Hydrothermal synthesis of hydrated layered polysilicate magadiite from coarse quartz glass blocks

Abstract

We herein report a new method of synthesizing highly crystalline hydrated layered polysilicates (HLSs) using a coarse quartz glass block as a precursor. Magadiite, a type of HLS, is synthesized through hydrothermal reactions at 150 °C with a SiO₂/NaOH/H₂O ratio of ≈4.4/1.0/81.1. The results showed that when the particle size of the precursor was classified as <1000 µm, it was transformed into magadiite. However, if the particle size was larger than that, the precursor remained mostly in an amorphous phase. In addition, the hydrothermal reactions using finer precursors tended to result in the crystallization of by-products such as kenyaite and α-quartz. Hence, the particle size (s) of the quartz glass precursor suitable for synthesizing magadiite is 10 < s < 500 µm. This finding will contribute to a new method of synthesizing HLSs and related materials, e.g., their recycle synthesis with industrial quartz glass waste.