Molybdenum extraction from molysulfide

Two different extraction processes were used to extract molybdenum metal from technical grade molysulfide. The first one involved two steps: open-aluminothermic reduction of molysulfide in presence of potassium chlorate as a thermal booster for obtaining massive molybdenum, and its conversion to high purity molybdenum metal by fused-salt electrore-fining in a KCl-K₃MoCl₆ electrolyte. The second approach aimed at direct recovery of molybdenum from molysulfide-carbon anodes by fused-salt electrolysis again in the KC1-K₃MoCl₆ electrolyte. In the electrorefining of the thermit metal, a metal recovery of 85 pct and an average current efficiency of 70 pct were achieved at 0.6 to 0.75 V using a cathode current density of 7499 A/m² (675 amp/f²) to 8332 A/m² (750 amp/f²), a bath temperature of 1173 K (900°C) and an electrolyte with 7.5 pct molybdenum content. With the same electrolyte and under almost similar conditions, electrolysis with molysulfide carbon anodes at a cathode current density of 14,998 A/m² (1350 amp/f²) to 15,554 A/m² (1400 amp/f²) gave a metal recovery of 82 pct, at an average current efficiency of 50 pct. Both the routes yielded molybdenum of comparable purity. The paper presents a part of the M.Sc. (Tech.) thesis submitted by T. K. Mukherjee to the University of Bombay (India).