Novel Technology Of Pressure Leaching Complex Molybdenum Ore

China is rich in molybdenum resources,but the resources has poor endowment and usually associated with nickel,copper,rhenium,vanadium and other valuable elements,e.g.Ni-Mo ore of black shale,molybdenum concentrate with high content of rhenium and copper.These low-grade complex molybdenum ores are not suitable for treatment by the traditional molybdenum metallurgical process?roasting-ammonia leaching?,which has the disadvantages of sulfur dioxide pollution and low recovery of associated metals.Therefore,research and development of environment-friendly processing technologies for low-grade complex molybdenum is of great significance.Pressure leaching,which is known as an enhanced metallurgical technology with short flowsheet,environment-friendliness and high metal recovery,is prospecting in treatment of low-grade ores,polymetallic ores and complex ores.The dissertation systematically studied the pressure leaching process and mechanism of complex molybdenum ores.The main research contents of this dissertation are as follows:?1?The kinetics of pressure oxidation of molybdenum middlings?Shanxi Jinduicheng?was studied,the kinetic model was developed and reaction mechanism of the leaching process was discussed.Results showed that thepressure oxidative leaching process of molybdenite was controlled by interfacial chemical reaction as the leaching rate 1-?1-x?1/3 being linearly related to time;the reaction followed kinetic rules of the unreacted shrinking core model controlled by the interfacial chemical reaction,and the reaction activation energy E is 112.24 kJ·mol^-1.?2?Pressure oxidative leaching behavior and rule of Ni-Mo ore?Hunan Zhangjiajie?was carried out,and an novel method for effective oxidativedecomposition of Ni-Mo ore without additives was invented.The results showed that when the temperature was 150?,oxygen partial pressure was 405.2 KPa,total pressure was 911.7kPa,liquid-solid ratio was 3 L/kg,stirring speed was 500 r/min,no additives was introduced and reaction time was 2h,the average leaching yield and conversion rate of Mo were 41.93%and 98.33%,respectively,simultaneously,the average leaching yield of nickel was 98.46%,realizing the whole hydrometallurgical processing of Ni-Mo ore.?3?Pressure oxidative leaching behavior and rule of complex high-Re molybdenum concentrate?Dexing Copper Mine high-Re molybdenum concentrate?was carried out,and an novel method for comprehensive recovery of Mo and Re under mid-temperature and pressure was invented.The results showed that when the reaction temperature was 180? oxygen partial pressure was 6atm,total pressure was 16atm,liquid-solid ratio was 6 L/Kg,stirring speed was 600 r/min,the addition of active carbon was 5%,and reaction time was 4h,the conversion rate of Mo was 99.17%and the leaching rate of Mo was 16.22%.Compared to traditioanl pressure leaching process of molybdenum concentrate,the process decreases the temperature from 220? to 180?,reduces the pressure from 3.14 MPa to 1.52 MPa,resulting in a mild reaction condition and lower capital cost and operation cost.?4?It was found that adding active carbon can accelerate the leaching of molybdenite,and the galvanic effect model was proposed based on the electrochemical corrosion intensification process nature of pressure oxidation leaching of mixed molybdenite and activated carbon.When molybdenite is contacted with activated carbon particle,the formed original batterycan reduce the corrosion potential of molybdenite.Galvanic effect is enhanced as corrosion current increases and in turn accelerates the oxidative dissolution of anode molybdenite and improves the leaching rate of molybdenum,thereby reducing the reaction temperature and pressure.?5?Solvent extraction of rhenium and molybdenum from the pressure leaching solution of high-Re molybdenum concentrate was carried out and an novel method for solvent extraction of rhenium and molybdenum from high acidic leachate was invented.The results showed that under the conditions of the organic phase composition of 0.5vol.%N235-10vol.%isooctanol-kerosene,phase ratio?O/A?of 1/2,room temperature and mixing time of 1 min,the extraction yield of rhenium reached 97.87%after seven-stage counter-current extraction.The stripping yield of rhenium was nearing 100%after the loaded organic phase was sing-stage stripped by 5%ammonia when the phase ratio O/A was 8 and mixing time was 3min.The extraction yield of molybdenum reached 99.20%after two-stage counter-current extraction when the organic phase composition was 20vol.%N235-5vol.%isooctanol-kerosene,phase ratio?O/A?was 1/2 and mixing time was 2min.The stripping yield molybdenum was 97.79%after three-stage counter-current stripping by 15%ammonia when phase ratio?O/A?was 2 and mixing time was 3min.