How does Perlite expand?
Two types of water, H2O and OH (a negatively charged water of hydration) are contained and internally bound in Perlite ore. When rapidly heated to an appropriate temperature, Perlite’s silicate structure softens and both types of water turn to steam, blowing or expanding the viscous mass into a glassy silicate bubble froth consisting of tiny closed air cells on the inside surrounded by an extremely large broken bubble surface structure. As an analogy, think of popping popcorn.
