Le développement de l'idée des droits de l'homme: les tensions contradictoires et les compromis concevables

The main conflicts and antagonisms presently plaguing the world are the conflicting interpretations as to the substance of what constitutes human rights. According to the author, the conflict must be recognized instead of hidden under a list of additional rights which serve only to add heterogeneous requirements. This process is essential and a prerequisite to the search for a rational compromise

Reseña del libro “Después de la crisis”, de Alain Touraine

Este importante libro tiene como objetivo comprender la crisis que vivimos y sus posibles desenlaces. Fue publicado por primera vez en París por Editións Du Seuil en 2010 y acaba de salir en México de los hornos del Fondo de Cultura Económica. En su presentación, Touraine comienza diciendo: “una crisis económica es en primer lugar un asunto de los economistas, aunque no siempre o frecuentemente la hayan previsto”. Pero como podemos constatar, Touraine, desde la perspectiva del soció- logo que es y siempre ha sido, nunca ha rehuido a pensar los grandes cambios que han marcado nuestra atribulada época

Selective recovery of boron, cobalt, gallium and germanium from seawater solar saltworks brines using N-methylglucamine sorbents: column operation performance

The European Union (EU) identified a list of Critical Raw Materials (CRMs) crucial for its economy, aiming to find alternative sources. Seawater is a promising option as it contains almost all elements, although most at low concentrations. However, to the present, the CRMs' recovery from seawater is technically and economically unfeasible. Other alternatives to implement sea mining might be preferred, such as reverse osmosis brines or saltworks bitterns (after sodium chloride crystallisation). The CRMs' extraction in a selective way can be achieved using highly selective recovery processes, such as chelating sorbents. This study focuses on extracting Trace Elements (TEs) from solar saltworks brines, including boron, cobalt, gallium and germanium, using commercial N-methylglucamine sorbents (S108, CRB03, CRB05). The application of these sorbents has shown potential for boron recovery, but their selectivity for cobalt, gallium, and germanium requires further investigation. This research aims to assess these sorbents' kinetics and column mode performance for TEs recovery from synthetic bitterns. Boron and germanium were rapidly sorbed, reaching equilibrium (>90 %) within 1 h, except for S108, which took 2 h. In column mode, 20–25 pore volumes of bittern were treated to remove boron and germanium, but competition from other elements reduced treatment capacity. An acidic elution (1 M hydrochloric acid) allowed to elute them (>90 %), reaching concentration factors for germanium and boron of 35 and 11, respectively, while cobalt and gallium had less affinity for the sorbents. In addition, the experiments performed were fitted by a mass transfer model to determine the equilibrium constants and selectivities. Therefore, bittern mining has been proven as a secondary/alternative source to obtain CRMs, which can lead the EU to a position in which its dependence on other countries to obtain these raw materials would be decreased.This work was supported by the EU within SEArcularMINE (Circular Processing of Seawater Brines from Saltworks for Recovery of Valuable Raw Materials) project – Horizon 2020 programme, Grant Agreement No. 869467. This output reflects only the author's view. The European Health and Digital Executive Agency (HaDEA) and the European Commission cannot be held responsible for any use that may be made of the information contained therein. J. López research was developed under the Margarita Salas postdoctoral fellowship from Ministerio de Universidades (MIU) and funded by the European Union-NextGeneration EU. Support for the research of J.L. Cortina was also received through the “ICREA Academia” recognition for excellence in research funded by the Generalitat de Catalunya.Peer ReviewedPostprint (published version

Recovery of antimony and bismuth from arsenic-containing waste streams from the copper electrorefining circuit: An example of promoting critical metals circularity from secondary resources

The copper pyrometallurgical industry faces the precipitation of un-soluble slimes containing bismuth, arsenic and antimony that can reduce copper purity. Ion-exchange resins are used to treat the electrolyte to avoid their precipitation. After resin saturation, a regeneration stage with 17%(w/w) hydrochloric acid containing antimony and bismuth (e.g. up to 10 g/L) is currently limed. In this work, a selective precipitation process was developed to recover both elements as pure as possible from the eluate, considering that also high contents of As(V) are present. Results showed that during the precipitation process, As(V) forms insoluble antimony-arsenates. Therefore, the eluate was pre-treated to reduce As(V) and Sb(V) using SO2(g) or NaHSO3(s). In this case, it was possible to obtain sequentially antimony oxychloride (Sb4O5Cl2, purity> 93%) and bismuth oxychloride (BiOCl, purity> 95%) under appropriate pH control using sodium hydroxide, sodium bicarbonate and/or sodium carbonate. The use of calcium hydroxide and calcium carbonate resulted in the precipitation of calcium sulphates (CaSO4:H2O(s) and CaSO4:2H2O(s)), which reduced the by-products purity.Peer ReviewedPostprint (author's final draft

Sustainable recovery of critical elements from seawater saltworks bitterns by integration of high selective sorbents and reactive precipitation and crystallisation: Developing the probe of concept with on-site produced chemicals and energy

The availability of raw mineral resources containing elements included in the Critical Raw Materials (CRMs) list is a growing concern for the European Union. Sea mining has been identified as a promising secondary source. In particular, brines obtained in solar saltworks (bitterns) contain relevant amounts of valuable CRMs such as Mg(II), B(III), other alkaline/alkaline earth metals (Rb(I), Cs(I), Sr(II)) and transition/post-transition elements (Co(II), Ga(III), Ge(IV)). However, the low concentration of some of these elements (µg/L) requires an effort to develop recovery routes that are sustainable and economically feasible where the required chemicals and energy are produced on-site from the saltworks bitterns (i.e. HCl and NaOH). Even the conventional recovery processes such as ion exchange, sorption and precipitation, which have proved to be competitive for metals recovery, are challenged in the case of Trace Elements (TEs). This work studies the recovery of TEs included in the CRMs list from saltworks bitterns after ion exchange processes. First, batch crystallisation and reactive precipitation were tested for some target elements in single-component solutions: Sr(II), Co(II), Ga(III), Ge(IV) and B(III). Then, the experiments were carried out with multi-component synthetic solutions assuming different scenarios of bittern streams coming out a selective extraction stage using sorption and ion exchange processes. The targeted elements were recovered except for Ge(IV), where alternative routes need to be evaluated, as its precipitation involves the use of tannic acid or sulphide solutions that could not be produced from the bitterns. However, a further concentration step would be necessary to achieve element concentrations closer to the mineral phases saturation. Moreover, model simulations were performed using the PHREEQC program, which provided a good prediction of the experimental trends obtained in most cases.Peer ReviewedPostprint (published version

Increasing the circularity of the copper metallurgical industry: Recovery of Sb(III) and Bi(III) from hydrochloric solutions by integration of solvating organophosphorous extractants and selective precipitation

The lack of high-purity ores has made the copper industry exploit low-impurity ores containing As, Sb and Bi which can affect the final product quality due to the floating insoluble arsenates. This is usually solved by treating the electrorefining electrolyte in a polishing stage devoted to removing Sb and Bi using aminophosphonic resins. Once the resin is saturated, it is regenerated using 6 M HCl, and the eluate produced is treated with CaO(s) to precipitate both Sb and Bi. However, this stream is of interest due to the inclusion of both elements in the Critical Raw Material list from the European Union. Therefore, the linear management option must be substituted by a circular approach. This work aims to develop such approach by the selective separation and recovery of Sb and Bi from HCl stream polluted with As. The method presented was based on the use of using a solvating mixture of alkylphosphine oxides commercialized as Cyanex 923 dissolved in kerosene and 1-decanol (10 %) as phase modifier. The separation factors of Sb(III) and Bi(III) from As(V) were evaluated and optimized as function of both extractant concentration and the aqueous to organic phase ratio. Results showed that at the lowest Cyanex 923 concentration (0.15 mol/L) and working at an A/O ratio of 1/3, it could be possible to extract 39 % Bi and 78 % Sb with As co-extraction below 2.5 %. Both Sb and Bi were easily recovered (>90 %) using 8 M HNO3 as stripping agent. Following a treatment using NaOH/NaCl or NaOH, both elements could be recovered either as oxychlorides (SbOCl(s) and BiOCl(s)) or oxides (Sb2O3(s) and BisO3(s)).Peer ReviewedPostprint (published version

Evaluation of the purity of magnesium hydroxide recovered from saltwork bitterns

Magnesium has been listed among the 30 critical raw materials by the European Union. In recent years, many green and sustainable alternative Mg2+ sources have been sought to satisfy the EU’s demand and to avoid mineral ore consumption. In this context, saltwork bitterns, the by-products of solar sea salt production, have attracted much attention thanks to their high Mg2+ concentrations (up to 80 g/L) and low Ca2+ and bicarbonate contents (95% (w/w). This work presents a comprehensive experimental effort of reactive precipitation tests with NaOH solutions at stoichiometric and over-stoichiometric concentrations to: (i) assess the technical feasibility of Mg2+ recovery from real bitterns collected in saltworks of the Trapani district (Italy) and, (ii) for the first time, conduct an extensive purity investigation of the precipitated magnesium hydroxide powders as brucite. This experimental investigation demonstrates the possibility of extracting highly valuable compounds from saltwork bittern waste, embracing the water valorization and resource recovery approach.Peer ReviewedPostprint (published version

Unlocking hidden mineral resources: Characterization and potential of bitterns as alternative sources of critical raw materials

Mineral extraction from seawater brines has emerged as a viable solution to reduce Europe's reliance on imported Critical Raw Materials (CRM). However, the economic viability of this approach hinges on the local demand for sodium chloride, the primary product of such extraction processes. This study investigates the potential of residual brines, commonly known as "bitterns," generated during solar sea-salt extraction in traditional saltworks, as an alternative source of minerals. The Mediterranean region, encompassing South-European, North-African, Near East coasts, and parts of the Atlantic regions, is particularly conducive to exploring this prospect due to its extensive solar sea salt industry. Saltworks in the region, adopting various operational strategies based on feed quality or local climate conditions, produce different types of bitterns, each holding a latent resource potential that has remained largely unexplored. Within the framework of the EU-funded SEArcularMINE project, it was conducted an extensive analytical campaign to characterize bitterns collected from a diverse saltworks network. The analysis revealed the presence of sodium, potassium, magnesium, chloride, sulfate, and bromide in concentrations ranging from g/kg, while boron, calcium, lithium, rubidium, and strontium were found in the mg/kg range. Additionally, trace elements (TEs) such as cobalt, cesium, gallium, and germanium were detected at concentrations in the order of µg/kg. Detailed results on the composition of bitterns are presented, emphasizing the distinct characteristics observed at different sites. The estimated potential for mineral recovery from these bitterns is approximately 190 €/m3, considering the production capacity of about 9 Mm3 per year in the Mediterranean area. This finding underscores the significant contribution that mineral recovery from bitterns could make in securing access to CRMs for the European Union.Peer ReviewedPostprint (published version

Interferometric characterization of GRIN lenses for ophtalmic uses

The proposal of this work is the study of a method for characterization of the focal of ophthalmic lenses whosesurface refraction index has been modified by diffusion techniques based on thermal ion exchange in glass. Inparticular the aim is the measurement of the variations in focal length of ophtalmic lenses after undergoing adiffusion process. An interferometric technique has been used and computer simulations have also been carrzedou

Ray tracing for ophthalmic optics. Specific developments for GRIN materials

In this work we present the developments for the simulation of image formation through an ophthalmic lens. The procedure is, essentially an exact ray tracing taking into account the particular mobility conditions of the exit pupil. This leads to the computation of astigmatism as a function of the field angle considered. In the computer program, the use of a commercial glass with a gradient in the refractive index (GRIN material) is foreseen. This latter feature proves to be useful for two practical objectives: modifying the power and the astigmatism of the lens. To illustrate these points, an example based on a lens made by deforming a plane parallel plate of GRIN material will be presented