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

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 Na_2TiO_3, then the resultant Na_2TiO_3 reacts with 3CaO·Al_2O_3·6H_2O resulting from the reaction of CaO with sodium aluminate solution to produce CaO·2TiO_2·H_2O which eventually converts into CaTiO_3. Higher temperature, concentration of free Na_2O_k (the caustic soda uncombined with aluminate anions in the form of Na_2O) and molar ratio of CaO to TiO_2 are favorable to the conversion of CaO·2TiO_2·H_2O to CaTiO_3. 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.