Distribution of Ni, Co, Ag, Au, Pt, Pd between Copper Metal and Silica Saturated Iron Silicate Slag

Dmitry Sukhomlinov, Pekka Taskinen

This work is focused on improved handling of raw materials and resource savings by an increased recovery of the selected elements in the copper making process. Distribution measurements for Ni and Co as well as for selected precious (Ag, Au) and platinum group (Pt, Pd) metals between copper metal and iron silicate slag were conducted at 1300 °C. Oxygen partial pressure was controlled in the range from 10-8 to 10-4 atm. The selected experimental conditions simulate copper converting and pyrorefining processes. The actual experiments were conducted in small fused silica crucibles, where four phases (solid silica, iron silicate slag, copper metal and gas) equilibrium was attained. The samples were equilibrated in a vertical gas tight tube furnace and then quenched. Polished sections of the samples were examined by scanning electron microscope with energy-dispersive X-ray spectroscopy detector, electron probe X-ray microanalysis and laser ablation-inductively coupled plasma-mass spectrometry. The distribution coefficients of the metals were calculated as LMem/s = [wt.-% Me in copper]/(wt.-% Me in slag). The experimentally determined thermodynamic data in this study is a new contribution for the understanding of the elements deportment in the copper making processes.