| R E V I S I O N E D E L L A D I S C U S S I O N E |
| SAKURAJUN |
Inviata - 06/01/2021 : 06:50:57
Ammonium aluminium carbonate hydroxide NH4Al(OH)2CO3 as an alternative route for alumina preparation: Comparison with the classical boehmite precursor[url=https://www.hslabrasive.com/]hslabrasive[/url]
Ammonium aluminium carbonate hydroxide (AACH) is a promising alternative precursor for preparation of alumina with high purity and original textural properties. In this paper, both boehmite (classical alumina precursor) and AACH were precipitated in a stirred tank reactor with close process parameters. Preparation protocols were thus compared. Main differences between both protocols were pointed out (reactant molar ratio influence, alumina concentration, filtration/washing step). This study helps for the choice of the appropriate preparation route for alumina precursor synthesis. As-synthesized boehmite and AACH precursors were then calcined between 500 °C and 1000 °C. The textural properties of the corresponding aluminas were characterized. At 500 °C, AACH-derived alumina revealed to be particularly porous, with larger mean pore diameter (ca. 29 nm) than boehmite-derived alumina (ca. 6 nm).[url=https://www.hslabrasive.com/products/fused-alumina/brown-fused-alumina.html]fused alumina abrasive[/url] Moreover, AACH-derived alumina exhibited a high surface area. However, a more accurate analysis revealed that this high specific surface area (407 m2·g#8722; 1) is mostly due to microporosity formation during the calcination step. At higher calcination temperature, boehmite and AACH-derived aluminas exhibited different behaviors against sintering. In particular, the latter showed an interesting ability to maintain a constant mean pore diameter, regardless of the calcination temperature. |
|
|
