Preparation Of Microemulsified Collector Based On Kerosene And Application In Froth Flotation

Flotation is the main method of fine coal preparation,and kerosene is generally used as collector.But most of the coal preparation plants have many problems,such as low recovery of clean coal,bad selectivity and high consumption,which seriously affect the flotation efficiency.So it is necessary to develop efficient collectors of good selectivity and low consumption.In this research,the preparation of microemulsified collector based on kerosene and foaming agent is studied.It's concluded that after more than two hundred times of tests,Span and Tween could become mixed surfactants,which can be formed to get uniform and transparent microemulsion with kerosene,sec-octyl alcohol and water when the ratio is from 26% to 36%,from 36% to 50%,from 9% to 16%,from 5% to 25% respectively according to the surfactant formulating principle.Then pseudo-ternary phase diagram is used to study the phase behavior of microemulsions and it's concluded that the area of microemulsion is biggest and the effect of microemulsion is best when the ratio of surfactant and co-surfactant is 1.5.The particle size of microemulsions are characterized by Nano-ZS90(Malvern)laser particle size analyzer and the average particle size is less than 100 nm,which agrees with the definition of microemulsion.The transmission ratio and absorbance of microemulsions are characterized by visible spectrophotometer and it is concluded that the particle size distribution is inversely proportional to transmission ratio and the smaller the particle size,the larger the transmission ratio is.Then froth flotations are carried out with Majialiang coal of Shuozhou,Tunlan coal of Gujiao and Dayuan coal of Xinzhou coal respectively with kerosene and microemulsions as the collector and then compare the collecting performance.For Tunlan coal of Gujiao,the improved flotation indexes of microemulsion No.1 and No.16 are higher than that of others,which illustrates that microemulsion No.1 and No.16 have better selectivity.For Majialiang coal of Shuozhou,recovery of clean coal and ash content of tailing of microemulsion are significantly higher than that of kerosene,which demonstrate microemulsion has good collecting performance.Microemulsion No.2 and microemulsion No.17 are particularly good collectors for Majialiang coal and kerosene is not ideal collector;For Dayuan coal of Xinzhou,microemulsion No.3,4,11,14,23,25,26 and 30 have good collecting performance.Particle image analyzer MV-E2900 C is used to observe the mixture of which the ratio of microemulsion and kerosene is 2:1 and then take pictures.The results show that the solubilization of microemulsion No.21 in kerosene is best,and kerosene becomes part of the microemulsion.At the same time,the mixture of which the ratio of microemulsion and water is 1:1 is observe by MV-E2900 C.The results show that the kerosene is difficult to disperse and it is in water by the form of drop.And microemulsions,especially microemulsion No.17,disperse in water evenly,which indicates that microemulsion can also disperse in the slurry evenly.Wetting heat tests show that the larger of wetting heat,the higher the recovery of clean coal is;Wetting heat of microemulsions are better than that of kerosene,so the recoveries of clean coal of microemulsions are higher than that of kerosene.Contact angle measurement shows that the contact angles of clean coal and collector have a good negative correlation with the recovery of clean coal,and the big contact angle indicates that it is easy for collector to adsorpt on the surface of coal particles and collectors could improve the hydrophobicity of raw coal surface significantly;Contact angles of microemulsions are smaller than that of kerosene,so the recoveries of clean coal of microemulsions are higher than that of kerosene.In summary,selecting the appropriate microemulsified collectors on different coals can get good flotation effect,which provides a new possibility about increasing the recovery of clean coal,reducing the ash of tailings and decreasing the consumption of collectors for coal preparation plants.