Nadjem Abdelkader2024-02-142024-02-142018-12-18http://dspace.univ-khenchela.dz:4000/handle/123456789/858The development of electrostatic applications involving electrical charges, such as the electrostatic separation process, is often accompanied by the need to develop triboelectric charging methods to control and promote the level of charges accumulated on the surfaces of insulating materials for the proper functioning of this process. The objective of this work is to contribute in improving the triboelectric charging of plastic granular materials using the surface treatment technique by dielectric barrier discharge (DBD) under atmospheric conditions. The first part of this work was devoted to the study of the effect of several electrical and geometrical factors of DBD on the discharge characteristics and, therefore, the surface modification of plastic granular materials and their triboelectric behavior. During our experiments, the DBD-treated particles acquired a high electrical charge and we obtained satisfactory results. The study of these DBD factors has also determined the optimal values to improve the acquired charge and the coordination of all these factors can produce better results. The experimental study also demonstrated the importance of using surface treatment of particles prior their charging to improve the separation results of a composite mixture of two types of materials by evaluating recovery rates and purity of the separated products. We also presented the experimental study of an electrostatic separator in order to contribute to the improvement of the free-fall separator and thus to prove the effectiveness of the proposed prototype. The results show the effectiveness and the importance of introducing an inclined plane and its role in improving the recovery rate of separated products. Very high recovery rates were obtained.frThesis