Supergravity Separation for Cu Recovery and Precious Metal Concentration from Waste Printed Circuit Boards

Abstract

Printed circuit boards (PCBs) contain both valuable metals and hazardous materials, thereby rendering them attractive secondary sources of metals, but also environmental contaminants. Thus, we herein report the use of supergravity separation for the recovery of copper (Cu) and the concentration of precious metals present in waste PCBs. At an optimized temperature of 1300 °C, a gravity coefficient of 1000, and a separation time of 5 min, the total recoveries of Cu, Zn, Pb, and Sn over the whole separation process were 97.80%, 95.59%, 98.29%, and 97.69%, respectively. Compared with the amounts of precious metals present in the original PCBs, the contents of Ag, Au, and Pd in the Cu alloy increased by 5.16, 2, and 1.85 times, respectively, while those in the final residues increased by 2.92, 1.59, and 1.54 times, respectively. Upon combination of the appropriate hydrometallurgical process and supergravity separation of metals or alloys, this clean and efficient process provides a new way to recycle valuable metals and effectively prevent environmental pollution from PCBs.

Cdynamic Change Characteristics of Ecosystem Fluxes in Cold Zone Wetlands in Northeast China

“…However, the study area is flat and the elevation difference is only 5 m. During the monitoring period, the temperature in the area was between -30 and 30 °C, and the highest monthly precipitation was 154 mm, with no adverse weather such as extreme temperatures and precipitation. Therefore, the effects of topography and climate in this study can be ignored (Eda et al, 2016;Evadzi et al, 2017;Kuang et al, 2017;Liu, 2018;Meng et al, 2018).…”

The Distribution Behavior of Elements during the Top-Blowing Smelting Process of Electronic Waste

“…At present, the harmless treatment of electronic waste has become a hot spot in the world. Many scholars have developed new methods for efficient and environmentally friendly recycling of valuable metals from electronic waste, which can be differentiated into the mechanical process, hydrometallurgical process, biometallurgical process and pyrometallurgical process [10,11]. Among them, the mechanical treatment method is used to separate and enrich valuable components by gravity separation, magnetic separation, electric separation, eddy current separation and flotation based on the differences in density, specific gravity, conductivity, magnetism and toughness among heavy metals, precious metals, silicon and resin in the electronic waste [12].…”

Combination of Pyrolysis and Physical Separation to Recover Copper and Tin from Waste Printed Circuit Boards

“…Currently, physical separation methods such as gravity separation, magnetic separation, and electrostatic separation are widely used in WPCBs, because of their low cost, high metal recovery, and lack of environmental pollution effects. 33,39,42,43 At present, the main research on the resource recovery of WPCBs tends to separate the metals from the non-metals, and then treats the nonmetals as harmless substances. A small number of researchers first performed this treatment on the non-metals of WPCBs, and then separated the metal and non-metal portions.…”