Mahsa Pourmohammad

Waste printed circuit boards (WPCBs) account for approximately 3%–6% of electrical and electronic equipment (WEEE) and contain high concentrations of valuable metals such as copper, often at levels higher than those in natural ores. Consequently, WPCB recycling represents an important opportunity for resource recovery through urban mining and supports the transition toward a circular economy. This study investigates the application of a Falcon centrifugal concentrator for the gravity separation of metallic and non-metallic fractions from WPCBs, with a focus on fine particles below 300 μm. Despite its potential, this method has received little attention, particularly in research. Optimal operating conditions were identified as 80 Hz rotation frequency and 1 LPM water flow rate for particles −100 μm, and 30 Hz rotation frequency and 3 LPM water flow rate for particles in the −300 + 100 μm range. Under these conditions, copper recovery reached 98.25% with Cu content of 10.34% for the coarse fraction and 95.97% with Cu content of 4.47% for the fine fraction after a cleaner stage. The results demonstrate that Falcon gravity concentration is an efficient technique for recovering fine metallic particles and outperforms the multi-gravity separator (MGS). A sustainable beneficiation flowsheet is proposed to enhance metal recovery and reduce environmental impacts.

Waste printed circuit boards (WPCBs) are one of the fastest-growing waste streams and pose a significant environmental challenge while also representing a valuable secondary resource due to their rich metal content, particularly copper (Cu). Since effective recovery of metals requires mechanical pre-treatment and advanced characterization, WPCB boards were subjected to size reduction and then characterized through X-ray fluorescence (XRF), inductively coupled plasma optical emission spectroscopy (ICP-OES), scanning electron microscopy (SEM-EDS), and mineral liberation analysis (MLA). Results indicated that copper is predominantly found in coarser particle sizes due to its ductility, while glass fibers and ceramics dominate finer fractions. Liberation studies revealed that Cu is essentially free in fine particles (300 μm) were treated on a shaking table, achieving a Cu recovery of 95%, while fine particles (<300 μm) were processed using a multi-gravity separator (MGS), with recoveries of 94% for 100 × 300 μm and 81.5% for <100 μm size fractions. This study presents a gravity-based separation strategy that combines shaking tables and MGS to optimize Cu recovery from automotive WPCBs. To the authors’ knowledge, the MGS application for WPCBs has received little attention, despite its strong potential for separating this type of waste. The proposed methodology enhances the concentration and purity of the metallic fraction (in this case, Cu), especially in fine particles, which are challenging to work with, while reducing environmental impacts through minimal chemical use, thereby contributing to sustainable e-waste recycling.

The process of recycling lithium-ion batteries is drawing global attention due to a shortage of critical raw materials (CRMs), a sustainable and environmentally friendly approach that meets the needs of many industries. Characterization is an important step in the recycling of black mass resulting from the processing of a lithium-ion battery at the beginning and the end of the processes because of the complexity of the feed material and to evaluate the process. This research proposes a beneficiation flowchart for the further separation of graphite particles from metal oxides based on the characterization results by combining scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), laser-induced breakdown spectroscopy, laser scattering particle size distribution analysis, X-ray fluorescence (XRF), X-ray diffraction analysis (XRD), inductively coupled plasma–optical emission spectroscopy (ICP-OES), and thermogravimetry–differential thermal analysis (TG/DTA). Based on these characterization results, it is suggested that black mass with coarser particle size (0.2–1 mm) goes to the liberation process for beneficiation of the Al and Cu and black mass with a size range of 0.053–0.2 mm goes to the froth flotation for beneficiation of the Mn, Ni, Fe, and Co. Finally, a black mass with a size range of <0.053 mm goes through the froth flotation after the agglomeration process.