, ij is the influence coefficient of the interaction between the i and j th oxide components in the high-level radioactive borosilicate glass on the anti-leaching performance, i and j are the mass fractions of the i th and j th oxide components in the high-level radioactive borosilicate glass.

2. The prediction method for the leaching resistance of high-level radioactive borosilicate glass according to claim 1, characterized in that, The oxide components of the high-level radioactive borosilicate glass, by mass fraction, include 35-55% SiO2, 5-20% B2O3, 0-10% Al2O3, 0-10% CaO, 5-18% Na2O, and 12-25% of the remaining components.

3. The prediction method for the leaching resistance of high-level radioactive borosilicate glass according to claim 1, characterized in that, The oxide components of the high-level radioactive borosilicate glass, by mass fraction, include 43.5-49.5% SiO2, 13-18% B2O3, 3-6% Al2O3, 5-8% CaO, 10.0-13% Na2O, and 17-21% of the remaining components.

4. The prediction method for the leaching resistance of high-level radioactive borosilicate glass according to claim 2 or 3, characterized in that, The influence coefficient of SiO2 on the leaching resistance performance is -3.0, the influence coefficient of B2O3 on the leaching resistance performance is 8.5, the influence coefficient of Na2O on the leaching resistance performance is 32.0, the influence coefficient of Al2O3 on the leaching resistance performance is 4.0, the influence coefficient of CaO on the leaching resistance performance is 50.0, the influence coefficient of the remaining components on the leaching resistance performance is -10.0, the influence coefficient of the interaction between B2O3 and Al2O3 on the leaching resistance performance is -150.0, and the influence coefficient of the interaction between Na2O and CaO on the leaching resistance performance is -310.

0.

5. The prediction method for the leaching resistance of high-level radioactive borosilicate glass according to claim 1, characterized in that, The remaining components include multiple ones among Li2O, ZrO2, La2O3, Nd2O3, CeO2, Cs2O, Fe2O3, NiO, Cr2O3, MnO, and SrO.

6. The prediction method for the leaching resistance of high-level radioactive borosilicate glass according to claim 1, characterized in that, The static leaching test is to statically leach the high-level borosilicate glass in deionized water at 89°C to 91°C, and keep the ratio of the surface area of the high-level borosilicate glass to the volume of deionized water at 9.5 m -1 ~10.5 m -1 . After 28 days, calculate the mass loss per unit surface area of the high-level borosilicate glass.

7. Application of the prediction method according to any one of claims 1 to 6 in the formulation design of high-level radioactive borosilicate glass.

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