Wow, that's a lot of dollar signs. Silica is an amorphous polymer of polysiloxane units. Small amounts may be assimiliated if there is enough HCl present in the gut, or unless Si is in an organic form, such as occurs in horsetail grass. But SiO2 will require strong stomach acid. However, keep in mind that the strongest HCl (37% wt. is stored in ---- glass bottles. I can't see how 5% silica can counter alum. Look at the MSDS for alum and see if silica is listed as an antidote. I've seen lots of good articles written since 1950, off the top of my head, Rath, Pauling, Krebs, Moss, Livingtson-Wheeler, Gerson, Becker. As far as yttrium goes, it is a tri-positive cation, that forms compounds analogous to aluminum, which is zeta-destroying in large amounts, and albumin consumptive in smaller.
I'm not attempting to incite a debate, rather to share an alternate perspective of opinion.