Coal Slime Separation And Process Research In Inclined Channel

This paper mainly focuses on the problem that the traditional flotation method is difficult to separate and cost high-grade oxidized coal slurry.The idea of consisting of a set of parallel inclined channels above a conventional fluidised bed and increasing the settlement area and settlement time through the inclined channel to strengthen the settlement effect is proposed.In this paper,a two-stage separation method is adopted,in which one section adopts a narrow inclined channel for the separation of slime,and the second section uses a wide-pitch channel for removing high-ash fine mud in a overflow product.The effects of the variation of the inclined channel spacing and water velocity on the separation and desilting process of the slime were investigated under the same conditions of the same feed concentration and solids treatment.The sedimentation velocity of particles in a narrow inclined channel depends mainly on the particle density,particle size and inclined channel spacing.In order to obtain the theoretical water velocity of the particles moving in the inclined channel,the free sedimentation process of the single particle is used as the calculation criterion,and the water velocity vector and the theoretical derivation method are combined to obtain the relationship between the water velocity of the particles in the inclined channel and the inclined channel spacing,the vertical section rising water velocity,the particle size and the density.Through this relationship,the water velocity in the channel under different spacing conditions is calculated to elutriate the slime.Inclined channel spacings of 1,2,4,and 6 mm were used in the work through self-designed equipment.Explore the optimal spacing of the low-order oxidized slime sorting and desliming process and the channel water velocity.According to the research on the whole-grade elutriating of low-order oxidized coal slurry: Under the same feed concentration and solid processing capacity,changing the channel spacing has a great influence on slime sorting.In the fine coal slime,the ash changes are basically the same,and the fine-grained coal slime basically does not separate with the change of the channel spacing.In the coarse-grained grade,significant separation occurs with the change of the pitch,but the smaller the pitch,the smaller the variation,and the sorting effect is basically the same.Separated in 4mm and 6mm inclined channels,the size of-0.045 mm in the overflow accounts for 70.31% and 79.14%.It shows that most of the high-ash fine mud does not separate into the overflow product,which raises the overall ash.This part of high-ash fine mud pollution into the clean coal caused pollution,indicating that fine-grained coal is not suitable for separation with wide spacing.Under different water speed conditions,the overflow ash decreases with the increase of the average particle size,and the higher the water velocity,the higher the overflow ash and yield.At a water velocity of 0.0063 m/s and 0.0076 m/s,the yield of-0.045 mm in the overflow product is 65.08% and 72.78%.Most of the fine-grained coal slime enters the overflow product without separation,resulting in high ash content in the overflow product.In the process of increasing water velocity,the distribution of coal slime with water is relatively serious,and the overflow yield is basically the same.This also confirms that the higher the water velocity in the channel,the higher the ash content and yield of the overflow product.At 6mm spacing,changing the water velocity of the inclined channel has a great influence on the de-fluiding process of an overflow product.Under different channel water velocities,the ash content of coal ash basically increases with the increase of average grain size,while the ash content of fine-grained coal ash is basically the same.The ash content of coarse-grained coal ash basically increases with the increase of water velocity.According to the separation and desilting research experiments of low-order oxidized coal slime: It is determined that a section of slime separation uses a 2 mm spacing,a channel water velocity of 0.004 m/s,and a two-stage deliming process uses a 6 mm spacing and a channel water velocity of 0.0048 m/s.Further,34.65% of the raw coal ash is reduced to about 19.65%.