sodium silicate
An alkaline salt, prepared by calcining
diatomaceous earth. quartz, or sand with sodium
hydroxide or sodium carbonate. The salt consists
of varying proportions of sodium oxide and silica.
such as Na 2 SiO 3 . It is
used in the manufacture of paper for improving
physical tests, increasing the retention of fine
particles, and pH control. In this final use, it
provides another means of increasing alumina in
the stock preparation system. one that is
accomplished by raising the pH value of the stock,
thereby forcing the use of additional alum to
lower the pH. Also called "water glass." (98 , 235 )
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