Abstract—In this study, we attempted to continuously treat waste perlite dust by alkali fusion using a rotary kiln, to synthesize faujasite zeolite. A mixture of perlite dust and sodium hydroxide (NaOH) powder with three different mixture ratios (by weight) of 1:0.5, 1:0.8, and 1:1 was charged into a rotary kiln, and heated at 380 °C or 450 °C for 30 min. The resultant fused material was then converted into faujasite, a zeolite product, by heating it at 80 °C for 12 h followed by shaking for 24 h in distilled water at room temperature. It was confirmed that sodium silicate was formed using the rotary kiln, and the dissolution of Si and Al in the fused dust increased with increasing NaOH addition near the exit of the kiln. Faujasite could be synthesized for all fused conditions, and the cation exchange capacity (CEC) of the product increased with increasing NaOH addition, especially at close to the exit of the kiln. Varying amounts of the dust ranging from 0.1 to 1 g fused with NaOH (1:1) at 380 °C for 30 min using the rotary kiln were added to 2 mL of distilled water, shaken for 12 h at room temperature, and subsequently heated at 80 °C for 6 h to examine the effect of the solid/liquid ratio on the synthesis of zeolites from the fused dust. Regardless of the solid/liquid ratio, the amorphous material was formed after shaking at room temperature. Faujasite could be synthesized from the solution above a solid/liquid ratio of 0.25 g/mL, and the peaks of faujasite from the solution at 0.25 g/mL were higher than those at 0.5 g/mL.
Index Terms—Alkali fusion, faujasite zeolite, rotary kiln, waste perlite dust.
Takaaki Wajima is with the Department of Urban Environment Systems, Graduate School of Engineering, Chiba University, Japan (e-mail: wajima@tu.chiba-u.ac.jp).
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Cite: T. Wajima and S. Onishi, "Alkali Fusion of Waste Perlite Dust to Synthesize Faujasite Zeolite Using a Rotary Kiln," International Journal of Chemical Engineering and Applications vol. 10, no. 6, pp. 184-188, 2019.
