A study on the preparation of fine and low soda alumina

• Published in: International journal of mineral processing Vol. 80; no. 2; pp. 126 - 132
• Main Authors: Park, Yi Yong, Lee, Suong Oh, Tran, Tam, Kim, Seong Jun, Kim, Myong Jun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2006
• Subjects: activated alumina; aluminium trihydroxide; bayer process; fine alumina; low soda alumina; bayer process; low soda alumina; fine alumina; activated alumina; aluminium trihydroxide
• ISSN: 0301-7516; 1879-3525
• DOI: 10.1016/j.minpro.2006.03.006

A simple process to produce fine and low soda α-alumina (α-Al 2O 3) from a commercial grade aluminium trihydroxide (gibbsite, Al(OH) 3) produced by KC Corporation Ltd was developed. There are two options for this process with the first one producing low soda α-alumina (< 0.05% Na 2O) having a mean particle size of 50 μm. The second option yields a fine product with a mean size of less than 10 μm. In the first option, a plant aluminium trihydroxide containing 0.20% Na 2O was first fluidized with nitrogen at 400–600 °C to yield an amorphous activated alumina. This intermediate product was then treated with acetic or oxalic acid, washed with water and heated to 1200 °C to form calcined α-alumina, having a Na 2O content of less than 0.05%. A 20 min leaching using 0.2 M acetic or oxalic acid could yield an alumina product containing 0.04% Na 2O. In the second option, a new technique for the preparation of fine and low soda α-alumina was evaluated using an attrition mill working also as a leaching vessel at 80 °C. Fine (< 10 μm in mean particle size) and low soda (< 0.04% Na 2O) alumina was produced by a 20 min leaching step with 0.2 M acetic acid and concurrent attrition milling.