Papers by Keyword: Thailand Quartz Sand

Abstract: Ecological crystal glass with no toxic compounds, especially lead, was based on soda-lime-silica glass that fabricated mainly from 50 wt% local dressing sand, 22 wt% barium carbonate and doped with various concentrations of zirconium dioxide. Density (ρ), refractive index (RI), thermal expansion coefficient (CoE) and hardness (HV) were measured. It was found that the values of ρ, RI and HV increased linearly as the increasing of zirconium dioxide contents, whereas the CoE was decreased. This type of glass was ecologically friendly material.

Abstract: Lead glass that shows a high refractive index is the best known and most popular for radiation shielding glass. Due to the toxic of lead compounds on the human organisms as well as the environmental issues, lead free glass was fabricated by using some heavy elements such as barium and bismuth to replace lead. In this study, colorless lead free glass samples were prepared from 40 wt% local quartz sand and various concentration of BaCO3 (20-40 wt%) as the main compositions in order to study radiation shielding property. The glass mixtures were melted conventionally using electric furnace at the maximum temperature of 1250°C with 4 hr dwelling time. The gamma attenuation characteristics were studied for the photon energy of 662 keV from Cs-137. Density and refractive index were also determined. It was found that a variation of prepared glass samples can be produced both in terms of clarity and radiation shielding properties. The attenuation coefficients were linearly increased as the increase of BaCO3 content. The density and refractive index were also increased. The linear and mass attenuation coefficients of the glass sample containing 40 wt% BaCO3 were 0.234 cm-1 and 0.0726 cm2g-1. In conclusion, a low density glass samples will give rise less attenuation than a high density ones. It can be concluded that the lead-free high refractive index glass that is one of the environmental materials can be used as the gamma radiation shielding glass.

Abstract: Soda-based glass samples were fabricated in a laboratory scale using quartz sands that was a by-product of feldspar floatation in Tak Province, northern Thailand, and 25-wt% commercial-grade Na2CO3 as the main compositions. Fe2O3 of 0.1 to 10.0 wt% concentrations was doped into the glass mixture. Well-mixed and dried powders were melted in a ceramic crucible for 6 h at 1250°C using an electric furnace. Transparent and bubble-free glass samples were obtained as results. It was found that Fe2O3 dopant turned the otherwise colorless glass to dark brown. Dielectric property and physical properties, such as, color, specific gravity, and refractive index of the glass samples were studied. The samples’ dielectric constant, specific gravity, and refractive index increased with increasing Fe2O3 doping concentration. UV-VIS-NIR and synchrotron-based X-ray absorption spectra were measured and discussed.