Silica is a problem for high pressure boilers.
It exhibits enough volatility that high
pressure boilers will have silica carry
over to the vapor partition. When the
steam pressure is reduced in the turbines,
the silica will precipitate on the
blades as a glassy deposit which reduces
efficiency. Both types of silica,
colloidal and reactive, can cause this
problem as colloidal silica will break
down and volatilize under high temperature
and pressure.