Full Characterization of Sarcheshmeh and Khatoon-Abad Copper Anode Slimes: Characterization Impact on the Decopperization Operation

Copper anode slime, a valuable by-product generated during the electrorefining process, is an important secondary resource for the recovery of metals, such as gold, silver, selenium, tellurium, PGMs and copper. A full characterization of the anode slime is an essential part of the efficient recovery of these valuable metals. In this research, the refinery slimes of the Sarcheshmeh and Khatoon-Abad copper complexes, were fully characterized and compared using inductively coupled plasma (ICP), X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and particle size analysis. Besides the bottom cell slime characterization, properties of the Sarcheshmeh’s adherent slime was also analyzed and correlated. Sarcheshmeh copper slime particle size was found much smaller than the Khatoon-Abad slime. For both slimes though, the major part the gold and tellurium are located in larger than 38-micron particles. The main difference in thermal analysis of the two slime samples was originated from their selenium content difference. This has caused the higher concentration of non-selenide copper compounds at Khatoon-Abad slime, resulted in its easier copper recovery. Decopperization of both bottom-cell slimes were investigated and a significant difference in copper dissolution behaviors of the two slimes were observed due to their characteristic difference including the copper-selenide phases and capsulated copper in the barium sulfate agglomerates. Copper dissolution from Khatoon-Abad slime was observed to reach 90% comparing to 40% for Sarcheshmeh slime using atmospheric leaching.