Synthesis of Mullite from Laboratory Waste Silica through Transferred Arc Plasma Processing Method

Abstract

Transferred arc plasma (TAP) processing could be an economic and time saving processing method for waste treatment and recycling of chemical laboratory solid wastes. In this work, three different waste silica powders derived from chemical laboratories which are adsorbed with catalytic amount of ruthenium, palladium, and ferrocene derivatives are recycled in addition with alumina to form mullite (3Al₂O₃·2SiO₂) by TAP processing technique and as well as in conventional method for comparison. The phase and microstructure formation of the processed samples were analyzed by X-ray diffraction (XRD) pattern and scanning electron microscopy (SEM) images, respectively. The results show that palladium adsorbed silica has significantly enhanced the formation and densification of mullite rather than ruthenium- and ferrocene-adsorbed silica in TAP processing. The SEM images show that the different kinds of microstructures developed in plasma arc processing mullite due to the direction of the plasma arc formation and solidification.

Keywords:

• Mullite
• Plasma
• Recycling
• Silica
• Treatment

ACKNOWLEDGMENTS

The authors acknowledge the project funding from the Department of Science and Technology, Government of India. Authors would like to thank Mr. Janarthanan Nair (Ion Arc Technologies Pvt., Ltd., India) for their help in developing torch facilities. One of the authors (S.Y.) acknowledges the Junior Research Fellowship awarded by Department of Science and Technology, Government of India.