Recovery of diverse solid wastes into porous materials via thermal processing: Review of melt structure, processing parameter, and application

Converting multiple solid wastes into sustainable porous materials via thermal processing is a practical approach to beneficially recycling waste and reducing landfill burden. The resulting value-added products have great potential as insulation and lightweight materials for construction purposes. The properties of these waste-based porous materials (WBPM) are mainly determined by the thermal process, specifically the high-temperature matrix properties and the gas evolution process. This review provides insights into the key factors affecting the melt structure of the matrix and the gas, from the perspective of the composition of starting materials, thermal treatment conditions, and additives. In particular, the effects of the main oxide components constituting solid waste on the melt structure and crystallisation are analysed. The conventional and novel applications of WBPM are summarised and discussed. These insights provide significant information for facilitating the highly efficient utilisation of solid wastes into value-added porous materials on a large scale.