There is a method in the classic textbook "Quantitative Inorganic Analysis", byA.I. Vogel, for 
Si in steel, which is like this apart from the initial dissolution steps, I am happy to send you a 
scan of the two pages if you want.

cheers
Ritchie Sims
Geology,
Auckland University

On 15 Jan 2010 at 8:36, Kluk, Dave wrote:

Steve,

I don't remember the ASTM method but the procedure used NaOH and H2O2 to
dissolve the sample in a large Nickel crucible. After dissolution it was
acidified with HNO3 and then Perchloric acid. After taking the solution
to fumes it was diluted with DI water and heated.
Final quantification was performed by filtering off the SiO2 and
igniting the precipitate and paper in a Pt crucible. Weight loss after
the use of HF was used for the calculation for the final quantification.

-----Original Message-----
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's).
[mailto:[log in to unmask]] On Behalf Of Steve D
Sent: Thursday, January 14, 2010 12:35 PM
To: [log in to unmask]
Subject: Silicon Gravimetric

I have had some trouble analyzing a high silcon aluminum casting sample
and 
wanted to know if you anyone remembers the gravimetric determination 
procedure for silcon.  I thought it was ASTM E364 but it is now 
unavailble.  Any suggestions?  can anyone supply me a copy of the
method?

thanks!

Steve