Process for preparing sodium silicates

For the preparation of crystalline sodium silicates having a layer structure, an SiO2/Na2O molar ratio of (1.9 to 2.1):1 and a water content of less than 0.3% by weight from a waterglass solution obtained by reacting sand with sodium hydroxide solution in an SiO2/Na2O molar ratio of (2.0 to 2.3):1 a...

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Bibliographic Details
Main Authors KOTZIAN MICHAEL, WINGEFELD GERD, TAPPER ALEXANDER, SCHIMMEL GUENTHER
Format Patent
LanguageEnglish
Published 28.02.1995
Edition6
Subjects
CHEMISTRY
COMPOUNDS THEREOF
INORGANIC CHEMISTRY
METALLURGY
NON-METALLIC ELEMENTS
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Summary:For the preparation of crystalline sodium silicates having a layer structure, an SiO2/Na2O molar ratio of (1.9 to 2.1):1 and a water content of less than 0.3% by weight from a waterglass solution obtained by reacting sand with sodium hydroxide solution in an SiO2/Na2O molar ratio of (2.0 to 2.3):1 and having a solids content of at least 20% by weight, the waterglass solution is treated in a spray-drying zone with hot air at 200 to 300 DEG C to form a pulverulent, amorphous sodium silicate having a water content (determined as loss on ignition at 700 DEG C) of 15 to 23% by weight. The pulverulent, amorphous, water-containing sodium silicate is first ground, preferably to grain sizes of 1 to 50 mu m, before it is introduced into a rotary kiln in an inclined arrangement and treated therein with flue gas in countercurrent at temperatures of more than 500 to 850 DEG C, to form crystalline sodium silicate. The sodium silicate emerging from the rotary kiln is first comminuted to grain sizes of 0.1 to 12 mm and finally ground to grain sizes of 2 to 400 mu m.
Bibliography:Application Number: SI19920010216