Showing papers on "Sodium silicate published in 1990"

The structure of sodium silicate glass

Abstract: Atomistic scale computer simulations can provide a more detailed understanding of the structure of glasses. Our results on sodium silicate glasses show that sodium ions are associated with nonbridging oxygens and that the sodium ions and nonbridging oxygens tend to aggregate to form silica rich regions and alkali rich regions. Interatomic distances of our simulated glasses are in good agreement with experimental results. O–Si–O bond angles are centered around 109° with narrow distributions. Si–O–Si bond angles are broadly distributed from 120° to 180° with an average of about 153°.

Bond ordering in silicate glasses: a critique and a re-solution

Abstract: The application of a standard thermodynamic model, the quasi-chemical approximation, to the problem of the arrangement of non-bridging atoms in alkali silicate glass is described. It is shown that this model gives a description of this arrangement in terms of disproportionation equilibria, the equilibrium constants being in the form of Boltzmann factors ΔE/kT. ΔE is due to interactions between bridging and non-bridging oxygen atoms. Fits to NMR data give values of ΔE/kT which are independent of composition and have the following values in alkali silicate glasses: 1.5 ± 0.5 (Li); 2.5 ± 0.5 (Na); ∼ 3 (Rb, Cs). Sodium silicate data allow one to identify T with the glass transition temperature and show that the values derived from structural data using the present model are consistent with soda activities and standard thermodynamic data. Finally, an origin is suggested for this ordering energy and the models of entropy used by other authors are critically discussed.

Method for preparation of sodium silicates

Abstract: For the preparation of crystalline sodium silicates having a layer structure, an SiO2/Na2O molar ratio of (1.9 to 2.1):1 and a water content of less than 0.3% by weight from a waterglass solution obtained by reacting sand with sodium hydroxide solution in an SiO2/Na2O molar ratio of (2.0 to 2.3):1 and having a solids content of at least 20% by weight, the waterglass solution is treated in a spray-drying zone with hot air at 200 to 300 DEG C to form a pulverulent, amorphous sodium silicate having a water content (determined as loss on ignition at 700 DEG C) of 15 to 23% by weight. The pulverulent, amorphous, water-containing sodium silicate is first ground, preferably to grain sizes of 1 to 50 mu m, before it is introduced into a rotary kiln in an inclined arrangement and treated therein with flue gas in countercurrent at temperatures of more than 500 to 850 DEG C, to form crystalline sodium silicate. The sodium silicate emerging from the rotary kiln is first comminuted to grain sizes of 0.1 to 12 mm and finally ground to grain sizes of 2 to 400 mu m.

Thermal insulating material based on pigment containing silica aerogels

Abstract: A thermal insulating material based on a pigment-containing silica aerogel is obtainable by a) reacting an aqueous dispersion of sodium silicate and a pigment with a strong acid or sodium silicate with a pigment-containing strong acid to give a pigment-containing silica hydrogen, the pigment being such that it scatters, absorbs or reflects infrared radiation of wavelength 3-10 μm, b) substantially freeing the resulting pigment-containing silica hydrogel from ionic constituents by washing with water, c) displacing the water in the hydrogen by a low-boiling liquid which is inert toward the pigment-containing silica gel, d) heating the liquid-containing silica gel thus obtained under supercritical conditions while completely covered with the liquid, and e) subsequently removing the liquid from the solid by flash vaporization at supercritical temperature

The connectivity of silicon sites in silicate glasses, as determined by two-dimensional 29Si nuclear magnetic resonance spectroscopy☆

Abstract: The application of two-dimensional silicon-29 homonuclear shift correlated magic angle spinning nuclear magnetic resonance (COSY MAS NMR) spectroscopy to silicate glasses prepared using silica isotopically enriched in silicon-29 is reported. Two sodium silicate glass compositions and a sodium phospho-silicate glass were examined. The results suggest that a substantial proportion of the four coordinate silicate sites in sodium silicate glasses Q2/Q3 and Q3/Q4 are interconnected on a nearest neighbor level. Experiments with the sodium silicate glasses prepared with varying levels of isotopic enrichment reveal a correlation between the intensity of the cross peak and the percentage of silicon-29 in the sample, confirming this observation. No cross peaks were observed for the sodium phospho-silicate glass, implying that the Q4 and six coordinate silicate sites present are not linked together at the nearest neighbor level.

Process for improving the physical and catalytic properties of a fluid cracking catalyst

Abstract: A process for significantly improving the physical and catalytic properties of fluid cracking catalysts (FCC) is disclosed. The invention is a process for manufacturing a fluid cracking catalyst. The process includes adding an effective amount of an acid stable surfactant or an alkaline stable surfactant to a slurry of clay particles and sodium silicate particles. The process then includes forming a sol binder and spray drying the particles. Forming of the dried particles into a catalyst product then occurs.

The system Na2O-CaO-SiO2-H2O

Abstract: A portion of the quaternary phase diagram for Na2O-CaO-SiO2-H2O has been constructed. Plotting concentrations as their 10th roots allows compounds having solubilities which differ by several orders of magnitude to be represented on a single diagram. The compositional relationships among sodium-substituted calcium silicate hydrate, calcium-substituted sodium silicate hydrate, calcium bydroxide, a quaternary compound of approximate composition 0.25Na2O · CaO · SiO2· 3H2O, sodium hydroxide monohydrate, and miscellaneous sodium silicate hydrates are presented. The quaternary diagram constructed shows the quaternary compound to exist in equilibrium with sodium-substituted calcium silicate hydrate and calcium hydroxide. Conditions in concrete pore solutions which favor the formation of this quaternary compound may also favor the occurrence of the alkali-silica reaction.

Thin silica flakes and method of making

Abstract: Hydrated sodium silicate particles can be expanded by heat to form thin-walled bubbles that can be broken, neutralized, washed and dried to provide hydrated silica flakes. These flakes can be mixed with non-swelling sorptive particles such as TLC grade silica and used to make chromatographic articles. One such article is a composite of a poly(tetrafluoroethylene) fibril matrix in which those particles and hydrated or fired silica flakes are enmeshed. The hydrated silica flakes can be fired to a refractory state and then incorporated into protective coatings to enhance their resistance to abrasion while also better protecting the coated substrates from corrosion.

Role of sodium silicate in phosphate flotation

Abstract: The role of sodium silicate in the anionic flotation of a Floridaphosphate ore was investigated using laboratory continuous flotation tests, frothability tests and SEM observations. In the absence of sodium silicate, Ca++ promoted the unwanted activation of quartz by forming calcium bearing precipitates. The addition of sodium silicate enhanced the flotation efficiency through:

Process for hydrothermal production of sodium silicate solutions

Abstract: The direct hydrothermal production of high purity sodium silicate solutions having a high SiO 2 : Na 2 O molar ratio by reaction of a silicon dioxide source with aqueous sodium hydroxide solutions, or with aqueous sodium silicate solutions having a lower SiO 2 : Na 2 O molar ratio, is made possible by using a silicon dioxide source that contains a sufficient fraction of cristobalite phase, or by conditioning other crystalline forms of silicon dioxide by heating at or above 1100° C., but below the melting point of silica, before the hydrothermal treatment. Preferably the sodium hydroxide solution has a concentration range of 10 to 50% by weight, and the reaction is carried out in a closed pressure reactor at temperatures of 150° to 300° C. and under saturated steam pressures corresponding to those temperatures.

Ultra high zeolite content FCC catalysts and method for making same from microspheres composed of a mixture of calcined kaolin clays

Abstract: A method for increasing the zeolite content of high zeolite content clay derived microspheres obtained by reacting porous precursor microspheres with a sodium silicate solution in the presence of seeds to crystallize zeolite Y in situ in macropores of precursor microspheres composed of a mixture of metakaolin and kaolin calcined to undergo the exotherm. The increased zeolite content is achieved by increasing macroporosity of the precursor microspheres and increasing the content of metakaolin in the precursor microspheres. The increase in zeolite is associated with an increase in catalytic activity and unexpectedly improved selectivity.

Method of making thin silica flakes

Abstract: Hydrated sodium silicate particles can be expanded by heat to form thin-walled bubbles that can be broken, neutralized, washed and dried to provide hydrated silica flakes. These flakes can be mixed with non-swelling sorptive particles such as TLC grade silica and used to make chromatographic articles. One such article is a composite of a poly(tetrafluoroethylene) fibril matrix in which those particles and hydrated or fired silica flakes are enmeshed. The hydrated silica flakes can be fired to a refractory state and then incorporated into protective coatings to enhance their resistance to abrasion while also better protecting the coated substrates from corrosion.

A High Temperature(1200 °C) Probe for NMR Experiments and Its Application to Silicate Melts

Abstract: A high temperature NMR probe was developed and applied to the measurement of 29Si nucleus in sodium silicate glasses and melts. The highest temperature attained was 1200 °C. The observed 29Si NMR spectra show narrowing above the glass transition temperature, due to the increase of the rate for exchange reaction among various structural species constructing the network structure.

Fire retardant insulation spray coating method

Abstract: The use of a liquid mixture of a liquid alkali-metal silicate preferably sodium or potassium silicate and more preferably sodium silicate with an inert mineral filler selected from perilite and vermiculite, suitably in an amount from 5 to 50% by weight and a mineral powder suitably selected from aluminum trihydrate and Wollastonite in an amount such as to intumesce with said silicate and to form a non-porous ceramic coating when subject to fire and suitably in an amount from 2 to 25% by weight for the protection of steel beams and columns against twisting due to fire. The formation of such coating both insulates and protects the steel beam or column from the heat from said fire. Suitably the thickness of the coating is at least two inches and is preferably from 2 to 4 inches to achieve the protection.

Preparation of silica sols

Abstract: A low metals, very high purity Silica Sol having very low content of Fe, Al, Na, K, and other metals can be manufactured using a complexation technique with oxalic acid in the starting sodium silicate solution. This complex is then removed by passage through anion exchange resins while other impurities are removed by passage through cation exchange resins. The Silica Sols obtained can have less than 50 ppm each of Fe, Al, Na, and K, based on totals SiO₂.

Liquid detergent composition for use in automatic dishwasher

Abstract: PURPOSE:To obtain the title composition which has good detergency and scale adhesion-eliminating effect and causes no corrosion to aluminum tablewares and a glass on the surface by compounding each a predetermined amount of NaOH or KOH, a silicic acid salt, a polyacrylic acid salt, an aminopolycarboxylic acid salt and water CONSTITUTION:The title composition comprises less than 05wt% NaOH or KOH, 7-11wt% (based on SiO2) silicic acid salt (eg sodium silicate), 1-5wt% acrylic acid salt (eg polysodium acrylate), 1-10wt% aminopolycarboxylic acid salt (eg ethylenediamineteraacetate) and the balance of water

Cement-containing catalyst composition and process for its preparation

Abstract: A solid composition is prepared by mixing water, a hydraulic cement, sodium silicate, and a catalyst composition comprising (a) an inorganic support, (b) Pt and/or Pd metal and (c) Fe metal and/or oxide, followed by maintaining the obtained mixture under such conditions as to affect hardening of the hydraulic cement. Preferably, the hydraulic cement is a Type III portland cement and/or a Class H well cement. A solid composition comprising hydraulic cement, sodium silicate and the above-described catalyst composition is provided. This solid composition can be used as a CO oxidation catalyst.

Polymerization of hydrolysis products of methyltriethoxysilane in aqueous solutions

Abstract: The structure and distribution of chemical species of hydrolysis and polycondensation products of methyltriethoxysilane in aqueous solutions containing sodium ions have been studied with the trimethylsilylation technique and by 29 Si n.m.r. spectroscopy. 11 trimethylsilylated derivatives of the products were obtained from the solutions. The recovery of methyltrisilanol (CH 3 Si(OH) 3 was much higher than that of the monosilicic acid in an aqueous sodium silicate solution at the same Si concentration and the same sodium ion-to-silicon molar ratio, suggesting that the polymerization of silicate anions is easier than that of hydrolysis products of methyltriethoxysilane in aqueous solutions. On the basis of the distribution, assignment of 29 Si n.m.r. peaks corresponding to low-molecular weight species formed from methyltriethoxysilane has been discussed

Low phosphorus containing detergent powders and process for preparing them: surfactant, aluminosilicate, sodium silicate and polyacrylate

Abstract: Low or zero-P detergent powders are prepared by a process in which sodium aluminosilicate, a polymeric powder structurant and other components are slurried and spray-dried, and particulate sodium silicate of defined characteristics is postdosed.

29Si NMR studies of the transformation of silicate anions in the system Na2O•SiO2•nH2O (n=9, 5) in crystals, melts, and solution

Abstract: A combined solid- and liquid-state 29Si NMR study shows that the monomeric silicate anions of crystalline sodium silicate hydrates Na2H2SiO4·nH2O (n= 8,4) upon melting undergo rapid condensation to distinct oligomer species, and that recrystallization of the melt involves hydrolysis of the oligomers and reconstitution of the initial monomeric silicate structure.

X-type zeolite molded body and its production

Abstract: PURPOSE: To easily obtain the molded body having a high content of X-type zeolite by adding a specified amt. of kaolinic clay to a synthetic X-type zeolite powder, extrusion-molding the mixture, calcining the molded body, bringing the calcined body into contact with a soln. contg. specified amts. of NaOH and sodium silicate and then dehydrating the body. CONSTITUTION: Kaolinic clay is added to a synthetic X-type zeolite powder by 10-40wt.% based on the clay plus powder. The mixture is then extrusion- molded, and the molded body is calcined. The calcined body is brought into contact with a soln. contg. 1-3mol/l of sodium hydroxide and the sodium silicate in the amt. to control the molar ratio of Na 2 SiO 3 to the Al in the clay to 0.2-2, and the clay is converted to X-type zeolite. The product is then dehydrated to obtain an X-type zeolite molded body contg. ≥90wt.% of the X-type zeolite. COPYRIGHT: (C)1991,JPO&Japio

Production of swelling synthetic hectolite-type clay mineral

Abstract: PURPOSE:To obtain the subject swelling synthetic saponite-type clay mineral having excellent transparency, water-swelling property and thickening speed by the hydrothermal treatment of a uniform suspension composition containing basic Mg, an SiO2-Na component and Al2O3-Na component at specific ratios. CONSTITUTION:The above saponite-type clay mineral containing metal components essentially consisting of Mg, SiO2, Na and Li, having the composition expressed by formula and belonging to a 3-octahedral smectite clay mineral is produced by the following process. A homogeneous suspension composition containing basic Mg, sodium silicate, a combination of sodium silicate and amorphous SiO2, etc., and an Al2O3-Na component containing sodium aluminate, etc., at compositional ratios shown in the formula is prepared beforehand. The composition is charged in an autoclave especially at pH8.5-10 in a state of aqueous slurry and subjected to hydrothermal treatment under a relatively mild condition compared with conventional process, i.e., at 100-300 deg.C under a pressure of 0-100kg/cm -G to obtain the objective swelling synthetic saponite- type clay mineral.

Surface treatment with corrosion and heat resistant coating film

Abstract: PURPOSE:To prepare a mixed soln. for forming a heat and corrosion resistant coating film on the surface of a metal by dissolving a transition element in a mixed soln. contg. alum and yttrium and by mixing the resulting soln. with a sodium silicate soln. CONSTITUTION:Alum powder is mixed with yttrium powder and dissolved in warm water and a transition element such as cobalt or nickel is further dissolved to prepare a mixed soln. (A). Crystalline titanium sulfate is dissolved in two or more kinds of compd. solns. selected among a sodium silicate soln., a potassium carbonate soln. and a boric acid soln. and the pH of the resulting soln. is adjusted to =10 with the soln.(A) as an adjusting soln. is applied to the surface of a metal such as iron, aluminum or zinc. A protective film having superior corrosion and heat resistances is formed on the metal.

Heat-Insulating, High-Temperature Materials on Cenosphere Base

Abstract: Cenospheres (microspheres) are silica-alumina fly ash lightweight fractions obtained from burning pulverized coal. These fractions are characterized by spherical particle shapes of 40 to 400 μm diameter (apparent bulk density 400 kg/m 3 ). The thermal-insulation properties of microspheres are useful. A binder that ensures good strength and improves thermal-insulation properties of bonded materials is hydrated sodium silicate. These microsphere materials are characterized by: (a) apparent bulk density in the compressed state from 400 to 500 kg/m 3 , (b) compressive strength up to 6 MPa, (c) average mean heat capacity of 500 kJ/m 3 K at temperatures from 298 to 993 K, and (d) thermal conductivity in the range 0.13 to 0.38 W/mK at temperatures from 298 to 1273 K. The investigation made it possible to optimize the material composition for particular applications. Microsphere materials with silicate binders can be used in the building industry, in heating equipment, and in metallurgical and foundry work.

A liquid non-phosphate detergent of high alkalinity

Abstract: A detergent concentrate suitable for the preparation of liquid, concentrated stock solutions comprising (A) 5 to 20% by weight nonionic surfactants, of which (A1) 4 to 20% by weight comprises alkyl glucosides corresponding to the formula R-O-Gx and (A2) 0 to 2% by weight C12-18 alkyl polyglycol ethers containing 5 to 9 ethylene oxide groups, (B1) 4 to 20% by weight sodium hydroxide, (B2) 0.5 to 12% by weight sodium silicate Na2O : SiO2 = 1:1 to 1:3.4, (B3) 2 to 12% by weight sodium nitrilotriacetate and 0 to 3% by weight of at least one phosphonic acid in the form of the sodium salt, in the formula R-O-GX, R is a C8-14 alkyl radical, G is a glucose residue and the index x is a number of 1.2 to 5. The sum of the constituents (B3) and (B4) is 3 to 12% by weight.