A review on microwave irradiation to the properties of geopolymers: Mechanisms and challenges

摘要

Geopolymer has been demonstrated as a promising candidate to replace Portland cement with less carbon footprint and energy consumption. The practical application of geopolymers is largely relying on strength development via the geopolymerization process. The application of microwave (MW) as an efficient auxiliary processing technology for geopolymers manufacture is emerging. Here in this paper, the fundamental mechanisms, influencing factors, and the potentials of microwave in geopolymer applications were reviewed. The capability of volumetric heating could generate significantly different heating patterns from traditional heating, therefore greatly reducing the processing time and enhancing the mechanical strength. The selective heating of certain ingredients with different dielectric properties would also benefit the immobilization of heavy metals in the geopolymer network, therefore facilitate solid waste disposal and recycle with significant environmental benefit. The current development of the promising microwave-assisted geopolymer strategy is mainly limited by the lack of large-scale microwave reactors. Future efforts to increase the energy conversion efficiency and processing capacity of MW reactors are critical before large-scale industrial applications.(c) 2021 Elsevier Ltd. All rights reserved.