| This study is to determine the alkali-leaching mechanism by which complex compound by the reaction made between molybdenite (MoS₂) and ferric oxide (Fe₂O₃) in the roasted are when molybdenium trioxide (MoO₃) is formed by the roasting reaction of molybdenite concentrate. The results obtained from this experiment are summarized as follows; 1) The heating reaction analysis shown that the complex compound of iron molybdates (Fe₂O₃·3∼4 MoO₃) is formed by the reaction of molybdenium trioxide and ferric oxide at temperatures of above 500℃. 2) It is shown that at various reaction temperature below 400℃ molybdenium trioxide is almost completely leached by caustic soda irrespective of the mole ratio of two chemical samples used for the experiment, whereas at temperature above 400℃ the leaching rate of molybdenium trioxide decreases except that it varies from 70.77% at a temperature of 900˚at which the mole ratio is 1 to 1 to 84.08% at a temperature of 1000℃. 3) The x-ray diffraction analysis has shown that the complex compound reacted at a temperature of 1000℃ produces a complelex compound with the crystal structure of iron molybdates, and the alkali-leached residues even with 19.0% of molybdenium trioxide, however, contain only α-Fe₂O₃, without showing iron molybdates. 4) The crystalline compound of iron molybdates obtained as a result of heating reaction was leached by using caustic soda, while MoO₃, and Fe₂O₃in the leaching residue was found to contain other compounds unable to be leached by caustic soda. |
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