Synthesis of wollastonite mineral by two reaction steps: hydrothermal and calcination reaction from rice hush and portlandite

Abstract

This research presents the synthesis process of wollastonite mineral by two reaction steps, hydrothermal and calcination, using Vietnam rice husk and portlandite. The rice husk ash after burning was batch mixed with Ca(OH)₂ with the Ca/Si molar ratio of 1.0, followed by hydrothermal treatment at 180^oC to obtain xonotlite mineral. The obtained xonotlite mineral was calcined at 900^oC for 5 hours to form a wollastonite owning fibre shape interlocked together to form an interconnected porous structure with a pore size of 1~2 µm, which could be suitable for industrial application.