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BookDOI

Handbook of hydrothermal technology

TL;DR: The Handbook of Hydrothermal Technology as discussed by the authors provides a single source for understanding how aqueous solvents or mineralizers work under temperature and pressure to dissolve and recrystallize normally insoluble materials, and decompose or recycle any waste material.
Abstract: Quartz, zeolites, gemstones, perovskite type oxides, ferrite, carbon allotropes, complex coordinated compounds and many more -- all products now being produced using hydrothermal technology. Handbook of Hydrothermal Technology brings together the latest techniques in this rapidly advancing field in one exceptionally useful, long-needed volume. The handbook provides a single source for understanding how aqueous solvents or mineralizers work under temperature and pressure to dissolve and recrystallize normally insoluble materials, and decompose or recycle any waste material. The result, as the authors show in the book, is technologically the most efficient method in crystal growth, materials processing, and waste treatment. The book gives scientists and technologists an overview of the entire subject including: Evolution of the technology from geology to widespread industrial use. Descriptions of equipment used in the process and how it works. Problems involved with the growth of crystals, processing of technological materials, environmental and safety issues. Analysis of the direction of today's technology. In addition, readers get a close look at the hydrothermal synthesis of zeolites, fluorides, sulfides, tungstates, and molybdates, as well as native elements and simple oxides. Delving into the commercial production of various types, the authors clarify the effects of temperature, pressure, solvents, and various other chemical components on the hydrothermal processes. * Gives an overview of the evolution of Hydrothermal Technology from geology to widespread industrial use* Describes the equipment used in the process and how it works* Discusses problems involved with the growth of crystals, processing of technological materials, and environmental and safety issues
Citations
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Journal ArticleDOI
TL;DR: The flexibility and reliability of this synthetic approach is demonstrated here for the transformation of transition-metal oxides into high-quality anisotropic nanomaterials.
Abstract: The discovery of carbon nanotubes in 1991 is a milestone in nanomaterials research. Since then, more and more anisotropic nanoparticles have been detected and characterized. The development of nanodevices might benefit from the distinct morphology and high aspect ratio of nanorods and nanotubes as these can be functionalized in unique ways such as incorporation of nanorods in nanotubes. Downscaling a broad range of materials to 1D nanoscopic structures is currently the focus of a rapidly growing scientific community. Developing general pathways to this goal would transfer a wide variety of properties to the nanoscale-a spectrum of phenomena so diverse that it would cover not only inorganic systems but all of materials science. Synthesis of real functional materials, however, always involves considerable synthetic ingenuity, interdisciplinary collaboration, as well as technological and economical realism. The major topic of this review is to provide a survey of recent progress in the synthesis of oxidic nanotubes and nanorods-with their non-oxidic counterparts briefly highlighted-and to outline the major synthetic routes leading to them. With the challenges of synthesizing bulk oxidic materials in mind, the establishment of trustworthy and uncomplicated ways of providing them as anisotropic nano-modules on an industrial scale appears to be more or less serendipity. Of the methods utilized in nanotube and nanorod synthesis solvothermal processes have emerged as powerful tools for generalizing and systematizing controlled syntheses of nano-morphologies. The flexibility and reliability of this synthetic approach is demonstrated here for the transformation of transition-metal oxides into high-quality anisotropic nanomaterials.

1,033 citations

Journal ArticleDOI
TL;DR: The importance of hydrothermal technology in the preparation of nanomaterials has been discussed in detail with reference to the processing of advanced materials for nanotechnology as discussed by the authors, and the role of supercritical water and supercritical fluids is discussed with appropriate examples.

830 citations

Journal ArticleDOI
TL;DR: The photocatalytic activity of the as-prepared nanocrystalline mesoporous TiO2 powders was evaluated by the degradation of acetone (CH3COCH3) under UV-light irradiation at room temperature in air as mentioned in this paper.
Abstract: Bimodal nanocrystalline mesoporous TiO2 powders with high photocatalytic activity were prepared by a hydrothermal method using tetrabutylorthotitanate (TiO(C4H9)4, TBOT) as precursor. The as-prepared TiO2 powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and N2 adsorption–desorption measurements. The photocatalytic activity of the as-prepared TiO2 powders was evaluated by the photocatalytic degradation of acetone (CH3COCH3) under UV-light irradiation at room temperature in air. The effects of hydrothermal temperature and time on the microstructures and photocatalytic activity of the TiO2 powders were investigated and discussed. It was found that hydrothermal treatment enhanced the phase transformation of the TiO2 powders from amorphous to anatase and crystallization of anatase. All TiO2 powders after hydrothermal treatment showed bimodal pore-size distributions in the mesoporous region: one was intra-aggregated pores with maximum pore diameters of ca. 4–8 nm and the other with inter-aggregated pores with maximum pore diameters of ca. 45–50 nm. With increasing hydrothermal temperature and time, the average crystallite size and average pore size increased, in contrast, the Brunauer-Emmett-Teller (BET) specific surface areas, pore volumes and porosity steadily decreased. An optimal hydrothermal condition (180 °C for 10 h) was determined. The photocatalytic activity of the prepared TiO2 powders under optimal hydrothermal conditions was more than three times higher than that of Degussa P25.

533 citations

Journal ArticleDOI
TL;DR: An overview of the past, present and future perspective of hydrothermal technology as a tool to fabricate advanced materials has been given with appropriate examples in this article, where some recent developments in multi-energy processing of materials are discussed.
Abstract: The hydrothermal technique provides an excellent possibility for processing of advanced materials whether it is bulk single crystals, or fine particles, or nanoparticles. The advantages of hydrothermal technology have been discussed in comparison with the conventional methods of materials processing. The current trends in hydrothermal materials processing has been described in relation to the concept of soft solution processing, as a single-step low energy consuming fabrication technique. Also some recent developments in multi-energy processing of materials such as microwave-hydrothermal, mechanochemical-hydrothermal, electrochemical-hydrothermal, sonar-hydrothermal, etc. have been discussed. An overview of the past, present and future perspective of hydrothermal technology as a tool to fabricate advanced materials has been given with appropriate examples.

490 citations

References
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Journal ArticleDOI
TL;DR: A review of the past, present, and future of the hydroxyapatite (HAp)-based biomaterials from the point of view of preparation of hard tissue replacement implants is presented in this paper.
Abstract: This paper reviews the past, present, and future of the hydroxyapatite (HAp)-based biomaterials from the point of view of preparation of hard tissue replacement implants. Properties of the hard tissues are also described. The mechanical reliability of the pure HAp ceramics is low, therefore it cannot be used as artificial teeth or bones. For these reasons, various HAp-based composites have been fabricated, but only the HAp-coated titanium alloys have found wide application. Among the others, the microstructurally controlled HAp ceramics such as fibers/whiskers-reinforced HAp, fibrous HAp-reinforced polymers, or biomimetically fabricated HAp/collagen composites seem to be the most suitable ceramic materials for the future hard tissue replacement implants.

1,892 citations

Journal ArticleDOI
TL;DR: In this article, the previously common distinction between hydrothermal conditions below and pneumatolytic conditions above the critical point is no longer made, since no discontinuities are observed upon exceeding the critical conditions.
Abstract: “Hydrothermal synthesis” usually refers to heterogeneous reactions in aqueous media above 100°C and 1 bar. The previously common distinction between hydrothermal conditions below and pneumatolytic conditions above the critical point is no longer made, since no discontinuities are observed upon exceeding the critical conditions. Under hydrothermal conditions, reactants otherwise difficult to dissolve go into solution as complexes, in whose formation water itself or very soluble “mineralizers” can participate. Thus, one can obtain the conditions of chemical transport reactions,[1] of which hydrothermal syntheses can be considered a special case. During recent decades in the geological sciences—in which the method is also historically rooted—it has received a strong impulse, whose effect on preparative solid state chemistry is discussed here.

679 citations

Journal ArticleDOI
TL;DR: In this paper, phase relations in a portion of the granite system, KAlSi3O8-NaAlSi 3O8 NaAlSi8-SiO2-H2O have been studied in the pressure range 4 to 10 kb, where melting begins at 625°C at an isobaric invariant point involving albite + orthoclase + quartz + liquid + vapor.
Abstract: Phase relations in a portion of the granite system, KAlSi3O8-NaAlSi3O8-SiO2-H2O have been studied in the pressure range 4 to 10 kb. At 10 kb, melting begins at 625°C at an isobaric invariant point involving albite + orthoclase + quartz + liquid + vapor. The anhydrous composition of the liquid at this isobaric quaternary eutectic corresponds to 21 orthoclase: 56 albite: 23 quartz in contrast to that at the isobaric quaternary minimum at 0.5 kb, where the liquid corresponds to 31 orthoclase: 30 albite: 39 quartz. This represents a shift of the liquid, in anhydrous projection, almost directly toward NaAlSi with increasing P. The quaternary minimum in this system becomes a eutectic at approximately 3.6 kb. Compositional comparisons among granites, aplites, zoned pegmatites, and the quaternary minimum and eutectic suggest that igneous pegmatites and aplites represent magmas that were saturated or nearly saturated with water when they began to crystallize. Trends in bulk composition among pegmatites further suggest selective losses of alkalies during crystallization, probably by diffusion through aqueous fluids coexisting with the silicate melts and their solid products.

614 citations

Book
01 Jan 1997
TL;DR: In this paper, the economic classification of metals metal production and recycling of metals by-product and secondary metals is discussed, including the following classes of metals: primary metals: copper lead zinc lead zinc tin nickel primary metals secondary metals: arsenic antimony bismuth Cadmium Mercury Cobalt Light Metals: Beryllium Magnesium Aluminium Titanium Precious metals: Gold Silver Platinum Group Metals Refractory metals: Tungsten Molybdenum Niobium Tantalum Zirconium Hafnium Vanadium R
Abstract: The Metal Industry: The Economic Classification of Metals Metal Production Recycling of Metals By-Product Metals Ferrous Metals: Iron Steel Ferroalloys Primary Metals: Copper Lead Zinc Tin Nickel Secondary Metals: Arsenic Antimony Bismuth Cadmium Mercury Cobalt Light Metals: Beryllium Magnesium Aluminium Titanium Precious Metals: Gold Silver Platinum Group Metals Refractory Metals: Tungsten Molybdenum Niobium Tantalum Zirconium Hafnium Vanadium Rhenium Scattered Metals: Germanium Gallium Indium Thallium Selenium Tellurium Radioactive Metals: Uranium Thorium Plutonium Rare Earths Ferroalloy Metals: Chromium Manganese Silicon Boron Alkali Metals: Lithium Sodium Potassium Rubidium Cesium Alkaline Earth Metals: Calcium Strontium Barium Special Topics: Hydrides Carbides Nitrides Cyano Compounds Peroxo Compounds.

548 citations

Journal ArticleDOI
TL;DR: In this article, the liquidus phase relationship has been determined experimentally for the system Qz-Ab-Or with excess water and 1, 2, and 4 wt.% added fluorine at 1 kb pressure.
Abstract: Liquidus phase relationships have been determined experimentally for the system Qz-Ab-Or with excess water and 1, 2, and 4 wt.% added fluorine at 1 kb pressure. With increasing fluorine content the position of the quartz-alkali feldspar field boundary moves away from the quartz apex. The position of the minimum melting composition and the minimum liquidus temperature change progressively from Qz37Ab34Or29 and 730° C for the fluorine free system (Tuttle and Bowen 1958) to Qz15Ab58Or27 and 630° C for the system with 4 wt.% added fluorine. Exploratory experiments have been carried out below the liquidus, and have indicated that for certain bulk compositions an assemblage consisting of two alkali feldspars, quartz, melt and vapour can exist at temperatures as low as 550° C at 1 kb.

546 citations