Mohammad Aali Dehchenari - BSc of Mechanic Engineering,Young Researchers and Elite Club, Majlesi Branch, Islamic Azad University, Isfahan, Iran
Saeed Hosseinpoor - Instructor of Civil Engineering – Structure, Department of Environmental Health, School of Health, Urmia University of Medical Sciences, Urmia, Iran
Rahim Aali - Assistant Professor of Environmental Health Engineering, Department of Environmental Health Engineering, Faculty of Nursing and Health, Urmia University of Medical Sciences, Urmia, Iran
Nilowfar Salighehdar Iran - Ph.D Student of Health Education and Health Promotion, Department of Health Education and Health Promotion,Tehran University of Medical Sciences, Tehran, Iran

Background: This research studied the feasibility of a simple method for extracting gold from central processing units (CPUs) of computer circuit boards without solvent. Methods: Ceramic and composite CPUs of computer circuit boards were used. Gold was extracted using ahydrometallurgical method in six stages: grinding of CPUs, leaching in nitric acid, leaching in aqua regia, removing the excess nitric acid, extracting the gold, washing and purifying the gold deposits. Measurementsof extracted precious metals were carried out by inductively coupled plasma (ICP). Results: The results indicated that mean concentrations of gold in the first and second stages of leachingwere 0.138 and 31.16 mg/L, respectively. Following the washing stage, the concentration of gold in the final deposit was 25 mg/L. The purity rate of the final deposit was 83.9%, and the final gold recovery yielded82.3%. Conclusion: The results of this study indicated there is a potential for extracting a high percentage of precious metals from e-wastes without solvent.

E-waste, Gold extraction, Hydrometallurgical method