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David Torres; Luís Ayala; Ricardo I. Jeldres; Eduardo Cerecedo-Sáenz; Eleazar Salinas-Rodríguez; Pedro Robles; Norman Toro. Correction: Torres et al. Leaching Chalcopyrite with High MnO2 and Chloride Concentrations. Metals 2020, 10, 107. Metals 2021, 11, 1312 .
AMA StyleDavid Torres, Luís Ayala, Ricardo I. Jeldres, Eduardo Cerecedo-Sáenz, Eleazar Salinas-Rodríguez, Pedro Robles, Norman Toro. Correction: Torres et al. Leaching Chalcopyrite with High MnO2 and Chloride Concentrations. Metals 2020, 10, 107. Metals. 2021; 11 (8):1312.
Chicago/Turabian StyleDavid Torres; Luís Ayala; Ricardo I. Jeldres; Eduardo Cerecedo-Sáenz; Eleazar Salinas-Rodríguez; Pedro Robles; Norman Toro. 2021. "Correction: Torres et al. Leaching Chalcopyrite with High MnO2 and Chloride Concentrations. Metals 2020, 10, 107." Metals 11, no. 8: 1312.
Chile is the world's leading copper producer (28.3%) and maintains approximately 23.0% of current global reserves. Chile is faced with a significant risk posed by its collection of the most unsustainable and antiquated smelter operations among major copper producers worldwide. Moreover, forecasts also indicate a trend toward higher proportions of copper sulphide ores that carry high impurities, especially arsenic. To achieve the planned production increases, improve competitiveness in the global market, and reduce reliance on international smelting capacities, Chile must make significant and justifiable investment into new and/or existing smelting operations through equipment modernization. The required investment for upgrades may be on the order of billions of dollars. This review analyzes current roadblocks faced by the Chilean copper smelters and potential solutions according to environmental, economic and strategic factors. Recent advances in smelting technologies have focused on flash and bath smelting; despite a general trend toward flash furnace systems, recent bath furnace methods (e.g. China's SKS-BBS) are equally promising, particularly for varying and complex feeds. Strategic policies should focus on regionalized, non-integrated custom smelters, which can handle ores from a variety of sources while reducing overall operating costs. The government must play a fundamental role to incentivise the investments necessary to develop new smelter operations and upgrade existing infrastructure. With a large portion of copper concentrate exports coming from privately owned mines, synergistic efforts with industry partners will be crucial to increase overall smelting capacity and position Chile as a global leader in the smelting of copper concentrates.
Kevin Pérez; Norman Toro; Edelmira Gálvez; Pedro Robles; Ryan Wilson; Alessandro Navarra. Environmental, economic and technological factors affecting Chilean copper smelters – A critical review. Journal of Materials Research and Technology 2021, 15, 213 -225.
AMA StyleKevin Pérez, Norman Toro, Edelmira Gálvez, Pedro Robles, Ryan Wilson, Alessandro Navarra. Environmental, economic and technological factors affecting Chilean copper smelters – A critical review. Journal of Materials Research and Technology. 2021; 15 ():213-225.
Chicago/Turabian StyleKevin Pérez; Norman Toro; Edelmira Gálvez; Pedro Robles; Ryan Wilson; Alessandro Navarra. 2021. "Environmental, economic and technological factors affecting Chilean copper smelters – A critical review." Journal of Materials Research and Technology 15, no. : 213-225.
This research aims to analyze the impact of sodium tripolyphosphate (STPP) as a rheological modifier of concentrated kaolin slurries in seawater at pH 8, which is characteristic of copper sulfide processing operations. The dispersion phenomenon was analyzed through chord length measurements using the focused beam reflectance measurement (FBRM) technique, complementing size distributions in unweighted and square-weighted modes. The reduction of the rheological properties was significant, decreasing from 231 Pa in a reagent-free environment to 80 Pa after the application of STPP. A frequency sweep in a linear viscoelastic regime indicated that by applying a characteristic dosage of 0.53 kg/t of STPP, the pulp before yielding increases its phase angle, which increases its liquid-like character. Measurements of the chord length verified the dispersion of particles, which showed an apparent increase in the proportion of fine particles and a reduction of the coarser aggregates when STPP was applied. Measurements of the zeta potential suggested that the high anionic charge of the reagent (pentavalent) increases the electrostatic repulsions between particles, overcoming the effect of cations in seawater. The results are relevant for the mining industry, especially when the deposits have high contents of complex gangues, such as clays, that increase the rheological properties. This increases the energy costs and water consumption needed for pumping the tailings from thickeners to the tailing storages facilities. The strategies that allow for the improvement of the fluidity and deformation of the tailings generate slack in order to maximize water recovery in the thickening stages.
Williams Leiva; Norman Toro; Pedro Robles; Edelmira Gálvez; Ricardo Jeldres. Use of Multi-Anionic Sodium Tripolyphosphate to Enhance Dispersion of Concentrated Kaolin Slurries in Seawater. Metals 2021, 11, 1085 .
AMA StyleWilliams Leiva, Norman Toro, Pedro Robles, Edelmira Gálvez, Ricardo Jeldres. Use of Multi-Anionic Sodium Tripolyphosphate to Enhance Dispersion of Concentrated Kaolin Slurries in Seawater. Metals. 2021; 11 (7):1085.
Chicago/Turabian StyleWilliams Leiva; Norman Toro; Pedro Robles; Edelmira Gálvez; Ricardo Jeldres. 2021. "Use of Multi-Anionic Sodium Tripolyphosphate to Enhance Dispersion of Concentrated Kaolin Slurries in Seawater." Metals 11, no. 7: 1085.
The low grade of copper deposits and the use of the froth flotation process have caused excessive tailing production. In recent years, experts have looked for new alternative methods to improve this situation. Black copper minerals are abundant resources not exploited by large-scale copper mining and possess high Mn concentrations. On the other hand, manganese nodules are submarine resources and show high concentrations of Cu, Ni, Fe, and, mainly, Mn. However, both mineral resources are refractory to conventional leaching processes, and so a reducing agent is necessary for their treatment. We studied the use of tailings obtained from the flotation of foundry slags with a high content of Fe3O4 as reducing agents at different MnO2/tailings ratios and H2SO4 concentrations. Mn dissolution was compared in marine nodule and black copper minerals samples. It was found that higher Mn dissolutions are obtained from marine nodules, likely due to the acid consumption created by Cu dissolution from black copper minerals. The remnant elements in manganese nodules were leached under an oxidant condition.
Carlos Moraga; Eduardo Cerecedo-Saenz; Javier González; Pedro Robles; Francisco Carrillo-Pedroza; Norman Toro. Comparative Study of MnO2 Dissolution from Black Copper Minerals and Manganese Nodules in an Acid Medium. Metals 2021, 11, 817 .
AMA StyleCarlos Moraga, Eduardo Cerecedo-Saenz, Javier González, Pedro Robles, Francisco Carrillo-Pedroza, Norman Toro. Comparative Study of MnO2 Dissolution from Black Copper Minerals and Manganese Nodules in an Acid Medium. Metals. 2021; 11 (5):817.
Chicago/Turabian StyleCarlos Moraga; Eduardo Cerecedo-Saenz; Javier González; Pedro Robles; Francisco Carrillo-Pedroza; Norman Toro. 2021. "Comparative Study of MnO2 Dissolution from Black Copper Minerals and Manganese Nodules in an Acid Medium." Metals 11, no. 5: 817.
This review aims to understand the environmental impact that tailings produce on the land and marine ecosystem. Issues related to flora, fauna, and the environment are revised. In the first instance, the origin of the treatment and disposal of marine mining waste in Chile and other countries is studied. The importance of tailings’ valuable elements is analyzed through mineralogy, chemical composition, and oceanographic interactions. Several tailings’ treatments seek to recover valuable minerals and mitigate environmental impacts through leaching, bioleaching, and flotation methods. The analysis was complemented with the particular legislative framework for every country, highlighting those with formal regulations for the disposal of tailings in a marine environment. The available registry on flora and fauna affected by the discharge of toxic metals is explored. As a study case, the “Playa Verde” project is detailed, which recovers copper from marine tailings, and uses phytoremediation to neutralize toxic metals. Countries must regularize the disposal of marine tailings due to the significant impact on the marine ecosystem. The implementation of new technologies is necessary to recover valuable elements and reduce mining waste.
Freddy Rodríguez; Carlos Moraga; Jonathan Castillo; Edelmira Gálvez; Pedro Robles; Norman Toro. Submarine Tailings in Chile—A Review. Metals 2021, 11, 780 .
AMA StyleFreddy Rodríguez, Carlos Moraga, Jonathan Castillo, Edelmira Gálvez, Pedro Robles, Norman Toro. Submarine Tailings in Chile—A Review. Metals. 2021; 11 (5):780.
Chicago/Turabian StyleFreddy Rodríguez; Carlos Moraga; Jonathan Castillo; Edelmira Gálvez; Pedro Robles; Norman Toro. 2021. "Submarine Tailings in Chile—A Review." Metals 11, no. 5: 780.
Determining the uniaxial compressive strength of intact rock is the primary objective of a geomechanical project, and a reliable estimate in the early phases saves time and costs for more sophisticated laboratory tests. The problem is knowing which of the correlations between the resistance to uniaxial compression and point load index are reliable, those that cover one or several types of rock (depending on the type of statistical adjustment). In this work, they were evaluated with respect to limestone and travertine from experimental results, and the statistical models of the scale effect of the point load index were determined, and the uniaxial compressive strength being estimated from correlations reported in literature. The limestone model was ascending (strength increases as diameter increases), while the travertine model was descending (strength decreases as diameter increases), obtaining similar exponents for the scale effect equations modeled from the uniaxial compressive strength and point load index in both cases.
Solange Contreras; Manuel Saldaña; Norman Toro; Ignacio Pérez-Rey; Manuel González; Javier González. Scale Effect and Correlation between Uniaxial Compressive Strength and Point Load Index for Limestone and Travertine. Applied Sciences 2021, 11, 3672 .
AMA StyleSolange Contreras, Manuel Saldaña, Norman Toro, Ignacio Pérez-Rey, Manuel González, Javier González. Scale Effect and Correlation between Uniaxial Compressive Strength and Point Load Index for Limestone and Travertine. Applied Sciences. 2021; 11 (8):3672.
Chicago/Turabian StyleSolange Contreras; Manuel Saldaña; Norman Toro; Ignacio Pérez-Rey; Manuel González; Javier González. 2021. "Scale Effect and Correlation between Uniaxial Compressive Strength and Point Load Index for Limestone and Travertine." Applied Sciences 11, no. 8: 3672.
Magnesium and magnesium-derived alloys are critical to a diverse set of industries, due to their particular physicochemical properties, including biocompatibility, low density, mechanical dampening, and hydrogen-storage capacity. Moreover, the magnesium compounds are themselves vital in agricultural, pharmaceutical, construction and broad industrial applications. Leaching is a critical step in the recovery of magnesium from magnesium-bearing ore, and the most common leaching agents are organic and inorganic acids, as well and ammonium salts, the efficacy of which depends on the mineral feed. Organic acids are used with minerals having fast leaching kinetics; these acids have less dissolving power but are more selective and are less destructive to the equipment. In contrast, inorganic acids have more dissolving power and are easier to source. However, the inorganic acids are less selective and cause more damage to equipment, as they complicate pH control. The objective of this work has been to review studies on the kinetics of magnesium mineral extraction, and the effects of critical parameters depending on the feed mineral and the reagents. Several works are presented on the leaching kinetics of natural and calcined dolomite and magnesite, and hydrated magnesium salts, as well as ferromagnesian silicates and serpentinite, which are important sources of magnesium. It has been shown that the most influential parameters in dissolving magnesium are the temperature and the reagent concentration, which have a direct effect on magnesium extraction rates. However, there is a point at which increases in these parameters result in more impurities and/or have insignificant effects on magnesium dissolution. Particle size has an inverse relationship to magnesium extraction since the area of contact with the leaching surface is greater with smaller particles. The effect of the agitation speed is insignificant with magnesite feeds, given that the process is controlled largely by surface chemical reactions, while the leaching kinetics of serpentinite is controlled by diffusion through the product layer.
Yessica González; Alessandro Navarra; Ricardo I. Jeldres; Norman Toro. Hydrometallurgical processing of magnesium minerals – A review. Hydrometallurgy 2021, 201, 105573 .
AMA StyleYessica González, Alessandro Navarra, Ricardo I. Jeldres, Norman Toro. Hydrometallurgical processing of magnesium minerals – A review. Hydrometallurgy. 2021; 201 ():105573.
Chicago/Turabian StyleYessica González; Alessandro Navarra; Ricardo I. Jeldres; Norman Toro. 2021. "Hydrometallurgical processing of magnesium minerals – A review." Hydrometallurgy 201, no. : 105573.
The accelerated growth in global demand for Manganese coincides with the continuing depletion of high-grade ores on the earth's surface. This element is essential for diverse markets such as steel production, dietary additives, fertilizers, cells, fine chemicals, and some chemical reagents. Interestingly, there are large mineral reserves in the ocean's depths, where marine nodules are an attractive option due to their high manganese content (between 16 and 24%). The dissolution of MnO2 from manganese nodules needs a reducing agent. Iron is a feasible alternative with a low cost and can even be recycled from scrap or industrial waste like smelting slag, tailings, or scrap steel. This paper provides a comprehensive review of Manganese acid-reducing processes from marine nodules using different iron-reducing agents that include FeS2, Fe2+, Fe0, Fe2O3, and Fe3O4. Fe0 has displayed the best performance in terms of dissolution kinetics and Mn extraction. This review further confers the chemistry and reactions involved in the reductive leaching and stresses the critical parameters that could be considered for optimization. In this sense, the concentration of reducing agent and temperature are highlighted as the most influential, making other parameters (e.g., particle size, stirring speed, acid concentration, and leaching time) almost irrelevant. Finally, it is concluded that the best way to extract Mn from marine nodules is to reuse steel scraps, working with high Fe0/MnO2 ratios (2/1), low concentrations of sulfuric acid (0.1 mol/L), and short times (5 min), achieving extractions of 90%.
Norman Toro; Freddy Rodríguez; Anyelo Rojas; Pedro Robles; Yousef Ghorbani. Leaching manganese nodules with iron-reducing agents – A critical review. Minerals Engineering 2021, 163, 106748 .
AMA StyleNorman Toro, Freddy Rodríguez, Anyelo Rojas, Pedro Robles, Yousef Ghorbani. Leaching manganese nodules with iron-reducing agents – A critical review. Minerals Engineering. 2021; 163 ():106748.
Chicago/Turabian StyleNorman Toro; Freddy Rodríguez; Anyelo Rojas; Pedro Robles; Yousef Ghorbani. 2021. "Leaching manganese nodules with iron-reducing agents – A critical review." Minerals Engineering 163, no. : 106748.
Structural and morphological properties of hydronium-potassium jarosite microstructures were investigated in this work, and their electrical properties were evaluated. All the microstructures were synthesized at a very low temperature of 70 °C with a reduced reaction time of 3 h. An increase in the pH from 0.8 to 2.1 decreased the particle sizes from 3 µm to 200 nm and an increase in the aging time from zero, three, and seven days resulted in semispherical, spherical, and euhedral jarosite structures, respectively. The Rietveld analysis also confirmed that the amount of hydronium substitution by potassium in the cationic site increased with an increase in pH. The percentages of hydronium jarosite (JH)/potassium jarosite (JK) for pH values of 0.8, 1.1, and 2.1 were 77.72/22.29%, 82.44/17.56%, and 89.98/10.02%, respectively. Microstructures obtained in this work were tested as alternative anode materials and the voltage measured using these electrodes made with hydronium-potassium jarosite microstructures and graphite ranged from 0.89 to 1.36 V. The results obtained in this work show that with reduced particle size and euhedral morphology obtained, modified jarosite microstructures can be used as anode materials for improving the lifetime of lithium-ion batteries.
Elías Hernández-Lazcano; E. Cerecedo-Sáenz; J. Hernández-Ávila; Norman Toro; T. V. K. Karthik; D. Mendoza-Anaya; M. E. Fernández-García; V. Rodríguez-Lugo; E. Salinas-Rodríguez. Synthesis of Hydronium-Potassium Jarosites: The Effect of pH and Aging Time on Their Structural, Morphological, and Electrical Properties. Minerals 2021, 11, 80 .
AMA StyleElías Hernández-Lazcano, E. Cerecedo-Sáenz, J. Hernández-Ávila, Norman Toro, T. V. K. Karthik, D. Mendoza-Anaya, M. E. Fernández-García, V. Rodríguez-Lugo, E. Salinas-Rodríguez. Synthesis of Hydronium-Potassium Jarosites: The Effect of pH and Aging Time on Their Structural, Morphological, and Electrical Properties. Minerals. 2021; 11 (1):80.
Chicago/Turabian StyleElías Hernández-Lazcano; E. Cerecedo-Sáenz; J. Hernández-Ávila; Norman Toro; T. V. K. Karthik; D. Mendoza-Anaya; M. E. Fernández-García; V. Rodríguez-Lugo; E. Salinas-Rodríguez. 2021. "Synthesis of Hydronium-Potassium Jarosites: The Effect of pH and Aging Time on Their Structural, Morphological, and Electrical Properties." Minerals 11, no. 1: 80.
Sensors and process control systems are essential for process automation and optimization. Many sectors have adapted to the Industry 4.0 paradigm, but copper smelters remain hesitant to implement these technologies without appropriate justification, as many critical functions remain subject to ground operator experience. Recent experiments and industrial trials using radiometric optoelectronic data acquisition, coupled with advanced quantitative methods and expert systems, have successfully distinguished between mineral species in reactive vessels with high classification rates. These experiments demonstrate the increasing potential for the online monitoring of the state of a charge in pyrometallurgical furnaces, allowing data-driven adjustments to critical operational parameters. However, the justification to implement an innovative control system requires a quantitative framework that is conducive to multiphase engineering projects. This paper presents a unified quantitative framework for copper and nickel-copper smelters, which integrates thermochemical modeling into discrete event simulation and is, indeed, able to simulate smelters, with and without a proposed set of sensors, thus quantifying the benefit of these sensors. Sample computations are presented, which are based on the authors’ experiences in smelter reengineering projects.
Alessandro Navarra; Ryan Wilson; Roberto Parra; Norman Toro; Andrés Ross; Jean-Christophe Nave; Phillip J. Mackey. Quantitative Methods to Support Data Acquisition Modernization within Copper Smelters. Processes 2020, 8, 1478 .
AMA StyleAlessandro Navarra, Ryan Wilson, Roberto Parra, Norman Toro, Andrés Ross, Jean-Christophe Nave, Phillip J. Mackey. Quantitative Methods to Support Data Acquisition Modernization within Copper Smelters. Processes. 2020; 8 (11):1478.
Chicago/Turabian StyleAlessandro Navarra; Ryan Wilson; Roberto Parra; Norman Toro; Andrés Ross; Jean-Christophe Nave; Phillip J. Mackey. 2020. "Quantitative Methods to Support Data Acquisition Modernization within Copper Smelters." Processes 8, no. 11: 1478.
Chalcocite (Cu2S) has the fastest kinetics of dissolution of Cu in chlorinated media of all copper sulfide minerals. Chalcocite has been identified as having economic interest due to its abundance, although the water necessary for its dissolution is scarce in many regions. In this work, the replacement of fresh water by sea water or by reject brine with high chloride content from desalination plants is analyzed. Additionally, the effect of adding MnO2 from available manganese nodules in vast quantities at the bottom of the sea is studied. Reject brine shows better results than sea water, and the addition of MnO2 to the brine significantly increases the kinetics of chalcocite dissolution in a short time. H2SO4 concentration is found to be irrelevant when working at high concentrations of chloride and MnO2. The best results, 71% Cu extractions in 48 h, are obtained for reject brine, 100 mg of MnO2 per 200 g of mineral and H2SO4 0.5 mol/L. The results are expected to contribute to a sustainable process of dissolution of chalcocite by using the reject brine from desalination plants.
David Torres; Emilio Trigueros; Pedro Robles; Williams Leiva; Ricardo Jeldres; Pedro Toledo; Norman Toro. Leaching of Pure Chalcocite with Reject Brine and MnO2 from Manganese Nodules. Metals 2020, 10, 1426 .
AMA StyleDavid Torres, Emilio Trigueros, Pedro Robles, Williams Leiva, Ricardo Jeldres, Pedro Toledo, Norman Toro. Leaching of Pure Chalcocite with Reject Brine and MnO2 from Manganese Nodules. Metals. 2020; 10 (11):1426.
Chicago/Turabian StyleDavid Torres; Emilio Trigueros; Pedro Robles; Williams Leiva; Ricardo Jeldres; Pedro Toledo; Norman Toro. 2020. "Leaching of Pure Chalcocite with Reject Brine and MnO2 from Manganese Nodules." Metals 10, no. 11: 1426.
The scarcity of water resources for mining activities drives the search for new low-quality water sources such as well-water and seawater. Seawater was found to be a promising alternative, but it may pose significant operational challenges, for example, when it needs to be recovered from the tailings in thickening stages for subsequent recycling. This is mainly explained by the high saline environment and colloidal magnesium precipitates that are generated at highly alkaline conditions. In this work, we use molecular dynamics (MD) simulations to understand the affinity of the flocculant with colloidal magnesium precipitates and the main minerals that make up a mining tailing such as quartz and kaolinite. The results are contrasted with the in-situ characterization of aggregates through the Focused Beam Reflectance Measurement (FBRM). Through X-ray diffraction, it was found that the magnesium precipitates are mainly composed of brucite crystals. The MD results allowed to explain the experimental results, mainly when solid magnesium precipitates appear at high pH, where the flocculant loses its effectiveness sharply. This is related to the undesired association among the flocculant with brucite. The adsorption is mainly carried out by the interaction between the deprotonated oxygen from the acrylic group of the polymer and the oxygen from the hydroxide of the brucite surface. There is also a significant contribution of hydrogen bonding between nitrogen from the acrylamide group and oxygen from the hydroxide.
Gonzalo R. Quezada; Matías Jeldres; Norman Toro; Pedro Robles; Pedro G. Toledo; Ricardo I. Jeldres. Understanding the flocculation mechanism of quartz and kaolinite with polyacrylamide in seawater: A molecular dynamics approach. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2020, 608, 125576 .
AMA StyleGonzalo R. Quezada, Matías Jeldres, Norman Toro, Pedro Robles, Pedro G. Toledo, Ricardo I. Jeldres. Understanding the flocculation mechanism of quartz and kaolinite with polyacrylamide in seawater: A molecular dynamics approach. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2020; 608 ():125576.
Chicago/Turabian StyleGonzalo R. Quezada; Matías Jeldres; Norman Toro; Pedro Robles; Pedro G. Toledo; Ricardo I. Jeldres. 2020. "Understanding the flocculation mechanism of quartz and kaolinite with polyacrylamide in seawater: A molecular dynamics approach." Colloids and Surfaces A: Physicochemical and Engineering Aspects 608, no. : 125576.
A population balance model described the flocculation of clay-based mining tailings in treated seawater with reduced magnesium content. For the treatment, 0.06 M of lime was added to the liquor, generating solid magnesium complexes that were subsequently removed by vacuum filtration. Magnesium content varied between 10–1440 ppm when mixing raw seawater with treated seawater. The aggregate size was analysed by the Focused Beam Reflectance Measurement (FBRM) technology. The model follows the dynamics of the aggregation-rupture and it provides a good approximation to the temporal evolution. A decrease in collision efficiency was implemented as an indicator of the polymer depletion, describing the size reduction. Lower magnesium content makes larger aggregates with a higher fractal dimension, but an increase in the concentration of clays reduces both the size of aggregates and the fractal dimension, indicating more open and porous structures, with higher permeability to the passage of fluid. The model efficiently illustrates the experimental data, with R-square (R2) greater than 0.9 and Goodness of Fit (GoF) greater than 95% in most cases, wherein the fitting parameters allowed for analysing the impact of magnesium and clays on the collision efficiency, collision frequency, and fragmentation rate. The model is predictive with few parameters, and it is potentially a powerful tool for water management optimisation.
Gonzalo R. Quezada; Matías Jeldres; Pedro Robles; Norman Toro; David Torres; Ricardo I. Jeldres. Improving the Flocculation Performance of Clay-Based Tailings in Seawater: A Population Balance Modelling Approach. Minerals 2020, 10, 782 .
AMA StyleGonzalo R. Quezada, Matías Jeldres, Pedro Robles, Norman Toro, David Torres, Ricardo I. Jeldres. Improving the Flocculation Performance of Clay-Based Tailings in Seawater: A Population Balance Modelling Approach. Minerals. 2020; 10 (9):782.
Chicago/Turabian StyleGonzalo R. Quezada; Matías Jeldres; Pedro Robles; Norman Toro; David Torres; Ricardo I. Jeldres. 2020. "Improving the Flocculation Performance of Clay-Based Tailings in Seawater: A Population Balance Modelling Approach." Minerals 10, no. 9: 782.
Global warming is one of the most significant issues of today. Carbon dioxide is the primary contributor to climate change, and is mainly formed by the energy sector; thus, it is imperative to expand the total decarbonisation of this industry. Another global concern is the high demand and low supply of critical metals due to the constant growth of technological advances. These elements are essential for the manufacturing of advanced technology, green technology, and emerging industries. Currently, there is global tension and unrest over how the critical metals market is developing, with one example regarding China, which has an apparent monopoly on the mining, refining, and technical expertise associated with rare earth elements. China currently provides approximately 90% of the production of rare earth elements, causing conflicts with the European Union, the USA, and Japan due to their dependence on these raw materials. Another controversial case is the production of cobalt in the Democratic Republic of the Congo, which dominates in the global production (60% of the world’s production of Co). Despite this, the Democratic Republic of the Congo is one of the poorest countries in the world. The constant depletion of high-grade minerals from the Earth's surface forces the search for new alternative sources of the critical metals. The abundance of minerals within the sea is of relevance, with large deposits of marine nodules, ferromanganese crusts, and massive polymetallic sulphides. These are of great interest to the mining industry, as it is estimated that the largest reserves of various critical metals are found on the seabed, in addition to the largest reserves of cobalt, nickel, and manganese, and a considerable amount of rare earth elements. The exploitation of mineral resources from the seabed by the company Deep Sea Mining Finance Limited (DSMF) is currently being developed, which might promote the expansion of this market throughout the world. The wealth of minerals in the seabed may be a solution to the shortage of critical metals in the market, may decrease political tensions between countries worldwide, and may promote the large-scale deployment of renewable energy.
Norman Toro; Pedro Robles; Ricardo I. Jeldres. Seabed mineral resources, an alternative for the future of renewable energy: A critical review. Ore Geology Reviews 2020, 126, 103699 .
AMA StyleNorman Toro, Pedro Robles, Ricardo I. Jeldres. Seabed mineral resources, an alternative for the future of renewable energy: A critical review. Ore Geology Reviews. 2020; 126 ():103699.
Chicago/Turabian StyleNorman Toro; Pedro Robles; Ricardo I. Jeldres. 2020. "Seabed mineral resources, an alternative for the future of renewable energy: A critical review." Ore Geology Reviews 126, no. : 103699.
Given the active growth of emerging technology industries, it has become essential to have large quantities of critical metals to meet the current demand. In the Chilean mining industry, there is a depletion of high-grade mineral ores, and there is hence a need to increase production levels in the copper industry and diversify its market by extracting other elements. One of the strategies is to foster the production of lithium batteries, but the manufacture requires reserves of cobalt (Co) and manganese (Mn). Currently, Co reserves are not being exploited in Chile, and Mn production is almost negligible. This is due to the apparent shortage of high-grade ores on the land surface of the country. Given this scenario, the seabed manganese nodules are presented as a good alternative due to their high average grades of Co and Mn, which in turn would allow the growth of strategic value-added industries including lithium battery production. Chile’s current environmental regulations prevent the exploitation of marine resources. However, given technological advances worldwide, both in collection mechanisms and extractive processes, in addition to the needs generated from the future strategic plans, leads us to think about a project to exploit manganese nodules locally.
Norman Toro; Ricardo I. Jeldres; Javier A. Órdenes; Pedro Robles; Alessandro Navarra. Manganese Nodules in Chile, an Alternative for the Production of Co and Mn in the Future—A Review. Minerals 2020, 10, 674 .
AMA StyleNorman Toro, Ricardo I. Jeldres, Javier A. Órdenes, Pedro Robles, Alessandro Navarra. Manganese Nodules in Chile, an Alternative for the Production of Co and Mn in the Future—A Review. Minerals. 2020; 10 (8):674.
Chicago/Turabian StyleNorman Toro; Ricardo I. Jeldres; Javier A. Órdenes; Pedro Robles; Alessandro Navarra. 2020. "Manganese Nodules in Chile, an Alternative for the Production of Co and Mn in the Future—A Review." Minerals 10, no. 8: 674.
In the rock mechanics and rock engineering field, the strength parameter considered to characterize the rock is the uniaxial compressive strength (UCS). It is usually determined in the laboratory through a few statistically representative numbers of specimens, with a recommended minimum of five. The UCS can also be estimated from rock index properties, such as the effective porosity, density, and P-wave velocity. In the case of a porous rock such as travertine, the random distribution of voids inside the test specimen (not detectable in the density-porosity test, but in the compressive strength test) causes large variations on the UCS value, which were found in the range of 62 MPa for this rock. This fact complicates a sufficiently accurate determination of experimental results, also affecting the estimations based on regression analyses. Aiming to solve this problem, statistical analysis, and machine learning models (artificial neural network) was developed to generate a reliable predictive model, through which the best results for a multiple regression model between uniaxial compressive strength (UCS), P-wave velocity and porosity were obtained.
Manuel Saldaña; Javier González; Ignacio Pérez-Rey; Matías Jeldres; Norman Toro. Applying Statistical Analysis and Machine Learning for Modeling the UCS from P-Wave Velocity, Density and Porosity on Dry Travertine. Applied Sciences 2020, 10, 4565 .
AMA StyleManuel Saldaña, Javier González, Ignacio Pérez-Rey, Matías Jeldres, Norman Toro. Applying Statistical Analysis and Machine Learning for Modeling the UCS from P-Wave Velocity, Density and Porosity on Dry Travertine. Applied Sciences. 2020; 10 (13):4565.
Chicago/Turabian StyleManuel Saldaña; Javier González; Ignacio Pérez-Rey; Matías Jeldres; Norman Toro. 2020. "Applying Statistical Analysis and Machine Learning for Modeling the UCS from P-Wave Velocity, Density and Porosity on Dry Travertine." Applied Sciences 10, no. 13: 4565.
Manuel Saldaña; Christian Escobar; Edelmira Galvez; David Torres; Norman Toro. Mapping of the Perception of Theft Crimes from Analysis of Newspaper Articles Online. 2020 15th Iberian Conference on Information Systems and Technologies (CISTI) 2020, 1 .
AMA StyleManuel Saldaña, Christian Escobar, Edelmira Galvez, David Torres, Norman Toro. Mapping of the Perception of Theft Crimes from Analysis of Newspaper Articles Online. 2020 15th Iberian Conference on Information Systems and Technologies (CISTI). 2020; ():1.
Chicago/Turabian StyleManuel Saldaña; Christian Escobar; Edelmira Galvez; David Torres; Norman Toro. 2020. "Mapping of the Perception of Theft Crimes from Analysis of Newspaper Articles Online." 2020 15th Iberian Conference on Information Systems and Technologies (CISTI) , no. : 1.
A less harmful approach for the environment regarding chalcopyrite concentrate leaching, using seawater/brine and caliche’s salts as a source of chloride and nitrate ions, was investigated. Different variables were evaluated: sulfuric acid concentration, sodium nitrate concentration, chloride concentration, source of water (distilled water, seawater, and brine), temperature, concentrate sample type, nitrate source (analytical grade and industrial salt), and pre-treatment methods in order to obtain maximum copper extraction. All tests were performed at moderate temperatures (≤45 °C) and atmospheric pressure. The leaching system using distilled water, seawater, and brine base media resulted in copper extraction of 70.9%, 90.6%, and 86.6% respectively. The leaching media, with a concentration of 20 g/L Cl−, obtained a maximum Cu extraction of 93.5%. An increase in the concentration of H2SO4 and NaNO3 from 0.5 to 0.7 M, led to an increase in the copper extraction. The use of an industrial salt compared to the analytical salt did not show great variations in the percentage of extraction achieved, which would be a good and cost effective alternative. The increase in temperature from 25 to 45 °C showed a great effect on the copper leaching (of 60% until 90.6%, respectively). The pre-treatment is suggested to increase copper extraction from 60.0% to 71.4%.
Pía Hernández; Alexis Dorador; Monserrat Martínez; Norman Toro; Jonathan Castillo; Yousef Ghorbani. Use of Seawater/Brine and Caliche’s Salts as Clean and Environmentally Friendly Sources of Chloride and Nitrate Ions for Chalcopyrite Concentrate Leaching. Minerals 2020, 10, 477 .
AMA StylePía Hernández, Alexis Dorador, Monserrat Martínez, Norman Toro, Jonathan Castillo, Yousef Ghorbani. Use of Seawater/Brine and Caliche’s Salts as Clean and Environmentally Friendly Sources of Chloride and Nitrate Ions for Chalcopyrite Concentrate Leaching. Minerals. 2020; 10 (5):477.
Chicago/Turabian StylePía Hernández; Alexis Dorador; Monserrat Martínez; Norman Toro; Jonathan Castillo; Yousef Ghorbani. 2020. "Use of Seawater/Brine and Caliche’s Salts as Clean and Environmentally Friendly Sources of Chloride and Nitrate Ions for Chalcopyrite Concentrate Leaching." Minerals 10, no. 5: 477.
Black coppers are mineraloids with a high content of Cu and Mn. These have an amorphous crystalline structure that makes them refractory to conventional leaching processes. For this reason, these mineral resources are not incorporated in industrial leaching heap processes and are taken to dumps. In the present study, an agglomerate pretreatment process incorporating NaCl is evaluated, and a curing stage, followed by acid-reducing leaching for Cu and Mn dissolution from a high-grade black copper mineral. For this, an experimental design was developed both to evaluate the impact of the dependent variables on the response, to generate analytical models that represent the copper and manganese recoveries under the set of sampled conditions. The models indicate that the curing time and the NaCl concentration have a primary effect on the recovery of both elements. In contrast, the optimization model suggests that the optimal operating levels are reached at relatively high levels of time (>130 h) and of NaCl concentration (>22 kg/t).
Manuel Saldaña; Edelmira Gálvez; Ricardo I. Jeldres; Catalina Díaz; Pedro Robles; Manish Kumar Sinha; Norman Toro. Optimization of Cu and Mn Dissolution from Black Coppers by Means of an Agglomerate and Curing Pretreatment. Metals 2020, 10, 657 .
AMA StyleManuel Saldaña, Edelmira Gálvez, Ricardo I. Jeldres, Catalina Díaz, Pedro Robles, Manish Kumar Sinha, Norman Toro. Optimization of Cu and Mn Dissolution from Black Coppers by Means of an Agglomerate and Curing Pretreatment. Metals. 2020; 10 (5):657.
Chicago/Turabian StyleManuel Saldaña; Edelmira Gálvez; Ricardo I. Jeldres; Catalina Díaz; Pedro Robles; Manish Kumar Sinha; Norman Toro. 2020. "Optimization of Cu and Mn Dissolution from Black Coppers by Means of an Agglomerate and Curing Pretreatment." Metals 10, no. 5: 657.
In this study, weak acid in the curing and leaching stages of copper ore was incorporated, and we analyzed its effect on the dissolution of copper and final impurities. The weak acid corresponds to a wastewater effluent from sulfuric acid plants produced in the gas treatment of copper smelting processes. This effluent is basically water with high acidity (pH-value low at 1), which contains several toxic elements and some valuable metals. The results indicated that there is no positive or negative effect on the incorporation of the weak acid in the curing stage, while the case of the leaching stage is favored. Toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) toxicity tests were performed on the solid leaching residues, determining that they accomplish the stability ranges of the impurities (Pb, Cd, Hg, Cr, Ba, Se, As, and Ag).
Giselle Araya; Norman Toro; Jonathan Castillo; Danny Guzmán; Alexis Guzmán; Pía Hernández; Ricardo I. Jeldres; Rossana Sepúlveda. Leaching of Oxide Copper Ores by Addition of Weak Acid from Copper Smelters. Metals 2020, 10, 627 .
AMA StyleGiselle Araya, Norman Toro, Jonathan Castillo, Danny Guzmán, Alexis Guzmán, Pía Hernández, Ricardo I. Jeldres, Rossana Sepúlveda. Leaching of Oxide Copper Ores by Addition of Weak Acid from Copper Smelters. Metals. 2020; 10 (5):627.
Chicago/Turabian StyleGiselle Araya; Norman Toro; Jonathan Castillo; Danny Guzmán; Alexis Guzmán; Pía Hernández; Ricardo I. Jeldres; Rossana Sepúlveda. 2020. "Leaching of Oxide Copper Ores by Addition of Weak Acid from Copper Smelters." Metals 10, no. 5: 627.