摘要:
Method for converting metallic silicate minerals to silicon compounds and metal compounds via a conversion reaction, characterized in that the conversion reaction is performed in a gravity pressure vessel (GPV), wherein: the GPV comprises two channels having separate entries on the upper side of the GPV and which channels are mutually connected on the bottom of the GPV, and wherein a dispersion of solid particles of the silicate minerals in water is carried into the GPV in a descending flow, one or more reactants for the conversion reaction are added to the dispersion, and the silicon compounds and metal compounds formed during the conversion reaction are carried away via an ascending flow of the GPV. The method provides a method for sequestration of carbon dioxide, wherein the heat produced can be utilized to form a concentrated gas flow of carbon dioxide prior to sequestration.
摘要:
The present invention provides new compositions containing colloidal nanocrystals with high photoluminescence quantum yields, new synthetic methods for the preparation of highly luminescent colloidal nanocrystals, as well as methods to control the photoluminescent properties of colloidal nanocrystals. For example, this invention encompasses as-prepared nanocrystals that luminesce between about 550 nm and about 675 nm and exhibit a photoluminescence quantum yield (PL QY) greater than or equal to about 40 %. In some embodiments, PL QY between about 50 % and about 80 % are obtainable for nanocrystals that luminesce between about 600 nm and about 650 nm. The new synthetic methods disclosed herein allow photoemission brightness (quantum yield) to be correlated with certain adjustable nanocrystal growth parameters associated with a given synthetic scheme. The PL QY of as-prepared CdSe (and other) semiconductor nanocrystals increases monotonically with time in the early stages of the crystallization process, and then gradually decreases after attaining a maximum point. The time at which a maximum PL QY is attained is referred to as the PL bright point. The position of this bright point, the PL QY value at the bright point, the FWHM of the PL spectra, and several other parameters of the growth process of the CdSe nanocrystals are all strongly dependent on the initial Cd:Se ratio of the precursors in the solution, and certain other experimental parameters. This bright point is different from the point of minimum polydispersity of the nanocrystal sample, referred to as the focusing point of size distribution. CdSe nanocrystals synthesized by this alternative method represent a series of excellent emitters in the orange-red color window in terms of their PL QY, the FWHM of the PL spectra, and the stability of the emission.
摘要:
Sulphides and selenides are prepared by dissolving sulphur or selenium in an aqueous or non-aqueous solution of hydrazine hydrate. The solution is combined with a solution of an appropriate cation to precipitate the corresponding sulphide or selenide. Solutions of two or more cations may be used to produce ternary compounds of sulphur and selenium, for example thio-gallates. Likewise both sulphur and selenium can be used together to produce sulpho-selenides. The method is particularly applicable to the production of doped phosphors by the inclusion of solutions containing the appropriate dopant.
摘要:
Layered oxide products of high thermal stability and surface area which contain interlayer polymeric oxides such as polymeric silica are prepared by ion exchanging a layered metal oxide, such as layered titanium oxide, with organic cation, to spread the layers apart. A compound such as tetraethylorthosilicate, capable of forming a polymeric oxide, is thereafter introduced between the layers. The resulting product is treated to form polymeric oxide, e.g. by hydrolysis, to produce the layered oxide product. The resulting product may be employed as a catalyst material in the conversion of hydrocarbons.
摘要:
Inorganic photoluminescent nanoparticles comprising a solid assembly comprising a first plurality of atoms from group II crystallized with a second plurality of atoms from group VI; at least one dimension of the assembly less than about 3.0 nm; and one or more organocarboxylate agents coupled to a surface that bounds the assembly, wherein the nanocrystal exhibits nanocrystal photoluminescence quantum yield of at least about 10%. Coupling to such surface comprises coating at least a portion of the nanocrystal being coated with the organocarboxylate agent, wherein the organocarboxylate agent is a carboxylic acid or the conjugate base of a carboxylic acid. The carboxylic acid can be is selected from formic acid, acetic acid, hexanoic acid, octanoic acid, oleic acid, and benzoic acid. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present invention.
摘要:
There are provided: compound semiconductor particles that can display more excellent performance in functions peculiar to the compound semiconductor (e.g. luminosity and luminescence efficiency); and a production process for obtaining such compound semiconductor particles with economy, good productivity, and ease. Compound semiconductor particles, according to the present invention, are characterized by comprising body particles and a metal oxide, wherein the body particles have particle diameters of smaller than 1 µm and are covered with the metal oxide and include a compound semiconductor including an essential element combination of at least one element X selected from the group consisting of C, Si, Ge, Sn, Pb, N, P, As, Sb, S, Se, and Te and at least one metal element M that is not identical with the element X, and wherein the metal oxide is a metal oxide to which an acyloxyl group is bonded.
摘要:
Die Erfindung betrifft ein Verfahren zur Aufarbeitung von Rückständen der Bariumsulfid- oder Strontiumsulfid-Laugerei. Dazu setzt man die Rückstände mit Salzsäure und Schwefelsäure um unter Bildung einer Säurelösung und trennt die Feststoffe ab. Vorzugsweise schliesst man die abgetrennten Feststoffe mit einer wässrigen Alkalilösung auf unter Bildung einer alkalischen Extraktlösung und einem Extraktionsrückstand und trennt die Rückstände ab. Die zu deponierenden Rückstände werden auf diese Weise wesentlich verringert.
摘要:
Die Erfindung betrifft ein Verfahren zur Abtrennung von Schwermetallen aus Abwässern sowie Fällungsmittel zur Durchführung dieses Verfahrens und Verfahren zur Herstellung des Fällungsmittels. Es ist bekannt, zur Abtrennung von Schwermetallen aus Abwässern die alkalische, hydroxidische Fällung sowie die sulfidische Fällung zu verwenden. Diesen bekannten Verfahren haften jedoch gravierende Nachteile an, welche letztlich deren Einsatz in der Praxis verhindert haben. Nach der Lehre der erfinderischen Aufgabe wird vorgeschlagen, bei einem gattungsgemäßen Verfahren die an sich vorhandenen Vorteile der sulfidischen Fällung im sauren Medium, nämlich die außerordentlich niedrigen Restlöslichkeiten der Schwermetalle, unter erheblicher Herabsetzung der Gefahren einer evtl. Überdosierung miteinander zu vereinigen, d.h. Sicherheit gegen die Bildung von Schwefelwasserstoff. Das verwendete Fällungsmittel ist derart ausgebildet, daß im behandelten Abwasser die sulfidischen und sonstigen Niederschläge bei einem pH-Wert von ca. 7,5 selbsttätig ausflocken, wobei ein Abtrennen des Schlammes vom klaren Wasser ohne Zusatz von Flockungsmitteln erfolgt. Das Mittel zur Abtrennung von Schwermetallen besteht vorteilhaft aus Erdalkalipolysulfiden oder Gemischen aus Erdalkalipolysulfiden mit anderen Erdalkali-Schwefel-Verbindungen.
摘要:
An adherent, transparent moisture barrier is applied to alkaline earth sulfide phosphor particles by stirring in an anhydrous polar solvent including a fluorinating compound present in a concentration of no higher than 0.02 molar until a transparent fluorine-containing moisture-impervious coating has been applied to the particles. The polar solvent is removed and the coated particles dried. A second moisture barrier can also be applied to ensure long term resistance of the phosphors to degradation by moisture.