熔盐电解法制备Al-Li合金工艺研究

Study on the Technology of Al-Li Compositian with Melten Salt Electrolytic Method

本文利用I-V曲线法测定了锂和钠离子在二元混合熔盐体系(KCl-LiCl、NaCl-KCl)中的析出电位,测出Li+和Na+在液态Al电极上的析出电位之差为+0.27V(ELi-ENa),为利用熔盐电解法制备低钠高纯Al-Li合金提供了理论依据.并在此基础之上对利用液态Al阴极电解制备Al-Li合金的工艺进行了研究探讨,提出使用新的熔盐体系KCl-LiCl-LiF,采用电流密度为1A/cm2,温度为720℃,电解时间70min左右时,电效可达到76%.所制备出的Al-Li合金成分均匀,无偏析现象.

Deposition potentials of Li+ and Na+ on liquid Al cathode has been.measured by potential sweep voltammetry in melts of LiCl-KCl and KCl-NaCl.The deposition potential difference between Li+ and Na+ on Al from the experimental results is +0.27 V at 700 ℃,and +0.25 V at 720 ℃.As a result,Li+ can deposit before Na+ in the presence of sodium ion.This is the theoretical basis for the preparation of high purity Al-Li alloy by electrolysis on Al.And electrolysis conditions are determined by the experimental results:KCl-LiCl(1∶1mol) +8% (w.t) LiF are employed as electrolyte.Electrolyzing temperature is 720 ℃.Current density is 1 A/cm2.The electrolysis process lasts about 70 minutes.And under these conditions,the electronic current efficiency can get to 76%.