Heavy metals immobilization follows two steps:
First: dissolution, solubilization of the heavy metal, due to high pH (no precipitation as hydroxides);
Second: charge balancing role like any cations (Na or K).
Immobilization is not encapsulation, but regular geopolymerization.
These steps are disclosed in French in the published International patent application WO 89/02766, titled “Method for stabilization, solidifying and storing waste materials” published with modified claims and declaration, dated 05.05.1989. This was a second publication. Initial publication of WO 89/02766 dated 06.04.1989 did not contain this information.
Prof. Joseph Davidovits