Hydrothermal solidification of green tuff / tobermorite composites

Abstract

Mesoporous green tuff / tobermorite composites were synthesized by hydrothermal treatment of powder compacts consisting of waste green tuff and slaked lime. XRD results showed that chlorite, the mineral responsible for the green coloration of green tuff, remained after hydrothermal treatment. Tobermorite formed as a result of a reaction between the quartz inherent in green tuff and slaked lime. The formation of tobermorite led to an increase in bending strength, reaching 12 MPa after 10 h of hydrothermal treatment, as well as to an increase in specific surface area and mesopore volume. The composite adsorbed a greater quantity of water vapour and ammonia gas than waste green tuff.