Characterisation of copper slag in view of metal recovery

In this study, the copper bearing particle of a fayalitic copper slag was assessed using quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) and X-ray computed tomography (CT). The copper content of the slag was, similar to 0.87 wt-%. Copper in this slag was present as sulphidic droplets. The content and particle size distribution of the major sulphide phases (bornite, chalcopyrite and chalcocite/digenite) were quantified using QEMSCAN. The copper bearing particles had a wide particle size distribution from a few micrometres up to millimetre level. Large copper bearing particles (> 100 mu m) were composed mainly of bornite and chalcocite/digenite and tended to accumulate in the lower part of the slag layer. As characterised with CT, similar to 70% of the copper value was present in these large copper bearing particles.