Preparation of solid, crystalline, substantially anhydrous sodium metasilicate

• Main Author: JUST; GUENTHER
• Format: Patent
• Language: English
• Published: 04.01.1983
• Subjects: CHEMISTRY; COMPOUNDS THEREOF; INORGANIC CHEMISTRY; METALLURGY; NON-METALLIC ELEMENTS

This invention relates to the preparation of sodium metasilicate. More particularly, this invention relates to a process for the preparation of solid, crystalline, substantially anhydrous sodium metasilicate which comprises the steps of: (a) reacting an SiO2-containing material with a concentrated aqueous solution of sodium hydroxide in an SiO2 to Na2O molar ratio of from about 1.2:1 to 1:1.2 under elevated pressure and at an elevated temperature, to form a sodium metasilicate suspension; (b) filtering the suspension from step (a) to obtain a filter cake and filtrate; (c) crushing the filter cake from step (b) at elevated temperature; (d) removing water from the crushed filter cake to recover substantially anhydrous sodium metasilicate; (e) concentrating the filtrate from step (b); and (f) returning the concentrated filtrate from step (e) to the reaction mixture of step (a).