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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]

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 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]

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.)

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.)