Abstarct: Electrochemical flotation has emerged as a new method that employs electrochemistry in flotation technology¬to increase its efficiency. Electrochemical parameters areapplied to control the oxidation and reduction reactions in flotation environment, in order to change the surface characteristics of theselected minerals.In this research,by applying the external potential in floatation and depression of sulfide minerals, the electrochemical flotation of chalcopyrite and molibdenite is investigated. The main objective of this research was to maximize the recovery of molibdenite in the concentrate while maximizing the recovery of copper in the tailings. By employing thismethod, in the absence of reagents and by controlling oxidation conditions, 73% recovery of molibdenite to concentrate and 76% recovery of copper to tailings was observed. In the situation the external potential was -1.5 volts, pulp potential was -56 milivolts and the pulp pH was 11.41. In the presence of sodium sulfide, 65% recovery of molibdenite in the concentrate and 99% recovery of copper in the tailings was observed. In this case, the external potential was -3 volts, pulp potential was -57.2 millivolts and the pulp pH was 12.2. These results showthat by using about 25% of the current plant consumption of sodium sulfide, the recoverycould be dramatically improved. In the situations where the pulp potential is positive (reduction conditions), the maximum depression of chalcopyrite occurs in the pulp potential of 256 to 286milivolts.The best results were obtained in conditions where the applied potential was +0.5volts,the pulp potential was +263 milivolts and pH was 7.45. The effect of pulp density in the electrochemical flotationwas experimentally examined. The results showed that, by decreasing pulp density, the effect of external potential on the depression of copper minerals wasincreased. Themain reason is that by decreasing the pulp density, penetration of electrical current increases. Among various types of electrodes(such as graphite, stainless steel and platinumelectrodes)the graphitic electrode wasshowed better results. In the presence of sodium sulphide, the molebdinte recovery was 96% and copper depression was 93%,with graphitic electrode. Using of rotor and stator as the working and counter electrodes, the molebdinte recovery was 92.5% and cooper depression was 87.3%. These results can be considered as a means to scale up the experimental resultsto industrial application. Cyclicvoltmeteric potential methods were used in the electrochemical flotation process to indentify the hydrophilic and hydrophobic mechanisms of minerals surfaces. Considering the voltgrams, it was observed that the peaks occurred at -0.9, -0.6, +0.6 and +1.4potentials,which are related to the oxides species absorbed on the electrode surface.The electrodes, in this case,were made of mineral samples such as chalcopyrite crystal, chalcocite crystal and bulk samples.