Silicate Modulus Research Articles

Colloidal Properties and Clay Inhibition of Sodium Silicate in Solution and Montmorillonite Suspension

To investigate the interaction mechanism, clay inhibition and compatibility of sodium silicates as shale inhibitor in water based drilling fluid, a variety of properties were characterized. Zeta potential, activity, colloidal stability and particle size were employed to characterize the colloidal properties. Adsorption, cuttings hot-rolling dispersion, linear swelling, pressure and osmosis transmission tests were used to determine the inhibition properties. Results showed that the zeta potential of sodium silicate solution ranging from −45 mV to 0 mV, increased in magnitude with increasing the sodium silicate modulus and pH of solution in the initial stage and decreased with the concentration of monovalent inorganic salts. With the increase of modulus and concentration of sodium silicate, the solution activity generally decreased or colloidal polysilicic acid began to form at a solution concentration above 70 g/L of Na2O⋅2.8SiO2 (2.8SS). The diameter of polysilicic acid increased with 2.8SS concentration, modulus, pH and salt concentration. Adsorption of 2.8SS onto montmorillonite through chemical bonding was boosted with increasing 2.8SS concentration regardless of cuttings addition. The adsorption also rose exponentially with temperature. The activity of the montmorillonite suspension was reduced by the addition of 2.8SS and further decreased by salt addition. 2.8SS was found to exhibit superior inhibition performance compared to KCl, organosilicon, sulfonate asphalt and polyglycol. The pressure transmission was retarded effectively, resulting in the improvement of membrane efficiency of shale clays.

Rheology of Cross-Linked Poly(Sodium Acrylate)/Sodium Silicate Hydrogels

Transparent hydrogels consisting of poly(sodium acrylate) and sodium silicate were synthesized by free-radical polymerization of sodium acrylate (ANa) in an aqueous solution of sodium silicate (i.e. water glass) with the silicate modulus (M) 2.50 and the Midafen R-102 polymer filler, in the presence of sodium thiosulphate/potassium persulphate (NTS/KPS) as the redox initiators and N, N′-methylenebisacrylamide as the cross-linking monomer. The hydrogels, obtained in this way, were rheologically tested, and also the gelling point, dependence of shear stress on shear rate, and oscillation constants were determined. The results indicated that during the cross-linking reaction, which is associated with a gradual building of the three-dimensional gel structure, the reaction mixture changes its rheological behaviour from pseudo-thixotropic at the beginning of the reaction to pseudo- anti-thixotropic in the end. Both elasticity modulus G′ and viscosity modulus G′′ during the reaction and for the cast samples after 24 h have practically the same values and the phase shift angle δ is below 20° which means that we obtained a highly elastic material. It was also found that the elasticity modulus G′ values increase with the content of sodium silicate in the sample.

Fabrication of adiabatic foam at low temperature with sodium silicate as raw material

The process of adiabatic foam, fabricated at low temperature, is described in this research using sodium silicate as the raw material. Fly ash was added to increase the strength of the samples to guarantee the needs of thermal insulation material application. The thermal conductivity, density, compression strength and microstructure were characterized in this paper. The results show that the sintering process, fly ash content and modulus of sodium silicate greatly affected the above properties. Samples with 0.0488W/mK of thermal conductivity, 97kg/m3 of density and 0.44MPa of compression strength were obtained. Therefore, this adiabatic foam has a large potential of insulation application.

Conversion of Straight-Run Gasoline Fraction on Combined Zeolite-Containing Catalysts

Experiments were performed on catalytic hydrogen-free upgrading of low-octane gasoline fractions on zeolite-containing catalysts with various silicate moduli. Chromatographic analysis showed the influence of a change in the molecular-sieve characteristics of zeolite-containing catalysts on the individual and group composition of the obtained gasolines. It was found to be expedient to combine zeolite-containing catalysts with various silicate moduli in the catalyst composite in order to increase the conversion of the feedstock fraction.

Co-Producing Active Carbons and Sodium Silicate from Pyrolyzed Rice Husk by CO<sub>2</sub> Activation Coupled with NaOH Solution Boiling

Active carbon and sodium silicate were produced simultaneously from pyrolyzed rice husk (PRH) by CO2 activation coupled with NaOH solution boiling. Doehlert matrix and Derringer's desirability function were applied to optimizing the boiling conditions to achieve a large specific surface area, a high silica extraction and low alkali consumption. In terms of this purpose, the optimum condition was determined as boiling CO2-activated char with 1mol/L NaOH solution at a liquid/solid ratio of 9.7 mL/g. Under this condition, the modulus of the sodium silicate and the specific surface area (SSA) of the active carbon were 2.62 and 897 m2/g, respectively. The values both reached their respective commercial levels. The pretreatment of the PRH with CO2 activation can markedly increase the SSA of active carbons.

EPR of radiation-induced paramagnetic centers in irradiated sodium silicate glass for immobilization of solid radioactive wastes synthesized in various conditions

The nature of radiation-induced paramagnetic centers (RPC) in glassy materials produced at vitrification of solid radioactive waste (SRW) surrogates with sodium silicate fluxes at the silicate modulus values of 2, 3, and 4 depending on the SRW oxide loading and the preparation method was studied. The connection between the type of RPC formed at silicon-oxygen units of the glass network and chemical durability of the glassy materials was established.

Strength and microstructure of alkali-activated binary blended binder containing palm oil fuel ash and ground blast-furnace slag

In this study, combinations of ultrafine palm oil fuel ash (UPOFA) and ground blast furnace slag (GBFS) have been used to study the compressive strength and microstructure of the alkali-activated GBFS–UPOFA (AAGU) binary blended binder paste. GBFS (G) was added in varying percentages to alkaline activated UPOFA (AAU) such that the ratio of G/U+G varied from 0 to 0.3 at interval of 0.05. Sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) with a final silicate modulus (Ms=SiO2/Na2O) of 1.58 were used as activators. Pozzolanic materials (G+U), activators, and free water were combined by weight ratios as: 1/0.35/0.02. A 28-day compressive strength of 44MPa was achieved for G/U+G of 0.2 cured for 24h at 60°C. Finally, characterization was done using X-ray diffraction, SEM and FTIR and the analyses revealed that GBFS contributes significantly to the mechanical strength by pore filling effects, and the formation of additional calcium (aluminate) silicate hydrate (C(A)SH).

Complex Catalysts for Direct Synthesis of Dimethyl Ether from Synthesis Gas. Part I: Study of the Catalytic Properties

The results of the development of combined process for production of dimethyl ether (CuO/ZnO/Al2O3) and methanol dehydration (γ-Al2O3, zeolite (ZSM-5 type) with a silicate modulus (М) 20, 30, 60, 80, 100, and 200) are presented. The experiments on the influence of the catalysts loading and catalytic conditions were carried out (Р=3 MPa, Н2/СО=2, Т=553 К). It was established that the use of ZSM-5 zeolite catalysts with silicate modulus of 30 allows obtaining the yield of dimethyl ether up to 39%. It was stated that catalytic systems were stable during 180 h.

Influence of sodium silicate modulus on iron ore flotation with sodium oleate

This paper presents the influence of sodium silicate modulus on iron ore flotation with sodium oleate collector. Bench flotation tests were performed at pH7 with actual iron ore from Quadrilátero Ferrífero, Brazil, with 42.8% Fe and 37.2% SiO2. Iron recovery averaged above 90% and the Fe contents in the concentrate were above 55%. The highest values of Fe grade and lowest of SiO2 were obtained with low levels of pulp density and sodium silicate dosage and with high level of sodium oleate. Increase of sodium silicate modulus had a small influence on response variables.

Properties of Alkli-Activated Slag Cement Compounded with Soluble Glasses with a High Silicate Modulus

Properties of alkali-activated slag cements compounded with soluble glasse with a high silicate modulus Ms=2.6 were detailedly studied in this paper, including compressive strength and flexure strength characterictics at the ages of 3,7,28 days and flow values of fresh cement mixtures on a jolting table. As a result, with the compressive strength at the age of 28 days of 95.6-107.8 MPa has been developed, and the flow values and strength characteristics of alkali-activated slag cement mortars increased with increase in a water to cement (alkaline activator solution to slag) ratio, and the flow value (determined on the cement mortar mixtures) would reach 145 mm. Moreover, the development speed of strength characteristics of mortar specimens would be affected negatively by increasing of water demand (requirement).

Workability and Setting Time of Alkali Activated Blast Furnace Slag Paste

Abstract This paper reports the results of an experimental investigation of blast furnace slag paste activated by potassium hydroxide and sodium silicate. Reasonable workability and setting times were maintained. The workability was measured in terms of flow diameter. The loss of flow with time was also studied. The major parameters studied were water/binder ratio, alkali content, silicate content, slag/activator ratio, silicate modulus, and sodium silicate/potassium hydroxide ratio, and their effects on workability and setting time are presented. It was found that the workability and setting time of alkali activated ground granulated blast furnace slag paste are dependent basically on the alkali content, silicate content, and silicate modulus. Locally available blast furnace slag has been utilized, and its potential as source material has been verified. This information will be useful to manufacturers and researchers.

Identification of sodium silicate species used as flotation depressants

Sodium silicate (water glass) is a modifier reagent widely used in flotation with the function of a depressant or dispersant. The interaction between sodium silicate and mineral surfaces is still not well understood. This investigation aimed to illuminate the sodium silicate action mechanism as a depressant in the flotation of the minerals quartz and calcite. The experiments were done with high-purity mineral samples in the particle size range below 147 µm. The microflotation tests in a modified Hallimond tube showed that, in all systems tested, the efficiency of sodium silicate increased with the concentration. At concentrations above 1,500 g/t, almost total depression (96% for calcite and 97% for quartz) was achieved. The variation of sodium silicate modulus did not alter the quartz flotation performance in the presence of amine (150 g/t). The most efficient depression pH range was observed between 5 and 8. Above pH 10, the depressant action of sodium silicate was negligible. The infrared spectra obtained at pH 7 after silicate contact showed the presence of the groups OH and Si-OH, both suggesting that the adsorption of the neutral species Si(OH)4, as well as siloxane groups (Si-O-Si), attributed to adsorption of polymeric species. Sharing electron pairs is the proposed adsorption mechanism between Si(OH)4 and polymeric species and the surface sites (Si-O on quartz and Ca-O on calcite). At pH 11, the electrostatic repulsion prevents the species adsorption, impairing the sodium silicate action.

Synthesis of High-purity Spherical Silica Nanoparticles from Powder Quartz by Improved Sol–Gel Method

Abstract High-purity spherical silica nanoparticles have been successfully synthesized using powder quartz as silica sources in an improved sol–gel method. The effects of the modulus (molar ratio SiO2/Na2O) of sodium silicate and poly(ethylene glycol) (PEG) on the properties of silica nanoparticles were investigated. The results suggested that with the increase of modulus, the purity of silica nanoparticles increased. The higher purity (99.92 wt %) products can be obtained from the modulus of 3. Moreover, it was also found that the particle size, distribution, and dispersion significantly depend on the concentration of PEG. The silica nanoparticles with average size of 60 nm are well-dispersed and show a narrow size distribution when the PEG concentration is 2 wt %. The results suggest that it is feasible to prepare high-purity spherical silica nanoparticles using powder quartz as silica sources.

Key role of sodium silicate modulus in synthesis of mesoporous silica SBA-15 rods with controllable lengths and diameters

Monodispersed and highly ordered mesoporous silica SBA-15 rods with controllable size were synthesized by using triblock copolymer Pluronic P123 (EO20–PO70–EO20) as a structure-directing agent and sodium silicate as silica source without any additives. The rods' length (800–1200nm) and diameter (300–500nm) were tuned by varying the modulus (molar ratio SiO2/Na2O) of sodium silicate. The effect of the modulus on the structure and morphology of mesoporous silica SBA-15 was investigated. The size and structural order of the products were found to be greatly affected by modulus. The results suggested that with the increase of modulus, the length of rods decreased and the diameter increased. Moreover, a higher modulus favored the formation of higher ordered SBA-15 rods.

Deposition of protective coatings from aqueous solutions of silicates of tertiary ammonium bases

The possibility of using aqueous solutions of organic ammonium base silicates to produce protective adhesive films for paint and varnish coatings on a steel surface is examined. It is established that the protective ability and moisture resistance of films do not depend on the magnitude of a silicate modulus of tertiary ammonium bases, solution concentration, and temperature. The optimal concentration (10 g/L) and temperature range (45–50°C) of the working solution, as well as the time for its processing, are determined. It is shown that the following treatment of the organosilicon coating with the solution bearing cerium (III) ions improves its protective potency. It is revealed that the protective ability of the coatings increases with the reduction of the length of a hydrocarbon radical.

Structure formation of cellular heat-insulation material from cold-solidifying liquid-glass composition

The possibility of obtaining foamed heat-insulation material at room temperature on the basis of liquid glass with calcium-containing additives is examined. Amethod of controlling gas generation and solidification of a liquid-glass composition by changing the silicate modulus of liquid glass is shown.

Preparation and evaluation of silica xerogel monolithic column

Using potassium silicate as silicon source, formamide as catalyst, a series of silica xerogel monolithic columns with different consistencies were prepared. The column bed would not rupture and collapse during drying at high temperatures. This is the biggest advantage compared with the inorganic monolithic columns using alkoxy silane as precursor. The effect of the modulus of potassium silicate on the physical structure of the monolithic column was investigated. The monolithic silica columns were characterized by scanning electron micrograph (SEM) and nitrogen adsorption. The relationship between column pressure and flow rate was evaluated. The column efficiency for anthracene was tested. The breakthrough curve for toluene was studied. The results showed that the column bed could maintain good stability at high temperatures, high column pressures, and high flow rates. The column efficiency of 41,400 plates/m was achieved for anthracene. The column capacity for toluene was 61 ng.

Study on the Properties of Magnetization Modified Sodium Silicate Sand

Based on the magnetization technological parameters optimized of sodium silicate, the properties of modified sodium silicate sand with ester hardening have been systematically investigated. The results indicated that the bonded strength of sodium silicate treated in the magnetic field may be increased by 30%~40%, the minimum addition content of sodium silicate in mold sand may reduce to 2.5%, and thus it improves markedly the collapsibility of the sodium silicate bonded sand. The used time of modified sodium silicate sand increases to 25%, but the effect of magnetization of sodium silicate will be disappeared after 24 hours, and the magnetization decaying speed enhanced with increasing the modulus of sodium silicate. The magnetization modification has a good effect on the high modulus sodium silicate than the low modulus sodium silicate.

Development of Non-Autoclaved Aerated Concrete by Alkali Activated Phosphorus Slag

The feasibility of manufacturing non-autoclaved aerated concrete using alkali activated phosphorus slag as a cementitious material was investigated in this paper. Liquid sodium silicate with various modules (the molar ratio between SiO2 and Na2O) was used as alkali activator and a part of phosphorus slag was replaced with fly ash which was used to control the setting time of aerated concrete. The influences of the fly ash, curing procedure, modulus of sodium silicate solution and concentration of alkalis on the compressive strength and bulk density of non-autoclaved aerated concrete have been studied. Moreover, the types of the hydration products were investigated using XRD and SEM. The results indicate that: the compressive strength of aerated concrete was influenced by concentration of alkalis obviously. The compressive strength of 11.9MPa and the bulk density of 806kg/m3 were obtained with an activator of 1.2 modulus of sodium silicate and 6% concentration of alkalis under the circumstance of 60°C curing for 28 days.

The Study of a Kind of New Synthetic Paper Coating Thickness Agent

In this paper, Water glass and sulfuric acid were used as raw materials to do the synthesis of hydrated silica by the method of precipitation, and then hydrated silica is applied in paper coating. By examining the changes of the coated paper’s various properties to study the effects of different reaction conditions to the final products. And then we obtained a optimal synthesis conditions: sulfuric acid concentration 25%, reaction time 50min, reaction temperature 80°C, sodium silicate modulus 2.8, stirring speed 150r/min, the relative amount of sodium sulfate content compared to SiO2 is 25% .And at last the outward appearance of the hydrated silica and the structural changes in paper coating were observed by scanning electron microscopy.