# How do I perform a gravimetric analysis of Portland cement?

To determine the silica ($\ce{SiO2}$) content in Portland cement by gravimetric analysis it is digested in $\ce{HCl}$ and the silica residue is eventually measured.

The chief constituents are $\ce{Ca2SiO4}$ (or $\ce{2CaO.SiO2}$), $\ce{4CaO.Al2O3.Fe2O3}$, $\ce{Ca3(AlO3)2}$ (or $\ce{3CaO.Al2O3}$), and $\ce{CaSiO3}$ (or $\ce{CaO.SiO2}$). Gypsum is also present. What species are present in solution after the $\ce{HCl}$ has reacted with the cement? I assume $\ce{CaCl2}$ and $\ce{H2O}$ would be present, but would $\ce{AlCl3}$ also form? How would I approach this problem?