Showing papers on "Silicic acid published in 1983"

Aqueous curable molding compositions based on inorganic ingredients and process for the production of molded parts

Abstract: Molded parts having high flexural strength, based on alkali silicates, can be produced by casting and/or press-molding and curing by heating from aqueous molding compositions which are prepared from an oxide mixture containing amorphous silicic acid and aluminum oxide, as well as, optionally, as an additional component, aqueous, amorphous, disperse-powdery silicic acid, dissolved SiO2, and alkali from alkali silicate solutions, optionally alkali hydroxide or its aqueous solutions and, if desired, fillers, by means of mixing under agitation. By addition of a blowing agent inorganic foamed products can be obtained.

Diatom mineralization of silicic acid. vi. the effects of microtubule inhibitors on silicic acid metabolism in navicula saprophila1

Abstract: The role of microtubules in silicon metabolism leading to valve formation was investigated in the pennate diatom Navicula saprophila Lange-Bertalot & Bonik. By using synchronized cells blocked after mitosis and cytokinesis but prior to cell wall formation, effects due to inhibition of mitosis were eliminated. Cells were treated with three anti-microtubule drugs to assess the role of microtubules. Chemical analogs to two of the drugs provided controls for inhibition not related to microtubule disruption. Although all three anti-microtubule drugs reduced cell separation at high concentrations (1 × 10−3 M), podophyllotoxin was the only drug which reduced cell separation at concentrations lower than 1 × 10−5 M. None of the drugs at any concentration tested affected cell viability. There was no differential inhibitory effect between the active and inactive drugs on silicic acid transport, total uptake, incorporation, or pool formation. There was no qualitative difference between silica incorporated in treated and untreated cells. A colchicine binding component was isolated from N. saprophila. The characteristics of colchicine binding suggest this component may be tubulin. Microtubules do not appear to be involved in any of the steps of silicon metabolism leading to valve formation and yet they have profound influence on the symmetry and pattern of the mineralized product, the siliceous valve.

29Si NMR-Untersuchungen an Polykieselsäureestern

Abstract: Linear and branched siloxanes were prepared by partial hydrolysis of silicon tetrachloride and by esterification of the products of hydrolysation with methyl and ethyl nitrite. 29Si NMR spectra made it possible to distinguish between the isomers of each oligomer up to the heptamer. Linear relationships between the 29Si chemical shifts of the ethyl and the methyl esters on one hand and between the ethyl esters and the poly(silicic acid)s on the other hand were observed. However, due to the different effect of neighboring building units, there are only poor relationships between the 29Si data of the esters and the chloro derivatives.

Fertilizer product with sustained action and process therefor

Abstract: A fertilizer product in granular form with sustained action is provided by spraying a silicate-based solution on the surface of the fertilizer granules in a conventional coating machine which is maintained at temperatures ranging from 20° to 100° C. The coating solution comprises 1 to 50% by weight of a silicate and/or silicic acid ester based on the weight of the fertilizer material to be treated, 0.001 to 1.0 part by weight of a metal and/or non-aqueous metallic compound (first additives), 0.001 to 1.0 part by weight of an aqueous metallic compound (second additives), 0.001 to 1.0 part by weight of an inorganic mineral (third additives), and optionally high molecular weight organic compound, wherein all parts described above are based on the weight of the silicate and/or silicic acid ester used. The coated fertilizer granules are subject to heat-treatment for 10 seconds to 10 days under conditions that the relative humidity and the temperature be maintained at 5 to 95% and 10° to 250° C., respectively.

Formation of silica microplates by freezing dilute silicic acid solutions

Abstract: Formation of noncrystalline silica flakes (1, 2) and fibers (3) by freezing silicic acid sols and gels (0.1-1 M Si02) has been studied. This phenomenon is interesting from both the inorganic and geochemical viewpoints although the data on the products formed by freezing dilute silicic acid solutions are not available in the literature. We froze and thawed monomeric silicic acid solutions (0.05-2 mM) and observed the formation of polygonal, circular, elliptical, and annular silica microplates with diameters of 0.5 to 20 ,μm. The circular, elliptical, and annular microplates were similar to laminar opaline silica (LOS) in soils (4-7), suggesting that soil LOS can be formed when the soil solution containing silicic acid is frozen.

Binding of silicic acid by proteins and its relation to toxicity of silicate dusts.

Abstract: A possible mechanism of biological effects of silicate dusts is the interaction between silicic acid and tissue constituents, and this has been studied in vitro. On incubating silicic acid with lung homogenate, appreciable amounts of silicon were recovered in the trichloroacetic acid precipitate in both organic solvent extract and residual protein. Polyvinyl pyrrolidone inhibited this interaction as well as reducing the dissolution of silicic acid from asbestos dust. The capacity of serum albumin to bind silicic acid was also observed. Chemical interaction between macromolecules and silicic acid could be one of the factors responsible for the biological effects of silicon-containing dusts.

Production of magnetic metallic iron powder

Abstract: PURPOSE:To produce magnetic metallic iron powder having excellent dispersibility in binders and oxidation stability, by forming films of silicic acid and aluminum oxide on the particle surfaces of metallic iron powder by the use of an aq. soln. of silicate and an aluminum salt. CONSTITUTION:An alkaline suspension contg. metallic iron powder, silicate and an aluminum salt is neutralized with an acid of carbon dioxide or the like to form films of silicic acid and aluminum oxide on the particle surfaces of said metallic iron powder. Caustic soda or the like is used as said alkali to control pH to about >= 12. The metallic iron powder is obtd. by reducing iron oxyhydroxide or iron oxide under heating. Sodium orthosilicate or the like is used as the silicate and aluminum sulfate or the like is used as the aluminum salt. The combining ratio thereof is about 1/10-10/1 (based on weight), and the total amt. thereof is about 0.5-10pts.wt. in 100pts. the metallic iron powder. After the iron powder is neutralized with the acid, the powder is washed and is wetted with an org. solvent, whereafter the powder is dried by heating.

Machine base and process for manufacture thereof

Abstract: A support or base for low-vibration mounting of machines or the like is made by hardening a molding material in a mold. The base contains a hardened inorganic material with a density of 2.2 to 3.0, particularly 2.5 to 2.7 g/cm 3 , is made from (a) 15 to 30 weight % of an aqueous 30 to 65% potassium hydroxide-potassium silicate solution in which the SiO 2 :K 2 O molar ratio is 1.0 to 2.0:1; (b) 15 to 35 weight % of an oxide mixture containing amorphous SiO 2 and aluminum oxide and/or hydrated amorphous silicic acid in the dispersed powder form and/or metakaolin; (c) 45 to 65 weight % of inorganic particulate fillers. The potassium silicate solution can be made by dissolving hydrated amorphous silicic acid in potassium hydroxide or its aqueous solution, and in this case, component (b) can consist entirely or partially of metakaolin.

Foam prevention agents, production and use thereof

Abstract: Foam prevention agents are described, characterised by a content of a) a compound of the formula R1-X-A-Y-R2 (I> in which R1 and R2 each have an unsubstituted or hydroxyl-substituted aliphatic or araliphatic hydrocarbon radical each having 7-30 carbon atoms, X and Y are each a group of the formula -CO-, -CO-NH-, -O-CO-NH- or -NH-CO-NH- and A is a hydrocarbon bridge having 1 to 20 carbon atoms, b) paraffin wax, c) hydrophobic silicic acid and d) oil immiscible with water, liquid at 20 DEG and having a boiling point of at least 100 DEG , where the components a) and b) are dissolved and/or dispersed in d) and the component c) is suspended in d), and with or without e) emulsifier, and with or without f) water. The production and use of the agents in aqueous systems which have a tendency to foam formation are also described.

Developer for electrophotography with wet process silicic acid

Abstract: As a developer for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc., there is employed a developer containing a finely divided silicic acid which is a finely divided silicic acid synthesized by a wet process and has a pH value of 6 to 11 when suspended at a concentration of 4% by weight in distilled water and the developer can be positively charged strongly and uniformly to visualize the negative electrostatic images, giving a high quality image.

Membranes based on silicic acid heteropolycondensates and a process for their production

Abstract: Membranes based on silicic acid heteropolycondensates are produced by hydrolytic polycondensation of at least one silicic acid derivative in the presence of water and, if appropriate, a condensation catalyst, the polycondensation being carried out at the surface of a support, which supports the resulting membrane. The reactants can be fed to the surface of the support via the gas phase or via one or more liquid phases.

Zeolite-containing detergent compositions and process for preparing same

Abstract: Spray-dried detergent compositions prepared by spray- . drying aqueous slurries comprising high concentrations of alkali metal silicates in combination with aluminosilicate particles which have been coated with from 100 ppm to 2000 ppm of a cationic surfactant contain fewer large aggregates which can deposit on washed fabrics as floc than is the case when the aluminosilicate is not so coated. The improvement is believed to result from an inhibition of the bridging of aluminosilicate particles by silicic acid.

Modified composite pigment

Abstract: PURPOSE: To provide a modified composite pigment having excellent oil and water absorptivity and chemical stability, by coating CaCO 3 powder with silicic acid or its salt. CONSTITUTION: Heavy or precipitated CaCO 3 particles are treated with a weak acid soln. to activate the surface of the particle. The resulting CaCO 3 particles are suspended in an aq. soln. of an alkaline earth metal hydroxide. The suspension is reacted with silicic acid or a suspension of a sodium silicate soln. or NaON soln. contg. a high proportion of soluble silicates. A silicic acid sol is added thereto, and the mixture is heated while stirring to effect a reaction between reactants, thus obtaining a modified composite pigment having a coating layer of silicic acid (salt) chemically bonded to a CaCO 3 particle nucleus. COPYRIGHT: (C)1985,JPO&Japio

Process of producing a distilled butanediol product of high quality in high yield

Abstract: In accordance with the present invention, there is provided herein a process for producing a distilled butanediol product of high quality in high yield. The process begins with a crude butynediol solution which is made by an ethynylation reaction between aqueous formaldehyde and acetylene. The crude butynediol solution contains at least a metallic ion, usually sodium, magnesium and/or calcium ion, and an anion, particularly, formate ion, and usually also acetate ion, and often silicic acids and silicic acid salts, as impurities, and unreacted formaldehyde. After substantially stripping the solution of the unreacted formaldehyde, the stripped solution is treated with ion exchange resin, including at least a cation exchange resin to remove one or more of the metallic ions present, and as an anion exchange resin to remove the formate ion, and the acetate ion and silicic acids and silicic acid salts, should they be present in the solution. The deionized butynediol solution then is hydrogenated to form a purified butanediol solution, which is fractionally distilled while maintaining the residue thereof in a fluid state to provide a butanediol product of high quality in high yield.

Coagulant plasma-protein solution

Abstract: A coagulant plasma-protein solution obtained by adsorbing stabilized human plasma at least once with 20-40 mg of colloidal silicic acid per gram of plasma protein and separating the adsorbent from the adsorbate, a method of manufacturing the solution, and a pharmaceutical preparation containing the solution and intended for the intravenous treatment of complex disorders of the hemostatic system. The solution is low in fibrinogen and factors XI and XII but otherwise close in composition to the starting material.

Drawing of wire for welding

Abstract: PURPOSE: To maintain consistent drawability and increase productivity, by drawing wire for welding by use of an aqueous dispersion which contains specified amts. of fluorine-contg. resin, silicic acid salt, surfactant and metallic soap. CONSTITUTION: Drawing of wire for welding is perfomed by use of a lubricant consisting of an aqueous dispersion which contains 2.5W8.5wt% fluorine-contg. resin, 10.5W50wt% silicic acid salt, 0.2W4.5wt% surfactant (excluding metallic soap) and 0.15W4.5wt% metallic soap. When the amount of fluorine-contg. resin is less than 2.5wt%, coating film loses strength and drawability of wire becomes poor and when it exceeds 8.5wt%, intake of lubricant by dies is hindered, although coating film has a higher strength. The silicic acid salt improves adhesion of coating film, but when it is used in less than 10.5wt% a thin film is formed which can not stand high surface wear. When the amount exceeds 50wt%, separation of film occurs. The surfactant increases intake of lubricant by dies and the metallic soap improves uniform dispersion of fluorine-contg. resin. COPYRIGHT: (C)1985,JPO&Japio

Manufacture of red iron oxide

Abstract: PURPOSE:To easily obtain lemon red iron oxide with superior lightness by roasting magnetic formed by blowing air into an aqueous ferrous salt soln. in the presence of aluminum salt, silicate, phosphate or the like while adding alkali. CONSTITUTION:To an aqueous ferrous salt soln. is added an aqueous soln. contg. alkali equivalent to or less tha total acid radicals in the ferrous salt soln., and while maintaining the pH at 5.0-6.8, the mixed soln. is air-oxidized to form iron oxide (magnetite) made chiefly of iron oxide having a spinel type structure. At this time, >=1 kind of compound selected from aluminum compounds, silicic acid compounds and phosphoric acid compounds is added to said mixed soln. or produced oxide in a prescribed ratio to iron in the ferrous salt soln. By roasting the magnetic formed by the air oxidation, lemon red iron oxide with superior lightness, yellowness, hinding power, etc. is obtd.

Effect of copper on growth, silicic acid uptake and soluble pools of silicic acid in the marine diatom, thalassiosira weisflogii (bacillariophyceae)1

Abstract: The toxicity of Cu to Thalassiosira weissflogii (Grunow) was investigated, focusing on the internal soluble pool of silicic acid. Silicic acid uptake and growth rates were found to be functions of both the cupric ion activity and the concentration of silicic acid in the growth medium. The soluble pool of Si per cell depended on the balance between the uptake rate and the division rate. The soluble pool in non-dividing cultures reflected simply the uptake rate (and inhibition by copper of the uptake rate), but in dividing cultures the soluble pools had complex patterns with time depending on uptake rates and timing of division. Intracellular soluble pools of silicic acid are a good indicator for the relative inhibition of uptake and growth processes.

Nematocidal and insecticidal composition and method for the control of the said pests

Abstract: A B S T R A C T The invention relates to granules for the control of nema-todes and soil dwelling pests which comprise in an amount of 0-50 % by weight in insecticidal-nematocidal compound and in a total amount of 0.1-20 % by weight - preferably 5-10% by weight - a hydrogen carbonate of the general Formula I MHCO3 (I) and/or a carbonate of the general formula II (M)nCO3 (II) where M is a mono- or divalent metal ion or an ammonium group and n is 1 or 2 and an organic s acid; whereby the weight ratio of the hydrogen carbonate of the general Formula I and/or the carbonate of the general Formula II to the organic acid amounts to 1:10 -10:1 - preferably 3:1 - 1:3; in admixture with solid organic or inorganic carriers and optionally further auxiliary agents, such as hydrophobic silicic acid, sodium aluminium silicate, polyvinyl pyrrolidone-polyvinyl acetate copolymer, magnesium stearate and oils of animal, vegetable or mineral origin.

Process for the treatment of acid waste water containing aluminium and iron

Abstract: 1. A process for the treatment of acid waste water containing aluminum and iron, wherein (a) the acid waste containing small amounts of colloidal silicic acid is heated to just below boiling point so as to precipitate aluminum hydroxide and hydrated iron (III) oxide and is neutralized with calcium oxide and/or calcium hydroxide ; (b) the resultant aluminum hydroxide iron (III) hydroxide precipitate is trated with sodium hydroxide until dissolution of the aluminum hydroxide as aluminate ; (c) the remaining hydrated iron (III) oxide precipitate is separated from the sodium aluminate solution, washed dried and the hydrated iron (III) oxide is pelletised for use as a gas-purifying medium or is converted by thermal treatment into iron (III) oxide suitable for use as pigment ; (d) and the sodium aluminate solution is converted into a crystalline zeolite by reaction with a water glass solution.

High-silica mordenite and process for preparation thereof

Abstract: HIGH-SILICA MORDENITE AND PROCESS FOR PREPARATION TEHEREOF ABSTRACT OF THE DISCLOSURE A high-silica mordenite is provided, which is a synthetic mordenite prepared without performing the dealuminization treatment, and is characterized in that the silica/alumina molar ratio is in the range of from 12 to 30 and the amount of benzene adsorption is 7 to 10% by weight as determined at a temperature of 25°C under a vapor pressure of 35 mmHg. The high-silica mordenite is prepared by a process wherein a reaction mixture having a composition represented by the following oxide molar ratios: Na2/SiO2 = 0.08 - 0.2 SiO2/Al2O = 14 - 55 H2O/Na2O = 100 - 300 and H2O/SiO2 = 10 - 40 is formed using synthetic amorphous silicic acid having an apparent specific gravity of from 0.05 to 0.45 g/ml as a silica source, and the reaction mixture is heated at a temperature of 140 to 180°C with stirring to effect crystallization.

Silicate with high oil absorbency and its manufacture

Abstract: PURPOSE:To inexpensively manufacture a silicate with high oil absorbency by forming an alkaline earth metallic silicate in the 1st stage using fly ash, etc. as starting materials and by increasing the SiO2 content of the silicate in the 2nd stage. CONSTITUTION:Amorphous silicic acid contg. >=50% alkali soluble component or an amorphous silicate such as fly ash is dispersed in a soln. of sodium hydroxide or sodium silicate, and after adding Ca and Mg hydroxides, they are hydrothermally reacted under pressure to form Ca-Mg silicate. To the silicate is added separately prepared silica sol, and they are reacted with heating and stirring to increase the molar ratio of SiO2/CaO. Thus, a ternary system silicate with high oil absorbency is obtd. This silicate consists of SiO2, CaO and MgO in (1-3)/1 molar ratio of SiO2/CaO and (1-2)/1 molar ratio of CaO/MgO, and it absorbs oil by 200-600cc per 100g when measured in accordance with JISK5101.