Research On Coal Slime Flotation Compound Collector Based On Methyl Oleate

Flotation is one of the effective methods to treat the fine coal separation,and the collector is the key to determine the flotation effect.Coal preparation plant commonly use nonpolar hydrocarbons such as kerosene,diesel oil as collector,but its collecting ability is weak,poor adaptability for coal,especially for low rank coal,kerosene or diesel almost no flotation ability,even if can get ideal separation effect,the reagent consumption,lead to cost increase,the economical efficiency.The research group obtained through previous studies that methyl oleate is a kind of highly efficient coal slime flotation collector.Under the same dosage of agent,the yield of cleaned coal and the recovery of combustible body obtained by methyl oleate are much higher than that of kerosene.This study selected methyl oleate as the basic agent,screening of different HLB value of surfactant AEO-3,AEO-7,OP-4,OP-10,Span 80 and Tween 80 and kerosene as additives and methyl oleate immiscible mixture respectively binary immiscible collector,ternary immiscible collector and microemulsion collector,respectively using kerosene,methyl oleate and compound collector,was carried out on five kinds of coal flotation test,comparing medicament flotation effect and adaptability to coal of kerosene,methyl oleate and compound,In order to get the better collecting performance and higher adaptability than methyl oleate.Using laser particle size analyzer,determination of trace heat meter,infrared spectrometer,to get the dispersed particle size in water,wetting heat,agents and the change of oxygen containing functional groups before and after adsorption,in addition,the frontier orbital energy gap of kerosene(dodecanoic molecules instead of)and methyl oleate molecules and their adsorption energy with coal molecules were calculated by quantum chemical method,the mechanism of the collector action was analyzed based on the test and calculation results.The oxygen content of the five kinds of coal samples is respectively Tunlan coal,Xiegou 13# coal,Xiegou 8# coal,Majialiang coal and Hulusu coal.The oxygen content of the five kinds of coal is successively Tunlan coal < Xiegou 13# coal < Xiegou 8# coal < Hulusu coal < Majialiang coal.The higher the oxygen content of the coal,the more oxygen-containing functional groups on the surface of the coal,and the more difficult the flotation.With the same dosage,for Tunlan coal,Majialiang coal,Xiegou 13# coal and Xiegou 8# coal,the yield of cleaned coal and the recovery rate of combustible body of methyl oleate are higher than that of kerosene,and the dosage of saving agent can reach up to 50%.For Hulusu coal,methyl oleate can improve the flotation effect of coal under the appropriate reagent.Through nonlinear regression,the recovery rate of the combustible body has an exponential relationship with the content of oxygen and nitrogen,and has a negative correlation with the content of oxygen and a positive correlation with the content of nitrogen.When methyl oleate is mixed with kerosene,In a certain proportion,its flotation effect is better than that of single agent.A higher proportion of methyl oleate is needed for Tunlan coal to achieve the best flotation effect,while a smaller proportion is needed for coal with higher oxygen content.Kerosene has enhanced hydrophobic effect,methyl oleate has enhanced hydrophobic and cover the surface of coal oxygen-containing functional groups.Through the nonlinear regression,the synergistic quantitative expression of the mixture of methyl oleate and kerosene is given,which shows that the mixture of methyl oleate and kerosene has synergistic promoting effect,and further improves the collection performance and adaptability to coal.When methyl oleate is mixed with surfactant,the floatation effect is not obviously improved,and the addition of water-soluble surfactant is almost always a negative effect.Ternary miscible collector is a mixture of methyl oleate,kerosene and AEO-3,which shows high collecting capacity for all kinds of coal.Based on the micro emulsion collector configured by methyl oleate,for Tunlan coal,with the same dosage of agent,the rate of cleaned coal and the recovery of combustible body of the micro emulsion agent are the same as that of methyl oleate.For Majialiang coal,Xiegou 13# and Xiegou 8# and Hulusu coal,the clean coal yield and the recovery of combustible of microemulsion collector are higher than that of methyl oleate,and the adaptability to coal is not high.The results of quantum chemical calculation show that the frontier orbital energy gap and adsorption energy are closely related to the collector performance,which can be used as a criterion to judge the collector performance.The frontier orbital energy gap of methyl oleate is lower and its adsorption energy with coal is higher.The results show that methyl oleate has better adsorption property than kerosene and is more easily adsorbed on the surface of coal.Laser particle size analysis shows that the dispersion particle size of the collector in the pulp is closely related to its collection capacity,and the smaller size in the pulp,the better the flotation effect.The particle size of binary collectors mixed with methyl oleate and kerosene is smaller than that of its single agent.The ternary agents mixed with methyl oleate,kerosene and AEO-3 have the smallest dispersion particle size,the best dispersion and the highest collection capacity in water.The wetting heat test results show that the wetting heat of the agent on the coal surface is closely related to its collecting performance.For different types of coal,the adsorption heat of the ternary agent is always higher than that of kerosene and methyl oleate,indicating that the agent has a stronger adsorption on the coal surface and is more likely to react with the coal,thus improving the flotation effect.The results of infrared test show that,for the coal with high oxygen content,the ternary agent can cover the oxygen-containing functional groups on the surface of the coal,make the surface of the coal more hydrophobic,and improve the flotation effect of the coal.In a word,methyl oleate is a kind of highly effective coal slime flotation collector.The flotation effect of binary reagents of methyl oleate and kerosene is better than that of single reagent.The ternary miscible agent composed of methyl oleate,kerosene and AEO-3 has the strongest collecting capacity and the widest adaptability to coal.This provides a new and efficient collector for the coal preparation plant to improve the floatation concentrate yield and reduce the chemical consumption.