| abstract |
Disclosed is a lightweight silicate aggregate produced by the steps of mixing together dry rice hull ash, an alkali metal hydroxide, boric acid, and water; heating the mixture to a temperature sufficient to initiate reaction; curing the composition at a temperature less than the boiling point of water until the reaction is complete; comminuting the cured product and heating the comminuted product to form the expanded aggregate. The expanded aggregate is useful as, inter alia, a sorbent, filler, energy insulator or filter. |