Investigation of new hydrometallurgical processes for recovery of metals from electronic waste

E-waste is a major source of base and precious metals, and it is the world's fastest-growing type of waste. Galvanic leaching of metals from e-waste (waste television (ATVDK) and computer (ABilDK) circuit boards) with a pyrite concentrate (PyC) was investigated using shaking flask and stirred reactor tests in this thesis. The parameters affecting galvanic leaching of e-waste (leaching method, PyC dosage, acid type concentration, e-waste/PyC particle size, temperature, oxidizer type and concentration, solids ratio, the addition of activated carbon, and chloride, etc.) were studied using statistical or conventional experimental design methods. Stirred reactor leaching has achieved faster and higher leaching efficiencies than shaking flask leaching. The most important parameter affecting galvanic leaching of e-waste was discovered to be PyC dosage, and as the dose increased, so did the galvanic leaching rate and copper efficiency. Similarly, temperature (20-80 °C range) was found to be an important parameter that positively affected the leaching rate and yield. Galvanic leaching tests at high temperature (80 °C) (mechanical mixing, 120 min) yielded 14-23 % (in the absence of PyC) and 85-90 % copper yields depending on the PyC: E-waste dosage (ratio: 0-14:1). Galvanic leaching of WTVBs and WPCBs in sulfate media was found to increase by 23-30% in copper with the addition of chloride (5-10 g/L) and AC (3.3-10 g/L), respectively. There was no discernible effect of acid concentration on galvanic leaching. In addition to copper, the behavior of other metals in galvanic leaching was investigated (Fe, Co, Ni, Zn, Ag, Au, Pd, and so on). Despite its tendency to lose effectiveness, PyC can be reusable (3 times) in galvanic leaching. The galvanic behavior of copper and pyrite was investigated using electrochemical tests (CV, LP, and Tafel), and it was discovered that the galvanic leaching (current density) of copper increased 2-10 times in the presence of pyrite. The findings of this study indicate that galvanic leaching of pyrite materials such as flotation wastes/concentrates and e-waste, particularly copper, is an effective alternative method.