Innovative Solutions for Seawater Use in Mining Operations

This chapter reviews the use of seawater in the mining industry in Chile, especially from the perspective of the current situation and the innovative proposals for its sustainable use. This chapter describes the current use of seawater, with and without desalting, in the mining sector in Chile, as well as its future projection. Descriptions are given for the current desalination systems, mining operations currently using seawater and new projects, current water distribution systems, seawater applications in hydrometallurgy and minerals concentration, their environmental impacts, and difficulties in adapting processes in case of use of seawater without desalination. This is complemented by a description of mining in Chile, its importance for Chile and its relationship to the global mining. Finally, problems and opportunities are identified. A second aspect considered in this chapter is the innovative solutions that are being investigated to solve some of the problems indicated above, including integrated seawater distribution systems, seawater biodesalination, partial desalination using carbon dioxide, adaptation of process to the use of seawater without desalination, and uses of discard brines from reverse osmosis plants

Solution strategies to the stochastic design of mineral flotation plants

The aim of this study is two-fold: first, to analyze the effect of stochastic uncertainty in the design of flotation circuits and second, to analyze different strategies for the solution of a two-stage stochastic problem applied to a copper flotation circuit. The paper begins by introducing a stochastic optimization problem whose aim is to find the best configuration of superstructure, equipment design and operational conditions, such as residence time and stream flows. Variability is considered in the copper price and ore grade. This variability is represented by scenarios with their respective probability of occurrence. The resulting optimization problem is a two-stage stochastic mixed integer nonlinear program (TS-MINLP), which can be extremely challenging to solve. For this reason, several solvers for this problem are compared and two stochastic programming methodologies are applied. The combination of these techniques allows the production of high quality solutions and an analysis of their sensitivity to epistemic uncertainty. The results show that the stochastic problem gives better designs because it allows operational parameters to adapt to the uncertainty of the parameters. The results also show that the flotation circuit structure can vary with the feed grade and copper price. The sensitivity analysis shows small to moderate variability with epistemically uncertain parameters

Bioprospecting of Ureolytic Bacteria From Laguna Salada for Biomineralization Applications

The processes of biomineralization, mediated by ureolytic bacteria, possess a wide range of technological applications, such as the formation of biocements and remediation of water and soil environments. For this reason, the bioprospecting of new ureolytic bacteria is interesting for its application to these technologies, particularly for water treatment. This study demonstrates the isolation, selection, and identification of halotolerant ureolytic bacteria from Laguna Salada (inland from Atacama Desert) and the evaluation of their ability to precipitate calcium carbonate crystals in freshwater in the presence of calcium ions, as well as the ability to induce the precipitation of crystals from different ions present in seawater. Twenty-four halotolerant ureolytic bacteria whose molecular identification gives between 99 and 100% identity with species of the genus Bacillus, Porphyrobacter, Pseudomonas, Salinivibrio, and Halomonas were isolated. When cultivated in freshwater, urea, and calcium chloride, all species are able to biomineralize calcium carbonate in different concentrations. In seawater, the strains that biomineralize the highest concentration of calcium carbonate correspond to Bacillus subtilis and Halomonas sp. SEM–EDX and XRD analyses determined that both bacteria induce the formation of 9–33% halite (NaCl), 31–66% monohydrocalcite (CaCO3 × H2O), and 24–27% struvite (MgNH4PO4 × 6H2O). Additionally, B.subtilis induces the formation of 7% anhydrite (CaSO4). In seawater, B.subtilis and Halomonas sp. were able to precipitate both calcium (96–97%) and magnesium (63–67%) ions over 14 days of testing. Ion removal assays with B.subtilis immobilized in beads indicate a direct relationship between the urea concentration and a greater removal of ions with similar rates to free cells. These results demonstrate that the biomineralization mediated by bacterial urea hydrolysis is feasible in both freshwater and seawater, and we propose its application as a new technology in improving water quality for industrial uses

Editorial for Special Issue “Modeling, Design and Optimization of Multiphase Systems in Minerals Processing”

The exploitation of mining resources has been fundamental for the development of humanity since before industrialization [...

Modeling, Design and Optimization of Multiphase Systems in Minerals Processing

Mineral processing deals with complex particle systems with two-, three- and more phases. The modeling and understanding of these systems are a challenge for research groups and a need for the industrial sector. This Special Issue aims to present new advances, methodologies, applications, and case studies of computer-aided analysis applied to multiphase systems in mineral processing. This includes aspects such as modeling, design, operation, optimization, uncertainty analysis, among other topics. The special issue contains a review article and eleven articles that cover different methodologies of modeling, design, optimization, and analysis in problems of adsorption, leaching, flotation, and magnetic separation, among others. Consequently, the topics covered are of interest to readers from academia and industry

Editorial for Special Issue “Modeling, Design, and Optimization of Multiphase Systems in Minerals Processing, Volume II”

The manuscripts published in the 2019 Special Issue “Modeling, Design, and Optimization of Multiphase Systems in Minerals Processing” [...

The Marmara Sea region: Seismic behaviour in time and the likelihood of another large earthquake near Istanbul (Turkey)

The North Anatolian Fault (NAF) extends for about 1500 km from Karliova to the east, to the Egean Sea in the west. The Marmara region, located near the western end of the NAF, is a tectonically active zone characterized by the transition between a strike slip stress regime and an extensional one in the Aegean Sea. Microseismic studies performed around the Marmara Sea in 1995 [Tectonophysics 316, 2000, 1], and just before the 1999 Izmit Earthquake (Bull. Seism. Soc. Am. 92, 2002a, 361; J. Seismol. 6, 2002b, 287) permitted the analysis of the evolution of seismicity connected to this destructive earthquake and its sequels. Several observations indicate that the aftershock distribution fits well the EW orientation of the NAF, but the ruptures are not simple and linear as a first glance would suggest. Instead they are segmented in at least five pieces as shown by the slip variation and aftershock clusters, showing complexity at different scales ( Bull. Seism. Soc. Am. 92, 2002a, 361). There is still a gap, across the northern border of the Marmara Sea that has not ruptured, and this is the only sector that did not break on the NAF since the 1939 great Erzincan earthquake. Will it rupture as a whole with a large magnitude earthquake, or by segments with smaller magnitude events? The Hurst analysis of the overall behaviour of the seismicity in the Marmara region since historical times shows that if a large earthquake occurs in the near future, it might break the complete gap. The Hurst character of the time variation of seismicity is persistent with H = 0.82. The aftershocks of the 1999 Izmit earthquake can be analyzed by using the Hurst method, showing an exceptionally high persistent memory

Biomineralization Mediated by Ureolytic Bacteria Applied to Water Treatment: A Review

The formation of minerals such as calcite and struvite through the hydrolysis of urea catalyzed by ureolytic bacteria is a simple and easy way to control mechanisms, which has been extensively explored with promising applications in various areas such as the improvement of cement and sandy materials. This review presents the detailed mechanism of the biominerals production by ureolytic bacteria and its applications to the wastewater, groundwater and seawater treatment. In addition, an interesting application is the use of these ureolytic bacteria in the removal of heavy metals and rare earths from groundwater, the removal of calcium and recovery of phosphate from wastewater, and its potential use as a tool for partial biodesalination of seawater and saline aquifers. Finally, we discuss the benefits of using biomineralization processes in water treatment as well as the challenges to be solved in order to reach a successful commercialization of this technology