This study aims to investigate the impact of the raw material total moisture content during the manufacturing process on the performance of volcanic glass powder (VGP) in order to reduce the environmental impact. The results showed that when the raw material was sorted in a total moist state of around 6%, the recovery rate of volcanic glass remained unchanged compared to the dry state. Although the possibility of weathering material contamination was confirmed, the analysis of chemical composition, specific surface area, and the activity index test of VGP all met the requirements of JIS standards.
