CN106007366A - Radiation shielding glass and preparation method thereof - Google Patents
Radiation shielding glass and preparation method thereof Download PDFInfo
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- CN106007366A CN106007366A CN201610572109.1A CN201610572109A CN106007366A CN 106007366 A CN106007366 A CN 106007366A CN 201610572109 A CN201610572109 A CN 201610572109A CN 106007366 A CN106007366 A CN 106007366A
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- glass
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C3/00—Glass compositions
- C03C3/04—Glass compositions containing silica
- C03C3/062—Glass compositions containing silica with less than 40% silica by weight
- C03C3/07—Glass compositions containing silica with less than 40% silica by weight containing lead
- C03C3/072—Glass compositions containing silica with less than 40% silica by weight containing lead containing boron
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C3/00—Glass compositions
- C03C3/04—Glass compositions containing silica
- C03C3/062—Glass compositions containing silica with less than 40% silica by weight
- C03C3/07—Glass compositions containing silica with less than 40% silica by weight containing lead
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C4/00—Compositions for glass with special properties
- C03C4/08—Compositions for glass with special properties for glass selectively absorbing radiation of specified wave lengths
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Glass Compositions (AREA)
Abstract
The invention provides radiation shielding glass and a preparation method of the radiation shielding glass containing the same components. The radiation shielding glass is prepared from, by mass, SiO2 10-30%, PbO 25-60%, Al2O3 0-20%, B2O3 0-20%, Li2O 0-20%, Re2O3 (Re = Gd, Eu, Dy) 0-15%, In2O3 0-15% and CeO2 0-1.5%. The gamma ray absorption coefficients of the shielding glass are 0.5 cm-1 (0.511 MeV) and 0.3 cm-1 (1.25 MeV) or above, the visible light transmittance is higher than 80% when the thickness of the glass is 6 mm, the slow, medium, fast neutron shielding rates are respectively 97%, 40% and 20% or above, and the radiation shielding glass can be used for medical epithermal neutron radiation fields shielding gamma rays and neutron radiation in the nuclear industry or protection windows (plates) shielding gamma rays for PET checking.
Description
Technical field
The present invention relates to radiation shielding glass and preparation method thereof, particularly for gamma-rays and neutron irradiation shielding protection glass, this radiation shielding glass is gamma-rays and (or) neutron irradiation shielding protection window or shielding protection plate be applicable to nuclear industry and medical treatment.
Background technology
Nuclear material is the basis of nuclear technology, and along with the development of science and technology, the nuclear technology application in fields such as national defence, medical science and scientific researches is increasingly extensive.But no matter be in nuclear material preparation field or in Application of Nuclear Technology field, various radioprotective such as gamma-rays and neutron irradiation have the biggest radiation hazradial bundle to human body, instrument, environment etc., and cause the very big concern in International Radiation Protection field.Therefore various radiation are carried out the important leverage that good radiation shield is Application of Nuclear Technology and development.Shielding gamma-ray common used material at present is lead or lead bearing glass, and the common used material of shielding neutron irradiation is water, concrete and paraffin or the contour hydrogenous material of polyethylene.
In the development and production process of nuclear material, staff to carry out Real Time Observation to chemical reaction;In the medical treatment system using Epithermal Neutron Radiation Field or PET(positron emission tomography) check, operator want Real Time Observation and instruct those who are investigated.Operating room or inspection chamber etc. need to install radiation shield clear glass window to facilitate work in every to be smoothed out in this case.The window glass being applied to aforesaid operations room or inspection need to possess certain property: first, has good radiation shield performance, reduces the irradiation dose suffered by operator to greatest extent;Secondly, there is higher intensity and thermostability, it is ensured that window glass is safe and reliable;Finally, possess good transparent effect, facilitate operator to indoor Real Time Observation.Nuclear industry clear glass window mostly is lead bearing glass at present, and it is preferable but poor to the protective capacities of neutron to gamma-ray protective capacities.The high radiation shielding glass (seeing: Chinese Patent Application No. 200680038112. X) of a kind of PbO content that Nippon Electric Glass Co., Ltd announces, this shield glass maskable energy is the gamma-rays of 0.511MeV, but the protection to neutron has no report.Another kind of radiation shielding transparent material is the lucite of the doping such as boron or rare earth, as boron-doping polyethylene passes through10(n, α) reactive absorption thermal neutron of B, but be vulnerable to irradiation damage, and when neutron flux is big, shield produces helium generate heat (seeing: what builds flood etc., material Leader, 2011,25:347) because absorbing alpha ray;Although lead-boron polythene, boracic polypropylene have good engineering property, dimensional stability and gamma ray resistant irradiation behaviour, but it uses temperature to be only 80 ~ 100 DEG C (seeing: Ma Tao etc., macromolecule is circulated a notice of, 2011,9:81);Owing to some rare earth element exceeds tens times to the absorption cross-section of thermal neutron than elements such as B and Cd, rear-earth-doped polymer composite is the most ideal neutron irradiation shielding material, but rare earth ion can affect its mechanical performance to the Degradation of high polymer (to be seen: Liu Li etc., China rare earth journal, 2001,19(3): 193).Some shielding material has been widely used for nuclear reactor shielding harness at present, and along with the development of science and technology, people more focus on the protection of radiation risk crowd, therefore have higher requirement factors for radiation shielding window.Above-mentioned different materials still has following deficiency: radiation screening effect is bad, heat resistance and bad mechanical property, and Radiation hardness is more weak.
Inorganic transparent glass is widely used in the every field such as building, medical treatment, scientific research owing to having good thermostability and mechanical performance, has been applied to gamma-ray protection field such as lead glass, containing B2O3Glass be used as absorb slow neutron glass.Owing to the range of choice of unorganic glass component is the biggest, and each component can consecutive variations within the specific limits, therefore by the integrated protection that can realize the radiation of gamma-rays, fast neutron, intermediate neutron and slow neutron that cooperates of difference in functionality oxide in glass, but not yet retrieve at present and can realize gamma-rays and the inorganic transparent glass of neutron (including energy fast, middle and slow neutron) radiation shield simultaneously.
Summary of the invention
It is an object of the invention to provide a kind of shield glass that can shield gamma-rays and neutron irradiation, and its preparation method is provided.
The technical solution adopted for the present invention to solve the technical problems is: a kind of radiation shielding glass, represents by mass percentage, and its chemical constituent is SiO2: 10 ~ 30%, PbO:25 ~ 60%, Al2O3: 0 ~ 20%, B2O3: 0 ~ 20%, Li2O:0 ~ 20%, Re2O3(Re=Gd, Eu, Dy): 0 ~ 15%, In2O3: 0 ~ 15%, CeO2: 0 ~ 1.5%.
SiO2Being the composition forming glass network structure, can improve thermal stability, PbO is the main component of shielding gamma Rays, Al2O3It is the composition of degraded neutron, and is the composition improving thermal stability, B2O3It is the composition absorbing slow neutron, can speed up the clarification of glass simultaneously, reduce the crystallize ability of glass, Li2O is the composition absorbing slow neutron, is strong flux, Re2O3(Re=Gd, Eu, Dy) is degraded neutron and the composition absorbing slow neutron, In2O3It is degraded neutron and the composition of capture fast neutron, CeO2It it is the composition improving glass radiation-resistant property.
A kind of radiation shielding glass, its preparation method, comprise the following steps:
(1) glass melting: weigh raw material by joining certainty ratio, feeds after temperature rises to 950 ~ 1100 DEG C several times, then temperature rises to 1100 ~ 1300 DEG C and carries out melting sources.Frit is in fusion process, and timing agitation makes melt homogenization, and clarifying temp is higher than material temperature about 100 DEG C.
(2) glass castable technique: after completing glass material, homogenizing and clarification, between vitreous humour cooling down to 950 ~ 1200 DEG C, mold temperature controls between 460 ~ 650 DEG C, directly by glass melt castable.
(3) glass annealing process: the glass of castable is annealed at a temperature of 410 ~ 620 DEG C, to eliminate glass internal stress, meet the later stage cut, grind, the cold worked requirement such as polishing, finally give the shield glass finished product that can shield gamma-rays and neutron irradiation.
Owing to technique scheme is used, the present invention compared with prior art has the advantage that
(1) radiation shielding glass of the present invention has good screening ability to gamma-rays and neutron irradiation: containing considerable amount of PbO in this radiation shielding glass, therefore have good screening ability to gamma-rays;Containing multiple moderation of neutrons component in this radiation shielding glass, such as Al2O3、Re2O3(Re=Gd, Eu, Dy) or In2O3, medium nucleus element oxide is the strongest to the capture ability of fast neutron simultaneously, absorbs composition containing multiple slow neutron on this basis, such as B in radiation shielding glass2O3、Li2O or Re2O3(Re=Gd、Eu、Dy);Therefore this radiation shielding glass has good screening ability to neutron.Experiments verify that, only 6mm thickness radiation shielding glass pair252Cf fast neutron shielding rate more than 20%, intermediate neutron shielding rate more than 40%, the shielding rate of thermal neutron more than 97%, radiation shielding glass to the gamma ray absorption coefficient that energy is 0.511MeV at 0.50cm-1Above, to the gamma ray absorption coefficient that average energy is 1.25MeV at 0.28cm-1Above.
(2) the radiation shielding glass heat resisting temperature that the present invention is discussed is high, and satisfactory mechanical property, and its softening point is more than 460 DEG C, and Knoop hardness, more than 400, is superior to organic screen glass.
Detailed description of the invention
Below in conjunction with lower and the present invention is described in further detail in conjunction with specific embodiments.
Case study on implementation 1
A kind of radiation shielding glass, its chemical constituent content is: SiO2: 10%, PbO:35%, Al2O3: 20%, B2O3: 10%, Li2O:5%, In2O3: 10%, Gd2O3: 10%, CeO2: 0.5%.
In above compound, each amounts of components unit is by percentage to the quality.
The preparation method of radiation shielding glass described above is as follows, and its processing step is: (1) weighs raw material by joining certainty ratio, feeds several times, then temperature rises to 1100 ~ 1250 DEG C and carry out melting sources after temperature rises to 950 ~ 1100 DEG C.Frit is in fusion process, and timing agitation makes melt homogenization, and clarifying temp is higher than material temperature about 100 DEG C;(2) after completing glass material, homogenizing and clarification, between vitreous humour cooling down to 950 ~ 1100 DEG C, mold temperature controls between 460 ~ 550 DEG C, directly by glass melt castable;(3) glass of castable is annealed at a temperature of 410 ~ 500 DEG C, to eliminate glass internal stress.
Case study on implementation 2
A kind of radiation shielding glass, its chemical constituent content is: SiO2: 20%, PbO:45%, Al2O3: 15%, In2O3: 10%, Dy2O3: 10%, CeO2: 0.2%.
In above compound, each amounts of components unit is by percentage to the quality.
The preparation method of radiation shielding glass described above is as follows: (1) weighs raw material by joining certainty ratio, feeds several times, then temperature rises to 1200 ~ 1300 DEG C and carry out melting sources after temperature rises to 950 ~ 1100 DEG C;Frit is in fusion process, and timing agitation makes melt homogenization, and clarifying temp is higher than material temperature about 100 DEG C;(2) after completing glass material, homogenizing and clarification, between vitreous humour cooling down to 950 DEG C ~ 1200 DEG C, mold temperature controls between 500 ~ 650 DEG C, directly by glass melt castable;(3) glass of castable is annealed at a temperature of 500 ~ 620 DEG C, to eliminate glass internal stress.
Claims (8)
1. a radiation shielding glass, it is characterised in that represent by mass percentage, glass chemistry component is: SiO2: 10 ~ 30%, PbO:25 ~ 60%, Al2O3: 0 ~ 20%, B2O3: 0 ~ 20%, Li2O:0 ~ 20%, Re2O3(Re=Gd, Eu, Dy): 0 ~ 15%, In2O3: 0 ~ 15%, CeO2: 0 ~ 1.5%.
2. a radiation shielding glass, it is characterised in that represent by mass percentage, glass chemistry component is: SiO2: 10 ~ 30%, PbO:25 ~ 60%, Al2O3: 0 ~ 20%, B2O3: 0 ~ 20%, Li2O:0 ~ 20%, Re2O3(Re=Gd, Eu, Dy): 0 ~ 15%, In2O3: 0 ~ 15%, CeO2: 0 ~ 1.5%, can be used for nuclear industry gamma-rays and the shield glass window (plate) of neutron irradiation, medical Epithermal Neutron Radiation Field or PET inspection gamma Rays.
3. the radiation shielding glass as in any of the one of claims 1 ~ 2, it is characterised in that described radiation shielding glass is shaped as tabular, the thickness of this plate body is at more than 6mm.
4. the radiation shielding glass as described in claim 1 ~ 3, it is characterised in that the shielding protection window shielded for gamma-rays and (or) neutron irradiation or shielding protection plate.
5. the radiation shielding glass as described in claim 1 ~ 4, it is characterised in that for shielding protection window or the shielding protection plate of nuclear industry gamma-rays and neutron irradiation.
6. the radiation shielding glass as described in claim 1 ~ 4, it is characterised in that check with gamma-ray shielding protection window or shielding protection plate for medical Epithermal Neutron Radiation Field or medical PET.
7. a radiation shielding glass finished product, it is characterised in that possess the radiation shielding glass in any of the one of claim 1 ~ 6, and the plate glass being made up of single radiation shielding glass.
8. the preparation method of the radiation shielding glass as in any of the one of claim 1 ~ 7, its processing step is as follows: (1) glass melting: weigh raw material by joining certainty ratio, feed several times after high temperature furnace temperature is risen to 950 ~ 1100 DEG C, between 1100 ~ 1300 DEG C, carry out material;Frit is in fusion process, and timing agitation makes melt homogenization, and clarifying temp is higher than material temperature about 100 DEG C;(2) glass castable technique: after completing frit fusing, homogenizing and clarification, between vitreous humour cooling down to 950 ~ 1200 DEG C, mold temperature controls between 460 ~ 650 DEG C, directly by glass melt castable;(3) glass annealing process: annealed at a temperature of 410 ~ 620 DEG C by the glass of castable, meets later stage cold worked requirement eliminating glass internal stress.
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Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106587596A (en) * | 2016-10-31 | 2017-04-26 | 中国科学院西安光学精密机械研究所 | Heavy flint ZF series space radiation-resistant optical glass and preparation method thereof |
RU2661959C1 (en) * | 2017-04-07 | 2018-07-23 | федеральное государственное автономное образовательное учреждение высшего образования "Санкт-Петербургский национальный исследовательский университет информационных технологий, механики и оптики" (Университет ИТМО) | Glass |
CN111205107A (en) * | 2020-01-15 | 2020-05-29 | 武汉科技大学 | Radiation shielding composite material and preparation method thereof |
CN112250303A (en) * | 2020-10-28 | 2021-01-22 | 中国建筑材料科学研究总院有限公司 | High-strength radiation-proof glass and preparation method and application thereof |
CN112455027A (en) * | 2020-11-27 | 2021-03-09 | 中国建筑材料科学研究总院有限公司 | Laminated glass plate and manufacturing method thereof |
CN113979634A (en) * | 2021-12-02 | 2022-01-28 | 北方工业大学 | Novel X-ray radiation-proof special glass and preparation method thereof |
CN117585899A (en) * | 2023-12-06 | 2024-02-23 | 中建材光子科技有限公司 | Irradiation-resistant glass with gamma ray shielding and neutron protection functions and preparation method thereof |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101287685A (en) * | 2005-10-19 | 2008-10-15 | 日本电气硝子株式会社 | Radiation shielding glass and method for manufacture thereof |
JP2011251903A (en) * | 2000-06-05 | 2011-12-15 | Ohara Inc | Optical glass suffering little change in refractive index by radiation of light |
CN103597374A (en) * | 2011-03-29 | 2014-02-19 | 佐治亚技术研究公司 | Transparent glass scintillators, methods of making same and devices using same |
-
2016
- 2016-07-20 CN CN201610572109.1A patent/CN106007366A/en active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2011251903A (en) * | 2000-06-05 | 2011-12-15 | Ohara Inc | Optical glass suffering little change in refractive index by radiation of light |
CN101287685A (en) * | 2005-10-19 | 2008-10-15 | 日本电气硝子株式会社 | Radiation shielding glass and method for manufacture thereof |
CN103597374A (en) * | 2011-03-29 | 2014-02-19 | 佐治亚技术研究公司 | Transparent glass scintillators, methods of making same and devices using same |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106587596A (en) * | 2016-10-31 | 2017-04-26 | 中国科学院西安光学精密机械研究所 | Heavy flint ZF series space radiation-resistant optical glass and preparation method thereof |
CN106587596B (en) * | 2016-10-31 | 2019-08-27 | 中国科学院西安光学精密机械研究所 | Heavy flint ZF series space radiation-resistant optical glass and preparation method thereof |
RU2661959C1 (en) * | 2017-04-07 | 2018-07-23 | федеральное государственное автономное образовательное учреждение высшего образования "Санкт-Петербургский национальный исследовательский университет информационных технологий, механики и оптики" (Университет ИТМО) | Glass |
CN111205107A (en) * | 2020-01-15 | 2020-05-29 | 武汉科技大学 | Radiation shielding composite material and preparation method thereof |
CN112250303A (en) * | 2020-10-28 | 2021-01-22 | 中国建筑材料科学研究总院有限公司 | High-strength radiation-proof glass and preparation method and application thereof |
CN112455027A (en) * | 2020-11-27 | 2021-03-09 | 中国建筑材料科学研究总院有限公司 | Laminated glass plate and manufacturing method thereof |
CN112455027B (en) * | 2020-11-27 | 2022-09-20 | 中国建筑材料科学研究总院有限公司 | Laminated glass plate and manufacturing method thereof |
CN113979634A (en) * | 2021-12-02 | 2022-01-28 | 北方工业大学 | Novel X-ray radiation-proof special glass and preparation method thereof |
CN117585899A (en) * | 2023-12-06 | 2024-02-23 | 中建材光子科技有限公司 | Irradiation-resistant glass with gamma ray shielding and neutron protection functions and preparation method thereof |
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