Without the use of appropriate recycling technologies, the growing amount of electronic waste in the world can be a threat to the development of new technologies, and in the case of improper waste management, may have a negative impact on the environment. This is due to the fact that this waste contains large amounts of valuable metals and toxic polymers. Therefore, it should be recycled in accordance with the assumptions of the circular economy. The methods of mechanical recovery of metals from electronic waste, including printed circuits, may be widely used in the future by waste management companies as well as metal production and processing companies. That is why, a well-known and easily applicable electrostatic separation (ES) method was used to recover metals from printed circuit boards. The grain class of 0.32 - 0.10 mm, obtained after grinding the boards, was fed to a separator. Feed and separation products were analyzed by means of ICP-AES, SEM/EDS and XRD. The concentrate yield obtained after electrostatic separation amounted to 32.3% of the feed. Its density was 11.1 g/cc. Out of the 91.44% elements identified in the concentrate, over 90% were metals. XRD, SEM observations and EDS analysis confirmed the presence of non-metallic materials in the concentrate. This relatively high content of impurities indicates the need to grind printed circuit board into grain classes smaller than 0.32-0.10 mm.

The article presents the assessment of solutions and dried residues precipitated from solutions after the bioleaching process of Printed Circuit Boards (PCB) utilizing the Acidithiobacillus ferrooxidans. The obtained dried residues precipitated from bioleaching solution (leachate) and control solution were tested using morphology, phase, and chemical composition analysis, with particular emphasis on the assessment of crystalline and amorphous components. The analysis of the dried residues from leachate after bioleaching as well as those from the sterile control solution demonstrated a difference in the component oxidation—the leachate consisted of mainly amorphous spherical particles in diameter up to 200 nm, forming lacy aggregates. In the specimenform control solution larger particles (up to 500 nm) were observed with a hollow in the middle and crystalline outer part (probably Fe2O3, CuFeS2, and Cu2O). The X-ray diffraction phase analysis revealed that specimen obtained from leachate after bioleaching consisted mainly of an amorphous component and some content of Fe2O3 crystalline phase, while the dried residue from control solution showed more crystalline components. The share of the crystalline and amorphous components can be related to efficiency in dissolving metals during bioleaching. Obtained results of the investigation confirm the activity and participation of the A. ferrooxidans bacteria in the solubilization process of electro-waste components, with their visible degradation–acceleration of the reaction owing to a continuous regeneration of the leaching medium. The performed investigations allowed to characterize the specimen from leachate and showed that the application of complementary cross-check of the micro (SEM and S/TEM) and macro (ICP-OES and XRD) methods are of immense use for complete guidance assessment and obtained valuable data for the next stages of PCBs recycling.