熔盐电解法连续生产铝锂中间合金

Continuous Production of Al-Li Master Alloys by Molten Salt Electrolysis

在LiCl-LiF体系的电解槽中，以石墨作为阳极，铝液作为阴极，分别以LiCl和Li2CO3为原料连续电解生产铝锂中间合金，采用熔盐电解监控仪测量电解过程中的工艺参数，重点研究了反电动势、电流效率及合金浓度的变化．结果表明，反电动势随电流密度增加而逐渐增大；加入质量分数2％的Li2CO3可使反电动势降低0．8V，通过控制电位法测得加料周期为30-40min；电解LiCl的电流效率高于电解Li2CO3，最高电流效率可达66．1％；最终在680℃，300A电流条件下，连续电解48h，出炉10次，共制得了平均锂质量分数为6．73％的铝锂合金16kg．

Al-Li master alloys were prepared by continuous electrolysis with either LiCl or Li2CO3 as raw material, where the graphite was used as anode and liquid aluminum as cathode in an electrolytic cell with the LiCl-LiF mixture as electrolyte. The technological parameters in electrolysis process were measured by testing device of molten salt electrolysis, including back EMF, current efficiency and alloy concentration, which were all studied in detail. The results showed that the back EMF increases with current density and decreases by 0.8 V if adding 2wt % Li2CO3. Measured by the method of electric potential control, the feeding period is 30--40 min. The current efficiency in electrolysis process for LiCl is higher than that for Li2CO3, and the highest current efficiency can be up to 66.1%. The gross output of 16 kg Al-Li alloys in which the average lithium content is 6.73% were thus produced 10 times at 680 ℃ and 300 A by continuous electrolysis for 48 h.