Showing papers on "Sodium silicate published in 1995"

Structural order in MCM-41 controlled by shifting silicate polymerization equilibrium

Abstract: Powder X-ray diffraction, 29Si and 129Xe NMR spectroscopy of MCM-41 show that the long-range structural order and textural uniformity of the mesoporous molecular sieve are markedly improved due to a shift in the reaction equilibrium when acetic acid is repeatedly added during the conversion of sodium silicate and NMe3(C16H33)Cl to a MCM-41 phase.

The oxygen coordination of metal ions in phosphate and silicate glasses studied by a combination of x-ray and neutron diffraction

Abstract: A combination of results from x-ray and neutron diffraction is used to obtain structural information about the metal-oxygen coordination shell in oxide glasses. Two ways to extract structural parameters of the Me-O coordination are presented. The first variant is a direct combination of both distance correlation functions which are considered simultanously in a least-squares fit procedure. On the other hand a suitable difference of the two structure factors is introduced, which do not contain any O-O correlation. The corresponding distance correlation function directly shows the Me-O peak. The samples are metaphosphate glasses with Me = Al, Zn, Mg, Ca, Ba and Na and two sodium silicate glasses (76.5 and 67 mol% silicon dioxide). Four oxygens are found in contact to the Mg ion. But two additional, more distant positions are detected. Thus, the sum of all oxygen atoms in the coordination sphere is 6 rather than 4. The Zn cation is located in a real ZnO4-tetrahedron. The number of oxygens in the environment of the Na ion is of about five both in the metaphosphate glass and in the silicate glasses. But a surprising result is a splitting observed for the Na-O distance peak in case of silicate glasses.

Silicate species exchange, viscosity, and crystallization in a low-silica melt: In situ high-temperature MAS NMR spectroscopy

Abstract: High-resolution, magic-angle-spinning (MAS), 29Si NMR spectra have been obtained for a sodium silicate glass and liquid (60 mol% Si02) to temperatures over 600 °C. Crystallization was monitored in situ, and motional averaging of the peaks for distinct silicate anionic species (Q2 and Q3 species) in the liquid was observed. Modeling of the spectra yielded species exchange frequencies. The inverses of these exchange frequencies are slightly longer than shear relaxation times calculated from bulk viscosity using the Maxwell relation; viscosities calculated from the NMR data using an Eyring model are close to, but slightly less than, measured viscosities. These results are similar to those obtained for Q3_ Q4 exchange in K2Si409 liquid, indicating that local Si-O bond breaking occurs on a time scale consistent with it being the primary control on viscous flow even in lower silica liq uids.

Bricks made of coal fly-ash and slag, cured in the open air

Abstract: Volume mass, compressive strength, water uptake and water absorption of pressed test samples made of a mixture of coal fly-ash, slag and sodium silicate solution (water-glass) were determined. It was found that such mixtures can solidify in the open air and form water-stable materials. The composition and structure of new formations for the binder and cured material itself were established using X-ray diffraction and a scanning electron microscope. The material has a high water uptake, which may be reduced using a number of different methods, the best of which is short-term impregnation with a hydrophobic material of the siloxane group. The water uptake and water absorption of compressed samples impregnated with such materials are similar to those of comparable building materials, such as lime-sand bricks, clay bricks or concrete blocks.

Insulation barrier and a method of making an insulation barrier

Abstract: The insulation barrier is formed of a body of foamed polystyrene, either expanded or extruded, which is provided with a protective coating formed of a metallic-based inorganic material and is applied over at least one surface of the body. Optionally, a fire resistant composition of any inorganic silicate, boric acid, any salts of boric acid, hydrated sodium borate (borax) or mixtures thereof, and preferably sodium silicate, is applied in solution form and maintained within the body by a wetting agent in the solution. The protective coating is being applied by a coating roller followed drying of the polystyrene body.

High temperature nuclear magnetic resonance studies of oxide melts

Abstract: Recently, application of in situ, high temperature nuclear magnetic resonance (NMR) spectroscopy to study silicate, borate and aluminate melts has lead to a variety of findings on structural changes with temperature (particularly in cation coordination number), and on the dynamics of exchange and diffusion. New data are presented on chemical shifts and spin-lattice relaxation of 23 Na in a number of silicate liquids to about 1200°C, and these results are discussed in light of other recent studies. These results clearly demonstrate the mixed alkali effect on cation motion. New high temperature magic angle spinning 11 B NMR spectra for a sodium borate liquid are also presented. As in previous studies of aluminate and silicate melts, the latter data set suggests that the mechanism of viscous flow is closely tied to local exchange of cationic species.

Strätlingite formation in high-alumina cement — zeolite systems

Abstract: Reaction mechanisms of strtitlingite formation in high-alumina cement (HAC)—zeolite systems were studied. A component separation method that made it possible to study individual reactions involving hydrated HAC and zeolite was employed. Different sodium salts, e.g. sodium silicate, sodium carbonate, sodium sulphate and sodium nitrate, were used to promote statlingite formation in the HAC paste. Strtitlingite forms preferentially to the cubic hydrogarnet phase in hydrated HAC systems in the presence of zeolite. A sufficiently high silicate concentration, arising from the dissolution of silicabearing materials such as zeolite, is required. A high pH environment is also conducive to stratlingite formation. The thermochemical stability of CAH10, the normal precursor to hydrogarnet formation, is apparently increased under the condition of high microsilica content.

Ion implantation into heated soda-lime glass substrates

Abstract: Soda-lime silicate glass substrates have been implanted with 55 keV copper, gallium and silver ions. For each ion, implants were done with the substrate at room temperature, 373, 498, 623 and 873 K. The ion distributions varied greatly with temperature. Ion exchange between the silver and sodium ions was observed for temperatures at 498 K and above; a similar process occurred for the copper at 873 K only. Those four implants formed single-mode enhanced-index waveguides. Migration of sodium and calcium ions was also observed: sodium was sputtered from the surface but, at 623 K and above, was replaced from within the bulk; conversely, at the same temperatures, the calcium at the surface migrated deeper into the glass. The calcium movement was induced by an electric field at the surface caused by the implantation process. The depletion of the sodium and calcium from the surface left a silica-rich layer. Overall the data emphasise that ion implantation into a heated multi-element silicate glass produces more complex changes than those predictable by normal ion-range theories.

Studies of NiO dissolved in alkali silicate melts based on redox potential and visible absorption spectra

Abstract: The redox behavior of Ni2+ ions in alkali silicate melts, xR2O · (1 - x)SiO2, (R = Na, K and Cs and x in the range 0.175 – 0.45), was investigated using linear sweep voltammetry and differential pulse polarography. The half-wave potential of Ni2+Ni0 depends on the alkali species and contents. It shifted to the positive side when the alkali species changed from sodium through potassium and cesium at a fixed ratio of alkali oxide to silica, indicating that NiO loses its thermodynamic stability in this order. Based on visible absorption spectra, it is shown that the Ni2+ ion exists in tetrahedral and octahedral coordinations in the alkali silicate glasses. The relative ratio of tetrahedral to octahedral species of Ni2+ also depends on the alkali species, and the content of the tetrahedral species of Ni2+ in potassium or cesium silicate is greater than that in sodium silicate. From these two results, it is assumed that, while NiO dissolves in the silicate melts as a weak base, some Ni2+ ions change into a tetrahedral coordination in a strongly basic solvent such as cesium silicate.

Co-granules and detergent tablets formed therefrom

Abstract: A homogenous co-granule comprising a salt of a di-, tri- or tetracarboxylic acid and an inorganic acid salt. The salt of a di-, tri- or tetracarboxylic acid is preferably an alkali metal citrate or an alkali metal oxydisuccinate. The inorganic salt is preferably alkali metal silicate, in particular sodium disilicate or sodium silicate with a composition satisfying SiO2 : Na2O = 1.0 - 3.3, ideally 1.8 - 2.3. The co-granule preferably also comprises at least one polymeric compound, being either acid and/or salt, selected from polycarboxylic acid and polypeptides. The invention also provides detergent compositions and tablets comprising these co-granules. The invention further provides the use of said detergent compositions and tablets in a mechanical dishwashing process.

Microwave susceptor comprising a dielectric silicate foam substrate coated with a microwave active coating

Abstract: The present invention provides a microwave silicate foam susceptor which comprises a dry sodium silicate foam substrate coated with an effective amount of microwave active material The silicate is preferably a sodium silicate, but can be other suitable alkali metal silicate, and the active constituent is preferably graphite, but other actives can be used The susceptor of the present invention is capable of quickly reaching and more importantly maintaining extremely high temperatures This enables it to brown and crispen foods in a microwave oven

Insulation barrier and a method of making and insulation barrier for a roof insulation system

Abstract: The insulation barrier is formed of a body of expanded polystyrene which is impregnated with sodium silicate. In addition, a coating formed of a metallic-based inorganic material is applied over at least one surface of the body. The sodium silicate is applied in solution form and maintained within the body by a wetting agent in the solution. The coating is be applied by a coating roller either before or after drying of the impregnated polystyrene body.

Alkaline manganese dioxide electrochemical cell having coated can treated with sodium silicate

Abstract: The performance characteristics of alkaline manganese dioxide cells are improved by applying a thin, polymeric coating to the inner surface of an unplated steel positive current collector, and treating the current collector with an aqueous solution of sodium silicate before or after the coating is applied to the inner surface. Silicic acid may also be added to the coating before its application to the inner surface of the current collector. In either embodiment of the invention, sodium silicate or silicic acid may also be added to the cathode mixture. The polymeric coating comprises, in combination, a first film forming binder component and a second component comprising an electrically conductive component such as carbon or a filler. The combination of the coating and the sodium silicate or silicic acid treatment of the current collector reduces the internal resistance of the cell, and may even be used on unplated steel.

Process for preparing silica-titania catalyst

Abstract: A process for preparing a silica-titania catalyst by adding an acidic solution containing a silicon compound such as sodium silicate and a titanium compound such as titanium sulfate dissolved therein to a solution of a compound such as ammonium bicarbonate to bring about co-precipitation, in which the acidic solution is a highly concentrated nitric acid-acidic or sulfuric acid-acidic solution, and a ratio of the dissolved titanium compound in the acidic solution is regulated in a certain range. According to this process, a catalyst capable of exerting a high performance in an esterification reaction and the like can be efficiently obtained.

Method of applying magnesium-rich calcium montmorillonite to skin for oil and organic compound sorption

Abstract: A method of increasing the bulk density and improving the water-dispersibility, oil sorption capacity, and body dirt and oil removability by compacting and/or shearing a magnesium rich calcium montmorillonite clay. In an optional embodiment of the present invention, silica gel, sodium silicate, acrylic polymers and copolymers, carboxy methyl cellulose, or other materials capable of providing lubricity to the surface of the clay crystals is added to the clay, prior to shearing, to enhance the compaction and/or shearing process and further increase the bulk density of the clay. The clay is sheared in an extruder, pug mill or California-type pellet mill when the clay includes about 20% to about 45%, preferably about 25% to about 40% by weight water, based on the dry weight of the clay.

A new route for the preparation of hydrated alkali-metal silicates

Abstract: The novel use of solid-state chemical reactions for the synthesis of layered alkali-metal silicates from sodium metasilicate and silica has been investigated. Reactions were carried out using a conventional laboratory muffle furnace. Sodium octosilicate, kanemite and magadiite were obtained as pure phases, by controlling the reaction temperature between 50 and 800 °C. Magadiite is best prepared at temperatures below 200 °C, octosilicate at temperatures between 400 and 500 °C, and kanemite at temperatures between 600 and 800 °C. The purest products were obtained from equimolar mixtures of metasilicate and silica powders, which were carefully ground together. The new method yields materials with crystal morphologies very similar to those previously described; however, it offers significant practical advantages over other published procedures, which typically involve long hydrothermal crystallizations, at high pH and high temperatures.

Lubricant composition for high-temperature working and its usage

Abstract: PROBLEM TO BE SOLVED: To obtain a nongraphitic lubricant composition for high-temperature working, having excellent lubricity without causing the carburizing or phosphorating and capable of preventing scratches from occurring due to a substrate. SOLUTION: This lubricant composition for high-temperature working is obtained by blending one or more particulate oxide-based layer materials selected from potassium tetrasilicic mica, sodium tetrasilicic mica, natural phlogopite, bentonite, montmorillonite and vermiculite with one or more binders selected from boron oxide, boric acid, an alkali metallic borate, sodium carbonate, potassium carbonate and sodium silicate or potassium silicate having <=100 deg.C melting point at (1:4) to (1:1) weight ratio of the particulate oxide-based layer materials to the binders. The lubricant composition for high-temperature working is used by dispersing and dissolving the composition in water at 20-80 weight ratio.

Liquid composition emitting far infrared rays and method for preparation thereof

Abstract: A liquid (ionized) composition emitting far infrared rays and a method for preparation thereof which can be used for a variety of applications is disclosed. The composition is prepared according to a preparing method, comprising the steps of: dissolving sodium silicate, sodium aluminate, sodium oxide, sodium thiosulfate, germanium dioxide, and highly pure white sugar at a temperature of 20° to 40 °C and mixing the dissolved solutions to resultingly prepare a first solution; adding a second solution made by ionizing gold to chloroauric acid and a third solution made by ionizing silver nitrate to silver thiosulfate to the first solution; and maintaining the resultant mixture at ordinary temperature (15° to 25 °C) for 48 to 72 hours. The highly pure white sugar of the first solution in the composition may further comprise an aqueous potassium carbonate solution added therein.

Production of polyurethane foam

Abstract: PROBLEM TO BE SOLVED: To make it possible to obtain the subject foam, excellent in mechanical properties and stainless steel corrosion resistance and useful as a heat insulating covering material, etc., by carrying out a reaction using a solution containing anhydrous sodium silicate dispersed in a specific ester compound. SOLUTION: (B) A polyol and (C) water are reacted with (D) an isocyanate in the presence of (A) a solution containing (A1 ) anhydrous sodium silicate dispersed in (A2 ) an ester compound which is a phthalic acid ester or an adipic acid ester (e.g. the one having 250-530 molecular weight, concretely dibutyl phthalate, bi-n-butyl adipate, etc.) [e.g. the one at 30-80wt.% concretration of the component A1 based on the total weight of the components A1 and A2 ] The reaction is preferably carried out by using the component A1 in an amount so as to provide 1-15wt.% based on the total weight of the components A, B, C and D.

Mesoporous metallosilicate and its production

Abstract: PROBLEM TO BE SOLVED: To obtain a mesoporous metallosilicate provided with a mesopore structure having uniform fine pore diameter distribution, small in Na content and large in specific surface area and to provide the producing method. SOLUTION: This mesoporous metallosilicate is a porous metallosilicate (except aluminosilicate) obtained by firing a composite material basing on an active silica, a metallic salt and a cationic surfactant, has the mesopore structure 10-100Å in average fine pore diameter and >=400m /g in BET specific surface area. A 1st process for preparing the active silica by bringing a sodium silicate aq. solution into contact with the cationic surfactant, a 2nd process for forming the composite material of the silica, the metal salt and the surfactant by adding a water soluble metallic salt (except Al salt) in a step for mixing the active silica with the cationic surfactant to react with each other in an alkaline region and a 3rd process for firing the composite material are performed in the order.

Composite silicate materials

Abstract: The present invention discloses a crystalline hydrated layered sodium silicate/amorphous sodium silicate composite material with predetermined hardness ion sequestration properties achieved by control of the process for forming the material, and a process for making the material. The process for producing the crystalline hydrated layered sodium silicate/amorphous sodium silicate composite comprises producing a crystalline sodium disilicate by heating a sodium silicate for a specified time at a specified temperature. The resulting material may include amorphous material, and the crystalline sodium disilicate can be either alpha-phase or delta-phase disilicate. This crystalline sodium disilicate is then hydrolyzed with up to 50 milliequivalents per gram of either H3O+ ions or OH- ions. The resulting material can sequester Ca2+ ions, Mg2+ ions, or both, depending on the starting materials used, processing conditions, and results desired.

Study of water repellent effect of earth substrates impregnated with water-based silicones

Abstract: As part of a study to assess the efficacy of impregnation for masonry materials, the impregnation of earth substrates with soluble sodium silicate followed by water-based silane/siloxane emulsion was investigated. The treatment was found to be successful in achieving water repellent and consolidation effects for the earth substrates. The water repellent effect is developed by the silane/siloxane emulsion which forms a polysiloxane thin film on the capillary wall surface through siloxane bonds. The water repellent effect is greatly enhanced by pre-impregnation with the silicate. The consolidation of the earth substrate by soluble sodium silicate is caused by the silicate gel formed by crosslinking with the substrate. The water repellent and consolidation effects in the earth substrates have been studied by using water absorption tests and FTIR examination.

Silicate species exchange, viscosity, and crystallization in a low-silica melt: In situ high-temperature MAS NMR spectroscopy

Abstract: High-resolution, magic-angle-spinning (MAS), ,rsi NMR spectra have been obtained for a sodium silicate glass and liquid (60 mo10/o SiOr) to temperatures over 600'C. Crystallization was monitored in situ, and motional averaging of the peaks for distinct silicate anionic species (Q, and Q3 species) in the liquid was observed. Modeling of the spectra yielded species exchange frequencies. The inverses ofthese exchange frequencies are slightly longer than shear relaxation times calculated from bulk viscosity using the Maxwell relation; viscosities calculated from the NMR data using an Eyring model are close to, but slightly less than, measured viscosities. These results are similar to those obtained for QtQo exchange in KrSioOn liquid, indicating that local Si-O bond breaking occurs on a time scale consistent with it being the primary control on viscous flow even in lower silica liquids.

Method of making a pigment based on calcium carbonate and silicium dioxide usable as filler for paper

Abstract: The invention relates to a method for preparing a mixed pigment of calcium carbonate and silica, useful as a filler for paper In accordance with the method, lime milk and an aqueous sodium silicate solution are admixed and the temperature of the mixture is raised to 55-170 DEG C, and thereafter carbon dioxide is supplied to the mixture until the pH of the mixture falls to 7 or below, thus precipitating a mixed pigment comprising calcium carbonate and silica

Sterilizing washing powder without phosphorous and its preparing method

Abstract: The phosphate-free diinfection detergent uses 0.5-4% polycarboxylte and 6-20% sodium silicate instead of phosphate; sodium silicate, sodium ethyloic cellulose, sodium carbonate, sodium bicarbonate and sodium sulfate are mixed homogeneously, dissolved in 70.5-90 deg.C deionized water or distilled water to form a 0.2-% concentration solution, then mixed with biguanide disinfectant water solution containing surface active agent. As compared ith common detergent, the effect of disinfection increases by a factor of 2-4.

Fire resistant glass unit

Abstract: Flame retardant glass has two panes arranged at a distance from each other, where the flame-sided pane is a glass pane and a foamed intermediate layer is arranged in the space between the panes. The intermediate layer is made of sodium silicate glass and water and has an additive increasing the resistance time in the case of a fire, which is displaced with multivalent alcohols and/or sugars. The novelty is that the sodium silicate glass as additive to the intermediate layer to suppress the sensitivity of the intermediate layer towards UV radiation is chosen so that there is no more sensitivity towards UV light.

Silicon dioxide for stabilizing beer and its production

Abstract: PURPOSE: To obtain silicon dioxide for stabilizing beer, which give excellent stabilizing effect without dajnaging the foam property of the beer. CONSTITUTION: Silicon dioxide for stabilizing the beer, which has 500-800m /g specific surface area by BET method, shows pH8.0-9.3 in 5wt.% aq. suspension, is in acid quantity, is obtained by adding simultaneously sodium silicate and a mineral acid into a salt aq. solution under stirring to allow to react with each other at pH3.0-7.0 and 80 deg.C, adjusting the pH of the resulting silica suspension to 3.0-7.0, filtering, washing and dispersing again the resulting silica hydrogel into water and after adjusting the pH to 5.5-8.5, filtering, washing and drying.