The Kinetic Mechanism Of Producing High Purity Molybdenum Concentrate By Classification-fractional Speed Flotation

The high purity molybdenum concentrate has the excellent characteristics of solid lubricant,leading to the continuous increase of its demand.According to the process flow,high purity molybdenum concentrate can be divided into two categories:chemical synthesis method and physical purification method.But the chemical synthesis and preparation method of high purity molybdenum concentrate has the characteristics of long process flow,high production cost and great pollution.It is necessary to explore a kind of preparation method of high purity molybdenum concentrate which is economical and reasonable,simple process and small pollution.Therefore,this paper attempts to obtain high purity molybdenum concentrate（57 molybdenum concentrate）from the perspective of flotation.However,there are difficulties in purification by flotation method:the grinding particle size is too fine,so that the surface properties of different minerals tend to be the same,and the separation is difficult.In order to solve this key problem,in this paper,Jinduicheng molybdenum crude concentrate as the research object,using classification-fractional speed flotation to produce high quality molybdenum concentrate,and through the classification-fractional speed flotation kinetics and hydrocarbon oil to enhance the fractional flotation effect of molybdenite,study the collaborative mechanism of the process,and obtain ideal research results.The results of classification-fractional speed flotation kinetics showed that the fractional flotation model（including the non-floating part）had the highest fitting degree and simulated the flotation process of coarse molybdenum concentrate of each size.Each particle’s accumulated recovery rate was dominant,providing a theoretical basis for fractional flotation.In addition,in the process of deducing the whole particle size model with the mathematical model of each particle size,it was found that the model derivation results and the test results were quite different.The self-carrier effect was confirmed by the optical microscope and laser particle size analysis.Therefore,based on the carrier effect,the model was modified and the optimization method of the flotation mathematical model was innovatively proposed,which was not affected by the particle size effect.It can provide a theoretical basis for establishing a flotation dynamic model under complex and variable conditions.The process results of classification-fractional speed flotation of high-quality molybdenum concentrate showed that the grade of molybdenum crude concentrate was difficult to be greatly improved by multi rate cleaning stages without classification.However,when the classification-fractional speed cleaning stages were used,the molybdenum concentrate grade could reach 55～56%for six multi rate cleaning stages of-45μm,while the grade of+45μm only reached 45～46%for six multi rate cleaning stages,which needed fine grinding to achieve complete dissociation,to improve the grade of molybdenum concentrate.The high-quality molybdenum concentrate with fine size（-45μm）flotation at separate speeds was as follows:Mo grade was 57.34%,Si O₂grade was 1.59%;The high-quality molybdenum concentrate with coarse-grade（+45μm）regrinding（fineness of 61.31%）and separate flotation showed that Mo grade was58.57%,Si O₂grade was 1.74%.All of them reached the standard of high quality molybdenum concentrate.The mechanism study of hydrocarbon oil enhancing the fractional speed flotation effect of molybdenite showed that with the addition of collector,the improvement range of fine grade（-38μm）was greater than that of-45+38μm.There was competitive adsorption between the coarse and fine grade of chemical diesel oil,which would give priority to strengthen the flotation of fine grade and improve the flotation rate,so as to improve the grade of molybdenum concentrate.The adsorption isothermal Freundlich model had the best fitting degree.Combined with infrared spectrum analysis,it could be seen that diesel oil physically adsorption on the surface of molybdenite,and the adsorption speed was fast.The second-order adsorption kinetics model could more accurately describe the adsorption behavior of diesel oil on molybdenite particles.The intramolecular diffusion kinetics showed that diesel molecules could rapidly diffuse and adsorb on the surface of molybdenite.Therefore,diesel fuel could enhance the fractional speed flotation effect of molybdenite.