Green Process of Metal Recycling: Coprocessing Waste Printed Circuit Boards and Spent Tin Stripping Solution

Abstract

Electronic waste (e-waste), including waste printed circuit boards (PCBs), has caused global concern owing to its potential environmental pollution and rich resource content. Previous studies have indicated that urban mining for metals recycling can decrease energy consumption and pollutants emission compared to the extraction of metals from natural minerals. During the production of PCBs, a large amount of spent tin stripping solution (TSS) is simultaneously generated, containing the significant amounts of metal ions and residue nitric acid. In this study, the coprocessing of waste PCBs and spent TSS at room temperature was proposed and investigated, with the aim of developing an environmentally sound process to address these problems. This coprocessing approach proved to be effective. 87% of the Sn–Pb solder, 30% of the Cu, 29% of the Fe, and 78% of the Zn was leached from waste PCBs with spent TSS after 2 h, at room temperature. Moreover, approximately 87% of the electronic components were dismantled from waste PCBs. About 99% of the Sn, Pb, Fe, Cu, and Zn were recovered from the leaching solutions by chemical precipitation. The proposed green process has substantial advantages over traditional recovery methods of heating waste PCBs, in terms of both material and energy efficiency.

Roasting Pretreatment Combined with Ultrasonic Enhanced Leaching Lead from Electrolytic Manganese Anode Mud

“…This is mainly because the electrolytic manganese anode mud is heated to promote the thermal stress between the useful mineral and the gangue, causing cracks in the mineral particles. The dissociation effect that is difficult to achieve by the conventional calcination method is achieved, the reaction area of the useful mineral interface is increased, and the reaction contact area with the leaching solvent is increased [17,18]. Considering the relationship between leaching rate and economy, the subsequent leaching experiments were carried out under the premise of 1123 K high temperature roasting pretreatment.…”

Preparation of Calcium Stannate from Lead Refining Dross by Roast–Leach–Precipitation Process

“…The E-pH diagrams of Sn-H 2 O system shown in Figure 6 indicate that the transformation of Sn → Sn(IV) occurs in the whole pH range investigated. Sn(IV) exists in the form of SnO 2− 3 in the alkaline solution, and it tends to precipitate as Sn(OH) 4 and further dissolve as Sn 4+ with the decrease of the pH value [40,41]. Based on the above analysis, tin can be selectively extracted with an alkaline solution.…”

Increasing lithium extraction performance by adding sulfonated poly (ether ether ketone) into block‐copolymer ethylene vinyl alcohol membrane

“…In previous reports, the pros-and-cons of various lithium extraction technologies (i.e. chemical precipitation, 28,29 ion exchange, [30][31][32][33] nanofiltration, 34-36 electrodialysis 37-39 and adsorption [40][41][42] ) have been discussed and we have identified membrane extraction as one of most suitable candidates. 1,27 Commercial ion exchange membranes have been utilized for promotion of ion diffusion in membrane contactors.…”

“…In previous reports, the pros‐and‐cons of various lithium extraction technologies (i.e. chemical precipitation, ion exchange, nanofiltration, electrodialysis and adsorption) have been discussed and we have identified membrane extraction as one of most suitable candidates …”