Preliminary Evaluation of a Base-Extraction Gamma-Al2O3 Synthesis Route from Indonesian Kaolin

Tjokorde Walmiki Samadhi, Subagjo, Kevin R. Lismana, Khasin Fuadi

Chemical Engineering Program
Faculty of Industrial Technology, Bandung Institute of Technology
Jalan Ganesha 10, Bandung 40132
Email: twsamadhi@che.itb.ac.id

Kaolin has been identified as a potential raw material for the production of g-Al₂O₃ for hydrotreating catalyst support. This work explores the technical feasibility of applying the potassium hydroxide (KOH) extraction synthesis route on kaolin from the Belitung Island in Indonesia. The application of a published synthesis method to Belitung kaolin requires an approximately twofold increase in kaolin calcination time, an increase in kaolin calcination temperature from 950 to 1000^oC, and a tenfold increase in metakaolin extraction time, to obtain a specific surface area higher than 200 m²/g. The highest specific surface area of 233 m²/g was obtained when the kaolin was calcined at 1000oC for 24 hours, and the metakaolin was extracted by concentrated KOH solution for 12 hours. Phase characterization of the final product confirmed the formation of g-Al₂O₃, but with the inclusion of low-surface area a-Al2O3 phase.

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