Soda-lime Silicate Research Articles

Separation and determination of sulfide sulfur and sulfate sulfur in soda lime silicate glass

The quantities of sulfide sulfur and sulfate sulfur and the average valence of sulfur in soda lime silicate glass are important because they affect the number of bubble defects and color of the glass. In this paper, we describe and demonstrate a new determination method of sulfide and sulfate in glass. This method consists of decomposition of a glass material and the separation and determination of sulfide and sulfate. Hydrochloric acid and hydrofluoric acid decompose the material in a vessel. The vessel is combined with a series of traps. Hydrogen peroxide and sodium hydroxide in the traps absorb hydrogen sulfide that volatilizes during decomposition. This method allows for the determination of sulfate remaining in the vessel and the trapped sulfide, respectively. The method is tested on two glass reference materials with commonly accepted testing equipment. The sums of sulfide and sulfate are within the range of each certified value. The average valences of sulfur, which are calculated from the quantities of sulfide and sulfate, are in good agreement with the average valences of sulfur obtained by wavelength-dispersive X-ray fluorescence spectrometric analysis.

Structural origin of thermal shrinkage in soda-lime silicate glass below the glass transition temperature: A theoretical investigation by microsecond timescale molecular dynamics simulations.

Microscopic dynamical features in the relaxation of glass structures are one of the most important unsolved problems in condensed matter physics. Although the structural relaxation processes in the vicinity of glass transition temperature are phenomenologically expressed by the Kohlrausch-Williams-Watts function and the relaxation time can be successfully interpreted by Adam-Gibbs theory and/or Narayanaswamy's model, the atomic rearrangement, which is the origin of the volume change, and its driving force have not been elucidated. Using the microsecond time-scale molecular dynamics simulations, this study provides insights to quantitatively determine the origin of the thermal shrinkage below Tg in a soda-lime silicate glass. We found that during annealing below Tg, Na ions penetrate into the six-membered silicate rings, which remedies the acute O-O-O angles of the energetically unstable rings. The ring structure change makes the space to possess the cation inside the rings, but the ring volume is eventually reduced, which results in thermal shrinkage of the soda-lime silica glass. In conclusion, the dynamical structural relaxation due to the cation displacement evokes the overall volume relaxation at low temperature in the glassy material.

Ion-exchange diffusion kinetics and compressive stress analysis of float soda lime silicate glasses

Ion-exchange diffusion kinetics and compressive stress analysis of float soda lime silicate glasses

Characterization of mineral wool waste chemical composition, organic resin content and fiber dimensions: Aspects for valorization.

Despite mineral wool waste is only a small fraction of total construction and demolition waste (CDW) by mass, it requires large transportation and landfilling capacities due to its low bulk density, and its utilization remains low compared to other CDW types. It is essential to understand the physical and chemical properties of this waste fraction in order to utilize it, e.g. as fiber reinforcement in composites or as supplementary cementitious material. Here, we provide a chemical and physical characterization of 15 glass wool and 12 stone wool samples of different ages collected from various locations across Europe. In addition, the chemical compositions of 61 glass and stone wool samples obtained from the literature are presented. Glass wool samples show little variation in their chemical composition, which resembles the composition of typical soda-lime silicate glass. Stone wool presents a composition similar to basaltic glass but with variability between samples in terms of calcium, magnesium, and iron content. Potentially toxic elements, such as Cr, Ba, and Ni, are present in mineral wools, but in low concentrations (<0.2%). Both wool types contain organic resin, which may decompose into smaller molecular fragments and ammonia upon heating or contact with alkaline solution. Mineral wool wastes have relatively similar length and width distributions, despite the age and type of the mineral wool. Overall, both mineral wool waste types have homogenous chemical and physical properties as compared to many other mineral wastes which makes their utilization as a secondary raw material promising.

Coupling Raman, Brillouin and Nd3+ Photo Luminescence Spectroscopy to Distinguish the Effect of Uniaxial Stress from Cooling Rate on Soda-Lime Silicate Glass.

Evolution of spectroscopic properties of a soda–lime silicate glass with different thermal history and under applied uniaxial stress was investigated using Raman and Brillouin spectroscopies as well as Nd3+ photoluminescence techniques. Samples of soda–lime silicate with a cooling rate from 6 × 10−4 to 650 K/min were prepared either by controlled cooling from the melt using a differential scanning calorimeter or by a conventional annealing procedure. Uniaxial stress effects in a range from 0 to −1.3 GPa were investigated in situ by compression of the glass cylinders. The spectroscopic observations of rearrangements in the network structure were related to the set cooling rates or the applied uniaxial stress to calculate an interrelated set of calibrations. Comparing the results from Raman and Brillouin spectroscopy with Nd3+ photoluminescence analysis, we find a linear dependence that can be used to identify uniaxial stress and cooling rate in any given combination concurrently. The interrelated calibrations and linear dependence models are established and evaluated, and equations relating the change of glass network due to effects of cooling rate or uniaxial stress are given.

Coupling of diffusion and chemical stress: The case of ion exchange in glass

AbstractThe chemical strengthening of glass results from an ion exchange process in which smaller alkali ions in a glass are replaced with larger alkali ions from a molten salt bath. This interdiffusion process leads to a buildup of chemical stress in the glass. However, traditional modeling of the ion exchange process has not fully accounted for interaction effects between mass diffusion and the chemical stress developed during the process. In this study, we develop the general theory of coupling between diffusion and stress, resulting in a single flux equation with a concentration‐ and stress‐dependent interdiffusion coefficient. We apply the theory to the specific cases of chemically strengthened soda lime silicate and aluminosilicate glasses, demonstrating the impact of interaction terms on concentration profiles and interdiffusion coefficient. Following a phenomenological approach, this study demonstrates the effect of the interdiffusion on stress generation and vice versa to account for deviations from the simple expressions published hitherto in the literature.

Effects of acid leaching treatment of soda‐lime silicate glass on crack initiation and fracture

AbstractWater or acid soaking surface treatments have been shown to increase the mechanical strength of soda‐lime silicate (SLS) glasses. This increase in strength has traditionally been attributed to effects related to residual stress or changes in fracture resistance. In this work, we report experimental data that cannot be explained based on the existing knowledge of glass surface mechanics. In dry environments, annealed and acid‐leached SLS surfaces have comparable crack initiation stress and fracture stress as measured by Hertzian indentation and biaxial bending tests, respectively. Yet, in the presence of humidity, acid‐leached surfaces have higher failure stress than the annealed surfaces. This apparent enhancement in the crack resistance of the acid‐leached surface of SLS glass in humid environments supports the hypothesis that acid‐leached surface chemistry can lower the transport kinetics of molecular water to critical flaws.

Interfacial heterogeneous precipitation of Ag nanoparticles in soda-lime silicate glass for improved toughness and conductivity

The fracture toughness and thermal conductivity of soda-lime glass were enhanced by an interfacial precipitation of Ag. Large quantities of silver nanoparticles (AgNPs) are formed on the surface and subsurface layers of the Ag–Na ion exchanged glass powders during the heat-treatment in H2 for various times, and are fully densified by subsequent spark plasma sintering (SPS). The AgNPs with particle sizes above 50 nm are mainly located near the interfaces with the original glass particles, whereas smaller AgNPs are observed inside the glass particles. Moreover, the thickness of the precipitated Ag layer is seen to increase with increasing heat-treatment time. The incorporation of AgNPs is shown to enhance the fracture toughness of the soda-lime glass due to ductile deformation, crack deflection, and crack bridging. Finally, a maximum fracture toughness of 1.14 MPa m1/2, and a maximum thermal conductivity of 1.20 W m−1K−1, are obtained for the glass powders that were subjected to the entire process of ion-exchange, heat-treatment, and SPS densification.

Two- step ion- exchanged soda lime silicate glass: Effect of surface compression on silver ion release

Two- step ion- exchanged soda lime silicate glass: Effect of surface compression on silver ion release

Two‐step ion‐exchanged soda lime silicate glass: Effect of surface compression on silver ion release

AbstractAlthough glass plays an important role in medical facilities such as countertops or interfaces of medical equipment, where chemical and mechanical durability is of great concern, less attention has been paid to developing durable anti‐microbial surfaces. In the present work, silver‐containing surfaces were produced by ion exchange in soda‐lime silicate float glass, and the effects of residual surface compression produced by ion‐exchange on the release of silver ions were investigated. Silver‐doped surfaces were prepared by a sequential two‐stage ion‐exchange process in pure potassium nitrate, at 450°C for 4‐24 hours, and subsequently in KNO3+ 1 wt% AgNO3, at 400°C for 10‐30 minutes. Silver ions were found to penetrate 3‐5 µm into the glass surface, causing only a limited decrease in surface compression induced by potassium ions. The silver‐rich layer provides the required Ag+ leaching essential for anti‐microbial applications, as confirmed by Ag+ ion leaching tests. The silver release can be altered by surface compression.

Characterization of Glass, Shell, and Fishbone Beads on Ibo Island (Northern Mozambique) in the Context of the Indian Ocean Trade

A set of beads made of glass, gastropod mollusk shell, and fishbone from a Swahili occupation level on Ibo Island (northern Mozambique) is dated to the eleventh and twelfth centuries AD. The chemical composition of the glass beads and their chromophores, and the shell and fishbone materials, are studied to understand the local and trading provenance of these items. Representative samples of each material, including two flat glass shards, were characterized using optical microscopy, field emission scanning electron microscopy (FESEM) with energy dispersive X-ray (EDS) microanalysis attached, UV-Vis-NIR spectrophotometry, and X-ray diffraction (XRD). Glass beads represent 60% of the bead assemblage. The shell and fishbone beads are 38.75% and 1.25%, respectively. Three groups of glasses were identified: (1) mineral-soda alumina glass beads associated with the recently identified m-Na-Al 6 group that come from Western India; (2) vegetal-soda alumina, represented by one flat glass shard probably from the Middle East, and beads of v-Na-Al glass of type A that came from Central Asia; and (3) conventional soda-lime silicate glasses, of modern chronology and probable European origin. Groups 1 and 2 show a variety of chromophores, both ionic and colloidal. A ruby-color bead was also identified as belonging to the Na2O-ZnO-SiO2 system and colored with cadmium sulfoselenide colloids, but this was of modern chronology. Shell beads were made from Lambis lambis gastropod mollusk shells and were locally produced. The fishbone beads may have been from a cartilaginous fish of the Chondrichthyes class, but it is difficult to specify the taxonomical level. The results of the analysis suggest that Ibo Island was integrated very early into the Swahili trade networks of the Indian Ocean.

Synergetic effects of water and SO2 treatments on mechanical and mechanochemical properties of soda lime silicate glass

The synergetic effects of water and SO2 treatments on mechanical and mechanochemical wear properties of SLS glass were studied in this study. The results show that the nanomechanical properties (nanohardness and reduced modulus) as well as Vickers hardness and fracture toughness of treated SLS glass surface are increased, regardless of various treatment environments. After treated in dry SO2, the mechanochemical wear resistance of SLS glass in 40% RH becomes higher than pristine glass, but it doesnot change significantly in 70% RH. In contrast, after treated in wet SO2, the wear resistance of SLS glass in 40% RH decreases remarkably, and it shows much less wear resistance in 70% RH. This must be due to the change of glass surface structure and wear mechanism during the wear process. These results can provide deeper understanding of wear mechanism of glass and be helpful for operation process of functional and engineering glasses.

Effect of rice husk ash addition on the physical properties of soda-lime-silica glass for building glass and window panel

Demand for eco-friendly materials are increasing each year due to their excellent properties, which has proved to contribute in developing sustainable environment. One of the promising raw materials in producing glass is rice husk, a waste product from paddy harvesting, which contains about 90% of silica. Rice husks are usually burnt in an open area and contributed to serious air pollution problems. In this research, Soda-Lime-Silica Rice Husk Ash (SLRHA) glass which is a new combination of soda lime silicate (SLS) glass and rice husk ash (RHA) was developed for building glass and window application. The physical properties of the developed SLS-RHA glass system is presented in this paper. Based on the ultrasonic velocities test, sample with 5% of RHA was found to possess high and medium elastic properties including easy to bend rather than elongate, less stiff, tough at a certain direction and has low rigidity. Sample with 0% and 10% of RHA showed medium and poor elastic properties, respectively. High hardness value of the RHA glass was achieved using combinations of 60 to 120 Rockwell hardness test scale with up to 2% RHA. By considering the results from both tests, sample with 0% to 5% of RHA was considered to be the optimum formulation in the production of building glass and window panel.

Electrode Material Effect on the Flash Ignition in Soda-Lime Silicate Glass

The need for sustainable solutions to reduce the carbon footprint of the ceramics and glass industry leads towards the development of new electric current-assisted technologies. Flash sintering-like processes in glasses allow a reduction of the softening temperature and could pave the way for new shaping technologies. Herein, we investigated the flash transition in soda-lime silicate glass using two different electrode materials, silver, and platinum. The high dielectric strength registered on samples tested with platinum electrodes undergoes a significant reduction when silver is used. In other words, in the case of silver electrodes, the flash ignition takes place at a lower onset field. Moreover, the Joule heating developed during the process can be turned from being highly inhomogeneous with Pt electrodes to homogeneous when Ag electrodes are used.

Radiation shielding competencies for waste soda–lime–silicate glass reinforced with Ta2O5: experimental, computational, and simulation studies

In this study, the authors emphasized an incisive purpose as the valorization of waste soda–lime–silicate glass (SLS) for a potential gamma-rays shielding material. For this, xTa2O5-(100-x)SLS glass systems where x: 0, 0.005, 0.05, and 0.5 wt% were fabricated via conventional melting technique. The synthesized four glass specimens (RG and RGT1 to RGT3) were then subjected to physical, optical, and radiation shielding measurements. Simulation studies (MCNP-5) and theoretical computations (XCOM) were conducted to validate the findings. The results clearly showed that the insertion of Ta2O5 improved both physical and optical properties. In particular, RGT3, having a higher amount, possessed the highest glass density (ρglass) and refractive index (n) values. On the other hand, the transmission factor (TF) data revealed that increasing the thickness of the glass sample caused a notable decrease in the TF values. RG decreases from 92.233% to 78.461%, 61.562%, and 48.302% for thicknesses of 0.5 cm, 1.5 cm, 3 cm, and 4.5 cm. RGT3 shows the best radiation shielding potential out of the investigated waste SLS samples according to the several radiation shielding factors.

Optimization and semi‐automatic evaluation of a frosting process for a soda lime silicate glass based on phosphoric acid

AbstractChemical glass frosting processes are widely used to create visual attractive glass surfaces. A commonly used frosting bath mainly contains ammonium bifluoride (NH4HF2) mixed with hydrochloric acid (HCl). The frosting process consists of several baths. Firstly, the preliminary bath to clean the object. Secondly, the frosting bath which etches the rough light scattering structure into the glass surface. Finally, the washing baths to clean the frosted object. This is where the constituents of the preceding steps accumulate and have to be filtered from the sewage. In the present contribution, phosphoric acid (H3PO4) was used as a substitute for HCl to reduce the amount of ammonium (NH4+) and chloride (Cl−) dissolved in the waste water. In combination with magnesium carbonate (MgCO3), it allows the precipitation of ammonium within the sewage as ammonium magnesium phosphate (MgNH4PO4). However, a trivial replacement of HCl by H3PO4within the frosting process causes extensive frosting errors, such as inhomogeneous size distributions of the structures or domains that are not fully covered by these structures. By modifying the preliminary bath composition, it was possible to improve the frosting result considerably. To determine the optimal composition of the preliminary bath, a semi‐automatic evaluation method has been developed. This method renders the objective comparison of the resulting surface quality possible.

Modification of soda-lime silicate glass under corona poling in air and nitrogen atmosphere

Modifications of a soda-lime silicate glass under thermal poling in corona discharge (CDP) in air and in dry nitrogen is studied with micro Raman technique to evaluate the possibility of glass structuration using poling in nitrogen. It is shown that CDP in dry nitrogen, contrary to CDP in atmospheric air, increases the concentration of silicon-oxygen tetrahedra bound into three-member rings in the subsurface region of the glass. The formation of the three-member rings is accompanied by the release of molecular oxygen.

Nitrogen diffusion in silicate melts under reducing conditions

Abstract The behavior of nitrogen during magmatic degassing and the potential kinetic fractionation between N and other volatile species (H, C, O, noble gases) are poorly known due to the paucity of N diffusion data in silicate melts. To better constrain N mobility during magmatic processes, we investigated N diffusion in silicate melts under reducing conditions. We developed uniaxial diffusion experiments at 1 atm, 1425 °C, and under nominally anhydrous reducing conditions (fO2 ≤ IW-5.1, where IW is oxygen fugacity, fO2, reported in log units relative to the iron-wüstite buffer), in which N was chemically dissolved in silicate melts as nitride (N3–). Although several experimental designs were tested (platinum, amorphous graphite, and compacted graphite crucibles), only N diffusion experiments at IW-8 in compacted graphite crucibles for simplified basaltic andesite melts were successful. Measured N diffusivity (DN) is on the order of 5.3 ± 1.5 × 10−12 m2 s−1, two orders of magnitude lower than N chemical diffusion in soda-lime silicate melts (Frischat et al. 1978). This difference suggests that nitride diffusivity increases with an increasing degree of melt depolymerization. The dependence of N 3– diffusion on melt composition is greater than that of Ar. Furthermore, N3– diffusion in basalticandesitic melts is significantly slower than that of Ar in similarly polymerized andesitic-tholeiitic melts at magmatic temperatures (1400–1450 °C; Nowak et al. 2004). This implies that N/Ar ratios can be fractionated during reducing magmatic processes, such as during early Earth's magma ocean stages.

Determination of sulfur in soda-lime silicate glass by inductively coupled plasma atomic emission spectroscopy following separation using an alumina column

Determination of sulfur in soda-lime silicate glass by inductively coupled plasma atomic emission spectroscopy following separation using an alumina column

Light transfer through semi-transparent glass panes supporting pendant droplets

This paper quantifies experimentally the effect of pendant droplets condensed on the back of semi-transparent glass panes on their normal-hemispherical transmittance and reflectance in the visible and near-infrared. To enable sample characterization and ensure repeatability, acrylic droplets were deposited on the back side of 3 mm-thick soda-lime silicate glass slabs with or without hydrophobic surface treatment including perfluorinated silane, perfluorinated silane-coated silica nanoparticle monolayer, or Teflon coatings. The droplet contact angle θc was varied between 26° and 76° and the projected surface area coverage reached up to 60%. For contact angle θc smaller than the critical angle θcr for total internal reflection at the droplet/air interface, the presence of droplets did not significantly affect the normal-hemispherical transmittance and reflectance. However, for droplet contact angle θcr ≤ θc < 90°, the normal-hemispherical transmittance decreased significantly with increasing droplet contact angle and/or surface area coverage while the normal-hemispherical reflectance increased. The measurements of the normal-hemispherical transmittance were in excellent agreement with numerical predictions obtained from Monte Carlo Ray Tracing method. These results further validate our previous numerical simulations and the different optical regimes identified. The results of this study can provide guidelines for the design and operation of energy efficient flat-plate solar collectors, outdoor photobioreactors, greenhouses, solar desalination systems, and other solar energy conversion systems.