Process for the preparation of crystalline sodium silicates
AssigneeHoechst Aktiengesellschaft
InventorsGunther Schimmel, Michael Kotzian, Reinhard Gradl
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Abstract
To prepare crystalline sodium silicates having a layer structure and the formula Na.sub.2 Si.sub.x O.sub.2x+1, in which x is between 2 and 3, sand and soda are first fused in a molar ratio of SiO.sub.2 /Na.sub.2 O of 2 to 3.5 at temperature of 1200.degree. to 1400.degree. C. The water-glass obtained in pieces after the melt has cooled is ground to particle sizes of less than 2 mm before it is treated at temperatures of 600.degree. to 800.degree. C. for 10 to 120 minutes in an elongated reaction zone with mechanical circulation. Finally, the material leaving the reaction zone is ground to a particle fineness of less than 1 mm.
Claims3
A process for the preparation of crystalline sodium silicates having a layer structure and the formula Na.sub.2 Si.sub.x O.sub.2x+1 in which x is between 2 and 3 consisting of the steps:
- a) fusing sand and soda in a molar ratio of SiO.sub.2 /Na.sub.2 O of 2 to 3.5 at temperatures of 1200.degree. to 1400.degree. C. with the resultant formation, after cooling the melt, of a lumpy water glass;
- b) grinding the lumpy water glass to a particle size of less than 2 mm;
- c) treating the ground water glass at temperatures of 600.degree. to 800.degree. C. for 10 to 120 minutes in an elongated reaction zone with mechanical circulation;
- and
- d) grinding the material leaving the reaction zone to a particle fineness of less than 1 mm.
Dependencies are inferred from the claim text.