Results of dissolution of DE and RHA in 10 M NaOH activator
solution are shown in Table 3. As expected, the dissolution correlated
well with particle size and fineness of DE. The amount of
leached silicon ion of CDE was 2040 mg/L and increased to 2110
and 2750 mg/L, respectively, for finer DE and FDE. The finer DE
possessed high surface area and allowed greater contact with the
alkali solutions. Furthermore, fine DE also contained higher silica
content and less alumina content compared to the coarser ones
(Table 1). The SiO2/Al2O3 ratio of dissolved species thus increased
with an increase in fineness. For the calcined DE,