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In order to increase solubility of sulfur in borosilicate glass, SO42- ions in simulated high-level liquid waste (HLLW) with relatively high content of sulfur and sodium were pretreated by adding Ba(NO3)2 solution, and then borosilicate glass waste form was prepared by melt-quenching method. The effects of pretreated HLLW on the structure and leaching resistance were mainly investigated. The results show that the waste loading can be increased to 23% (mass fraction) without phase separation after the Ba(NO3)2 pretreatment. The normalized elemental mass loss of Na, B and Si of the HLLW-loaded samples are one order of magnitude lower than that of the pure borosilicate glass. Furthermore, the leaching resistance of the glass waste form has no significant change with increasing HLLW content. 11B and 29Si MAS NMR analyses indicate that part of BO3 transforms into BO4 structural units and a polymerization of the glass network occurs after HLLW addition. [ABSTRACT FROM AUTHOR]

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Waste glass powder and metakaolin were used to prepare geopolymer mortar. The effects of alkali activator with different sodium silicate modulus and liquid-solid ratios on the fluidity and mechanical properties of the waste glass powder-metakaolin geopolymer mortar were investigated, and the crystal structure, thermochemistry, pore structure, and micromorphology of the geopolymer mortar were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric-differential scanning thermal (TG-DSC), mercury in piezoelectricity (MIP), and scanning electron microscopy (SEM). The results show that the sodium silicate modulus and liquid-solid ratio have more obvious effects on the fluidity and mechanical properties of the geopolymer mortar. With the increase of sodium silicate modulus, the fluidity and strength of geopolymer mortar increase first and then decrease. When the sodium silicate modulus is 1.25, the alkali activator has the best excitation effect on the material, which increases the degree of reaction of the geopolymer, generates more hydration products, optimizes the pore structure of the matrix, and the compressive strength of 28 d reaches 43.0 MPa. The increase of liquid-solid ratio improves the fluidity of the geopolymer mortar, but decreases the compressive strength and has a negative effect on the pore structure. Moreover, the XRD, FTIR and TG-DSC results show that the waste glass in the geopolymer participates in the hydration reaction, provides Ca2+, and promotes the generation of C-S-H and C-A-S-H gels. [ABSTRACT FROM AUTHOR]

A large amount of low-level radioactive concrete nuclear waste with contamination and activation will be generated when the nuclear facilities are decommissioned. Glass material has been used to immobilize kinds of radioactive wastes because of its wide incorporation to radioactive elements and excellent chemical durability, compared with traditional cement solidification. In this paper, the simulated structural concrete nuclear waste was treated by high temperature melting. The concrete was vitrified with the glass additive (~26% (mass fraction) SiO2, ~13% (mass fraction) B2O3 and ~6% (mass fraction) Na2O) at 1 300 °C, and the chemical durability of thus resulted glass waste form meets the disposal requirements for low-level waste form. The volatilization behavior of the simulated nuclides at high temperature and their local structure in the glass were finally discussed. The results can provide the basic information to vitrify the concrete nuclear waste. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A new type of heat-resistant borosilicate glass was designed based on waste TFT-LCD glass raw materials. Aiming at the difficulty in clarification of the heat-resistant glass, which leads to a large amount of bubbles in the glass, the effects of four clarifying agents: CeO2, NaCl, Na2SO4 and SnO2 on the clarification quality of the heat-resistant glass were studied by high temperature video research method of glass batch. The experiment observed the clarification process of glass melt through a high-temperature video system. The results show that at the melting temperature of 1 600 °C, the best clarification effect is achieved when the addition amount of NaCl and Na2SO4 were added as a single clarifying agent at 0. 50% (mass fraction) and 0. 20% (mass fraction), respectively. The best clarification effect is achieved when the addition amount of clarifying agent combining CeO2 and SnO2 with NaNO3 is 0. 40% (mass fraction) CeO2 +2. 60% (mass fraction) NaNO3 and 0. 40% (mass fraction) SnO2 +2. 40% (mass fraction) NaNO3. The time for the glass melt foam to start falling back is 22, 10, 20 and 28 min, respectively. The initial falling temperatures are 1 110, 1 050, 1 103 and 1 143 °C, respectively. Under the optimum holding time, the clarification effect is best with 0. 50% (mass fraction) NaCl. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Waste glass powder, as a kind of solid waste with high content of SiO2, can effectively prevent the strength retrogression of oil well cement stone at high temperature, thereby improving the long-term sealing integrity of cement sheath in deep and ultra-deep wells. The effect of waste glass powder on compressive strength and microstructure of cement stone at 150 C, 21 MPa was studied in this paper. The results show that the 180 d compressive strength of neat cement stone is 8. 57 MPa, which is 76. 04% lower than 1 d compressive strength. The incorporation of waste glass powder improves the long-term stability of cement stone compressive strength. When 40% (mass fraction) cement is replaced by waste glass powder with a particle size of 45 μm, the 180 d compressive strength of cement stone is 31. 85 MPa, which is only 3. 95% lower than 1 d compressive strength. In addition, the 180 d permeability of cement stone is 1. 28 C 10 -2 mD, which is 16. 88% lower than 1 d permeability. The incorporation of waste glass powder changes the phase composition of cement stone. The neat cement stone is composed of portlandite and hillebrandite. The cement stone incorporating 40% waste glass powder with a particle size of 45 μm is made up of xonotlite and tobermorite. The grain size of xonotlite and tobermorite in cement stone is stable after incorporating 40% waste glass powder with a particle size of 45 μm. More large pores are produced in neat cement stone with the increase of curing age, while the structure in cement stone incorporating 40% waste glass powder with a particle size of 45 μm is denser, and gel pores are dominated within 180 d. [ABSTRACT FROM AUTHOR]

Incorporating waste glass powder (WGP) into concrete as supplementary cementitious materials (SCMs) offers a potential method for recycling glass. To facilitate the effective application, it is necessary to research the effect and mechanism of waste glass on mortar properties. In this paper, the effect of WGP with different particle sizes of 0 - 0. 075 mm, 0. 075 -0. 15 mm and 0. 15 -0. 3 mm as SCMs on the mechanical properties of mortar and expansion of alkali-silica reaction (ASR) was studied. The results show that the 28 d compressive strength of mortar increases by 5% - 15% and ASR expansion rate decreases by 20. 2% when the size of WGP is 0 -0. 075 mm. The 28 d compressive strength of mortar decreases by 5% -8% and the ASR expansion rate increases by 39. 7% when the size of WGP is 0. 15 - 0. 3 mm. To further explore the mechanism of performance change, thermogravimetric analysis, inductively coupled plasma and electron microscope and energy dispersive spectrometer were used to examine the resulting products, pore solution, microstructure and composition. The alkali aggregate activity of coarse WGP is strong, easy to ASR, resulting in ASR expansion rate increased. The pozzolanic reactivity of fine WGP is strong, the pozzolanic reaction produces calcium silicate hydrate gel with a low Ca/ Si ratio and a low expansion rate. The product absorbs Na+ and K+, reducing the number of reactants needed for ASR, and the resulting mortar is denser than the plain mortar, which is beneficial for reducing porosity, reducing water infiltration, and resisting expansion pressure. [ABSTRACT FROM AUTHOR]

Copyright of New Building Materials / Xinxing Jianzhu Cailiao is the property of New Building Materials Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Materials Science & Engineering (1673-2812) is the property of Journal of Materials Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Advanced Engineering Science / Gongcheng Kexue Yu Jishu is the property of Advanced Engineering Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The melting treatment and isotopic tracing experiments were carried out on a self-designed plasma bench melting test with glass solidification formulas of single waste as well as mixed waste of glass fiber, concrete and soil. After melting at 1 100-1 300 ℃ for 1 h, all the four samples were turned into glass waste-forms. The density, leaching and mechanical performance of resultant glass waste-forms were tested, showing the comparable requirement with the radioactive waste glasses. The results of the tracer experiment show that the plasma melting system has high interception rate for the tracer elements Co, Cs and Sr. In addition, the glass waste-forms has higher curing capacity for Co and Sr, but lower for Cs. In engineering application, it is suggested to add a pretreatment system such as granulation at the front of the melting furnace system to reduce the proportion of material directly entering the flue gas purification system and improve the solidified efficiency of the materials.

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to supress the formation of yellow phase during vitrification, simulated high-level liquid waste(HLLW) with high content of sulfur and sodium were pretreated by adding Ba(NO3)2 solution, and then borosilicate glass waste forms were prepared by traditional melting method. The effects of pretreatment on the formation of yellow phase and its phase structure and microstructure were mainly investigated. The sulfur content retained in the glass waste forms before and after pretreatment were compared. The results show that SO2-4 ions in the simulated HLLW can be immobilized in BaSO4. The amount of yellow phase during the vitrification process can be markedly reduced by the pretreatment. For the generated yellow phase before pretreatment, the main constituents are Na2SO4 and LiNaSO4 along with a small amount of CaMoO4 and Na2CrMoO4. After pretreatment, the X-ray diffraction peak intensity of LiNaSO4 decreases and BaSO4, BaMoO4, and BaCrO4 phases appear. The sulfur content retained in the glass waste form before pretreatment decreases gradually with increasing temperature. The sulfur content retained in the glass waste form after pretreatment remains almost unchanged in the temperature range of 850-1 050 ℃, and decreases gradually with further increasing temperature. The pretreatment is helpful to improve the sulfur retention especially for the higher sulfate-bearing HLLW.

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The molten salt reactor, utilizing molten fluoride salt as fuel solvent and coolant, is one of the generation-Ⅳ nuclear reactors for advanced nuclear energy. The generated fluoride nuclear waste during the operation of molten salt reactor and reprocessing of spent fuel should be immobilized in a stable matrix before disposal. At present, vitrification is still the only technology in the world that could industrially immobilize highlevel waste. However, such fluoride waste cannot be directly vitrified into borosilicate glass since it contains a large amount of F, which could lead to oversaturation in the glass. In order to provide an effective solution for the safe treatment of molten fluoride salt waste, H2C2O4 was used as a defluorination agent to defluorinate the simulated salt waste mainly consisting of alkali fluorides. The mixed sample of H2C2O4 and simulated fluoride salt waste was characterized with TG-DSC-MS and XRD to analyze the endothermic and exothermic behaviors, released gases, and phase transitions at elevated temperatures. Afterward, the effects of thermal treatment temperature and the molar ratio of H2C2O4 to F on the fluorine removal efficiency were investigated, and the optimal process parameters of defluorination were finally determined. The results show that H2C2O4 could react with alkali fluoride salt to release HF gas besides being decomposed into H2O, CO and CO2 at temperatures between 100 ℃ and 300 ℃, while the alkali fluorides turned to alkali oxalates, which could decompose to alkali carbonates at temperatures of 500 ℃. The fluorine removal efficiency would reach up to 93% when the molar ratio of H2C2O4 to F was 2 and the thermal treatment temperature was 300 ℃. The defluorinated waste thus obtained was then immobilized in a borosilicate glass waste form at about 1 200 °C with a waste loading of 25%, and the normalized elemental (B, Li, Na, K, Cs, Sr, and Ce) releases of the waste glass conducted with 7-day product consistency test were lower than 2.0 g/m2, showcasing acceptable durability for nuclear waste glass. The above results indicate that the proposed approach which defluorination with H2C2O4 in the first step at temperatures of below 300 °C and vitrifying the remaining waste into a borosilicate glass in the second step, would provide a practical way to safely treat the molten fluoride salt nuclear waste.

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of New Building Materials / Xinxing Jianzhu Cailiao is the property of New Building Materials Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of New Building Materials / Xinxing Jianzhu Cailiao is the property of New Building Materials Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)