On the Kinetic Behavior of Recycling Precious Metals (Au, Ag, Pt, and Pd) Through Copper Smelting Process

Xingbang Wan,Pekka Taskinen,Lotta Kleemola,Ari Jokilaakso,Hugh O’Brien,Lassi Klemettinen

doi:10.1007/s40831-021-00388-6

Xingbang Wan, Pekka Taskinen + Show 4 more

Open Access

https://doi.org/10.1007/s40831-021-00388-6

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Abstract

The recycling and recovery of precious metals from secondary materials, such as waste-printed circuit boards, are an important area of circular economy research due to the limited existing resources and increasing amount of e-waste produced by the rapid development of technology. In this study, the kinetic behavior of precious metals Au, Ag, Pt, and Pd between copper matte and iron-silicate slag was investigated at a typical flash smelting temperature of 1300 °C in both air and argon atmospheres. SEM–EDS, EPMA, and LA-ICP-MS-advanced analysis methods were used for sample characterization. The results indicate that precious metals favor the matte phase over slag, and the deportment to matte occurred swiftly within a short time after the system had reached the experimental temperature. With increasing contact times, the precious metals were distributed increasingly into the sulfide matte. The distribution coefficients, based on experimentally measured element concentrations, followed the order of palladium > platinum > gold > silver in both air and argon, and the matte acted as an efficient collector of these precious metals. The obtained results can be applied to industrial copper matte smelting processes, and they also help in upgrading CFD models to simulate the flash smelting process more precisely.Graphical

Highlights

Due to technological advances and the improvement of economic and social conditions around the globe, the number of electronic devices in total and per capita is increasing
The reactions proceeded quickly, as the matte (A) and fayalite FeOx–SiO2 slag (B) phases already began to form after 10 s, which is consistent with the rapid reaction phenomena occurring in the flash smelting process [46]
These larger precious metals (PMs) clusters and droplets were avoided in the electron probe micro-analysis (EPMA) analyses, which was used to detect the average concentrations of PMs in the matte

Summary

Introduction

Due to technological advances and the improvement of economic and social conditions around the globe, the number of electronic devices in total and per capita is increasing. Studies on the kinetic behavior of precious metals in the matte-slag system are lacking [37], and more research is urgently needed to optimize the methods to recover precious metals from WPCBs through the copper smelting process. The time dependency of precious metal (Au, Ag, Pt, and Pd) distribution was experimentally investigated in laboratory-scale copper matte smelting conditions.

Results

Conclusion