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Showing papers on "Sodium silicate published in 1994"


Journal ArticleDOI
01 Dec 1994-Langmuir
TL;DR: In this article, a method for the preparation of charged and sterically stabilized rod-like silica particles is presented, where boehmite needles are synthesized hyhydrothermal treatment of aqueous aluminum alkoxide solutions.
Abstract: A method is presented for the preparation of charged and sterically stabilized rodlike silica particles. First, boehmite needles are synthesized hyhydrothermal treatment of aqueous aluminum alkoxide solutions. Then controlled silica growth on the needles takes place in an aqueous sodium silicate solution without formation of aggregates or homogeneous silica particles. Finally grafting reactions are performed with (fluorescent) silanes and octadecyl alcohol to obtain stable dispersions in organic solvents. Special attention is given to the silica-covered rods grafted with a dense octadecyl brush, which form isotropic (flow birefringent) dispersions and translucent (permanent birefringent) incompressible low-density sediments in cyclohexane

94 citations


Patent
27 Dec 1994
TL;DR: In this paper, the authors defined a modulus (molar ratio of SiO2 to Na2 O) of 1.3 to 4 in the form of a fine-particle solid in shard-like form or compounds containing these silicates with the ability to reduce incrustation when used as a builder component.
Abstract: The invention relates to sodium silicates with a modulus (molar ratio of SiO2 to Na2 O) of 1.3 to 4 in the form of a fine-particle solid in shard-like form or compounds containing these silicates with the ability to reduce incrustation when used as a builder component in detergents. These useful materials are distinguished in particular by the fact that they are in the form of an X-ray amorphous overdried material (primary drying product) with water contents below 15% by weight and apparent densities of the non-compacted solid granules of 500 g/l or lower which has been produced by drying of a water-containing sodium silicate preparation using a hot gas phase as the drying medium and/or by heating of a spray-dried sodium silicate with water contents of at least 15% by weight at temperatures of 120°to 450° C., if necessary accompanied or followed by the application of forces to produce the shard-like structure. The invention also relates to multicomponent mixtures from the field of solid detergents or multicomponent compounds suitable for this field of application which are characterized by the presence of the sodium silicates defined above.

71 citations


Patent
07 Sep 1994
TL;DR: In this paper, the authors provided hollow borosilicate microspheres having a mean particle size between 15 and 20 microns, and a true density below 0.25 g/cc.
Abstract: The present invention provides hollow borosilicate microspheres having a mean particle size between 15 and 20 microns, and a true density below 0.25 g/cc. The invention also provides a method for making such microspheres comprising spray drying a solution of sodium silicate and sodium borate in a spray tower to form a precursor, milling the precursor, and heating the crushed precursor to a temperature in excess of 600° F. to form hollow borosilicate microspheres.

67 citations


Journal ArticleDOI
TL;DR: X-ray photoelectron spectroscopy (XPS) has revealed physical and chemical structure differences between aluminum and boron substituted sodium silicate glasses, Na2O · xR2O3 · (3 − 2x)SiO2, prepared by a melt quench method, where R = Al or B, and x = 0, 02, 04, 06, 08, 1 The structure of sodium aluminosilicate (SAS) glasses deduced from the analysis of XPS data is found to agree with the four-coordinated aluminum structure model
Abstract: X-ray photoelectron spectroscopy (XPS) has revealed physical and chemical structure differences between aluminum and boron substituted sodium silicate glasses, Na2O · xR2O3 · (3 − 2x)SiO2, prepared by a melt quench method, where R = Al or B, and x = 0, 02, 04, 06, 08, 1 The structure of sodium aluminosilicate (SAS) glasses deduced from the analysis of XPS data is found to agree with the four-coordinated aluminum structure model with Na balancing the local charge The structure of sodium borosilicate (SBS) glasses is mostly consistent with Bray's model with the need to consider a ‘contending factor’ for Na Sodium is not fully ionized as often assumed Its ionicity increases in both SAS and SBS glasses with increasing Al/B substitution Net charge on atoms according to Pauling's model has been calculated as a guidance in analyzing the XPS spectra

56 citations


Patent
17 Feb 1994
TL;DR: In this paper, a method of removing a core from a molded product in which the core is formed of a particulate inert material, such as.[.sand-bound.sand, bound.Iaddend.
Abstract: A method of removing a core from a molded product in which the core is formed of a particulate inert material, such as .[.sand-bound.]. .Iadd.sand, bound .Iaddend.together by a cured binder of a water soluble carbohydrate alone or mixed with a silicate is disclosed. The silicate is preferably an alkali earth metal silicate, preferably sodium silicate, and the carbohydrate is preferably a saccharide or starch. The binder is cured by heat. The core and molded product are exposed to water, preferably heated water in a bath or steam, to rapidly disintegrate the core and remove it from the molded product.

40 citations


Journal ArticleDOI
TL;DR: In this article, an electrical conductivity procedure has been used to measure the effective diffusivities of compounds in cementitious systems containing the additives fly ash, silica fume, sodium silicate and bentonite.

33 citations



Journal ArticleDOI
TL;DR: In this paper, a study of alkali activation of slag, using a combination of sodium silicate or water glass (Na2SiO3) and slaked lime, is presented.

29 citations


Patent
25 May 1994
TL;DR: The humidity exchanger medium is manufactured by forming a laminate of (i) a corrugated sheet and (ii) a flat sheet bonded to points of contact of a ridged surface of the sheet, the laminate having been impregnated with sodium silicate waterglass and then partially dried as discussed by the authors.
Abstract: The humidity exchanger medium is manufactured by forming a laminate of (i) a corrugated sheet and (ii) a flat sheet bonded to points of contact of a ridged surface of the corrugated sheet, the laminate having been impregnated with sodium silicate waterglass and then partially dried, each corrugated and flat sheet constituted of a paper of inorganic fibers; forming a honeycomb matrix from at least one laminate; soaking the honeycomb matrix in an acidic solution containing at least a titanium inorganic salt to convert the sodium silicate waterglass to a titanium-containing silicate hydrogel; and washing and drying the honeycomb matrix to convert the titanium-containing silicate hydrogel to a titanium-containing silicate aerogel.

26 citations


Journal ArticleDOI
TL;DR: The morphology of all-silica sodalite is calculated using surface simulation techniques, and is found to compare favourably with the experimentally observed morphology as discussed by the authors, and the morphology is compared with the observed morphology.
Abstract: The morphology of all-silica sodalite is calculated using surface simulation techniques, and is found to compare favourably with the experimentally observed morphology.

25 citations


Patent
28 Sep 1994
TL;DR: In this paper, an in situ process making improved zeolitic fluid cracking catalyst by spray drying a mixture of hydrous kaolin and spinel, essentially free from metakaolin, calcining the resulting microspheres to convert the hydrous kolin to metakaol, and reacting microsheres composed of a mix of spinel and metakaols with a seeded alkaline sodium silicate solution.
Abstract: An in situ process making improved zeolitic fluid cracking catalyst by spray drying a mixture of hydrous kaolin and spinel, essentially free from metakaolin, calcining the resulting microspheres to convert the hydrous kaolin to metakaolin, and reacting microspheres composed of a mixture of spinel and metakaolin forms of calcined clay with a seeded alkaline sodium silicate solution. The weight percent of hydrous kaolin in the starting (uncalcined) microspheres is greater than the spinel content.

Journal ArticleDOI
TL;DR: In this article, the effectiveness of sodium silicate and trisodium phosphate as corrosion inhibitors for iron in 0.1 m NaClO4, in both aerated and deaerated solutions has been investigated.
Abstract: The effectiveness of sodium silicate (Na2SiO3) and trisodium phosphate (Na3PO4) as corrosion inhibitors for iron in 0.1 m NaClO4, in both aerated and deaerated solutions has been investigated. Both sodium silicate and trisodium phosphate are effective inhibitors in unbuffered solutions as a result of inhibiting the rate of the anodic iron dissolution reaction. However, the inhibition of the corrosion rate in the (final) pH range 9.6–11.6 is entirely due to the change in pH which the addition of Na2SiO3 and Na3PO4 to unbuffered solutions causes, and not to the presence of silicate/phosphate species. Where the final pH was in the range 5–7 addition of I mm sodium silicate to acidified aerated unbuffered solutions caused slight inhibition of the iron dissolution reaction when compared with a solution of the same pH. Lower concentrations of Na2SiO3 at the same final pH did not cause inhibition. Silicic acid has an approximate solubility of 1 mm and it is likely that the inhibitive behaviour in this pH range is due to the precipitation of H2SiO3 at the electrode surface. An aerated phosphate buffer of pH 7.0 inhibited both the anodic and cathodic reactions when compared with a 0.1 m sodium perchlorate solution at the same pH. This was due to the presence of phosphate species at the electrode surface. In carbonate and acetate buffers neither Na2SiO3 nor Na3PO4 caused corrosion inhibition.

Journal ArticleDOI
TL;DR: In this article, the incorporation of silver in sodium silicate glasses by a silver-sodium ion exchange was studied and the extended X-ray absorption fine structure results at the silver K-edge show that the silver ions are surrounded by oxygen in the first coordination sphere.
Abstract: The present experiments were performed to study the incorporation of silver in sodium silicate glasses by a silver-sodium ion exchange. The extended X-ray absorption fine structure results at the silver K-edge show that the silver ions are surrounded by oxygen in the first coordination sphere. It could be observed structural rearrangements in dependence on both the silver-sodium exchange ratio and the thermal treatment.

Patent
31 Mar 1994
TL;DR: In this article, a combination of steps which maximizes contaminant removal, minimizes waste volume, and produces a treatable waste solid is proposed. But the results are limited to a single solution and the preferred precipitants are sodium silicate and ammonium hydroxide.
Abstract: Solutions such as for example drinking water, ground water and extracting solutions contaminated with heavy metals and radioactive species, singly or in combination, are treated by first treating the contaminated solution with silicate and ammonium hydroxide solution precipitants. Then the contaminated solution is separately treated with an acid which gels, polymerizes and/or precipitates the contaminant-containing silica matrix to form an easily dewaterable and separable solid. The solid contaminants are readily removed from the cleansed solution by filtration means. The process utilizes a novel combination of steps which maximizes contaminant removal, minimizes waste volume, and produces a treatable waste solid. The preferred precipitants are sodium silicate, and ammonium hydroxide. The preferred mineral acid is hydrochloric acid.

Patent
19 Jul 1994
TL;DR: In this article, a method for producing crystalline synthetic faujasite of the zeolite "X" type is disclosed. But this method requires the use of a mixture of two different solutions: a sodium silicate solution and a sodium aluminate solution.
Abstract: A method for producing crystalline synthetic faujasite of the zeolite "X" type is disclosed. The method comprises (a) separately preparing a sodium silicate solution and a sodium aluminate solution, (b) admixing the sodium silicate solution and the sodium aluminate solution at high shear until a mixture results having a ratio of sodium oxide to silica of 0.4:1 to 2:1, silica to alumina of 2.2:1 to 3.5:1, and water to sodium oxide of 20:1 to 70:1, (c) heating said mixture to a temperature of about 80° to 120° C. in the absence of any further mixing for a period of time sufficient to produce the desired crystalline faujasite of the zeolite "X" type, and (d) recovering said zeolite "X".

Journal ArticleDOI
TL;DR: In this article, the effect of process variables on the dissociation reaction has been studied and it is found that the reaction is strongly influenced by the input power to the plasma torch, rate of flow of plasma gas and carrier gas and location of powder feed port.

Patent
02 Feb 1994
TL;DR: In this article, a process for the manufacture of pure amorphous silica from rocks containing non-crystalline silica is described, which comprises the steps of: (a) dissolution of said rock in an alkaline solution comprising of sodium hydroxide and sodium carbonate, obtaining a solution of sodium silicate; (b) precipitation, by adding sodium bicarbonate into said sodium silicates and co-producing sodium carbonates, the weight ratio between SiO 2 and Na 2 O in said dissolution step is in the range of between 0.5
Abstract: A process for the manufacture of pure amorphous silica from rocks containing non-crystalline silica is described. The process comprises the steps of: (a) dissolution of said rock in an alkaline solution comprising sodium hydroxide and sodium carbonate, obtaining a solution of sodium silicate; (b) precipitation of pure amorphous silica by adding sodium bicarbonate into said sodium silicate and co-producing sodium carbonate, the weight ratio between SiO 2 and Na 2 O in said dissolution step is in the range of between 0.5 to 3.0; and (c) the sodium carbonate solution is transformed into crystalline sodium bicarbonate, by a salting out reaction with sodium chloride, being recycled to the process. According to a preferred embodiment, the alkaline solution is obtained by the caustification of sodium carbonate with calcium hydroxide. The preferred concentration of sodium hydroxide in said dissolution step is in the range of 4% to 14% by weight.

Journal ArticleDOI
TL;DR: In this paper, the authors confirm a hydrogel-solid transformation mechanism for silicalite crystallization from tetrapropylammonium (TPA + ) sodium silicate gels was studied by X-ray diffraction, elemental analysis, ion exchange, and scanning electron microscopy.

Patent
29 Sep 1994
TL;DR: In this paper, the authors proposed a method to produce an extremely high-purity silica contg. by the reaction between an aq. soln. of sodium silicate and mineral acid in the presence of a chelating agent and hydrogen peroxide.
Abstract: PURPOSE: To produce an extremely high-purity silica contg. ≤1ppm impurity metallic elements and ≤1ppb radioactive impurities from an aq. soln. of alkali silicate. CONSTITUTION: Silica is formed by the reaction between an aq. soln. of sodium silicate and mineral acid. In this case, silica is precipitated in the acidic region of ≥1N acid in the presence of a chelating agent and hydrogen peroxide, the precipitated silica is separated, recovered and washed with a mineral acid contg. the chelating agent and hydrogen peroxide, and a high-purity silica contg. ≤1ppm impurities of Al, B, Ba, Ca, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb, Sr, Ti, Zn and Zr and ≤1ppb impurities of U and Th is produced. COPYRIGHT: (C)1995,JPO

Patent
17 Mar 1994
TL;DR: In this paper, the authors present a method for treating glyceride oils to remove contaminants therefrom by adding solid alkali metal silicates, particularly sodium metasilicate pentahydrate and hydrous sodium polysilicate.
Abstract: The present invention provides a composition and method for treating edible glyceride oils to remove contaminants therefrom. The composition can be added directly to crude oil, degummed oil, or used oil to reduce free fatty acids, color bodies, trace metals, and other impurities. The composition comprises solid alkali metal silicate, particularly sodium metasilicate pentahydrate and hydrous sodium polysilicate. This material is added to oil in an amount approximately equal to the amount of free fatty acids present in the oil. The oil may then be heated and agitated. The oil is then filtered or centrifuged to remove the solid hydrous sodium silicate.

Patent
16 Jun 1994
TL;DR: In this article, a method for inhibiting dust emissions from hot (>150° F) substrates is provided which comprises adding to the substrate an aqueous solution of sodium silicate.
Abstract: Method for inhibiting dust emissions from hot (>150° F.) substrates are provided which comprise adding to the substrate an aqueous solution of sodium silicate.


Patent
22 Aug 1994
TL;DR: In this paper, a process for preparing a compacted, granular sodium silicate which withstands abrasive effects, for example mechanical conveying without damage having an SiO2/Na2O molar ratio of 1.7 : 1 to 4.1 : 1, by intimately mixing the sodium silicates having a median particle diameter of < 500 µm with a material increasing its hardness before converting it into pressed granules having particle sizes of 0.1 to 5 mm.
Abstract: The present invention relates to a process for preparing a compacted, granular sodium silicate which withstands abrasive effects, for example mechanical conveying without damage having an SiO2/Na2O molar ratio of 1.7 : 1 to 4.1 : 1, by first intimately mixing the sodium silicate having a median particle diameter of < 500 µm with a material increasing its hardness before converting it into pressed granules having particle sizes of 0.1 to 5 mm by compacting, comminution and screening.

Patent
29 Apr 1994
TL;DR: In this paper, a desiccant for HFC-32, HFC152a and blended refrigerants containing HFC 32 and HFC 152a is described, which is based on immersing formed articles of 3A type zeolite having 20 to 60% in ion equivalent weight of its sodium ions exchanged for potassium ions in an aqueous solution.
Abstract: A method for the production of a desiccant for HFC-32, HFC-152a and blended refrigerants containing HFC-32 and/or HFC-152a comprises immersing formed articles of 3A type zeolite having 20 to 60% in ion equivalent weight of its sodium ions exchanged for potassium ions in an aqueous solution of at least one member selected from the group consisting of sodium silicate and potassium silicate, thereby effecting deposition of SiO2 on the formed articles, removing the SiO2 -deposited formed articles from the aqueous solution, dehydrating the wet formed articles and subsequently activating the dehydrated formed articles. Also provided is a desiccant for HFC-32, HFC-152a and blended refrigerants containing HFC-32 and/or HFC-152a produced by this method.

Patent
04 Feb 1994
TL;DR: The improved method of making a frangible, biodegradable clay target includes forming a plastic mixture by uniformly blending together clay, water and binder wherein the binder consists of about 1-2 percent of sodium silicate and about 0-1 percent of dextrin, by weight of the mixture, the total concentration of binder not exceeding about 2 percent, by the mixture as discussed by the authors.
Abstract: The improved method of making a frangible, biodegradable clay target includes forming a plastic mixture by uniformly blending together clay, water and binder wherein the binder consists of about 1-2 percent of sodium silicate and about 0-1 percent of dextrin, by weight of the mixture, the total concentration of binder not exceeding about 2 percent, by weight of the mixture. The water is present in a concentration not in excess of 10 percent, by weight of the mixture and clay forms the remainder of the mixture. The mixture is charged into a forming press and hot pressed and dried at about 300°-400° F. to a finished, non-fired greenware frangible, biodegradable clay target. The improved composition is as set forth above.

Patent
28 Jun 1994
TL;DR: In this article, a small dose detergent composition containing from 10 % to 40 % of a crystalline stratiform sodium silicate, from 25 % to 65 percent of a surfactant, and less than 50 % of other builders and other alkaline materials is presented.
Abstract: A small dose detergent composition containing from 10 % to 40 % of a crystalline stratiform sodium silicate, from 25 % to 65 % of a surfactant, from 0 % to 20 % of a bleaching component, and less than 50 % of other builders and other alkaline materials, wherein the ratio R of crystalline stratiform sodium silicate to the sum of other builders and other alkaline materials is not less than 0.34. The composition provides a dosage of less than 25 g, preferably 14-21 g of detergent in a 30 liter wash.

Patent
26 Sep 1994
TL;DR: In this article, the hydrated silicic acid obtained by neutralizing a sodium silicate aq. soln. with mineral acid is provided with particle characteristics which is in a range of 250-350ml/100g of oil absorption amount, 4.0-6.0cc/g of total fine pore volume and 200-400a of average grain size.
Abstract: PURPOSE: To produce a hydrated silicic acid combining high fine pore volume with fine grain size. CONSTITUTION: In the hydrated silicic acid obtained by neutralizing a sodium silicate aq. soln. with mineral acid, the hydrated silicic acid is provided with particle characteristics which is in a range of 250-350ml/100g of oil absorption amount, 4.0-6.0cc/g of total fine pore volume and 200-400a of average fine pore diameter, and whose average grain size is in eigher range of 3.0-15μm by laser method measured value, 2.0-4.0μm by Coulter method measured value or 0.3-3.5μm by centrifugal sedimentation method measured value. This hydrated silicic acid is produced through the first process in which a mineral acid equal to 30-50% of neutralization equivalent is added at <=70 deg.C to the sodium silicate whose silica concn. is 6-10wt.% in terms of SiO2 and the mixture is subjected to wet grinding treatment by strong shearing during aging time, the second process in which total silica is precipitated by adding residual mineral oil and aging at the temp. higher than that of the preceding process and the third process in which the mineral acid is added to adjust a pH of slurry in a range of 5-3.

Patent
29 Aug 1994
TL;DR: In this article, the authors proposed a hardened strength-improving agent for improving the hardened strength of the cement components including an agent produced by thermally dissolving sodium hydroxide in silicic acid and subsequently adding the solution to the alkali ion aqueous solution of silicon dioxide and sodium oxide.
Abstract: PURPOSE: To enable to improve the hardened strength of cement components and reduce the amount of the used cement by coating the surfaces of the cement components with an aqueous solution produced by dissolving sodium silicate in an aqueous alkali ion solution. CONSTITUTION: The cement hardened strength-improving agent for improving the hardened strength of the cement components includes an agent produced by thermally dissolving sodium hydroxide in silicic acid and subsequently adding the solution to the alkali ion aqueous solution of silicon dioxide and sodium oxide, and an agent produced by thermally melting the mixture of quartz with sodium carbonate and subsequently dissolving the product in an alkali ion aqueous solution, in addition to the above-described agent. It is estimated that the sodium silicate contained in the agent for improving the hardening strength of the cement is reacted with the lime component of the cement to change the sodium silicate into glassy calcium silicate, thus improving the hardened strength of the cement. Further, since the surfaces of the cement components are covered with calcium silicate, a glassy substance, the hydration heat of the cement is shut therein to accelerate the curing action.

Patent
02 Nov 1994
TL;DR: A non-phosphate machine dishwashing detergent composition comprising at least 80 wt. % of a combination of alkaline carbonate, e.g., sodium carbonate and alkaline bicarbonate is presented in this article.
Abstract: A non-phosphate machine dishwashing detergent composition comprising at least about 80 wt. % of a combination of alkaline carbonate, e.g., sodium carbonate, and alkaline bicarbonate, e.g., sodium bicarbonate, having a weight ratio of carbonate to bicarbonate of about 1:1 to 1:5, about 0.5 to 8.0 wt. % of a polycarboxylate polymer consisting of polymaleic acid as dispersant, and about 0.5 to 8.0 wt. % of a nonionic surfactant. The composition may also contain an oxygen bleach, e.g., sodium perborate, and an alkali metal silicate corrosion inhibitor, e.g., sodium silicate, as well as other additives. Use of the composition results in relatively low residue formation on articles being washed.