Effect Of Magnetized Reagents On Coal Flotation

As a non-renewable resource,the efficient utilization of coal depends on the effective processing of coal.Flotation is the main method for separating-0.5mm granular slime.Kerosene is widely used in coal processing in China.It is mainly used as flotation collector for slime.In industrial practice,problems such as low recovery rate of clean coal,poor selectivity of reagents and high consumption of reagents often exist,which have a great impact on flotation effect.The content of this paper is mainly based on the study of the flotation efficiency of kerosene and its compound reagent after magnetization treatment for different properties of slime.The magnetic equipment is a self-designed and self-assembled adjustable solenoid magnetic field.Kerosene,kerosene and surfactant are placed in the magnetic field.The field strength at the magnetic field center is regulated by a DC regulated power supply.The changes of the pharmaceutical properties under different magnetic conditions are understood through the tests of apparent viscosity,surface tension and droplet dispersion.The effect of magnetizing agent on different properties of slime was investigated by the indexes of flotation concentrate yield,combustible recovery and flotation perfection.Majialiang coal and Tunlan coal were selected as test coal samples.Among them,Majialiang coal has low metamorphism,high surface oxygen content and poor floatability;Tunlan coal has medium metamorphism,low surface oxygen content and relatively good floatability.The kerosene treated by magnetization has obvious effect on the flotation of Majialiang and Tunlan coals,and the yield of clean coal and the recovery rate of combustible matter have been greatly improved.When the magnetization condition is 30 C,0.3T and 5 min,the flotation upgrading effect of magnetized kerosene on Majialiang slime is the best.The concentrate yield reaches 65.29%,the recovery rate of combustible material is 74.79%,which is 14.29% and 15.64% higher than that of unmagnetized kerosene.For Tunlan coal,the yield of flotation concentrate and the recovery of combustible matter were increased by 3.34% and 5.22% respectively when the suitable magnetization conditions were 30 C,0.1T and 5min,compared with those of unmagnetized kerosene.In kerosene-based compound reagents,after magnetization,the effect of kerosene and ethyl oleate composite reagents on the flotation of coal slime is not obvious,and even has some inhibition effect.After magnetization,the flotation effect of kerosene and AEO-3 and kerosene and Span80 composite reagents tends to increase with the increase of magnetic field intensity at lower reagent dosage.The flotation concentrate yield and combustible recovery of kerosene-span composite reagents increase 3.76% and 5.26% for Majialiang coal,2.99% and 2.66% for Tunlan coal,respectively;and the flotation effect of AEO 3-kerosene on two kinds of coal is improved.They were 5.91%,5.88%,3.31% and 4.56% respectively.The results show that magnetization has a certain effect on the flotation effect of kerosene compound reagent.The results of physicochemical properties test show that the kerosene viscosity first decreases and then increases with the increase of magnetic field intensity,and there exists an optimum condition for the maximum decrease of 6.2%.The mixture of ethyl oleate and kerosene also decreases to a certain extent after magnetization,but the decrease is small.The viscosity of kerosene and span 80,AEO-3 composite agents changes greatly and decreases first.Later increase,similar to kerosene magnetization effect,shows that magnetization treatment can reduce the apparent viscosity of liquid agents to a certain extent.With the increase of magnetic field intensity,the surface tension of kerosene first decreases and then increases,with a decrease of about 0.75%.There is an optimum condition.The change of ethyl oleate is not obvious.The surface tension of kerosene and span 80 and AEO-3 compound agent changes slightly.After magnetization,the dispersity of kerosene in water changed,and kerosene dispersity increased.After magnetization,kerosene,a compound of ethyl oleate,span80,AEO-3 and kerosene,appeared double peaks and multi-peaks,which indicated that its liquid particle size composition changed greatly and its dispersity increased.The decrease of the viscosity and surface tension of the reagent is beneficial to the diffusion of the reagent on the surface of coal particles.The diffusion velocity of magnetized kerosene on coal surface was measured.It was found that the diffusion velocity of kerosene changed greatly after magnetization.Compared with unmagnetized kerosene,the diffusion time of kerosene was about 21 seconds shorter and 37.5% shorter.This indicated that magnetization could accelerate the diffusion speed of kerosene on coal surface and enhance the collection efficiency of kerosene.In a word,magnetic treatment of conventional flotation agents such as kerosene can change the physicochemical properties of agents to a certain extent,and the flotation effect of magnetic agents such as the yield of clean coal and the recovery rate of combustible substances is basically better than that of non-magnetic agents,and the effect of modification is better.This can provide a new idea for coal preparation plant to improve the yield of clean coal and reduce production costs.