Development of A Hydrometallurgical Process for the Extraction of Cobalt, Manganese, and Nickel from Acid Mine Drainage Treatment Byproduct

Critical minerals (CMs) are defined as crucial elements for the country\u27s economy due to the development of new cutting-edge applications and the risk of an eventual disruption in their supply chain. The unique chemical and physical properties of the CMs have made these elements decisive in the growth of industries such as telecommunications, army, medicine, Aerospace, etc. In 2022, the US Geological Survey established a list of 50 CMs, including manganese, cobalt, nickel, aluminum, magnesium, and others. Of the total of CMs, 26 are 100% imported from outside the United States (Venditti, 2022). Driven by the ever-increasing demand for critical minerals (CMs) and the need to diversify their supply chains, extensive research efforts have been devoted to extracting CMs from various secondary sources, such as fossil fuel (coal ash and refuse), mining tailings, refuse piles, water produced by oil and gas industry, electronic waste (E-waste), and acid mine drainage (AMD), among which acid mine drainage and its treatment byproducts proved to be a viable source. Characterization studies of different AMD and sludge materials indicate the occurrence of CMs containing rare earth elements (REEs), cobalt, manganese, nickel, zinc, aluminum, magnesium, etc. In this context, our research aimed to develop an optimized hydrometallurgical process for extracting multiple individual CM concentrates, including cobalt, manganese, and nickel, from acid mine drainage treatment byproducts. The feedstock used throughout is an REE solvent extraction raffinate loaded with cobalt, manganese, and nickel, with grades corresponding to 38.3 mg/L, 370.7 mg/L, and 69.4 mg/L, respectively, as well as impurity metals such as 3643.1 mg/L of aluminum, 2161.4 mg/L of magnesium, 224.1 mg/L of calcium, and 159.2 mg/L of iron. A hydrometallurgical process developed at the laboratory scale consists of an initial sodium hydroxide precipitation using 2M NaOH until reaching a pH value equal to 5. The approach targeted the upstream removal of impurities such as aluminum and iron and was established by performing stagewise precipitation from an initial pH of 2 to a final value of 12. The optimum pH values were identified by taking samples at each pH setpoint and analyzing the tradeoff between CM recovery and impurity removal. Afterward, a solution with a higher concentration of CMs and lower impurity content was subjected to a new precipitation process with 2M NaOH until reaching pH 10 to generate a precipitated product rich in CMs. The precipitated solids obtained at the pH range of 5 to 10 were treated to separate cobalt and nickel from manganese. The procedure carried out in this stage was a nitric acid washing (HNO3), which was performed under controlled conditions of temperature, time, volume, etc. Two products were obtained in this stage: a dissolved solution with an extractable concentration of cobalt and nickel (393 mg/L and 619.9 mg/L, respectively) and a solid product with a manganese purity of 47.9% by weight. To continue separating cobalt and nickel from remaining impurities, such as magnesium, a new stagewise precipitation with sodium sulfide (Na2S) at 1M was performed to determine the separation feasibility of different elements in the solution. At this stage, three separation steps were determined to generate three solid products: the solid precipitated at the pH range of 1-5 with 5.1 wt.% of cobalt and 8 wt.% of nickel, solids precipitated at pH 5-10 with 20.15 wt.% of manganese, and the solid product at pH 10-12 with 27.49 wt.% of magnesium. Other separation approaches were also evaluated in this study to assess the possibility of separating cobalt from nickel, including oxidative precipitation and solvent extraction. As a result of all these combined studies, the highest cobalt and nickel purity of 9.92 wt.% and 14 wt. % were generated, respectively, in addition to the manganese (47.9 wt. %) and magnesium (27.49 wt. %) products obtained from the developed process

Peripheral optical errors and their change with accommodation differ between emmetropic and myopic eyes

The progression of myopia is thought to be controlled by the retinal image quality, but its triggering factors are not yet well known. The differences between the peripheral optics in emmetropic and myopic eyes might explain why some eyes become myopic. The present study further investigates peripheral optical quality and how it is affected by accommodation. The refraction and aberrations of the right eyes of five emmetropes and five myopes were measured using a laboratory Hartmann-Shack wave front sensor, specially designed for peripheral measurements with an open field of view. The off-axis optical quality was assessed in steps of 10-out to T40-horizontally and T20-vertically for two different states of accommodation (targets at 0.5 D and 4.0 D). As expected, the emmetropes had a higher relative peripheral myopia, that is, more positive c 2 0 coefficient, than the myopes. The new results of this study are that this well-known difference was found to be asymmetric over the visual field and that it increased with accommodation. This increase was because the relative peripheral defocus profile of the myopes did not show a consistent change between far and near vision, whereas the emmetropes became relatively more myopic in the periphery with accommodation. These findings may indicate a difference between emmetropic and myopic eyes that could be an important clue to understand myopia progression

Tear film stability assessment by corneal reflex image degradation

Postprint (published version

Compensation of presbyopia with the light sword lens

ABSTRACT: We present the first physiological evaluation of the use of the light sword lens (LSL) for presbyopia compensation. The LSL is an axially asymmetric optical element designed for imaging with extended depth of focus. METHODS. A monocular visual simulator setup is implemented to measure visual acuity (VA). Physiological presbyopia is ‘‘mimicked’’ in human subjects by paralysis of the ciliary muscle, using topical application of a muscarinic antagonist. The effect of a contact lens-configured LSL on the mimicked presbyopia visual system is evaluated by measuring VA as a function of target vergence. The ability of the LSL to compensate presbyopia for 2 photopic luminance values was also analyzed. RESULTS. The average VA values for 11 subjects suggest that the LSL can compensate for presbyopia across a wide range of target vergences for which the LSL was designed (-3 to 0D). However, the proposed corrector element causes a loss of distance VA. The mean logMAR VA in that target vergence range was 0.07. The VA curves also show that luminance does not affect the expected behavior of the LSL-corrected presbyopic eye. CONCLUSIONS. These results indicate that the LSL has significant potential as a visual aid for presbyopia

Sensibilidad al desenfoque en sistemas con placas zonales hiperbólicas equilaterales

RESUMEN: Lasplacaszonaleshiperb´olicas equilaterales (PZHE) de foco fijo y de foco variable,las cuales exhiben un patr´on focal en forma de cruz, son elementos que se emplean ensistemas de detecci´on de desplazamientos transversales a grandes distancias, entre otros.No obstante, la forma de la cruz focal que se logra con estos elementos difractivos, se veafectada por el desenfoque producido al hacer registros en planos a distancias distintas aladistanciafocal.Eneldesarrollodeltrabajo,seestudiacomovar´ıa el patr´on focal de las PZHEdefocofijoycomoesafectadalaprecisi´on en la medida del desplazamiento,en planos cercanos al foco de la placa estudiada, con lo que se pretende determinar lasensibilidad al desenfoque de dichos elementos.ABSTRACT: The equilateral hyperbolic zone plates (EHZP) of fixed and variable focal length, whoexhibit cross focal shaped pattern, are elements used in far distance transversal detectionsystems, among others. Nevertheless, the shape that can be achieve with this diffractivesystems, is affected by the out of focus produced when data is taken from planes atdistances different to the focal distance. In this work we study how the focal pattern of afixed focal length EHZP varies and how the precision in the measure of the displacementis affected, in planes close to the focal length of the EHPZ. With this we pretend todetermine the out of focus sensibility of this elements

La sostenibilidad y las cadenas de valor: una mirada desde las condiciones laborales en Colombia

El mantenimiento de las condiciones laborales hasta llegar al trabajo decente pasa por considerar los conceptos de sostenibilidad y de cadenas de valor. Aplicar tales conceptos implica tener en cuenta la responsabilidad de las empresas en el uso de los recursos en las dimensiones sociales, ambientales, económicas y humanas; implica considerar la división de las actividades en primarias y de apoyo, así como su relación con las dimensiones mencionadas anteriormente. La generación del valor compartido, como una extensión de la cadena de valor, hace posible la identificación y el aprovechamiento de nuevas oportunidades de mercado que tienen las empresas para desarrollar su potencial y contribuir al desarrollo económico y social, al disminuir la pobreza. El trabajo decente se convierte en el núcleo alrededor del cual gravitan la sostenibilidad de las empresas, la creación de cadenas de valor compartido, la generación de conocimiento y el mejoramiento de las condiciones laborales

La sostenibilidad y las cadenas de valor: una mirada desde las condiciones laborales en Colombia

Maintaining working conditions to get decent work is to consider the concepts of sustainability and value chains. Apply these concepts involves considering the social and environmental responsibility in the use of natural resources in terms of environmental, economic and social human dimensions; involves considering the division of activities in primary and support related to the dimensions listed above. The generation of shared value, as an extension of the value chain, makes possible the identification and exploitation of new market opportunities for companies to develop their potential and contribute to economic and social development, and poverty reduction. Decent work becomes the core on which gravitates the sustainability of enterprises, creating shared value chains, generating knowledge and improving working conditions.  El mantenimiento de las condiciones laborales hasta llegar al trabajo decente pasa por considerar los conceptos de sostenibilidad y de cadenas de valor. Aplicar tales conceptos implica tener en cuenta la responsabilidad de las empresas en el uso de los recursos en las dimensiones sociales, ambientales, económicas y humanas; implica considerar la división de las actividades en primarias y de apoyo, así como su relación con las dimensiones mencionadas anteriormente. La generación del valor compartido, como una extensión de la cadena de valor, hace posible la identificación y el aprovechamiento de nuevas oportunidades de mercado que tienen las empresas para desarrollar su potencial y contribuir al desarrollo económico y social, al disminuir la pobreza. El trabajo decente se convierte en el núcleo alrededor del cual gravitan la sostenibilidad de las empresas, la creación de cadenas de valor compartido, la generación de conocimiento y el mejoramiento de las condiciones laborales

Chaos in ocular aberration dynamics of the human eye

Since the characterization of the eye’s monochromatic aberration fluctuations in 2001, the power spectrum has remained the most widely used method for analyzing their dynamics. However, the power spectrum does not capture the complexities of the fluctuations. We measured the monochromatic aberration dynamics of six subjects using a Shack-Hartmann sensor sampling at 21 Hz. We characterized the dynamics using techniques from chaos theory. We found that the attractor embedding dimension for all aberrations, for all subjects, was equal to three. The embedding lag averaged across aberrations and subjects was 0.31 ± 0.07 s. The Lyapunov exponent of the rms wavefront error was positive for each subject, with an average value of 0.44 ± 0.15 µm/s. This indicates that the aberration dynamics are chaotic. Implications for future modeling are discussed

Serum “free” iron level changes in children with severe malnutrition after nutritional treatment support. Turbo - Colombia.

ABSTRACT: Iron suplementation is recomended for children with severe mal nutrition (Kwashiorkor), when they have recovered the apetite after nutritional support. However there is evidence suggesting that even when the apetite has been recovered, children still present serum “free” iron traces. Objective: To evaluate serum “free” iron, transferrin, and ferritin levels in children with severe malnutrition (kwashiorkpor) in two different periods of time: at baseline before the nutritional therapy starts, and the moment when children recover the apetite. Methods and materials: Longitudinal, prospective study was setting in Turbo-Antioquia. A total of 40 children aged < 5 Y, who 20 presented marasmus and 20 kwashiorkor. Meassurements like: serum “free” iron by capillary electrophoresis, serum transferrin, total proteins, albumin, iron and C-reactive protein (CRP) were obtained at baseline, and the time when children recover the apetite. Longitudinal analysis was used to evaluate changes in the malnourished group. Results: No significant diferences were found in both groups of malnourish children who had serum free iron before at baseline, and when they recieved nutritional treatment and recovered the appetite. Eventhought significant decrease on Serum free iron level were observed in both groups, there was some remanent trace of the metal in serum. Significant decrease on PCR level was also obtained and serum ferritin level stayed high in the edematous group when they recovering the apetite. Conclusions: Iron supplement is not recomended for children who had recovered the apetite, because they continuing presenting edema and some level of serum “free” iron, low transferrin and high ferritin levels. Iron suplement should be given when edema and infection have disappeared.RESUMEN: se recomida suplemento de hierro en niños con desnutrición aguda grave cuando recuperan el apetito, aun cuando existen evidencias de que en ese momento, aún hay presencia de hierro “libre” y es insuficiente la concentración de transferrina para transportarlo. Objetivo: evaluar el cambio en las concentraciones séricas de hierro libre, transferrina y ferritina en niños con marasmo y kwashiorkor entre el momento uno, al ingreso y el momento dos, después, cuando el niño recuperó el apetito. Materiales y métodos: estudio longitudinal, prospectivo, de tipo antes y después. Se realizó en Turbo, con 40 niños menores de cinco años de los cuales 20 tenían marasmo y 20 kwashiorkor. Se determinaron en ambos momentos: hierro “libre” por electroforesis capilar, transferrina y su índice de saturación, capacidad de fijación de hierro, ferritina, proteínas totales, albúmina, hierro total y proteína C reactiva (PCR) en suero. Resultados: los niños desnutridos presentaron hierro “libre” antes de iniciar el tratamiento nutricional sin diferencias significativas entre marasmáticos y edematosos, para el momento dos la concentración de hierro “libre” disminuyó significativamente en ambos grupos pero aun se encontraban valores del metal. La PCR disminuyó significativamente en ambos grupos y en edematosos la ferritina se mantuvo alta al recuperar el apetito. Conclusiones: la recuperación del apetito no es el momento oportuno para dar suplementos de hierro a los edematosos porque aun tienen hierro “libre”, persiste una baja concentración de transferrina y alta de ferritina; se debe esperar la resolución del edema y de la infección

Role of free iron and oxidative stress in the etiology of oedema in children with Kwashiorkor

ABSTRACT: Kwashiorkor is a serious form of energy-protein malnutrition, different of marasmus in which edema is a major feature. Initial theories explaining this disorder state that low protein intake cause serum albumin deficit, resulting in decreased oncotic pressure, causing water drains into interstitial space. Starting from 1980, several comparative studies had proved that diets of children suffering of either marasmo or Kwashiorkor do not show significant differences in protein content, and a very low protein intake doesn’t result in edematous malnutrition. At the same time researchers found some biochemical alterations in children suffering from kwashiorkor but not in those with marasmus, such as: higher production of oxygen reactivate species, lower antioxidant protection, high ferritine levels, low transferrine levels, and free iron in serum. The above mentioned, allows us to suggest that protein deficiency is not the only decisive factor in the course of severe malnutrition toward kwashiorkor, and that edema could be a consequence for the oxidative damage caused to organic biomolecules by infection and free serum iron.RESUMEN: El Kwashiorkor es una forma grave de malnutrición proteico energética que se diferencia del marasmo, principalmente, por la presencia de edema. Las teorías iniciales que explican esta alteración, sostienen que el bajo consumo de proteína dietaria ocasiona el descenso de la albúmina plasmática y por consiguiente la disminución de la presión oncótica, provocando la salida de agua al espacio intersticial. Estudios comparativos realizados a partir de 1980, no encontraron diferencias significativas en el contenido de proteínas de las dietas ingeridas por niños con marasmo y kwashiorkor y demostraron que el consumo de cantidades mínimas de este nutriente, no siempre desencadena el edema. Al mismo tiempo, varios investigadores hallaron algunas alteraciones bioquímicas en los niños con kwashiorkor pero no en los niños con marasmo, como mayor producción de especies reactivas del oxígeno, menor defensa antioxidante, altas concentraciones de ferritina y disminución de transferrina séricas y hierro “libre” en plasma. Lo anterior sugiere que la deficiencia de proteínas no es el único factor determinante del curso de la desnutrición aguda grave hacia kwashiorkor y que el exceso de agua corporal también puede ser consecuencia del daño oxidativo a biomoléculas orgánicas, ocasionado por la infección y por la presencia de hierro “libre”