A Study On The Mechanical Activation And Atmospheric Pressure Acidic Oxidative Leaching Of Molybdenite

With the development of modern society and industry,the application of molybdenum and its compounds has been continued to broaden,which promoted the rapid development of molybdenum smelting and extracting technology.Molybdenite is one of the most important molybdenum raw materials,because of the environmental pollution and other issues of traditional smelting methods,the hydrometallurgical processes get more and more attention.In this study,the oxidative leaching processes of molybdenite in atmospheric pressure and acidic system were explored,three leaching systems were used to investigate different reaction tempreatures,different oxidant concentrations,and different pulp densities to the effect on the extraction of molybdenitein in Fe2(SO4)3/H2SO4 solution,H2O2/H2SO4 solution and HNO3 solution.The oxidative reaction mechanism of molybdnite in three different solutions has been studied using electrochemistry method and analysis.The effect of mechanical activation pretreatment on the properties and oxidation leaching of molybdenite was studied,and the oxidative reaction mechanism of molybdenite after mechanical activation was investigated.The optimum conditions for the leaching of molybdenite without mechanical activation treatment in three different oxidative solutions have been investigated.Compared three leaching solutions,under optimized leaching conditions,the extraction of molybdenum in Fe2(SO4)3/H2SO4 solution was 6%,the extraction of molybdenum in H2O2/H2SO4 solution was 92%,the extraction of molybdenum in HNO3 solution was 78%,respectively.The main components of the leaching residue were unreacted molybdenum disulfide and silicaElectrochemical testing methods were used to explore the leaching mechanism of molybdenite at atmospheric pressure and acidic oxidative solutions.The results show that the main reason of the low extraction of molybdenite was due to the high redox potential and low reactive activity of molybdenite itself.Adding oxidant(Fe2(SO4)3,H2O2,HNO3)can enhance the oxidation leaching reduction potential,so as to improve the extraction of molybdenite.The mechanical activation method was used to pretreat molybdenite.Changes in the properties of molybdenite before and after mechanical activation treatment were investigated using particle size analysis,X-ray diffraction analysis,morphology observation and DSC-TGA analysis.The conclusion indicated that the size of molybdenite decreases and reactivity increases after treatment.Meanwhile,the surface of molybdenite became more smooth during the ball milling process,which might not benefit the occurrence of the leaching process The leaching experiments results showed that the extraction of mechanical activated pretreatment molybdenite in H2O2/H2SO4 solution reached 95%,and the extraction in Fe2(SO4)3/H2SO4 solution were 25%,the extraction reached 88%in HNO3 solution.Elechrochemistry experiments show that the main reasons of those extraction increases was the decrease of particle size and the enhancement of reaction activity.