Crystallization via non-classical pathways: Nanoscale imaging of mineral surfaces 

2021 ◽  
Author(s):  
Christine V. Putnis ◽  
Lijun Wang ◽  
Encarnación Ruiz-Agudo ◽  
Cristina Ruiz-Agudo ◽  
François Renard
Keyword(s):  
Crystal Growth ◽  
Imaging Techniques ◽  
Parent Phase ◽  
Aqueous Fluid ◽  
New Mineral ◽  
Fluid Composition ◽  
Mineral Surfaces ◽  
Fluid Interface ◽  
Mineral Growth ◽  
Sem And Tem

<p>The advancement in analytical imaging techniques, including atomic force microscopy (AFM) and scanning and transmission electron microscopies (SEM and TEM), has allowed us to observe processes occurring at mineral surfaces in situ at a nanoscale in real space and time and hence giving the possibility to elucidate reaction mechanisms. Classical crystal growth theories have been established for well over 100 years and while they can still be applied to explain crystal growth in many growth scenarios, we now know that these models are not always an accurate description of the mechanism of all crystal/mineral growth processes, especially where nanoparticle formation is observed. Consequently there is a current challenge at the forefront of understanding crystal/mineral growth mechanisms. This work describes experimental observations of non-classical crystallization processes at the nanoscale. Using AFM as well as SEM and TEM imaging, we demonstrate that many minerals commonly grow by the attachment of nanoparticles on an existing mineral surface, often resulting from the coupling of dissolution of a parent phase and the precipitation of a new product mineral. Through varied examples of crystal/mineral growth, including calcite and other carbonates, barite, brucite, and apatite, we define the importance of the mineral-fluid interface and the aqueous fluid interfacial (boundary) layer in the control of crystal growth. Whether a crystal will grow by classical monomer attachment resulting in step advancement or by the formation, aggregation and merging of nanoparticles, will be controlled by the aqueous fluid composition at the mineral-fluid interface. The processes described also allow for the development of porosity within the new mineral and hence have important consequences for fluid movement and element mobility within the Earth. Additionally an understanding of natural mineral growth has implications for geomimetic applications for the manufacture of functional engineered materials.</p>

Novel Surfactant for Spacer-Less Cementing Compatible with Non Aqueous Fluids

2021 ◽  
Author(s):  
Joseph K. Wee ◽  
Paulo Gomes ◽  
ShanShan Huang ◽  
Emmanuel Therond ◽  
Ansgar Heinrich, Dieker ◽  
...  
Keyword(s):  
Field Trial ◽  
Laboratory Testing ◽  
Scaling Up ◽  
Aqueous Fluid ◽  
Ionic Surfactant ◽  
Fluid Interface ◽  
Cement Slurry ◽  
Synthetic Oil ◽  
Operational Safety ◽  
Wet Surface

Abstract A novel, non-ionic surfactant is presented that alters typical cement incompatibility with non-aqueous fluids, effectively removing synthetic/oil-based mud (SOBM) from the wellbore and changing wettability of casing and formation from oil-wet to water-wet. The change in wettability eliminates the need for cement spacers conventionally deployed between the preceding non-aqueous fluid and the ensuing cement slurry. The entirety of spacer fluid interface can therefore be removed from operation, improving operational safety and efficiency, reduce waste and simplify wellsite logistics. The paper discusses the selection and evaluation of the proprietary surfactant in various laboratory testing. The main characteristics of the surfactant is its non-foaming, non-retarding, compatible with SOBM, ability to change oil-wet surface to water-wet, stable while minimizing environmentally impact. Scaling up, a yard test and a field trial in an offshore rig was successfully performed to evaluate the mixing, compatibility and pumpability using rig equipment.

scholarly journals Kinetic control on the distribution of secondary precipitates during CO2-basalt interactions

2019 ◽  
Vol 98 ◽  
pp. 04006 ◽  
Author(s):  
Helge Hellevang ◽  
Domenik Wolff-Boenisch ◽  
Mohammad Nooraiepour
Keyword(s):  
Spatial Distribution ◽  
Crystal Growth ◽  
Numerical Study ◽  
Numerical Models ◽  
Probabilistic Approach ◽  
Kinetic Control ◽  
Secondary Mineral ◽  
Mineral Growth ◽  
Secondary Precipitates ◽  
Overall Kinetics

A combined experimental and numerical study was undertaken to better understand the spatial distribution of secondary mineral growth along a basalt column. The work demonstrated that few and large crystals formed at random locations. This can only be explained in terms of an overall control by mineral nucleation. The main implication is that a new probabilistic approach must be developed in order to get the overall kinetics and the distribution of crystal growth in the numerical models right.

scholarly journals Editorial for Special Issue “Mineral Surface Reactions at the Nanoscale”

Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 185
Author(s):  
Christine Putnis
Keyword(s):  
Surface Reactions ◽  
Experimental Studies ◽  
Analytical Techniques ◽  
Aqueous Fluid ◽  
Mineral Surfaces ◽  
Special Issue ◽  
Mineral Surface ◽  
Electron Microscopies ◽  
Interface Control ◽  
The Earth

Reactions at mineral surfaces are central to all geochemical processes. As minerals comprise the rocks of the Earth, the processes occurring at the mineral–aqueous fluid interface control the evolution of the rocks and, hence, the structure of the crust of the Earth during such processes at metamorphism, metasomatism, and weathering. In recent years, focus has been concentrated on mineral surface reactions made possible through the development of advanced analytical techniques, such as atomic force microscopy (AFM), advanced electron microscopies (SEM and TEM), phase shift interferometry, confocal Raman spectroscopy, advanced synchrotron-based applications, complemented by molecular simulations, to confirm or predict the results of experimental studies. In particular, the development of analytical methods that allow direct observations of mineral–fluid reactions at the nanoscale have revealed new and significant aspects of the kinetics and mechanisms of reactions taking place in fundamental mineral–fluid systems. These experimental and computational studies have enabled new and exciting possibilities to elucidate the mechanisms that govern mineral–fluid reactions, as well as the kinetics of these processes, and, hence, to enhance our ability to predict potential mineral behavior. In this Special Issue “Mineral Surface Reactions at the Nanoscale”, we present 12 contributions that highlight the role and importance of mineral surfaces in varying fields of research.

scholarly journals Biotite surface chemistry as a function of aqueous fluid composition

2014 ◽  
Vol 128 ◽  
pp. 58-70 ◽  
Author(s):  
Andrew W. Bray ◽  
Liane G. Benning ◽  
Steeve Bonneville ◽  
Eric H. Oelkers
Keyword(s):  
Surface Chemistry ◽  
Aqueous Fluid ◽  
Fluid Composition

Bilayer Rayleigh—Marangoni convection: transitions in flow structures at the interface

1995 ◽  
Vol 451 (1942) ◽  
pp. 487-502 ◽  
Keyword(s):  
Crystal Growth ◽  
Marangoni Convection ◽  
Fluid Flows ◽  
Flow Structures ◽  
Fluid Interface ◽  
Lower Phase ◽  
Fluid Physics ◽  
Physically Based ◽  
Flow Mechanisms ◽  
Total Fluid

The fluid physics of buoyancy-driven (Rayleigh) and interfacial tension-driven (Marangoni) convection is examined for two superimposed layers of fluids. This convection occurs on account of temperature gradients that are imposed perpendicular to the fluid-fluid interface. Interfacial deflections, small as they may be, play an important part in identifying the mechanism that governs the flow, and calculations have been made that indicate whether hot or cold fluid flows towards or away from a crest or a trough. As a result, four possible flow structures or ‘modes’ at the interface have been identified. Two heating styles, heating from below and above, are compared and the behaviour of the fluid physics as a function of total fluid depths, depth ratios and gravity levels is explained. Changes in modes result because of changes in these parameters. We have given plausible physically based arguments that predict the sequential change in modes as these parameters are changed and have ‘verified’ our conjectures with calculations. Flow mechanisms in the case of a solidifying lower phase have also been studied, as this has an application to liquid-encapsulated crystal growth. Where convection is deemed detrimental to crystal homogeneity, we conclude that the liquid-encapsulated method of crystal growth is best conducted under Earth’s gravity.

scholarly journals Prediction of crystal growth morphology based on structural analysis of the solid–fluid interface

Nature ◽  
1995 ◽  
Vol 374 (6520) ◽  
pp. 342-345 ◽  
Author(s):  
X. Y. Liu ◽  
E. S. Boek ◽  
W. J. Briels ◽  
P. Bennema
Keyword(s):  
Crystal Growth ◽  
Structural Analysis ◽  
Fluid Interface ◽  
Growth Morphology

scholarly journals Subduction sediment-lherzolite interaction at 2.9 GPa: effects of metasomatism and partial melting

2019 ◽  
Vol 27 (5) ◽  
pp. 503-524
Author(s):  
A. L. Perchuk ◽  
A A. Serdyuk ◽  
N. G. Zinovievа
Keyword(s):  
Subduction Zones ◽  
Central Zone ◽  
Aqueous Fluid ◽  
Piston Cylinder ◽  
Mineral Growth ◽  
Hydrous Melt ◽  
Liquid Flows ◽  
Dissolved Components ◽  
Sedimentary Layer ◽  
Upper Boundary

We present the results of analogue experiments carried out in a piston–cylinder apparatus at 750–900°C and 2.9 GPa aimed to simulate metasomatic transformation of the fertile mantle caused by fluids and melts released from the subducting sediment. A synthetic H2O- and CO2-bearing mixture that corresponds to the average subducting sediment (GLOSS, Plank, Langmuir, 1998) and mineral fractions of natural lherzolite (analogue of a mantle wedge) were used as starting materials. Experiments demonstrate that the mineral growth in capsules is controlled by ascending fluid and hydrous melt (from 850°C) flows. Migration of the liquids and dissolved components develops three horizontal zones in the sedimentary layer with different mineral parageneses that slightly changed from run to run. In the general case, however, the contents of omphacite and garnet increase towards the upper boundary of the layer. Magnesite and omphacite (± garnet ± melt ± kyanite ± phengite) are widespread in the central zone of the sedimentary layer, whereas SiO2 polymorph (± kyanite ± phengite ± biotite ± omphacite ± melt) occurs in the lower zone. Clinopyroxene disappears at the base of lherzolite layer and the initial olivine is partially replaced by orthopyroxene (± magnesite) in all experiments. In addition, talc is formed in this zone at 750°C, whereas melt appears at 850°C. In the remaining volume of the lherzolite layer, metasomatic transformations affect only grain boundaries where orthopyroxene (± melt ± carbonate) is developed. The described transformations are mainly related to a pervasive flow of liquids. Mineral growth in the narrow wall sides of the capsules is probably caused by a focused flow: omphacite grows up in the sedimentary layer, and talc or omphacite with the melt grow up in the lherzolite layer. Experiments show that metasomatism of peridotite related to a subducting sediment, unlike the metasomatism related to metabasites, does not lead to the formation of garnet-bearing paragenesis. In addition, uprising liquid flows (fluid, melt) do not remove significant amounts of carbon from the metasedimentary layer to the peridotite layer. It is assumed that either more powerful fluxes of aqueous fluid or migration of carbonate-bearing rocks in subduction melanges are necessary for more efficient transfer of crustal carbon from metasediments to a mantle in subduction zones.

Parameters controlling the incorporation of Cu in calcite

2020 ◽  
Author(s):  
Jean-Michel Brazier ◽  
Katja Götschl ◽  
Martin Dietzel ◽  
Vasileios Mavromatis
Keyword(s):  
Growth Rate ◽  
Natural Waters ◽  
Fluid Composition ◽  
Partitioning Coefficient ◽  
Mineral Growth ◽  
Chemical Signatures ◽  
Fundamental Understanding ◽  
First Results ◽  
Ph Conditions ◽  
Co Precipitation

<p>Carbonate minerals record, through their chemical and isotopic composition, the environmental conditions occurring at the time of their formation. Thus, the incorporation of traces/impurities in CaCO<sub>3</sub> minerals calcite and aragonite, have been widely studied over the last five decades in order to provide the fundamental knowledge needed for the use of these traces in paleoenvironmental reconstructions. The processes controlling the uptake of traces in natural samples, however, are manifold and hard to distinguish from each other. Thus, experimental co-precipitation studies on synthetic material under strictly controlled abiotic conditions can provide fundamental understanding on the effect of each process involved in the chemical signatures of natural carbonates. In this study, we explore the incorporation of Cu in calcite and its potential as proxy of reactive fluid composition. This transition metal commonly occurs complexed with organic ligands in natural waters, however, it exhibits very high affinity for calcite. Our experiments were performed at pH 6.3 and 8.3, with varying growth rate ranging between 10<sup>-8.5</sup> and 10<sup>-7.6</sup> (mol/m<sup>2</sup>/s). Our first results highlight that the partitioning coefficient of Cu is positively correlated to the calcite growth rate at both pH conditions, indicating an increase of Cu entrapment at higher growth rate. These new preliminary findings could bring fundamental understanding of Cu incorporation in calcite and highlight the potential of Cu partitioning coefficient as a proxy of mineral growth rate.</p>

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