Rare earth magnets based upon neodymium-iron-boron (NdFeB) are employed in many high tech applications, including hard disk drives (HDDs). The key elements in manufacturing NdFeB magnets are rare earth elements (REEs) such as neodymium. This element has been subject to significant supply shortfalls in the recent past. Recycling of NdFeB magnets contained within waste of electrical and electronic equipment (WEEE) could provide a secure and alternative supply of these materials. Various recycling approaches for the recovery of sintered NdFeB magnets have been widely explored. Hydrogen decrepitation (HD) can be used as a direct reuse approach and effective method of recycling process to turn solid sintered magnets into a demagnetised powder for further processing. In this work, sintered Nd-Fe-B magnets were processed without prior removal of the metallic protective layer using the thermal HD process as an alternative recycling method. The gas sorption analyzer was used to determine the quantity of the hydrogen absorbed by a samples of magnets, under controlled pressure (1, 2, 3, and 4 bar) and temperature (room, 100, 300, and 400?C) conditions, using Sieverts? volumetric method. The composition and morphology of the starting and the extracted/disintegrated materials were examined by ICP, XRD, and SEM-EDS analysis.

This article presents a method of reusing aluminum scrap from alloy 6082 using the hot extrusion process. Aluminum chips from milling and turning processes, having different sizes and morphologies, were cold pressed into briquettes prior to hot pressing at 400 °C at a ram speed of 2 mm/s. The study of mechanical properties combined with observations of the microstructures, as well as tests of density, hardness and electrical conductivity were carried out. On the basis of the results, the possibility of using the plastic consolidation method and obtaining materials with similar to a solid ingot mechanical properties, density and electrical conductivity was proven. The possibility of modifying the surface of consolidated aluminum scrap was tested in processes examples: polishing, anodizing and coloring. For this purpose, a number of analyses and tests were carried out: comparison of colors on color histograms, roughness determination, SEM and chemical composition analysis. It has been proven there are differences in the surface treatment of the solid material and that of scrap consolidation, and as such, these differences may significantly affect the final quality.

This article presents the results of research on the recycling of non-ferrous metals from PCB scrap using melting in metallic lead. The idea of this process is to dissolve (transfer) metals from PCB scrap in lead, and then liquation them by cooling the lead-metals alloy. PCB scrap was crushed and then melted into liquid lead. The lead after process was then poured into the casting mold and its chemical composition was examined. Among the various metals in the PCB scrap, copper and tin in particular are dissolved in lead. The more scrap dissolved in lead, the higher the concentration of copper and tin in the alloy. The highest obtained concentration of copper in lead were about 2.2 wt.%, and for tin about 0.8 wt.%.

E3S Web of Conferences, open access proceedings in environment, energy and earth sciences

The dissolution of MnO2 from tantalum capacitor scrap using organic acids in various process conditions was studied. The initial materials were of two types: LTC (leaded tantalum capacitors) and SMDTC (surface-mounted device tantalum capacitors). The research materials were prepared by pyrolysis, grinding and sieving and the preparation processes were characterized. Dissolution of MnO2 was carried out with the use of sulfuric acid solutions with the addition of acetic, ascorbic, citric and oxalic organic acids. Results show that the addition of organic acids significantly improves dissolution yields (72-94 vs 90-99 % for H2SO4 and acid mixtures, respectively). In practice, a concentration of organic acid above 1 M results in the complete removal of MnO2.

The research material was a strongly alkaline solution containing germanium, lead, arsenic, zinc and trace amounts of other metals, obtained by leaching of industrial material. The aim of the study was to determine the behavior of the above metals in the precipitation process using various acidic agents: HCl, H2SO4, C2H2O4, C6H8O7. The tests were carried out in a wide pH range. The behavior and role of individual ions during the acidification of germanate solution is poorly understood, hence the study of this subject was undertaken. The resulting precipitates and solutions were examined by XRF, XRD and ICP techniques. The recovery yields of individual elements was determined. Attempts were also made to precipitate Ge from a synthetic solution in order to compare the results obtained for the solution of an industrial solution. This research shows that the presence of other ions interferes with the selective recovery of Ge from research solutions. Generally, it can be said that the method of recovery by acidification is effective at low concentrations of the solution's components.