Research On Design And Separation Performance Of Instant Overflow Chute

Coal is the main energy source in China,which accounts for more than 60% of the primary energy consumption.With the increasing mechanization of coal mining and the deterioration of coal storage conditions,the proportion of fine and ultrafine coal in raw coal is increasing year by year,resulting in a decline in resource quality.It is necessary to be significantly separated them.On the basis of summarizing the separation mechanism of traditional fan-shaped chute,seeks to develop a new type of chute that can immediately overflow and collect the overflow in sections by designing and testing the overflow from in this paper,and finally obtains a new type of slime gravity separation equipment.Taking the-1mm slime of coal preparation plant in Tunlan as the research object,the structural design and experimental exploration of chute equipment were carried out.Through the experimental research,the design size of chute,reasonable installing angle,appropriate coal slurry concentration,feed flow rate,tip shrinkage ratio,the height of tail-discharge and other conditions were achieved.The effective sorting area and the rate of tailings were determined by changing the position and number of collecting grid bars at the top.Through the position and number of bottom grid baffle,it is determined that bottom grid baffle has influence on tailing ash in the separation process.Based on the continuous overflow,a segmented instantaneous overflow chute is designed to increase the identification of the chute length and realize the effective separation of the overflow.Computational fluid dynamics was applied to the modeling and numerical simulation of overflow chute.The turbulence model was used.The distribution of the velocity and water flow rate was shown by simulating the different installation angles and feeding speeds.And the relationship between flow velocity and separation is analyzed.Main conclusions of the paper are:(1)Hydraulic chute is one kind of separation equipment with simple structure,no moving parts and obvious energy-saving advantages.In this paper,the continuous overflow or subsection overflow chute separator is designed,which is a new type of chute separator and has potential application value in the separation of coarse coal slime.(2)Within a certain range,if it has the larger the chute angle and the larger the feed quantity,it will have the greater the sorting strength and the higher the purity of the gangue discharged.The results of flow field simulation show that the intensity of separation is mainly due to the increase of velocity and velocity gradient.(3)It is difficult to get the final product in the first stage of chute separation.Therefore,a multi-stage separation process based on chute is proposed to realize the separation of low-ash cleaned coal,medium-ash coal and high-ash gangue.