| The amount of tailings in China has exceeded 15 billion tons,which has caused environmental damage and waste of resources.Aiming at the secondary recovery of polymetallic tailings in China,we can realize the secondary resource utilization,reduce environmental pollution,improve the recovery rate of useful metals in polymetallic tailings,and realize the high value and reduction of polymetallic tailings,In this pape r,a method of enrichment of multi-component particles is proposed,which is driven by airflow and driven by Coanda adsorption traction to promote the migration of particles with different densities,so as to realize the separation of particles with differ ent densities,and provide an effective way for the pollution-free secondary recovery of polymetallic tailings.(1)Based on the study of the phenomenon and principle of Coanda effect and the characteristics of curved flow attached to the wall,a kinetic model for the separation of multi-component particles was established.The tangential and radial motion of particles in the Coanda region was studied.The main factors affecting the separation characteristics of particles in the Coanda region were obtained,including particle density,particle size and secondary air inlet.(2)Taking copper tailings as the research object,a simplified copper silicon mixed particle system was established,and the particle separation was simulated an d analyzed.Firstly,the influence of curvature of Coanda ring on jet wall attachment effect is studied.It is found that with the increase of curvature radius of Coanda ring,the recovery proportion of copper particles in the fourth loop(distribution dis tance is 560-710mm)decreases first and then increases.When curvature radius of Coanda ring is 175 mm,jet wall attachment effect is the best.Secondly,the influence of jet velocity on separation of copper particles is studied When the flow velocity is 4.4 m/s,the enrichment ratio of copper particles in the third recycle port(distribution distance is 410-560 mm)reaches the best;when the jet velocity is 5.3 m/s,the recovery ratio of copper particles in thethird recycle port reaches the best;finally,through the research on the influence of auxiliary air flow(secondary air inlet)on particle separation,it is found that the enrichment effect of copper particles in the third recycle port is the best when the secondary air inlet velocity is 1m/s.(3)The experimental platform was established to study the separation characteristics of multi-component particles with the curvature radius of Coanda ring,different jet velocity and different secondary air inlet velocity as the main influencing factors;a.With the increase of Coanda curvature radius,the proportion of copper particles in the fourth loop increases first and then decreases.When the Coanda curvature radius is 175 mm,the jet wall attachment effect is the best;b.When the jet velocity is 4.4 m/s,the grade of copper particles in the third recovery port is the best,which is 56.08%,and the enrichment rat io is 5.90;when the jet velocity is 5.3 m/s,the recovery ratio of copper particles in the third recovery port is the best,which is 61.67%,and the separation effect of copper particles in the high-speed jet is poor;c.When the secondary air inlet velocity is 1 m/s,the grade of copper particles increases about 3 percentage points,but the recovery proportion decreases by 9 percentage points.Appropriate secondary air inlet velocity can improve the enrichment of copper particles,and larger secondary air inlet velocity can reduce the separation effect of copper particles;The simulation and experiments show that the multi-component particles have good separation performance under the Coanda effect,which can improve the grade of valuable metals in tailings,and has reference significance for the clean secondary recovery of multi-metal tailings. |
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