Ion metallic extractions from various solids were performed by means of electrokinetic processes that use ion-exchange membranes. These new techniques elaborated initially for soils electroremediation experiments have been generalized to sludge treatment and also to kaolin bleaching and ore leaching. All experiments are based on electrodialyses with a feed compartment composed of a mixture of solids and an appropriate solution. In this work, the contradictory results obtained for the different kinds of treated solids have shown the versatility of the process. The extraction efficiency depends upon the nature of the solid and its structure and composition. The relation,of the feasibility of the electrokinetical treatment of a solid and its physical parameters is discussed and a correlation is attempted. Thus, before performing any electrokinetical application, the solid sample studied should be well characterized for the prediction of the suitability of the treatment.