The Study Of Modification Of Diatomite Filter Aid Fine Lignite Dehydration

With the tension of the global energy demand and the development of green economy demands,more and more people began to pay attention to the efficient use of coal resources,especially the technology research of use of low-level lignite became a focus and hot spot,but the high content of water of the lignite coal,which directly increased the transportation cost,even influenced the normal operation of production device,and reduced the coal to these as the raw power generation or the economy of the Efficient use.For the viscous slurry,low filter speed and high moisture of fine-grained lignite,to develop a reasonable set of fine-grained lignite dewatering,seeking an effectively fine-grained lignite vacuum dewatering technology method is a Premise of effective use of lignite,having an important practical significance.The raw laterial of this thesis was derived from the Zhalainuoer North mines in Mongolia.On the basis of the determination of fine lignite surface properties and pore structure,Clear the effect of different concentrations of fine lignite eoal slurry dewatering.Use diatomaceous earth filter aid to help fine lignite dehydration,and using FeCl3,H2O2 and KMnO4 three kinds of modifiers modified diatomite,study different modifiers on modified diatomite filter aid effect.Diatomite modified conditions change,examine the impact of changes in pH values modified diatomite filter aid effectiveness,to identify the impact of lignite dehydration modified diatomite law,drawn suitable lignite dehydration diatomite modified conditions.And the use of scanning electron microscopy,contact angle,infrared,laser particle size analysis by means of the modified diatomite filter aid after dewatering lignite coal samples for testing to characterize,were discussed from the mechanism.The following conclusions were drawn:1.In the vacuum filtration test of coal slurry,the total moisture of cake increased with the increasing of concentration of coal slurry,but totally had removal effect which is not obvious.When the concentration of coal slurry is 160g/L,and the total moisture of cake is 41.63%.2.Using of grapHite-the iron electrode,investigated modified product type,dosage modified material impact on the results of the modified diatomite.In FeCl3 modified diatomite,H2O2 and KMnO4 modified diatomite modified diatomite three modifier,FeC13 modified diatomite filter aid effectiveness lignite best.Meanwhile,in a certain range,cake moisture increases the overall amount of modifier showing decreasing trend,pulp filtration rate tended to increase.3.Fe3+ modified diatomaceous earth filter aid to improve its effect on lignite.When the concentration of diatomite 5%,the dosage is 3ml,compared with the previous diatomite modified lignite cake moisture content is reduced to about 3 percent,pulp filtration rate increased by nearly 50%.4.Changing the pH conditions can affect the Fe3+ modification effect of modified diatomite.Under acidic conditions,with the decrease of pH value,lignite cake full of water to reduce the water after the first showing an increasing trend,pulp filtration rate increase after the first showing decreased;under alkaline conditions,around the time when pH=8 cake moisture content of lignite to reduce short-term,transient increases in pulp filtration rate;then with increasing pH value of water as a whole cake full of water showing an increasing trend,showing a slurry filtration rate decreased.Comprehensive experimental conditions consldered in acidic conditions pH=5,Fe3+ modified diatomite filter aid effectiveness lignite best.5.Using appropriate means to characterize the modified diatomite filter aid after dewatering coal samples for testing.Analyzed by FTIR,contact angle measurement of coal particles,the particle size measured by a laser,SEM characterization of the surface structure,Fe3+ is supported on the surface of diatomite,celite improve the internal pore structure,which increases the surface area and the pore radius change diatomite surface electrical resistance,diatomaceous earth filter aid to improve the performance of lignite.