熔盐电解氧化镁生产铜镁合金  

Production of Cu-Mg Alloy from MgO by Molten Salt Electrolysis

作　　者：杨若凡 雷云涛 吕江江 徐文华 孙丰龙 何利华 赵中伟 YANG Ruo-fan;LEI Yun-tao;LYU Jiang-jiang;XU Wen-hua;SUN Feng-long;HE Li-hua;ZHAO Zhong-wei(School of Metallurgy and Environment,Central South University,Changsha 410083,China)

机构地区：[1]中南大学冶金与环境学院,湖南长沙410083

出　　处：《稀有金属与硬质合金》2025年第2期41-47,共7页Rare Metals and Cemented Carbides

基　　金：国家重点研发计划青年科学家项目(2022YFC2906200)。

摘　　要：在传统熔盐电解法制备金属镁及其合金过程中,使用无水MgCl_(2)作为电解原料面临脱水成本高和腐蚀性氯气产生的问题,而直接使用MgO作为电解原料一直是镁冶金领域的追求。本文通过构建“铜阴极|MgF_(2)-LiF-MgO熔盐|石墨阳极”体系实现了铜镁合金的熔盐电解法直接制备,并系统研究了熔盐体系中离子的电化学行为和MgO在熔盐中的沉降行为。结果表明:采用熔盐电解法制备铜镁合金时,槽电压应控制在1.5~4.5 V,Mg^(2+)在Cu阴极上发生了欠电势沉积,O^(2-)优先于F^(-)在石墨电极上氧化;MgO的低溶解度使电解后的熔盐呈现出分层分布状态,即底部MgO沉降层、中部MgO悬浮扩散层和上部MgO贫化层;MgO贫化容易导致电流强度的衰减或阳极效应的发生。使用Cu为阴极,在2.5 V恒压电解11 A·h后制得Mg质量分数为19.98%的铜镁合金,电流效率为96.67%,合金产物主要由Cu_(2)Mg相组成,并含有少量的CuMg_(2)相。During the preparation of magnesium metal and its alloys by traditional molten salt electrolysis,the use of anhydrous MgCl_(2) as the electrolytic raw material faces the problems of high dehydration cost and the generation of corrosive chlorine gas,while the direct use of MgO as the electrolytic raw material has been pursued in the field of magnesium metallurgy.Therefore,the system of Cu cathode|MgF_(2)-LiF-MgO molten salt|graphite anode was established to realize the direct preparation of Cu-Mg alloys by molten salt electrolysis,and the electrochemical behaviors of the ions in the molten salt system and the settling beha-vior of MgO in the molten salt were systematically investigated.The results show that during preparing Cu-Mg alloy by the molten salt electrolysis method,the cell voltage should be controlled within 1.5~4.5 V.Underpotential deposition of Mg^(2+)occurs on the Cu cathode and O^(2-)is preferentially oxidized over F^(-)on the graphite electrode.The low solubility of MgO causes the molten salt after electrolysis to exhibit a stratified distribution state,namely,the bottom MgO settling layer,the middle MgO suspension diffusion layer,and the upper MgO-depleted layer.The depletion of MgO is likely to lead to the attenuation of the current intensity or the occurrence of an anode effect.Using Cu as the cathode,a Cu-Mg alloy with a Mg mass fraction of 19.98%is obtained after constant voltage electrolysis at 2.5 V for 11 A·h,and the current efficiency is 96.67%.The alloy product is mainly composed of Cu_(2)Mg phase and contains a small amount of CuMg_(2) phase.

关 键 词：氟化物熔盐 电解 氧化镁 铜镁合金 电化学行为 槽电压 沉降 

分 类 号：TG132.32[一般工业技术—材料科学与工程]