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Preparation of alumina from heated kaolin leached by citric acid with AACH as an intermediate / Zhanglong Yu in Industrial & engineering chemistry research, Vol. 50 N° 14 (Juillet 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 14 (Juillet 2011) . - pp. 8524–8528 Titre : Preparation of alumina from heated kaolin leached by citric acid with AACH as an intermediate Type de document : texte imprimé Auteurs : Zhanglong Yu, Auteur ; Yongmei Chen, Auteur ; Zhixia Shi, Auteur Année de publication : 2011 Article en page(s) : pp. 8524–8528 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Preparation  Heated  kaolin Résumé : Because the supply of bauxite ores in many countries is becoming deficient, a process of preparing alumina from an alternative resource, namely, kaolin, is proposed in this work. First, kaolin was heated at 600 °C for 2 h before being leached with 1 M citric acid solution, about 75% of the Al in kaolin entered the leachate as aluminum citrate (AlCit) solution. Then, about 50% of the Al(III) in the leachate could be precipitated as ammonium aluminum carbonate hydroxide (AACH) by addition of NH4HCO3 at pH 9.00 ± 0.50. The morphology of AACH characterized by SEM and TEM was spherical particles composed of many nanorods with sizes of about 500 × 25 nm. Finally, mesoporous γ-Al2O3 was obtained by roasting AACH at 700 °C. The Fe and Na contents in the obtained γ-Al2O3 product determined by XRD and ICP-AES were 2 and 0.1 ppm, respectively. The obtained γ-Al2O3 had a morphology similar to that of AACH, and its BET surface area was as high as 235.2 m2/g. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24346893 [article] Preparation of alumina from heated kaolin leached by citric acid with AACH as an intermediate [texte imprimé] / Zhanglong Yu, Auteur ; Yongmei Chen, Auteur ; Zhixia Shi, Auteur . - 2011 . - pp. 8524–8528. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 14 (Juillet 2011) . - pp. 8524–8528 Mots-clés : Preparation  Heated  kaolin Résumé : Because the supply of bauxite ores in many countries is becoming deficient, a process of preparing alumina from an alternative resource, namely, kaolin, is proposed in this work. First, kaolin was heated at 600 °C for 2 h before being leached with 1 M citric acid solution, about 75% of the Al in kaolin entered the leachate as aluminum citrate (AlCit) solution. Then, about 50% of the Al(III) in the leachate could be precipitated as ammonium aluminum carbonate hydroxide (AACH) by addition of NH4HCO3 at pH 9.00 ± 0.50. The morphology of AACH characterized by SEM and TEM was spherical particles composed of many nanorods with sizes of about 500 × 25 nm. Finally, mesoporous γ-Al2O3 was obtained by roasting AACH at 700 °C. The Fe and Na contents in the obtained γ-Al2O3 product determined by XRD and ICP-AES were 2 and 0.1 ppm, respectively. The obtained γ-Al2O3 had a morphology similar to that of AACH, and its BET surface area was as high as 235.2 m2/g. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24346893