Examinando por Autor "Reyes-Bozo, Lorenzo"

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    Adsorption of biosolids and their main components on chalcopyrite, molybdenite and pyrite: Zeta potential and FTIR spectroscopy studies
    (Elsevier Ltd, 2015-07) Reyes-Bozo, Lorenzo; Higueras, Pablo; Godoy-Faúndez, Alex; Salazar, José Luis; Valdés-González, Héctor; Wolf-Sepúlveda, Germán; Herrera-Urbina, Ronaldo; Escudey, Mauricio; Vyhmeister, Eduardo
    Zeta potential measurements were used to assess the electrokinetic characteristics of chalcopyrite, molybdenite and pyrite in the presence of biosolids and their main components (humic acids, glucose and serum albumin) as well as a commercial collector (Aero 6697). Fourier transform infrared spectroscopy (FTIR) was then used to gain a deeper understanding of the interaction of these compounds with these sulfide minerals. It aims to achieve a better understanding of the surface chemistry of sulfide-water interfaces that improve froth flotation at industrial scale in the step of copper sulfide ore concentration. Zeta potential results show that hydrogen and hydroxide ions are potential determining ions for each sulfide mineral studied. The addition of 50 g/t biosolids or all the other chemicals used in this investigation shift the isoelectric point of chalcopyrite. Under the same conditions, only humic acid significantly affects the zeta potential of molybdenite, making it more negative in the pH range investigated, and shifting its isoelectric point about 6 pH units. These compounds seem to have a poor affinity with pyrite surfaces because their zeta potential is slightly modified. FTIR spectroscopy characterization shows that biosolids and their main components can interact with chalcopyrite, molydenite and pyrite surfaces through a complex mechanism involving chemical or physical linkages. The results reported here seem to indicate that biosolids may be used as new environment-friendly froth flotation agents to concentrate copper and molybdenum sulfide minerals. © 2015 Elsevier Ltd.
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    Container stacking revenue management system: A fuzzy-based strategy for valparaiso port
    (Universidad Nacional de Colombia, 2015) Valdés-González, Héctor; Reyes-Bozo, Lorenzo; Vyhmeister, Eduardo; Salazar, José Luis; Sepúlveda, Juan Pedro; Mos Ca-Arestizábal, Marco
    This article presents an intelligent system for container stacking based on fuzzy logic. The method establishes a defined criterion for accepting or rejecting in real time an entry request to the stacking areas of the port in Valparaiso, Chile. A case study based on expert knowledge illustrates the proposed method with real data. First, the optimum solution is determined for a problem of maximization of entries, based on historical records from the traffic and information center of Valparaiso Port. Second, this solution is used to establish a strategy for making “the best possible decisions.” The combination of the optimization and the fuzzy results (which consider the type of cargo, prices, and capacity) is performed at two levels. First, the optimization results are used as feed for the fuzzy system to determinate a ratio of future acceptances. Second, the optimization results are compared to the fuzzy system results in order to estimate a parameter to establish the minimal percentage value for accepting a request. As a result, a proper use of the stacking area is achieved, which results in an increase of profits and revenue management. © The author; licensee Universidad Nacional de Colombia.
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    Viability analysis for use of methane obtained from green hydrogen as a reducing agent in copper smelters
    (Elsevier B.V., 2021-12) Reyes-Bozo, Lorenzo; Salazar, José Luis; Valdés-González, Héctor; Sandoval-Yáñez, Claudia; Vivanco-Soffia, María Elena; Bilartello, Luna; Poblete, Valentina; Soto, Antonella; Urrea, María José
    This study explores the use of green hydrogen as a flexible and environmentally-friendly energy vector in copper mining. The refining of copper sulphide ores involves several stages, such as comminution, froth flotation and smelting. The latter produces a higher concentration of copper through chemical transformations of copper sulphide ores. Reducing agents such as coal, coke, ferrosilicon and diesel are typically used in this step, but these reagents unfortunately have a considerable environmental footprint. The main goal of this work was therefore to perform a techno-economic analysis for methane production from the use of green hydrogen as a reducing agent for the smelting stage. The methodology involved the evaluation of the project based on a Net Present Value calculation and a sensitivity analysis of the main parameters which were performed using Oracle Crystal Ball software. The main results show a Net Present Value of 5.459 M USD and an 11.8-year pay-back. Multiparametric analysis shows that NPV is positive with 97.32% of confidence and that the main variable affecting the NPV is the methane price (contribution to variance of 97,8%). We conclude that the use of green hydrogen in copper smelting is a technically viable solution with economic and environmental benefits. The economic evaluation could be further improved with the incorporation of the heat and oxygen by-product, further reducing the CO2 emission.