Person:
Cuesta Mayorga, Iris

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First Name
Iris
Last Name
Cuesta Mayorga
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Universidad Complutense de Madrid
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Now showing 1 - 4 of 4
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    Remplazamiento de anhidrita por carbonato cálcico: un caso de estudio de procesos de carbonatación mineral
    (2019) Cuesta Mayorga, Iris; Astilleros García-Monge, José Manuel; Fernández Díaz, Lourdes
    The processes of mineral carbonation have played a very important role throughout the history of the Earth. For example, it is considered that large volumes of diagenetic limestones have been formed from carbonation processes of evaporite sulphate deposits, by interaction with carbonated waters. The minerals gypsum (CaSO4·2H2O) and anhydrite (CaSO4) are the main components of this type of deposits. When this doctoral thesis was started, there was vast information about the characteristics of gypsum carbonation, but the knowledge about different aspects of carbonation of anhydrite was more limited. This doctoral thesis has focused on expanding and deepening knowledge of these aspects...
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    Precipitación de polimorfos de CaCO3 en presencia de sulfato
    (Macla, 2018) Cuesta Mayorga, Iris; Astilleros García-Monge, José Manuel; Fernández Díaz, María Lourdes
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    Precipitation of CaCO3 Polymorphs from Aqueous Solutions: The Role of pH and Sulphate Groups
    (Minerals, 2019) Cuesta Mayorga, Iris; Astilleros García-Monge, José Manuel; Fernández Díaz, María Lourdes
    In this work, we aimed to experimentally study the nucleation and growth of CaCO3 phases precipitated from supersaturated aqueous solutions in the presence of varying concentrations of sulphate oxyanion. The experiments were conducted under pH conditions close to neutral (7.6) and by considering a wide range of initial (SO42−)/(CO32−) ratios (0 to approx. 68) in the aqueous solution. We paid special attention to the evolution of the precipitates during ageing within a time framework of 14 days. The mineralogy, morphology, and composition of the precipitates were studied by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and EDX microanalysis. The concentration of sulphate ions in the reacted aqueous solution was studied by ICPs. The experimental results showed that the mineral composition of the precipitate recovered in each run varied with the (SO42−)/(CO32−) ratio in the parental solution, which influenced the mineral evolution of the precipitates during ageing. We observed that high concentrations of sulphate in the aqueous solution stabilized the vaterite precipitates and inhibited calcite formation. Furthermore, aragonite never precipitated directly from the solution, and it was only formed via a dissolution-precipitation process in solutions with a high (SO42−)/(CO32−) ratio after long reaction times. Finally, gypsum only precipitated after long ageing in those aqueous solutions with the highest concentration of sulphate. The reaction pathways during ageing, the morphology of the calcite crystals, and the composition of vaterite and calcite were discussed considering both kinetic and thermodynamic factors. These results showed a considerably more complex behavior of the system than that observed in experiments conducted under higher pHs and supersaturation levels and lower (SO42−)/(CO32−) ratios in the aqueous phase.
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    Epitactic Overgrowths of Calcite (CaCO3) on Anhydrite (CaSO4) Cleavage Surfaces
    (Crystal Growth and Design, 2018) Cuesta Mayorga, Iris; Astilleros García-Monge, José Manuel; Fernández Díaz, María Lourdes; Morales, Juan; Prieto Rubio, Manuel; Roncal-Herrero, Teresa; Benning, Liane G.
    We investigate the crystallographic relationships between calcite crystals overgrown on the (100), (010), and (001) anhydrite cleavage surfaces, as a result of the interaction between anhydrite surfaces with carbonate-rich aqueous solutions. This interaction always leads to oriented nucleation and growth of calcite crystals, characterized by a parallelism between the calcite {1014} faces and the corresponding anhydrite cleavage surface.