Study On The Coal Slurry Sedimentation Characteristics Based On PIV

Slime water sedimentation is critical to production of coal preparation plant and the slime water treatment directly affects the economic benefit and production environment of coal preparation plant.In recent years,the content of Slime in coal preparation plant is increasing and its own complex physical and chemical properties causes the difficulty of settlement.Thus,that determining pharmacy system,mechanism for in-depth study basing on analysis of flock-characteristics has become an increasingly important subject.With samples from Wangjialing gas coal,the optimum dose was gained through the flock sedimentation test when different electrolytes,flock and reagent compound taken into consideration.Based on the optimum dose,using tracker-test of flock formed by different mechanism by PIV,calculating velocity and granularity of flock,and then calculating effective density of the flock according to the Stokes formula.Ultimately,the mathematical model between granularity and the velocity of flock and the the mathematical model between granularity and effective density were established.Conclusions are as follows:1.Size distribution analysis shows that fine-grained material accounts35.81% and ash accounts 41.22%,which is relatively high,in the sample of Wangjialing gas coal.XRD analysis shows that the contents of kaolin,quartz and calcium carbonate are relatively higher and the content of refined coal is lower.Not conducive to slime water sedimentation.2.The addition of flock alone can significantly improve the slime water settling effect.The optimum dosage of CPAM,NPAM and APAM was 500g/t,200g/t,500g/t,respectively.The addition of inorganic electrolyte coagulant alone is not obvious to improve the light transmittance of slime water.The higher the ionic valence,the stronger the potential compression ability;and the less dosage required;the optimal dosage of AlCl₃ and FeCl₃ is 0.048mmol/L and0.072mmol/L;for CaCl₂ and MgCl₂,the optimal dosage is 3.2mmol/L.3.When adding organic flocculating agent alone,especially for CPAM and NPAM,larger flock were formed with settling faster,lower density of flock.While adding electrolyte alone goes against flock growth,with lower sedimentation velocity,larger effective density of flock.The velocity and granularity of flock have seen obvious improvement when the combination of different electrolytes and APAM were used together instead of use one along each time,and compaction rate of flock is significantly larger by using the combination than it is by using flocculant along.4.The relationship between sedimentation rate and flock granularity matches the linear relationship of w_s=ad+b.The R² is usually lower,ranging from 0.5 to 0.9.And this low R² value also reflects the wide range ofmorphology and composition of the flock,which also reflects the large variation in the velocity of flock at a given flock size.5.The relationship between effective density of flock and flock size matches the exponential relation of ??=e^?.