Numerical modelling of conductive particle trajectories in roll-type electrostatic separators

Several attempts have already been made to simulate particle trajectories in roll-type electrostatic separators. However, the predictive value of the results is limited by an excessive number of simplifying assumptions regarding the electric field distribution, as well as particle charging and discharging mechanisms. The present work is aimed at improving the existing models by taking into account: (i) the non-uniformity of the electric field in the active zone of the separator; (ii) the effect of spark discharges occuring between the electrodes. Based on previous observations, the conductive particles were assumed to lift-off when no longer exposed to corona discharge. The numerical simulations were performed for particles of various sizes. The electric field was computed in each point of the trajectory using a finite element program. It was found that: (i) some of the smaller particles impact the static electrode and are deviated to the middling compartment of the collector; (ii) field annealing which accompanies spark discharges significantly affect the trajectories of conductive particles. The results of this study could guide the design of new electrostatic separation applications.

[1]  A. D. Moore.  Electrostatics and its applications , 1973 .

[2]  Ion I. Inculet,et al.  The modern problems of electrostatics with applications in environment protection , 1999 .

[3]  Lucian Dascalescu,et al.  Corona–Electrostatic Separation: An Efficient Technique for the Recovery of Metals and Plastics From Industrial Wastes , 1993 .

[4]  Lucian Dascalescu,et al.  ELECTROSTATIC SEPARATION OF INSULATING AND CONDUCTIVE PARTICLES FROM GRANULAR MIXES , 1998 .

[5]  Malay K. Mazumder,et al.  Efficiency of electrostatic separation of minerals from coal as a function of size and charge distributions of coal particles , 1999, Conference Record of the 1999 IEEE Industry Applications Conference. Thirty-Forth IAS Annual Meeting (Cat. No.99CH36370).

[6]  L. Dascalescu,et al.  High-Voltage Monitoring in Electrostatic Separators , 2007, IEEE Transactions on Industry Applications.

[7]  Lucian Dascalescu.  Mouvements des particules conductrices dans un séparateur à haute tension pour matériaux granulaires , 1994 .

[8]  James E. Lawver.  State of the Art of Electrostatic Separation of Minerals , 1969 .

[9]  Lucian Dascalescu,et al.  Charges and forces on conductive particles in roll-type corona-electrostatic separators , 1993 .

[10]  Lucian Dascalescu,et al.  Factors which influence the insulation-metal electroseparation , 1993 .

[11]  Ion I. Inculet,et al.  ELECTROSTATIC SEPARATION OF PLASTICS FOR RECYCLING , 1998 .

[12]  Y. Higashiyama,et al.  RECENT PROGRESS IN ELECTROSTATIC SEPARATION TECHNOLOGY , 1998 .

[13]  Lucian Dascalescu,et al.  Corona and electrostatic electrodes for high-tension separators , 1993 .

[14]  A. Iuga,et al.  Electrostatic separation of metals and plastics from granular industrial wastes , 1998, Conference Record of 1998 IEEE Industry Applications Conference. Thirty-Third IAS Annual Meeting (Cat. No.98CH36242).

[15]  A. Iuga,et al.  Numerical analysis of the electric field in plate-type electrostatic separators , 1998, Conference Record of 1998 IEEE Industry Applications Conference. Thirty-Third IAS Annual Meeting (Cat. No.98CH36242).

[16]  Lucian Dascalescu,et al.  Electrostatic Technologies for the Recycling of Non-Ferrous Metals and Plastics from Wastes , 1999 .

[17]  Lucian Dascalescu,et al.  Numerical analysis of the electric field of roll-type electrostatic separators , 1993 .

[18]  Cylindrical conductive particles in the proximity of an electrode affected by a high-intensity electric field , 1996 .