Low-temperature smelting process of a bismuth-molybdenum ore

In view of shortcomings in current bismuth-molybdenum ores' floating and smelting technologies, such as complex operation in ore-dressing, large consumption of floating reagents and incomplete separation of bismuth and molybdenum, a low-temperature smelting on bismuth-molybdenum ores is proposed so that the crude bismuth is produced after low-temperature smelting, and molybdenum comes into the solution in form of molybdate. Then molybdenum trioxide can be recycled which is produced by hydrothermal method. On the basis of thermodynamic analysis, effects of molten salt composition, salt amount, smelting temperature, reaction composition and excessive multiples of active carbon on the molten salt smelting of bismuth-molybdenum ores are investigated. The optimum conditions is determined as follows: w(NaCl) /w (NaCl+Na₂CO₃)=20 %, smelting temperature 850 ℃, w(NaCl+Na₂CO₃) /w(bismuth-molybdenum ores)=2, reaction time 1 h, w(activated carbon) /w(theory)=2. Two comprehensive tests under above-mentioned optimum conditions are conducted to find out that the direct recovery rate of bismuth is 98.12 % and 96.59 %, and the average grade of crude bismuth is 96.62 % and 98.87 %.