Effects of Sodium Tetraborate as an Additive on the Reaction of α-Alumina with Sodium Carbonate

Article abstract of DOI:10.1246/bcsj.53.1600

Effects of sodium tetraborate as an additive in the reaction of α-alumina with molten sodium carbonate have been studied mainly in a N2 atmosphere.Addition of sodium tetraborate accelerates the reaction, the α-alumina reacted increasing from 31.7percent to 99.3percent by addition of sodium tetraborate corresponding to the initial B2O3/Na2O molar ratio of only 1/15 under the other same conditions.By means of the Jander equation the activation energy was found to be 53 kcal/mol for the α-Al2O3-Na2CO3-Na2B4O7 system, which was lower by 10 kcal/mol than that for the α-Al2O3-Na2CO3 system.X-Ray diffraction and thermal data were analyzed in relation to the phase equilibrium of the melt.