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Academic/Researcher at the Department of Mining Metallurgical Engineering at the Universidad Católica del Norte. Line of interest: Hydrometallurgy and minor elements
The dissolution of copper sulphide ores continues to be a challenge for the copper industry. Several media and leaching alternatives have been proposed to improve the dissolution of these minerals, especially for the leaching of chalcopyrite. Among the alternatives, pretreatment prior to leaching was proposed as an option that increases the dissolution of copper from sulphide ores. In this study, a mineral sample from a copper mining company was used. The copper grade of the sample was 0.79%, and its main contributor was chalcopyrite (84%). The effect of curing time (as pretreatment) in a chloride media on copper sulphide ore was evaluated at various temperatures: 25, 50, 70 and 90 °C. The pretreated sample and leaching residues were characterized by X-ray diffraction, scanning electron microscopy, and reflected light microscopy. Pretreatment products such as CuSO4, NaFe3(SO4)2(OH)6, and S0 were identified although with difficulty, due to the low presence of chalcopyrite in the initial sample (1.99%). Under the conditions of 15 kg/t of H2SO4, 25 kg/t of NaCl, and 15 days of curing time, a copper extraction of 93.1% was obtained at 90 °C with 50 g/L of Cl− and 0.2 M of H2SO4.
Víctor Quezada; Antoni Roca; Oscar Benavente; Montserrat Cruells; Evelyn Melo; María Hernández. Pretreatment to Leaching for a Primary Copper Sulphide Ore in Chloride Media. Metals 2021, 11, 1260 .
AMA StyleVíctor Quezada, Antoni Roca, Oscar Benavente, Montserrat Cruells, Evelyn Melo, María Hernández. Pretreatment to Leaching for a Primary Copper Sulphide Ore in Chloride Media. Metals. 2021; 11 (8):1260.
Chicago/Turabian StyleVíctor Quezada; Antoni Roca; Oscar Benavente; Montserrat Cruells; Evelyn Melo; María Hernández. 2021. "Pretreatment to Leaching for a Primary Copper Sulphide Ore in Chloride Media." Metals 11, no. 8: 1260.
The need to sustainably produce raw materials encourages mining companies to develop and incorporate new economically and environmentally efficient processes. Therefore, there is a need to investigate the behavior and stabilization of hazardous elements present in effluents from metal recovery processes such as arsenic. This study evaluates the incorporation of an effluent solution from a copper smelter that is to be treated in a copper hydrometallurgical plant (heap leaching). The treatment is applied to recover compounds of interest such as copper, acid and water, in addition to confining impurities as stable residues in the leach residues. Here, we assess the capacity of the mineral to retain arsenic. To do this, a mixed solution of effluent and process solution was prepared, with a concentration of 1 g/L of arsenic. The solution was irrigated in leach columns loaded with a heap mineral with varying pH levels (0.8; 1.5 and 2) and solution potentials (510 and 540 mV). The concentrations of arsenic and iron in the solution and in the solid residues were measured to determine the capacity of the mineral to retain arsenic and how it was retained. The pH level plays an important role since, at a higher pH, the presence of arsenic and iron in the solution decreases, therefore increasing in the solid residue. Finally, a retention of 57% of arsenic is reached at pH 2. The characterization of the residues by scanning electron microscopy (SEM) confirms that arsenic is associated with Fe, S and O, forming ferric arsenates, while an X-Ray analysis identifies the arsenic compounds as crystalline scorodite.
Oscar Benavente; María Cecilia Hernández; Evelyn Melo; Víctor Quezada; Yan Sepúlveda; Yuri Zepeda. Stabilizing Arsenic in Copper Heap Leaching Residues. Metals 2020, 10, 1242 .
AMA StyleOscar Benavente, María Cecilia Hernández, Evelyn Melo, Víctor Quezada, Yan Sepúlveda, Yuri Zepeda. Stabilizing Arsenic in Copper Heap Leaching Residues. Metals. 2020; 10 (9):1242.
Chicago/Turabian StyleOscar Benavente; María Cecilia Hernández; Evelyn Melo; Víctor Quezada; Yan Sepúlveda; Yuri Zepeda. 2020. "Stabilizing Arsenic in Copper Heap Leaching Residues." Metals 10, no. 9: 1242.
This article presented the behavior of ores containing black copper under acid leaching. The solution potential was modified by adding agents, and five leaching conditions were evaluated, one as a control based on sulfuric acid leaching (conventional), and the others by changing the solution potential with: ferrous sulfate (FeSO4), white metal (Cu2S), sulfur dioxide (SO2), and ozone (O3). Leaching behavior was evaluated with laboratory bottle (ISO-pH) and column leaching tests. Two ores samples from the Lomas Bayas mine were used. The samples, identified as low (LG) and high grade (HG), were characterized as 0.13–0.25% Cu and 0.15–0.38% Mn, respectively. The mineralogical analysis indicated that black copper represented around 20% of total Cu (0.05% Cu). The results of the bottle tests indicated that the solution potential decreased with the addition of reducing agents, while the copper extraction rate with the HG sample increased to 83.7%, which exceeded the extraction rate obtained by conventional acid leaching by 25%. Ozone did not favor the extraction of Mn and Cu extraction when the solution potential increased. Cu and Mn extraction were directly related. The results of the column leaching tests showed that it was possible to maintain the solution potential at values below 600 mV (SHE) with the addition of white metal and sulfur dioxide while obtaining the highest copper extraction rate of approximately 60%, which was 18% higher than the rate obtained with conventional leaching. Sulfuric acid consumption was 11 kg/t over 45 days of leaching.
Oscar Benavente; Ma.Cecilia Hernández; Evelyn Melo; Luis Ardiles; Víctor Quezada; Yuri Zepeda. Copper Extraction from Black Copper Ores through Modification of the Solution Potential in the Irrigation Solution. Metals 2019, 9, 1339 .
AMA StyleOscar Benavente, Ma.Cecilia Hernández, Evelyn Melo, Luis Ardiles, Víctor Quezada, Yuri Zepeda. Copper Extraction from Black Copper Ores through Modification of the Solution Potential in the Irrigation Solution. Metals. 2019; 9 (12):1339.
Chicago/Turabian StyleOscar Benavente; Ma.Cecilia Hernández; Evelyn Melo; Luis Ardiles; Víctor Quezada; Yuri Zepeda. 2019. "Copper Extraction from Black Copper Ores through Modification of the Solution Potential in the Irrigation Solution." Metals 9, no. 12: 1339.
Black copper oxides are amorphous materials of copper-bearing phases of manganese. They are complex mineral compounds with difficult to recognize mineralogy and have slow dissolution kinetics in conventional hydrometallurgical processes. This study evaluates the effects of various leaching media on copper dissolution from black copper minerals. Leach of a pure black copper sample from Lomas Bayas Mine and another from a regional mine were characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray diffraction (XRD), scanning electron microscopy (SEM), Qemscan and mechanically prepared for acid leaching under standard, oxidizing and reducing conditions through the addition of oxygen, iron sulfate or sulfur dioxide, respectively. Standard and high potential leaching (770 mV (SHE)) results in a copper dissolution rate of 70% and manganese dissolution rate of 2%. The addition of potential reducing agents (FeSO4 or SO2) decreases the redox potential to 696 and 431 mV, respectively, and favors the dissolution of manganese, thus increasing the overall copper extraction rate. The addition of SO2 results in the lowest redox potential and the highest copper extraction rates of 86.2% and 75.5% for the Lomas Bayas and regional samples, respectively, which represent an increase of 15% over the copper extract rates under standard and oxidizing conditions.
Oscar Benavente; María Cecilia Hernández; Evelyn Melo; Damián Núñez; Víctor Quezada; Yuri Zepeda. Copper Dissolution from Black Copper Ore under Oxidizing and Reducing Conditions. Metals 2019, 9, 799 .
AMA StyleOscar Benavente, María Cecilia Hernández, Evelyn Melo, Damián Núñez, Víctor Quezada, Yuri Zepeda. Copper Dissolution from Black Copper Ore under Oxidizing and Reducing Conditions. Metals. 2019; 9 (7):799.
Chicago/Turabian StyleOscar Benavente; María Cecilia Hernández; Evelyn Melo; Damián Núñez; Víctor Quezada; Yuri Zepeda. 2019. "Copper Dissolution from Black Copper Ore under Oxidizing and Reducing Conditions." Metals 9, no. 7: 799.