Experimental Study On Dissociation And Separation Of Middlings

China had abundant coal resources,the total reserves of more than 55000 tons,coal accounts for the dominant position in China's energy,especially in the fossil energy,the use of coal resources was reached more than 95%.China had a lot of coal reserves,there was a variety of coal,but the scarcity of coking coal resources per capita was far lower than in other major coal-producing country in the world.At present,China faced many challenges in the field of coal,in terms of coal workers,how to increase recovery was a serious problem.Coking coal was not only one of the indispensable raw metallurgical industry,coal coking and coal utilization has great significance.China production was about 1 billion tons of coking coal in 2010,the average yield of about 20%of middlings,it was used as power coal that resulting in greatly waste of rare types of coal.How to save and protection and rational utilization of mineral resources,improve utilization efficiency of coal and two times the level of resources recycling which was the primary task of coal workers.In this paper,the middlings of dissociation and separation of the Crushing and grinding,with the different degree of dissociation of middlings as the research object.The different Crushing degrees of coal are particle size distribution and experimental research,the density distribution of the different degree of dissociation,feasibility study of middlings from the coal recovery.Through grinding the dissociated middlings was separation experiment,discusses the relationship between middlings and clean coal recovery of different degree of dissociation,discusses the effect of different medicament on the dissociation of separation properties of middlings.And through the JS94H-type electrophoresis apparatus,HARKE-SPCA contact angle apparatus and VERTEX-70 infrared spectrometer,test and analyze the variation of surface properties of middle coal in the depth of the dissociated.The research results are as follows.1.By the testing and analysis of coal samples,the clean coal yield recovery was 6.10%.The accuracy of separation was low that middlings has a little clean coal.2.Coal samples was crushed to13mm,6mm,3mm,1mm,the different of crushing products with decreased sized of ash have reduced.3.With the deepening of coal crushed,the clean coal yield recovery has increased.Coal samples was crushed to 1mm,clean coal yield increased by 10.30%,reaching 16.40%.4.Coal samples was girnded to less than 200 mesh number in 30.65%,60.78%,83.77%,92.07%,93.91%,98.88%,99.37%,99.87%,100%,the clean coal yield recovery has increased.With increased girnded time,the clean coal yield recovery first increased and then decreased.5.Coal samples was grinded to less than 200 mesh number in 93.91%,the clean coal yield recovery was 9.50%after the flotation.6.The surface electrical properties and surface contact angle of coal samples of coal samples had no obvious change after grinded dissociation.