Sodium alumino silicate

Molecular sieves are sodium alumino-silicates (zeolites) that have well-defined pore sizes. The 4A size adsorbs water to the exclusion of almost all organic substances and is a fast and effective drying agent, but like Drierite it is impossible to ascertain by appearance whether enough has been used. MoleculcU sieves in the form of 1/16-in. pellets are often used to dry solvents by simply adding them to the container. 

Anhydrous Sodium Alumino silicate Anhydrous Calcium Alumino silicate Anhydrous Alumino silicate... 

Explain the process of dissolution of a sodium trisilicate glass in water. Explain the effect of pH on the process. Explain why a sodium alumino-silicate glass is more durable than a sodium silicate glass in water, but is less durable in a strong acid. 

McKeown, D. A., Galeener, F. L., and Brown Jr., G. E. (1984) Raman Studies of A1 Coordination in Silica-rich Sodium Alumino-silicate Glasses and Some Related Minerals, J. Non-Cryst. Solids, 68, 361-378. 

McKeown, D. A. (1987) Radial Distribution Analysis of a Series of Silica-rich Sodium Alumino-silicate Glasses Using Energy Dispersive X-ray Diffiaction, Phys. Chem. Glasses, 28, 156-163. 

The sodium alumino-silicate glass shown in Figure 17c alters glass structure and reduces Ne penetration. The A1 ions close the open structure by removing the NBO caused by the Na ions. The Na ions associate with the BO near the A1 ions. Thus, the open structure caused by the Na ions (and NBO) is removed by the A1 and yet the blocking effect of the Na ions remains. These two combine to inhibit Ne penetration (Kohler and Garofalini 1994). 

Webb EB, Garofalini SH (1994) Effect of adsorption of EAM metal atoms on the structure of a sodium alumino-silicate glass surface a molecular dynamics simulation. Surf Sci 319 381-393... 

McCormick AV, Bell AT, Radke CJ (1986) Application of 29Si and 27A1NMR to determine the distribution of anions in sodium silicate and sodium alumino-silicate solutions. In Murakami Y, lijima A, Ward JW (eds) Proceedings of the 7th international zeolite conference. Elsevier, Amsterdam, p 247... 

Figure 2 contains images that reveal the microstructural differences between the bonded, vibro-cast, and fused-cast AZS refractories. The microstructure of the fusion-cast AZS material is a mixture of corundum and zirconia co-precipitates, isolated zirconia dendrites, and a sodium alumino silicate... 

Sodium alumino-silicate (zeolite), having a larger pore size than 0,5 nm, thus producing lower retention times and less resolution 28.6% (mass/mass) water capacity. 

Beryllium is extracted from the main source mineral, the alumino-silicate beryl, by conversion to the hydroxide and then through either the fluoride or the chloride to the final metal. If the fluoride is used, it is reduced to beryllium by magnesium by a Kroll-type reaction. The raw metal takes the form of pebble and contains much residual halides and magnesium. With the chloride on the other hand, the pure metal is extracted by electrolysis of a mixture of fused beryllium chloride and sodium chloride. The raw beryllium is now dendritic in character, but still contains residual chloride. 

Studies regarding the reactions between sodium carbonate and potassium carbonate vapors and refractories have been limited in scope. (Many studies conducted by industry may not have been reported in the literature.) The majority have involved the examination of the degenerated features of refractories after an average service campaign. Most of the articles published have concerned the reactions between alkalies and alumino-silicate refractories utilized in glass melting and blast furnaces. 

All coals contain some sodium combined in the alumino-silicate species which will remain largely involatile in the flame. The ratio of the silicate sodium to non-silicate sodium varies over a wide range. The alkali-metal is present chiefly in the silicates in low chlorine bituminous coals. In the high chlorine bituminous coals and in many lignites and sub-bituminous coals it is present mainly in a flame volatile form. 

Some potassium sulphate can also be formed via the two routes. Potassium is present in coal chiefly in the form of potassium alumino-silicates (Table I) and a large part of the alkali-metal will remain involatile in the flame heated silicate particles. Some 5 to 20 per cent of the potassium is released for sulphation (24) which takes place partly at the surface of the parent particles (25) and partly via the volatilization routes as described above. However, sodium sulphate content of fly ash heated in pulverized coal flame, and chimney solids is always higher than that of potassium sulphate. 

Bituminous coals usually leave a highly silicious ash on combustion. That is, fused alumino-silicates constitute an acidic media at high temperatures that is capable of absorbing large quantities of basic metals in the form of oxides, chiefly those of sodium, calcium and... 

Mesoporous alumino silicate molecular sieves with MCM-41 type structure synthesized using various A1 sources (i.e. aluminum sulphate, aluminum isopropoxide, pseudo boehomite and sodium aluminate) have been used as supports for Ni - Mo catalysts. The HDN of o-toluidine tmd cyclohexylamine was studied in a fixed bed flow reactor at 450°C and PH2 = 1 atm. The activity per unit of weight of the MCM - 41 supported catalysts was evaluated and compared to that of supported catalysts preptu ed by sequential impregnation method. The XRD and DRS data have been used to explain the observed trend in catalytic activity towards HDN reaction... 

Table 10.2 summarizes some examples of zeolites based on their classification by chemical composition. Low-silica zeolites (Si/Al < 5) are synthesized in basic conditions (pH >13) using a silicon source, an aluminum source, and alkali hydroxides at moderate temperatures, typically less than 120°C. The identity of the alkaU species used is a determining factor in which phase is obtained from synthesis, as the relative rates of (alumino)silicate hydrolysis and condensation reactions are dependent on the identity of the alkali cation. It is also believed that hydrated alkali cations effectively direct the assembly of (alumino)silicate precursors into fuUy connected three-dimensional structures. Sodium and potassium hydroxide have been used most frequently in low-silica zeolite syntheses due to their low cost and high solubility in... 

Titration of hydrochloric acid, containing the same amount of aluminum chloride as in 2, with sodium silicate (alumino-silicate complex formed)... 

The only ones that have so far found practical application in glass-ionomers for dentistry are alumino-silicate glasses, with fluoride and phosphate additions. These are typically calcium based, with some extra sodium, though successful commercial materials exist in which calcium has been wholly or partly replaced by strontium. 

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