ABSTRACT
Preparation of PSA . . . . . . . . . . . . . . . . . . . . . . . . 38
Appendix I: Preparation of PSA 5% SiO2 . . . . . . 38
Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Silicic acid can be in the form of a monomer or in the form
of low molecular weight polymeric units. Monomeric
silicic acid Si(OH)4 has not been isolated or obtained in
a concentrated solution without considerable polymeri-
zation, therefore is not a practical form to use in catalyst
slurries to spray dry. Also not very practical is silicic
acid formed in a way that does not separate it from the
electrolyte products of the forming reaction. Residual elec-
trolytes increase the ionic strength of the solution and
result in destabilization followed by premature gelling of
the silicic acid.
