2003 Volume 44 Issue 4 Pages 546-551
Electrorefining of Mg has been investigated in a molten salt system, and the electrolysis conditions for the effective purification have been discussed. A purified mixture of MgCl2–NaCl–CaCl2 was used as an electrolytic bath. Magnesium metal was dissolved anodically by potentiostatic electrolysis, and purified Mg was electrodeposited at the cathode. A certain degree of cathodic overpotential was required for the effective electrodeposition of Mg metal, while large anodic overpotential directly caused the deterioration in the purity of Mg electrodeposit; it was necessary for the anodic overpotential to be less than 1.0 V for good purification. In addition to the electrode potentials, some factors affected the electrorefining of Mg metal. Under the suitable electrolysis condition, the Fe content in the Mg electrodeposit was less than 10 ppm. A couple of subjects on recycling Mg metal and its alloys have been also studied: purification of Mg alloy by an electrorefining technique and distinction of Mg alloys. It was shown that pure Mg metal was electrodeposited at the cathode by the electrorefining of Mg alloy. X-ray fluorescence analysis was applied to distinction of Mg alloys, and the measuring conditions were discussed. It was concluded that the electrorefining process and X-ray fluorescence analysis were usable for the recycling of Mg metal and alloys.