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Showing papers on "Sodium silicate published in 1996"


Journal ArticleDOI
TL;DR: In this paper, the reaction below 100 °C of a dehydroxylated clay (metakaolinite: (Al2O3)(SiO2)2(H2O)005) suspended in an alkaline sodium silicate solution (Na2O),SiO 2)14(H 2O)x) leads to an amorphous glassy aluminosilicate, called in this work "low-temperature inorganic polymer glass" (LTIPG or IPG)
Abstract: The reaction below 100 °C of a dehydroxylated clay (metakaolinite: (Al2O3)(SiO2)2(H2O)005) suspended in an alkaline sodium silicate solution ((Na2O)(SiO2)14(H2O)x) leads to an amorphous glassy aluminosilicate, called in this work “low-temperature inorganic polymer glass” (LTIPG or IPG)

259 citations


Journal ArticleDOI
15 Oct 1996
TL;DR: In this article, the synthesis of colloidal polypyrrole-magnetite-silica nanocomposites is described, where pyrrole is chemically polymerized using (NH4)2S2O8, H2O2/Fe3+/HCl, or FeCl3oxidants in the presence of these silica-coated magnetite particles.
Abstract: The synthesis of colloidal polypyrrole–magnetite-silica nanocomposites is described. First, silica-coated magnetite particles were prepared by the aqueous deposition of silica onto ultrafine (5–20 nm) magnetite particles via controlled hydrolysis of sodium silicate. Then pyrrole was chemically polymerized using (NH4)2S2O8, H2O2/Fe3+/HCl, or FeCl3oxidants in the presence of these silica-coated magnetite particles to yield colloidal dispersions of polypyrrole–magnetite–silica particles. The magnetite contents of these materials were as high as 17.5% by mass. Vibrating sample magnetometry measurements confirmed that these nanocomposites were superparamagnetic, with bulk saturation magnetization values of up to 10.9 emu g−1. Disc centrifuge photosedimentometry was used to assess particle size and degree of dispersion, yielding weight-average particle diameters in the range 100–520 nm. Electron microscopy studies indicated a rather ill-defined particle morphology but provided some evidence for the magnetite component within the nanocomposites. Stable colloidal dispersions were obtained using the H2O2/Fe3+/HCl and (NH4)2S2O8, oxidants, whereas FeCl3-based syntheses yielded only flocculated particles or macroscopic precipitates under similar conditions. Solid-state electrical conductivities of nanocomposites synthesized using (NH4)2S2O8, H2O2/Fe3+/HCl, and FeCl3were about 10−3, 10−2, and 10−1S cm−1, respectively.

91 citations


Journal ArticleDOI
25 Dec 1996-Langmuir
TL;DR: In this paper, the effect of ionic aluminate and silicate species on the structure of surfactant aggregates used in the preparation of mesoporous aluminosilicates was investigated using dynamic light scattering and rheological techniques.
Abstract: The effect of ionic aluminate and silicate species on the structure of surfactant aggregates used in the preparation of mesoporous aluminosilicates was investigated using dynamic light scattering and rheological techniques Aqueous cetyltrimethylammonium chloride (CTAC) solutions saturated with sodium aluminate, sodium silicate, or tetramethylammonium silicate were studied over a wide range of CTAC concentrations (10−250 wt %), which included both spherical and rod-shaped micellar regimes Sodium aluminate was observed to have no effect on the structure of CTAC micelles and so plays no role in aggregate formation in the prereaction stage of the production of aluminosilicates such as MCM-41 Silicate anions from sodium silicate and tetramethylammonium silicate strongly affected CTAC micelle formation, promoting the formation of flexible wormlike micelles at dilute concentrations in which elongated wormlike micelles are not entangled The condensation of silicate ion with the tetramethylammonium cation in

78 citations


Journal ArticleDOI
TL;DR: In this paper, the optical properties of chromium-doped sodium silicate glass synthesized under oxidizing conditions have been investigated and the Dq, B-and C-parameters of the crystal-field theory for the ion were obtained, confirming the glassy nature of the sample.
Abstract: The optical properties of chromium-doped sodium silicate glass synthesized under oxidizing conditions have been investigated. The method of preparation provides a large concentration of ions, but absorption and emission spectra showed that a small amount of (and ) ions are always present. The Dq-, B- and C-parameters of the crystal-field theory for the ion were obtained, confirming the glassy nature of the sample. luminescence was observed in the near-infrared region, even at room temperature, confirming the low value of the crystal-field Dq. Moreover, the high ultraviolet transparency of this matrix allows observation of a well resolved absorption spectrum of the ion.

51 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of sodium silicate addition on phase formation in high alumina cement (HAC) during hydration was studied, and a reaction mechanism involving stratlingite formation in the HAC-sodium silicate system was postulated.

44 citations


Journal ArticleDOI
TL;DR: In this article, the chemical structure of sodium aluminosilicate glasses is determined by high-resolution x-ray photoelectron spectroscopy (XPS) as silicon is gradually replaced by aluminum.
Abstract: The chemical structure of sodium aluminosilicate glasses is determined by high resolution x‐ray photoelectron spectroscopy (XPS) as silicon is gradually replaced by aluminum. A well‐defined chemical state is found for silicon, aluminum, and sodium atoms, while three different environments are identified for oxygen atoms corresponding to Si–O–Si, Si–O–Al, and Si–O–Na bonds. The binding energy of Na 1s photoelectrons increases significantly with increasing aluminum substitution while that of Al 2p and components of O 1s photoelectrons remains approximately constant. Thus, the ionicity of sodium increases with aluminum amount, but the over all electron density around silicon, aluminum, and different types of oxygen atoms remains unchanged. The dielectric constant of the glasses increases with increasing aluminum substitution. It is analyzed in terms of the polarizabilities of constituent structural units, viz., silicon tetrahedra, nonbridging oxygen–sodium ion pairs, and aluminum tetrahedron–sodium ion pairs...

36 citations


Patent
03 Jun 1996
TL;DR: In this article, a method for treating a metal surface involves contacting the metal surface with an aqueous silicate solution, contacting the silicate-coated metal surfaces with an aminopropyl silane and water.
Abstract: A method for treating a metal surface involves contacting the metal surface with an aqueous silicate solution, contacting the silicate-coated metal surface with an aqueous organo-functional silane solution, and then contacting the silane-coated metal surface with a chrome-free pretreatment. Preferably, the bath containing the aqueous silicate solution also includes a cleaning agent for cleaning the metal surface. Alternatively, the metal surface may be cleaned in a separate step before the metal surface is contacted with the aqueous silicate solution and, optionally, the metal surface is rinsed with water after the metal surface is cleaned and before the metal surface is contacted with the aqueous silicate solution. The silicate-coated metal surface may be rinsed with water before it is contacted with an aqueous organo-functional silane solution. In addition, the silane-coated metal surface may be rinsed with water before it is contacted with a chrome-free pretreatment. As an alternative or in addition to these rinsing steps, excess solution may be removed from the silicate-coated or silane-coated metal surface prior to the subsequent steps. Preferably, the aqueous silicate solution includes water and either sodium silicate or potassium silicate, and the aqueous organo-functional silane solution comprises an aminopropyl silane and water.

33 citations


Patent
15 Oct 1996
TL;DR: In this article, the authors propose a FCC catalyst consisting of a crystalline aluminosilicate zeolite, gibbsite, rare earth metal compound and a silica matrix prepared from at least one of the two types of solutes made by an ion exchange process and an acidic silica sol prepared by mixing sodium silicate, an acid and an aluminum salt of an acid.
Abstract: A FCC catalyst having improved coke selectivity and a FCC process for converting hydrocarbon feedstocks to lower boiling products. The catalyst comprises a crystalline aluminosilicate zeolite, gibbsite, rare earth metal compound and a silica matrix prepared from at least one of a silica sol made by an ion-exchange process and an acidic silica sol prepared by mixing sodium silicate, an acid and an aluminum salt of an acid.

30 citations


Patent
14 Feb 1996
TL;DR: In this article, a crystalline sheet sodium silicate of the general formula xNa2O ySiO2 zP2O5 was described, in which the ratio of x to y corresponds to a number from 0.35 to 0.6, and y to z corresponds to the ratio from 1.75 to 1200.
Abstract: The invention relates to a crystalline sheet sodium silicate of the general formula xNa2O ySiO2 zP2O5 in which the ratio of x to y corresponds to a number from 0.35 to 0.6, the ratio of x to z corresponds to a number from 1.75 to 1200 and the ratio of y to z corresponds to a number from 4 to 2800, a process for its preparation and its use.

28 citations


Journal ArticleDOI
TL;DR: In this paper, a consistent model for the variation of the porous structure of aluminosilicates with the Al content is proposed, based mainly on the degree of incorporation of Al in the tetrahedral network and subsequent changes in the condensation reactivity.

27 citations


Patent
05 Nov 1996
TL;DR: An improved form of calcium carbonate which is acid resistant to enable its use as a filler material in the making of neutral to weakly acidic paper, and a process for producing this acid-resistant calcite is provided in this article.
Abstract: An improved form of calcium carbonate which is acid resistant to enable its use as a filler material in the making of neutral to weakly acidic paper, and a process for producing this acid-resistant calcium carbonate is provided. This acid-resistant calcium carbonate composition comprises calcium carbonate and at least about 0.1% to about 25% based on the dry weight of the calcium carbonate, of sodium silicate, together with at least 0.1% to about 25 percent, based on the dry weight of the calcium carbonate, of a weak acid, such as phosphoric acid, formic acid, fluoroboric acid, polyacrylic acid, or alum, or a mixture of weak acids, such as phosphoric acid and polyacrylic acid.

Patent
12 Feb 1996
TL;DR: In this paper, an in situ process for making improved zeolitic fluid cracking catalyst by spray drying a mixture of hydrous kaolin, gibbsite and spinel, essentially free from metakaolin, calcining the resulting microspheres to convert the hydrous kimol to metakaol whereby the gibbsite is hydrothermally converted to a transitional alumina.
Abstract: An in situ process for making improved zeolitic fluid cracking catalyst by spray drying a mixture of hydrous kaolin, gibbsite and spinel, essentially free from metakaolin, calcining the resulting microspheres to convert the hydrous kaolin to metakaolin whereby the gibbsite is hydrothermally converted to a transitional alumina, and reacting the microspheres composed of a mixture of spinel, transitional alumina and metakaolin with a seeded alkaline sodium silicate solution

Patent
11 Jun 1996
TL;DR: In this paper, the authors proposed a flame-retardant polymeric and inorganic compound composition for electrical insulation materials, automotive electrical equipment, aerospace materials, etc., which is suitable for electrical insulating materials.
Abstract: PROBLEM TO BE SOLVED: To obtain the subject composition comprising each specific silicon- based polymer and inorganic compound, having sufficiently high flame retardancy owing to the synergistic effect of these two components, and suitable for electrical insulation materials, automotive electrical equipment, aerospace materials, etc. SOLUTION: This flame-retardant composition comprises (A) 100 pts.wt. of a silicon-based polymer of formula I or formula II (R -R are each an alkyl or aryl; Y is O or a divalent aliphatic or aromatic hydrocarbon; (m) is 1-10; (n) is >=1) and (B) 0.1-300 (pref. 1-200) pts.wt. of an inorganic compound selected from respective silicates or borates of groups Ia, IIa and IIIa elements, silicon oxide, aluminum oxide and boron oxide. The polymer of formula I is e.g. poly(dimethylsiloxane), while the polymer of formula II e.g. poly(dimethylsilylene). The silicate or borate of groups Ia-IIIa element is e.g. sodium silicate, calcium borate.

Patent
21 Nov 1996
TL;DR: In this article, a method of preparing a substrate for a planographic printing plate comprises contacting a support, for example of aluminium or plastics, with a liquid having a pH of 9 or greater and comprising a silicate solution, in which particulate material, such as alumina or titania, are dispersed.
Abstract: A method of preparing a substrate for a planographic printing plate comprises contacting a support, for example of aluminium or plastics, with a liquid having a pH of 9 or greater and comprising a silicate solution, for example sodium silicate solution, in which particulate material, for example of alumina or titania, are dispersed. The liquid when cured produces a hydrophilic layer on the support. A substrate per se and a printing plate are also described.

Journal ArticleDOI
TL;DR: In this article, the microporous structure of the active top layer remains stable up to 873 K and is characterised by a mean pore diameter of 1.6 nm, a narrow pore size distribution and a porosity of 35%.

Patent
05 Nov 1996
TL;DR: In this paper, a process for preparing organically modified aerogels, in which a silicic acid sol having a pH of ≤ 4.0 is prepared from an aqueous sodium silicate solution using at least one organic and/or inorganic acid, is described.
Abstract: The invention concerns a process for preparing organically modified aerogels, in which: a) a silicic acid sol having a pH of ≤ 4.0 is prepared from an aqueous sodium silicate solution using at least one organic and/or inorganic acid; b) the resultant silicic acid sol is polycondensed to form an SiO2 gel by the addition of a base; c) the gel obtained in step b) is washed with an organic solvent until the water content of the gel is ≤ 5 wt.%; d) the gel obtained in step c) is surface-silylated; and e) the surface-silylated gel obtained in step d) is dried. The process is characterized in that the at least one acid forms salts with the sodium silicate cations in the silicic acid sol, which salts are difficult to dissolve. Before step b) the salts produced which are difficult to dissolve are precipitated out to the greatest extent possible and separated from the silicic acid sol.

Patent
31 Dec 1996
TL;DR: In this article, a powder of silica-cerium oxide composite particles is proposed to be used as an ultraviolet shielding agent or as a sunscreening agent in a cosmetic composition.
Abstract: Proposed is a powder of silica-cerium oxide composite particles useful as an ultraviolet shielding agent in a resin composition or as a sunscreening agent in a cosmetic composition. The cerium oxide-based composite particles consist of cerium oxide and 5 to 60% by weight of amorphous silica calculated as SiO2. The composite particles are prepared by the addition of sodium silicate and an inorganic acid to an aqueous slurry containing precipitates of cerium hydroxide so as to precipitate amorphous silica on the particles of cerium hydroxide followed by drying and calcination of the particles separated from the reaction mixture. Various formulations of cosmetic compositions compounded with the silica-cerium oxide composite particles are disclosed.

Patent
15 Oct 1996
TL;DR: In this article, the authors propose a crystalline aluminosilicate zeolite, gibbsite, and a silica matrix for converting hydrocarbon feedstocks to lower boiling products.
Abstract: A FCC catalyst having improved coke selectivity and greater catalyst strength, and a FCC process for converting hydrocarbon feedstocks to lower boiling products. The catalyst comprises a crystalline aluminosilicate zeolite, gibbsite, and a silica matrix prepared from at least one of a silica sol made by an ion-exchange process and an acidic silica sol prepared by mixing sodium silicate, an acid and an aluminum salt of an acid.

Journal ArticleDOI
TL;DR: In this paper, a poly(acrylic acid) complex was copolymerized in benzene in the presence of layered sodium silicate (δ-Na 2 Si 2 O 5 ) powder.
Abstract: Acrylic acid and crosslinking agent [poly(ethylene glycol)-diacrylate or divinylbenzene] were copolymerized in benzene in the presence of layered sodium silicate (δ-Na 2 Si 2 O 5 ) powder. The resultant poly(acrylic acid) complex shows large water absorbability, for which dependency on crosslinking degree was investigated.

Journal ArticleDOI
TL;DR: In this article, the structure change during a process from a layered sodium silicate, kanemite, to a noble mesoporous silica, folding sheet mesophorous materials (FSM), was studied by 29 Si-MAS-NMR and X-ray powder diffraction.
Abstract: Structure change during a process from a layered sodium silicate, kanemite, to a noble mesoporous silica, folding sheet mesoporous materials (FSM), was studied by 29 Si-MAS-NMR and X-ray powder diffraction. Cation exchange of Na + in the kanemite for hexadecyltrimethylammonium (HDTMA) ion folded unit silica sheets to form an HDTMA/silica intermediate with nano-scale hexagonal symmetry. Following pH adjustment at 8.5 promoted condensation reactions between adjacent silica sheets to form an HDTMA/silica complex, which caused local rearrangement of SiO 4 -tetrahedra in the sheets. Removing the organic component from the HDTMA/silica complex by calcination at 550 °C gave a porous silica where uniform nano-scale pores were arranged regularly. XRD patterns suggested a characteristic SiO 4 -tetrahedra arrangement in the walls of the porous materials.

Journal ArticleDOI
TL;DR: Stray field magnetic resonance imaging (STRAFI) is shown to be highly suited to the study of drying processes in thin films and suggests that the localized hydrogen spin-spin relaxation time, and hence the mobility of the water in the films is independent of the drying regime and depends primarily on the local water concentration.

Patent
12 Jun 1996
TL;DR: In this paper, a rare earth-based permanent magnet such as a neodymium-iron-boron permanent magnet can be imparted with high corrosion resistance by providing the surface with a protective coating film of vitrified alkali metal silicate, e.g., sodium silicate.
Abstract: A rare earth-based permanent magnet such as a neodymium-iron-boron permanent magnet, which is disadvantageous in respect of the low corrosion resistance, can be imparted with high corrosion resistance by providing the surface with a protective coating film of vitrified alkali metal silicate, e.g., sodium silicate, of which the SiO 2 :(alkali metal oxide) molar ratio is in the range from 1.5 to 20. The vitrified alkali metal silicate-based protective coating film can be formed by coating the surface of the magnet with an aqueous coating solution containing sodium silicate to form a coating layer which is dried and subjected to a heat treatment at 50° to 450° C. to effect vitrification of the alkali metal silicate. The thickness of the thus formed protective coating film should be in the range from 5 nm to 10 μm. The protective effect of the vitrified sodium silicate-based coating film can be further improved by admixing the coating solution with finely divided silica particles of 5 to 50 nm average particle diameter.

Journal ArticleDOI
11 May 1996
TL;DR: In this article, an optimization of the extraction procedure and determination of the factors that influence impurities are the factors which influence the reactivity of silica was studied and optimized, and pure amorphous silica with RHA:NaOH ratio of 1.5 and sodium silicate concentration (measured in specific gravity) was obtained.
Abstract: Although the chemical extraction of silica from rice husk ash (RHA) is well established; its reactivity in the synthesis of zeolites have not been studied and optimized. Due to the complex nature of silica, the extraction procedure is important in ensuring production of highly reactive silica. This paper reports on the optimization of the extraction procedure and determination of the factors that influence impurities are the factors that influence the reactivity of silica. Pure amorphous silica was obtained with RHA:NaOH ratio of 1.5 and sodium silicate concentration (measured in specific gravity) of 1.2-1.5. Reactivity rests of the extracted silica via crystallization of zeolite Y in reaction mixtures of various basicity show that pure zeolite Y was formed from the sample containing 85% Si0 2 with neutral or slightly basic property. In contrast,crystallization in the presence of silica source that is acidic containing a low percentage of Si0 2 favours the formation of zeolite P.

Journal ArticleDOI
TL;DR: In this paper, the optimal conditions of the precipitation process of high dispersion degrees from the solution of sodium metasilicate were given, and a physicochemical analysis and microscopic structure of the obtained silicates were performed.
Abstract: Presents the outcome of intensive research into highly dispersed sodium‐aluminium silicate. Optimal conditions of the precipitation process of sodium‐aluminium silicates of high dispersion degrees from the solution of sodium metasilicate were given. In the precipitation process water soluble aluminium salts were used. A physicochemical analysis and microscopic structure of the obtained silicates were performed. The products obtained are characterized by parameters comparable to those of the sodium‐aluminium silicate P‐820 (Degussa).

Journal ArticleDOI
TL;DR: The structural changes of glass microballoon with thermal treatment up to 973 K were examined in this paper, showing that the ultramicropores accessible only to H2O molecules in SB gradually decreased by heating and disappeared by heating at 773 K.
Abstract: Glass microballoons (GB) of about 1 mm in diameter were prepared by ultrasonic spray pyrolysis from sodium silicate solution. A silica-rich type of glass microballoons (SB) was prepared by acid treatment of GB. The structural changes of both microballoons with thermal treatment up to 973 K were examined. Both GB and SB showed properties similar to hydrated sodium silicate glass, to some extent. SB was more thermally stable than GB, but the spherical structures of both microballoons were collapsed by heating at 973 K; cristobalite was observed in samples heated at 973 K. The loosely and tightly incorporated water molecules evolved up to 573 K and near 850 K, respectively. The crystallization of cristobalite caused tightly incorporated water molecules to develop. The ultramicropores accessible only to H2O molecules in SB gradually decreased by heating and disappeared by heating at 773 K.

Journal ArticleDOI
TL;DR: An electrochemical study of antimony ions doped in soduim borate and silicate glass melts was investigated by differential pulse voltammetry at various temperatures, by which Sb 5+ Sb 3+ redox reactions were observed as discussed by the authors.
Abstract: An electrochemical study of antimony ions doped in soduim borate and silicate glass melts was investigated by differential pulse voltammetry at various temperatures, by which Sb 5+ Sb 3+ redox reactions were observed. The half wave potentials for reduction of Sb 5+ to Sb 3+ shifted toward negative values with increasing Na 2 O content of the glass-forming liquids and with decreasing temperature. Substitution of Na 2 O by CaO in sodium silicate liquids shifted the half wave potential to the positive side. These results correspond to an increase of the content of pentavalent antimony ions with an increase of the basicity of the glass-forming liquids.

Patent
06 Mar 1996
TL;DR: The process for the treatment of wood in the form of particles intended to be incorporated as a filler in concrete consists in drying the wood until a residual moisture content of the order of 10 to 15%, corresponding to the content due to natural drying and in balance with wood under shelter.
Abstract: of EP0517577The process for the treatment of wood in the form of particles intended to be incorporated as a filler in concrete consists in drying the wood until a residual moisture content of the order of 10 to 15%, corresponding to the content due to natural drying and in balance with wood under shelter, is achieved, in coating the particles thus dried with pyrogenic silica and in fixing this pyrogenic silica on the wood by spraying a sodium silicate solution.

Patent
06 Nov 1996
TL;DR: In this paper, the high alkalinity sodium silicale solution and silicic acid are mixed, neutralized and precipitated to obtain silica gel and white carbon black.
Abstract: Zirkite is alkaline decomposed and high alkalinity sodium silicate solution is separated by immersion the decomposed product in water. The precipitate is acidified to obtain silicic acid (silica gel). The high alkalinity sodium silicale solution and silicic acid are mixed, neutralized and precipitated. After filtration and washing, drying, grinding, white carbon black is obtd.. The process is simple, capital cost is low, raw material consumption and production cost are also low.

Journal Article
TL;DR: In this article, the performance of various chemical additives on the stabilization of well bore walls is reviewed, including dilute silicate muds and Potassium silicate was used in combating problems with differentially stuck pipe.
Abstract: Although drilling fluids with soluble-silicate additives are not used as often as in the past, experiments in China indicate these additives can help stabilize problem clays in some well bores, and therefore warrant further attention. The earlier silicate muds contained more than 30% sodium silicate. Their rheological properties were hard to control, and their high alkalinity was a hazard. In recent years, silicate muds have been used again, at lower concentrations, in China and in Russia to consolidate well walls. A number of deep wells have been drilled with dilute silicate muds in the south Xinjiang area. Potassium silicate was helpful in combating problems with differentially stuck pipe. This paper reviews the performance of the various chemical additives on the stabilization of well bore walls.

Patent
29 Nov 1996
TL;DR: A silicate-containing aqueous solution composition comprising: a) from 10 % to 50 % of a silicate compound selected from sodium and potassium silicates, or a mixture of such silicate compounds; b) from 1 % w/w to 5 % w /w of a salt, the cations of which are selected from either sodium and/or potassium ions, and the anions of which were selected from halogen, sulfate and carbonate ions; c) from 0.25% to 5% of ethylene glycol; and d) water
Abstract: A silicate-containing aqueous solution composition comprising: a) from 10 % w/w to 50 % w/w of a silicate compound selected from sodium and potassium silicates, or a mixture of such silicate compounds; b) from 1 % w/w to 5 % w/w of a salt, the cations of which are selected from sodium and potassium ions, and the anions of which are selected from halogen, sulfate and carbonate ions, or a mixture of such salts; c) from 0.25 % w/w to 5 % w/w of ethylene glycol; and d) water. The silicate compound is preferably sodium silicate, especially sodium silicate having an average formula of Na2SiO3, Na6Si2O7, Na2Si3O7, or Na2Si4O9, or mixtures thereof. The salt is preferably sodium chloride. The composition is useful in encapsulating pollutants, fireproofing flammable materials and extinguishing fires.