Abstract: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·Al₂O₃·6H₂O resulting from the reaction of CaO with sodium aluminate solution to produce CaO·2TiO₂·H₂O which eventually converts into CaTiO₃. Higher temperature, concentration of free Na₂O_k (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.

Key words: anatase; hydroxy calcium titanate; calcium titanate; high-pressure digestion; reaction mechanism