The Research And Development Of Removing Coal From Fly Ash By Electrical Separation

The largest obstacle of the fly ash utilizations is the high carbon content. The cost of removing carbon from fly ash by electrical separation is low and fly ash-rich tailings can directly used. This technology shows itself the high efficiency and can gain more pure carbon products than other techniques, therefore it is the most promising means.The design of electrostatic separator is based on the electrical mechanism of mineral. The triboelectrification experiment had been conducted among 10 types of materials and the sequence of triboelectrification of them was PK Zn Al Fe C Mn Cu SiC Ag fly ash. Mn Cu SiC Ag. The paper confirmed that coke and fly ash will characterize the properties of oppositely charged after frictional contact with Mn Cu SiC Ag.Pneumatic conveying electrification for powder conquers the powder adhesion problem which existents in vibrant friction and roller couple friction. The coke and fly ash characterize same electronegative after rubbed with Mn, Cu SiC Ag piping by the mode of pneumatic conveying and they will be the oppositely charged only by rubbed with the materials of M, the fly ash will hold positive charge and the carbon will hold negative charge.The factors of influencing the electrostatic charge on the fly ash such as the relative humidity, gas flow rate, pipeline form and length, the solids-gas ratio were explored.The particles regardless of conductor or non-conductor will show the same electric polarity with the corona charge , and the quantity of electricity will increase if the distance of electrodes decreases and the stayes time increase. The residual charge of non-conductor grain is more than the conductor grain.The result of experiments shows, the particles regardless of non-conductor or conductor can characterize the same polarity with the electrode plate which the particle contacted tlirough the inducted conduction charged. The charge of the particles will increase along with the intensity of electric field, so does the critical particle size of the floating particles.