Molybdenum recovery ratecanbeover 95％in the treatment of molybdeniteby oxygenpressure and water leaching process.Subsequently,ammonia leachingofoxygen pressure and water leaching residue will lead to the presence of some insoluble molybdate in the ammonia leaching residue,which decrease the recovery of molybdenum.Oxygen pressure and water leaching residue of molybdenum concentrate as raw material with NaOH and Na2CO3 as leaching agents,the effects of leaching agent dosage,temperature,liquid-solid ratio,and leaching time on molybdenum leaching rate were investigated in this paper.The chemical composition analysis of oxygen pressure and water leaching residue and alkaline leaching residue were analysed to reveal the mechanism of alkaline leaching of oxygen pressure and water leaching residue.Results show thatthe oxygen pressure and water leaching residue contains CaMoO4,which cannot be effectively leached by NaOH.In case of using Na2CO3 as leaching agent,spontaneous decomposition of CaMoO4 occurs at temperature above 20℃,and the higher the temperatureis,the easier the decomposition is.The optimum conditions for using Na2CO3 as leaching agent are temperature of 90℃,Na2CO3consumption coefficient of 1.2,liquid-solid ratio of 4:1,time of 90 minutes,and stirring speed of 400 rpm,in which,the molybdenum leaching rate can reach 97.15％.Under the optimum conditions for using NaOHas leaching agent,themolybdenum leaching rateis 93.98％.Results indicatethat the leaching rate of Mo canbe effectively increased by usingNa2CO3 as leaching agent.
molybdenum concentrateoxygen pressure and water leaching residueNaOH leachingNa2CO3 leachingCaMoO4 decompositionthermodynamic analysis
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