scholarly journals The phenomena arising from the addition of hydrogen peroxide to the sol of silicic acid

1927 ◽  
Vol 114 (768) ◽  
pp. 517-521
Keyword(s):  
Hydrogen Peroxide ◽  
Hydrochloric Acid ◽  
Sodium Silicate ◽  
Silicic Acid ◽  
Room Temperature ◽  
Gas Bubbles ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Usual Manner ◽  
Acid Gel

The formation of gas bubbles in silicic acid gel (or, in fact, any gel) has been described by Hatschek, and he expresses the view that “such bubbles, which can be produced by a variety of means, are always lenticular, while gas bubbles in a liquid at rest—however viscous—are, of course, spherical. It is possible to produce such bubbles during the transformation, and to note an abrupt change from the spherical to the lenticular shape, which, as stated, cannot be explained by a mere increase in viscosity.” Experimental. Preliminary Experiment. Bubbles were caused to form in the gel of siliic acid in the following manner:— A mixture of equal volumes of sodium silicate solution (D = 1·15) and hydrochloric acid (3N) was prepared in the usual manner (by using solutions of such concentrations as would cause gelation in 1 to 2 hours). After the mixture had cooled down to room temperature, 2 c.c. of twenty-volume hydrogen peroxide solution were added and the resulting mixture allowed to stand. The experiment was carried out in a small rectangular vessel to facilitate observation.

Effect of Curing Conditions on the Mechanical Properties of Fly Ash-Based Geopolymer without Sodium Silicate Solution

2014 ◽  
Vol 699 ◽  
pp. 15-19 ◽  
Author(s):  
Rosniza Hanim Abdul Rahim ◽  
Khairun Azizi Azizli ◽  
Zakaria Man ◽  
Muhd Fadhil Nuruddin
Keyword(s):  
Compressive Strength ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Room Temperature ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Curing Temperature ◽  
Curing Time

Geopolymer is associated with the alkali activation of materials rich in Si and Al, and alkali activator such as sodium hydroxide is used for the dissolution of raw material with the addition of sodium silicate solution to increase the dissolution process. However, the trend of strength development of geopolymer using sodium hydroxide alone is not well established. This paper presents an evaluation on compressive strength of fly ash–based geopolymer by varying curing time with respect to different curing temperature using sodium hydroxide as the only activator. The samples were cured at room temperature and at an elevated temperature (60°C). Further analysis on the microstructure of geopolymer products cured at 60°C was carried out using Field Emission Scanning Microscopy (FESEM). It can be observed that the compressive strength increased as the curing time increased when cured at room temperature; whereas at elevated temperature, the strength increased up to a maximum 65.28 MPa at 14 days but gradually decreased at longer curing time. Better compressive strength can be obtained when the geopolymer was cured at an elevated temperature compared to curing at room temperature.

scholarly journals Printability and Setting Time of CSA Cement with Na2SiO3 and Gypsum for Binder Jetting 3D Printing

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2811
Author(s):  
Okpin Na ◽  
Kangmin Kim ◽  
Hyunjoo Lee ◽  
Hyunseung Lee
Keyword(s):  
3D Printing ◽  
Sodium Silicate ◽  
Setting Time ◽  
Sodium Silicate Solution ◽  
Preliminary Test ◽  
Silicate Solution ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate ◽  
Parametric Studies ◽  
Binder Jetting

The purpose of this study is to optimize the composition of CSA (calcium sulfoaluminate) cement with sodium silicate (Na2SiO3) and gypsum for binder jetting 3D printing. The preliminary test was carried out with an applicator to decide the proper thickness of one layer before using the 3D printer. A liquid binder was then selected to maintain the shape of the particles. Based on the results, the optimal mixture of dry materials and a liquid activator was derived through various parametric studies. For dry materials, the optimum composition of CSA cement, gypsum, and sand was suggested, and the liquid activator made with sodium silicate solution and VMA (viscosity modified agent) were selected. The setting time with gypsum and sodium silicate was controlled within 30 s. In case of the delayed setting time and the rapid setting mixture, the jetting line was printed thicker or thinner and the accuracy of the printout was degraded. In order to adjust the viscosity of the liquid activator, 10% of the VMA was used in 35% of sodium silicate solution and the viscosity of 200–400 cP was suitable to be sprayed from the nozzle. With this optimal mixture, a prototype of atypical decorative wall was printed, and the compressive strength was measured at about 7 MPa.

scholarly journals Silica extraction from bauxite reaction residue and synthesis water glass

2021 ◽  
Vol 10 (1) ◽  
pp. 268-283
Author(s):  
Yunlong Zhao ◽  
Yajie Zheng ◽  
Hanbing He ◽  
Zhaoming Sun ◽  
An Li
Keyword(s):  
Sodium Silicate ◽  
Water Glass ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Hydrated Calcium Silicate ◽  
Precipitated Silica ◽  
Alumina Gel ◽  
Silica Alumina ◽  
Element Removal ◽  
Hydrated Calcium

Abstract Bauxite reaction residue (BRR) produced from the poly-aluminum chloride (PAC) coagulant industry is a solid acidic waste that is harmful to environment. A low temperature synthesis route to convert the waste into water glass was reported. Silica dissolution process was systematically studied, including the thermodynamic analysis and the influence of calcium and aluminum on the leaching of amorphous silica. Simulation studies have shown that calcium and aluminum combine with silicon to form hydrated calcium silicate, silica–alumina gel, and zeolite, respectively, thereby hindering the leaching of silica. Maximizing the removal of calcium, aluminum, and chlorine can effectively improve the leaching of silicon in the subsequent process, and corresponding element removal rates are 42.81%, 44.15%, and 96.94%, respectively. The removed material is not randomly discarded and is reused to prepare PAC. The silica extraction rate reached 81.45% under optimal conditions (NaOH; 3 mol L−1, L S−1; 5/1, 75°C, 2 h), and sodium silicate modulus (nSiO2:nNa2O) is 1.11. The results indicated that a large amount of silica was existed in amorphous form. Precipitated silica was obtained by acidifying sodium silicate solution at optimal pH 7.0. Moreover, sodium silicate (1.11) further synthesizes sodium silicate (modulus 3.27) by adding precipitated silica at 75°C.

A Study on a Green Route to Preparation of Silica Powders with Rice Husk Ash

2014 ◽  
Vol 1010-1012 ◽  
pp. 1015-1019
Author(s):  
Ze Xin Yang ◽  
Lin Dong ◽  
Meng Wang ◽  
Huan Li
Keyword(s):  
Sodium Bicarbonate ◽  
Sodium Silicate ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Sodium Hydroxide Solution ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Raw Material ◽  
Transmission Electron ◽  
Thermal Analyzer

The main purpose of this article is to develop an environmentally friendly and economically effective process to produce silica from rice husk ash. Sodium silicate solution was prepared by the reaction of rice husk ash and sodium hydroxide solution, and then the sodium silicate solution was used as the raw material for the preparation of silica with sodium bicarbonate. During the reaction, the by-product can be passed into CO2 to prepare sodium bicarbonate what can be reutilized. Experimental route achieved resource recycling and environment-friendly, low energy consumption, zero emissions and so on. Meanwhile the microstructures of the silica powders were characterized by Transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Thermo gravimetric/Differential thermal analyzer (TG-DTA).The purity of silicon was up to 99.43% and the particle size was 200-300nm.

Consolidation mechanism of materials obtained from sodium silicate solution and silica-based aggregates

2011 ◽  
Vol 357 (15) ◽  
pp. 3013-3021 ◽  
Author(s):  
Séka Simplice Kouassi ◽  
Monique Tohoué Tognonvi ◽  
Julien Soro ◽  
Sylvie Rossignol
Keyword(s):  
Sodium Silicate ◽  
Sodium Silicate Solution ◽  
Silicate Solution

scholarly journals Pengaruh Keasaman Medium dan Imobilisasi Gugus Organik pada Karakter Silika Gel dari Abu Sekam Padi

2005 ◽  
Vol 8 (3) ◽  
pp. 74-80
Author(s):  
Sriyanti Sriyanti ◽  
Taslimah Taslimah ◽  
Nuryono Nuryono ◽  
Narsito Narsito
Keyword(s):  
Sodium Silicate ◽  
Silica Gel ◽  
Sodium Silicate Solution ◽  
Thiol Group ◽  
Silicate Solution ◽  
Rice Hull ◽  
Amino Group ◽  
Rice Hull Ash ◽  
Host Matrix ◽  
Medium Acidity

Silica gel is well known as a material that may be used as adsorbent, host matrix for catalyst, etc. Hence, synthesis of silica gel from rice hull ash has been done by evaluation of the effect of medium acidity and organic group immobilized in the snythesis of silica gel.Synthesis of silica gel was done by adding sodium silicate solution from rice hull ash to hydrochloric acid until pH 3, 5 and 7. Immobilization of thiol group and amino group in silica was done by adding 3-mercaptopropyltrimethoxysilane or 3-aminopropyl-trimethoxysilane to sodium silicate solution and hydrochloride acid solution until pH: 7. The products were characterized by X-ray deffractometer and FTIR Spectroscopy.Results showed that porousitas of silica increased with increasing medium acidity ( decreasing pH medium).Immobilization thiol or amino group in silica added a functional group on silica but did not destroy primary structure of silica gel.Key Words: Silica Gel, Rice Hull Ash, 3-mercaptopropyltrimethoxysilane, 3-aminopropyl-trimethoxysilane.

scholarly journals Pressure-Induced Geopolymerization in Alkali-Activated Fly Ash

2018 ◽  
Vol 10 (10) ◽  
pp. 3538 ◽  
Author(s):  
Sol Park ◽  
Hammad Khalid ◽  
Joon Seo ◽  
Hyun Yoon ◽  
Hyeong Son ◽  
...  
Keyword(s):  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Elevated Pressure ◽  
X Ray Diffraction ◽  
27Al Mas Nmr ◽  
Alkali Activated

The present study investigated geopolymerization in alkali-activated fly ash under elevated pressure conditions. The fly ash was activated using either sodium hydroxide or a combination of sodium silicate solution and sodium hydroxide, and was cured at 120 °C at a pressure of 0.22 MPa for the first 24 h. The pressure-induced evolution of the binder gel in the alkali-activated fly ash was investigated by employing synchrotron X-ray diffraction and solid-state 29Si and 27Al MAS NMR spectroscopy. The results showed that the reactivity of the raw fly ash and the growth of the zeolite crystals were significantly enhanced in the samples activated with sodium hydroxide. In contrast, the effects of the elevated pressure conditions were found to be less apparent in the samples activated with the sodium silicate solution. These results may have important implications for the binder design of geopolymers, since the crystallization of geopolymers relates highly to its long-term properties and functionality.

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