Leaching Chalcocite in Chloride Media—A Review
Abstract
:1. Introduction
2. Fundamentals
3. Operational Variables
3.1. Effect on Chloride Concentration
3.2. Effect on Stirring Speed
3.3. Effect on Acid Concentration
3.4. Particle Size Effect
3.5. Effect of Temperature
3.6. Effect of Redox Potential
3.7. Effect of Oxidizing Agents
3.7.1. Air
3.7.2. Ferric Ions
3.7.3. MnO2
4. Conclusions
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
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Mineral | Composition | System | Stability |
---|---|---|---|
Chalcocite (low T) | Cu1.99–2S | Monoclinic | T < 105 °C |
Chalcocite (high T) | Cu1.98–2S | Hexagonal | ~105 °C < T < ~425 °C |
Chalcocite (high P and T) | Cu2S | Tetragonal | 1 kbar < P, T < 500 °C |
Djurleite | Cu1.93–1.96S | Monoclinic | T < 93 °C |
Digenite (low T) | Cu1.75–1.8S | Cubic | Metastable |
Digenite (high T) | Cu1.73–2S | Cubic | 83 °C < T |
Anilite | Cu1.75S | Orthorhombic | T < 72 °C |
Investigation | Leaching Agent | Parameters Evaluated | Temperature (°C) | Reference | Max Cu Extraction (%) |
---|---|---|---|---|---|
The kinetics of leaching chalcocite (synthetic) in acidic oxygenated sulfate–chloride solutions | NaCl, H2SO4, HCl, HNO3, and Fe3+ | Oxygen flow, stirring speed, temperature, acid concentration, ferric ion concentration, chloride concentration, and particle size | 65–94 | [24] | 97 |
Leaching kinetics of digenite concentrate in oxygenated chloride media at ambient pressure | CuCl2, HCl, and NaCl | Effect of stirring speed, oxygen flow, cupric ion concentration, chloride concentration, acid concentration, and temperature effect | 50–100 | [61] | 95 |
Leaching of sulfide copper ore in a NaCl–H2SO4–O2 media with acid pre-treatment | NaCl and H2SO4 | Chloride concentration, effect of agitation with compressed air, percentage of solids, and particle size | 20 | [62] | 78 |
The kinetics of dissolution of synthetic covellite, chalcocite, and digenite in dilute chloride solutions at ambient temperatures | HCl, Cu2+, and Fe3+ | Potential redox effect, chloride concentration, acid concentration, temperature, dissolved oxygen, and pyrite effect | 35 | [38] | 98 |
Leaching of pure chalcocite in a chloride media using seawater and wastewater | NaCl, H2SO4, and Cl− from seawater and wastewater | Chloride and acid concentration | 25 | [13] | 68 |
Modeling the kinetics of chalcocite leaching in acidified cupric chloride media under fully controlled pH and potential | HCl, CuCl2, NaCl, KCl, CaCl2, and MgCl2 | Chloride concentration, cupric concentration, particle size, and temperature | 25–65 | [63] | 98 |
Leaching of pure chalcocite in a chloride medium using wastewater at high temperature | H2SO4 and Cl− from wastewater | Temperature effect | 65–95 | [43] | 97 |
The response of the sulfur chemical state to different leaching conditions in chloride leaching of chalcocite | FeCl3, CuCl2, and HCl | Chloride concentration, temperature, and potential redox effect. | 35–55 | [42] | 88 |
Leaching of pure chalcocite with reject brine and MnO2 from manganese nodules | H2SO4, MnO2, and Cl− from seawater and wastewater | MnO2, chloride, and acid concentration | 25 | [46] | 71 |
Experimental Parameters | Low | Medium | High |
---|---|---|---|
Time (h) | 4 | 8 | 12 |
Cl− concentration (g/L) | 20 | 50 | 100 |
H2SO4 (mol/L) | 0.5 | 1 | 2 |
Experimental Conditions and Results | [13] | [46] |
---|---|---|
Temperature (°C) | 25 | 25 |
Particle size of Cu2S (μm) | −147 + 104 | −147 + 104 |
H2SO4 concentration (mol/L) | 0.5 | 0.5 |
MnO2/Cu2S ratio (w/w) | - | 0.25/1 |
Dissolution in seawater after 4 h (%) | 32.8 | 35.6 |
Dissolution in reject brine after 4 h (%) | 36 | 40 |
Dissolution in seawater after 48 h (%) | 63.4 | 64.7 |
Dissolution in reject brine after 48 h (%) | 64.6 | 66.2 |
Parameters | First Stage | Second Stage |
---|---|---|
Chloride concentration | Increases dissolution kinetics | Help prevent passivation |
Stirring rate | It is not relevant | It is not relevant |
Acid concentration | A low concentration of H2SO4 (0.02 mol/L) is sufficient to dissolve the mineral. | Increases dissolution kinetics |
The same results are obtained between 0.1 and 1 mol/L of H2SO4. | ||
Particle size | Increase in dissolution kinetics. | Slight increase in dissolution kinetics |
Temperature | Significantly accelerates dissolution | Significantly accelerates dissolution |
Helps prevent passivation | ||
Redox potential | Low redox potential is required (≥500 mV) | High redox potential values are required (>650 mV) |
Oxidizing agents (air, Fe3+, MnO2) | Increases dissolution kinetics by adding low concentrations | Increases dissolution kinetics, but only at high concentrations |
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Toro, N.; Moraga, C.; Torres, D.; Saldaña, M.; Pérez, K.; Gálvez, E. Leaching Chalcocite in Chloride Media—A Review. Minerals 2021, 11, 1197. https://doi.org/10.3390/min11111197
Toro N, Moraga C, Torres D, Saldaña M, Pérez K, Gálvez E. Leaching Chalcocite in Chloride Media—A Review. Minerals. 2021; 11(11):1197. https://doi.org/10.3390/min11111197
Chicago/Turabian StyleToro, Norman, Carlos Moraga, David Torres, Manuel Saldaña, Kevin Pérez, and Edelmira Gálvez. 2021. "Leaching Chalcocite in Chloride Media—A Review" Minerals 11, no. 11: 1197. https://doi.org/10.3390/min11111197
APA StyleToro, N., Moraga, C., Torres, D., Saldaña, M., Pérez, K., & Gálvez, E. (2021). Leaching Chalcocite in Chloride Media—A Review. Minerals, 11(11), 1197. https://doi.org/10.3390/min11111197