Research On Dense Medium Coal Middlings Separation Of Huaibei Coal Preparation Plant

China is extremely short of scarce coal resource, especially the scarce and lack ofcoking coal. The distribution of scarce coal is extremely uneven. However, there is aserious phenomenon of irrational use of scarce coal, a large amount of middlings ofthese coal have been used as thermal coal, which resulted to great waste. The depthimplementation of clean coal strategy, optimize of product structure and improve ofcoal production, which become to the urgent need to improve the situation of coalenterprises when faced with the continued downturn in the coal market. Theexploitation of scarce coking coal middlings has greatly value. The research of coalmiddlings re-election has great important and far-reaching significance in improvingeconomic efficiency of enterprises and efficient use of energy resources and meetingthe environmental requirements.Selecting the heavy medium coal middlings of Huaibei coal preparation plant asthe research object. The paper was conducted by a moderate dissociation coalcrushing and separated by flotation, centrifugal separation and TBS separator toexplore reasonable re-sorting method of coking coal resources.First of all, the nature of raw coal middlings was analyzed by the screening andfloat-sink test. The results show that the composition of coal particle size is smallerand the content of slime is less, which is extremely difficult to separate. It can not bequalified from directly sorting coal. The cola middlings bears further dissociatepossible to dissociation and extract clean coal. But the coal sample contains largeamounts kaolinite which belongs to clay minerals, which has some influence in thedissociation process of sorting.Through the crushing and dissociation test of the raw coal middlings, the densitycomposition and dissociation of different particle size limit was analysed, the testresults showed that: the finer the granularity broken, the greater the content whichdistributed to high and low density levels, the less the intermediate density levelcontent, the more fully dissociated between coal and minerals, the higher thetheoretical yield of clean coal under the certain ash requirements. When coal iscrushed to less than0.5mm, the cumulative yield of floats around35%, comparedwith8%broken before, increase significantly. Considering facts in terms of energysaving and the follow-up sorting operations and impact on coking properties of suchtests to determine the subsequent sorting of coal samples were crushed to-0.5mm coal sample.The optimum flotation condition was identified by initially orthogonal test.Through the release distributed by flotation tests, the clean coal of ash as12.74%anda yield of5.67%was received, which indicated that the dissociation have certaineffect. However the ash of flotation concentrate was generally high and the yield waslower, which resulted to poor flotation effect. The cause of poor flotation was not thepollution of high ash fine mud through the analysis of flotation products particle size,the insufficient dissociation was the great possibly.The coal middlings was separated by Falcon centrifuge used aqueous as medium.The optimum test condition was determined by the orthogonal test. Using thepre-sorting off the mud and then centrifugation, the clean coal was42.46%yield and13.37%ash content when change the process.The coal sample with crushed to1mm or less was sorted by TBS and predictedby heavy medium cyclone separation. The poor test conditions and less controlparameters and other facts result to the less effective TBS sorting result. Theprediction of heavy medium cyclone separation has not made a qualified fine coalproducts either.Combined with the actual site, the economic benefits of the centrifuge separationprocess with the mud off is significant,as well as the use of slime heavy mediumcyclone separation prediction, which made the clean of less than12%ash. The coalmiddlings was crushed and dissociated to less than0.5mm and then separated bycentrifugal separation or slime heavy media separation.The paper has figure23, table39and reference113.