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Mellado M.E.,Research Center Cientifico Tecnologico Para la Mineria | Galvez E.D.,Catolica del Norte University | Cisternas L.A.,University of Antofagasta
International Journal of Mineral Processing | Year: 2011

In this paper we present some considerations on the computation of optimal flow rates for the heap leaching process of solid reactants from porous pellets. We use a model already published by authors, which is suitable in applications where the scale-up is necessary. This approach allows to obtain better flow rates. Novelty of this approach is the simple form of the models and the easy way to compute good flow rates as used in actual operations in industry, for instance, alternate flows. We propose, also, an exponentially decreasing flow rate which is optimal from the mathematical point of view and the model being used. Due to the model simplicity, they can be used without mathematical complexities. We present a brief sensibility analysis to identify important operation variables that are relevant to change usual constant flow rates of lixiviant agents. Through simple optimization and case studies, we find better flow rate to minimize the acid and water consumed in the process under consideration. © 2011 Elsevier B.V. All rights reserved. Source


Meier L.,University of the Frontier | Perez R.,University of the Frontier | Azocar L.,University of the Frontier | Rivas M.,Research Center Cientifico Tecnologico Para la Mineria | And 2 more authors.
Biomass and Bioenergy | Year: 2015

The use of photosynthetic CO2 reduction capacity of microalgae can be used for biogas upgrading. Such process would convert CO2 contained in the biogas into microalgal biomass, generating two products: upgraded biogas and biomass. Growth rate of Nannochloropsis gaditana was determined in atmospheres containing different levels of CH4 and CO2. Results showed no effect of CH4 rich atmosphere over microalgal development. CO2 inhibition was observed only when microalgae culture was exposed to atmospheres containing 9% of CO2. Direct contact of the biogas and the microalgal culture is not a feasible way to upgrade biogas, due to oxygen desorption to the gas phase. A two-stage process, involving a photobioreactor connected with a gas/liquid mass transfer unit showed to be an efficient way to remove CO2 from the biogas, keeping low levels of oxygen in the upgraded biogas. © 2014 Elsevier Ltd. Source


Ghorbani Y.,University of Antofagasta | Kuan S.H.,University Tunku Abdul Rahman | Kuan S.H.,Research Center Cientifico Tecnologico Para la Mineria
International Journal of Mining, Reclamation and Environment | Year: 2016

Chile is the principal producer of copper with a total of 5.8 million tonnes fine copper production in 2013. Chilean mining industry currently faces a projected increase in waste production, depleting water resources in the arid mining regions of the north and a lack of fossil fuel energy sources. In this study, a review of the historical background of environmental practices in Chile is presented, focused between 1970 and 2010. A review of the current state of sustainable development, comprising energy, water, stakeholder participation, environmental impacts and institutional decentralisation in the mining industry is presented. © 2016 Taylor & Francis Source


Lucay F.,Research Center Cientifico Tecnologico Para la Mineria | Lucay F.,Catolica del Norte University | Mellado M.E.,Research Center Cientifico Tecnologico Para la Mineria | Cisternas L.A.,University of Antofagasta | And 3 more authors.
International Journal of Mineral Processing | Year: 2012

Several methods for the design of separation circuits have been presented in the literature. These methodologies can be classified as those that use either heuristics or mathematical optimization techniques. However, none of these methods is currently used in industry. This is, the former is very simple to incorporate the complexities of the problem and the latter requires that the designer has more specialized training. In this work, we use sensitivity analysis to analyze and design separation circuits. We study the effect of each stage on the general circuit by identifying the relationships between recovery at each stage and global recovery of the circuit. Based on these results, we propose a novel methodology to analyze and design separation circuits. This new method is a hybrid because it uses mathematical analysis and the designer's experience. An example is provided for flotation separation in copper mining. © 2012 Elsevier B.V. All rights reserved. Source


Mellado M.E.,Research Center Cientifico Tecnologico Para la Mineria | Casanova M.P.,University of Concepcion | Cisternas L.A.,Research Center Cientifico Tecnologico Para la Mineria | Cisternas L.A.,University of Antofagasta | And 2 more authors.
Computers and Chemical Engineering | Year: 2011

In this paper we present analytical models suitable for scaling up the heap leaching process of solid reactants from porous pellets. The models are based on first order ordinary differential equations together with some constitutive relations derived from models based on ordinary and partial differential equations and other relations based on insight. The models are suitable for applications in which the scale-up is neccesary. This approach allows to obtain accurate solutions for actual industry heap leaching operations. Novelty of this approach is the simple form of the models and its accuracy as compared with more complex models. Due to the models simplicity, they can be used for analysis, design, control and optimization of heap leaching processes without mathematical complexities. The models include the effect of heap height, particle sizes, flow rates, and several operation-design variables. Finally, some numerical experiments which confirm our theory are presented. © 2010 Elsevier Ltd. Source

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