Extraction of Copper from Copper-Bearing Materials by Sulfation Roasting with SO2-O2 Gas

Xingbang Wan,Junjie Shi,Pekka Taskinen,Ari Jokilaakso

doi:10.1007/s11837-020-04300-7

Abstract

Recycling metals from secondary materials and more complex ores has recently been attracting more attention, creating a need for more precise separation methods of different elements. This study proposed a sulfation-roasting method and designed thermodynamic conditions to selectively facilitate the formation of copper sulfate while separating iron as oxide.The roasting behaviors for chalcopyrite, copper slag, and pure copper compounds were investigated in a 0.5% SO2–0.5% O2–99% Ar atmosphere at 600°C. X-ray fluorescence spectroscopy, x-ray diffractometry, scanning electron microscopy, and energy dispersive x-ray spectrometry were used to characterize the raw materials and roasting products.The proposed methodology was confirmed for a complete separation of Cu from Fe, and, further, the sulfation-roasting mechanism of chalcopyrite was confirmed by thermodynamic calculations and experimental observations. These will provide a theoretical basis for copper recycling from both complex primary and secondary copper-bearing materials.

Highlights

This study proposed a sulfation-roasting method and designed thermodynamic conditions to selectively facilitate the formation of copper sulfate while separating iron as oxide
Copper is an important nonferrous metal that has been used for thousands of years due to its versatile and highly applicable properties.[1]
Copper smelting slag and chalcopyritic copper concentrate were roasted for 8 h and 24 h, respectively, to verify the roasting behavior of residual copper in smelting slag

Summary

Introduction

Copper is an important nonferrous metal that has been used for thousands of years due to its versatile and highly applicable properties.[1] The increasing demand for copper and depletion of high-grade ores have prompted intensive investigation on metal recovery from low-grade ores and secondary copperbearing resources.[2] For low-grade ores or secondary resources, such as copper slag and e-waste (waste of electronics and electrical equipment), utilization is challenging because of the complexity of their composition. Addition to the common metals, such as Fe, Cu, Al, and Ni, it contains trace amounts of precious, rare and rare earth elements (Au, Ag, Pt, Pd, Cd, Se, As, Co, Te, Ta, Ru, Ge, Ga, Rh, Sn, Pb, and Bi), which make recycling quite demanding.[4,5] With increased public attention on environmental protection, studies of cleaner and truly circular approaches to produce copper from complex copper-bearing resources are urgently needed

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