CATHODE CONDITIONING IN MOLTEN SALT ELECTROWINNING OF MAGNESIUM METAL FROM M&lz

I t has been recognised that a major factor which affects the current efficiency in the commercial electrolytic cells for magnesium is the wettability of the cathode surface with respect to magnesium and the ability of the metal deposited to grow into a considerable size on cathode surface before getting released from it. Factors affecting these and studies to improve the wettability have already been reported [I]. However, most of these are related to the composition of the mixture of electrolyte used in each case and conditions have to be optimised for each electrolytic system which is employed for commercial scale cells. The quaternary system of NaCIKCI-BaC12 -MgCI2 has been adopted in the electrolytic cells developed at CECRI for several reasons described elsewhere L2.31. The possibilites of improving cathode conditioning in such systems by marginal adjustments of electrolyte composition, cathode material and the use of addition agents were studied in laboratory scale and the results are reported.