Alkali silicate

Alkali silicates are characterized by the weight or molar Si02 alkali oxide ratio 

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The alkali silicates are soluble in water and are used industrially. See sodium silicates. 

The viscosity and non-Newtonian flooding characteristics of the polymer solutions decrease significantly in the presence of inorganic salts, alkali silicates, and multivalent cations. The effect can be traced back to the repression of the dissociation of polyelectrolytes, to the formation of a badly dissociating polyelectrolyte metal complex, and to the separation of such a complex fi"om the polymer solution [1054]. 

Alkali silicate glasses, 12 571-572, 584, 585 studies of, 12 577 Alkali silicates, 22 452... 

Crystal lattice packing, 12 249-250 Crystal lattice vibrations, 14 236 Crystalline adsorbents, 1 586, 589. See also Molecular sieves Zeolites for gas separation, 1 631 properties and applications, l 588t Crystalline alkali silicates, atomic structure of, 22 454-455 Crystalline cellulose, 5 373-379 Crystalline epoxy resins, 10 373-374 Crystalline flake graphite, 12 793 manufacture and processing of, 12 781-784... 

Sears 189) and Heston et al. 190) used the adsorption of sodium hydroxide for the determination of the surface area of colloidal silica. An empirical factor was used for the conversion of alkali consumption into surface area. This is permissible provided the packing density of surface silanols is constant. The determination was performed in concentrated sodium chloride solution in order to keep down the dissolution of silica. Using the same technique, it was found in my laboratory that all surface silanol groups as determined by other methods are neutralized at pH 9.0. At higher pH, siloxane bonds in the surface were opened. A maximum in the sorption of Na+ ions occurred usually at pH 10.5-10.6 which corresponded to a packing density of ca. 5 OH/100 A. On further addition of alkali, silicate ions H3Si04 went into solution. 

A number of reagents containing oxide components are used in zeolite manufacture [19]. Silica is provided by addihon of sodium or other alkali silicate solutions, precipitated, colloidal, or fumed silica, or tetraalkylorthosihcate (alkyl = methyl, ethyl) and certain mineral silicates such as clays and kaolin. Alumina is provided as sodium aluminate, aluminum sulfate soluhon, hydrous aluminum oxides such as pseudo boehmite, aluminum nitrate, or aluminum alkoxides. Additional alkali is added as hydroxide or as halide salts, while organic amines and/or... 

Kurkjian C. R. and Russel L. E. (1958). Solubility of water in molten alkali silicates. Jour. Soc. Glass Technol, 42 130-144. 

Nath P. and Douglas R. W. (1965). Cr /Cr equilibrium in binary alkali silicate glasses. Phys. Chem. Glasses, 6 197-202. 

Both lithium and barium salts reduce expansion based on alkali-silicate and alkali-carbonate swelling through the osmotic pressure development mechanisms. Two theories have been postulated [5, 11]. According to the first mechanism, soluble metal silicates, formed by the attack of alkali hydroxides on silica, are said to convert to insoluble lithium silicates in the presence of lithium salts. Consequently, less water is imbibed and this results... 

Dran, J.-C., Della Mea, G., Paccagnella, A., Petit, J.-C. Trotignon, L. 1988. The aqueous dissolution of alkali silicate glasses Reappraisal of mechanisms by H and Na depth profiling with high energy ion beams. Physics and Chemistry of Glasses, 29, 249-255. 

Pederson, L. R., McGrail, B. P., McVay, G. L., Petersen-Villalobos, D. A. Settles, N. S. 1993. Kinetics of alkali silicate and aluminosilicate glass reactions in alkali chloride solutions Influence of surface charge. Physics and Chemistry of Glasses, 34, 140-148. 

Solutions of monosilicic acid may also be obtained by careful hydrolysis of tetrahalo-, tetraalkoxy-, or tetraacyloxysilanes by electrolysis or acidification of alkali silicate solutions or by ion exchange (qv). By operating under carefully controlled conditions at low temperature and pH, solutions may be obtained that remain supersaturated with respect to amorphous silica for hours at temperatures near 0°C. Eventually, however, polymerization reactions involving the formation of siloxane linkages occur, leading ultimately to the formation of colloidal particles and further aggregation or gel... 

Some important features regarding the structures of liquid silicates are revealed by recent volumetric studies of both alkali (9) and alkaline earth systems 55). First, the partial molar volume of silica in the alkali silicates is nearly equal to that of pure fused silica and is independent of the cation over wide compositional ranges. Second, at about 10 15 mole-% metal oxides, the thermal expansions show a sudden increase. The results for the alkali silicates are shown in Fig. 5. A similar behavior is found in the system... 

Hirayama and Lewis (131) studied the fluorescent decay of the 3/2 state of neodymium in a very large number of alkali silicate and alkali germanate glasses. Data were taken by exciting a flat sample with a xenon... 

Fluorescent and Physical Properties of Neodymium-Doped Alkali Silicate and Germanate Glasses... 

In the alkali silicate glasses, the decay time appears to increase with increasing ionic radius of the alkali metal modifier. The decay time also increases with increasing silica content, and apparently reaches a saturation value of 1.03 msec at a silica content of about 85 mole per cent. Figure 37 shows this result. 

No. Refractory Type SK)2 AI2Os Fe203 HOj, CaO MgO Cr203 SiC Alkalies Siliceous Steel-Slag Resistance to High-iime Fused Steei-Slag Mill-Scale Coal-Ash Slag... 

Titanium-containing materials have been synthesized from strongly alkaline suspensions obtained by mixing TiCU with alkali silicate and sodium aluminate solutions. The gel obtained was homogenized and mixed in an autoclave at... 

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