(ABSTRACT) Several novel silica structures have been generated using a simulated-annealing strategy with an ab-initio based covalent-bonding potential. First-principles total-energy pseu-dopotential methods have been used to examine several promising novel structures and to compare their structural parameters, cohesive energies and bulk moduli with those of low-quartz, low-cristobalite, silica-...

perlite or pearl stone is a natural glass which has formed by rapid cooling of viscous lava or magma. perlite is mainly composed of silica, aluminum, potassium and sodium. in this experiment, perlite was used as a low-cost source of si and al to synthesis of sodalite zeolite using the alkaline hydrothermal treatment. a statistical taguchi design of experiments was employed to evaluate the effec...

Franzinite, ideally [(Na,K)30Ca10][Si30Al30O120](SO4)10•2H2O, a feldspathoid belonging to the cancrinite group, has a tenlayer stacking sequence. Its structure was solved in the space group P321 to an R value of 5.96%. Cell parameters are a 12.916(1), c 26.543(3) Å. The framework, characterized by the stacking sequence ABCABACABC, contains regular alternations of two “cancrinite” and two “sodal...

Introduction: The search for the former existence in the Early Solar System of the now extinct radionuclide Cl (T1⁄2 = 3x10 a) has proven to be difficult [e.g., 1]. This is at least partly due to the volatility of chlorine and the fact that in primitive meteorites Cl occurs in high abundance only in alteration phases such as sodalite (Na8Al6Si6O24Cl2). 36-Cl decays to both Ar by β decay (98.1 %...

In this paper, we present the possibility of using fly ash to produce synthetic zeolites. The synthesis class F fly ash from the Stalowa Wola SA heat and power plant was subjected to 24 h hydrothermal reaction with sodium hydroxide. Depending on the reaction conditions, three types of synthetic zeolites were formed: Na-X (20 g fly ash, 0.5 dm(3) of 3 mol · dm(-3) NaOH, 75 °C), Na-P1 (20 g fly a...

The structural behavior of a chromate aluminate sodalite, Ca8[Al12O24](CrO4)2, at room pressure and on heating from 463 to 982°C was determined by using in situ synchrotron X-ray powder-diffraction data [ = 0.91997(4) Å] and Rietveld refinements. The sample was heated at a rate of about 9.5°C/min., and X-ray traces were collected at intervals of about 17°C. The structure at 463°C is a modulated...

The diffusion of hydrogen in sodium aluminum sodalite (NaAlSi-SOD) is modeled using classical molecular dynamics, allowing for full flexibility of the host framework, in the temperature range 800-1200 K. From these simulations, the self-diffusion coefficient is determined as a function of temperature and the hydrogen uptake at low equilibrium hydrogen concentration is estimated at 573 K. The in...

Perlite or pearl stone is a natural glass which has formed by rapid cooling of viscous lava or magma. Perlite is mainly composed of silica, aluminum, potassium and sodium. In this experiment, perlite was used as a low-cost source of Si and Al to synthesis of sodalite zeolite using the alkaline hydrothermal treatment. A statistical Taguchi design of experiments was employed to evaluate the effec...