Hydrothermal Mineral Deposits

Okrusch, Martin; Frimmel, Hartwig E.

doi:10.1007/978-3-662-57316-7_23

Cited by 3 publications

(9 citation statements)

References 43 publications

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“…These sets of symmetry are identical to the 32 point groups that describe the atomic symmetries . The correlation between the chirality of crystal morphologies and their crystallographic structures has been demonstrated by Pasteur, Donnay and Harker, and the more recent works of Lahav and Leiserowitz. , The geometric symmetry of the external crystal habit is often related to its internal molecular symmetry. − In other words, the point group symmetry of the crystal morphology is dictated by the crystal structure, i.e., the space group of the crystal …”

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confidence: 99%

Crystallographic–Morphological Connections in Star Shaped Metal–Organic Frameworks

et al. 2022

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The symmetry of a crystal's morphology usually reflects the symmetry of the crystallographic packing. For single crystals, the space and point groups allow only a limited number of mathematical descriptions of the morphology (forms), all of which are convex polyhedrons. In contrast, concave polyhedrons are a hallmark of twinning and polycrystallinity and are typically inconsistent with single crystallinity. Here we report a new type of structure: a concave polyhedron shape single crystal having a multidomain appearance and a rare space group (P622). Despite these unusual structural features, the hexagonal symmetry is revealed at the morphological levels.

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confidence: 99%

Crystallographic–Morphological Connections in Star Shaped Metal–Organic Frameworks

et al. 2022

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“…Granite is a felsic plutonic rock with high silicon and aluminum content and medium to coarse grains, and it is among the most common plutonic rocks in the upper continental crust. ,, Granite is a promising candidate for GP synthesis because of its chemical composition and its prevalence worldwide. ,, Mineralogically, granite mainly consists of quartz, plagioclase, K-feldspar, and biotite. , Granite-based GPs can be synthesized through alkali activation or alkali fusion processes. Alkali fusion includes alkali thermal preactivation of less reactive precursors by calcination of a dry mixture of these raw precursors with alkali hydroxides, at temperatures above the alkali hydroxide melting point.…”

Section: Gp Systemsmentioning

confidence: 99%

“…Aplite is a Na-rich, granitic rock with high concentrations of SiO 2 and Al 2 O 3 , which mainly contains alkali-feldspars, quartz, muscovite, oligoclase, and, more rarely, biotite. However, compared to other granites, aplite shows higher reactivity due to its inherently finer crystal size (under 1 mm across). , Norite, a medium-to-coarse-grained mafic plutonic rock consisting mostly of plagioclase and orthopyroxene, is another rock-based precursor that has shown desirable results in laboratory studies . This rock is particularly suited for use as a GP precursor due to its high aluminosilicate (plagioclase) content. , …”

Section: Gp Systemsmentioning

confidence: 99%

Section: Gp Systemsmentioning

confidence: 99%

“… 30 , 103 , 104 Mineralogically, granite mainly consists of quartz, plagioclase, K-feldspar, and biotite. 101 , 102 Granite-based GPs can be synthesized through alkali activation or alkali fusion processes. Alkali fusion includes alkali thermal preactivation of less reactive precursors by calcination of a dry mixture of these raw precursors with alkali hydroxides, at temperatures above the alkali hydroxide melting point.…”

Section: Gp Systemsmentioning

confidence: 99%

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Review on Geopolymers as Wellbore Sealants: State of the Art Optimization for CO₂ Exposure and Perspectives

et al. 2023

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Wellbores used in underground production and storage activities, including carbon capture and storage (CCS), are typically sealed using sealants based on Ordinary Portland Cement (OPC). However, leakage along these seals or through them during CCS operations can pose a significant threat to long-term storage integrity. In this review paper, we explore the potential of geopolymer (GP) systems as alternative sealants in wells exposed to CO 2 during CCS. First, we discuss how key parameters control the mechanical properties, permeability, and chemical durability of GPs based on different starting materials as well as their optimum values. These parameters include the chemical and mineralogical composition, particle size, and particle shape of the precursor materials; the composition of the hardener; the chemistry of the full system (particularly the Si/Al, Si/(Na+K), Si/Ca, Si/Mg, and Si/Fe ratios); the water content of the mix; and the conditions under which curing occurs. Next, we review existing knowledge on the use of GPs as wellbore sealants to identify key knowledge gaps and challenges and the research needed to address these challenges. Our review shows the great potential of GPs as alternative wellbore sealant materials in CCS (as well as other applications) due to their high corrosion durability, low matrix permeability, and good mechanical properties. However, important challenges are identified that require further research, such as mix optimization, taking into account curing and exposure conditions and available starting materials; the development of optimalization workflows, along with building larger data sets on how the identified parameters affect GP properties, can streamline this optimization for future applications.

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New High-Pressure Phases of Titanite-Type CaTiSiO₅ Predicted from First-Principles

Char,

Ghosh,

Ali

et al. 2024

J. Phys. Chem. C

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Titanite-type CaTiSiO 5 is one of the common accessory minerals in igneous, metamorphic, sedimentary, and ultrahigh-pressure rocks. Determination of the high-pressure crystal-chemical behavior of silicates is crucial to comprehending the crystalline materials in deep-earth geospheres. The present study implements a density functional theory calculation assisted structure search method using evolutionary algorithms and reveals two new structural phase transitions: displacive-type monoclinic-II (C2/c) → triclinic (P1) and reconstructive-type triclinic (P1) → orthorhombic (Pnma) at 10 and 18 GPa, respectively. Ab initio molecular dynamics study confirms that the phase transformation sequence remains unaltered at 300 K. Moreover, the orthorhombic structure is quenchable at 0 GPa. The topology of the high-pressure orthorhombic structure can be identified as a combination of corner-shared distorted zigzag SiO 6 octahedra along the [100] direction and an edge-shared TiO 6 prism (with SiO 6 ) along the [001] direction. This novel topological arrangement has not been observed in any of the high-pressure structural prototypes of silicates reported in the literature.

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Hydrothermal Mineral Deposits

Cited by 3 publications

References 43 publications

Crystallographic–Morphological Connections in Star Shaped Metal–Organic Frameworks

Crystallographic–Morphological Connections in Star Shaped Metal–Organic Frameworks

Review on Geopolymers as Wellbore Sealants: State of the Art Optimization for CO₂ Exposure and Perspectives

New High-Pressure Phases of Titanite-Type CaTiSiO₅ Predicted from First-Principles

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Hydrothermal Mineral Deposits

Cited by 3 publications

References 43 publications

Crystallographic–Morphological Connections in Star Shaped Metal–Organic Frameworks

Crystallographic–Morphological Connections in Star Shaped Metal–Organic Frameworks

Review on Geopolymers as Wellbore Sealants: State of the Art Optimization for CO2 Exposure and Perspectives

New High-Pressure Phases of Titanite-Type CaTiSiO5 Predicted from First-Principles

Contact Info

Product

Resources

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Review on Geopolymers as Wellbore Sealants: State of the Art Optimization for CO₂ Exposure and Perspectives

New High-Pressure Phases of Titanite-Type CaTiSiO₅ Predicted from First-Principles