Papers by Luis A Cisternas
Minerals, 2017
Caliche is a mineral exploited in northern Chile, from which iodine and Nitrate salts (saltpeter)... more Caliche is a mineral exploited in northern Chile, from which iodine and Nitrate salts (saltpeter) are obtained. This ore is the most important source of iodine in the world and is processed mainly by heap leaching using water as a leaching agent. Heap leaching of caliche ore is carried out by the stacking of ROM (Run-Of-Mine) material, where the particle size distribution covers a wide range, from a few millimeters up to several decimeters, even diameters about 1 m. During the leaching, the multiple soluble species of caliche, which can reach total fractions larger than 40%, are dissolved at different rates, mainly controlled by their solubilities. When it occurs and unlike most other leachable ores, the particle size diminishes. The leaching modeling of several soluble species of caliche has been recently addressed; however, one of the main assumptions is the idealization that the heap is composed of particles of the same size. The present work aims to complement the previously formulated phenomenological models for caliche ore leaching, through a model that considers the simultaneous dissolution of two species from caliche with three different particle sizes. These two water-soluble species have different solubilities and dissolution rates and the conceptual model considers that both species are dissolved at the particle surface. When the most soluble species is being depleted, the particle collapses, leaving a remaining fraction of the less soluble species together with insoluble material. The less soluble species is now being dissolved from the collapsed material. This article also includes the experimental verification of the conceptual model using data obtained from column leaching tests conducted for this purpose, focusing on the dissolution of two soluble species: Nitrate and Magnesium.
Minerals, 2020
The combined use of the Radial Basis Function Network (RBFN) model with pretreated seawater by bi... more The combined use of the Radial Basis Function Network (RBFN) model with pretreated seawater by biomineralization (BSw) was investigated as an approach to improve copper tailings flocculation for mining purposes. The RBFN was used to set the optimal ranges of Ca2+ and Mg2+ concentration at different Ph in artificial seawater to optimize the performance of the mine tailings sedimentation process. The RBFN was developed by considering Ca2+ and Mg2+ concentration as well as pH as input variables, and mine tailings settling rate (Sr) and residual water turbidity (T) as output variables. The optimal ranges of Ca2+ and Mg2+ concentration were found, respectively: (i) 169–338 and 0–130 mg·L−1 at pH 9.3; (ii) 0–21 and 400–741 mg·L–1 at pH 10.5; (iii) 377–418 and 703–849 mg·L−1 at pH 11.5. The settling performance predicted by the RBFN was compared with that measured in raw seawater (Sw), chemically pretreated seawater (CHSw), BSw, and tap water (Tw). The results highlighted that the RBFN mod...
Minerals, 2020
Modeling the global markets is complicated due to the existence of uncertainty in the information... more Modeling the global markets is complicated due to the existence of uncertainty in the information available. In addition, the lithium supply chain presents a complex network due to interconnections that it presents and the interdependencies among its elements. This complex supply chain has one large market, electric vehicles (EVs). EV production is increasing the global demand for lithium; in terms of the lithium supply chain, an EV requires lithium-ion batteries, and lithium-ion batteries require lithium carbonate and lithium hydroxide. Realistically, the mass balance in the global lithium supply chain involves more elements and more markets, and together with the assortment of databases in the literature, make the modeling through deterministic models difficult. Modeling the global supply chain under uncertainty could facilitate an assessment of the lithium supply chain between production and demand, and therefore could help to determine the distribution of materials for identifyi...
Desalination, 2017
Abstract Antofagasta (Chile) is an arid region, and the climate is strongly influenced by the Ata... more Abstract Antofagasta (Chile) is an arid region, and the climate is strongly influenced by the Atacama Desert, with few sources of fresh water. The pressure to use non-conventional water sources has boosted the construction of numerous desalination plants. High concentrations of secondary ions as calcium and magnesium cause problems in reverse osmosis plants and in other industries such as copper mining and cooling system. Biomineralization process based on hydrolysis of urea has been described in a wide variety of bacterial species with diverse applications. The selection of ureolytic halotolerant bacteria from Atacama Salar and their ability to precipitate calcium and magnesium crystals in seawater is described. Besides crystal structure and morphology were determined by electron microscopy analysis and X-ray diffraction. When assessing the mineral precipitate ability, Rhodococcus erythropolis precipitates a ~ 95% soluble calcium and 8% magnesium. The analysis of crystals showed that correspond to ~ 12.69% monohydrocalcite, ~ 30.72% struvite and ~ 56.59% halite. These results demonstrate that the biomineralization by ureolytic bacteria in seawater has great potential for its application as a pretreatment to improve water quality for industrial processes.
This study presents a procedure for the design or improvement of mineral flotation circuits, base... more This study presents a procedure for the design or improvement of mineral flotation circuits, based on a mathematical programming model with disjunctive equations. The procedure is characterized by: 1. The development of hierarchized superstructures, such that the first level represents certain separation tasks. The second level represents circuits of equipment needed to carry out the tasks. 2. A MILP mathematical
This work presents a method for the design of flotation circuits in minerals processing. The prob... more This work presents a method for the design of flotation circuits in minerals processing. The problem is represented by several superstructures. The first superstructure represents separation tasks (STS), which includes: feed processing superstructure (FPS), concentrate processing superstructure (CPS), and tail processing superstructure (TPS). The FPS commonly use a single stage, i.e., rougher. The CPS represents the circuit needed to carry out the cleaner task, and the TPS represents the circuit needed to carry out the scavenger task. These superstructures are flow networks between several separation stages. In each separation stage two kinds of cells are allowed, bank and column. In several streams in the CPS and TPS, the incorporation of regrind mills is also included. The optimal selection of the circuit is made with an appropriate objective function, upon which the values of the operational and structural variables may be determined. The problem is formulated using disjunctive programming, which is converted to a MILP problem. The model includes mass balance, equipment models, operational conditions, and logic relationship. The approach is illustrated for a copper concentration plant.
Chemical Engineering Research and Design, 2007
IEEE Transactions on Power Delivery, 2004
Russian Journal of Inorganic Chemistry
Ingenieria Quimica, 2001
Se analiza la integracion energetica entre el sistema de evaporacion quimica y las corrientes de ... more Se analiza la integracion energetica entre el sistema de evaporacion quimica y las corrientes de procesos ajenas al sistema de evaporacion
Minerals & Metallurgical Processing, 2018
Froth flotation processes are carried out in flotation cells that are grouped into banks, and the... more Froth flotation processes are carried out in flotation cells that are grouped into banks, and these banks are interconnected, forming a flotation circuit. A literature review shows the existence of papers related to flotation circuit design based on mathematical programming. However, due to the complexity of solving the mathematical model in most of the work, it is considered that a small number of species is present in the feed to the circuit, which differs from practice. In addition, simple bank models are generally used. This paper presents a methodology for designing mineral concentration circuits that overcomes the problems mentioned. It allows the use of more suitable cell or bank models and the inclusion of several species. The methodology is based on two phases. The first phase identifies the set of optimal structures using discrete values of stage recoveries, solving several mixed integer linear programming (MILP) problems. In the second phase, the optimal design for each o...
Applied Energy
Abstract The tailing storage facility is the largest water sink in most mines. An incorrect manag... more Abstract The tailing storage facility is the largest water sink in most mines. An incorrect management of water content in mine tailings can become a threat to their stability, and consequently, their environmental safety. Also, water reuse and recycling are plausible options to mining companies for reasons pertaining to water scarcity. Dewatering technologies for tailings, desalination and water transport are energy intensive. Proper handling of mine tailings and water supply management can considerably improve the water-energy nexus. This article evaluates the water-energy nexus in copper mining companies using a water reduction model focused on mine tailing facilities and water supply to the mine site to find the trade-offs between water and energy. The originality of this work consists in the application of a real options approach, enabling to increase the flexibility of decision-making thanks to quantitative analysis. This approach deploys the Monte Carlo simulation to perform sensitivity and uncertainty analysis to evaluate every cost component of water management strategy. Results show that if seawater is the primary source of raw water to the mining plant, water transport represents the largest cost due to the use of energy. So, improving the reuse of water by using dewatering technologies will improve the water-energy nexus, by improving energy consumption. Even though the costs of these technologies are elevated because they are energy-intensive, reduction of water use requirements in the mine will reduce the cost of its treatment and transport.
Journal of Environmental Management
Minerals Engineering
Abstract Mineral processing usually utilizes multi-unit separations because complete separation i... more Abstract Mineral processing usually utilizes multi-unit separations because complete separation is seldom achieved in one unit. The analysis and design of these circuits have been an active area of research in the exploration for improvements in mineral processing. Linear circuit analysis (LCA) has been proposed as a simple tool for the analysis of mineral processing circuits. Clearly, LCA is a tool with several advantages, but it does have its limitations and disadvantages. This paper presents an analysis of some limitations and disadvantages of LCA. The results show that LCA must be used carefully because the application of LCA can introduce errors and incomplete analysis.
Desalination
Abstract The use of non-desalinated seawater for mining purposes is not recommendable because of ... more Abstract The use of non-desalinated seawater for mining purposes is not recommendable because of the high salinity and the presence of some ions, that is, Ca2+ and Mg2+, that can hamper the mineral tailings separation process besides being responsible for scaling formation in pipelines and equipment. To remove these ions from seawater, a novel treatment involving a biomineralization process was tested using a fluidized bed bioreactor (FBB) filled with immobilized beads of the halotolerant ureolytic strain Bacillus subtilis LN8B. The FBB was operated in batch mode according to a sequence of six cycles of eight days. The highest efficiency in removing Ca2+ and Mg2+ occurred in the first cycle for both ions, achieving the removal rate of ~100% by day four for Ca2+ and ~80% by day six for Mg2+, respectively. Precipitates from FBB were mainly composed of ~70.2% of hydromagnesite, and ~17.8% of aragonite. Furthermore, the efficiency of biologically pretreated seawater (BSw) was evaluated as mineral tailings sedimentation medium and compared with three types of water: (i) tap water (Tw); (ii) seawater (Sw); and (iii) distilled water, (Dw). The results showed that the settling velocity in BSw was the highest (i.e., 6.23 ± 0.48 m h−1).
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Papers by Luis A Cisternas