Preparation Of Oil-in-water Emulsified Diesel Oil And Its Mechanism Of Strengthening Molybdenite Flotation

Molybdenum,as an important non-ferrous metal resource,is an important strategic material for national planning and an important scarce material for industrial development and national defense construction.It has been widely used in many fields.Diesel oil is a common collector for flotation molybdenite,but because of its poor dispersion in ore pulp,it can not meet the needs of social production.In this paper,aiming at the problem of poor dispersity of diesel oil in ore pulp,ultrasonic pretreatment of diesel collector was carried out,and surfactant was added to prepare oil-in-water emulsified diesel oil as molybdenum collector to improve the flotation effect of molybdenite.By means of particle size detection,microscope observation,viscosity test,surface potential detection,contact Angle measurement,Fourier transform infrared spectroscopy detection and EDLVO theoretical calculation,the mechanism of emulsified diesel oil enhancing molybdenite flotation and reagent dispersion was revealed.The ore in this study is polymetallic ore dominated by molybdenum,with molybdenum content of 0.195%.When the-200 mesh in the sample is 60%,the monomer dissociation degree of molybdenite reaches 74.56%,with high dissociation degree and easy to flotation separation.Flotation results show that the ultrasonic pretreatment of diesel oil,oil/water ratio of 1:10,polyoxyethylene laurel ether as emulsifier oil-in-water emulsified diesel oil,can be got the good properties of molybdenite collector,the best preparation conditions as follows: the emulsifier dosage is 1.5% of the total quality of oil,water,ultrasonic power 300 W,ultrasonic time 2 min.Molybdenum concentrate with grade and recovery of 7.71% and 86.72% were obtained by using this collector.Compared with the original diesel collector,molybdenum concentrate grade and recovery were increased by 0.19% and 3.44% respectively.Particle size test,microscope observation and viscosity test show that ultrasonic pretreatment of diesel oil can effectively reduce the size of diesel oil droplet and improve the dispersion effect of diesel oil in ore pulp.After ultrasonic pretreatment(without emulsifier),the average particle size of diesel oil can reach 135.97 nm,but this kind of emulsified diesel oil is easy to stratify and difficult to preserve.After adding emulsifier,the average particle size of emulsified diesel oil can reach 18.87 nm,the dispersing ability can be further improved,and the emulsified diesel oil can be stored for a long time.The dispersity and stability of emulsified diesel oil can be improved significantly even with the addition of trace emulsifier.The results of surface potential and contact Angle measurement show that both diesel and emulsified diesel can act on molybdenite,resulting in reduced polarity of molybdenite and enhanced hydrophobicity,and emulsified diesel has stronger effect.The results of infrared spectrum analysis showed that diesel and emulsified diesel were adsorbed on the surface of molybdenite,and the adsorption mode was physical adsorption.EDLVO theoretical calculation results show that emulsified diesel oil has a low energy surface,which is lower than that of diesel oil and water,showing different amphoteric characteristics from diesel oil.In the whole interaction distance,the total potential energy VT of molybdenite particles under the action of emulsified diesel oil is attraction energy.The total potential energy VT of molybdenite particles under the action of diesel oil changes from negative to positive at the action distance of 40 nm.The addition of diesel oil and emulsified diesel oil can change the total potential energy of molybdenite particles,which is beneficial to the flotation of molybdenite particles,and the strengthening effect of emulsified diesel oil is stronger.The potential energy of diesel oil,emulsified diesel oil and water interface can directly reflect the dispersion properties of diesel oil and emulsified diesel oil in water.The VT curve of total potential energy of diesel oil interaction shows that the dispersion ability of emulsified diesel oil in water is much greater than that of diesel oil.