An overview on microwave processing of material: A special emphasis on glass melting

ABSTRACT

Material processing adopting microwave heating has emerged as an alternative tool owing to faster processing, a cleaner environment, and several other advantages. This review provides a summary of recent reports of microwave synthesis of materials. This study reviews the use of microwave energy for application in several material processing technologies apart from food processing. A special emphasis has been made in the processing of glass adopting microwave energy. Melting of glass comprising SiO₂, P₂O₅, B₂O₃ as the main building block has been discussed. It has been revealed that silica, a microwave transparent material as reported earlier, can be heated under microwave heating directly. Microwave absorption of raw materials and different glass system has been discussed. Dielectric properties, particularly loss tangent or loss factor, are presented for some glass composition. Less evaporation of ingredient and low contamination from the crucible wall are noticed during glass melting using microwave heating. Enhanced iron redox ratio (Fe⁺²/∑Fe) in microwave processing may be considered an advantage in the preparation of heat absorbing filter glass. Small-scale glass melting using the microwave heating has a significant impact on energy and time saving. However, the challenges associated with the upscaling glass melting with microwave heating and future scope have been talked about.

KEYWORDS:

• Absorption
• alumino-phosphate
• borate
• borosilicate
• furnace
• glass
• heating
• magnetron
• material
• melting
• microwave
• processing
• silica

Acknowledgments

Authors are thankful to the Director, CSIR-CGCRI, for his kind support and encouragement to pursue this work. The authors are sincerely thankful to the reviewer for his suggestions to improve the quality of the article.