Evidence for non-thermal microwave effect in processing of tailing-based glass-ceramics

Tailing-based glass-ceramics were crystallized via conventional and microwave heating at 720 degrees C for 30 min and 820 degrees C without holding and compared in order to obtain evidence for a non-thermal microwave effect. The comparative analytical results showed that the microstructural uniformity was greatly enhanced and the crystallization activation energy was significantly reduced by microwave processing compared to conventional heating, suggesting accelerated grain growth during crystallization. Microwave radiation affected the crystal orientation and induced corresponding changes in the Si-O bond lengths and Si-O-Si angles, thus enhancing the formation of the diopside crystal structure. In addition, the samples under microwave processing exhibited superior physicochemical performance, including greater relative density, bending strength, microhardness, and resistance to acids and alkali, compared to conventionally processed samples. All these results provided positive evidence supporting the existence of a genuine microwave non-thermal effect, allowing deepened understanding for fine control over microwave-assisted metallurgy.