THERMOCHEMISTRY AND MECHANISM ON THE PROCESS OF PREP ARING POWDER OF Bi2O3 USING MELT-ATOMIZING-COMBUSTION METHOD
(1.Department of Applied Physics & Thermoenergy Engineering; Department of Materials Science and Engineering;
2.Central South University of Technology; Changsha 410083)
2.Central South University of Technology; Changsha 410083)
Abstract: Based on the experimental results concerning preparing nanometer powder of pure Bi2O3 using the melt atomizing combustion method, the thermochemistry and reaction mechanism of the process of melt atomizing combustion were studied. The results showed that, first, the specific heat capacity of gaseous Bi2O3 at temperature higher than 1 097 K is 105.324 J·mol-1 ·K-1 and its latent heat of evaporation at 2 163 K is 276.896 kJ·mol-1 ; second, the cause for obtaining small powder size and high powder purity is that the processes of preparing powder could proceed upon a model as “atomization — vaporization — combustion — coacervation”, finally , reasonable process parameters of preparing powder of pure Bi2O3 should be melt temperature 900～1 000 ℃, mole ratio of excess oxygen 2～2.5, and cooling intensity of reactor 80～100 kW.
Key words: bismuth trioxide nanometer powder atomizing combustion thermochemistry