Leaching of Pure Chalcocite in a Chloride Media Using Sea Water and Waste Water

Abstract

Chalcocite is the most important and abundant secondary copper ore in the world with a rapid dissolution of copper in an acid-chloride environment. In this investigation, the methodology of surface optimization will be applied to evaluate the effect of three independent variables (time, concentration of sulfuric acid and chloride concentration) in the leaching of pure chalcocite to extract the copper with the objective of obtaining a quadratic model that allows us to predict the extraction of copper. The kinetics of copper dissolution in regard to the function of temperature is also analyzed. An ANOVA indicates that the linear variables with the greatest influence are time and the chloride concentration. Also, the concentration of chloride-time exerts a significant synergic effect in the quadratic model. The ANOVA indicates that the quadratic model is representative and the R2 value of 0.92 is valid. The highest copper extraction (67.75%) was obtained at 48 h leaching under conditions of 2 mol/L H2SO4 and 100 g/L chloride. The XRD analysis shows the formation of a stable and non-polluting residue; such as elemental sulfur (S0). This residue was obtained in a leaching time of 4 h at room temperature under conditions of 0.5 mol/L H2SO4 and 50 g/L Cl−.

Reducing-Effect of Chloride for the Dissolution of Black Copper

“…Currently, the mining industry must generate a new approach that helps overcome the stagnation in its growth. Despite its surplus-generating role, large-scale mining faces significant challenges such as the deterioration of the ore grade, increased operational costs, and input costs must be adjusted to the demand for sustainable development [23]. In recent years, in Chile the treatment of other commodities has been incorporated into the extraction processes, for example, the recovery of Mo together with the Cu in flotation processes has been encouraged [24].…”

Leaching Chalcopyrite with High MnO2 and Chloride Concentrations

“…The scarcity of fresh water in arid zones is an economic, environmental and social problem [39,40]. The availability of water resources and the quality of potable water have decreased significantly owing to human activity, whose effects at the small-scale are significant for the entire basin [41].…”

Leaching of Pure Chalcocite in a Chloride Media Using Waste Water at High Temperature

“…The temperature was controlled with an oil-heated circulator (Julabo, St. Louis, MO, USA). The tests were conducted at 65, 75, 85 and 95, • C, with 0.5 M of H 2 SO 4 , 100 and 39 g/L of chloride ion concentration; acid concentration and S/L ratio parameters were based in a previous research [19]. Furthermore, the assays were performed in duplicate, measurements (or analyses) were carried on 5 mL aliquot and diluted to a range of using atomic absorption spectrometry with a coefficient of variation ≤ 5% and a relative error between 5% to 10%.…”

“…Nevertheless, it was higher than that previously obtained with chalcocite and white metal The behavior of copper extraction by using wastewater does not change the trend. Wastewater has been previously evaluated for the dissolution of copper sulfides minerals [19,23,24] showing favorable outcomes, even better in some cases compared to seawater. In Figure 3, it is appreciated that the presence of chloride (39 g/L) would be enough to achieve high copper extraction and that other wastewater ions would not impact the chalcocite dissolution.…”