Study On The Quality Improvement Of Shendong Coarse Slime In Spiral Separator

Coarse coal slime is a slime with a particle size ranging from 3 to 0.5 mm.In the production and transportation of coal preparation plants,a large amount of coarse slime is wasted every year and cannot be effectively processed.With the coarse coal slime of the second phase and third system of the Daliuta Coal Preparation Plant of the National Energy Investment Group Shendong Coal Washing Center as the research object,using the spiral separators of different specifications and models to explore the effect of the structure and process conditions on the final product separation effect.As a result,the material distribution characteristics of the groove surface of the spiral separator at different particle sizes were explored through layered and band-interception sampling,which provided ideas for the application and development of the spiral separator.In terms of structural parameters,using the different number of turns and screw pitch of the spiral separator and combining the changing rules of the characteristics of each product,the system has investigated the influence law of the structure of the spiral separator on the separation result.The results show that:a smaller pitch is beneficial to the deviation of medium and high-density particles toward the inner edge of the tank,so that the ash content of clean coal is reduced.With the increase of the number of turns,the movement of the material is relatively stable,and the yield and ash content of clean coal are on the rise.From the analysis of the particle size composition of clean coal,it can be seen that with the increase of the number of turns,the whole material shifts to the outer edge of the groove,making the ash and content of clean coal rise.In terms of process parameters,it can be found that when the width of the clean coal discharge port increases,the clean coal yield increases and the ash content increases.As the concentration of pulp increases,the ash content of clean coal decreases..The increase of flow rate is beneficial to the spreading of materials on the surface of the tank;as the flow rate increases,the yield of clean coal increases,and the ash content reaches the minimum when the flow rate is 0.88 L/s.The content of 0.5 to 0.25 mm and 0.25 to 0.125 mm in clean coal products increases,and the low ash content reduces the overall ash content of clean coalAfter determining the separation process parameters,the spiral separator was evaluated for the re-selection process,and the two-stage distribution curve was drawn to obtain a one-stage distribution curve ?50=1.629,E=0.2160,I=0.3434;two-stage distribution curve?50=1.759,E=0.2685,I=0.3538.It can be seen that the separation density of the two sections is relatively high,and the separation accuracy is low.According to the analysis of the product characteristics of layered and band-interception sampling,the upper yield of the whole-grain grade material products shows an "M" type change trend,the lower yield shows a trend of increasing first and then decreasing,and the ash content gradually decreases from the inside out.The material yield and ash content of<0.25 mm showed a decreasing trend from inside to outside.The single-grain grade 1?0.5 mm and 0.5?0.25 mm yield ash content are obviously different.The particle size composition analysis of the mixed granular grade products found that the groove surface motion behavior of different granularity grade materials is inseparable from the feed granularity composition,such as the ash and yield content of 0.25?0.125 mm belonging to the full grade product are obviously different from the product of 0.25?0.125 mm product which is in<0.25 mm material.The spiral separator with a pitch of 240 mm and a diameter of 400 mm was modeled and analyzed with solidworks simulation:the velocity of the flow field of the spiral separator increased with the decrease of the height,and the flow velocity increased continuously;The flow velocity in the outer area is higher,the flow velocity near the tank is smaller,and the flow velocity in the upper area is high.The total pressure of the spiral separator increases with the decrease of the height;the pressure distribution is relatively uniform on the same radial section;the axial total pressure increases continuously with the decrease of the height.The particle size of the input particles of the fixed spiral separator can analyze the particles with three densities of 1.6 g/cm3,5.0 g/cm3,and 7.5 g/cm3.After being uniformly fed from the entrance,the particles are gradually concentrated,and the concentration is completed in 4 circles.The high-density gyration radius is greater than the low-density gyration radius,and the high-density particles are closer to the inner edge of the groove.The flow field of the spiral separator can be obtained by studying the equal density particles.The particle concentration of particles with different particle sizes after 1.5 cycles is completed.It can be obtained by selecting a single particle particle trajectory.At the beginning,the particles are located at the outer edge,and after 1.5 s,they are concentrated on the inside of the device.