Inorganic thermal insulation material prepared from pitchstone

Abstract Although pitchstone (Ps) can be used to construct expanded and vitrified small balls (EVSBs) for building thermal insulation materials, the processing of the EVSBs requires substantial amounts of energy and produces many unusable tailings. The complete utilization of Ps resources in an energy-efficient manner is still challenging. In this study, a novel inorganic thermal insulation board was prepared by Ps powder through a chemical foaming method at room temperature and heat treatment method at 400 °C. The influence of sodium silicate solution on Ps powder mass ratio, surfactant content, foaming agent dosage, and that of low-temperature heat treatment process on the performance of the samples of the insulation material were systematically studied. Accordingly, the thermal conductivity (TC), density, and compressive strength (CS) of the samples could be engineered in the 0.114–0.270 g/cm3, 0.051–0.086 W/(m·K), and 0.12–1.46 MPa ranges, respectively, by modifying the abovementioned factors. Therefore, this work provides an energy-efficient way for the complete utilization of Ps resources.