Processing of copper anode slimes by aeration leaching (decopperization) and flotation

With the declining quality of feedstock in the copper industry, maintaining metal recovery rates and controlling production costs for non-ferrous and precious metals has become increasingly critical. A key research priority is therefore the development of processing strategies that not only concentrate target metals into flotation products but also recover valuable minor elements previously lost with slags and flue dust. One approach involves designing process flowsheets that integrate hydrometallurgical and beneficiation operations. Previous studies have demonstrated the effectiveness of combining autoclave leaching and flotation for decopperization of copper anode slimes and their concentration in gold, silver, and selenium. However, autoclave leaching requires significant capital and operating expenditures. For this reason, a series of tests was carried out on aeration leaching (decopperization) of copper anode slimes followed by flotation, yielding promising results. This study examined the influence of aeration leaching conditions (temperature, agitation, and specific oxidant consumption—air and oxygen), disintegration of the leached product, and flotation parameters on the selective separation of oxide and chalcogenide phases and the quality of the resulting concentrates. Based on the experimental results, process operations were developed that make it possible to concentrate precious metals in copper anode slimes two- to threefold without the use of autoclave leaching. Optimal conditions and equipment configurations were determined for deep decopperization of slimes (to less than 0.5–0.8 % residual copper). An acceptable degree of separation of precious-metal chalcogenides from lead and antimony oxides was achieved, enabling downstream recovery of marketable products from the respective concentrates. Analytical characterization of the products was performed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The findings contribute to the development of an integrated hydrometallurgical technology for processing copper anode slimes.

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