Karim Medles

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Identification of the optimal operating conditions and evaluation of their robustness are critical issues for the industrial application of electrostatic separation techniques. In spite of extensive investigations performed in recent years, no standard procedure is available for guiding the research of the set point and for minimizing the process(More)
The dual corona-electrostatic electrodes consist of one or several ionizing elements (wires, needles, and blades) attached to a metallic support. This paper analyzes the characteristic features of a particular type of such electrodes and formulates recommendations on their design and utilization. The experiments focused on several models of dual(More)
Tribocharged mixed granular materials are commonly separated in the electrostatic field generated between two vertical plate electrodes. However, the existing technologies are not appropriate in sorting coarse granules (size > 2 mm) in which the effect of gravity is stronger than the Coulomb forces. The aim of the experiments reported in this paper is to(More)
Tribocharging of pulverulent materials in compressed-air devices is a typical multifactorial process. Quantification of the effects of the factors and of their interactions is a prerequisite for the development of new tribocharging devices for industrial applications. This paper aims at demonstrating the interest of using the design of experiments(More)
Plate-type electrostatic separators are commonly used for the selective sorting of conductive from nonconductive constituents of a granular mixture. This paper addresses the more delicate issue of granular materials that are characterized by finite nonzero resistivities. The study was conducted with three materials having similar granule size range and(More)
Parallel wire-plate electrode arrangements are widely used to generate corona discharges in various electrostatic processes. The present paper analyzes the characteristic features of a slightly-modified such electrode configuration. In all the experiments, a stainless steel wire, diameter 0.18 mm or 0.57 mm was employed as corona electrode, energized from a(More)
Identification of the optimal operating conditions and evaluation of their sensibility to changes in certain critical factors are critical issues for the industrial application of electrostatic separation techniques. The authors have already elaborated a procedure for set-point identification and robustness testing of a roll-type corona-electrostatic(More)
Multivariate control charts are commonly used for monitoring processes, the quality of which is determined by two or more correlated output variables. The aim of this paper is to point out the effectiveness of multicriterion control charts for supervising the variability of the outcome of an electrostatic separation process. The experiments were carried out(More)
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(More)
Mixed granular insulating materials can be electrostatically separated by tribocharging them in a fluidized bed affected by an electric field orthogonally oriented to the direction of the fluidization air. The aim of this paper is to optimize the operating conditions of a novel pilot-scale tribo-aero-electrostatic separator, i.e., maximize the total mass of(More)