论文部分内容阅读
针对铁粉置换沉积海绵铋所得铋粉品位较低的缺点,本工艺采用铁片置换海绵铋,铁片为阳极,石墨为阴极,直流微电流作用,电流密度5×10-3A/cm2,温度40℃,所得海绵状铋粉品位在90%以上。通过置换过程的宏观动力学研究表明,其置换过程符合一级反应速率规律,活化能E a=13.72 kJ/mol,反应速率方程为v=3.2470×c(Bi3+)exp(-13720/RT),置换过程的控制步骤为扩散控制。电化学分析结果显示,微电流作用很好的促进了置换过程,且置换海绵状铋粉品位高,杂质少,尤其铅含量明显降低。
Aiming at the low grade of bismuth powder obtained by replacing bismuth sponge deposited by iron powder, the present invention uses iron plate to replace bismuth sponge, iron plate as anode, graphite as cathode, direct current micro current, current density 5 × 10-3 A / cm2, temperature 40 ℃, resulting sponge bismuth powder grade above 90%. The macroscopic kinetic study of the displacement process shows that the substitution process accords with the first order reaction rate, the activation energy E a = 13.72 kJ / mol and the reaction rate equation v = 3.2470 × c (Bi3 +) exp (-13720 / RT) The control step of the displacement process is diffusion control. The results of electrochemical analysis showed that the micro-current promoted the displacement process well, and replaced the spongy bismuth powder with high grade and less impurities, especially the lead content was obviously decreased.