Showing papers on "Sodium silicate published in 1993"

23Na NMR chemical shifts and local Na coordination environments in silicate crystals, melts and glasses

Abstract: In order to decipher information about the local coordination environments of Na in anhydrous silicates from 23Na nuclear magnetic resonance spectroscopy (NMR), we have collected 23Na magic angle spinning (MAS) NMR spectra on several sodium-bearing silicate and aluminosilicate crystals with known structures. These data, together with those from the literature, suggest that the 23Na isotropic chemical shift correlates well with both the Na coordination and the degree of polymerization (characterized by NBO/T) of the material. The presence of a dissimilar network modifier also affects the 23Na isotropic chemical shift. From these relations, we found that the average Na coordinations in sodium silicate and aluminosilicate liquids of a range of compositions at 1 bar are nearly constant at around 6–7. The average Na coordinations in glasses of similar compositions also vary little with Na content (degree of polymerization). However, limited data on ternary alkali silicate and aluminosilicate glasses seem to suggest that the introduction of another network-modifier, such as K or Cs, does cause variations in the average local Na coordination. Thus it appears that the average Na coordination environments in silicate glasses are more sensitive to the presence of other network-modifiers than to the variations in the topology of the silicate tetrahedral network. Further studies on silicate glasses containing mixed cations are necessary to confirm this conclusion.

Sodium and silver environments and ion-exchange processes in silicate and aluminosilicate glasses

Abstract: X-ray absorption fine structure (XAFS) was used to determine the local environments of sodium in sodium silicate and aluminosilicate glasses. Silver environments were also measured after Ag/Na ion exchange in the same glasses. Na-O distances were found at a characteristic first-shell distance of 2.30-2.32 A. The coordination number of approximately 5 oxygen in binary silicates dropped, however, when Al 2 O 3 was added to the glass. We ascribe this to changes in the geometry of available oxygen cages in the glass structure as nonbridging oxygens are replaced by bridging oxygens. In comparison, ion exchange with silver led to cation environments with much shorter cation-oxygen distances of 2.08-2.23 A and even smaller coordination numbers approaching 2 oxygen, resembling the immediate environment of Ag in Ag 2 O

Chapter 4 Commercial Preparation and Characterization of FCC Catalysts

Abstract: Publisher Summary This chapter describes the basic components of all present day Fluid Catalytic Cracking (FCC) catalysts. Without doubt, the most important component of the modem FCC catalyst is the zeolite. Three major synthetic techniques are used in the commercial preparation of zeolite Y for FCC. These techniques are sodium silicate based, precipitated-silica based, and clay based. Two commercial methods of synthesizing zeolite Y have been developed in which kaolin clay is the starting material. One case involves total conversion of the clay into zeolite, whereas the other requires only partial conversion. By far the most common material added to commercial FCC catalysts to accomplish heavy oil conversion is alumina in various forms and amounts. Alumina has long been used as an active support in reforming and hydrotreating catalysts. In FCC catalysts, some silica is included with the alumina either in the form of added silica (polysilicic acid), silica binder, or is present naturally in the clay based in situ process.

Adsorption of co2

Abstract: PURPOSE:To increase the adsorbing amount of CO2 and to adsorb CO2 on zeolite at relatively low temp CONSTITUTION:Zeolite is added to an aqueous solution containing a transition metal ion and the resulting dispersion is refluxed under heating to subject a metal in zeolite to the ion exchange with a transition metal to form a transition metal supported zeolite or sodium aluminate aqueous solution When this aqueous solution is reacted with a sodium silicate aqueous solution, transition metal supported zeolite A obtained by adding an aqueous solution of an inorg salt of a transition metal to a zeolite synthesizing mother liquid to react both of them is used as an adsorbent to be brought into contact with CO2 (-containing gas) at about 20-100 degC

Quantitative silicon‐29 NMR investigations of highly concentrated high‐ratio sodium silicate solutions

Abstract: In concentrated alkaline sodium silicate solutions a consistent decrease in the amount of silicate monomer Q0, end-groups Q1, cyclic trimer Q groups and middle groups Q2, and also branching groups in ring formations Q, is observed with increasing molar ratio of SiO2 to Na2O (RM), whereas for branching groups Q3 and cross-linking groups Q4 a consistent increase is found. The interest of this work is particularly focused on the Q4 region, which may indicate the formation of colloidal silicate particles. For this region the 29Si background signal from the NMR probe and the glass tube can cause problems, so the subtraction technique was used. Spin-lattice relaxation times, not previously reported for silicate solutions of concentrations and molar ratios as high as those studied here, are given for all structural units, including Q4. It was found that sodium silicate solutions of RM = 2.0 do contain a Q4 region when they are extremely highly concentrated in SiO2 (38 wt% SiO2) or aged.

Process for protecting a surface using silicate compounds

Abstract: A process for forming a protective layer (14) on a fixed surface (12) such as a fixed metal or wood surface, to provide protection against abrasion, corrosion, heat and fire. The process comprises first preparing the surface of the article. On metal articles, the surface can be prepared by cleaning the surface and then exposing the surface to concentrated phosphoric acid. On wood, the surface can be prepared by thoroughly cleaning the surface with hot water and detergent only. Preferably, the surface is prepared such that a uniform, continuous layer of liquid can be formed thereon. After the surface is prepared, a 10-16 % (v/v) silicate-containing solution is then applied for 20 seconds and allowed to dry completely at 305 DEG F to form a layer of silicate material (18) over the surface. During the drying process, at least a portion of the sodium silicate is converted into silicon dioxide. An acid is then applied to the surface to form the protective layer on the surface.

Continuous preparation of silica sols which contain large particles

Abstract: A process is provided for the preparation of aqueous silica sols having a particle size of 27 to 72 nm. by adding fresh acidic silica sol into the reactors of a multi stage cascade reactor wherein the reactors contain aqueous solution of colloidal silica sol of a pH of 8 or above. Each successive stage of the cascade reactor is supplied with overflow from the preceding stage. Alkaline compounds, such as alkaline sodium silicate solution, alkaline potassium silicate solution, sodium hydroxide solution or potassium hydroxide solution, are introduced into the first reactor or first reactors so that a pH value in the range of 8 to 12.5 is established in the reactors.

Water-based fire extinguishing agent

Abstract: PURPOSE: To provide a water-based fire extinguishing agent which is excellent in foaming and film making performance even in a low temperature area by combining perfluoroalkylbetaine and imida-zoliniumbetaine to be mixed at a specified rate into an aqueous solution which is blended selectively with one or more of potassium hydrogencarbonate and ammonia phosphate as principle materials of an extinguishing dhemical. CONSTITUTION: A foaming film making agent combining perfluoroal-kylbetaine and imidazoliniumbetaine is mixed into an aqueous solution containing an extinguishing agent selected from potassium bicarbonate and ammonia phosphate as principle materials at a rate of 0.1-1.5wt.% per total amount to make a water-based fire extinguishing agent with foaming film making peoperty improved in s low temperature range. Then, the agent is mixed with 0.5-1.5wt.% of rice vinegar for food. In addition, one or more selected from among triethanolaminelaurylate, diethanolamine-laurylate and terahydro 1, 4-oxazine is mixed into one or more selected from among sodium silicate, potassium silicate and tripotassium phosphate as saponification agent of fat and oil. COPYRIGHT: (C)1994,JPO&Japio

Composition for passivating vanadium in catalytic cracking and preparation thereof

Abstract: Disclosed is a vanadium trap for use in FCC which comprises a major amount of calcined kaolin clay, free magnesium oxide and an in situ formed magnesium silicate cement binder. Also disclosed are procedures for the preparation of the trap by forming a slurry in water of hydrous kaolin clay, magnesium oxide or magnesium hydroxide and sodium silicate, aging the slurry to form magnesium silicate in situ, optionally adding additional kaolin, colloidal silica or both, spray drying, and calcining the resulting spray dried microspheres without forming appreciable amounts of crystalline magnesium silicates or crystalline magnesium aluminates.

Atomic Force Microscopy and X‐ray Photoelectron Spectroscopy Investigation of the Onset of Reactions on Alkali Silicate Glass Surfaces

Abstract: Atomic force microscopy was used to measure forces acting on a sharp tungsten tip as it was brought into contact with silica and 30 mol% binary alkali silicate glasses. Experiments were performed in controlled atmospheres and under vacuum. Attractive forces and liquid-layer thicknesses were found to vary markedly between the glasses, and heterogeneity was observed on the binary alkali silicates analyzed in vacuo. Air or wet carbon dioxide exposure resulted in the penetration of the tip into a soft surface layer on the alkali silicates. In addition, the liquid layer formation on the alkali silicates was found to be promoted by exposure to water vapor in the order lithium < sodium < potassium. X-ray photoelectron spectroscopy indicated that reaction between the potassium silicate surface and water vapor occurred on exposure to only 10[sup [minus]4] torr (1 torr = 1.33 [times] 10[sup 2] Pa) water. Surface segregation and leaching of potassium occurred under the same conditions.

Method for stabilizing clay bearing soils by addition of silica and lime

Abstract: A method is shown for stabilizing clay bearing soils in which a silica compound is incorporated into the soils in addition to the application of lime. The silica compound can be either an amorphous, silica fume, a crystalline silica, a silica gel, sodium silicate, potassium silicate, finely ground glass or combinations thereof. The silicate compound promotes the formation of calcium silicate hydrates over the formation of calcium aluminate hydrates in the resulting pozzolanic reaction occurring in the clay bearing soils. The silica compound and lime can be incorporated into the soils in a single step.

Detergent bleach compositions containing layered silicate builder and percarbonate stabilized by EDDS

Abstract: Detergent compositions comprising ethylenediamine-N,N'-disuccinic acid or salts thereof, an alkali metal percarbonate bleach and a crystalline layered sodium silicate of formula LMSixO2xH.yH2O wherein L is an alkali metal, and M is sodium or hydrogen, x is a number from 1.9 to 4 and y is a number from 0 to 20 are provided. The compositions also preferably comprise additional non-phosphate detergent builder compounds.

Production of a type zeolite

Abstract: PURPOSE:To provide a method for producing an A type zeolite comprising spherical or round crystal particles and suitable as a builder for detergents, a synthetic adsorbing agent, a carrier for catalysts, etc. CONSTITUTION:In a method for obtaining a crystalline A type zeolite by depositing an amorphous aluminosilicate gel from a mixture solution containing a sodium aluminate aqueous solution, an ion-adjusting agent and a sodium silicate aqueous solution and subsequently crystallizing the gel by a hydrothermic synthetic reaction, the method is characterized by employing sodium chloride as the ion-adjusting agent and controlling the composition ratio of the mixture solution to a H2O/Na2O: SiO2/Al2O3: Na2O/SiO2: NaCl/H2O molar ratio of 9.9-120:0.8-2.5: 0.8-3.3:0.01-0.1.

Process for reinforcing a glass fiber attachment surface and article

Abstract: The invention relates to a process for adhesively bonding the surface of a humidity sensitive glass article by: (A) bringing the surface to be strengthened into contact with an aqueous solution of an acid and a silane; then (B) bringing the surface to be strengthened into contact with an alkaline aqueous solution of sodium silicate and/or potassium silicate; and (C) drying and hardening the coating applied on the surface of the glass as the result of steps (A) and (B). (D) Then adhesively bonding the glass article to another component to form a composite glass article. Application to the production of optical fiber couplers and composite lenses.

Method for bleaching kaolin clay

Abstract: An improved method for improving the brightness of clay of the type that is capable of being bleached by an oxidative reagent such as Georgia gray kaolin. Such clay, in the form of a dispersed slurry, is treated with a combination of sodium silicate, sodium hypochlorite and ozone, most preferably followed by magnetic purification and a reduction bleach. Sodium hypochlorite is added shortly before ozonation.

Soil stabilization process

Abstract: This invention is concerned with a soil stabilization process in which soil particles comprising the soil surfaces to be stabilized are contacted or treated with an aqueous solution of an alkali metal silicate, such as sodium silicate, and a carbonate reactant or gelling agent selected from the group consisting of an alkylene carbonate, such as ethylene carbonate, a polyester polycarbonate and mixtures thereof. This invention also relates to soil stabilized by admixture with (1) an aqueous solution of an alkali metal silicate and (2) the carbonate reactant.

Method for the quantification of silicon‐29 NMR spectra, developed for viscous silicate solutions

Abstract: A method is described for obtaining quantitative intensity data from solution-state spectra by a combination of coaxial tubes and sample replacement to take account of spectrometer electronic effects. The protocol was applied to two sodium silicate solutions of high silica content, and it is shown that there is no ‘invisible’ silica at the concentrations studied.

Catalytically inert particles for blending with petroleum cracking catalyst

Abstract: A method for converting attapulgite clay which has never been heat treated sufficiently to destroy the natural colloidal properties of the clay to attrition resistant, low surface area, essentially catalytically inert particles adapted for use as a blending agent with particles of active zeolitic cracking catalyst. The clay, preferably mixed with an alkaline cementitious material (such as, for example, portland cement or sodium silicate) is sintered at a temperature above 1350° F., preferably in the range of 1500° F. to 1800° F., to reduce surface area to a value below about 15 m 2 /g, preferably below 5 m 2 /g, and decrease apparent bulk density to a value below 1.1. The material is sized to form an essentially dustless, free flowing powder.

Aqueous heat-resistant paint and heat-resistant coating layer

Abstract: PURPOSE:To obtain a paint containing an alkali metal silicate and silicon dioxide powder at respective specific ratios, having extremely short drying and curing time and usable without necessitating baking process and, accordingly, enabling the forming of a heat-resistant coating layer in a short time at a reduced cost. CONSTITUTION:This paint contains (A) 7-20wt.% of an alkali metal silicate (e.g. sodium silicate) and (B) 5-30wt.% of silicon dioxide powder. The paint can be produced e.g. by diluting water glass with water to obtain an aqueous solution containing 25-35wt.% of the component A, adding 170-210wt.% of the component B based on the component A in the aqueous solution and stirring the obtained mixture. In the above process, the molar composition of the water glass is preferably R.nSiO2 (R is alkali metal oxide), the Si/Na ratio (n) is preferably 2-2.3 and the water glass preferably contains 35-38wt.% of SiO2 and 17-19wt.% of alkali metal oxide.

Antibacterial antifungal surface-treating agent composition

Abstract: PURPOSE: To provide a composition having effects such as antibacterial effect, antifungal effect and deodorant effect by dispersing inorganic wall microcapsules holding a stabilized chlorine dioxide solution therein in the aqueous solution or aqueous dispersion of a resin having a coating film-forming ability and having a pH within a specific range. CONSTITUTION: The antibacterial and antifungal surface-treating composition is obtained by mixing a sodium silicate aqueous solution with the hexane solution of a nonionic surfactant, a polyoxyethylene sorbitan trioleate, etc., emulsifying the mixture with a homogenizing mixer, adding and reacting an ammonium bicarbonate aqueous solution with the produced emulsion for 60min, centrifuging the reaction solution, charging the separated silica hollow particles in a flask, evacuating the flask with a vacuum pump, adding stabilized chlorine dioxide to the silica hollow particles in the state, dispersing the produced inorganic wall microcapsules holding the 0.1-5.0% stabilized chlorine dioxide solution having a pH of 8.0-12.0 therein in the aqueous solution or 5% aqueous dispersion of a resin (e.g. a vinyl chloride resin) having a pH of ≥7.0 and an ability to form coating films. COPYRIGHT: (C)1994,JPO&Japio

Solubility and water-softening properties of a crystalline layered sodium silicate, SKS-6

Abstract: The solubility and water-softening capabilities of a crystalline layered silicate, SKS-6 (Na2Si2O5), have been evaluated and compared with those of an amorphous silicate of similar composition. Both silicates readily broke down to yield amorphous silica on contact with aqueous solutions and were found to be appreciably soluble, even at 25 °C. The bulk of calcium and magnesium was precipitated from hard-water solutions as silicates and/or hydroxides within a few minutes of reaction. Magnesium was removed more effectively than calcium, owing to the lower solubility of the Mg-silicates. The amorphous silicate exhibits greater solubility, better magnesium removal and inferior calcium removal when compared to SKS-6. Solution-state NMR, solid-state NMR, X-ray powder diffraction and chemical analysis have been used to characterise the silicates in the solution and solid phases. The interactions between metal ions and silicates are discussed with reference to the observed results.

Mössbauer effect, electron spin resonance, and electrical conductivity studies of the effect of iron on the magnetic and electrical properties of sodium silicate glass

Abstract: Mossbauer effect, electron spin resonance, and electrical conductivity measurements were performed on a sodium silicate glass containing iron. The glass composition was (in mol%) 40SiO 2 , 60Na 2 O and 1-6Fe 2 O 3 . The amount of iron accomodated in different site positions was determined for each composition. The radial and angular distorsion parameters have been deduced from a calculation based on Newman's superposition model. A correlation between the behaviour of iron and the magnetic and electrical proporties was proposed

Process for the preparation of layered sodium silicates and use thereof

Abstract: To prepare crystalline sodium silicate having a layered structure and a molar SiO2:Na2O ratio of 1.9:1 to 20:1, sodium silicate essentially composed of delta -Na2Si2O5 is reacted with at least one acid in the pH range from 9 to 13 with stirring. The acids used can be carbon dioxide, sodium hydrogen carbonate, boric acid, sodium tetraborate, sulphuric acid, phosphoric acid, hydrochloric acid, alkanesulphonic acids, alkanecarboxylic acids and/or hydroxycarboxylic acids.