Silicate Binder Research Articles

Guniting of the lining of furnaces for heating of steel billets

A method of guniting of the rolling mill heating furnaces during shutdown for cold repairs and with a lining surface temperature of 900–1200°C was developed with the use of guniting powders produced by industry of aluminosilicate and basic compositions with hydraulic and silicate binders. The introduction of composite guniting of the lining in the cold and hot conditions makes it possible to reduce the volume of lining repair work by 10–15 m3 per furnace and the consumption of brick refractories by 0.1 kg per ton of steel rolled and to increase the life of the lining by 1.5–2.0 times.

スラリーキャスティングによる多孔質焼結体の製造 ＩＩ 静電植毛を利用した表面多孔質材の開発

Porous metal which has one directional porosity perpendicular to the surface, can be produced by the combination of slurry casting and fiber planting. First, fine short metal fiber is planted on the surface by electrostatic fiber planting, i.e.flocking and secondly metal powder slurry including ethyl silicate binder is casted on the fiber planted surface. At the subsequent sintering, metal powder is melted and infiltrated into metal powder matrix, which yieds long and one directional pores. Here, Cu fiber and Fe powder are used and electric coinductive vacuum chuck for grinding was experimentally producted.

スラリーキャスティングによる多孔質焼結体の製造 Ｉ 材料と成形方法

Porous metal with complicated shape can be produced by slurry casting followed by sintering. Iron base porous metal was experimentally carted using 19wt% etyl silicate binder which has volatile and self hardening properties in order to obtain the sufficient porosity and green strength for handling without consuming long drying time. Further the addition of fine short metal fiber made not only the increase of green and sintered products but also the uniformity of material composition in the casting. By selecting suiutable material and casting conditions, maximum bending strength of 2500kgf/cm2 with 24% porosity was obtained in 8% dimensional shirinkage and 32% porosity with 300kgf/cm2 bending strength in a almost 0% shirinkage.

An NMR-study of the ester curing of sodium silicate binders

The sensitivity of the equilibrium between different silicate ions to any changes in concentration, pH or temperature makes the study of concentrated alkali silicates solutions difficult. The modern technique of NMR 29Si spectroscopy allows the direct investigation of the chemistry of silica in concentrated solutions. Both the equilibrium state and the kinetics of reactions may easily be studied with this method. In the present work, the NMR-spectra of different reacting systems containing sodium silicate solutions and ester mixtures were studied. Three sodium silicate solutions (ratio SiO 2/Na 2O in the range 2.2–3.3) were cured with each of four ester mixtures, based on di- and triacetin. On the basis of these results, some practical conclusion, especially with respect to bench life, are proposed and discussed. Although the generally accepted model of silicate condensation, which assumes gradual progress from the smallest structural units to big colloidal particles, might be valid in the lower range of pH and/or concentrations, it does not fit the experimental data obtained from concentrated solutions with pH over 11.0. Gelling under such conditions appears as rather a random process, affecting simultaneously all the silicate ions existing in solution. The polycondensation of silicates is too rapid in relation to the rate of silicate rearrangement and does not influence the distribution of silica between different building units in solution.

Effects of tetraethyl orthosilicate binder on the characteristics of AN SnO 2 ceramic-type semiconductor gas sensor

As part of the research to improve the long-term stability of sintered SnO 2 semiconductor gas sensors, we examined the effect of the degree of polymerization (referred to as DP) of ethyl silicate binders added to the sensors on their characteristics. DPs in the range one to four were investigated. By using a binder with a large DP gas sensibility is increased and the sensor resistance is decreased. Humidity dependency and long-term stability are improved by using a binder with a smaller DP. A binder whose DP is more than 2.0 is needed in order to obtain the necessary mechanical strength of the sensor. We concluded that the binder's DP should be 2.5 for the sensor to be stable during long-term operation. Through measurements of H 2 oxidation activity and temperature-programmed desorption for H 2O and O 2, we concluded that the long-term change in the sensor sensitivity is based on the change in its catalytic activity caused by the increase or decrease of the amount of the hydroxyls on its surface.

Physical-chemistry study of sodium silicate as a foundry sand binder

Colloidal chemistry is a tool in developing the physics and chemistry of sodium silicate as a foundry binder. A review is presented of the pertinent literature on silicate structures, hydrolysis products of silicic acids, the mechanism of polymerization of polysilicic acid in sodium silicate solutions, and factors affecting the rate of polymerization and gelation. In addition, some recent experimental results from the author's work are presented and used to support some of the theoretical concepts and to further elucidate the hardening mechanism of sodium silicate binder in foundry sands.

Thermal-shock resistance of corundum-mullite masses

The thermal-shock resistance of corundum-mullite specimens of a grainy structure made from semidry masses is significantly increased with the formation of a porous matrix phase in the structure of the articles or with the creating of pores at the boundaries between the binding mass and the coarse grains of filler. Resistance to thermal shock in the vibrocompacted corundum-mullite masses in an ethyl silicate binder increases with the partial replacement of the coarse-grain corundum by sintered or acicular mullite and also with the addition of finely dispersed additions of SiC and quartz to the mass.

Some features of the production of thermal-shock-resistant cast corundum materials in ethyl silicate binders

The use of ethyl silicate binders of an optimal composition makes it possible to produce cast corundum articles with a mullite-corundum binder with excellent characteristics. The best combination of properties is found in the articles when binders of optimal composition, close to stoichiometric, are used in the hydrolysis reaction of the ethyl silicate. The destruction and sintering processes in the corundum casts in an ethyl silicate binder during heat treatment are produced by the destruction kinetics of the hydrolysis products of the ethyl silicate and by the presence in them of active SiO2. The sintering of articles of such a composition begins at ∼ 1100°C. The excellent thermal-shock resistance of the ceramic made from masses with ethyl silicate binders and the slower destruction of these ceramics result from the rational phase composition and structure of the material.

A refractory ceramic with ethyl silicate binder

A refractory ceramic with ethyl silicate binder

Chemical Stabilisation of Sand : Part* II Construction and Studies of 50m X 4m Road

An experimental track (50m X 4m) was constructed on a loose sand bed by using two chemical-sand composition containing either 9 per cent urea formaldehyde (UF) resin or 11 per cent sodium silicate binder (on solid content basis). The trafficability studies on 5-6 cm thick stabilised track was found to vary from 1625 to 1700 psi in UF stabilised track and from 1340 to 1460 psi in silicate stabilised track. The effect of resin, desert environmental conditions and trafficability studies showed cumulative loss of load bearing capacity from 1625-1700 to 645-1125 psi.

Strength properties of guniting compounds of sintered magnesite and chromite with added silicate binders

Strength properties of guniting compounds of sintered magnesite and chromite with added silicate binders

The effect of the basicity of the silicate binder on the strength of iron ore pellets during reduction

The effect of the basicity of the silicate binder on the strength of iron ore pellets during reduction

The chemistry of ethyl silicate binders in refractory technology

AbstractThe chemistry of the processes involved when an alkyl silicate such as ethyl silicate acts as a binder in refractory technology is described. The gel forming process involving catalysed hydrolysis and condensation of ethyl silicate and tetra‐alkyl silicates has been studied using amine catalysts. Thermal studies of gels obtained from technical ethyl silicate and of gels obtained from technical ethyl silicate incorporated in refractory materials, together with infrared spectroscopy studies of gels obtained from technical ethyl silicate, suggest the nature of the degradation products, and the weight‐loss patterns observed support the proposed mechanisms.

The chemistry of ethyl silicate binders in refractory technology

The chemistry of the processes involved when an alkyl silicate such as ethyl silicate acts as a binder in refractory technology is described. The gel forming process involving catalysed hydrolysis and condensation of ethyl silicate and tetra-alkyl silicates has been studied using amine catalysts. Thermal studies of gels obtained from technical ethyl silicate and of gels obtained from technical ethyl silicate incorporated in refractory materials, together with infrared spectroscopy studies of gels obtained from technical ethyl silicate, suggest the nature of the degradation products, and the weight-loss patterns observed support the proposed mechanisms.

Guniting the lining of oxygen-blown converters

A technology was developed for the semidry guniting of the 130-ton oxygen-blow converters of the Krivorozhstal' Plant with a magnesia gunite mix containing a carbon—silicate binder. Guniting resulted in an increase in the campaign by 56 melts on average at a gunite consumption of 0.25 kg/ton of steel.

Solid Film Lubrication of Worm Gears

A study was conducted to determine the feasibility of lubricating worm gears with bonded solid film lubricants. An apparatus for determining gear efficiency and lubrican film wear-life was fabricated. Several tests using conventional oil lubrication were conducted to establish baseline gear efficiency data. Efficiency and wear-life tests were made with four solid lubricant films, two of them incorporating MoS2 and Sb2O3 in organic polyimide resin binders, and two using MoS2, graphite and gold or bismuth in an aluminum phosphate or sodium silicate binder. Experimental data indicate that solid film lubrication of worm gears is feasible, without a serious loss of efficiency in situations where limited wear-life is acceptable.

Studies on CO2 Process Particularly on Viscosity of Sodium Silicate Binders

Studies on CO₂ Process Particularly on Viscosity of Sodium Silicate Binders

Translucent behavior of opaque cornea; its possible application in corneal blindness.

This paper is concerned with corneal blindness and the possibility of restoring image perception in cases of corneal scarring. Experiments in this field gave me reason to believe that a new approach may be possible in the production of images. For this study I made a light-proof telescopic sliding tube with a length varying between 10 and 35 cm., with a diameter of 25 mm., both ends covered with black mastic tape, with a 10 mm. round opening at each end. I had two completely opaque human corneas and two cataractous lenses at my disposal, removed by surgery. The corneas were kept in a slightly hypertonic alkaline Ringer's solution in which they were well preserved for a few weeks. One side of a clear, thin coverglass was first precoated with sodium silicate binder and then an ultraviolet sensitive zinc sulfide phosphorescent powder was blown on by a hot air blast.

A New Inorganic Cement Mortar For Sulfuric Acid Service★

Abstract Silicate cement mortars, consisting of a chemically inert solid filler containing a fluoride setting agent and a liquid sodium or potassium silicate binder, have been used for many years in acid-proof construction for high temperature, strong acid service. While silicate cements have performed well under unusually tough conditions, they are not without their shortcomings in sulfuric acid service. Instances of corrosive attack are explained by breakdown of the setting agent and hydrate or alum formation. A new material of construction, a silica cement mortar, has been developed which shows promise in sulfuric acid service. The binder is a silica sol instead of a solution of a sodium or potassium silicate which is alkaline. The setting agent permits an orderly gelation of silica resulting in a strong mortar. Unit cell dimensions are given for a number of sulfates and alums. Seven physical properties are listed and compared for sodium silicate mortar, potassium silicate mortar and silica mortar. The comprehensive strengths of these three materials after immersion in sulfuric acid are reported. 6.6.5

Atmospheric corrosion testing

Mineral trioxide aggregate (MTA) is a new type of biocement for endodontic use. MTA, also known as silicate binder, contains, as its main components 3CaO·SiO2, 2CaO·SiO2, 3CaO·Al2O3, 4CaO·Al2O3·Fe2O3. Depending on the amount of coloring ions (mainly Fe) MTA can be gray (GMTA) or white (WMTA). In this study the sol-gel synthesis (Pechini method) of 2CaO·SiO2 and 3CaO·Al2O3 is presented, the main components of WMTA, as well as of WMTA and partially stabilized cements (PSCs). PSCs are also MTA type silicate cements in which Zn and F were added in order to create crystal defects and a high energy state in order to decrease the cement setting time.X-ray diffraction analysis (XRD) was used for the assessment of phased composition of the intermediate products and final oxide powders. Electron microscopy techniques (SEM and TEM) were used to provide information about the oxide powder morphology and to estimate the average particle size and crystallinity degree of the synthesized materials.The bioactivity of 2CaO·SiO2, 3CaO·Al2O3, and WMTA was assessed by soaking in simulated body fluid and the nature of formed compounds was determined by XRD or infrared spectroscopy. In vitro cytotoxicity assay was also performed for WMTA and PSCs obtained by this method.