铋粉低温氧化制备三氧化二铋的基础理论及工艺研究

对铋粉氧化成Bi2O3的过程进行了热力学分析,结果表明,在300～1 600 K范围内氧化反应在热力学上是可行的。采用DSC-TGA热分析方法研究了铋粉低温氧化过程的动力学,发现铋粉低温氧化过程符合未反应收缩核模型。氧化初期为化学反应控制,末期则为固体产物层内扩散控制,表观活化能为55.19 kJ/mol。在理论分析及实验室工艺研究的基础上,进行了半工业试验,金属铋的氧化率接近100%,可直接制备出电子级氧化铋。

Theoretical and Technical Studies on Bismuth Trioxide Preparation by Low-temperature Oxidation Method

A thermodynamic analysis is made on the oxidation of bismuth meal into Bi2O3.The results show that bismuth oxidation is feasible in the range of 300~1 600 K.The kinetics of low-temperature oxidation bismuth has been studied with DSC-TGA thermal method.It is demonstrated that the process of low-temperature oxidation of bismuth meal is in line with the unreacted shrinking core model.During the early period,the oxidation rate is controlled by chemical reaction,but by the diffusion of oxygen molecule in the solid product layer during the final period.The apparent activation energy is 55.19 kJ/mol.On the basis of theoretical analyses and laboratory investigation,pilot tests are carried out.The oxidation ratio of bismuth is approaching to 100%,indicating that electronic grade bismuth trioxide can be obtained directly.