Use of the System S2o3 (2-) -O2 for the Leaching of Precious Metals Contained in a Mineral From Molango in the State of Hidalgo, Mexico

The newer tendencies of research, related with the leaching of precious metals, involves the use of non toxic reagents that allows the leaching of a mineral of sedimentary origin using the system S2 - O3 2- - O2. Prior to thisprocess, the mineral was characterized by Scanning Electron Microscopy (SEM) in conjunction with Energy Dispersive Spectrometry of X – rays (EDS), X- ray mapping. Finally, the chemical composition was executed by Inductively Coupled Plasma Spectrometry (ICP). According to the results obtained, it was possible to determine that the mineral studied has adequate contents of gold, palladium, silver, and platinum. And after the leaching process, it could be possible to leach the gold and palladium that it contains, getting recoveries of 90% and 85 %, respectively. In the case of silver, a redissolution or precipitation could occur during the first minutes of reaction

Use of Porous no Metallic Minerals to Remove Heavy Metals, Precious Metals and Rare Earths, by Cationic Exchange

This chapter is related with the preliminary study of some non-metallic minerals to evaluate their cationic exchange capacity, to remove heavy and precious metals, as well as rare earths elements. The minerals and materials used to execute the ion metals removal were bentonite, phosphorite, and diatomite. The chapter shows the physicochemical behavior of all these minerals, which were used to remove the mentioned elements from solutions coming from ore leaching. It was found that in all cases, the removal of heavy and precious metals, as well as rare earths elements reached over 90%. Although, there were minimal differences in efficiency for all minerals used (bentonite, phosphorite, and diatomite), it could be pointed that the phosphorite has the best results going from 99.43% of removal of Gd, to 99.95–100% for the case of Ce, Nd, La, Yb, Eu, Er, Sm, Tb, Ge, Pd, Pt, and Au

Leaching chalcopyrite with High MnO2 and chloride concentrations

Most copper minerals are found as sulfides, with chalcopyrite being the most abundant. However; this ore is refractory to conventional hydrometallurgical methods, so it has been historically exploited through froth flotation, followed by smelting operations. This implies that the processing involves polluting activities, either by the formation of tailings dams and the emission of large amounts of SO2 into the atmosphere. Given the increasing environmental restrictions, it is necessary to consider new processing strategies, which are compatible with the environment, and, if feasible, combine the reuse of industrial waste. In the present research, the dissolution of pure chalcopyrite was studied considering the use of MnO2 and wastewater with a high chloride content. Fine particles (20 _m) generated an increase in extraction of copper from the mineral. Besides, it was discovered that working at high temperatures (80 _C); the large concentrations of MnO2 become irrelevant. The biggest copper extractions of this work (71%) were achieved when operating at 80 _C; particle size of 47 + 38 _m, MnO2/CuFeS2 ratio of 5/1, and 1 mol/L of H2SO4.The authors are grateful for the contribution of the Scientific Equipment Unit-MAINI of the Universidad Católica del Norte for facilitating the chemical analysis of the solutions. Pedro Robles thanks the Pontificia Universidad Católica de Valparaíso for the support provided. Also, we thanks Conicyt Fondecyt 11171036 and Centro CRHIAM Project Conicyt/Fondap/15130015

Relación entre la resistencia a antibióticos y la producción de biofilm de aislados de Staphylococcus aureus provenientes de mastitis bovina

The objective was to analyze the relationship between the antibiotic-resistance profile and the biofilm formation of S. aureus isolates from bovine mastitis. Thirty (30) isolates of S. aureus from cases of subclinical mastitis in dairy farms in semi-intensive production and backyard production systems, located in the states of Guanajuato and Michoacán, Mexico, were analyzed. An antibiogram was performed by the Kirbi-Bauer disc-diffusion method. Biofilm formation was determined by the violet crystal staining method. For the evaluation of antibiotic resistance genes and biofilm formation, genomic DNA was obtained from a colony for the identification of the genes: blaZ, mecA, tetK, tetM, gyrA and gyrB, and icaA and icaD. The results showed that 100 % of the isolates were resistant to penicillin and dicloxacillin, followed by cefotaxime (86.6 %), ampicillin and cephalotin (83.3 %) and ceftazidime (80.0 %), while a 36.6 % resistance to oxacillin was observed. It was identified that all isolates of S. aureus had the ability to form biofilm with a range between 20 to 98 %. It was also observed that isolates with a high multi-resistance presented a greater formation of biofilm, establishing a significant positive correlation. In conclusion, S. aureus isolates from bovine mastitis presented high levels of antibiotic resistance; as well as an important biofilm-forming capacity, demonstrating the existence of a positive correlation between these two factors.El objetivo fue analizar la relación entre el perfil de resistencia a antibióticos y la formación de biofilm de aislados de S. aureus provenientes de mastitis bovina. Se analizaron 30 aislados de S. aureus procedentes de casos de mastitis subclínica en granjas lecheras en sistemas de producción semi-intensivo y de traspatio ubicadas en los estados de Guanajuato y Michoacán, México. Se realizó un antibiograma por el método de difusión en disco Kirbi Bauer. La formación de biofilm se determinó por el método de tinción con cristal violeta. Para la evaluación de genes de resistencia a antibióticos y de formación de biofilm se obtuvo ADN genómico de una colonia para la identificación de los genes: blaZ, mecA, tetK, tetM, gyrA y gyrB, y icaA e icaD. Los resultados mostraron que el 100 % de los aislados fueron resistentes a penicilina  y dicloxacilina, seguidos  por cefotaxima  (86.6 %),  ampicilina y cefalotina (83.3 %) y ceftazidima (80.0 %), mientras que se observó un 36.6 % de resistencia a oxacilina. Se identificó que todos los aislados de S. aureus presentaron la capacidad de formar biofilm con un rango del 20 a 98 %. Se observó además que los aislados con una multirresistencia elevada presentaron una mayor formación de biofilm; estableciéndose una correlación positiva significativa. En conclusión, los aislados de S. aureus provenientes de mastitis bovina presentaron elevados niveles de resistencia a antibióticos; así como una importante capacidad formadora de biofilm, demostrando la existencia de una correlación positiva entre estos dos factores

Internet of Things for Sustainable Mining

The sustainable mining Internet of Things deals with the applications of IoT technology to the coupled needs of sustainable recovery of metals and a healthy environment for a thriving planet. In this chapter, the IoT architecture and technology is presented to support development of a digital mining platform emphasizing the exploration of rock–fluid–environment interactions to develop extraction methods with maximum economic benefit, while maintaining and preserving both water quantity and quality, soil, and, ultimately, human health. New perspectives are provided for IoT applications in developing new mineral resources, improved management of tailings, monitoring and mitigating contamination from mining. Moreover, tools to assess the environmental and social impacts of mining including the demands on dwindling freshwater resources. The cutting-edge technologies that could be leveraged to develop the state-of-the-art sustainable mining IoT paradigm are also discussed

Use of Alternative Water Resources in Copper Leaching Processes in Chilean Mining Industry—A Review

Due to the significant growth of the world population, the accelerated growth of economic industries in various countries, and improved living conditions, freshwater consumption has increased dramatically and is currently under critical pressure. Its good use and rationing are essential. Even though mining is an industry that consumes much less water than other industries, such as agriculture, surrounding communities are constantly questioned. This occurs mainly because mining deposits are generally found in arid areas where freshwater is scarce, forcing government authorities to regulate water use in mining processes more severely. Faced with this scenario, the mining industry has innovated the use of seawater and wastewater from processes for its production processes. In addition, various projects are under development to construct desalination plants and water impulsion systems of the sea; therefore, it is expected that seawater and/or wastewater in mining will continue to grow in the coming years. Among the main challenges faced in the use of these water resources in mining is: (i) the close relationship that exists between the use of seawater and energy consumption, transferring the problem of water scarcity to a problem of energy cost overruns; (ii) generation of greater integration between the use of water and sustainable energy; and (iii) brine management is economically expensive and technically challenging and, therefore, most desalination plants discharge untreated brine directly into the sea, causing an environmental impact. On the other hand, regarding the use of these water resources in leaching processes, there are very positive results for the dissolution of copper from sulfide minerals, where the wastewater from desalination plants presents better results than seawater due to its higher concentration of chloride ions, allowing it to work at higher redox potential values in order to increase copper dissolution. This manuscript is a bibliographic review in which finally, it is concluded that it is feasible to incorporate wastewater from water desalination plants in heap leaching processes for copper sulfide ores, as long as the cost of transfer from water desalination plants to mining sites can be supported

Kinetics of Iron Leaching from Kaolinitic Clay, Using Phosphoric Acid

Kaolin is important because it has many applications in the paper, paint-coating, functional filler, extender and pigment industries. This material needs to be bleached by iron leaching to be useful for these applications because this element can be the principal cause of its undesirable coloration. In this work, the kinetics of leaching of iron contained in kaolin clays from the community of Agua Blanca Iturbide, Hidalgo, Mexico, was studied. The leaching experiments were carried out using phosphoric acid as the reagent of leaching for the iron dissolution process. Temperature, acid concentration, and particle size were investigated to determine the most important kinetics parameters during iron leaching. It was determined that the rate of iron dissolution increases with increasing of phosphoric acid concentration, the temperature, and decreased particle size of clay. Data obtained showed that iron dissolution from kaolin clay is due to the diffusion of iron through the product layer. The results revealed that the activation energy of the process was 10.18 kJ·mol−1

Leaching of Silver and Gold Contained in a Sedimentary Ore, Using Sodium Thiosulfate; A Preliminary Kinetic Study

Some sedimentary minerals have attractive contents of gold and silver, like a sedimentary exhalative ore available in the eastern of Hidalgo in Mexico. The gold and silver contained represent an interesting opportunity for processing by non-toxic and aggressive leaching reagents like thiosulfate. The preliminary kinetic study indicated that the leaching process was poorly affected by temperature and thiosulfate concentration. The reaction order was −0.61 for Ag, considering a thiosulfate concentration between 200–500 mol·m−3, while, for Au, it was −0.09 for a concentration range between 32–320 mol·m–3. By varying the pH 7–10, it was found that the reaction order was n = 5.03 for Ag, while, for Au, the value was n = 0.94, considering pH 9.5–11. The activation energy obtained during the silver leaching process was 3.15 kJ·mol−1 (298–328 K), which was indicative of a diffusive control of the process. On the other hand, during gold leaching, the activation energy obtained was of 36.44 kJ·mol−1, which was indicative that this process was mixed controlled process, first at low temperatures by diffusive control (298–313 K) and then by chemical control (318–323 K)

Reducing-Effect of Chloride for the Dissolution of Black Copper

Oxidized black copper ores are known for their difficulty in dissolving their components of interest through conventional methods. This is due to its non-crystalline and amorphous structure. Among these minerals, copper pitch and copper wad are of great interest because of their considerable concentrations of copper and manganese. Currently, these minerals are not incorporated into the extraction circuits or left untreated, whether in stock, leach pads, or waste. For the recovery of its main elements of interest (Cu and Mn), it is necessary to use reducing agents that dissolve the present MnO2, while allowing the recovery of Cu. In this research, the results for the dissolution of Mn and Cu from a black copper mineral are exposed, evaluating the reducing effect of NaCl for MnO2 through pre-treatment of agglomerate and curing, and subsequently leaching in standard condition with the use of a reducing agent (Fe2+). High concentrations of chloride in the agglomerate process and prolonged curing times would favor the reduction of MnO2, increasing the dissolution of Mn, while the addition of NaCl did not benefit Cu extractions. Under standard conditions, low Mn extractions were obtained, while in an acid-reducing medium, a significant dissolution of MnO2 was achieved, which supports the removal of Cu