Abstract:
This research examined the optimum conditions of chemical coagulation and electrocoagulation process for separate TiO from cyanide treatment wastewater. In chemical coagulation process : coagulants, initial pH and coagulant dosages were varied. Effect of the influencing factors : electrical current, initial pH, retention time, electrode size and conductivity were explored in electrocoagulation process. The optimum initial pH in chemical coagulation proce3ss for PACI, CaCI and FeSO coagulations were 12.0 12.5 and 12.0 and coagulant dosages wer4 1.5 1.0 and 1.5 grams per liter, respectively. In electrocoagulation process, amount of floc and percentage of tIo REMOVAL INCREASED WHEN ELECTRICAL CURRENT WAS MORE THAN 0.25 AMPERES. The optimum retention time was half an hour. Although higher percentage of TiO removal was associated with higher retention time and electrode size, the power energy and losing aluminum increased. Amount of floc were too much when the electrode size was larger than 6x6.5 square centimeters. The number of TiO reuse times were four for TiO from PACI coagulation and electrocoagulation. The cyanide removal efficiency of these processes was more than 90% in 420 minutes. In contrast, the remaining chloride ion on surface of TiO from CaCI coagulation retarded cyanide photooxidation reaction whose first order rate constants much were lower than those of new TiO .