Person:
Astilleros García-Monge, José Manuel

First Name

José Manuel

Last Name

Astilleros García-Monge

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Geológicas

Department

Mineralogía y Petrología

Area

Cristalografía y Mineralogía

Identifiers

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Now showing 1 - 10 of 85

Malachite Crystallisation in a Diffusing-Reacting System
(Wiley-VCH Verlag, 1998) Astilleros García-Monge, José Manuel; Pina Martínez, Carlos Manuel; Fernández Díaz, Lurdes; López Andrés, Sol
The crystallisation of malachite has been studied in a system involving the counter diffusion of Cu2+ and CO3 through a silica gel column at 25 ºC. In such a system supersaturation is a function of time and position along gel column. Under these conditions kinetic variables are required in order to justify nucleation behaviour. Supersaturation rate has revealed as the most important parameter controlling nucleation features (waiting time, position of the precipitate, and metastability levels). The results presented here confirm the general nucleation behaviour reported by Prieto et al., (1989, 1991, 1994) for other carbonates. On the other hand, supersaturation changes during crystallisation process control the morphological evolution of malachite crystals.
Metastable phenomena on calcite {1014} surfaces growing from Sr2+–Ca2+–CO3 2- aqueous solutions
(Elsevier Science B.V., Amsterdam., 2003) Astilleros García-Monge, José Manuel; Pina Martínez, Carlos Manuel; Fernández Díaz, Lurdes; Putnis, Andrew
In situ atomic force microscopy (AFM) experiments, scanning electron microscopy (SEM) imaging and composition analysis, and X-ray diffraction have provided information about the growth, dissolution and transformation processes promoted by Sr2 + –Ca2 + –CO3 2 aqueous solutions in contact with calcite {101¯4} surfaces. Experiments have shown a wide variety of surface phenomena, such as the influence of the Sr-bearing newly-formed surface on the subsequent growth (template effect), the growth and subsequent dissolution of surfaces and the nucleation of secondary three-dimensional nuclei on calcite surfaces. These phenomena reveal the metastability of the crystallisation system and are a consequence of the interplay between thermodynamics (the relative stability of the two calcite and aragonite structure solid solutions that can be formed), supersaturation of the aqueous solution with respect to the two possible solid solutions, and the crystallographic control of the surfaces on cation incorporation.
Reaction pathways and textural aspects of the replacement of anhydrite by calcite at 25 °Ck
(Mineralogical Society of America, 2017) Roncal-Herrero, Teresa; Astilleros García-Monge, José Manuel; Bots, Pieter; Rodríguez-Blanco, Juan Diego; Prieto, Manuel; Benning, Liane G.; Fernández Díaz, Lurdes
The replacement of sulfate minerals by calcium carbonate polymorphs (carbonation) has important implications in various geological processes occurring in Earth surface environments. In this paper we report the results of an experimental study of the interaction between anhydrite (100), (010), and (001) surfaces and Na2CO3 aqueous solutions under ambient conditions. Carbonation progress was monitored by glancing incidence X‑ray diffraction (GIXRD) and scanning electron microscopy (SEM).We show that the reaction progresses through the dissolution of anhydrite and the simultaneous growth of calcite. The growth of calcite occurs oriented on the three anhydrite cleavage surfaces and its formation is accompanied by minor vaterite. The progress of the carbonation always occurs from the outer-ward to the inner-ward surfaces and its rate depends on the anhydrite surface considered, with the (001) surface being much more reactive than the (010) and (100) surfaces. The thickness of the formed carbonate layer grows linearly with time. The original external shape of the anhydrite crystals and their surface details (e.g., cleavage steps) are preserved during the carbonation reaction. Textural characteristics of the transformed regions, such as the gradation in the size of calcite crystals, from ~2 mm in the outer region to ~17 mm at the calcite-anhydrite interface, the local preservation of calcite crystalographic orientation with respect to anhydrite and the distribution of the microporosity mainly within the carbonate layer without development of any significant gap at the calcite- nhydrite interface. Finally, we compare these results on anhydrite arbonation with those on gypsum carbonation and can explain the differences on the basis of four parameters: (1) the molar volume change involved in the replacement process in each case, (2) the lack/existence of epitactic growth between parent and product phases, (3) the kinetics of dissolution of the different surfaces, and (4) the chemical composition (amount of structural water) of the parent phases.
Nanoscale processes during the interaction of aluminosilicate and carbonate mineral surfaces with acid mine drainage (AMD)
(Elsevier Science Ltd, 2009) Kollias, K.; Godelitsas, Athanasios; Astilleros García-Monge, José Manuel; Ladas, S.; Kennou, S.; Potamitis, C.; Zervou, M.; Lagoyiannis, A.; Harissopulos, S.; Mavromoustakos, Th.
Estudio del Efecto del Ca en el Crecimiento y Hábito de la Barita
(Sociedad Española de Mineralogía, 2011-09) Ibáñez de Aldecoa, Juan; Astilleros García-Monge, José Manuel; Sánchez Pastor, Nuria; Fernández Díaz, Lurdes
Supersaturation functions in binary solid solution–aqueous solution systems
(Elsevier Science Ltd, 2003) Astilleros García-Monge, José Manuel; Pina Martínez, Carlos Manuel; Fernández Díaz, Lurdes; Putnis, Andrew
In this paper, we present a brief review of the thermodynamic equilibrium of binary solid solution–aqueous solution (SS-AS) systems and derive an expression hat allows us to evaluate the supersaturation or undersaturation of a given aqueous solution with respect to the whole range of solid compositions: the δ(x) function. Such an expression is based on the two conditions that define the SS-AS thermodynamic equilibrium. The derivation of the new supersaturation function, δ(x), was made by considering in detail the compositional relationships between solid and aqueous phases. To represent the new formulation on Lippmann diagrams, we have defined a new thermodynamic concept: the “actual activity.” In addition, we show how our supersaturation function behaves for both ideal and subregular solid solutions. The behaviour and applicability of both the δ(x) function and a previous supersaturation function, β(x), defined by Prieto et al. (1993), is discussed.
Uptake of dissolved lead by anhydrite surfaces
(Elsevier, 2014) Morales, Juan; Astilleros García-Monge, José Manuel; Jiménez, Amalia; Göttlicher, Jorg; Steininger, Ralph; Fernández Díaz, Lurdes
The fate of harmful metals in the Earth crust is importantly affected by sorption processes on mineral surfaces. Here, a study of the ability of anhydrite surfaces to uptake dissolved Pb is presented. Experiments were conducted at room temperature using initial Pb concentration ([Pbaq]0) ranging between 10 and 1000 mg/L and a batch type set-up. Inductively coupled plasma optical emission spectrometry analyses showed that [Pbaq] progressively decreased as the time of interaction increased, to reach a final steady state value of ~3.0 mg/L, irrespectively of [Pbaq]0. However, the time elapsed before the steady state value was reached strongly depended on [Pbaq]0, with the drop to this final value occurring in less than 1 day interaction when [Pbaq]0 ≥ 50 mg/L and after 20 days when [Pbaq]0 < 50 mg/L. Scanning Electron Microscopy and X-ray diffraction analyses confirmed the epitactic growth of anglesite (PbSO4) crystals on anhydrite surfaces when [Pbaq]0 ≥ 50 mg/L. X-ray Absorption Near Edge Structure spectroscopy points to a different sorption mechanisms when [Pbaq]0 < 50 mg/L. The results show that the epitactic growth of anglesite on anhydrite has no significant impact on the ability of anhydrite surfaces to remove Pbaq, which show equal effectiveness as that of gypsum surfaces. The high reactivity of anhydrite surfaces renders this phase potentially important in the control of the fate of dissolved metals in nature.
Interaction of gypsum with lead in aqueous solutions
(Elsevier, 2010) Astilleros García-Monge, José Manuel; Godelitsas, Athanasios; Rodríguez Blanco, Juan Diego; Fernández Díaz, Lurdes; Prieto Rubio, Manuel; Lagoyannis, Anastasios; Harissopulos, Sotirios V.
Sorption processes on mineral surfaces are a critical factor in controlling the distribution and accumulation of potentially harmful metals in the environment. This work investigates the effectiveness of gypsum (CaSO42H2O) to sequester Pb. The interaction of gypsum fragments with Pb-bearing solutions (10, 100 and 1000 mg/L) was monitored by performing macroscopic batch-type experiments conducted at room temperature. The aqueous phase composition was periodically determined by Atomic Absorption Spectrometry (AAS), Ion Chromatography (IC) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP–OES). Regardless of the [Pbaq]initial, a [Pbaq]final < 4 mg/L was always reached. The uptake process was fast (t < 1 h) for [Pbaq]initialP100 mg/L and significantly slower (t > 1 week) for [Pbaq]initial = 10 mg/L. Speciation calculations revealed that after a long time of interaction (1 month), all the solutions reached equilibrium with respect to both gypsum and anglesite. For [Pbaq]initialP100 mg/L, sorption takes place mainly via the rapid dissolution of gypsum and the simultaneous formation of anglesite both on the gypsum surface and in the bulk solution. In the case of [Pbaq]initial = 10 mg/L, no anglesite precipitation was observed, but surface spectroscopy (proton Rutherford Backscattering Spectroscopy, p-RBS) confirmed the formation of Pb-bearing surface layers on the (0 1 0) gypsum surface in this case also. This study shows that the surface of gypsum can play an important role in the attenuation of Pb in contaminated waters.
Nuevos datos sobre el origen de las mineralizaciones de celestina (SrSO4) de la cuenca de Granada
(Sociedad Española de Mineralogía, 2018-07) Forjanes, Pablo; Astilleros García-Monge, José Manuel; Fernández Díaz, Lurdes; Nieto, José Miguel
La cristalización de (Ca,Sr)CO3 sobre superficies{1014} de calcita
(Seminario de Estudos Galegos. Area de Xeoloxía e Minería ; Instituto Universitario de Xeoloxía "Isidro Parga Pondal", 2000) Astilleros García-Monge, José Manuel; Pina Martínez, Carlos Manuel; Fernández Díaz, Lurdes; Putnis, Andrew