Showing papers on "Sodium silicate published in 2015"
TL;DR: In this article, the effects of sodium hydroxide and sodium silicate solutions on the properties of fly ash (FA)-granulated blast furnace slag (GBFS) geopolymer were investigated.
314 citations
TL;DR: In this article, the use of solid activators in the manufacture of geopolymer enhances its commercial viability as it aids the development of a one-part “just add water” mixture, similar to the conventional Portland cement-based materials.
250 citations
TL;DR: In this article, the setting time, strength and bond of high-calcium fly ash geopolymer concrete were investigated, where both sodium hydroxide solution and sodium hydride solution were used as alkali activators in every mix.
Abstract: In this paper, setting time, strength and bond of high-calcium fly ash geopolymer concrete were investigated. The high-calcium fly ash was from Mae Moh power plant in northern Thailand. Both sodium silicate solution and sodium hydroxide solution were used as alkali activators in every mix. Sodium hydroxide solution with 10 M, 15 M, and 20 M concentrations, sodium silicate to sodium hydroxide ratios of 1.0 and 2.0, alkaline liquid to fly ash ratio of 0.5 and two curing regimes viz., heat curing at 60±2°C for 24 h and room temperature curing at 23±2°C were used. The results indicated that fresh geopolymer concrete had short setting time of 28–58 min due to the presence of high calcium content of fly ash. In general, strengths and modulus of elasticity increased with the increase in NaOH concentration. For compressive strength, the optimum Na2O content was around 12% of fly ash. The high-strength geopolymer concrete with 28-day compressive strength of 54.4 MPa was obtained for mix with 15M NaOH. The ...
186 citations
TL;DR: In this paper, the joint effect of several mix parameters on the properties of foam geopolymers was investigated through a laboratory experiment of 54 different mortar mixes were, sodium silicate/sodium hydroxide mass ratio (2.5, 3, 4.5), activator/binder mass ratio(0.6, 0.8, 1.0), chemical foaming agent type (H2O2) and sodium perborate (NaBO3)) and foam agent mass ratio content (1, 2, 3%).
180 citations
TL;DR: In this paper, the effect of dosage ratio on the structure and physico-chemical features of the adsorbent was investigated, and its adsorption capability for Methylene blue (MB) and Cu(II) ions was intensively evaluated.
170 citations
TL;DR: In this paper, the authors studied the flotation separation of scheelite from calcite using sodium oleate as collector and acidified sodium silicate as depressant and showed that the use of acidified salt as a depressant can achieve a 3:1 ratio of the ratio of oxalic to salt.
157 citations
TL;DR: In this article, the authors present the encapsulation of mineral compounds as healing materials for cement-based composites, and demonstrate how self-healing can be achieved by utilising cost effective mineral compounds which are also compatible with the host cementitious matrix.
153 citations
TL;DR: In this article, a polyethylene glycol (PEG)/SiO2 shape-stabilized composite phase change material (ss-CPCM) was prepared with the "hazardous waste" oil shale ash.
146 citations
TL;DR: The silica recovered from different sources was found to vary between 52% and 78%.
133 citations
TL;DR: Results showed that geopolymer inorganic membrane efficiently removes Ni(2+) from wastewater because of the combined actions of the adsorption and rejection of this membrane on Ni( 2+) during membrane separation.
129 citations
TL;DR: In this paper, the properties of lightweight geopolymer specimens aerated by aluminium powder were investigated and the compressive strength of all aerated specimens were in the range of 0.9-4.35-MPa.
TL;DR: In this article, the effect of temperature, sodium and potassium hydroxides and different superplasticizers on compressive strength was studied and the results have shown that the compressive strengths increased with increasing temperature, curing time and type of alkali activators.
TL;DR: The effect of activator type, concentration and slag composition on the strength and stability properties of paste backfill (CPB) of high-sulphide tailings using alkali-activated slag (AAS) as binder was investigated in this paper.
TL;DR: In this article, the effect of solids-to-liquids (S/L) and Na2SiO3/NaOH ratios on the production of palm oil boiler ash (POBA) based geopolymer was investigated.
Abstract: This paper investigates the effect of the solids-to-liquids (S/L) and Na2SiO3/NaOH ratios on the production of palm oil boiler ash (POBA) based geopolymer. Sodium silicate and sodium hydroxide (NaOH) solution were used as alkaline activator with a NaOH concentration of 14 M. The geopolymer samples were prepared with different S/L ratios (0.5, 1.0, 1.25, 1.5, and 1.75) and Na2SiO3/NaOH ratios (0.5, 1.0, 1.5, 2.0, 2.5, and 3.0). The main evaluation techniques in this study were compressive strength, X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscope (SEM). The results showed that the maximum compressive strength (11.9 MPa) was obtained at a S/L ratio and Na2SiO3/NaOH ratio of 1.5 and 2.5 at seven days of testing. v
TL;DR: In this paper, a foamed geopolymer material was synthesized from red mud and cullet soda-glass by thermal treatment at 600-800°C for 1.5h.
TL;DR: A series of n-alkanes/silica composites as form-stable phase change materials (PCMs) were synthesized in a sol-gel process using sodium silicate precursor as discussed by the authors.
TL;DR: In this paper, a mixture of calcined kaolin and different alkali activators was used to obtain high compressive strength and stiffness in three-point bending, with the best performance obtained with the sodium silicate solution.
TL;DR: In this article, the effects of sodium silicate to sodium hydroxide ratio on the compressive strength of the mortars at 1 and 7 days before and after exposure to the elevated temperatures of 200°C, 400°C and 600°C.
TL;DR: In this paper, coal fly ash-based geopolymers were investigated as coating materials, and two variables, namely, Na/Al and water/solid ratios, were used to study the effect of the chemical composition of geopolymer on adhesion strength, setting time, microstructure, and thermal stability.
TL;DR: In this article, a simple and effective process for fabricating porous metakaolin-based inorganic polymer spheres was described, and the process for making porous geopolymer spheres (PGS) by a suspension and solidification method was experimentally established.
TL;DR: In this article, a co-precipitation process in an aqueous medium was developed to prepare lignin-based silica composite submicron particles from chemical modified alkali Lignin and sodium silicate.
TL;DR: In this article, a technique of manufacturing alginate-based hybrid aerogels is presented, which involves mixing a second component (biopolymers or filler materials) in a sodium-alginate solution and crosslinking with carbonates of metals like calcium, strontium, cobalt, nickel, zinc and copper.
Abstract: This paper presents a technique of manufacturing alginate-based hybrid aerogels. The technique involves mixing a second component (biopolymers or filler materials) in sodium alginate solution and crosslinking with carbonates of metals like calcium, strontium, cobalt, nickel, zinc and copper. Various biopolymers (lignin, starch, pectin, carrageenan, methyl and carboxymethyl cellulose, gellan gum, and gelatin), polymers (PVA, PEG, Pluronic P-123), inorganic (sodium silicate) and filler materials (titania and hydrophobic silica) were used as the second component. It is suggested to use pressurized carbon dioxide (5 MPa) for gelation and supercritical CO 2 drying (10–12 MPa) to yield aerogels. Obtained aerogels are ultra-porous with low density (as low as 0.017 g/cm 3 ), high specific surface area (200–800 m 2 /g) and pore volume (2.3–9.5 cm 3 /g for pore sizes
TL;DR: In this paper, laterite from Togo (Africa) was used to prepare geopolymers using both phosphoric acid and alkaline sodium silicate solution, and the mechanical properties were determined.
TL;DR: In this paper, the maximum compressive strength and abrasion resistance of Alkali-Activated Slag (AAS) concrete was investigated according to ASTM C1138.
TL;DR: In this paper, bottom ash from coal-fired power plants is used for the production of ceramic tiles, bricks and blocks for various applications and the microwave foaming ability of different slurry  compositions and the physical and mechanical properties of the foamed samples were evaluated.
TL;DR: In this paper, an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days was presented.
Abstract: This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days. The durability was also assessed by measuring water absorption and sorptivity. Ordinary Portland cement concrete was also prepared as control concrete. The grades chosen for the investigation were M20, M40, and M60. The alkaline solution used for present study is the combination of sodium silicate and sodium hydroxide solution with the ratio of 2.50. The molarity of sodium hydroxide was fixed as 12. The test specimens were mm cubes, mm cylinders, and mm discs cured at ambient temperature. Surface deterioration, density, and strength over a period of 14, 28, and 45 days were observed. The results of geopolymer and ordinary Portland cement concrete were compared and discussed. After 45 days of exposure to the magnesium sulfate solution, the reduction in strength was up to 12% for geopolymer concrete and up to 25% for ordinary Portland cement concrete. After the same period of exposure to the sulphuric acid solution, the compressive strength decrease was up to 20% for geopolymer concrete and up to 28% for ordinary Portland cement concrete.
TL;DR: In this article, the authors used x-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infra-red spectrometry (FTIR), laser particle size analyser and scanning electron microscopy with energy dispersive xray analysis (SEM-EDX).
TL;DR: In this article, the effect of an external electric field on the viscosity of glass was investigated and the results showed remarkable electric field-induced softening (EFIS), as application of DC field significantly lowers the softening temperature of glass.
Abstract: Motivated by the advantages of two-electrode flash sintering over normal sintering, we have investigated the effect of an external electric field on the viscosity of glass. The results show remarkable electric field-induced softening (EFIS), as application of DC field significantly lowers the softening temperature of glass. To establish the origin of EFIS, the effect is compared for single vs. mixed-alkali silicate glasses with fixed mole percentage of the alkali ions such that the mobility of alkali ions is greatly reduced while the basic network structure does not change much. The sodium silicate and lithium-sodium mixed alkali silicate glasses were tested mechanically in situ under compression in external electric field ranging from 0 to 250 V/cm in specially designed equipment. A comparison of data for different compositions indicates a complex mechanical response, which is observed as field-induced viscous flow due to a combination of Joule heating, electrolysis and dielectric breakdown.
TL;DR: In this article, a broad modulus range and up to high pH values (∼14) by use of infrared (IR) spectroscopy and silicon nuclear magnetic resonance (29Si-NMR) was investigated, which showed that the modulus dependent pH value leads to more or less charged species, which affects the configurations of the silicate units.
Abstract: Despite that sodium silicate solutions of high pH are commonly used in industrial applications, most investigations are focused on low to medium values of pH. Therefore we have investigated such solutions in a broad modulus range and up to high pH values (∼14) by use of infrared (IR) spectroscopy and silicon nuclear magnetic resonance (29Si-NMR). The results show that the modulus dependent pH value leads to more or less charged species, which affects the configurations of the silicate units. This in turn, influences the alkali-activation process of low CO2 footprint cements, i.e. materials based on industrial waste or by-products.
TL;DR: In this paper, mesoporous silica with controlled pore structure was prepared from bagasse ash as a silica source, with or without polyethylene glycol (PEG) template.