Reaction behavior and mechanism of anatase in digestion process of diasporic bauxite

• Published in: Transactions of Nonferrous Metals Society of China Vol. 20; no. 1; pp. 142 - 146
• Main Author: 李小斌 付伟岸 周秋生 刘桂华 彭志宏
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2010; School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China
• Subjects: Al2O3; Aluminum base alloys; Anatase; Bauxite; Bayer process; calcium titanate; Caustic soda; Digestion; high-pressure digestion; hydroxy calcium titanate; reaction mechanism; Sodium hydroxide; Titanium dioxide; 反应机制; 消化过程; 铝土矿; 铝酸钠溶液; 锐钛型; hydroxy calcium titanate; high-pressure digestion; calcium titanate; reaction mechanism; anatase
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(09)60111-4

Based on the study of influence of temperature, digestion time, amount of CaO added and composition of aluminate solution on reaction behavior of pure anatase in high-pressure digestion process of bauxite, reaction mechanism of anatase was preliminarily determined. Anatase first reacts with caustic soda to produce Na2TiO3, then the resultant Na2TiO3 reacts with 3CaO·Al2O3·6H2Oresulting from the reaction of CaO with sodium aluminate solution to produce CaO·2TiO2·H2O which eventually converts into CaTiO3. Higher temperature, concentration of free Na2Ok （the caustic soda uncombined with aluminate anions in the form of Na2O） and molar ratio of CaO to TiO2 are favorable to the conversion of CaO·2TiO2·H2O to CaTiO3. And Al（OH）4^- shows the function of a catalyzer in the reaction of anatase with caustic soda with or without CaO added during the digestion process of diasporic bauxite.