Gold Sterile Ore Acid Generation Evaluation, San Juan Argentina

One of the problems that mining represents in relation to the natural watercourses is the possible formation of what we call acid mine drainage, which consists in the emission or formation of water effluents of great acidity, usually rich in sulfate and with variable contents in heavy metals. The drainage mentioned is developed from the metal sulfide and sulfate leaching. Researches about the creation of acid drainage suggest that the formation of these depends directly on various factors: primary mineralogy (neutralizer sulfides and minerals), water presence (whether), oxygen diffusion, grain size, microbiological interaction (bacterium), among others. To study these variables and to relate them with geological factors, static (Acid-Base Accounting) and dynamic (Humidity Cell) tests have been developed, among others. The mentioned tests are applied to a case of a gold deposit situated in the Province of San Juan, which is currently very argued because of its mining activity due to its leaching process. In the sterile mineral obtained from the process, kinetics tests were carried out in humidity cells to simulate the natural oxidation of the primary mineral samples. In the obtained leaching, pH values closer to neutrality and a limited solution metal presence were detected, indicating the neutralization ability due to the carbonates ores presence.Fil: Bazan Brizuela, Vanesa Lucia. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sarquis, Pedro Edgardo. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; ArgentinaFil: Brandaleze, Elena. Universidad Tecnológica Nacional. Facultad Regional San Nicolás; Argentin

Argentinean copper concentrates: structural aspects and thermal behaviour

In Argentina, there are many sources of copper concentrates. Some of them are currently in operation, while others are in the exploration stage. All copper concentrates produced are exported to other countries for copper refinement and to create various finished products. It is desirable that in the near future, these copper concentrates be processed in an Argentinean industrial plant. The aim of this paper was to present the results of a characterisation study carried out on five different copper concentrate samples. The thermal decomposition of the copper concentrates was determined by differential thermal analysis and thermogravimetry (DTA TG). The information was correlated with the chemical composition and the mineralogical phases of the samples identified by X-ray diffraction. A melting test at temperatures of up to 1300˚C was performed to complete the study of the concentrate’s behaviour during heating. After the test, all of the samples were observed by light and electronic scanning microscopy to identify the different phases generated under high-temperature conditions.Fil: Bazan Brizuela, Vanesa Lucia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Juan; ArgentinaFil: Brandaleze, Elena. Universidad Tecnológica Nacional. Facultad Regional San Nicolás. Centro para el Desarrollo Tecnológico de Materiales; ArgentinaFil: Santini, Leandro Matias. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional San Nicolás. Centro para el Desarrollo Tecnológico de Materiales; ArgentinaFil: Sarquis, Pedro Edgardo. Universidad Nacional de San Juan; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Coagulación de finos en la flotación de la fluorita

Fluorite, a valuable mineral in the metallurgical industry, can be found together with silicates, carbonates and oxides in ore deposits. Commercial concentrates with more than 95 % of CaF2 are obtained processing the mineral in flotation plants and using oleic acid as fluorite collector. Depressor reagents such as sodium silicate, tannin and sodium carbonate are commonly employed to allow the oleic acid selective performance. These reagents cause a dispersant effect separating the solid-liquid solution on tailing plants. Fine particles in the recovered water enter the circuit and affect the flotation efficiency. The effect of coagulant ions was studied as a method to clarify the returned water. The problem of the presence of these ions is related to its reactions with the collector by the formation of compounds and possibly on the selectivity. Variable quantities of Al3+, Fe3+ and Ca2+ ions were added to the flotation to evaluate its effect on the fluorite recovery, in the selectivity and in solids content in recirculation water. Results show that some ions fail to improve water quality and are detrimental to flotation. On the contrary, some ions contribute to reduce fine content in suspension. Therefore, although there is a recovery reduction, such effect can be counteracted increasing the collector consumption a little.La fluorita es un mineral de mucha importancia en la industria metalúrgica. Se presenta acompañada de silicatos, carbonatos y óxidos. Para la obtención de concentrados comerciales, más de 95 % de CaF2, el mineral se procesa en plantas de flotación donde se usa ácido oleico como colector de la fluorita. Para que el ácido oleico actúe electivamente es común el uso de reactivos depresores: silicato de sodio, tanino y carbonato de sodio. Estos agentes tienen un efecto dispersante que se evidencia en la separación de sólido-llquido sobre las colas de las plantas. El agua recuperada contiene finos que al ingresar al circuito afectan notoriamente la eficiencia de la flotación. Se estudió el efecto de iones coagulantes para clarificar el agua de retorno. El problema de estos iones está relacionado con sus reacciones con el colector por la fonnación de compuestos y, posiblemente, sobre la selectividad. Se agregaron cantidades variables de iones Al3+, Fe3++ y Ca2+ y se evaluó la recuperación de fluorita, la selectividad y en el contenido de sólidos en el agua de los efluentes. Los resultados muestran que algunos iones no solamente no mejoran la calidad del agua sino que además son perjudiciales en la flotación. Otros, por el contrarío, contribuyen a reducir el contenido de finos en suspensión. Por lo tanto, y si bien hay una pérdida en la recuperación, este efecto se puede contrarrestar con un pequeño aumento en el consumo de colectorFil: Sarquis, Pedro Edgardo. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; ArgentinaFil: Gonzalez, Mercedes Isabel. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Moyano, Silvia Adriana. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; ArgentinaFil: Bazan Brizuela, Vanesa Lucia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentin

Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe

Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity

Evaluation of the use of slag from the mining of au and ag as a replacement of the sand in cement mortars

To the benefit of gold minerals, extraction processes are generally applied by carrying out cyanidation and subsequent smelting to obtain dore thereby generating slags. The properties of the slag obtained vary depending on the origin of the mineral and on the type of load flux used. However, in the Pyrometallurgy literature the reuse of the slag generated at this stage of the process has not been analyzed.Therefore, the present research is focused on studying the characteristics of slags of minerals from San Juan province in Argentina, obtained at a laboratory scale, analyzing the possibility of recycling in case they present appropriate physical and chemical properties.Slag characterization (description) was made by using different techniques such as: chemical analysis with acid digestion and subsequent determination with ICP, structural study by applying optical microscopy techniques in white light mode and polarized light. Observation and semi-quantitative chemical analysis of the samples is completed by using an ESEM scanning electron microscope and analysis with the EDS technique. Finally, analyses about the physical properties obtained are carried out for subsequent use of the slag as cementFil: Bazan Brizuela, Vanesa Lucia. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Brandaleze, Elena. Universidad Tecnológica Nacional. Facultad Regional San Nicolás; ArgentinaFil: Sarquis, Pedro Edgardo. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentin

Developments in gold and silver recovery through flotation in processing of gold ore slags

El objetivo del presente trabajo es recuperar y mejorar la obtención de oro y plata, presentes en escorias de fundición, mediante diferentes procesos mineralurgicos aplicables en menas de oro. La escoria se concentró en una centrífuga tipo Knelson, obteniéndose dos concentrados (C1 y C2) y un estéril (T1). Para mejorar la recuperación, se realizaron tres series de pruebas de flotación Rougher sobre el estéril T1. Las variables utilizadas fueron: tamaño de partícula, uso de colectores (xantantos, di-monotiofosfato) y tiempos variables de flotación. Se concluye que la recuperación de Au y Ag, aplicando concentración por gravedad (centrífuga Knelson) son del 42.0 % y 13.7 % respectivamente. La recuperación de Au se mejora en un 87.7% a través de la flotación del estéril de la separación centrífuga y en un 47.4 % para la Ag. Siendo las condiciones óptimas: granulometría a 200 mallas, colectores: PAX (15.8 g/t); F-C5439 (18.75 g/t), espumante MIBC (12.5 g/t) y un tiempo de flotación de 8.5 minutos.The aim of this work is to recover and improve the extraction of gold and silver present in smelting slags through various minerallurgical processes applicable in gold ores. The slag was concentrated in a Knelson type centrifuge, two concentrates (C1 and C2 and a tailing T1) being obtained. In order to improve the recovery, three series of rougher flotation tests were conducted on the tailing T1. The variables analyzed were: particle size, type of collectors (xanthates, di-monothiophosphate) and flotation time. It was deduced that by applying gravity concentration, the recovery of Au and Ag (Knelson centrifuge) is 42.0% and 13.7%, respectively. Au recovery is improved by 87.7% through the flotation of the centrifuge separation tailings, whereas that for Ag is 47.4%. The optimum conditions were: particle size 200#, collectors: PAX (15.8 g/t), F-C5439 (18.75 g/t), MIBC frother (12.5g/t) and 8.5 minutes of flotation time.Fil: Hidalgo, Natalia. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Diaz, Andrea Alejandra. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bazan Brizuela, Vanesa Lucia. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sarquis, Pedro Edgardo. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin