This study compares the results of the dewatering of coal preparation plants tailings by conventional coagulation processes using different types of coagulants and by electrocoagulation methods carried out by two different electrodes. When the results of electrocoagulation and conventional coagulation experiments were compared (aluminium electrode vs. ferric chloride), it was found that the coagulation efficiencies for both methods were similar, in the case that the aluminium electrode was used, there was a 22.2% decrease in the process cost compared to the use of ferric chloride.