Abstract
Oxidized black copper ores are known for their difficulty in dissolving their components of interest through conventional methods. This is due to its non-crystalline and amorphous structure. Among these minerals, copper pitch and copper wad are of great interest because of their considerable concentrations of copper and manganese. Currently, these minerals are not incorporated into the extraction circuits or left untreated, whether in stock, leach pads, or waste. For the recovery of its main elements of interest (Cu and Mn), it is necessary to use reducing agents that dissolve the present MnO2, while allowing the recovery of Cu. In this research, the results for the dissolution of Mn and Cu from a black copper mineral are exposed, evaluating the reducing effect of NaCl for MnO2 through pre-treatment of agglomerate and curing, and subsequently leaching in standard condition with the use of a reducing agent (Fe2+). High concentrations of chloride in the agglomerate process and prolonged curing times would favor the reduction of MnO2, increasing the dissolution of Mn, while the addition of NaCl did not benefit Cu extractions. Under standard conditions, low Mn extractions were obtained, while in an acid-reducing medium, a significant dissolution of MnO2 was achieved, which supports the removal of Cu.
Highlights
The interactions that occur in mineral deposits through geological agents help the formation of new mineral species [1]
It can be seen that without the use of a reducing agent, it is not possible to dissolve the Mn present in the black copper sample and, besides, a beneficial effect cannot be appreciated by adding chloride to the system. This is consistent with the results obtained by Benavente et al [7], where Mn was not dissolved for a black copper ore under standard conditions
When a previous agglomerate process is added by adding NaCl, a positive effect on the dissolution of Mn is generated
Summary
The interactions that occur in mineral deposits through geological agents help the formation of new mineral species [1]. Black copper ores are a resource that is generally not incorporated into the extraction circuits or left untreated, whether in stock, leach pads, or waste [6,7] This is due to the difficulty of recovering elements of interest like Cu or Mn by conventional hydrometallurgical processes since the complex structure is non-crystalline or amorphous [8]. Several studies have been carried out to extract these elements from marine nodules and other manganese minerals, which generates alternatives for processing by similar leaching systems. In a more recent study by Cerda et al [21], pre-treatment experiments were carried out for a copper sulphide mineral (chalcopyrite), where sulfuric acid (20 kg/t) and sodium chloride were added at different concentrations A leaching process was carried out under standard conditions and adding a reducing agent (Fe2+ )
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