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Risoluzione schermo: 640 x 480 800 x 600 1024 x 768 1280 x 1024 Nome utente: Password: Formato: Basic  Help  Richiesta  Formato: Tipo di Carattere Andale Mono Arial Arial Black Book Antiqua Century Gothic Comic Sans MS Courier New Georgia Impact Lucida Console Script MT Bold Stencil Tahoma Times New Roman Trebuchet MS Verdana   Dimensione del Carattere 1 2 3 4 5 6   Colore del Carattere Nero Rosso Giallo Rosa Verde Arancione Viola Blu Beige Marrone Verde Bosco Blu scuro Marrone scuro Verde chiaro Messaggio: HTML non è attivo Il codice su forum è attivo Faccine [quote][i]Originariamente inviato da SAKURAJUN[/i] [br]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. [/quote]   Seleziona qui per inserire la tua firma.