CN-119038873-B - Borosilicate glass and preparation method and application thereof

Abstract

The invention discloses borosilicate glass and a preparation method and application thereof. The high-radioactivity waste liquid produced by the nuclear energy industry has huge environmental risks, and borosilicate glass is widely used as base glass for solidifying the high-radioactivity waste liquid internationally, so that the problem that molybdate yellow phase is easy to separate out in solidified glass is caused by low solubility of molybdenum in the borosilicate base glass in nuclear waste. The invention prepares the base glass with high molybdenum inclusion rate by adjusting the composition of borosilicate glass. Specifically, the method comprises the steps of gradually replacing B 2 O 3 with Al 2 O 3 to obtain the optimal composition which can be added with 8mol% of MoO 3 at most without crystallization, replacing Na 2 O and CaO with Li 2 O on the basis, keeping the molar ratio of Na 2 O to CaO unchanged in the process to obtain borosilicate glass which can be added with 11mol% of MoO 3 at most without crystallization, and improving the phenomenon of low inclusion rate of high-radioactivity nuclear waste in the glass solidification treatment process.

Inventors

• GUO LIWEN
• YANG DEBO
• SHAN ZHITAO
• CUI ZHU
• ZHU YONGCHANG
• LIU SHIQUAN

Assignees

• 齐鲁工业大学(山东省科学院)
• 中国建筑材料科学研究总院有限公司

Dates

Publication Date

20260512

Application Date

20240829

Claims (4)

1. 1. A borosilicate base glass for solidifying high-level nuclear waste is characterized in that the molar contents of oxides and oxides in the glass are SiO 2 60.28%、Al 2 O 3 7-10%、B 2 O 3 9.78-12.78%、Na 2 O 0-5.8%、CaO 0-5.7%、ZnO 2.45%、Li 2 O 5.29-16.79%、ZrO 2 0.7%, respectively, wherein the total amount of a composition B 2 O 3 and Al 2 O 3 in the glass is kept unchanged and 19.78%, when the content of Al 2 O 3 is increased, the content of B 2 O 3 is correspondingly reduced, the sum of a composition Li 2 O、Na 2 O, caO in the glass is 16.79%, the molar ratio of Na 2 O, caO in the composition is 1.02 and is kept unchanged, or the contents of the oxides and the Al 2 O 3 in the glass are 0%, and the content of Li 2 O in the base glass is 16.79% at the highest.
2. 2. A method for preparing the base glass as defined in claim 1, comprising the steps of: (1) According to the content of each oxide in glass composition, the raw materials required for preparing glass are respectively weighed, and the specific raw materials and the introduced oxides are respectively that silica sand is introduced into SiO 2 ;Na 2 B 4 O 7 ·10H 2 O to introduce Na 2 O and B 2 O 3 , if B 2 O 3 introduced into borax is insufficient, H 3 BO 3 is used for supplementing, if introduced Na 2 O is insufficient, na 2 CO 3 is used for supplementing, al (OH) 3 is introduced into Al 2 O 3 ;CaCO 3 to introduce CaO, znO is introduced into ZnO, li 2 CO 3 is introduced into Li 2 O;ZrO 2 to introduce ZrO 2; (2) Fully mixing the weighed raw materials until the raw materials are uniform, and putting the raw materials into a proper corundum crucible to be melted; (3) Placing the crucible with the batch into a melting furnace, heating to 1550 ℃ at a rate of 5 ℃ per minute, and melting at the temperature of 2h ℃; (4) After the melting was completed, the glass liquid was cast on a copper plate and allowed to cool freely to room temperature.
3. 3. A borosilicate cured glass containing MoO 3 , wherein 6 to 11mol% of MoO 3 is added to the composition of the base glass according to claim 1.
4. 4. A method for producing the cured body glass according to claim 3, comprising the steps of: (1) According to the content of each oxide in the glass composition, the raw materials required for preparing the glass are correspondingly weighed, wherein the specific raw materials and the introduced oxides are respectively silica sand introduced into SiO 2 ;Na 2 B 4 O 7 ·10H 2 O to introduce Na 2 O and B 2 O 3 , if B 2 O 3 introduced into borax is insufficient, H 3 BO 3 is used for supplementing, if introduced Na 2 O is insufficient, na 2 CO 3 is used for supplementing, al (OH) 3 is introduced into Al 2 O 3 ;CaCO 3 to introduce CaO, znO is introduced into ZnO, li 2 CO 3 is introduced into Li 2 O;ZrO 2 to introduce ZrO 2 ,MoO 3 to introduce MoO 3 ; (2) Fully mixing the weighed raw materials until the raw materials are uniform, and putting the raw materials into a proper corundum crucible to be melted; (3) Placing the crucible filled with the batch into a melting furnace, heating to 1550 ℃ at a rate of 5 ℃ per minute, and melting for 2 hours at the temperature; (4) After the melting was completed, the glass liquid was cast on a copper plate and allowed to cool freely to room temperature.

Description

Borosilicate glass and preparation method and application thereof Technical Field The invention belongs to the field of nuclear waste treatment, and mainly relates to borosilicate glass for curing high-radioactivity nuclear waste, and a preparation method and application thereof. Background Energy problems have been one of the focus of continued attention in countries. The fossil fuel can cause serious problems of atmospheric pollution, emission of greenhouse gases and the like in the using process. Nuclear energy is a supplement to fossil energy, but spent fuel treatment produces a large amount of highly radioactive waste liquid, which presents a significant safety hazard and can cause catastrophic damage to humans and the environment once an accident occurs. The most efficient method of disposing of such nuclear waste is currently to cure it followed by deep geological disposal. The use of glass as a matrix for solidifying highly radioactive nuclear waste is currently the method of practical successful application. Among them, borosilicate glass is widely used as a base glass for solidification of highly radioactive nuclear waste due to its good chemical stability, but it also has drawbacks. For example, the high-radioactivity nuclear waste liquid produced by the nuclear energy industry has a high molybdenum content, while its solubility in borosilicate glass is low, and the highest molybdenum solubility reported in the literature as MoO 3 (hereinafter the same applies) is not more than 5mol% (typically less than 2 mol%). Once the molybdenum content exceeds the solubility of the molybdenum in the glass, the formed solidified glass is extremely easy to generate phase separation and crystallization, particularly the precipitation of molybdate yellow phase (particularly soluble Na 2MoO4), thereby reducing the chemical stability of the solidified glass, causing the leaching rate of nuclear waste elements to be increased and having serious potential safety hazard. Therefore, borosilicate glass having low molybdenum solubility is difficult to use in solidification of high-level nuclear waste. Adjustment by the base glass composition is a possible way to increase the molybdenum solubility in borosilicate glass. Table 1 summarizes the results already available in the literature, and it is seen that the solubility of molybdenum in borosilicate glass is still low. Table 1 data of molybdenum solubility in borosilicate glass in literature Disclosure of Invention The invention aims to solve the problem that a yellow phase is precipitated in the solidified glass due to low molybdenum solubility in borosilicate glass, and further improves the molybdenum solubility in borosilicate glass through a composition innovative design. Specifically, the content of Al 2O3 was increased and the content of B 2O3 was decreased in the borosilicate glass composition, and based thereon, li 2 O was substituted [ Na 2 O+CaO ]. The result shows that through the composition design of the base glass, the highest MoO 3 with the concentration of 11mol percent can be added in the borosilicate glass developed by the invention, the prepared solidified body has no molybdate yellow phase precipitation, and the effect of improving the molybdenum solubility is obvious. To achieve the above objective, a set of borosilicate glass compositions was designed, with specific oxide content (mol%) ranges as shown in Table 2. It should be noted that the total amount of B 2O3 and Al 2O3 in the base glass composition was kept constant at 19.78%, and the content of B 2O3 was decreased when the content of Al 2O3 was increased, while the sum of Li 2O、Na2 O, caO in the base glass composition was 16.79%, and the molar ratio of Na 2 O, caO was kept constant at 1.02, or Na 2 O, caO was simultaneously 0, and the content of Li 2 O in the base was at most 16.79%. The preparation of borosilicate glass according to the composition given in table 2 requires the following steps: (1) According to the molar content of each oxide in the basic glass composition, the raw materials required for preparing the glass are correspondingly weighed. The specific raw materials and the introduced oxides are respectively that silica sand is introduced into SiO 2;Na2B4O7·10H2 O to introduce Na 2 O and B 2O3, if B 2O3 introduced into borax is insufficient, H 3BO3 is used for supplementing, if introduced Na 2 O is insufficient, na 2CO3 is used for supplementing, al (OH) 3 is introduced into Al 2O3;CaCO3 to introduce CaO, znO is introduced into ZnO, and Li 2CO3 is introduced into Li 2O;ZrO2 to introduce ZrO 2. (2) The weighed raw materials are thoroughly mixed until uniform, and are placed in a suitable corundum crucible to be melted. (3) The crucible with batch was placed in a melting furnace, warmed to 1550 ℃ at a rate of 5 ℃/min, and melted at this temperature for 2h. (4) After the melting was completed, the glass liquid was cast on a copper plate and allowed to cool freely to room temperatur