Rapid fabrication of coal gangue-based alkali activated foams and application as pH regulators

High porosity coal gangue-based alkali activated foams were synthesized by an efficient microwave foaming route within 3 min. The porosity, density, porous structure and compression strength of the foams produced using different microwave power settings, together with their use as pH regulators, were evaluated. The alkaliactivated foams with 100 % coal gangue as the mineral constituent can be used for pH buffering applications, while simultaneously providing a high value-added route to reuse the solid waste.